The dual role of cis-[RuCl2(dmso)4] in the synthesis of new water-soluble Ru(II)-phosphane complexes and in the catalysis of redox isomerization of allylic alcohols in aqueous-organic biphasic systems

The dual ole o cis-[RuCl2(dmso)4] in he syn hesis o new wa e -soluble Ru(II)-phosphane complexes and in he ca alysis o edox isome iza ion o allylic alcohols in aqueous-o ganic biphasic sys ems An al Ud a dy, A ila Csaba Bényei, Ágnes Ka hó* Depa men o Physical Chemis y, Uni e si y o Deb ecen, Deb ecen, P.O.B. 7, H-4010, Hunga y. * Co esponding au ho . Á. Ka hó: phone: +36-52-512900; ax: +36-52-512915; E-mail: ka [email protected] Abs ac New ai -s able, wa e -soluble Ru(II)-phosphane complexes we e syn hesized in high pu i y by he eac ion o cis-[RuCl2(dmso)4] wi h 2 equi alen s o 1,3,5- iaza-7-phosphaadaman ane (p a) and i s N-me hyl and N-benzyl de i a i es (p a-Me and p a-Bn, espec i ely). All new complexes we e cha ac e ized by elemen a y analysis and spec oscopic me hods (NMR, ESI MS) and he molecula s uc u es o cis-cis- ans-[RuCl2(dmso)2(p a)2], cis-cis- ans- [RuCl2(dmso)2(p a-H)2]Cl2 (ob ained in acidic solu ions) and ha o cis-cis- ans- [RuCl2(dmso)2(p a-Me)2](CF3SO3)2 we e de e mined by single c ys al X- ay di ac ion. Unde mild condi ions, cis-[RuCl2(dmso)4] ac i ely ca alyzed he ans o ma ion o allylic alcohols in o he co esponding ke ones wi h 100 % selec i i y while in he same eac ion he new Ru(II)-p a complexes showed mode a e ac i i y and selec i i y. Highligh s  cis-[RuCl2(dmso)4] (1) was used as a wa e -soluble Ru(II) sou ce o syn hesis  New wa e -soluble Ru(II)-complexes we e ob ained om 1 and phospha iazaadaman anes (L).  Single c ys al X- ay s uc u es e idenced cis-cis- ans-[RuCl2(dmso)2L2] geome ies.  1 and he new complexes ac i ely ca alyzed he isome iza ion o allylic alcohols. Keywo ds: wa e soluble phosphanes, u henium, allylic alcohols, isome iza ion, biphasic ca alysis 1. In oduc ion Wa e is widely conside ed use ul o elimina ion o haza dous o ganic sol en s in o ganic syn hesis and ca alysis. An addi ional g een ea u e o applying wa e -soluble ca alys s is ha he use o aqueous-o ganic biphasic sys ems allows ecycling o he ca alys unde mild condi ions by easy phase sepa a ion.[1-4] The chemis y o Ru(II) ca alys s con aining wa e -soluble phosphanes as ligands has ecei ed conside able a en ion in ecen yea s.[4] In many cases, Ru(II)-complexes o e ia y phosphanes applied in homogeneous ca alysis a e syn hesized om RuCl3.aq as s a ing ma e ial. Howe e , ligand exchange eac ions o wa e -soluble Ru(II)-complexes con aining su icien ly labile ligands allow mo e p ecise con ol o he composi ion and s uc u e o he p oduc s.[5] Fo example, [Ru(H2O)6]( os)2 ( os = p- oluene-sul ona e) can be e icien ly used o his pu pose. Howe e , his compound is edious o syn hesize, highly sensi i e o oxygen and is s able only in acidic solu ions.[6,7] The u henium(II) dime hylsul oxide complexes, cis- and ans-[RuCl2(dmso)4] a e con enien ly p epa ed and easy- o-handle compounds.