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Experimental and computational investigation on the formation pathway of [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) from [RuCl2(CO)3]2 and ERR′

Taimisto, Marjaana,Bajorek, Tom,Rautiainen, J. Mikko,Pakkanen, Tapani A.,Oilunkaniemi, Raija,Laitinen, Risto S.

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This is a sel -a chi ed e sion o an o iginal a icle. This e sion may di e om he o iginal in pagina ion and ypog aphic de ails. Au ho (s): Ti le: Yea : Ve sion: Copy igh : Righ s: Righ s u l: Please ci e he o iginal e sion: CC BY 4.0 h ps://c ea i ecommons.o g/licenses/by/4.0/ Expe imen al and compu a ional in es iga ion on he o ma ion pa hway o [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) om [RuCl2(CO)3]2 and ERR′ © The Royal Socie y o Chemis y 2022 Published e sion Taimis o, Ma jaana; Bajo ek, Tom; Rau iainen, J. Mikko; Pakkanen, Tapani A.; Oilunkaniemi, Raija; Lai inen, Ris o S. Taimis o, M., Bajo ek, T., Rau iainen, J. M., Pakkanen, T. A., Oilunkaniemi, R., & Lai inen, R. S. (2022). Expe imen al and compu a ional in es iga ion on he o ma ion pa hway o [RuCl2(CO)2(ERR′)2] (E = S, Se, Te; R, R′ = Me, Ph) om [RuCl2(CO)3]2 and ERR′. Dal on T ansac ions, 51(31), 11747-11757. h ps://doi.o g/10.1039/D2DT02018A 2022 Dal on T ansac ions PAPER Ci e his: DOI: 10.1039/d2d 02018a Recei ed 25 h June 2022, Accep ed 12 h July 2022 DOI: 10.1039/d2d 02018a sc.li/dal on Expe imen al and compu a ional in es iga ion on he o ma ion pa hway o [RuCl 2 (CO) 2 (ERR’) 2 ] (E = S, Se, Te; R, R’= Me, Ph) om [RuCl 2 (CO) 3 ] 2 and ERR’† Ma jaana Taimis o, a Tom Bajo ek,‡ a J. Mikko Rau iainen, b Tapani A. Pakkanen, a Raija Oilunkaniemi * a and Ris o S. Lai inen * a The pa hways o he o ma ion o he se ies o [RuCl 2 (CO) 2 (ERR’) 2 ] (E = S, Se, Te; R, R’= Me, Ph) com- plexes om [RuCl 2 (CO) 3 ] 2 and ERR’ha e been explo ed expe imen ally in THF and CH 2 Cl 2 , and compu a- ionally by PBE0-D3/de 2-TZVP calcula ions. The end-p oduc s and some eac ion in e media es ha e been isola ed and iden ified by NMR spec oscopy, and hei c ys al s uc u es ha e been de e mined by X- ay diff ac ion. The ela i e s abili ies o he [RuCl 2 (CO) 2 (ERR’) 2 ] isome s ollow he o de cc >ccc > cc > ≈c c ( he e ms c/ e e o cis/ ans a angemen o he ligands in he o de o Cl, CO, and ERR’). The yields we e a he simila in bo h sol en s, bu he eac ions we e significan ly as e in THF han in CH 2 Cl 2 . The highes yields we e obse ed o he ellu oe he complexes, and he yields dec eased wi h ligh e chalcogenoe he s. PBE0-D3/de 2-TZVP calcula ions indica ed ha he eac ion pa h is indepen- den o he na u e o he sol en . The subs i u ion o one CO ligand o he in e media e [RuCl 2 (CO) 3 (ERR’)] by he second ERR’shows he highes ac i a ion ba ie and is he a e-de e mining s ep in all eac ions. The obse ed as e eac ion a e in THF han in CH 2 Cl 2 upon eflux can he e o e be explained by he highe boiling poin o THF. A oom empe a u e he eac ions in bo h sol en s p oceed equally slowly. When he eac ion is ca ied ou in THF, he o ma ion o [RuCl 2 (CO) 3 (THF)] is also obse ed, and he eac ion may p oceed wi h he subs i u ion o THF by ERR’. The o ma ion o he THF complex, howe e , is no necessa y o he dissocia ion o he [RuCl 2 (CO) 3 ] 2 . The mal ene gy a oom empe a u e is sufficien o clea e one o he b idging Ru–Cl bonds. The in e media e hus o med unde - goes a acile eac ion wi h ERR’. This mechanism is iable also in non-coo dina ing CH 2 Cl 2 . In oduc ion Ca bon monoxide eleasing molecules (CORMs) ha e u ned ou o be impo an in sa e applica ions o CO in he apeu ics. Sui able molecules include o ganome allic complexes, alde- hydes, cyclic dike ones, and ca boxylic acids, among o he s ( o some selec ed examples o ecen e iews, see e . 1). While [RuCl 2 (CO) 3 ] 2 (CORM-2) is a use ul ca bon monoxide eleasing compound, i is also a con enien eagen in he p epa a ion o mononuclea complexes o u henium ( o he syn heses and s uc u al cha ac e iza ion o selec ed com- plexes wi h diffe en non-me allic dono a oms du ing he pas en yea s, see e . 