Neutral and Cationic Hydridoruthenium Tetrakiscarbene Complexes (original) (raw)
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Ruthenium Hydride Complexes of 1,2-Dicyclohexylimidazol-2-ylidene
Organometallics, 2005
The mono and bis N-heterocyclic carbene (NHC) complexes Ru(ICy)(PPh 3) 2 (CO)H 2 (1) and Ru(ICy) 2 (PPh 3)(CO)H 2 (2) (ICy) 1,2-dicyclohexylimidazol-2-ylidene) were isolated from the reaction of Ru(PPh 3) 3 (CO)H 2 with ICy at elevated temperature. X-ray crystallography revealed that 1 contains a trans arrangement of the PPh 3 ligands with the ICy trans to hydride; in complex 2, the two ICy ligands are cis to one another. Both 1 and 2 undergo H/D exchange with D 2 , as well as reacting rapidly with CO to give Ru(ICy)(PPh 3)(CO) 3 (3) and Ru(ICy) 2 (CO) 3 (4). Addition of CO 2 to solutions of 2 resulted in insertion into one of the Ru-H bonds to afford both the κ 1-and κ 2-formate complexes Ru(ICy) 2 (PPh 3)(CO)(κ 1-OCHO)H (5) and Ru(ICy) 2 (CO)(κ 2-OCHO)H (6). Addition of CO 2 to 1 gave solely Ru(ICy)(PPh 3)(CO)-(κ 2-OCHO)H (7). The product from reaction of ICy with Ru(PPh 3) 3 HCl proves to be solvent dependent, generating two isomers of the mono-NHC complex Ru(ICy)(PPh 3) 2 HCl (8a,b) in dichloromethane but the bis-NHC species Ru(ICy) 2 (PPh 3)HCl (10) in THF. An agostic interaction between Ru and a-CH 2 hydrogen of the ICy ligand is apparent both in the X-ray crystal structure of 8a and also in solution. This interaction is broken upon addition of CO, which yields Ru(ICy)(PPh 3) 2 (CO)HCl (9). The molecular structure of the coordinatively unsaturated species 10 is devoid of any agostic bonding.
Organometallics, 1999
The trisacetonitrile complexes [IrClH(P i Pr 3 )(NCCH 3 ) 3 ]BF 4 (1) and [IrH 2 (P i Pr 3 )(NCCH 3 ) 3 ]-BF 4 (2) have been prepared in one-pot reactions with high yields by reaction of the iridium-(I) dimers [Ir(µ-Cl)(coe) 2 ] 2 and [Ir(µ-OMe)(cod) 2 ] 2 with the phosphonium salt [HP i Pr 3 ]BF 4 . The rates of exchange between free acetonitrile and the labile acetonitrile ligands of complexes 1 and 2 have been measured by NMR spectroscopy. This kinetic study has shown that both complexes readily dissociate one acetonitrile ligand trans to hydride, giving rise to fluxional five-coordinate intermediates. Substitution products 3-7 have been obtained by treatment of complexes 1 and 2 with CO and PMe 3 . The structures determined for 3-7 can be rationalized on the basis of the steric requirements of the ligands, indicating that the products are formed by thermodynamic control. Ethene inserts reversibly into the Ir-H bond of 1 to give the compound [IrCl(Et)(P i Pr 3 )(NCCH 3 ) 3 ]BF 4 (8), which has been used for the preparation of the stable ethyliridium(III) complexes [IrCl(Et)(P i Pr 3 )(Py) 2 (NCCH 3 )]BF 4 (9) and [Ir(η 2 -O 2 CCH 3 )Cl(Et)(P i Pr 3 )(NCCH 3 ) 3 ] (10), respectively. The molecular structure of 10 has been determined by X-ray crystallography. The reaction of 2 with ethene, at low temperature, results in the sequential formation of the ethene complex [IrH 2 (
Organometallics, 1995