[8,9] Ea lie cis-[RuCl2(dmso)4], 1 was used as p ecu so o he syn hesis o Ru(II)-complexes wi h a yl, sul ona ed a yl, and cyclohexyl phosphanes, bo h in aqueous and in non-aqueous media.[8, 10-14] In addi ion, se e al ligands wi h N- and O-dono a oms we e s udied in subs i u ion eac ions o bo h isome s o [RuCl2(dmso)4].[15] This was –in pa – mo i a ed by he expec ed biological e ec s o he p oduc s.[16-19] While 1 i sel also shows an i umo and ema kable an ime as a ic ac i i y, ce ain o i s subs i u ed de i a i es a e e en mo e e ec i e.[20] 1,3,5-T iaza-7-phosphadaman ane (1,3,5-T iaza-7-phospha icyclo[3.3.1.1]decane, p a) is a small, alipha ic e ia y phosphane wi h a cage s uc u e, well soluble in wa e . Ru(II)-p a complexes such as [RuCl2(p a)4] ha e al eady been applied in biphasic ca alysis[21] and he ield is well e iewed.[5, 22,23] In con as o o he e ia y aminoalkylphosphanes whe e alkyla ion akes place on phospho us, p a is alkyla ed smoo hly on one o i s ni ogen a oms.[24] The cha ge and s e ic bulk o such ligands a e changed by qua e na iza ion and his is e lec ed also in hei wa e -solubili y.[25] Coo dina ion p ope ies o alkyl-p a de i a i es and ca aly ic applica ions o hei complexes ecei ed less a en ion han hose o p a. Ra e examples include he use o (p a-Bn)Cl (Scheme 1) in Rh-ca alyzed hyd o o myla ion o highe ole ins[26,27] and ha o [(η-a ene)RuCl2(p a-Bn)]Cl in hyd a ion o ni iles.[28] [CpRuCl(p a-Me)2](OSO2CF3)2 and [CpRu(p a-Me)2(H2O)](OSO2CF3)3 we e ound e ec i e ca alys s o he edox isome iza ion o allylic alcohols. [29 ] In addi ion, p a has been success ully used o syn hesis o an icance Ru(II)-a ene complexes[30]. I is in e es ing, he e o e, ha eac ions o p a and i s de i a i es wi h cis- o ans-[RuCl2(dmso)4] hi he o ha e no been s udied. Scheme 1. Wa e -soluble phosphanes used in his s udy He ein we epo he use o 1 o he syn hesis and cha ac e iza ion o se e al new wa e - soluble Ru(II)-complexes con aining he ligands shown in Scheme 1, and an explo a o y s udy o hei ca aly ic ac i i y in he hyd ogena ion and isome isa ion o allylic alcohols. S ikingly, 1 i sel was only sca cely used[31,32] as ca alys in such eac ions so i s s udy was also accomplished. 2. Resul s and Discussion 2.1. Reac ions o cis-[RuCl2(dmso)4] wi h wa e -soluble phosphanes Acco ding o he li e a u e,[10] boiling o a oluene suspension o 1 and h ee equi alen s o he wa e -soluble phosphane, m ppms, o 2 h esul ed in o ma ion o he mononuclea [RuCl2(dmso)(m ppms)3]. Howe e , we ound his eac ion a he slow and incomple e and 31P NMR indica ed he o ma ion o mo e han one p oduc . No signi ican imp o emen /op imiza ion could be eached by a ying he ligands (m ppms o m pp s), ligand o me al a io (1 o 3), sol en s ( oluene, me hanol o wa e ), eac ion ime o eac ion empe a u e. In con as o he a oma ic phosphanes, p a eac ed cleanly wi h 1 in chlo o o m. The eac ion was ollowed by u - is spec opho ome y (Figu e 1.). The isosbes ic poin a λ = 346 nm e e s o he o ma ion o a single p oduc (2). Fo ma ion o 2 became comple e in wo hou and he e we e no u he spec al changes. Figu e 1. Changes in u - is spec a measu ed in he solu