2). The main p oduc s in hese eac ions wi h monoden a e ligands a e [RuCl 2 (CO) 3 L] 2a,c,e,g,h and [RuCl 2 (CO) 2 L 2 ] 2a–c,g,l (see Cha 1). The ac-isome is mos common o [RuCl 2 (CO) 3 L], as exem- pli ied by he ecen X- ay s uc u al de e mina ions, 2c,g,h and also indica ed by NMR spec oscopy. 2a,c,e,g,h In case o [RuCl 2 (CO) 2 L 2 ], he cc isome s a e p edominan , 2a,b,g,l hough he cc-isome has also been epo ed. 2c In case o polyden a e chela ing ligands, he ac ual isome depends on he s e eoche- mical equi emen s by he ligand. 2d, ,i,j The o ma ion o [RuCl 2 (CO) 3 L] and [RuCl 2 (CO) 2 L 2 ] is gen- e ally hough o be sequen ial wi h he ini ial in e ac ion be ween he incoming ligand and he u henium cen e leading o he symme ic clea age o he b idging chlo ido ligands 3 (see Scheme 1). The second pa o he eac ion is he †Elec onic supplemen a y in o ma ion (ESI) a ailable: Syn he ic de ails, c ys al s uc u e de e mina ions o 2 cc ,4 cc ,6 cc ,8 cc ,10, and 11, en a i e molecula s uc u e o 8 cc , assignmen o NMR spec a, compu a ional esul s. CCDC 2152613–2152617 and 2152619. Fo ESI and c ys allog aphic da a in CIF o o he elec onic o ma see DOI: h ps://doi.o g/10.1039/d2d 02018a ‡P esen add ess: Nu iAg L d, 62 A ow Rd To on o, ON, M9M 2L8 Canada. a Labo a o y o Ino ganic Chemis y, En i onmen al and Chemical Enginee ing, Uni e si y o Oulu, P.O. Box 3000, 90014 Oulu, Finland. E-mail: [email p o ec ed] b Depa men o Chemis y and Nanoscience Cen e , Uni e si y o Jy äskylä, P.O. Box 35, 40014 Jy äskylä, Finland This jou nal is © The Royal Socie y o Chemis y 2022 Dal on T ans. Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online View Jou nal subs i u ion o CO by he incoming ligand in he mononuclea complexes hus o med. The coo dina ion o a sol en molecule Sol o [RuCl 2 (CO) 3 ] 2 has been sugges ed o be an ini ial s ep in he eac ion esul ing in he o ma ion o mononuclea ac- [RuCl 2 (CO) 3 (Sol )]. The ligand subs i u ion o Sol by he incoming ligand L leads o ac-[RuCl 2 (CO) 3 L]. The subs i u ion o CO by he second ligand affo ds he inal p oduc (see Scheme 1). This is exempli ied by he eac ions o [RuCl 2 (CO) 3 ] 2 wi h bipy idine ligands in diffe en sol en s. 3 While his app oach is logical and is gene ally accep ed, he e is no di ec expe imen al o compu a ional e idence ha he ligand subs i u ion in [RuCl 2 (CO) 3 ] 2 eally ollows his pa hway. The cu en con ibu ion add esses his issue by explo ing he eac ion o [RuCl 2 (CO) 3 ] 2 wi h chalcogenoe he s ERR′(E = S, Se, Te; R, R′= Me, Ph). Mononuclea chalcogenoe he complexes o u henium ha e long been known ( o ea ly li e a u e, see e iews in e . 4). Du ing he las h ee decades hese complexes ha e a ac ed mo e a en ion, which is cen e ed on he ligand chemis y o seleno- and ellu oe he s in addi ion o hioe he s ( o mo e ecen e iews, see e . 5). Hiebe and John 6 explo ed al eady in 1970s he isome ism o [RuCl 2 (CO) 2 (ERR′) 2 ](E=S, Se, Te; R, R′= a numbe o alkyl o a yl g oups) by eco ding he dipole momen s, IR spec a, and 1 H NMR spec a o he complexes o med in diffe en eac ions. John 6b in e ed ha he main isome in each complex is he cc (see Cha 1). The la e c ys al s uc u e de e mina ions o [RuCl 2 (CO) 2 (SPh 2 ) 2 ], 7 [RuCl 2 (CO) 2 (TePh 2 ) 2 ], 8 and [RuCl 2 (CO) 2 {Te(CH 2 SiMe 3 ) 2 } 2 ] 9 ha e con i med ha in he solid s a e, all h ee complexes indeed exis as cc -isome s. As pa o ou pu sui o explo e he o ma ion mechanism o [RuCl 2 (CO) 2 L 2 ] complexes we ha e in es iga ed in his con- ibu ion he o ma ion, s e eochemis y, and isome ism o [RuCl 2 (CO) 2 (ERR′) 2 ] (E = S, Se, Te; R, R′= Me, Ph) complexes (see Table 1). We epo he c ys al s uc u es o 2 cc ,4 cc , and 6 cc , as well as he isola ion and cha ac e iza ion o [RuCl 2 (CO) 3 (SeMe 2 )] (10) and [RuCl 2 (CO) 3 (SeMePh)] (11) com- plexes ha a e po en ial in e media e p oduc s along he eac- ion pa h. The eac ion pa hway has been explo ed by PBE0- D3/de 2-TZVP calcula ions. Expe imen al Gene al The syn heses o SeMePh and TeMePh we e ca ied ou unde an ine a mosphe e by using Schlenk echniques. The eac- ions wi h [RuCl 2 (CO) 3 ] 2 we e ca ied ou in ai . [RuCl 2 (CO) 3 ] 2 Cha 1 Possible isome s o [RuCl 2 (CO) 3 L], [RuCl 2 (CO) 2 L 2 ], and [RuCl 2 (CO)L 3 ]. The no a ion o he