A low-coordinate platinum(0)-germylene for E–H bond activation and catalytic hydrodehalogenation

Article https://doi.org/10.1038/s41467-024-53940-9 A low-coordinate platinum(0)-germylene for E–H bond activation and catalytic hydrodehalogenation Sonia Bajo, Enrique Soto , Marta Fernández-Buenestado, Joaquín López-Serrano &JesúsCampos Pairing transition metals and heavier tetrylenes (Si, Ge, Sn, Pb) holds great potential for cooperative bond activation and catalysis. In this work, we investigate the reactivity of a low-coordinate Pt(0)/Ge(II) system that emerges from the reaction between the monoligated platinum(0) precursor [(PMe 2 ArDipp2)Pt(olefin)] with germylene dimer [ArDipp2GeCl] 2 (where ArDipp2 =C 6 H 3 −2,6-(C 6 H 3 −2,6-iPr 2 ) 2 ). The resulting complex reveals ability for cooperative bond activation. Stoichiometric reactions with dihydrogen, water, methanol, ammonia and alkynes unveil theformationofPt(II)-germylcom- pounds, characterized by distinct isomeric forms, whose flexibility derives from the particularly low-coordination. We explore its catalytic potential in the hydrodehalogenation of aliphatic, aromatic and main-group halides under dihydrogen atmosphere using both thermal and photochemical conditions, demonstrating promising conversions even for more challenging alkyl chlorides. Heterobimetallic complexes constructed around a transition metal andalow-valentmaingroup element havegarneredrenewedattention owing to their structure, bonding, and reactivity1,2.Notably,heavier divalent group 14 elements (Si, Ge, Sn, Pb; heavier tetrylenes) combinedwithtransition metalsrepresentprominentandtrendyexamples within this category3. Despite being discovered earlier than their lighter carbene counterparts4, heavier tetrylenes were swiftly overshadowed by their carbon versions, primarily due to the efficacy of those as innocent ligands in metal catalysis5. However, it is precisely the unique ability of heavier tetrylenes to function as non-innocent platforms that sets them apart. These compounds exhibit a biphilic character, allowing them to interact with transition metals by both donating and receiving electron density. This results in a flexible bonding arrangement that opens up numerous opportunities for cooperative reactivity6. In fact, heterobimetallic compoundsofthis kind havedemonstrated an outstandingcapacityto activate particularly inert bonds, exemplified by the cleavage of the highly robust N–H bonds in ammonia. While achieving such activation remains a challenge for transition metal complexes7–9, recent breakthroughs have been made under mild conditions for Ni/Si10 and Ir/Ge11 pairs (Fig. 1). In addition, an outer sphere cleavage of the N–H bond in ammonia upon coordination to a Ni/Ge system has also been recently disclosed12. Despite these successes, the transition of these cooperative designs from stoichiometric bond activation to catalytic regimes has been notably restricted13–16. We hypothesize that the limited number of catalytic applications is partly attributed to the coordinatively saturated environments prevailing at the two active sites in most systems (as those in Fig. 1, top). In the same vein, base-stabilized tetrylene fragments are typically employed for enhanced stability17–20,albeitat the expense of quenching their biphilic nature and, consequently, their true potential for bimetallic cooperation. At contrast, in an effort to access particularly low-coordinate complexes, our prior work combined [(ArMes2) 2 Ge:] (ArMes2 =C 6 H 3 −2,6-(C 6 H 2 −2,4,6-Me 3 ) 2 ) and[RhCl(COD)] 2 (COD = 1,5-cyclooctadiene)21. Albeit the rhodium site did not retain any ligand apart from the germylene, the resulting system featured this metal strongly embraced by two lateral aryl rings of the terphenyl substituents. While active in reversible and cooperative Received: 13 May 2024 Accepted: 25 October 2024 Check for updates Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain. e-mail: [email protected];[email protected] Nature Communications | (2024) 15:9656 1 1234567890():,; 1234567890():,; C–H bond cleavage reactions,both rhodium and germanium exhibited coordinative saturation, restricting its catalytic capacity, though we could unveil their activity towards semi-hydrogenation reactions of alkynes22. In pursuit of a genuinely low-coordinate system with enhanced reactivity (Fig. 1, bottom), our focus has now shifted to a lowcoordinate platinum(0) complex bearing our sterically congested terphenyl phosphine PMe 2 ArDipp2 (ArDipp2 =C 6 H 3 −2,6-(C 6 H 3 −2,6-iPr 2 ) 2 ), andalabiletert-butylethyleneligand23.Tomitigatethe excessivesteric protection previously provided by [(ArMes 2 ) 2 Ge:], we have chosen the mono-terphenyl germylene dimer [ArDipp2GeCl] 2 24.Inthisstudy,we investigate the stoichiometric reactivity of this low-coordinate system towards dihydrogen, water, methanol, ammonia, and acetylenes. Furthermore, we explore its potential as a catalyst in the dehalogenation of alkyl, aryl, and main group halides—an important transformation in the realms of environmental remediation, organic synthetic methodology, and isotopic labeling25. Results Synthesis and characterization of low-coordinate Pt(0)/Ge(II) compound The low-coordinate Pt(0) compound [(PMe 2 ArDipp2)Pt(TBE)] (TBE = tert-butyl ethylene) readily reacts with germylene dimer [ArDipp2GeCl] 2 in benzene to yield an intense red solution due to quantitative formation of compound 1(Fig. 2a). This highly reduced species is characterized by a 31P{1H} NMR resonance at 17.9ppm, mildly shifted from its precursor (δ23.7 ppm), and flanked by 197Pt satellites that account ●Very low-coordination ●E–H bond activation H2H2OMeOH NH 3RCCH ●Catalytically active Fig. 1 | Transition metal/heavier tetryelene cooperative reactivity. [Top] Previous examples of stoichiometric ammonia N–H bond activation across transition metal(TM)-heavier tetrylene(HT) bonds of relevance for the present contribution. [Bottom] This work: Low-coordinate Pt(0)-germylene complex active in stoichiometric bond activation and hydrodehalogenation catalysis (iPr = isopropyl; tBu =tertbutyl). (a) (b) Fig. 2 | A low coordinate platinum-germylene. a Synthesis of platinum(0)-ger- mylene compound 1by the reaction of [(PMe 2 ArDipp2)Pt(TBE)] and [ArDipp2GeCl] 2 . bMajor deformation densities from EDA-NOCV analysis of 1(0.002 a.u. isovalue). NOCV 1 and 3 show electron flow from the Pt fragment to the germylene (red to blue lobes). NOCV 2 corresponds to σdonation from the germylene to the Pt fragment. Calculations at the ZORA-BP86-D3BJ/TZVP//PCM-BP86-D3BJ/def2-SVP level of theory. Electron density flow from red to blue regions. (NOCV = Natural Orbital for Chemical Valence). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 2 for a remarkable 1J PPt coupling constant of 5376 Hz (c.f. 4414 Hz in the precursor). We attribute this pronounced increase in 1J PPt to an enhanced s-character of the Pt–P bond as the olefinisreleased—evidenced by 1H NMR signals at 4.84, 4.93, and 5.80ppm due to free TBE. Inspection of 1H NMR spectrum indicates free rotation of the terphenyl groups at both the phosphine and the germylene. Not surprisingly, compound 1is highly unstable and all attempts to isolate it in pure form from its reaction solution or to obtain single crystals for further characterization were unfruitful. Nevertheless, its nature was confirmed by subsequent reactivity studies, and its bonding rationalized by computational means. The DFT minimized geometry of 1(PCM-BP86-D3BJ/def2-SVP; see Supplementary Data 1 and also section 6 of the Supplementary Information) features a distorted T-shaped coordination around the Pt atom with a P—Pt—Ge angle of ca. 117°, and a Pt—Ge distance of 2.31 Å, considerably shorter than the sum of the covalent radii of the elements (2.56 Å). Structurally, this is reminiscent of the T-shaped geometries adopted by NiE (E= Ge, Sn) complexes recently described by Hadlington, which were attributed to the Z-type nature of the tetrylenes as ligands12. Inspection of the frontier orbitals shows that the LUMO and LUMO+ 1 are localized on the germanium atom (Fig. S47). This suggests that the germanium atom retains its electrophilic character, and is thus susceptible to react with nucleophiles, consistent with the studies discussed later. Further insights into the orbital interaction by EDA-NOCV analyses26–28 (ZORA-BP86-D3BJ/TZVP//PCMBP86-D3BJ/def2-SVP) on the previous geometry using singlet ArDipp2ClGe and Pt(PMe 2 ArDipp) fragments reveal three major interactions, which account for ca. 80% of the orbital interaction, E orb (Fig. 2b). The first and third interactions in terms of energy (41.9 and 11.3% of E orb ) correspond to π-back donation Pt to Ge, whereas σ donation from Ge to Pt comes second (26.6% E orb ), with an overall transfer of 0.13 electrons from the Pt fragment to the germylene (Hirshfeld). Reactivity studies and mechanistic investigations Next, we examined the reactivity of 1towards the activation of E–H bonds(E =H, N, O) in dihydrogen, water, methanol, and ammonia. The reactions proceeded immediately even at 25 °C, as evinced by a rapid vanish of the intense red color upon substrate addition to cleanly yield compounds 2, 3, 4, and 5through cooperative activation of H 2 ,H 2 O, MeOH, and NH 3 , respectively (Fig. 3). The electrophilic tetrel site binds a hydride, hydroxide, methoxide or amido group, whereas the additional hydride is located at the platinum center. It is important to note that the presence of the two active sites is essential for bond activation. Thus, precursor [(PMe 2 ArDipp2)Pt(TBE)] is inert towards dihydrogen, water, methanol, or ammonia. The germylene dimer does not react with dihydrogen either, although it reacts with water, methanol, and ammonia. However, as clearly evinced by 1H NMR, these reactions led to intractable mixtures of numerous terphenyl-containing species that could not be identified. Subsequent addition of [(PMe 2 ArDipp2)Pt(TBE)] to these reaction mixtures only revealed very minor formation (ca. 5–10%) of 3, 4, and 5. This contrasts with the clean reactivity of complex 1, discarding the possibility of Pt/Ge dissociation from 1followed by mononuclear reactivity and subsequent fragment coupling. Therefore, this clearly speaks in favor of the notable capacity of the low-coordinate compound 1to efficiently enable cooperative bond activation events. We observed an intense decrease of the 1J PPt coupling constant (2t,2671;3,2125;4, 2233; 5, 2429 Hz) after bond activation, diagnostic of formal bimetallic oxidative addition to yield Pt(II)-germyl compounds. The germanium hydride, only present in compound 2,ledto characteristic 1HNMRsignalsat3.50(2t:dd,3J HP =30.7,3J HH =5.2Hz) and 5.90 ppm (2c: dd, 3J HP =10.9, 3J HH = 2.3 Hz). Besides, all species exhibit a distinctive 1H-NMR resonance due to the formation of a Pt–hydride, intensively low-shifted in the case of compounds 2t (−15.7 ppm) and 5(−18.05 ppm), and more moderately for 2c (−5.6 ppm), 3(−7.45 ppm) and 4(−6.1ppm). This difference in chemical shifts correlates well with their corresponding coupling pattern. Hence, the hydride resonances of compounds 2t and 5showcases very small coupling to phosphorus (2J HP =5.2 (2t), 16 (5) Hz) and large coupling to platinum (1J HPt =1608(2t), 1092 Hz (5)). In stark contrast, the signal due to the Pt–Hof3is characterized by 2J HP =180 and 1J HPt = 297 Hz, and similar couplings are recorded for 2c and 4. These differences are clearly informative and suggest the generation of two distinct isomers for 3/4versus 5, while the activation of H 2 yields the two species, 2t and 2c,inca. 4 to 1 ratio. The prevalent one (2t) shares structure with 5,whilethe minorone(2c)fits with 3and 