ion o cis-[RuCl2(dmso)4] (1) and 2 p a as a unc ion o ime. Condi ions: c(1) = 0.001 M; T = 25 °C; = 0, 15, 30, 45, 60, 90 and 120 min. Only one single a δ = -60.7 ppm (in CDCl3) appea ed in he 31P NMR spec um. Based on in eg a ed 1H signal in ensi ies o ee and coo dina ed dmso as well as hose o coo dina ed p a we concluded ha he p oduc was [RuCl2(dmso)2(p a)2] (2). The single 31P signal e e s o he phosphanes being in ans posi ion each o he o he (Scheme 2). This obse a ion is in ag eemen wi h ha subs i u ion o chlo ide in his sol en is no a ou ed. The molecula s uc u e o 2 in solid s a e was con i med by single c ys al x- ay di ac ion (see la e ). Scheme 2. Syn hesis o Ru(II)-complexes con aining iazaphosphaadaman anes A oom empe a u e, coo dina ion o a u he phosphane ligand o 2 is slow and a a 4:1 [p a]:[1] a io only [RuCl2(dmso)2(p a)2] (2) was o med in he i s 90 min o he eac ion. Du ing he same eac ion ime bu a e lux empe a u e, an app oxima ely 3:2 mix u e o 2 and he known ans-[RuCl2(p a)4], 5 was ob ained (Scheme 2);[21,33] upon u he boiling he la e compound p ecipi a ed om he solu ion. Based on hese obse a ions [RuCl2(dmso)2(p a)2] could be syn hesized in pu e o m when [RuCl2(dmso)4] and p a we e le o eac in a 1:2 a io in chlo o o m o wo hou s a oom empe a u e (yield 82 %). In aqueous solu ion 2 is cha ac e ized by a single esonance a δ = -57.9 ppm in he 31P NMR spec um (Table 1). Table 1. 31P-NMR da a o wa e soluble Ru(II)–phosphane complexes in D2O 31P-NMR (ppm) [RuCl2(dmso)2(p a)2] (2) -57.9* [RuCl2(dmso)2(p a-Me)2](CF3SO3)2 (3) -38.9 [RuCl2(dmso)2(p a-Bn)2]Cl2 (4) -36.4 ans-[RuCl2(p a)4] (5) -51.6 ans-[Ru(H2O)2(p a)4]2+ (6) -52.9 * in CDCl3: δ = -60.7 ppm Since bo h p a and 1 a e soluble in wa e , hei eac ion was s udied in aqueous medium, as well. A oom empe a u e, only he cha ac e is ic single esonance o 2 (δ = - 57.9 ppm in D2O) was obse ed in he 31P NMR spec a independen o he [p a]:[1] a io being 1 o 2. In con as , a [p a]:[1]=3, albei in he i s 30 min o he eac ion exclusi ely 2 was de ec ed, la e a new single (δ = -52.9 ppm) g ew in g adually. Fo ma ion o his new species a oom empe a u e is slow e en a highe ligand excess ([p a]:[1]=4).The single 31P NMR esonance o his new compound is sligh ly di e en om ha o ans-[RuCl2(p a)4] (δ = -51.6 ppm in D2O),[21,33] howe e , i shows a simila p esence o magne ically equi alen phosphane ligands. We easoned, ha du ing he eac ion o 1 wi h p a in wa e , aqua ion could lead o he o ma ion o ans-[Ru(H2O)2(p a)4]2+ (6). This is co obo a ed by he inding ha when [RuCl2(dmso)2(p a)2] (2) was eac ed i s wi h AgNO3 ollowed by he addi ion o 2 equi alen s o p a, a e a eac ion ime o 2 h a oom empe a u e only he single a δ = -52.9 ppm was obse ed. The same signal was obse ed when 1 was dehalogena ed in eac ion wi h AgNO3, ollowed by addi ion o 4 equi alen s o p a. Fu he mo e, addi ion o KCl (5 Clˉ/Ru) o hese solu ions esul ed in he appea ance o he 31P NMR signal o ans-[RuCl2(p a)4] (5) on he expense o he one a -52.9 ppm. No e, ha in he eac ion o p a and [Ru(H2O)6]2+ only cis-[Ru(H2O)2(p a)4]2+ could be de ec ed.