isome s o [RuCl 2 (CO) 2 L 2 ]: cc = cis(Cl), cis(CO), ans(L); ccc =cis(Cl), cis(CO), cis(L); c c =cis(Cl), ans(CO), cis(L); = ans(Cl), ans(CO), ans(L); cc = ans(Cl), cis(CO), cis(L). Scheme 1 Fo ma ion o ac-[RuCl 2 (CO) 3 L] and cc -[RuCl 2 (CO) 2 L 2 ] om [RuCl 2 (CO) 3 ] 2 . Table 1 The designa ion o he [RuCl 2 (CO) 2 (ERR’) 2 ] (E = S, Se, Te; R, R’= Me, Ph) isome s (see Cha 1) [RuCl 2 (CO) 2 (SMe 2 ) 2 ]1 cc ,1 ccc ,1 cc ,1 ,1 c c [RuCl 2 (CO) 2 (SMePh) 2 ]2 cc ,2 ccc ,2 cc ,2 ,2 c c [RuCl 2 (CO) 2 (SPh 2 ) 2 ]3 cc ,3 ccc ,3 cc ,3 ,3 c c [RuCl 2 (CO) 2 (SeMe 2 ) 2 ]4 cc ,4 ccc ,4 cc ,4 ,4 c c [RuCl 2 (CO) 2 (SeMePh) 2 ]5 cc ,5 ccc ,5 cc ,5 ,5 c c [RuCl 2 (CO) 2 (SePh 2 ) 2 ]6 cc ,6 ccc ,6 cc ,6 ,6 c c [RuCl 2 (CO) 2 (TeMe 2 ) 2 ]7 cc ,7 ccc ,7 cc ,7 ,7 c c [RuCl 2 (CO) 2 (TeMePh) 2 ]8 cc ,8 ccc ,8 cc ,8 ,8 c c [RuCl 2 (CO) 2 (TePh 2 ) 2 ]9 cc ,9 ccc ,9 cc ,9 ,9 c c Pape Dal on T ansac ions Dal on T ans. This jou nal is © The Royal Socie y o Chemis y 2022 Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online (Johnson Ma hey), Te 2 Ph 2 (Ald ich), Se 2 Ph 2 (Ald ich), SMePh (Fluka Chemicals), me hyl iodide (Bake ), SeMe 2 (Fluka Chemicals), NaBH 4 (Me ck), and n-hexane (Kebolab) we e used as pu chased. Te ahyd o u an (Lab-Scan) and die hyl e he (Lab-Scan) we e d ied o e Na/benzophenone and dichlo o- me hane (Lab-Scan) o e P 4 O 10 . Me hanol (Fishe Sci. In . Co) was deoxygena ed wi h a gon p io o use. NMR spec oscopy The 13 C{ 1 H}, 77 Se, and 125 Te NMR spec a we e eco ded a oom empe a u e on a B uke DPX 400 spec ome e ope a - ing a 100.61, 76.31, and 126.24 MHz, espec i ely. The espec - i e spec al wid hs we e 25.06–26.04, 30.18–53.33, and 37.88–63.49 kHz. The pulse wid h was 4.0 μs o 13 C, 6.7 μs o 77 Se, and 10.0 μs o 125 Te. The 13 C{ 1 H} NMR spec a we e e e enced o he sol en esonance and a e epo ed ela i e o Me 4 Si. Sa u a ed solu ions o SeO 2 (aq) and H 6 TeO 6 (aq) we e used as ex e nal s anda ds o 77 Se and 125 Te chemical shi s. Chemical shi s (ppm) a e epo ed ela i e o nea SeMe 2 and TeMe 2 [δ(SeMe 2 )=δ(SeO 2 ) + 1302.6 ( e . 10) and δ(TeMe 2 )= δ(H 6 TeO 6 ) + 710.9 ( e . 11)]. X- ay diff ac ion Diff ac ion da a o 2 cc ,4 cc ,6 cc ,10, and 11 we e collec ed on a B uke Nonius Kappa-CCD diff ac ome e using g aphi e monoch oma ed MoK α adia ion (λ= 0.71073 Å; 55 kV, 25 mA). C ys al da a and he de ails o he s uc u e de e mina ions a e gi en in Table S1 in ESI.† S uc u es we e sol ed by di ec me hods using SHELXS-2016 and e ined using SHELXL-2016. 12 A e he ull- ma ix leas -squa es e inemen o he non-hyd ogen a oms wi h aniso opic he mal pa ame e s, he hyd ogen a oms we e placed in calcula ed posi ions in he a oma ic ings (C–H = 0.95 Å) and in he CH 3 g oups (C–H = 0.98 Å). The sca e ing ac o s o he neu al a oms we e hose inco po a ed wi h he p og ams. Quali y o he ob ained c ys als o 8 cc enabled only an app oxima e e inemen o he s uc u e. The e inemen equi ed cons aining he he mal pa ame e s o all ca bon a oms o be equal. This complex and he app oxima e me ical da a o bond pa ame e s a e shown in ESI (Fig. S1†), since he accu acy o he c ys al s uc u e de e mina ion was sufficien o he iden i ica ion o he species and he e o e allowed he unambiguous assignmen o he 125 Te NMR esonance. P epa a ion o SeMePh and TeMePh Diphenyl diselenide o di ellu ide (0.507 g, 1.64 mmol and 0.658 g, 1.61 mmol, espec i ely) was dissol ed in 25 mL o THF, and a solu ion o NaBH 4 in MeOH was added d opwise a 0 °C un il he solu ion u ned colou less. Me hyl iodide (0.200 mL, 3.20 mmol) was added, and he solu ion was s i ed a oom empe a u e o wo hou s. The eac ion mix u e was pou ed in o wa e and ex ac ed wi h die hyl e he in se e al po ions. The combined o ganic laye s we e d ied on MgSO 4 . E apo a ion o he sol en affo ded SeMePh as a ligh - yellow oil (0.454 g, yield 83%) and TeMePh as a yellow oil (0.471 g, yield 67%). SeMePh: NMR (δ, ppm) (CDCl 3 ): 13 C{ 1 H} 6.7 (s, CH 3 ), 125.8, 128.9, 129.9, 131.9; 77 Se 197 (c . li . 197 ( e . 13)). TeMePh: NMR (δ, ppm) (CDCl 3 ): 13 C{ 1 H} −17.2 (s, CH 3 ), 112.3, 126.9, 129.0, 136.3; 125 Te 328 (c . li . 329 ( e . 