4. Clearly, the aforesaid values of 2J HP indicate that for the latter the phosphine and germyl fragments are in cis-disposition, while a P/Ge trans arrangement corresponds to 2t and 5. We further investigated the exchange between isomers 2t and 2c by two-dimensional exchange NMR spectroscopy (EXSY) within the temperature range Pt P iPr iPr Dipp Ge ArDipp Cl H H H2(0.5 bar) 2t trans-isomer iPr iPr P Pt Ge Cl Dipp iPr iPr iPr iPr 1 Dipp iPr iPr P Pt Ge ArDipp Cl OH H C6D6, 25 ºC < 5 min H2O(5 equiv) Pt P iPr iPr Dipp Ge ArDipp Cl NH2 H NH3(0.5 bar) C6D6, 25 ºC, < 5min 35 Dipp iPr iPr P Pt Ge ArDipp Cl OMe H 4 MeOH (1 equiv) Dipp iPr iPr P Pt Ge ArDipp Cl H H 2c cis-isomer + (4 : 1) Fig. 3 | Reactivity studies with 1. Cooperative stoichiometric reactivity of compound 1towards E–H (E = H, O, N) bonds of dihydrogen, water, methanol, and ammonia (iPr = isopropyl; Dipp = 2,6-(C 6 H 3 −2,6-iPr 2 ) 2 ;Ar Dipp2 =C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 3 between 25 and 65°C. An analysis of the recorded data led to a ΔH‡of 13.4 kcal/mol and a negative entropic parameter ΔS‡of −17.7 cal/mol K, which corresponds to an overall barrier ΔG 298 ‡of 18.6 kcal/mol (Fig. S36). The cis/trans conformations proposed above were corroborated by X-ray diffraction studies. We could grow single crystals from slow diffusion of pentane into a saturated benzene solution of 3(Fig. 4). However, all our attempts to obtain crystals of good quality for the dihydrogen activation products 2failed, leading to highly disordered structures from where we could not extract a reliable molecular model. To circumvent this limitation, we decided to synthesize a Pt(0)/Ge(II) analog breaking the pseudo-symmetry around the platinum center. To do so we prepared the same Pt(0) precursor based on the related PMe 2 ArTripp2 phosphine (ArTripp2 =C 6 H 3 -2,6-(C 6 H 3 -2,4,6-iPr 3 ) 2 )and reacted it with [ArDipp2GeCl] 2 . The resulting analogous compound 1* equally reacted with dihydrogen leading to a rather similar spectroscopic signature (see section 2 of the SupplementaryInformation) but, in this case, allowing us to grow single crystals of good quality of transisomer in 2t* (Fig. 4). Compound 2t* exhibits a pseudo-square planar coordination, being the phosphine and germyl fragments in trans-disposition with a distorted angle of 165.37(3)°. The Pt–hydride could be located at the difference electron density Fourier map with a d Pt-H of 1.51(6) Å. Opposite to that hydride, coordination is completed by a weak κ1 interaction Pt···C Arene interaction defined by a Pt–C7 distance of 2.370(3) Å that compensates the low saturation atthe metal. The other hydride ligand resides on the germanium center and could also be located (d Ge-H = 1.38(4) Å). As anticipated from NMR analysis, the conformation is completely different for compound 3,whichalso presents a pseudo-square planar coordination. However, the phosphine and germyl ligands are now in cis-arrangement (P–Pt–Ge 97.66(2)°). A hydride ligand is located at an almost ideal transdisposition (P–Pt–H of 177(1)°), with a similar d Pt-H of 1.58(3)Å comparedto2t*. Coordination in 3iscompletedbya κ2interaction withthe flanking aryl ring (Pt–C7, 2.305(2) and Pt–C8, 2.595(3) Å). The mechanisms of these E—H activations were investigated computationally by DFT methods (PCM-ZORA-B3PW91-D3BJ/def2- TZVP + SARC-ZORA-TZVP(Pt)//PCM-BP86-D3BJ/def2-SVP). The results of the calculations, summarized in Fig. 5, reveal two fundamentally different routes, one shared by the activations ofH 2 OandNH 3 ,andthe second exclusive for H 2 splitting. The former begins with initial coordination of water or ammonia to Ge, in agreement with the germylene fragmentretaining itselectrophilicnaturein1despitethedoublebond character of the Pt = Ge bond (see above). This is followed by E—H activation at the Pt—Ge bond, TS a , with barriers of 17.0 kcal mol−1for Fig. 4 | X-ray diffraction studies of bond activation products. ORTEPs of complexes 2t* and 3. Most hydrogen atoms (except those deriving from H 2 or H 2 O) are excluded and iso-propyl groups are represented in wireframe format for clarity. Thermal ellipsoids are set at 50% probability. ΔG kcal mol-1 0.0 1+ E-H 1·H2 15.9 TSa 16.6 Int1 3.3 TSm 17.8 TSisom 12.2 2t -10.6 2c -8.0 1·OH2 13.9 3t -9.7 TSa 21.8 5 4.0 3 -11.1 1·NH3 1.4 TSa 17.0 TSisom 9.0 E=OH,NH 2 1,2-sh Fig. 5 | Computational studies of bond activation processes. Calculated energy profiles for the activation of E—H bonds by 1. Magenta, cyan, and orange (dashed) traces correspond to H 2 ,NH 3, and H 2 O activations, respectively. Calculations performed at the DFT PCM-ZORA-B3PW91-D3BJ/def2-TZVP + SARC-ZORA- TZVP(Pt)//PCM-BP86-D3BJ/def2-SVP level of theory. (iPr = isopropyl; Dipp = 2,6- (C 6 H 3 -2,6-iPr 2 ) 2 ;Ar Dipp =C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ; TS = transition state). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 4 H 2 O and 21.8 kcal mol−1for NH 3 . We also considered the potential involvement of up to three water molecules in the activation of H 2 O, however, the energy barriers are at best slightly higher than the reported above for one H 2 O molecule (see Fig. S51). These barriers are higher for activations in which the forming Pt···H bond is trans to P (27.7 and 33.8 kcalmol−1for the water and ammonia systems respectively), which lead to cis isomers of 3and 5. Thus, while formation of the experimentally observed isomer 5is accounted for by the activation depicted in Fig. 5(5is the kinetic and thermodynamic isomer), formation of 3requires isomerization of the kinetic isomer, 3t (Ge trans to P), TS isom , through a barrier of ca. 20 kcal mol−1. We calculated simplified models of the cis and trans isomers of 3and 5by replacing the diisopropyl fragments by H and the terphenyl substituent on the Ge by phenyl and in both cases, the cis isomer resulted the most stable