The reaction of the dimer [ {(y6-p-cymene)RuC1)2(p-Cl)21 (p-cymene = p-isopropylmethylbenzene) with 2,2'-biimidazole (HzBim) afforded the chloride complex [(v6-p-cymene)Ru-(H2Bim)CllC1(1) which has also been isolated as the tetrafluoroborate salt [(v6-p-cymene)Ru(H2-Bim)ClIBF4 (2) by metathesis with NaBF4. Complex 1 underwent reaction with [M(acac)-Lz] yielding the corresponding heterobinuclear species [(v6-p-cymene)C1Ru(-HBim)MC1L2] (M = Rh; L2 = cis,cis-1,5-cyclooctadiene (COD) (3), (C0)2 (4); M = Ir, L2 = COD (5)l. Complexes 3-5 exhibit a dynamic behavior which equilibrates the two imidazole rings of the HBim bridging ligand. The reaction of 4 with KOH led to two tetranuclear isomers [(y6-p-cymene)C1Ru(p-Bim)Rh(CO)212 (6) which in solution reached an equilibrium with a K value for the process 6b-a I 0.11. Reaction of [(y6-p-cymene)Ru(acac)C11 with [Rh(HBim)-(COD)] afforded the heterobinuclear complex [(q6-p-cymene)Ru(acac)@-HBim)Rh(COD)]A (A = C1(7), BF4 (8)). At room temperature the Rh(HBim)(COD) moiety of complexes 7 and 8 rotates rapidly around the RuN bond, but this process stops a t 223 K. [(@-p-cymene)-Ru(acac)Cl] and [(y6-p-cymene)Ru(acac)(PPh3)lBF4 reacted with 2,2'-bibenzimidazole (H2-Bbzim) rendering [(v6-p-cymene)Ru(HBbzim)Cll(9) and [(y6-p-cymene)Ru(HBbzim)(PPh3)IBF~ (101, respectively. Complex 9 undergoes reaction with [M(acac)L21 yielding [(@-p-cymene)-ClRu(p-Bbzim)MLal, (M = Rh; La = COD (n = 1) (ll), norborna-2,ti-diene (NBD) (n = 2) (12), (Cola (n = 2) (13). M = Ir; L2 = COD (n = 1) (14)). The molecular structure of complex 12 has been determined. Crystals are triclinic, space group Pi, with cell parameters a = 12.998(1) A, b = 14.035(1) A, c = 18.081(2) A, a = 79.864(4)", , 8 = 78.046(5)", y = 73.326(7)", and 2 = 2. The compound is tetranuclear with two Bbzim2-ligands bridging the metal atoms. Each Bbzim2-coordinates to the metals in a n unsymmetrical tetradentate manner through its four nitrogen atoms, chelated to the Ru atoms and bonded in a n unidentate manner to the two Rh atoms. The cationic complex 10 undergo reaction with the acetylacetonates [M(acac)L~l yielding the cationic binuclear complexes [ (y6-p-cymene)(PPh3)-Ru@-Bbzim)ML2lBF4 (M = Rh; L2 = COD (15), NBD (16), (C0)2 (17). M = Ir; L2 = COD (18)). Carbonylation of 18 afforded [(y6-p-cymene)(PPh~)Ru(M-Bbzim)Ir(CO)21BF4 (19) and complex 17 could analogously be obtained from complexes 15 or 16. The molecular structure of complex 19 has been determined by diffractometric methods. Crystals are monoclinic, space group P21/c, with cell parameters a = 11.586(2) A, b = 20.489(2) A, c = 17.225(1) A, ,Ll = 95.34(1)", and Z = 4. In the solid state, two complex cations [(y6-p-cymene)(PPh3)Ru-(M-Bbzim)Ir(CO)zl related by a n inversion center are joined by an intermetallic Ir-Ir interaction (3.0808(5) A). The cation consists of a Ru and a n Ir atom connected by a Bbzim2anion that chelates both metals through four nitrogen atoms. Complexes 11, 14, and 15-19 are active catalysts for the homogeneous hydrogenation of cyclohexene. Kinetic studies showed that the reduction catalyzed by 14 is first-order in catalyst concentration and secondorder in hydrogen concentration.
