Potential rhodium and ruthenium carbonyl complexes of phosphine-chalcogen (P-O/S/Se) donor ligands and catalytic applications (original) (raw)
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Journal of Organometallic Chemistry, 2011
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Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2009
The polymeric ruthenium(II) carbonyl complex, [Ru(CO) 2 Cl 2 ] n reacts with 1,1,1-tris-(diphenylphosphinomethyl)ethane trichalcogenide ligands, [CH 3 C(CH 2 P(X)Ph 2) 3 ], where X = Se(a), S(b) and O(c) in 1:1 (metal:ligand) molar ratio to afford hexa-coordinated complexes of the type 2-(X,X)-[Ru(CO) 2 Cl 2 P 3 X 3 ] (1a-c). The complexes 1a-c exhibit two equally intense (CO) bands in the range 1979-2060 cm −1 indicating cis-disposition of the two terminal carbonyl groups. The values of (CO) frequencies containing different ligands, in general, follow the order: P 3 O 3 > P 3 S 3 > P 3 Se 3 which may be explained in terms of 'Soft-Hard' (Ru(II)-O) and 'Soft-Soft' (Ru(II)-S/Se) interactions. The complexes have been characterized by elemental analyses, mass, 1 H, 31 P, 77 Se and 13 C NMR spectroscopy. The thermal stability of the complexes has also been studied.
Rhodium(I) carbonyl complexes of triphenylphosphine chalcogenides and their catalytic activity
2000
Rhodium(I) carbonyl complexes [Rh(CO)2ClL] where L = Ph3PO, Ph3PS and Ph3PSe, were synthesized and characterized by elemental analysis, i.r. and by 1H-, 13C- and 31P-n.m.r. spectroscopy. The vBD;(CO) band frequencies in the complexes follow the order: Ph3PO > Ph3PS > Ph3PSe, in keeping with the hard/soft nature of the interactions. The complexes undergo oxidative additions with electrophiles such as MeI,
Tricyclohexylphosphine complexes of rhodium, iridium and ruthenium
Inorganica Chimica Acta, 1979
Our interest in activation of carbon dioxide [ 1 ] and the report of a well-characterized Ni(CO,)(PCy,), complex (PCy3 = tricyclohexylphosphine) [2] led us to investigate tricyclohexylphosphine complexes of rhodium, iridium, and ruthenium. The basic and bulky phosphine is a good ancillary ligand for a coordinatively unsaturated complex likely to react with small gas molecules; this had been well-documented for rhodium [3], but at the time our studies were initiated little had been reported on iridium and ruthenium species, although carbonyls complexes such as IrCl(CO)(PCy,), [4], HRuCl(CO)(PCy3)3
Synthesis and Reactions of Cp-Linked Phosphine Complexes of Rhodium
Organometallics, 1998
The linked Cp ligand [C 5 H 4 SiMe 2 CH 2 PPh 2 ]has been used to synthesize several rhodium derivatives. Reaction with [RhClL 2 ] 2 , where L) C 2 H 4 , C 8 H 14 , or CO, gives (η 5 :η 1-C 5 H 4 SiMe 2-CH 2 PPh 2)Rh(L) complexes, which have been characterized by single-crystal X-ray diffraction. Reaction of the ethylene complex with CO or PMe 3 gives the carbonyl-and phosphinesubstituted derivatives, respectively. Irradiation of the ethylene complex in the presence of hydrogen gives a new binuclear polyhydride, also structurally characterized, in which the chelating ligand spans the two metal centers. Reaction of the ethylene complex with iodine leads to the formation of the diiodide (η 5 :η 1-C 5 H 4 SiMe 2 CH 2 PPh 2)RhI 2 , which in turn can be converted to the dihydride (η 5 :η 1-C 5 H 4 SiMe 2 CH 2 PPh 2)RhH 2 by reaction with NaAl(OCH 2-CH 2 OCH 3) 2 H 2. The reactivity of the dihydride toward C-H bond activation has been investigated. While benzene does not give a stable oxidative addition adduct, pentafluorobenzene yields (η 5 :η 1-C 5 H 4 SiMe 2 CH 2 PPh 2)Rh(C 6 F 5)H, which was structurally characterized as its chloro derivative. Reaction of the dihydride with C 6 F 6 gives the η 2 complex (η 5 :η 1-C 5 H 4 SiMe 2 CH 2 PPh 2)Rh(η 2-C 6 F 6), also structurally characterized.
Journal of Organometallic Chemistry, 1999
The novel rhodium complexes with the bidentate PO ligand (PO = OC 6 H 4 PPh 2 − ) of the form Rh(PO)(CO)L (L a =POH= HOC 6 H 4 PPh 2 (1), PPh 3 (2), P(NC 4 H 4 ) 3 (4), PPh 2 (NC 4 H 4 ) (6)) and Rh(PO)L 2 (L b = P(OPh) 3 (3), P(NC 4 H 4 ) 3 (5)) were obtained by ligand exchange in Rh(b-diketone)(CO) 2 , Rh(b-diketone)(CO)L and Rh(b-diketone)L 2 complexes. All complexes of the Rh(PO)(CO)L a type exist in solution as isomers with both phosphorus atoms in the trans position as was shown by 31 P{ 1 H}-NMR. The trans influence of the phosphorus atom of a bidentate PO ligand is stronger than that of oxygen atom, which is manifested by the differences of Rh-P bonds in (2) (2.283(1) and 2.327(1) Å ) and of Rh -P (phosphite) bonds in (3) (2.233(2) and 2.139(2) Å ). The complexes (1) and (2) used alone or with an excess of free phosphine (POH, PPh 3 , P(NC 4 H 4 ) 3 ) are not active in hexen-1-e hydroformylation at 1 MPa CO/H 2 =1 and at 353 K. The lack of catalytic activity is explained by the extremely high stability of the chelate (PO) ring which does not allow the formation of the active form of the catalyst. In contrast, the complex (3) used alone as the catalyst precursor produces 54 and 72.9% of aldehydes when used with a six-fold excess of P(OPh) 3 . Complex (1) modified with P(OPh) 3 catalyses hexen-1-e hydroformylation with a 73.6 -84.6% yield of aldehydes. Under hydroformylation reaction conditions, the PO ligand is removed from the coordination sphere of (1) and complexes of the form HRh(CO){P(OPh) 3 } 3 and HRh{P(OPh) 3 } 4 are formed.
