Carbonyl complexes of noble metals with halide ligands

Isolation and characterization of an iodide bridged dimeric palladium complex in carbonylation of methanol

“…2(b) and (d)). In presence of carbon monoxide, the dimeric anionic species [Pd 2 I 6 ] 2À was converted to the monomeric palladium species [PdI 3 CO] À , as evidenced by IR spectroscopic analysis at room temperature, which showed a strong carbonyl frequency at 2094 cm À1 , consistent with the literature [10] (see Supplementary material, Figure 1). …”

Carbide complexes as π-acceptor ligands

“…The existence of carbonyl analogues to 3, 4, 5, 6, 11, and 12 provides for such a comparison, and suggests that the RuC and CO moieties play the same role in the respective complexes. The availability of X-ray crystal structures of [RhCl(CO) 2 ] 2 , 60 [IrCl(CO) 3 ], 61 (Bu 4 N)[PdCl 3 (CO)], 62 (Bu ¼ butyl) (Bu 4 N)[PtCl 3 -(CO)], 63 and [AuCl(CO)] 64 allows a direct comparison of the geometries of the carbonyl complexes and the structures of 1-12 (Table 3), and here it is relevant to note that 3 and 4 further allow a comparison of the RuC and CO ligands within the same complex. Though Au(CO) 2 + is well established, [65][66][67][68] its crystal structure has not been reported.…”

Palladium carbonyl complexes

“…Complex 51 has been obtained by treating a solution of (NBu n 4 (PdBr 3 ) in ttetrachloroethane with CO (P CO = 1 atm). 163 The carbonylation of PdBr 2 (P CO > 70 atm) leads to the formation of Pd 2 (CO) 2 Br 4 , which, judging from the IR spectra (n CO = 2145 cm 71 ), is constructed similarly to complex 49. The iodide analogue of complex 49 could not be obtained.…”

“…The stability of the palladium carbonyl halide complexes (both neutral and anionic) decrease in the sequence Cl > Br > I. 163 The study of the kinetics of the exchange of the carbonyls in the carbonyl halides between [M( 13 CO)X 3 ] 7 and 12 CO (IR and 13 C NMR spectroscopy) showed that the carbonyl ligands in these complexes are bound fairly strongly and that the rate of exchange of the carbonyls is lower almost by six orders of magnitude than the rate of exchange of ethene in the analogous ethene p-complexes. 164 The formation of complex 49 in thionyl chloride has been investigated and the thermodynamic constants of the process have been determined, which made it possible to estimate the energy of the Pd ± CO bond (* 24 kcal mol 71 ).…”

“…164 The formation of complex 49 in thionyl chloride has been investigated and the thermodynamic constants of the process have been determined, which made it possible to estimate the energy of the Pd ± CO bond (* 24 kcal mol 71 ). 163 Analysis of the thermodynamic and spectroscopic data led to the conclusion 155,165 that the contribution of metal-to-ligand the p-back-donation in the palladium carbonyls is slight and that the strength of the Pd ± CO bond is determined almost exclusively by the s-donor capacity of the carbonyl ligand.…”