by ca. 4 kcal mol−1, suggesting a role for subtle steric effects in the relative stability of the isomers in the real systems. As such, we performed conformational analysis with extended tight-binding methods in addition to DFT optimizations to obtain relative energies that are consistent with the experiments29. In turn, activation of H 2 requires initial coordination of H 2 to Pt and oxidative addition at the transition metal, TS a , which has a barrier of 16.6 kcal mol−1,andyieldsaPt II dihydride, Int1 that readily undergoes 1,2-shift via TS m (ΔG‡=14.5kcalmol −1) to yield 2t in equilibrium with 2c through a barrier of ca 20kcal mol−1(TS isom ), in agreement with the EXSY experiments. Alternatively, H 2 activation across the Pt— Ge bond was discarded as it has barriers well in excess of 25 kcalmol−1, taking place without the previous formation of the corresponding 1·H 2 adduct (the coordination of H 2 to Ge is not a minimum in the potential energy surface). Oxidative addition reactions over low-valent main group elements represent the archetypalexample of transition metal-like reactivity for P-block elements30. However, these reactions lead to highly stable oxidized species that rarely exhibit reversible behavior towards reductive elimination31 and thus the possibility to participate in redox catalytic cycles. From the computational energetic profiles depicted in Fig. 5it can be deduced that, for the current system, regeneration of the reduced Pt(0)/Ge(II) compound 1could be plausible, as the overall energies for the forward bimetallic reductive elimination processes lie intheapproximate rangeof26–28 kcal/mol. With this aim, we exposed compounds 2, 3, and 5to dynamic vacuum at variable temperature, but their instability precluded any definitive conclusion. We could, however, demonstrate that these compounds can be interconverted. Consequently, the addition of water (5 equiv) or ammonia (0.5 bar) to compounds 2leads to the respective formation of the oxidative addition products 3and 5in around 99% spectroscopic yield (Fig. 6a). In turn, compound 3does not react with dihydrogen even under mild heating (60 °C), but it converts into the hydrido-amido complex 5 under ammonia atmosphere (Fig. 6a). The latter compound cannot, instead, be converted under the presence of neither H 2 or water, since decomposition to complex mixtures takes place during attempts to remove ammonia. Besides, we attempted the reaction of these oxidized compounds with ethylene. Once more, the hydride-amido species 5did not show any reactivity at room temperature and it decomposed under heating at 80 °C. At variance, dihydride 2and the hydride-hydroxo compound 3reacted with ethylene (0.5bar) leading to the cleavage of the Pt‒Ge bond and the formation of the previously reported compound [(PMe 2 ArDipp2)Pt(C 2 H 4 ) 2 ](6)23 along with other unidentified germanium species (Fig. 6b). These reactions further evince the synergistic action of platinum and germanium, here through hydride migration from the former to the latter. Interestingly, exposure of precursor 1to ethylene under the same experimental conditions did not produce any trace of bis-ethylene 6. Instead, it led to a new species characterized by a 31P{1H} resonance at 6.0 ppm exhibiting a large 1J PPt coupling of 4052 Hz that suggests no change in the oxidation state of platinum. That species gives back precursor 1upon removal of ethylene atmosphere. Based on these data we attribute speculate the new compound to be an ethylene adduct of 1in which the weak π-arene interaction is substituted by ethylene. Nonetheless, the lability of the coordinated ethylene is evinced, for instance, by reaction with water, which readily produces the hydride-hydroxo compound 3. To complete our stoichiometric studies, we tested the reactivity with acetylene and phenylacetylene, which offered a contrasting outcome to the reaction with ethylene. In this case, 1H NMRanalysis points out to the incorporation of two molecules of the alkynes per Pt/Ge core, which readily yield compounds 7(Fig. 7) with rapid fading of the intense red color of 1. These species are characterized by 31P{1H} resonances at 18.6 (7a,C 2 H 2 ) and 13.5 (7b,PhCCH),flanked by 197Pt satellites of 2180 and 2184 Hz, respectively. These reduced values of 1J PPt compared to 1indicate that the platinum center has been oxidized to Pt(II), which together with the absence of any distinctive hydridic resonance by 1H NMR, suggest a double 1,2-addition of the Pt/Ge core across the alkynes. Three 1H NMR resonances at 8.2 and 5.8 ppm for Pt Ge H H2 Pt Ge OH H3 Pt Ge NH2 H5 Pt Ge H H2 H2O NH3 Pt Ge NH2 H5 Pt Ge OH H3 NH3 X X X H2 H2 H2O Pt Ge (a) Pt Ge H H2 Pt Ge OH H3 (b) 1 C2H4 C2H4 C2H4 [P]Pt 6 [P]Pt 6 + + Pt Ge Cl ArDipp 1-C2H4 [P] other Ge species other Ge species Fig. 6 | Stoichiometric reactivity studies for mechanistic investigations. aInterconversion reactions between compounds 2,3,and5and; (b) reactivity studies of compounds 1,2,and3with ethylene (most ligands have been omitted for clarity). Fig. 7 | Reactivity of 1 towards alkynes. Reaction of compound 1with alkynes towards 1,2-platinogermacyclobutadiene compounds 7, including ORTEP of bwheremost hydrogen atoms are excluded and 2,6-aryl groups are represented in wireframe format for clarity. Thermal ellipsoids are set at 50% probability. (iPr = isopropyl; Dipp = 2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ;Ar Dipp =C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 5 one proton each and at 5.46 ppm for two protons in compound 7a,and a single two-proton peak at 6.6 ppm for 7b, are attributed to the newly formed diene fragment. The structure of 7b was further authenticated by X-ray diffraction studies from crystals grown from pentane diffusion into its saturated benzene solution, confirming a 1,2-platinogermacyclobutadiene formulation (Fig. 