Rhodium(I) carbonyl complexes of ether-phosphine ligands and their reactivity
Applied Organometallic Chemistry, 2002
The reactions of dimeric complex [Rh(CO) 2 Cl] 2 with hemilabile ether-phosphine ligands Ph 2 P(CH 2 ) n OR [n = 1, R = CH 3 (a); n = 2, R = C 2 H 5 (b)] yield cis-[Rh(CO) 2 Cl(P $ O)] (1) [P $ O = h 1 -(P) coordinated]. Halide abstraction reactions of 1 with AgClO 4 produce cis-[Rh(CO) 2 (P O)]ClO 4 (2) [P O = h 2 -(P,O)chelated]. Oxidative addition reactions of 1 with CH 3 I and I 2 give rhodium(III) complexes [Rh(CO)(COCH 3 )ClI(P O)] (3) and [Rh(CO)ClI 2 (P O)] (4) respectively. The complexes have been characterized by elemental analyses, IR, 1 H, 13 C and 31 P NMR spectroscopy. The catalytic activity of 1 for carbonylation of methanol is higher than that of the well-known [Rh(CO) 2 I 2 ] À species. a Conversion (%) = {[CO consumed (mol)]/[CO charged (mol)]} Â 100. CO consumption was determined from analysis of the products by GC. b Yields of AcOH and MeOAc were obtained from GC analyses. c TON = Amount of product (mol)/[Amount of catalyst (Rh mol) Â reaction time (h)].
Journal of Organometallic Chemistry, 2009
Ruthenium complexes [(g 5-C 5 H 5)Ru(j 1-P-PPh 2 Py)(PPh 3)Cl] (1) and [(g 5-C 5 H 5)Ru(j 2-P-N-PPh 2 Py)(PPh 3)] + (1a) containing diphenyl-2-pyridylphosphine (PPh 2 Py) are reported. Coordinated PPh 2 Py in the complex [(g 5-C 5 H 5)Ru(j 1-P-PPh 2 Py)(PPh 3)Cl] (1) exhibits monodentate behavior. In presence of NH 4 PF 6 in methanol at room temperature it afforded chelated complex [(g 5-C 5 H 5)Ru(j 2-P,N-PPh 2 Py)(PPh 3)] + (1a). Further, 1 reacted with various species viz., CH 3 CN, NaCN, NH 4 SCN and NaN 3 to afford cationic and neutral complexes [(g 5-C 5 H 5)Ru(j 1-P-PPh 2 Py)(PPh 3)L] + and [(g 5-C 5 H 5)Ru(j 1-P-PPh 2 Py)(PPh 3)L] [L = CH 3 CN (1b); CN À (1c); N 3 À (1d) and SCN À (1e)] and it's reaction with N,N-donor chelating ligands dimethylglyoxime (H 2 dmg) and 1,2-phenylenediamine (pda) gave cationic complexes [(g 5-C 5 H 5)Ru (j 1-P-PPh 2 Py)(j 2-N-N)]PF 6 [j 2-N-N = dmg (1f) and pda (1g)]. The complexes 1-1g have been characterized by physicochemical techniques and crystal structures of 1, 1a, 1c, 1e and 1f have been determined by single crystal X-ray analyses. Catalytic potential of the complex 1 has been evaluated in water under aerobic conditions. It was observed that the complex 1 selectively catalyzes reduction of aldehyde into alcohol.
Rhodium phosphine complexes as homogeneous catalysts
Journal of Molecular Catalysis, 1984
Using catalysts prepared in situ from [ Rh(NBD)C112 and chiral diphosphines of the type Ph2PCHRCH2PPh2 (R = Ph, i-Pr, PhCH,) optical yields above 60% were achieved in the hydrogenation of PhMeC=NCH*Ph. Although reproducibility of the results was poor, it can be concluded that the chiral diphosphines DIOP and diPAMP are much less effective, and that the halide ligand is necessary for good enantioselectivity.
Polyhedron, 1992
The complexes [Ru(S,S),(PPh,),] [S,S = EtCOCS2-, (CHJ4NCS2-] react with a variety of tertiary phosphines with the substitution of triphenylphosphine and the formation of [Ru(S,S),(PR,),]. The reaction occurs with the formation of the cis isomer, except for the complex with PMe*Ph that gives rise to the tram isomer as the crystal structure shows. The effect of the different phosphines on the ruthenium complex is analysed in terms of the spectroscopic and electrochemical properties of the isolated compounds. The cyclic voltammetric studies of the ci, Gomplexes show that isomerization to the tram isomer occurs on oxidation. This isomerization is not observed in the trans-[Ru(S,S),(PMe,Ph),] complexes that give rise to stable trans-ruthenium(II)/ruthenium(III) couples. In a similar way the diphosphine complexes afford a quasi-reversible cis-ruthenium(II)/ruthenium(III) process.