Iridium complexes tetrahedral

Thus the Berry coordinate represents a viable option for intramolecular exchange in rhodium and iridium complexes, in contrast to platinum and palladium complexes. Nickel complexes, on the other hand, can adopt either tetrahedral or square-planar conformations in the four-coordinate structures, and therefore the fact that these complexes can take on any of the three conformations is not surprising. This analysis is described in detail in Reference 67. 

For tetranuclear cluster complexes, three stmcture types are observed tetrahedral open tetrahedral (butterfly) or square planar, for typical total valence electron counts of 60, 62, and 64, respectively. The earliest tetracarbonyl cluster complexes known were Co4(CO)22, and the rhodium and iridium analogues. The... 

There appear to be no reports of an analogous reaction involving [Rh-(CO)4] , but Schmid has described the reaction between BiCl3 and Na[Ir-(CO)4], which affords the tetrahedral cluster [BiIr3(CO)9], 138 (137). Complex 138 (see Fig. 38) contains only terminal carbonyls, and an iridium... 

Tables 1 and 2 gives the numerical data for a series of vanadium (II), chromium (III), manganese (IV), molybdenum (III), rhenium (IV), iridium (VI), cobalt (II), and nickel (II) complexes. The first spin-allowed absorption band, caused by an internal transition in the partly filled shell, has the wavenumber equal to A. If spin-forbidden transitions are superposed on this band, a certain distortion from the usual shape of Gaussian error curve can be observed, and one takes the centre of gravity of intensity as the corrected wavenumber ai. One has to be careful not to confuse electron transfer or other strong bands with the internal transitions discussed here. Obviously, one has also to watch for absorption due to other coloured species, produced e. g. by oxidation or hydrolysis of the solutions. In the case of certain octahedral nickel (II), and nearly all tetrahedral cobalt (II) complexes, the first band has not actually been...

Tetrahedral perchlorate ion, [C104] , is an uncommon ligand.1 The molecular perchlorato complexes of iridium and rhodium2 described here are thus of inherent interest as such, but their principal importance lies in their versatile reactivity. These compounds undergo addition, substitution, and addition-substitution reactions with many molecules and ions.3 In particular, the latter conversions lead to a remarkable number of cationic d8 complexes of these metals, which offer themselves as a unique series for a study of the electronic properties of a variety of molecules as ligands (L).3 Not less significant are the substitution reactions in which the perchlorate ligand is replaced by other unusual anions.4... 

Iridium(— I).—The preparation and properties of a large number of [M(NO)L3] complexes have been reported, including [Ir(NO)(PPh3)3]. Their v(NO) frequencies suggest that they are complexes, while n.m.r. data are consistent with the pseudo-tetrahedral structure (26 M = Ir) rather than the... 

The period under discussion has seen intense interest in the recently discovered i7 -H2 complexes. The relevance of these to some isomerization reactions of square-planar complexes was reported in Volume 5 of this series, and is covered in another recent review. " More of these fluxional ds-dihydridoplatinum compounds have been reported, and the role of 17 -H2 derivatives in oxidative additions to d rhodium(I) and iridium(I) has been discussed. The increasing role of theoretical and bonding studies is reflected in four works relevant to 4-and 5-coordinate molecules. Electronic structure is related to chemical reactivity in the reactions of phosphine bases with d bis(l,l-dithiolato)platinum com-plexes. Huckel calculations on the reactions of bis(nitrogen donor) ligands with 16-electron platinum(II) complexes have been carried out, as has more work on symmetry selection rules for isomerization reactions, which includes pseudorotation of 5-coordinate complexes and square-planar to tetrahedral conversions of 4-coordinate molecules. ... 

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