Inorganic Chemistry, 1984
Reaction of [(dipho~)Rh(acetone)~]BF~ with mer,truns-IrHC12L3 (L = PMe2Ph, PEt2Ph, PEt3; diphos = Ph2PCH2CH2PPh2) affords the hydridebridged dinuclear complexes [(diphos)Rh(p-H)(p-Cl)IrCIL,] BF4. Solution studies show that the bridging ligands are only weakly coordinated to the rhodium. The molecular structure of 3 (L = PEt3) has been determined by X-ray diffraction: monoclinic, space group P21/c, 2 = 4, a = 11.786 (2) A, b = 19.673 (4) A, c = 22.571 (4) A, @ = 89.88 (1)O. The structure was solved by Patterson and Fourier methods using 5750 observed reflections [I 2 3u(Z)] and refined to a conventional R = 0.057. The coordination around rhodium is distorted square planar and that around iridium is distorted octahedral. The Rh-Ir distance is 2.903 (1) A, and the bridging chlorine atom is almost symmetrically bonded to the metals (Rh-Cl = 2.386 (3), Ir-CI = 2.381 (3) A). The isoelectronic complex [(diph~s)Rh(p-H)(p-Cl)IrH(PEt,)~]BF~ was obtained in a similar reaction, starting from mer,~is-IrH~Cl(PEt,)~. Its structure determined by X-ray diffraction, as above, is monoclinic, space group P21, Z = 2, a = 11.102 (2) A, b = 13.582 (3) A, c = 16.694 (4) A, @ = 85.06 (2)'. The final agreement factor (for the 4553 observed reflections) R is 0.062. As for compound 3 the coordination around Rh and Ir is distorted square planar and octahedral, respectively. There is a pronounced asymmetry in the chlorine bridge (Rh-Cl = 2.394 (5), Ir-Cl = 2.510 (5) A), and the metal-metal separation is 2.969 (2) A. t o the synthesis of cationic Rh(1)-Ir(II1) complexes. Experimental Section All operations were carried out under purified nitrogen. Solvents were distilled under nitrogen and dried prior to use. Elemental analyses were formed by the Microanalytical Section of the Swiss Federal Institute of Technology. Infrared spectra in the region 4000-400 cm-' were recorded on a Beckman IR 4250 spectrophotometer as KBr pellets or Nujol mulls. The IH and 31P{'HJ NMR spectra were recorded at 90.00 and/or 250.00 and 36.43 MHz, respectively, on a FT Bruker WH-90 or F T Bruker 250 instrument. 'H and chemical shifts are given relative to external (CH3)$i and H3P04, respectively. A positive sign denotes a shift downfield of the reference. A. Syntheses. [Rh(dipho~)(nbd)]BF,~ (nbd = norbornadiene), mer,truns-IrHCl2L3 (L = PMe2Ph, PEt2Ph, PEt3),9 and mer,cis-IrHCl2(PMePh2),,Io were prepared according to literature methods. For the preparation of mer,cis-IrH,CI(PEt,),, a toluene solution of [ (~o c)~I r C l ]~ (coc = cyclooctadiene) was reacted with 3 equiv of PEt,, and hydrogen was bubbled through the solution for 10 min, leading almost quantitatively to the product. (a) ETH-Zcntrum. (b) Taken in Dart from the Ph.D. thesis of H.L. (c)
Inorganic Chemistry, 1984
Reaction of [(dipho~)Rh(acetone)~]BF~ with mer,truns-IrHC12L3 (L = PMe2Ph, PEt2Ph, PEt3; diphos = Ph2PCH2CH2PPh2) affords the hydridebridged dinuclear complexes [(diphos)Rh(p-H)(p-Cl)IrCIL,] BF4. Solution studies show that the bridging ligands are only weakly coordinated to the rhodium. The molecular structure of 3 (L = PEt3) has been determined by X-ray diffraction: monoclinic, space group P21/c, 2 = 4, a = 11.786 (2) A, b = 19.673 (4) A, c = 22.571 (4) A, @ = 89.88 (1)O. The structure was solved by Patterson and Fourier methods using 5750 observed reflections [I 2 3u(Z)] and refined to a conventional R = 0.057. The coordination around rhodium is distorted square planar and that around iridium is distorted octahedral. The Rh-Ir distance is 2.903 (1) A, and the bridging chlorine atom is almost symmetrically bonded to the metals (Rh-Cl = 2.386 (3), Ir-CI = 2.381 (3) A). The isoelectronic complex [(diph~s)Rh(p-H)(p-Cl)IrH(PEt,)~]BF~ was obtained in a similar reaction, starting from mer,~is-IrH~Cl(PEt,)~. Its structure determined by X-ray diffraction, as above, is monoclinic, space group P21, Z = 2, a = 11.102 (2) A, b = 13.582 (3) A, c = 16.694 (4) A, @ = 85.06 (2)'. The final agreement factor (for the 4553 observed reflections) R is 0.062. As for compound 3 the coordination around Rh and Ir is distorted square planar and octahedral, respectively. There is a pronounced asymmetry in the chlorine bridge (Rh-Cl = 2.394 (5), Ir-Cl = 2.510 (5) A), and the metal-metal separation is 2.969 (2) A. t o the synthesis of cationic Rh(1)-Ir(II1) complexes. Experimental Section All operations were carried out under purified nitrogen. Solvents were distilled under nitrogen and dried prior to use. Elemental analyses were formed by the Microanalytical Section of the Swiss Federal Institute of Technology. Infrared spectra in the region 4000-400 cm-' were recorded on a Beckman IR 4250 spectrophotometer as KBr pellets or Nujol mulls. The IH and 31P{'HJ NMR spectra were recorded at 90.00 and/or 250.00 and 36.43 MHz, respectively, on a FT Bruker WH-90 or F T Bruker 250 instrument. 'H and chemical shifts are given relative to external (CH3)$i and H3P04, respectively. A positive sign denotes a shift downfield of the reference. A. Syntheses. [Rh(dipho~)(nbd)]BF,~ (nbd = norbornadiene), mer,truns-IrHCl2L3 (L = PMe2Ph, PEt2Ph, PEt3),9 and mer,cis-IrHCl2(PMePh2),,Io were prepared according to literature methods. For the preparation of mer,cis-IrH,CI(PEt,),, a toluene solution of [ (~o c)~I r C l ]~ (coc = cyclooctadiene) was reacted with 3 equiv of PEt,, and hydrogen was bubbled through the solution for 10 min, leading almost quantitatively to the product. (a) ETH-Zcntrum. (b) Taken in Dart from the Ph.D. thesis of H.L. (c)
Synthesis and characterization of new pentamethylcyclopentadienyl iridium hydride complexes
Journal of Organometallic Chemistry, 2012
Pentamethylcyclopentadienyl iridium dihydride complexes [Cp*Ir(H) 2 (PR 3 )]; (PR 3 ¼ PPh 2 Me, PTA) were prepared by reaction of [Cp*IrCl 2 (PPh 2 Me)] and [Cp*IrCl 2 (PTA)], respectively, with an excess of sodium bis(2-methoxyethoxy)aluminium hydride (Red-Al). Protonation of the dihydride [Cp*Ir(H) 2 (PPh 2 Me)] with HBF 4 $Et 2 O at low temperature gave the classical trihydride complex [Cp*Ir(H) 3 (PPh 2 Me)]BF 4 that displays quantum mechanical exchange coupling. Reaction of [Cp*IrCl 2 (PPh 2 Me)] with CO gave the halfsandwich iridium carbonyl compound [Cp*IrCl(CO)(PPh 2 Me)]Cl which, by reaction with NaBPh 4 , yielded yellow microcrystals of [Cp*IrCl(PPh 2 Me)(CO)]BPh 4 adequate for X-ray diffraction analysis.
ACS omega, 2020
The Ir III hydrido complexes [1] and [2] have been synthesized by the regioselective oxidative addition of the N7−H bond of 8-halogenotheophyllines to [IrCl(coe) 2 ] 2 in the presence of PPh 3. The use of dppf in this reaction yielded the bimetallic Ir III / Fe II hydrido complexes [3] and [4]. X-ray diffraction studies confirmed that complexes [1]−[4] feature a theophyllinato ligand coordinated to the metal center in the rarely observed, chelating fashion via the N7 and O1 atoms. In addition, 8-bromoadenine reacts with [IrCl(coe) 2 ] 2 in the presence of PPh 3 to form the Ir III hydrido complex [5] which features one anionic 8-bromoadeninato and one neutral 8-bromoadenine ligand linked by an intramolecular hydrogen bond. Complex [5] was characterized by highresolution mass spectrometry and an X-ray diffraction analysis but could not be analyzed by nuclear magnetic resonance spectroscopy because of its low solubility.