[7] The cis-[Ru(H2O)2(p a)4]2+ compound was also ob ained by addi ion o AgOT o he p oduc mix u e o cis-[RuCl2(p a)4] and [RuCl(H2O)(p a)4]+ o med by isible ligh i adia ion o 5 in wa e .[34] I is also wo h men ioning, ha in con as o he eac ion o [Ru(H2O)6]2+ and p a, o ma ion o mono- o is-phosphane complexes was no obse ed. In acidic solu ions bo h ee and coo dina ed p a can be p o ona ed on one o he ni ogen a oms. Figu e 2 shows he shi o he 31P NMR signal o [RuCl2(dmso)2(p a)2] as a unc ion o he acidi y o i s aqueous (D2O) solu ions. Figu e 2. Expe imen al (squa es) and calcula ed (solid line) 31P NMR chemical shi o [RuCl2(dmso)2(p a)2] s pD. Hende son-Hasselbach analysis o he da a ga e pKa = 3.40 (applying he pH = pD – 0.44 scaling[35]) and he 31P NMR shi s calcula ed wi h his alue a e also shown on Figu e 2. Li e a u e alues o he pKa o p a a y in he ange o 5.63-6.0,[7, 36-38] so he p o ona ion o coo dina ed p a in 2 akes place unde mo e acidic condi ions ela i e o he ee ligand. Single c ys als o 2a we e ob ained om hyd ochlo ic acid solu ions o 2. X- ay di ac ion analysis o he molecula s uc u e o 2a (see Supplemen a y In o ma ion: Figu e S1) showed ha bo h phosphane ligands had one p o ona ed ni ogen each. The mos in ensi e peak in he ESI mass spec um o 2 a m/z = 643.030 belongs o he monop o ona ed molecule, concei ably [RuCl2(dmso)2(p a)(p aH)]+ (Figu e S2), u he mo e, loss o dmso and chlo ide a e also indica ed by he signals a m/z = 565.070 ([RuCl2(dmso)(p a)(p aH)]+) and a m/z = 607.048 ([RuCl(dmso)2(p a)2]+). The eac ion o 1 and (p a-Bn)Cl in aqueous solu ion a oom empe a u e a a [p a- Bn]:[ 1]=2 a io yielded 3 wi h [RuCl2(dmso)2(p a-Bn)2]2+ as he sole p oduc . The u - isible spec um o he eac ion mix u e unde wen changes simila o hose shown abo e o he case o 1 wi h wo equi alen s o p a, and he spec al pa ame e s o 3 a e also simila o hose o 2. The eac ion was comple e in 1.5 h, and no sign o any o he species was de ec ed in he NMR spec a e en a highe empe a u e (up o T = 70 °C). 3 is s able o ai and i s bes sol en is wa e . Due o i s cha ge solubili y o 3 in wa e is app oxima ely 1.5 imes highe han ha o he neu al 2 (see Expe imen al). The mos in ensi e ESI MS peak a m/z = 576.100 belongs o [RuCl2(dmso)2(p a-Bn)]+ (Figu e S2). The mono-dmso complex ion, [RuCl2(dmso)(p a-Bn)]+ (m/z = 500.003) and chlo ide-associa ed ions such as {[RuCl2(dmso)2(p a-Bn)2]Cl}+ (m/z = 860.100) and {[RuCl2(dmso)(p a- Bn)2]Cl}+ (m/z = 782.100), could also be iden i ied. [RuCl2(dmso)2(p a-Me)2](CF3SO3)2 (4) was p epa ed in he eac ion o 1 wi h (p a- Me)CF3SO3. This ligand and 1 ([p a-Me]:[1]=2) we e eac ed in wa e (o me hanol) a oom empe a u e o 2 h yielding exclusi ely [RuCl2(dmso)2(p a-Me)2]2+ wha was isola ed as i la e sal . 