Rhodium complexes carbonyls

Trls(diphenylthiophosphinoyl)nethanide (C(P(S)Ph2)3 ) complexes of rhodium and Iridium have been prepared and the crystal structure of the iridium complex [Ir(co) 2 T)2-C(P(S)Ph2 3-S,S ] reveals a bidentate S,S ligand-iridium interaction. The trihydride complex [IrHa(CO)(dppe)] reacts with primary, secondary, and tertiary silanes to yield mono- and bis(silyl)hydride complexes of the formulae [IrH2(SiRR 2) (CO)(dppe)] and [IrH(SiRR 2)2(CO)(dppe)] (SiRR 2 = SiPhs, 

A novel one-dimensional polymer [(Cu(bpen)(CO)(CH3CN)(PFe) ] (bpen B trans-i,2-bis(2-pyrldyl)ethylene) has been synthesized from [Cu(CH3CN)4][PFe] and CO in HeOH. This polymer has been characterized by X-ray diffraction and shows a tetrahedral form of Cu(l) with a single CO ligand with a short C-0 bond 

Gamasa, J. Glmero, E. Lastra, S. Garcla-Granda, and D. Moreiras, J.Ghem.Soc., Dalton Trans., 1991, 1557. 

Szymonlak, N.H. Kublckl, J. Besan on, and C. Moise, Inorg.Ghim.Acta, 1991, 180, 153. 

Layher, W. HOnle, and H.G. van Schnering, Z.Anorg.Allg.Ghem., 1991, 595, 67. 

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The less bulky ligand (71) studied by Gladfelter leads to dimeric complexes [Rh2(71)2(CO)2] and even tetramers.222 Transformations of rhodium carbonyl complexes in alkene hydroformylation are discussed from the standpoint of the catalytic system self-control under the action of reaction... 

The trend towards higher linearities breaks down at two instances one involves a rather bulky ligand with a 0-value of 190°, the other one involves hexafluoroisopropyl phosphite that has a very high %-value. Both give rise to unstable rhodium carbonyl complexes either for steric reasons (vide infra) or for electronic reasons. The %-value of hexafluoroisopropyl phosphite is very high indeed and it is thought that this value of 51 means that electronically it is very similar to CO, i.e. a strong electron acceptor. Hence, the propensity of its... 

Figure 7.2 Model rhodium carbonyl complexes supported on silica.

Facile formation of metal carbonyl complexes makes rhodium a very useful catalyst for both the hydroformylation of multiple bonds and the decarbonylation of the aldehydes. Two groups have independently utilized rhodium carbonyl complex obtained from decarbonylation of aldehydes in PKR (Scheme 5). 

Ojima has reported that a number of mono- and polynuclear rhodium carbonyl complexes catalyze the cyclization/... 

Gyclization/hydrosilylation of enynes catalyzed by rhodium carbonyl complexes tolerated a number of functional groups, including acetate esters, benzyl ethers, acetals, tosylamides, and allyl- and benzylamines (Table 3, entries 6-14). The reaction of diallyl-2-propynylamine is noteworthy as this transformation displayed high selectivity for cyclization of the enyne moiety rather than the diene moiety (Table 3, entry 9). Rhodium-catalyzed enyne cyclization/hydrosilylation tolerated substitution at the alkyne carbon (Table 3, entry 5) and, in some cases, at both the allylic and terminal alkenyl carbon atoms (Equation (7)). 

Shibata and co-workers have reported an effective protocol for the cyclization/hydrosilylation of functionalized eneallenes catalyzed by mononuclear rhodium carbonyl complexes.For example, reaction of tosylamide 13 (X = NTs, R = Me) with triethoxysilane catalyzed by Rh(acac)(GO)2 in toluene at 60 °G gave protected pyrrolidine 14 in 82% yield with >20 1 diastereoselectivity and with exclusive delivery of the silane to the G=G bond of the eneallene (Equation (10)). Whereas trimethoxysilane gave results comparable to those obtained with triethoxysilane, employment of dimethylphenylsilane or a trialkylsilane led to significantly diminished yields of 14. Although effective rhodium-catalyzed cyclization/hydrosilylation was restricted to eneallenes that possessed terminal disubstitution of the allene moiety, the protocol tolerated both alkyl and aryl substitution on the terminal alkyne carbon atom and was applicable to the synthesis of cyclopentanes, pyrrolidines, and tetrahydrofurans (Equation (10)). 

Rhodium carbonyl complexes catalyze the silane-initiated cascade cyclization of 1,6,11-triynes to form fused aromatic tricyclic compounds. For example, reaction of 83 [X = G(G02Et)2] with methyldiphenylsilane catalyzed by the tetrarhodium carbonyl cluster Rh4(GO)i2 in toluene at room temperature gave an 88 12 mixture of the silylated and unsilylated fused tricycles 84a and 84b [X = G(G02Et)2] in 85% combined yield (Equation (55)). The ratio of silylated to unsilylated tricyclic product formed in the reaction of 1,6,11-triynes was dependent on the nature of the substrate (Equation (55)). For example, Rh4(GO)i2-catalyzed reaction of diaminotriyne 83 (X = NBn) with methyldiphenylsilane gave unsilylated tricycle 84b (X = NBn) in 92% yield as the exclusive product (Equation (55)). 

