CpRh

Both T)5-CpCo(Me2C2B2Me2CH2) and r -CpRh(Et2C2B2Et2CHMe) have been used to synthesize special 2,3-dihydro-1,3-diborole sandwich compounds. Via the anions [i7 -CpM(R2C2B2R 2CR")] , available by reduction with K, the AuPPhj derivatives are obtained ... 

One specific advantage of the frozen noble gas is that it does not absorb IR and thus it is possible, in principle, to examine the spectrum of any coordinated ligand within the matrix. In practice, it is more difficult because, although the intensity of v(N-N) and V(N-O) bands are comparable with V(C-O) bands, most of the vibrations of other ligands give rather weak IR bands. However, as an example, in recent important work, Perutz (8) has demonstrated that photolysis of CpRh(C2H ) in Ar matrices at 20K leads to reversible loss of C2H to form CpRh(C2H ) identified by IR... 

Cyclopentadienyl rhodium silyl derivatives include Cp Rh(H)2(SiEt3)2, which has been used as a precursor to heterometallic clusters.257 The photolysis of CpRh(PPh3)(7]2-C2H4) with SiHR3 (R = Et, Pr1) results in oxidative... 

These Rh complexes have been the subject of intense interest due to their propensity for C-H activation of alkanes (Section 3.3.2.7). The noble gas complexes [CpRh(CO)L] and [Cp Rh(CO)L] (L = Kr, Xe) have also been studied in supercritical fluid solution at room temperature [120]. For both Kr and Xe, the Cp complex is ca. 20-30 times more reactive towards CO than the Cp analogue. Kinetic data and activation parameters indicated an associative mechanism for substitution of Xe by CO, in contrast to Group 7 complexes, [CpM(CO)2Xe] for which evidence supports a dissociative mechanism. 

The rhodium complex [CpRh(bipy)Cl2] is reported (162) to act as one-half of a redox couple that, in concert with a manganese porphyrin system, catalyzes the epoxidation of olefins by dioxygen. In this two-phase system, the aqueous phase contains sodium formate, and the organic phase is a trichloroethane solution of [Mnm(tpp)]1+ and the rhodium complex (tpp = meso-tetraphenylporphyrin). Apparently, the rhodium complex catalyzes the reduction of [Mnin(tpp)]1+ by formate, and the manganese(II) species thus formed binds dioxygen and reacts with the substrate olefin to form the epoxide. However, the intermedi-... 

Analogous ligand exchange reaction of cis- and Pww-Feist s esters with the dirhodium complex [/i-ClRh(ethylene)2]2 in pentane gave the corresponding Feist s esters rf-complexes [/(-ClRhL, (L = cF, tF) (equation 310). Further reaction of the latter complex [p-ClRhL2]2 (L = tF) with cyclopentadienylthallium (CpTl) in CH2C12 afforded the monorhodium complex CpRh(tF)2, and reaction with a mixture of both CpTl and dirhodium... 

Duckett and Perutz have shown the stoichiometric reaction of the CpRh(C2H4)(SiR3)H (R = Et, i-Pr) complexes (Scheme 33)201. These complexes have been found to act as precursors to the catalytically active species for the hydrosilylation of ethene with Et3SiH but are not within the catalytic cycle. The mechanism proposed in Scheme 34 for the hydrosilylation of ethene was found to be equivalent to the Seitz-Wrighton hydrosilylation mechanism catalyzed by cobalt carbonyls complexes202. 

Substituted cycloocta-1, 5-diene complexes of CpCO and CpRh. (MW). 

NMR spectroscopic studies show that dienone complexes [M = Fe(CO)3] are protonated at oxygen (171,172). Protonation of 56 [M = CpRh, Cplr] takes place at carbon, yielding 57 (208) [Eq. (28)]. 

Synthesis of the pale yellow dimer [Rh2 P(OMe)3 8] has been reported via ligand displacement from [CpRh(C2H4)2] (Cp = cyclopentadienyl) using excess P(OMe)3 at 60°C.115 Its 31P n.m.r. spectrum at room temperature indicates the non-fluxional bicapped trigonal antiprismatic structure (26). However, at 100 °C the spectrum is... 

Two E2 units may connect two metal centers (123 Table XXXI). These compounds resemble trans-E4M2 octahedra with two E-E bonds broken (or weakened) in the final product. To date the observed molecules are all made of metal fragments that have either 13 or 14 valence electrons. Unfortunately, the structure of Cp Fe 2(P2)2 was disordered, making its detailed comparison with the other examples difficult. The Nb compound has also not been structurally characterized, but the Cp Nb(CO)2 fragment is isoelectronic to the CpCo and CpRh units so that it would be expected to adopt a similar arrangement. 

Lo HC, Leiva C, Buriez O, Kerr JB, Olmstead MM, Fish RH (2001) Bioorganometallic chemistry. 13. Regioselective reduction of NAD+ models, 1-benzylnicotinamide triflate and P-nicotinamide ribose-5 -methyl phosphate, with in situ generated [CpRh(Bpy)H]+ structure-activity relationships, kinetics, and mechanistic aspects in the formation of the 1,4-NADH derivatives. Inorg Chem 40 6705-6716... 

Asbury JB, Ghosh HN, Yeston JS, Bergman RG, Lian TQ. Sub-picosecond IR study of the reactive intermediate in an alkane C-H bond activation reaction by CpRh(CO)2. Organometallics 1998 17(16) 3417-3419. 

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