4 is s able o ai and i s solubili y is app oxima ely he double o ha o he neu al 2, and is somewha highe han ha o 3The mos in ensi e ESI-MS peak a m/z = 499.947 belongs o [RuCl2(dmso)2(p a-Me)]+ (Figu e S2). The mono-dmso complex ion, [RuCl2(dmso)(p a-Me)]+ (m/z = 421.947) and i la e-associa ed ions such as {[RuCl2(dmso)2(p a-Me)2](CF3SO3)}+ (m/z = 821.013) and {[RuCl2(dmso)(p a- Me)2](CF3SO3)}+ (m/z = 743.005), and {[RuCl2(p a-Me)2](CF3SO3)}+ (m/z = 665.039) could also be iden i ied. 2.2. Molecula s uc u es o cis-cis- ans-[RuCl2(dmso)2(p a)2] (2), cis-cis- ans- [RuCl2(dmso)2(p aH)2]Cl2 (2a) and cis-cis- ans-[RuCl2(dmso)2(p a-Me)2](CF3SO3)2 (4) in solid s a e Resul s o X- ay s uc u e de e mina ions a e summa ized in Table 2. Sea ch o he Camb idge S uc u al Da abase (Ve . 5.33, Upda e May, 2012)[39] e ealed ha all RuCl2P2S2 complexes in he da abase con ain exclusi ely biden a e ligands wi h P-S, P-P o S-S dono pai s. In ac , 2, 2a and 4 a e he i s c ys allog aphically cha ac e ized complexes wi h RuCl2P2S2 coo dina ion con aining monoden a e ligands. The wo phospho us a oms a e in ans-posi ion, howe e , he P-Ru-P angles signi ican ly de ia e om 180° being 161° in 2, 168° in 2a and 165° in 4. In he as numbe o RuP2 complexes (o e 4500 hi s in CSD) he P-Ru-P angles a ely de ia e om 180° o 90°: in he c ys als ob ained om [Ru(H2O)6]2+ wi h p a o i s de i a i es[7] ( ans-[Ru(H2O)4(p a)2]2+, ans-[Ru(H2O)4(p a- Me)2]4+, ans-[Ru(H2O)4(p a-H)2]4+) as well as in ans-[RuI4(p a-Me)2]40 and ans- [RuCl4(p a-H)2]41 his angle is 180° as u henium a om is in he in e sion cen e o he la ice. Conce ning he eac ion mechanism, one o he possible pa hways is he isome iza ion o allylic alcohols o sa u a ed ke ones ollowed by hyd ogena ion o he la e o sa u a ed alcohols. Howe e , in independen eac ions no hyd ogena ions o he espec i e ke ones occu ed (ei he wi h H2 o wi h o ma e), he e o e wi h he ca alys s desc ibed abo e we conside isome iza ion and hyd ogena ion o allylic alcohols as pa allel eac ions. 3. Conclusions The easily a ailable cis-[RuCl2(dmso)4] is use ul as a Ru(II)-sou ce no only in o ganic sol en s, bu in wa e , as well. 1,3,5-T iaza-7-phosphaadaman ane (p a) is soluble in bo h ypes o media and i s eac ions wi h cis-[RuCl2(dmso)4] esul ed in he same p oduc , cis-cis- ans-[RuCl2(dmso)2(p a)2] (2) in bo h CHCl3 and wa e . N-alkyl de i a i es o p a (L = {p a- Bn}Cl; {p a-Me}CF3SO3) also easily eplace wo dmso ligands in ans posi ions o cis- [RuCl2(dmso)4] in aqueous solu ion o o m ai -s able, cis-cis- ans-[RuCl2(dmso)2(L)2] complexes (3, 4). O he new compounds, 2, 2a and 4 a e he i s c ys allog aphically cha ac e ized complexes wi h RuCl2P2S2 coo dina ion con aining monoden a e ligands. The P-Ru-P angles in hese ans-bisphosphane complexes signi ican ly de ia e om 180° (161° in 2, 168° in 2a and 165° in 4). I was shown he e o he i s ime, ha apa om i s use ul ole in he syn hesis o wa e -soluble Ru(II)-complexes, cis-[RuCl2(dmso)4] is an excellen ca alys o aqueous- o ganic biphasic isome iza ion o allylic alcohols. The eac ions p oceeded wi h 100 % o he espec i e ke ones using Na- o ma e as a H-sou ce. Unde he same condi ions he ac i i ies o 2, 3 and 4 a e 45-65 % o ha o cis-[RuCl2(dmso)4], and he eac ions a e also less selec i e leading o he o ma ion o small amoun s o oc an-3-ol, oo. 4. Expe imen al Sec ion 4.1. Gene al Rema ks Allylic alcohols (Ald ich) and o he eagen s and sol en s we e comme cially a ailable and used as ecei ed. The wa e -soluble phosphane ligands, m ppms,[50] m pp s (m pp s = P(C6H4- 3-SO3Na)3),[51] p a,[52] (p a-Bn)Cl (1-benzyl-1-azonia-3,5-diaza-7-phosphaadaman yl chlo ide),[36] and cis-[RuCl2(dmso)4] (1),[8] we e p epa ed acco ding o he li e a u e. (p a- Me)CF3SO3[25] was kindly supplied by P o . A. Rome osa (U. Alme ía, Spain). 