14)). Gene al p ocedu e o he p epa a ion o [RuCl 2 (CO) 2 (ERR′) 2 ] (E = S, Se, Te; R, R′= Me, Ph) A ypical syn hesis was ca ied ou by dissol ing ERR′(E = S, Se, Te; R, R′= Me, Ph) in 5 mL o CH 2 Cl 2 o THF and adding he esul ing solu ion d opwise o a suspension o [RuCl 2 (CO) 3 ] 2 in 15 mL o he same sol en . The mix u e was e luxed un il a clea solu ion was ob ained ( ypical imes we e 50–100 h in CH 2 Cl 2 and 5–10 h in THF). The solu ion was e apo a ed o hal o he o iginal olume and hexane was added. The p ecipi a e was sepa a ed by il a ion and e-c ys allized om CH 2 Cl 2 / hexane a +3 °C. In some eac ions, wo c ops o c ys als we e o med. They we e manually sepa a ed unde he mic oscope. The quan i a i e in o ma ion o he syn heses, as well as he assignmen o he NMR spec a and he iden i ica ion o he complexes a e gi en in sec ions 1 and 4 in ESI.† Compu a ional de ails All s uc u es we e op imized using Gaussian 16 p og am package, 15 PBE0 DFT unc ional, 16 and de 2-TZVP 17 basis se s. Implici C-PCM sol en model was applied o ea he sol- a ion effec s, 18 and G imme’s empi ical co ec ion wi h Becke–Johnson damping o model he dispe sion o ces. 19 All calcula ed minimum s uc u es we e s a iona y poin s on he po en ial su ace ee o imagina y equencies and all an- si ion s a e s uc u es ha e one imagina y equency co es- ponding o he eac ion coo dina e hey a e desc ibing. The op imized Ca esian coo dina es o he a oms in all compu ed species a e gi en in sec ion 5.4 in ESI.† Resul s and discussion Fo ma ion o [RuCl 2 (CO) 2 (ERR′) 2 ] (E = S, Se, Te; R, R′= Me, Ph) In o ganic sol en s, [RuCl 2 (CO) 3 ] 2 eac s wi h o ganic mono- chalcogenides o o m [RuCl 2 (CO) 2 (ERR′) 2 ] (eqn (1)). RuCl2ðCOÞ3  2ðsÞþ4ERR′sol ðÞ !2 RuCl2ðCOÞ2ðERR′Þ2  sol ðÞþ2COðgÞð1Þ The syn heses we e ca ied ou by e luxing in CH 2 Cl 2 o THF. Though he p oduc s and hei yields we e a he simila in bo h sol en s, he eac ion seemed o be as e in THF han in CH 2 Cl 2 . The e was a clea end obse ed o he yields o he complexes, as he chalcogen elemen became hea ie . In case o [RuCl 2 (CO) 2 (SRR′) 2 ] he yields we e 10–30%, [RuCl 2 (CO) 2 (SeRR′) 2 ] showed yields o 30–40%, and [RuCl 2 (CO) 2 (TeRR′) 2 ] we e o med a good yields o ca. 80%. Molecula s uc u es [RuCl 2 (CO) 2 (ERR′) 2 ] (E = S, Se, Te; R, R′= Me, Ph). The c ys al s uc u es o [RuCl 2 (CO) 2 (SPh 2 ) 2 ](3 cc ), 7 Dal on T ansac ions Pape This jou nal is © The Royal Socie y o Chemis y 2022 Dal on T ans. Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online [RuCl 2 (CO) 2 (TePh 2 ) 2 ]·1 2C 6 H 6 (9 cc ) 8 and [RuCl 2 (CO) 2 {Te (CH 2 SiMe 3 ) 2 } 2 ] 9 ha e been de e mined p e iously and ha e shown ha in each case he complex is a cc -isome in acco d- ance wi h he ini ial sugges ion by John 6b (see Cha 1). In his con ibu ion we epo he c ys al s uc u es o [RuCl 2 (CO) 2 (SMePh) 2 ](2 cc ), [RuCl 2 (CO) 2 (SeMe 2 ) 2 ](4 cc ), and [RuCl 2 (CO) 2 (SePh 2 ) 2 ](6 cc ). Spec oscopic iden i ica ion o [RuCl 2 (CO) 2 (SeMePh) 2 ](5 cc ), and he en a i e s uc u al cha ac e iza ion o [RuCl 2 (CO) 2 (TeMePh) 2 ](8 cc ) also enabled he iden i ica ion o he molecula species (see sec ions 3 and 4 in ESI†). I can be seen om Fig. 1 ha all de e mined complexes a e expec edly oc ahed al cc -isome s in line wi h he p e- iously epo ed s uc u es. 7–9 The selec ed bond pa ame e s o he diffe en cc -[RuCl 2 (CO) 2 (ERR′) 2 ] complexes a e com- pa ed in Table S2 in ESI.† The Ru–S, Ru–Se, and Ru–Te bond leng hs span anges o 2.3774(12)–2.4084(11), 2.4908(7)–2.5125(7), and 2.6478(7)– 2.6637(7) Å, espec i ely. The Ru–S and Ru–Se bonds appea o be sligh ly longe han he espec i e sums o co alen adii o 2.28 and 2.41 Å, 20 bu he Ru–Te bond leng hs a e nea o he single bonds ( he sum o he co alen adii is 2.61 Å ( e . 20)). In e es ingly, he wo Ru–E (E = S, Se, Te) bonds in each complex a e ben away om he egion o wo Ru–CO bonds [ he E–Ru–E bond angles ange 164.01(3)–174.11(4)°; see Table S2 in ESI†]. Geome ies o all [RuCl 2 (CO) 2 (ERR′) 2 ] isome s we e op i- mized using he PBE0-D3/de 2-TZVP me hod and he op i- mized s uc u es a e summa ized in Table S5 in ESI.