Carbonyl complexes structural properties

A number of MO calculations have been performed on carbonyl complexes, with methods ranging from ab initio to DVM-HFS. In any case it was found that both a donation and jr back-donation interactions are important in determining the geometrical structure and physical properties of these complexes. The ab initio calculations of Sakaki et al.110 have shown that the strengthening of jt back-donation is the driving force which stabilizes the pseudotetrahedral geometry vs. the square planar one in [Ni(PR3)2(CO)2] complexes. 

The structures and properties of the binary (homoleptic) carbonyl complexes of the transition elements, including representative synthetic routes... 

Some iron and nickel cyanide and carbonyl complexes have been reported as models of the [FeNi]-hydrogenase enzymes. The preparation and structures of the trigonal bipyramidal nickel and iron complexes with the tetradentate ligands tris(2-phenylthiol)phosphine (PS3) and tris(3-phenyl-2-thiophenyl)phosphine (PS3 ) have been reported [70, 71]. The nickel carbonyl complex [Ni(PS3 )(CO)] exhibits vco at 2029 cm compared with the value of 1940 em" for the iron earbonyl complex [Fe(PS3 )(CO)]. Both of these complexes lose CO upon oxidation. The use of cyanide in place of carbon monoxide allows for the preparation of both [Fe (PS3)(CN)] and [Fe (PS3 )(CN)] eomplexes. The IR properties of... 

Rationalization, let alone a priori prediction, of these results based on common structural models is not a trivial issue. In order to address such problems one needs a better understanding of the energetics and conformational properties of Lewis acid carbonyl complexes. The aim of this chapter is to survey the lit-... 

Binuclear carbonyl complexes with M—M bond analogous to Mn2(CO)io have been prepared for technetium and rhenium. The rhenium analogue has been synthesized by the carbon monoxide reduction of Rc207 or KRe04 (eq (5)) [3] or by reduction of anhydrous Re(III) or Re(V) chloride by sodium under CO pressure (eq (6)). [15]. The physical and structural properties of Tc2(CO),o and Re2(CO)io are listed in Table 9.1. 

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