1 is a ligh sensi i e compound,[9,53] he e o e i s eac ions we e s udied wi h he ca e ul exclusion o ligh . All eac ions and manipula ions we e ca ied ou unde a gon a mosphe e. Reac ion mix u es we e analyzed by gas ch oma og aphy (HP5890 Se ies II; Ch ompack WCOT Fused Silica 30m*32mm CP WAX52CB; FID; ca ie gas: a gon). The p oduc s we e iden i ied by compa ison o known compounds. 1H, 31P and 13C NMR spec a we e eco ded on a B uke A ance 360 MHz spec ome e and e e enced o 3-( ime hylsilyl)p opanesul onic acid Na- sal (DSS). ESI mass da a we e collec ed on a BRUKER BioTOF II ESI-TOF spec ome e . Solubili ies we e de e mined by inc emen al addi ion o he compounds o wa e . Comple e dissolu ion was checked by lase ligh sca e ing. 4.2. Syn hesis and cha ac e iza ion o Ru(II) complexes 4.2.1. P epa a ion o cis-cis- ans-[RuCl2(dmso)2(p a)2], (2) In he da k, a mix u e o 1 (400 mg 0.82 mmol) and p a (259 mg, 1.64 mmol ) in chlo o o m (5 mL) was s i ed o 2 h a oom empe a u e. Then mos o he sol en was emo ed unde acuum and he esidue was i u a ed wi h die hyl e he o p o ide a pale yellow solid. This was washed wi h ace one and wi h die hyl e he and d ied unde A o esul in a s ongly hyg oscopic solid. Yield 527 mg (82 %). X- ay quali y c ys als we e g own by slow di usion o die hyl e he in o a chlo o o m solu ion o 2 a -15 °C . Anal. calc. o RuC16Cl2H36N6O2P2S2 (2.0.5 CHCl3) (M=642.30) C 28.22, H 5.23, N 11.97, S 9.13 %; ound C 28.67, H 5.40, N 12.17, S 9.98 %. S25 °C=34 mg/mL wa e . λmax(H2O)/nm 338 (ε/dm3mol-1cm-1 449) 1H NMR: (360 MHz, CDCl3, 25 °C) δ = 3.35 (s, 12 H, S-dmso, CH3), 4.43 (s, 12 H, PCH2N), 4.52 (s, 12 H, NCH2N) ppm; 1H NMR: (360 MHz; D2O, 25 °C) δ = 3.31 (s, 12 H, S-dmso, CH3), 4.26 (s, 12 H, PCH2N), 4.43 (s, 12 H, NCH2N) ppm; 13C NMR (90 MHz, CDCl3, 25 °C) δ = 51.18 (s, S-dmso, CH3), 51.39 ( , JPC= 7 Hz PCH2N), 73.07 (s, NCH2N ), ppm; 31P{1H} NMR (145 MHz, 25 °C) in CDCl3 δ = -60.7 (s), in D2O δ = -57.9 (s) ppm. MS (ESI+): m/z obse ed 643.030, calcd. 643.031 o [RuCl2(dmso)2(p a)(p a-H)]+. C ys als o cis-cis- ans-[RuCl2(dmso)2(p aH)2]Cl2, (2a) we e ob ained by dissol ing 10 mg o 2 in 1 mL o 0.1 M HCl and hen i was laye ed wi h 1 mL o e hanol. Anal. calc. o RuC16Cl4H38N6O2P2S2 (2a.3H2O) C 24.97, H 5.76, N 10.92, S 8.33 %; ound C 24.91, H 5.53, N 10.82, S 8.33 %. 4.2.2. P epa a ion o cis-cis- ans-[RuCl2(dmso)2(p a-Bn)2]Cl2, (3) 1 (200 mg 0.41 mmol) dissol ed in 3 mL o wa e was added o an aqueous solu ion (2 mL) o (p a-Bn)Cl (234 mg, 0.82 mmol). The mix u e was s i ed o 2 h a oom empe a u e in he da k. Then he sol en was emo ed unde acuum and he esidue was edissol ed in a small amoun o me hanol. Die hyl e he was added o he solu ion whe eupon a yellow solid p ecipi a ed. This was washed wi h ace one and wi h die hyl e he and d ied unde A . Yield 246 mg, 66 %. Anal. calc. o RuC30Cl4H50N6O2P2S2 (3.2H2O) (M=895.71) C 38.67, H 5.84, N 9.02 %; ound C 38.25, H 6.17, N 8.79 %. λmax(H2O)/nm 341 (ε/dm3 mol-1 cm-1 691) . 