†The ela- i e ene gies o he isome s diffe signi ican ly, as shown in Fig. 2. The s abili y o de ing is cc >ccc > cc > ≈c c. These indings a e consis en wi h he spec oscopic in e - ence ha he cc -isome is he main isome o he [RuCl 2 (CO) 2 (ERR′) 2 ] complexes. 6b I is suppo ed by he ela i e ene gies o he diffe en isome s shown in Fig. 2. The ccc- isome s a e he nex ene gy- a ou able species in all com- plexes, bu e en hei ela i e ene gies a e 13–27 kJ mol −1 abo e hose o he cc -isome s. All o he isome s show signi i- can ly highe ela i e ene gies. I is in e es ing ha e en hough bulky ligands in mu ually cis posi ions a e expec ed o expe ience signi ican s e ic epulsion, his does no appea o be a se ious p oblem e en in he case o EPh 2 , as can be con- cluded om he ela i e ene gies shown in Fig. 2 and by he simila i y o he bond pa ame e s in ques ion (see Table S5 in ESI†). The ela i e s eng hs o he ans-in luence o he ligands seem o play he main ole in he s abili y end. The ans-in luence ollows he end: CO > ERR′> Cl. When he ca bonyl g oups a e in he mu ual ans posi ions o each o he , he Ru–C bond is signi ican ly weake han when hey a e mu ually in cis posi ions. The e o e, he - and c c- isome s lie signi ican ly highe in ene gy han he o he h ee isome s. I also seems ha he ans-in luence plays a mo e sig- ni ican ole in he ela i e leng hs o he Ru–E bonds in diffe en isome s han he s e ic effec s due o he o ganic g oups (see Table S2 in ESI†). [RuCl 2 (CO) 3 (SeRR′)] (R, R′= Me, Ph). In addi ion o cc - [RuCl 2 (CO) 2 (SeRR′) 2 ] [R, R′=Me(4 cc ); R = Me, R′=Ph(5 cc )], he eac ions o [RuCl 2 (CO) 3 ] 2 and SeMe 2 o SeMePh affo ded colou less c ys als o [RuCl 2 (CO) 3 (SeMe 2 )] (10) and [RuCl 2 (CO) 3 (SeMePh)] (11), espec i ely, wi h ca. 10–20% iso- Fig. 2 Rela i e PBE0/de 2-TZVP Gibbs ene gies (in kJ mol −1 )o [RuCl 2 (CO) 2 (ERR’) 2 ] (E = S, Se, Te; R, R’= Me, Ph). The nume ical alues o he ela i e ene gies a e shown in Table S6 in ESI.† Fig. 1 Molecula s uc u es o (a) cc -[RuCl 2 (CO) 2 (SMePh) 2 ](2 cc ), (b) cc -[RuCl 2 (CO) 2 (SeMe 2 ) 2 ](4 cc ), and (c) cc -[RuCl 2 (CO) 2 (SePh 2 ) 2 ](6 cc ). The an- iso opic displacemen pa ame e s a e gi en in 50% p obabili y le el. Hyd ogen a oms a e omi ed o cla i y. Pape Dal on T ansac ions Dal on T ans. This jou nal is © The Royal Socie y o Chemis y 2022 Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online la ed yields. Thei c ys al s uc u es a e shown in Fig. 3 and he selec ed bond pa ame e s a e lis ed in Table S4 in ESI.† The bond pa ame e s o 10 and 11 a e as expec ed. The s onge ans-in luence o selenium compa ed o ha o chlo - ine esul s in he bond leng h Ru1–C3 o be longe han hose o Ru1–C1 and Ru1–C2 [1.944(5) s. 1.895(4)–1.903(5) Å and 1.946(3) s. 1.892(3)–1.901(3) Å in 10 and 11, espec i ely]. Consequen ly, C3–O3 is somewha sho e han C1–O1 and C2–O2 in case o bo h complexes, hough he diffe ence is no s a is ically signi ican . The ou e o he eac ion o [RuCl 2 (CO) 3 ] 2 and ERR′(E = S, Se, Te; R, R′= Me, Ph) Fo ma ion o cc -[RuCl 2 (CO) 2 (ERR′) 2 ]. [RuCl 2 (CO) 3 ] 2 and ERR′(E = S, Se, Te; R, R′= Me, Ph) affo d cc - [RuCl 2 (CO) 2 (ERR′) 2 ] somewha as e in THF han in CH 2 Cl 2 . The yields, howe e , seem o be independen o he sol en . We ha e ca ied ou DFT in es iga ion o he possible eac ion pa hways a PBE0-D3/de 2-TZVP le el o heo y o explo e he ole o he sol en and sol en coo dina ion o [RuCl 2 (CO) 3 ] 2 in he eac ion. The PBE0-D3/de 2-TZVP scans o he eac ion su aces a e exempli ied by he eac ion o [RuCl 2 (CO) 3 ] 2 and EMe 2 , which a e shown in Fig. 4 o he eac ion in THF and in Fig. 5 o he eac ion in CH 2 Cl 2 . The ene ge ics o he possible pa ial eac ions and he ac i a ion ene gies in bo h sol en s a e shown in Table 2. The eac ion in THF can be conside ed o ake place ollow- ing wo diffe en ou es, which a e indica ed in Fig. 4. The ou e a, which consis s o eac ion in e media es I#a(#= he o dinal numbe along he eac ion coo dina e; 1–3) and he ansi ion s a es TS#a(#=1–4) ha a e connec ed by g een dashed lines, ep esen s he eac ion, in which he THF mole- cule i s coo dina es o one o he wo u henium cen es in [RuCl 2 (CO) 3 ] 2 leading o he clea age o he bond be ween his u henium and one b idging chlo ido ligand. The second THF molecule hen coo dina es o he