7).ThedistancebetweenPtandGeaccountsfor3.4Å average, reflectingthedisappearanceofthePt–Ge bond, while the C–C bond distances of the activated alkynes are of around 1.33 Å, in agreement with a diene formulation. The fluxional character of the stabilizing π-arene contact between a lateral aryl ring of the terphenyl phosphine and the unsaturated platinum center is reflected by two close but different Pt–C ipso distances of 2.570(9) and 2.673(9) Å for the two independent molecules of 7b present in the unit cell. The formation of these compounds resemble the reactivity of frustrated Lewis pairs (FLPs) with alkynes32, where 1,2-addition products are common, including those in Pt-based FLPs reported by our group33.Theinsertion of alkynes into transition metal-germyl compounds is also known34, while the reaction of digermynes with alkynes to produce digermanium cyclobutadiene structures has been reported before35,36.However, their transition metal-containing versions, namely 1,2- metalagermacyclobutadienes as the ones described herein, have been suggested as catalytic intermediates, but their transient nature had to date prevented isolation37,38. At variance, the highly congested environment of the present system confers sufficient stability, allowing for their full characterization. Catalytic hydro dehalogenation The above reactivity studies clearly demonstrate the capacity of 1to cooperatively activate strong bonds. We next wondered whether this could translate into catalytic regimes, aided by its low coordination and thus its ability to bind additional substrates to be transformed. Recent studies from the group of Bourissou revealed that cooperation between an electron-rich Pd(0) and a bound electrophilic borane enabled the catalytic hydrodechlorination of aryl chlorides towards arenes39. This kind of Pd/borane synergism is reminiscent of the multisite cooperation operating in compound 1,andthuswedeemedof interest to explore its catalytic potential in hydro dehalogenation reactions. We were further encouraged by studies from the Lloret group, where more challenging C(sp3)–Clbondsinalkylchlorides were cleaved within a catalytic cycle for reductive cyclizations using, once more, a cooperative bimetallic system (Co/Ni) with the key feature of a nucleophilic low-valent metal40. Before discussing our own findings, it is worth noting that most catalytic dehalogenation studies have focused on aryl halides, while alkyl halides with stronger C(sp3)–X bonds remain less investigated, and in many cases, catalysts that efficiently dehalogenate aromatic substrates fail to convert aliphatic versions41. Moreover, homogeneous catalysts that hydrodehalogenate alkyl halides have mostly covered bromide substrates42,43,showing little success with chloride counterparts44. On these grounds, we decided to examine 1as a catalyst for the dehalogenation of aliphatic halides, using 1-bromo-2,2-dimethylpro- pane as a benchmark substrate (Table 1). We use dihydrogen as a convenient source of hydride since we already demonstrated that it readily forms dihydride 2as a potential active species.Basic conditions are naturally required to quench the release of acid. Using 10 mol% catalyst loading, we reach full and clean conversion towards 2,2- dimethylpropane using LiHMDS (HMDS = [N(SiMe 3 ) 2 ]− )asthebaseand benzeneassolventafterheatingat80°Cforfourhours(entry4).The activity of the platinum precursor was considerably reduced (38%, entry 9), evincing the positive partnership between platinum and germanium, while there was no activity for germylene or in the absence of catalyst. Alternatively, we realized that debromination took place at moderate yields even at room temperature under irradiation with blue light (440 nm; see section 5 of the Supplementary Information for details). We then examined the scope under thermal conditions with a series of aliphatic and aromatic halides (Table 2). Chlorides, bromides, and iodides could be dehalogenated, but the system revealed no catalytic activity for hydrodefluorination. To complete these studies, we also tested some representative examples of E–Cl bonds (E = B, Si, Sn, P). Notsurprisingly,higherconversions arereachedforalkylbromides, followed by iodides and chlorides. Hydrodehalogenation reactions proceed in good yields for unsubstituted alkyl halides. 1,2-diha- loethanes are cleanly converted to ethane without any trace of monodechlorination, while chloroalkyl ethers were quantitatively dechlorinated. Using 4-(chloromethyl)styrene complete conversion was accomplished, leading to an ca. 1:1 mixture of dechlorination (4- methylstyrene) and dechlorination/hydrogenation (1-ethyl-4-methyl- bencene) products. For aryl halides we run the reactions at 100 °C since we noticed lower conversions. Good yields were obtained for most substrates, having electron donating and withdrawing groups or particularly bulky substituents. The catalyst showed remarkable functional group tolerance, including amine, nitrile, and even nitro groups, though it exhibits no reactivity in the presence of a carboxylic or boronic acids, which we attribute to their intrinsic reactivity with the base. We also tested some representative heterocycles, which were dehalogenated with variable outcomes, achieving full conversion for 2-chloropyridine. Finally, we attempted the dechlorination of illustrative examples of E–Cl bonds (E = B, Si, Sn, P). Although chlorocatecholborane was not altered, trimethylsilyl chloride, trimethyltin chloride, and di-tertbutylchlorophosphine were dechlorinated. Table 1 | Optimizing conditions for hydro debromination with 1 EntryaCatbSolvent Base ConditionscYield (%)d 12C 6 D 6 NaOtBu Δ26 22C 6 D 6 DABCO Δ0 32C 6 D 6 Cs 2 CO 3 Δ0 42C 6 D 6 LiHMDS Δ>99 52C 6 D 6 NEt 3 Δ0 62C 6 D 6 NH 3 Δ0 72C 6 D 6 -Δtrace 8-C 6 D 6 LiHMDS Δ0 9[Pt]C 6 D 6 LiHMDS Δ38 10 [Ge] C 6 D 6 LiHMDS Δ0 11 2CD 2 Cl 2 LiHMDS Δ0 12 2thf-d 8 LiHMDS Δ37 13 2Tol-d 8 LiHMDS Δ47 14 2C 6 D 6 LiHMDS hυ58 15 - C 6 D 6 LiHMDS hυ0 16 [Pt] C 6 D 6 LiHMDS hυ10 17 [Ge] C 6 D 6 LiHMDS hυ0 aCatalytic runs were performed in J. Young NMR tubes with RBr (0.054 mmol), catalyst (0.0054 mmol), base (0.054 mmol), H 2 (1 bar), and solvent (500 μL). bPt/Ge catalyst 2was generated in situ by 2:1 mixture of [(PMe 2 ArDipp2)Pt(TBE)] and [ArDipp2GeCl] 2 . Abbreviations [Pt] and [Ge] refer to the later precursors. cTwo sets of conditions were used: ‘Δ’(80 °C) and ‘hυ‘(irradiation 400 nm, 25 °C). dYield was calculated by 1HNMRusingC 6 Me 6 (4.4 mg) as internal standard. Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 6 We next conducted preliminary investigations on the dehalogenation mechanism, at first by performing some additional stoichiometric reactions. Precursor 1does not react with neopentyl bromide or LiHMDS under catalytically relevant conditions, while it readily adds H 2 to form 2, as discussed above. In turn, dihydride 2is inert towards the aforesaid bromide (80 °C). In contrast, it rapidly reacts with LiHMDS, though in the absence of other substrates, it evolves into a unidentifiable mixture of products. Nonetheless, 1H NMR analysis evinces the absence of low-frequency hydridic resonances upon base addition (as also observed during NMR monitoring of catalytic reactions). Based on these findings, we propose a mechanism starting with the hydrogenation of 1by H 2 to form 2t, which undergoes deprotonation at Pt to yield an anionic species, A−(Fig. 8). Then, we conducted DFT calculations on the chemical system comprising 2t,neopentyl bromide (NpBr) as the substrate, and HMDS-as the base (see Fig. S57 for details). Our studies suggest that intermediate A−reacts with the substrate via a S N 2-type transition state involving nucleophilic attack by the platinum atom to the CH 2 Br carbon of NpBr to form B·Br−,a species featuringaneutralmetalliccomplexwithaneopentylligandon the platinum atom and one hydride on the germanium atom. Bromide elimination may then follow in the form of LiBr. Finally, reductive elimination (RE) to yield the reaction product and regenerate 1takes place from C, a species resulting from 1,2-shift at B(reminiscent of the same step in the mechanism for H 2 activation by 1), which can be described as a square planar complex with one neopentyl and one hydride ligand coordinated in a cis fashion to a formal Pt(II) ion, further stabilized by one phosphine and one germylene. The rate-limiting step of the cycle is the S N 2-type reaction of A− with NpBr, for which we have calculated an energy barrier of Table 2 | Scope of hydrodehalogenationa,b aCatalytic runs were performed in J.Young NMR tubes with RX (0.054 mmol), 2(prepared in situ; 0.0054 mmol), LiHMDS (0.054 mmol), H 2 (1 bar) and C 6 D 6 (500 μL) at 80 °C (substrates a, c, and d) or 100 °C (substrates b) for 4 h. bOverall conversion calculated by 1H NMR using hexamethylbenzene (4.4 mg) as internal standard. Values in brackets refer to selectivity to the hydrodehalogenation product, or ratios ofmonovs bisdehalogenation. cIsobutene as side-product. dDiphenylethane as side-product. e1-ethyl-4-methylbencene as side-product. fMono vs bisdehalogenation. gtBu 2 P–PtBu 2 as side-product. Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 7 29.2 kcalmol−1, consistent with the catalysis not taking place at room temperature and requiring several hours to complete. Nonetheless, we cannot yet completely rule out other potential alternative pathways, including radical routes, as some hints point to their potential involvement: the hydrodebromination of benzyl bromide led to an around 1:1 ratio of ethylbenzene and the homocoupling product 1,2-dipheny- lethane, while the homocoupling product (tBu 2 P–PtBu 2 )wasdetected using tBu 2 PCl as substrate45. Nonetheless, a more thorough mechanistic picture, including open-shell systems, lies out of the scope of the present contribution and will be reported in due course. In summary, we provide a method to access a low coordinate platinum(0)-germylene complex based on the kinetic stabilization provided by bulky terphenyl substituents. This exotic design revealed remarkable capacity for cooperative bond activation under rather mild conditions. Stoichiometric reactions with dihydrogen, water, methanol, and ammonia demonstrated E–H bond cleavage (E = H, N, O) via two distinct cooperative pathways that were elucidated by computational means. In turn, reaction with alkynes led to rare 1,2-platino- germacyclobutadienes, which were earlier proposed as catalytic intermediates, but never isolated. The low-coordination environment allows for facile isomerization events, and indeed two distinct isomeric forms defined by the cis/trans disposition of the germyl and phosphine across the platinum center were disclosed and characterized by spectroscopicmeans andX-raydiffractionstudies.Weforeseethatthis flexibility will be of relevance for the application of this and other related low-coordinate cooperative systems in catalysis. Indeed, we already investigated its catalytic potential in the hydrodehalogenation of aliphatic and aromatic halides under thermal and photochemical conditions. Under mild dihydrogen pressure (1 bar), good conversions and selectivity were recorded even for inert alkyl chlorides. The proposed mechanism involves the active participation of the two active sites, which underscore the potential of still underdeveloped systems that partner low-valent transition and main group metals in particularly low-coordination environments, a research avenue that we are currently pursuing in our laboratories. Methods General considerations All preparations and manipulations were performed by using standard Schlenk and glovebox techniques, under an atmosphere of argon and of high purity nitrogen, respectively. All