1H NMR: (360 MHz, D2O, 25 °C) δ =3.29-4.27 (m, 8 H, NCH2P), 3.64 (s, 12 H, S-dmso, CH3), 4.19 (m, 4 H, N+CH2Ph), 4.31 (m, 4 H, N+CH2P), 4.51-4.61 (m, 4 H, NCH2N), 4.92- 5.09 (m, 8 H, N+CH2N), 7.57-7.46 (m, 10 H, Ph) ppm; 13C NMR (90 MHz, D2O, 25 °C), δ = 47.25 ( , JPC=8 Hz, NCH2P), 50.16 (s, S-dmso, CH3), 51.99 (d, JPC=8 Hz, N+CH2P), 66.37 (s, NCH2N), 69.80 (s, N+CH2Ph), 78.71 (s, N+CH2N), 124.22 (s, Ph), 129.46 (s, Ph), 131.18 (s, Ph), 132.83 (s, Ph) ppm; 31P{1H} NMR (145 MHz, D2O, 25 °C) δ = -36.4 (s) ppm. MS (ESI+): m/z obse ed 860.100, calcd. 860.265 o {[RuCl2(dmso)2(p a-Bn)2]Cl}+. S25 °C= 50 mg/mL wa e . 4.2.3. P epa a ion o cis-cis- ans-[RuCl2(dmso)2(p a-Me)2](CF3SO3)2, (4) In he da k, 1 (100 mg 0.21 mmol) and (p a-Me)(CF3SO3) (132.7 mg, 0.41 mmol) was dissol ed in 5 mL o wa e . The solu ion was s i ed o 4 h a oom empe a u e and hen he sol en was emo ed unde acuum. The esidue was dissol ed in a small amoun o me hanol and 4 was p ecipi a ed wi h die hyl e he o yield a pale yellow solid. This was washed wi h ace one and wi h die hyl e he and d ied unde A . Yield 134 mg, 67 %. X- ay quali y c ys als we e ob ained by slow di usion o me hanol in o aqueous solu ion o 4. Anal. calc. o RuC20Cl2F6H42N6O8P2S2 (4.2H2O) (M=906.62)) C 23.86, H 4.60, N 8.34, S 12.74 %; ound C 23.99, H 4.53, N 8.18, S 13.00 %. λmax(H2O)/nm 344 (ε/dm3mol-1cm-1 480). 1H NMR: (360 MHz, D2O, 25 °C), δ = 2.84 (s, 6 H, N+-CH3), 3.38 (s, 12 H, S-dmso, CH3), 4.32 (s, 8 H, NCH2P), 4.44-4.38 (4 H, m, N+CH2P), 4.52 (m, 4 H, NCH2N), 4.91-5.10 (m, 8 H, N+CH2N) ppm; 1H NMR: (360 MHz, MeOD, 25 °C), δ = 4.31 (s, 6 H, N+-CH3), 4.81 (s, 12 H, S-dmso, CH3), 5.83 (m, 8 H, NCH2P), 5.90 (m, 4 H, N+CH2P), 5.95 (m, 4 H, NCH2N),6.61-6.69 (m, 8 H, N+CH2N) ppm; 13C NMR (90 MHz, D2O, 25 °C) δ = 46.97 ( , JPC= 7 Hz, NCH2P), 49.43 (s, N+-CH3), 50.14 (s, S-dmso, CH3), 55.38 ( , N+CH2P), 68.79 (s, NCH2N), 79.99 (s, N+CH2N), 121.34 (m, CF3SO3-) ppm; 31P{1H} NMR (145 MHz, 25 °C) in D2O δ = -39.61 (s), in MeOD δ = -37.67 (s) ppm; 19F{1H} NMR (283 MHz, D2O, 25 °C) δ = -79.10 (s, CF3SO3-) ppm. MS (ESI+): m/z obse ed 821.013, calcd. 821.022 o {[RuCl2(dmso)2(p a-me)2](CF3SO3)}+. S25 °C=63 mg/mL wa e . 4.3. 31P-NMR pH i a ions A pH-dependen se ies o 31P-NMR spec a we e eco ded on a B uke 360 MHz ins umen a 25 °C and 0.2 mol/dm3 KNO3 ionic s eng h. D2O was used as a sol en . The pH measu emen s in he pH ange 1.1-7.0 o [RuCl2(dmso)2(p a)2], 2 we e pe o med in 0.5 cm3 essels a a complex concen a ion o 0.01 mol/dm3. Small amoun s o cc. NaOD and DNO3 solu ions we e used o adjus he pH measu ed using a Radelkis OK117 pH me e and a combined elec ode. 4.4. X- ay c ys allog aphic s udies X- ay da a collec ion was pe o med using a B uke -Nonius MACH3 di ac ome e equipped wi h a poin de ec o using g aphi e-monoch oma ed Mo-Kα adia ion, λ = 0.71073 Å. The s uc u es we e sol ed by he SIR-92 p og am[54] and e ined by ull-ma ix leas -squa es me hod on F2, wi h all non-hyd ogen a oms e ined wi h aniso opic he mal pa ame e s excep in he sol en egion in 2 since chlo o o m in wo o ien a ions occupies a channel in he la ice (Figu e S1.a). Re inemen was pe o med using he SHELXL-97 package;[55] publica ion ma e ial was p epa ed wi h he WINGX sui e.