neighbou ing u henium cen e and leads o he clea age o he bond be ween he emaining b idging chlo ido ligand and u henium. This esul s in he o ma ion o mononuclea [RuCl 2 (CO) 3 (THF)]. The ac i a ion ba ie s in hese wo s eps (40.2 and 32.3 kJ mol −1 o TS1a and TS2a, espec i ely; see Table 2) a e ela- i ely low, and his pa o he eac ion is expec ed o be apid e en a oom empe a u e. The hi d s ep in ol es he subs i u ion o he THF ligand by EMe 2 . I can be seen om Fig. 4 and Table 2 ha he ac i- a ion ba ie is signi ican ly highe han in he wo i s s eps (81.5, 76.1, and 63.9 kJ mol −1 o SMe 2 , SeMe 2 , and TeMe 2 , Fig. 3 The molecula s uc u es o (a) [RuCl 2 (CO) 3 (SeMe 2 )] (10) and (b) [RuCl 2 (CO) 3 (SeMePh)] (11). The aniso opic displacemen pa ame e s ha e been gi en a 50% p obabili y le el. Fig. 4 PBE0-D3/de 2-TZVP ene gy p ofiles o wo al e na i e ou es o he eac ion o [RuCl 2 (CO) 3 ] 2 and EMe 2 (E = S, Se, Te) in THF. The nume ical alues o he ene ge ics a e shown in Table 2. Dal on T ansac ions Pape This jou nal is © The Royal Socie y o Chemis y 2022 Dal on T ans. Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online Fig. 5 PBE0-D3/de 2-TZVP ene gy p ofile o he eac ion o [RuCl 2 (CO) 3 ] 2 and EMe 2 (E = S, Se, Te) in CH 2 Cl 2 . Table 2 PBE0-D3/de 2-TZVP Gibbs ene gy changes and ac i a ion ene gies o he indi idual s eps in he eac ion o [RuCl 2 (CO) 3 ] 2 and EMe 2 in THF and CH 2 Cl 2 Reac ion Gibbs ene gy (kJ mol −1 ) E=S E=Se E=Te [RuCl 2 (CO) 3 ] 2 +EMe 2 in THF a Rou e a Indi idual eac ion s eps 1 2[RuCl 2 (CO) 3 ] 2 +1 2THF ⇄1 2[Ru(THF)Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1a)ΔG(1a) 15.1 15.1 15.1 1 2[Ru(THF)Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1a)+1 2THF ⇄[RuCl 2 (CO) 3 (THF)] (I2a)ΔG(2a)−3.6 −3.6 −3.6 [RuCl 2 (CO) 3 (THF)] (I2a) + EMe 2 ⇄[RuCl 2 (CO) 3 (EMe 2 )] (I3a,b) + THF ΔG(3a)−40.8 −45.9 −60.6 [RuCl 2 (CO) 3 (EMe 2 )] (I3a,b) + EMe 2 ⇄[RuCl 2 (CO) 2 (EMe 2 ) 2 ](P)+CO ΔG(4a,b) 9.8 4.2 −15.7 T ansi ion s a es 1 2[RuCl 2 (CO) 3 ] 2 +1 2THF ⇄1 2TS1a E a (1a) 40.2 40.2 40.2 1 2[Ru(THF)Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1a) + THF ⇄1 2TS2a E a (2a) 32.3 32.3 32.3 [RuCl 2 (CO) 3 (THF)] + EMe 2 ⇄TS3a E a (3a) 81.5 76.1 63.9 [RuCl 2 (CO) 3 (EMe 2 )] + EMe 2 ⇄TS4a,b E a (4a,b) 149.6 145.2 130.2 Rou e b Indi idual eac ion s eps 1 2[RuCl 2 (CO) 3 ] 2 ⇄1 2[RuCl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1b)ΔG(1b) 33.7 33.7 33.7 1 2[RuCl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1b)+1 2EMe 2 ⇄1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2b)ΔG(2b)−41.9 −45.7 −54.7 1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2b)+1 2EMe 2 ⇄[RuCl 2 (CO) 3 (EMe 2 )] (I3a,b)ΔG(3b)−21.0 −22.3 −28.0 [RuCl 2 (CO) 3 (EMe 2 )] (I3a,b) + EMe 2 ⇄[RuCl 2 (CO) 2 (EMe 2 ) 2 ](P)+CO ΔG(4a,b) 9.7 4.2 −15.7 T ansi ion s a es 1 2[RuCl 2 (CO) 3 ] 2 ⇄1 2TS1b E a (1b) 36.4 36.4 36.4 1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2b)+1 2EMe 2 ⇄1 2TS2b E a (2b) 36.5 41.7 38.2 1 2[RuCl 2 (CO) 3 (EMe 2 )] + 1 2EMe 2 ⇄TS4a,b E a (4a,b) 149.6 145.2 130.2 [RuCl 2 (CO) 3 ] 2 +EMe 2 in CH 2 Cl 2b Indi idual eac ion s eps 1 2[RuCl 2 (CO) 3 ] 2 ⇄1 2[RuCl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1′)ΔG(1′) 33.1 33.1 33.1 1 2[RuCl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I1′)+1 2EMe 2 ⇄1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2′)ΔG(2′)−41.4 −45.2 −54.2 1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2′)+1 2EMe 2 ⇄[RuCl 2 (CO) 3 (EMe 2 )] (I3′)ΔG(3′)−21.4 −22.7 −28.4 [RuCl 2 (CO) 3 (EMe 2 )] (I3′) + EMe 2 ⇄[RuCl 2 (CO) 2 (EMe 2 ) 2 ](P)+CO ΔG(4′) 7.8 4.5 −15.3 T ansi ion s a es 1 2[RuCl 2 (CO) 3 ] 2 ⇄1 2TS1′E a (1′) 35.8 35.8 35.8 1 2[Ru(EMe 2 )Cl(CO) 3 (μ-Cl)RuCl 2 (CO) 3 ](I2′)+1 2EMe 2 ⇄1 2TS2′E a (2′) 36.6 41.2 37.6 1 2[RuCl 2 (CO) 3 (EMe 2 )] + 1 2EMe 2 ⇄TS3′E a (3′) 149.6 144.9 130.2 a See Fig. 4. b See Fig. 5. Pape Dal on T ansac ions Dal on T ans. This jou nal is © The Royal Socie y o Chemis y 2022 Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online espec i ely). In e es ingly, he [RuCl 2 (CO) 3 (EMe 2 )] complexes hus o med a e e y s able. The inal s ep leading o he o - ma ion o he end-p oduc s cc -[RuCl 2 (CO) 2 (SeMe 2 ) 2 ](P) is he subs i u ion o CO by EMe 2 . The ac i a ion ba ie s o his s ep a e he highes in case o all eac ions (149.6–130.2 kJ mol −1 , see Table 2). Rou e b( eac ion in e media es I#band he ansi ion s a es TS#b) ep esen s he eac ion pa h, in which he he mal ene gy esul s in he clea age o he b idging Ru–Cl bond wi hou coo dina ion o he sol en THF. The in e media e I1b shows a e y shallow local minimum. When EMe 2 is in o- duced, he in e media e I2b is o med wi hou an ac i a ion ba ie . I should be no ed, howe e , ha THF can also eac wi h I1b in a simila ashion o o he chalcogenides wi hou he ac i a ion ba ie , which would esul in he o ma ion o [RuCl(CO) 3 (THF)(μ-Cl)RuCl 2 (CO) 3 ], ha is iden ical o I1a (con- nec ed by a ed dashed line; see Fig. 4). A emp s o ind a ansi ion s a e o he conce ed coo di- na ion o EMe 2 and he clea age o he b idging Ru–Cl leading o he di ec o ma ion o [RuCl(CO) 3 (EMe 2 )(μ-Cl)RuCl 2 (CO) 3 ] (in e media e I2b) om [RuCl 2 (CO) 3 ] 2 esul ed in ansi ion s a es ha we e much highe in ene gy. This ende s he con- ce ed eac ion mechanism unlikely. The expe imen al suppo o he coo dina ion o he sol en o he wo u henium a oms in [RuCl 2 (CO) 3 ] 2 comes om he obse a ion ha some eac ion ba ches affo ded colou less c ys als, which we e shown by c ys al s uc u e de e mina ion o be [RuCl 2 (CO) 3 (THF)] (I2a;seeFig.4).Thes uc u eo I2a has been epo ed p e iously by G ay and Duffey. 21 The de ec ion o his complex in some eac ion ba ches indica es ha THF indeed coo dina es o [RuCl 2 (CO) 3 ] 2 , bu he o ma ion o I1a could equally well ollow ei he he ou e ao ou e b, o bo h. The addi ion o he second EMe 2 o [RuCl(CO) 3 (EMe 2 )(μ-Cl) RuCl 2 (CO) 3 ](I2b) gene a es I3b, which is iden ical o I3a. The las s ep in ol ing he subs i u ion o CO by EMe 2 yielding Pis iden ical in bo h al e na i e ou es. The compa ison o he ene ge ics in he ou es aand bin Fig. 4 and Table 2 indica es ha he he mal opening o he b idging Ru–Cl bond in [RuCl 2 (CO) 3 ] 2 is compe i i e o he ini ial coo dina ion o he sol en , and he addi ion o EMe 2 o he ee coo dina ion si e esul s in [RuCl(CO) 3 (EMe 2 )(μ-Cl) RuCl 2 (CO) 3 ] (in e media e I2b), which lies lowe in ene gy han [RuCl(CO) 3 (THF)(μ-Cl)RuCl 2 (CO) 3 ] (in e media e I1a)o [RuCl 2 (CO) 3 (THF)] (in e media e I2a). The e is a signi ican ly highe ene gy ba ie om I2a o I3a,b han om I2b o I3a,b. The las s ep in he eac ion is iden ical in bo h al e na i e pa hways and shows he highes ene gy ba ie . I is he a e- de e mining s ep o he o e all eac ion. When he eac ion is ca ied ou in CH 2 Cl 2 , he coo di- na ion o he sol en o [RuCl 2 (CO) 3 ] 2 does no ake place. The ene gy p o ile o his eac ion is shown in Fig. 5, and he PBE0-D3/de 2-TZVP ene ge ics o he indi idual eac ion s eps a e shown in Table 2. All in e media es (I1′–I3′) and he end- p oduc Pagain show local minima wi h only eal equencies, and all ansi ion s a es (TS1′–TS3′) show only one imagina y equency each along he eac ion coo dina e. I can be seen om Fig. 5 ha he eac ion p o ile in CH 2 Cl 2 is i ually iden ical wi h ha shown o he eac ion in THF wi hou sol en coo dina ion (c . ou e bin Fig. 4). The i s in e media e I1′again lies in he shallow local ene gy minimum and he in oduc ion o he i s me hyl chalcogen- ide o he unsa u a ed i e-coo dina e u henium cen e in I1′ p oceeds wi hou he ac i a ion ba ie . The addi ion o he second me hyl chalcogenide ligand p oceeds acco ding o he in e change mechanism, wi h he ac i a ion ba ie a he low and o he same o de o magni ude as in he eac ion in THF. The e o e, he clea age o he b idging Ru–Cl bonds is also expec ed o ake apidly place e en a oom empe a u e. The ac i a ion ba ie s in he inal subs i u ion s ep (CO subs i u ed by he second EMe 2 ) a e almos iden ical ega d- less o he sol en (see Table 2) and de e mine he o e all a e o he eac ion. I can be in e ed ha he main ac o in he obse ed as e eac ion a e in THF compa ed o ha in CH 2 Cl 2 is due o he highe boiling poin o THF ( he boiling poin o THF is 66 °C and ha o CH 2 Cl 2 is 40 °C). The composi ion o he diffe en eac ion mix u es has been moni o ed as a unc ion o ime by 13 C{ 1 H}, 77 Se, and 