solvents were dried, stored over 4 Å molecular sieves, and degassed prior to use. Toluene (C 7 H 8 ), THF (C 4 H 8 O), and n-pentane (C 5 H 12 ) were distilled under nitrogen over sodium. [D 8 ]-THF and C 6 D 6 weredriedoversodium and distilledunder argon. All other reagents were used as received from commercial suppliers. Solution NMR spectra were recorded with Bruker AVANCE NEO-300, AVANCE NEO-400, AVANCE III-400, and AVANCE NEO-500 spectrometers. Spectra were referenced to external SiMe 4 (δ: 0 ppm) by using the residual proton solvent peaks as internal standards (1H NMR experiments), or the characteristic resonances of the solvent nuclei (13CNMRexperiments),while31P was referenced to H 3 PO 4 .The 1Hand13C signals were assigned by means of 2D HSQC and HMBC experiments. The X-ray diffraction structural characterization of compounds 2t*, 3, and 7a is collected in Supplementary Data 2, Supplementary Data 3, and Supplementary Data 4, respectively. Synthesis of new compounds The synthesis and spectroscopic characterization of compounds 1, 2t, 3, 5, and 7a is described herein, while details of other compounds and precursors are described in the Supplementary Information. Compound 1. In the Glovebox, a J-Young NMR tube was loaded with [ArDipp2GeCl] 2 (16 mg, 0.016 mmol) and [(PMe 2 ArDipp2)Pt(TBE)] (24 mg, 0.032mmol). Then the solids were solubilized in 0.5mL of C 6 D 6 to yield an intense red solution of compound 1(>99% NMR yield). Attempts to isolate it from the reaction mixture, even at larger scales, proved unsuccessful due to high instability. 1H NMR (400 MHz, C 6 D 6 , Fig. 8 | Proposed catalytic cycle. Proposed mechanism for the hydrodehalogenation of NpBr catalyzed by 1based on experimental and computational investigations. Calculations performed at the DFT PCM-ZORA-B3PW91-D3BJ/def2- TZVP + SARC-ZORA-TZVP(Pt)//PCM-BP86-D3BJ/def2-SVP level of theory. (iPr = isopropyl; Dipp = 2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ;Ar Dipp =C 6 H 3 -2,6-(C 6 H 3 -2,6-iPr 2 ) 2 ; HMDS = hexamethyldisilazane; Np = neopentyl). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 8 298 K): δ7.22–7.17 (overlapping signals, 4H, CH), 7.14–7.07 (overlapping signals, 9H, CH), 6.92–6.88 (overlapping signals, 4H, CH), 6.69 (br, 1H, CH), 3.09 (sept, J H-H =6.6Hz, 4H, CH(CH 3 ) 2 ), 2.33 (br, 4H, CH(CH 3 ) 2 ), 1.38 (d, J H-H = 6.6 Hz, 12H, CH(CH 3 ) 2 ), 1.33 (overlapping signals, 18H, CH(CH 3 ) 2 +PMe 2 ), 1.05 (d, J H-H =6.6Hz,12H,CH(CH 3 ) 2 ), 0.89 (d, J H-H =6.6Hz,12H,CH(CH 3 ) 2 ). 31P{1H} NMR (161.98 MHz, C 6 D 6 , 298 K): δ17.9 (s, 1J PPt =5376Hz). 13C{1H} NMR (100.63 MHz, C 6 D 6 , 298 K): δ160.7 (d, J C-P = 18 Hz, Cq), 147.8 (Cq), 147.3 (d, J C-P =11Hz,Cq), 143.0 (d, J C-P = 3 Hz, Cq), 141.9 (d, J C-P = 34 Hz, Cq), 137.9 (Cq), 131.6 (d, J C-P = 7 Hz, CH), 129.7 (CH), 129.2 (CH), 128.6 (d, J C-P =3Hz,CH),128.3 (CH), 128.0 (CH), 123.7 (CH), 122.5 (CH), 31.6 (br, CH(CH 3 ) 2 ), 30.8 (CH(CH 3 ) 2 ),25.8(CH(CH 3 ) 2 ), 25.2 (CH(CH 3 ) 2 ), 23.3 (CH(CH 3 ) 2 ), 22.9 (br, CH(CH 3 ) 2 ), 19.9 (d, J C-P =28Hz, PMe 2 ). Compound 2t and 2c.Inthe Glovebox, a J-Young NMR tube was loaded with [ArDipp2GeCl] 2 (16 mg, 0.016 mmol) and [(PMe 2 ArDipp2)Pt(TBE)] (24 mg, 0.032 mmol). Then the solids were solubilized in 0.5 mL of C 6 D 6 , freeze-pumped to remove the nitrogen gas, and filled with 0.5 barof H 2 , which resulted in immediate vanish of the intense red color towards a pale-yellow solution of a mixture of two isomers of complex 2(73% 2t and 27% 2c; NMR spectroscopic yield). Signals for 2t:1H NMR (400 MHz, C 6 D 6 , 298 K): δ7.28 (t, J H-H = 7.5Hz, 2H, CH), 7.24-7.20 (overlapping signals, 7H,CH),7.13–7.11 (overlapping signals, 4H, CH), 6.97 (d, J H-H = 7.5 Hz, 1H, CH), 6.88 (t, J H-H =7.5Hz,1H,CH),6.80(m,2H,CH),6.41(m,1H,CH), 3.50 (dd, J H-P =30.7,J H-H = 5.2 Hz, 1H, Ge-H), 3.21 (sept, J H-H =6.7Hz,2H, CH(CH 3 ) 2 ), 3.10 (sept, J H-H = 6.7 Hz, 1H, CH(CH 3 ) 2 ), 2.96 (sept, J H-H = 6.7 Hz, 1H, CH(CH 3 ) 2 ), 2.35 (m, 2H, CH(CH 3 ) 2 ), 2.12 (sept, J H-H = 6.7 Hz, 1H, CH(CH 3 ) 2 ), 1.47 (overlapping signals, 6H, CH(CH 3 ) 2 (3H) + PMe 2 (3H)), 1.42-1.33 (m, 21H, CH(CH 3 ) 2 (18H) + PMe 2 (3H)), 1.12–1.08 (overlapping signals, 15H, CH(CH 3 ) 2 ), 0.80 (overlapping signals, 12H, CH(CH 3 ) 2 ), −15.7 (t, J H-P =5.2,J H-H = 5.2, J H-Pt =1608Hz,1H,Pt- H). 31P{1H} NMR (161.98 MHz, C 6 D 6 ,298K):δ21.9 (s, 1J PPt =2671Hz). 13C{1H} NMR (100.63 MHz, C 6 D 6 ,298K):δ149.4 (Cq), 147.6 (Cq), 147.5 (Cq), 147.0 (d, J C-P = 12 Hz, Cq), 146.7 (Cq), 146.4 (Cq), 146.2 (Cq), 142.9 (Cq), 141.0 (Cq), 140.5 (d, J C-P =13Hz,Cq),136.7(d,J C-P = 7 Hz, Cq), 132.2 (CH), 132.1 (CH), 132.0 (CH), 130.3 (CH), 130.2 (CH), 129.7 (CH), 129.4 (CH), 129.2 (CH), 129.1 (CH), 128.7 (CH), 128.4 (CH), 127.0 (CH), 126.4 (CH), 126.2 (CH), 125.3 (CH), 124.5 (CH), 123.0 (CH), 122.8 (CH), 122.7 (CH), 122.6 (CH), 122.4 (CH), 122.2 (CH), 122.1 (CH), 122.0 (CH), 31.6 (CH(CH 3 ) 2 ), 31.0 (CH(CH 3 ) 2 ), 30.9 (CH(CH 3 ) 2 ), 30.7 (CH(CH 3 ) 2 ), 30.6 (CH(CH 3 ) 2 ), 30.5 (CH(CH 3 ) 2 ), 25.7 (CH(CH 3 ) 2 ), 25.6 (CH(CH 3 ) 2 ), 25.5 (CH(CH 3 ) 2 ), 25.4 (CH(CH 3 ) 2 ), 25.2 (CH(CH 3 ) 2 ), 24.0 (CH(CH 3 ) 2 ), 23.8 (CH(CH 3 ) 2 ), 23.4 (CH(CH 3 ) 2 ), 23.2 (CH(CH 3 ) 2 ), 21.1 (CH(CH 3 ) 2 ), 17.5 (d, J C-P =12Hz,PMe 2 ), 16.7(d, J C-P = 13 Hz, PMe 2 ). Selected signals for 2c:1H NMR (400 MHz, C 6 D 6 ,298K):5.90(dd,J H-P =10.9,J H-H = 2.3 Hz, 1H, Ge- H), −5.6 (d, J H-P = 178.0, J H-Pt = 341.6 Hz, 1H, Pt-H). 31P{1H} NMR (161.98 MHz, C 6 D 6 ,298K):δ25.6 (s). Compound 3. In the Glovebox, a J-Young NMR tube was loaded with [ArDipp2GeCl] 2 (16 mg, 0.016 mmol) and [(PMe 2 ArDipp2)Pt(TBE)] (24 mg, 0.032 mmol). Then the solids were solubilized in 0.5 mL of C 6 D 6 yielding an intense red solution of 1.Then 5 equivalents of H 2 Owereadded(3µL, 0.16 mmol) leading to a paleyellow solution of the complex 3(>99% NMR yield). A small crop of suitable crystals for X-ray analysis was grown from slow diffusion of pentane into its benzene solution (4 mg, 11%). 