[56] Hyd ogen a oms we e loca ed geome ically and e ined in he igid mode o ound a he di e ence Fou ie map. Sol en wa e molecules in 2a and 4 (Figu e S1.b and S1.c) ha e pa ial occupancy and can ha e a ious o ien a ions o ming di e en hyd ogen bond ne wo ks wi h accep o s esul ing shi and e o s e en in he las s age o he e inemen . 4.5. Gene al P ocedu e o Ca aly ic Isome iza ion o Allylic Alcohols Unde an ine a mosphe e, he ca alys p ecu so (0.01 mmol) and Na- o ma e (0.5 mmol) we e dissol ed in 3 mL o deoxygena ed wa e . The solu ion was hen hea ed o he indica ed empe a u e and hen allylic alcohol (0.5 mmol, in 1 mL o oluene) was in oduced. The sys em was apidly s i ed o one hou and hen was cooled o oom empe a u e. The sepa a ed o ganic phase was il e ed h ough a sho silica gel column and was subjec ed o gas ch oma og aphy. Supplemen a y ma e ial CCDC 859702- 859704 con ain he supplemen a y c ys allog aphic da a o he u henium complexes 2, 2a and 4. These da a can be ob ained ee o cha ge om Camb idge C ys allog aphic Da a Cen e ia h p://www.ccdc.cam.ac.uk/da a- eques /ci . Supplemen a y da a ela ed o his a icle can be ound in he online e sion, a doi…. Acknowledgmen s The au ho s a e indeb ed o P o . An onio Rome osa (U. Alme ía, Spain) o he gene ous supply o (p a-Me)CF3SO3 and o he use ul ad ices on he syn hesis o 4, as well as o suppo o he s ay o A. Ud a dy in his labo a o y. Help ul discussions wi h P o . Fe enc Joó, D . Ka alin Ősz and M . Im e Sza má i a e g a e ully acknowledged. Thanks a e due o D . A ila Kiss-Szikszay o he elemen a y analyses and o D . Lajos Nagy o he ESI-MS measu emen s. This esea ch was suppo ed by he EU and co- inanced by he Eu opean Social Fund h ough he Social Renewal Ope a ional P og amme unde he p ojec s TÁMOP-4.2.1/B- 09/1/KONV-2010-0007 and TÁMOP-4.2.2-08/1-2008-0012 (CHEMIKUT). Financial suppo o TEVA Hunga y L d. and ha o he Na ional Resea ch Fund o Hunga y (OTKA K 101372) is also app ecia ed. A. Ud a dy is g a e ul o he p edoc o al employmen g an TÁMOP-4.2.2/B-10/1/KONV-2010-0024. Re e ences [1] F. Joó in Wa e in O ganic Syn hesis (in he se ies o Science o Syn hesis), Ed. S. Kobayashi, Geo g Thieme Ve lag KG, S u ga . New Yo k, 2012, pp. 95-119 [2] F Joó, Á Ka hó in Handbook o G een Chemis y: Reac ions in Wa e (ed.: Chao-Jun Li) Weinheim: Wiley-VCH, 2010, pp. 389-408 [3] F. Joó, Á. Ka hó, in Handbook o Homogeneous Hyd ogena ion, (Eds. J.G. de V ies and C.J. Else ie ) Wiley-VCH, Weinheim, 2007, ol. 3, ch. 38, pp. 1327-1359. [4] F. Joó, Aqueous O ganome allic Ca alysis, Kluwe , Do d ech , 2001. [5] J. B a o, S. Bolano, L. Gonsal i, M. 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