Rhodium carbonyl complexes also catalyze the cascade cyclization/hydrosilylation of 6-dodecene-l,l 1-diynes to form silylated tethered 2,2 -dimethylenebicyclopentanes. For example, reaction of ( )-85 with dimethylphenylsilane catalyzed by Rh(acac)(CO)2 in toluene at 50 °G under GO (1 atm) gave 86a in 55% yield as a single diastereomer (Equation (56)). Rhodium-catalyzed caseade cyclization/hydrosilylation of enediynes was stereospecific, and reaction of (Z)-85 under the conditions noted above gave 86b in 50% yield as a single diastereomer (Equation (57)). Rhodium(i)-catalyzed cascade cyclization/hydrosilylation of 6-dodecene-1,11-diynes was proposed to occur via silyl-metallation of one of the terminal G=G bonds of the enediyne with a silyl-Rh(iii) hydride complex, followed by two sequential intramolecular carbometallations and G-H reductive elimination. ... 

Carbonylation of 2,3-homo-l//-azepines has been effected by means of their metal and carbonyl complexes and provides a useful route to a variety of isomeric azabicyclo-nonadienones. For example, the tricarbonyliron complex with carbon monoxide at 80 °C and 160 atm yields the 9-oxo-2-azabicyclo[3.3.l]nona-3,7-diene (167) (57%) or the 9-oxo-2-azabicyclo[3.2.2]nona-3,6-diene (168) (60%) depending on the exo or endo configuration of the tricarbonyliron complex. A third isomer, namely ethyl 7-oxo-9-azabicyclo[4.2.1]nona-2,4-diene-9-carboxylate (169), is formed on heating (125 °C) the azepine with carbon monoxide under pressure in the presence of the rhodium carbonyl complex [Rh(CO)Cl2] (78CB3927). 

Under mild conditions, hydroformylation of olefins with rhodium carbonyl complexes selectively produces aldehydes. A one-step synthesis of oxo alcohols is possible using monomeric or polymeric amines, such as dimethylbenzylamine or anion exchange resin analog to hydrogenate the aldehyde. The rate of aldehyde hydrogenation passes through a maximum as amine basicity and concentration increase. IR data of the reaction reveal that anionic rhodium carbonyl clusters, normally absent, are formed on addition of amine. Aldehyde hydrogenation is attributed to enhanced hydridic character of a Rh-H intermediate via amine coordination to rhodium. 

Bidentate phosphorus-nitrogen ligands, in rhodium carbonyl complexes, 7, 132... 

Polynuclear Rhodium Carbonyl Complexes and Their Relationships to Mononuclear and Binuclear Rhodium Carbonyl Complexes1... 

Another simple rhodium carbonyl complex also known to be Involved In the fragmentation and aggregation reactions of clusters Is Rh2(C0)s This species has been shown to participate In the reactions of neutral rhodium carbonyl species In either matrixes or solutions (equation 4), but It has not yet been Implicated In the chemistry of large anionic clusters. 

Our Interest In understanding the behavior of rhodium carbonyl clusters in systems which catalytlcally convert CO H2 Into alcohols 3. prompted us to test the potential presence of mononuclear and bI nuclear rhodium carbonyl complexes In these systems. A positive characterization of these species under these circumstances would show a previously unknown behavior of rhodium carbonyl clusters under high pressure of carbon monoxide. It could also show the existence of a parallel behavior between the chemistry of these species under ambient and high pressures of carbon monoxide, and it may shed some light on the catalytic reactions occurring in those systems. 3. ... 

It was of interest in this respect to determine which rhodium carbonyl complexes result from the former reaction and whether the parallel formation of any organic products derived from the hydrogenation of carbon monoxide Is also occurring. The latter possibility was considered because of the presence of hydrides In the cluster and the involvement of hydrido carbonyl complexes in the hydrogenation of carbon monoxide. Unfortunately, It was not possible to detect any organic products formed from this reaction even after the cyclic repetition of the transformations below (equation 14). 

The conditions and experimental procedures used to study the fragmentation of CRhi782(60)32 are the same as those described above. Once more, it has been established that Rh2(C0)g is produced under high pressure, but in this instance it has been possible to detect the presence of another rhodium carbonyl complex with Infrared absorptions at 2010, 1970 cm"1. This pattern has been assigned to ERh(C0)2(SH)]2 ... 

Another simple rhodium carbonyl complex that has been shown to be involved in the aggregation and fragmentation reactions of polynuclear rhodium species is "Rh(C0)2+ ". This moiety has been shown to be involved in such reactions under ambient conditions as reported by Chinl, et al. UJ (equations 21 and 22). 

These studies have Indicated that simple rhodium carbonyl complexes, e.g., mono- and binuclear species are Involved in the fragmentation and aggregation reactions of rhodium carbonyl clusters under high pressures of carbon monoxide and hydrogen. They indicate that it is possible to write formal equations for such reactions in the case of rhodium carbonyl anionic hydrido clusters (equation 25) and for the more particular situation when there are not hydrides present (equation 26)... 

Facile reduction of C02 was found by rhodium compounds. Svoboda and Mctflcjs studied the reaction of chlorotris(triphenylphosphine)rhodium and CO2 in the presence of the organosilicon hydrides Et3SiH or HSi(OEt)3 (287,288). They observed the formation of the rhodium-carbonyl complex RhCI(CO) (PPh ), althougli attempts at isolating the analogous RuCl(CO)(PPh,>2 were... 

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