1H NMR (400 MHz, C 6 D 6 , 298 K): δ7.31 (d, J H-H = 7.6 Hz, 1H, CH), 7.25–7.22 (m, 3H, CH), 7.20-7.18 (m, 3H, CH), 7.16-7.14 (br, 2H, CH), 7.12–7.10 (m, 2H, CH), 7.05-7.02 (m, 2H, CH), 6.99 (dd, J H-H = 7.6, J H-H = 3.2 Hz, 2H, CH), 6.87 (d, J H-H =7.6Hz, 1H,CH),6.80(td,J H-H =7.6Hz,J H-P = 2.2, 1H), 6.72 (t, J H-H =7.6Hz,1H, CH), 6.36 (brd, J H-H = 7.6 Hz, 1H, CH), 3.26 (sept, J H-H = 6.7 Hz, 4H, CH(CH 3 ) 2 ), 3.02 (sept, J H-H =6.7Hz, 4H, CH(CH 3 ) 2 ), 2.36 (m, 4H, CH(CH 3 ) 2 ), 1.67 (d, J H-P =5.3Hz, 3H, PMe 2 ), 1.64 (d, J H-P = 5.3 Hz, 3H, PMe 2 ), 1.45 (d, J H-H = 6.7 Hz, 9H, CH(CH 3 ) 2 ), 1.35 (d, J H-H = 6.7 Hz, 6H, CH(CH 3 ) 2 ), 1.07 (d, J H-H =6.7Hz,12H,CH(CH 3 ) 2 ), 1.02 (d, J H-H =6.7Hz, 3H, CH(CH 3 ) 2 ), 1.00 (d, J H-H = 6.7 Hz, 3H, CH(CH 3 ) 2 ), 0.98 (d, J H-H = 6.7 Hz, 3H, CH(CH 3 ) 2 ), 0.85 (d, J H-H =6.7Hz,3H,CH(CH 3 ) 2 ), 0.81 (d, J H-H = 6.7 Hz, 3H, CH(CH 3 ) 2 ), 0.80 (d, J H-H = 6.7 Hz, 3H, CH(CH 3 ) 2 ), 0.77 (d, J H-H = 6.7 Hz, 3H, CH(CH 3 ) 2 ), −7.45 (d, J H-P = 180, J H-Pt =297Hz, 1H, Pt-H). 31P{1H} NMR (161.98 MHz, C 6 D 6 ,298K):δ29.6 (1J PPt =2125Hz).13C{1H} NMR (100.63 MHz, C 6 D 6 ,298K):δ147.4 (Cq), 147.1 (Cq), 146.8 (Cq), 146.7 (Cq), 146.5 (Cq), 145.8 (d, J C-P =13Hz,Cq), 145.6 (Cq), 144.0 (Cq), 143.0 (Cq), 140.9 (d, J C-P = 34 Hz, Cq), 139.7 (Cq), 138.3 (Cq), 137 (d, J C-P = 7 Hz, Cq), 132.2 (CH), 131.5 (CH), 131.4 (CH), 131.3 (CH), 129.9 (CH), 129.7 (CH), 129.5 (CH), 129.1 (CH), 129.0 (CH), 128.6 (d, J C-P = 6 Hz, CH), 126.8 (CH), 125.5 (CH), 123.0 (CH), 122.9 (CH), 122.8 (CH), 122.7 (CH), 122.5 (CH), 30.9 (CH(CH 3 ) 2 ), 30.8 (CH(CH 3 ) 2 ), 30.7 (CH(CH 3 ) 2 ), 26.0 (CH(CH 3 ) 2 ), 25.8 (CH(CH 3 ) 2 ), 25.5 (CH(CH 3 ) 2 ), 25.4 (CH(CH 3 ) 2 ), 25.3 (CH(CH 3 ) 2 ), 24.1 (CH(CH 3 ) 2 ), 24.0 (CH(CH 3 ) 2 ), 23.4 (CH(CH 3 ) 2 ), 22.3 (CH(CH 3 ) 2 ), 15.5 (d, J C-P =27Hz, PMe 2 ), 15.2 (d, J C-P =27Hz,PMe 2 ). Compound 5. In the Glovebox, a J-Young NMR tube was loaded with [ArDipp2GeCl] 2 (16 mg, 0.016 mmol) and [(PMe 2 ArDipp2) Pt(TBE)] (24 mg, 0.032mmol). Then the solids were solubilized in 0.5 mL of C 6 D 6 , freeze-pumped to remove the argon gas, and filled with 0.5 bar of NH 3 . The intense red color rapidly vanished to form a pale-yellow solution of complex 5(around 95%spectroscopic yield). 1H NMR (400 MHz, C 6 D 6 ,298K):δ7.20–7.13 (overlapping signals, 7H, CH), 7.11–7.09 (overlapping signals, 5H, CH), 7.05 (t, J H-H = 7.2 Hz, 4H, CH), 6.98–6.92 (overlapping signals, 3H, CH), 3.25 (sept, J H-H = 6.7 Hz, 1H, CH(CH 3 ) 2 ), 3.18 (sept, J H-H = 6.7 Hz, 2H, CH(CH 3 ) 2 ), 2.94 (m, 1H, CH(CH 3 ) 2 ), 2.83 (sept, J H-H = 6.7 Hz, 2H, CH(CH 3 ) 2 ), 2.74 (sept, J H-H = 6.7 Hz, 2H, CH(CH 3 ) 2 ), 1.48 (m, 12H, CH(CH 3 ) 2 ), 1.38 (d, J H-H = 6.7 Hz, 6H, CH(CH 3 ) 2 ), 1.27 (d, J H-H = 6.7 Hz, 6H, CH(CH 3 ) 2 ), 1.14–1.06 (overlapping signals, 1H, CH(CH 3 ) 2 (6H) + PMe 2 (6H)), 1.01–0.98 (overlapping signals, 6H, CH(CH 3 ) 2 ), 0.87–0.83 (overlapping signals, 12H, CH(CH 3 ) 2 ), −18.06 (d, J H-P =16, J H-Pt =1092Hz, 1H, Pt-H) 31P{1H} NMR (161.98 MHz, C 6 D 6 ,298K):δ−11.2 (1J PPt =2429Hz).13C{1H} NMR (100.63 MHz, C 6 D 6 ,298K):δ148.1 (Cq), 148.0 (Cq), 147.5 (Cq), 147.0 (d, J C-P = 25 Hz, Cq), 146.6 (Cq), 145.1 (Cq), 143.2 (d, J C-P =8Hz, Cq), 142.2 (Cq), 140.0 (Cq), 132.9 (d, J C-P = 7 Hz, CH), 130.3 (CH), 130.0 (CH), 126.7 (CH), 126.2 (CH), 123.5 (CH), 123.0 (CH), 122.7 (CH), 122.6 (CH), 121.9 (CH), 31.2 (CH(CH 3 ) 2 ), 31.0 (CH(CH 3 ) 2 ), 30.9 (CH(CH 3 ) 2 ), 30.7 (CH(CH 3 ) 2 ), 25.6 (CH(CH 3 ) 2 ), 25.5 (CH(CH 3 ) 2 ), 25.3 (CH(CH 3 ) 2 ), 23.9 (CH(CH 3 ) 2 ), 23.7 (CH(CH 3 ) 2 ), 23.2 (CH(CH 3 ) 2 ), 22.4 (CH(CH 3 ) 2 ), 14.0 (d, J C-P =15Hz,PMe 2 ), 13.8 (d, J C-P =9Hz,PMe 2 ). Compound 7b.In the Glovebox, a J-Young NMR tube was loaded with [ArDipp2GeCl] 2 (16 mg, 0.016 mmol) and [(PMe 2 ArDipp2)Pt(TBE)] (24 mg, 0.032 mmol). Then the solids were solubilized in 0.5 mL of C 6 D 6 yielding an intense red solution of 1. Then 2 equivalents of phenylacetylene were added (8 µL, 0.064 mmol) leading toa pale-yellow solution of the complex7b, which formed in around 95% spectroscopic yield. A small crop of suitable crystals for X-ray analysis was grown from slow diffusion of pentane into its benzene solution (5 mg, 11%). 1H NMR (400 MHz, C 6 D 6 , 298 K): δ7.47 (t, J H-H = 7.7Hz, 2H, CH), 7.40 (br, 2H, CH), 7.27 (br d, J H-H = 7.1 Hz, 6H, CH), 7.20−7.15 (overlapping signals, 6H, CH), 7.09 (t, J H-H =7.1Hz,3H,CH),7.03–6.95 (overlapping signals, 3H, CH), 6.89 (br d, J H-H = 7.1Hz, 5H, CH), 6.76 (t, J H-H = 7.7 Hz, 1H, CH), 6.60 (br, 2H, PhC=CH), 3.12 (sept, J H-H =6.6Hz, 2H, CH(CH 3 ) 2 ), 2.98 (m, 2H, CH(CH 3 ) 2 ), 2.64 (sept, J H-H = 6.6 Hz, 2H, CH(CH 3 ) 2 ), 2.54 (m, 2H, CH(CH 3 ) 2 ), 1.56 (d, J H-H = 6.6 Hz, 6H, CH(CH 3 ) 2 ), 1.37−1.27 (overlapping signals, 12H, CH(CH 3 ) 2 ), 1.16 (br, 9H, CH(CH 3 ) 2 ), 1.02 (br, 12H, CH(CH 3 ) 2 ), 0.84 (overlapping signals, 6H, CH(CH 3 ) 2 (3H) + PMe 2 (3H)), 0.68 (br, 6H, CH(CH 3 ) 2 ), 0.57 (d, J H-P = 7.8Hz, 3H, PMe 2 ). 31P{1H} NMR (161.98 MHz, C 6 D 6 ,298K):δ13.5 (1J PPt =2184Hz). 13C{1H} NMR (100.63 MHz, C 6 D 6 ,298K):δ148.3 (Cq), 147.7 (d, J C-P =18Hz,Cq), 147.0 (Cq), 146.4 (Cq), 146.4 (Cq), 144.9 (d, J C-P = 14 Hz, Cq), 141.5 (Cq), 140.4 (Cq), 139.0 (d, J C-P = 37 Hz, Cq), 132.5 (d, J C-P =7Hz, PhC=CH), 132.0 (CH), 130.4 (CH), 129.6 (CH), 128.4 (CH), 128.2 (CH), 126.3 (CH), 122.7 (CH), 125.0 (CH), 123.4 (CH), 123.0 (CH), 122.9 (CH), 31.6 (CH(CH 3 ) 2 ), 31.3 (CH(CH 3 ) 2 ), 30.8 (CH(CH 3 ) 2 ), 30.6 (CH(CH 3 ) 2 ), 25.8 (CH(CH 3 ) 2 ), 25.7 (CH(CH 3 ) 2 ), 25.5 (CH(CH 3 ) 2 ), 25.1 (CH(CH 3 ) 2 ), 23.4 (CH(CH 3 ) 2 ), 22.7 (CH(CH 3 ) 2 ), 22.3 (CH(CH 3 ) 2 ), 13.9 (d, J C-P =8Hz,PMe 2 ). Article https://doi.org/10.1038/s41467-024-53940-9 Nature Communications | (2024) 15:9656 9