125 Te NMR spec oscopy, as app op ia e. This is exempli ied by he eac ion o SeMe 2 wi h [RuCl 2 (CO) 3 ] 2 in CH 2 Cl 2 (see Fig. 6). The isola ion and s uc u al and spec oscopic cha ac e iz- a ion o bo h [RuCl 2 (CO) 3 (SeMe 2 )] (10; 77 Se chemical shi 55 ppm) and cc -[RuCl 2 (CO) 2 (SeMe 2 ) 2 ](5 cc ; 77 Se chemical shi 88 ppm) p o ide expe imen al indica ion ha he eac ion leading o he o ma ion cc -[RuCl 2 (CO) 2 (ERR′) 2 ] p oceeds ia he in e media e o ma ion o [RuCl 2 (CO) 3 (ERR′)] (see Fig. 6). Fig. 6 The 77 Se NMR spec a o he eac ion mix u e o SeMe 2 and [RuCl 2 (CO) 3 ] 2 in CH 2 Cl 2 upon eflux. Dal on T ansac ions Pape This jou nal is © The Royal Socie y o Chemis y 2022 Dal on T ans. Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online The esonance a 41 ppm, which was de ec ed in he ea ly s ages o he eac ion, educed in in ensi y as a unc ion o ime and is en a i ely assigned o [Ru(EMe 2 )Cl(CO) 3 (μ-Cl) RuCl 2 (CO) 3 ](I2b). While his species has no been isola ed and unambiguously iden i ied, he PBE0-D3/de 2-TZVP ene - ge ics indica e ha he o ma ion o I2b is a ou able. I s 77 Se NMR chemical shi also shows a easonable alue. Fu he mo e, he obse ed dec ease o in ensi y o esonance a 41 ppm as he eac ion p og esses is consis en wi h he esonance a ising om an in e media e species like I2b. The o ma ion o [RuCl 2 (CO) 3 (ERR′)] (E = S, Se, Te; R, R′= Me, Ph) could also be de ec ed in some o he eac ion ba ches by NMR spec oscopy. The 13 C{ 1 H} (see Fig. S6 in ESI†) and 77 Se NMR spec a o [RuCl 2 (CO) 3 (SeMePh)] (11) we e eco ded om edissol ed c ys als isola ed om he eac ion mix u e ( he spec oscopic assignmen is discussed in sec ion 4.4 in ESI†). The 13 C esonances o he espec i e eac ion o SMePh and [RuCl 2 (CO) 3 ] 2 we e assigned om he 13 C{ 1 H} spec um eco ded di ec ly om he eac ion solu ion (see Fig. S4 in ESI†) by compa ison o he 13 C{ 1 H} spec um eco ded o he edissol ed c ys als o cc -[RuCl 2 (CO) 2 (SMePh) 2 ](2 cc ) (see Fig. S7 in ESI†). The eac ion mix u e o [RuCl 2 (CO) 3 ] 2 and TeMePh showed a 125 Te NMR esonance a 374 ppm, which disappea ed in a ew days. Taking in o accoun he epo ed app oxima e ela ionship be ween 125 Te and 77 Se chemical shi s in ela ed alkyl ellu ides [δ(Te) = (1.8)·δ(Se) 22 ], i can be concluded ha he assignmen o his esonance o [RuCl 2 (CO) 3 (TeMePh)] is consis en wi h he obse ed 77 Se chemical shi o 192 pm o [RuCl 2 (CO) 3 (SeMePh)]. Possible al e na i e eac ion p oduc s. I can be seen om Fig. 2 ha while cc -[RuCl 2 (CO) 2 (ERR′) 2 ] complexes a e ene ge- ically he mos s able isome s, he nex a ou able isome s ccc-[RuCl 2 (CO) 2 (EMe 2 ) 2 ] lie 15.4, 19.0, and 26.8 kJ mol −1 highe in ene gy o SMe 2 , SeMe 2 , and TeMe 2 , espec i ely. The espec i e alues o EMePh a e 19.5, 20.4, and 26.3 kJ mol −1 , and o EPh 2 14.3, 13.7, and 21.1 kJ mol −1 . Whe eas he o - ma ion o hese isome s migh be possible, we ha e no seen any indica ions ha any eac ions would ha e affo ded ccc- [RuCl 2 (CO) 2 (ERR′) 2 ]. We ca ied ou PBE0-D3/de 2-TZVP ene gy scan o he inal eac ion s ep o he eac ion o es he plausibili y o o ma ion o he ccc-isome s (see eqn (2)): ½RuCl2ðCOÞ3ðERR′Þ þ ERR′ !ccc ½RuCl2COðÞ 2ðERR′Þ2þCO ð2Þ The ene gy p o iles and he compu ed ene gy alues in he eac ion in ol ing EMe 2 a e shown in Fig. 7. The calcula ions clea ly show ha o ma ion o ccc- [RuCl 2 (CO) 2 (EMe 2 ) 2 ] is less likely han ha o cc - [RuCl 2 (CO) 2 (EMe 2 ) 2 ]. I can be seen om Fig. 7 ha he ac i- a ion ene gies o he ansi ion s a es leading o he ccc- isome a e ca. 30 kJ mol −1 highe han hose leading o he o - Fig. 7 The compa ison o he ene gy p ofiles o he eac ions [RuCl 2 (CO) 3 (EMe 2 )] + EMe 2 →cc -[RuCl 2 (CO) 2 (EMe 2 ) 2 ] + CO (g een line) and [RuCl 2 (CO) 3 (EMe 2 )] + EMe 2 →ccc-[RuCl 2 (CO) 2 (EMe 2 ) 2 ] + CO (blue line) in THF. The ΔG alues a e fixed by gi ing each in e media e I3a,b he ela i e alue o 0 kJ mol −1 . Pape Dal on T ansac ions Dal on T ans. This jou nal is © The Royal Socie y o Chemis y 2022 Open Access A icle. Published on 12 July 2022. Downloaded on 7/27/2022 10:12:31 AM. This a icle is licensed unde a C ea i e Commons A ibu ion 3.0 Unpo ed Licence. View A icle Online