Inorganic Chemistry, 1997
The organohydrazide chelate complexes M III (NNpy)(PPh 3 ) 2 Cl 2 (1, 3) (M ) Re, Tc) have been synthesized using the organohydrazine 2-hydrazinopyridine. The chelated organohydrazide is a diazenido(1-) ligand that forms a five-membered ring with the metal center. An X-ray structural analysis of 1 indicates that there is a delocalized π-system formed by the chelate ring. These octahedral, d 4 metal complexes have diamagnetic 1 H NMR spectra. Complex 1, C 41.50 H 34 Cl 2 N 3 O 0.5 P 2 Re, crystallizes in the triclinic space group P1 h with a ) 10.5549 Å, b ) 12.2699(8) Å, c ) 16.8206(12) Å, R ) 105.9050(10)°, ) 95.8930(10)°, γ ) 111.0100(10)°, V ) 1906.1(2) Å 3 , Z ) 2, and R ) 0.0650 based on 5268 unique reflections. The FABMS+ in (p-nitrobenzyl alcohol) of 3 reveals a parent ion peak at m/z 799.2. The complex [Re(HNNpy)(NNpy)(PMe 2 Ph) 2 Cl] + [Cl] -(2) contains a chelated, neutral organodiazene ligand and a linear, diazenido(1-) ligand. The X-ray structural analysis of 2, C 26 H 30 -Cl 2 N 6 P 2 Re, indicates a delocalized π-system formed by the chelate ring. The 1 H NMR spectrum of 2 is not paramagnetically shifted. Complex 2 crystallizes in the orthorhombic space group Pna2 1 with a ) 17.383(4) Å, b ) 13.967(3) Å, c ) 12.002(2) Å, V ) 2913.9(10) Å 3 , Z ) 4, and R ) 0.0384 based on 3083 unique reflections.
Journal of the Brazilian …, 2006
Dois novos complexos zwitteriônicos de oxorrênio(V), [ReOCl 2 (Hdhp)(PPh 3)] (1) e [ReOBr 2 (Hdhp)(PPh 3)] (2) (H 2 dhp = 2,3-dihidroxipiridina), foram sintetizados e caracterizados por espectroscopia de absorção no infravermelho, ressonância magnética nuclear de 1 H e 31 P, análise elementar e determinação da estrutura cristalina e molecular por difração de raios X em monocristais. Os complexos apresentam geometria de coordenação octaédrica bastante distorcida, com os dois ligantes haletos arranjados em posições cis equatoriais, o ligante trifenilfosfina em posição trans a um dos haletos e o ligante Hdhpcoordenado de forma bidentada através de seus átomos de oxigênio, sendo um em posição trans ao ligante oxo e o outro em posição trans com relação ao outro haleto. Este ligante tem seu átomo de nitrogênio protonado. Os compostos 1 e 2 apresentam empacotamento cristalino bastante diferente, influenciado em ambos os casos por ligações de hidrogênio intermoleculares dos tipos N-H⋅⋅⋅X (X = Cl, Br) e N-H⋅⋅⋅O. Two novel zwitterionic oxorhenium(V) complexes, [ReOCl 2 (Hdhp)(PPh 3)] (1) and [ReOBr 2 (Hdhp)(PPh 3)] (2) (H 2 dhp = 2,3-dihydroxypyridine), were synthesized and characterized by infrared spectroscopy, 1 H and 31 P nuclear magnetic resonance, elemental analysis and crystal and molecular structure determination by X-ray diffraction on single crystals. Both complexes show distorted octahedral coordination geometry, with the halide ligands arranged in equatorial cis positions, the triphenylphosphine ligand in a trans position to one of the halides and the Hdhpligand coordinated in a bidentate form through its oxygen atoms, one in trans position to the oxo-ligand and the other in trans position to the second halide. The nitrogen atom of this ligand is protonated. Compounds 1 and 2 show quite different crystal packing, both influenced by hydrogen bonds of the types N-H⋅⋅⋅X (X = Cl, Br) and N-H⋅⋅⋅O.