403824-29-3Relevant articles and documents
Chloride Transfer across the Liquid-Liquid Interface Facilitated by a Mo
Suzuki, Takayoshi,Kashiwamura, Shinsaku,Kashiwabara, Kazuo
, p. 2349 - 2360 (2001)
A series of new cobalt(III) phosphine complexes of trans-[Co(dtc)2(PMe3-nPhn)2]BF4 (dtc = N,N-dimethyldithiocarbamate; n = 0, 1, 2 or 3) and cis-[Co(dtc)2(PMe3 or PMe2Ph)2](BF4 or PF6) have been prepared and their crystal structures and spectroscopic properties have been investigated. It is found that the Co-S bond lengths vary with steric and electronic factors of the P-ligands; i.e. (1) the intramolecular ?-? stacking interaction between the dtc plane and the phenyl ring of the P-ligand, and (2) the electronic trans influence of the trans-positioned P-ligand. The strength of electronic trans influence decreases as PMe3 > PMe2Ph > P(OCH2)3CEt in accordance with the order of ?-donicity strengths. In the series of trans-isomers, the electronic trans influence is competitive with the steric requirement of the phosphine to elongate the mutually trans Co-P bonds. The steric trans influence via the equatorial dtc ligands for such an elongation of the Co-P bonds seems to be negligible, which is in sharp contrast to the situation for via pentane-2,4-dionate (acac) ligands in the analogous complexes, trans-[Co(acac)2(PMe3-nPhn)2]PF6. This is probably due to the compactness of dtc and the resulting open space at the Co atom. The fact that the Co-P bond lengths in the dtc complexes are shorter than those in the acac complexes is reflected in the larger stability toward hydrolysis of the dtc complexes. In the UV-vis absorption spectra, the degenerate splitting component (a1Eg) of the first d-d transition band of trans-[Co(dtc)2(PMe3-n-Phn)2]+ is observed at almost the same position (within 300 cm-1) as that of the corresponding acac complexes, while the transition energies of the P-to-Co LMCT of these two series of complexes are rather different (at least 2700 cm-1) from each other. Furthermore, the first and the second d-d transition bands of cis-[Co(dtc)2(PMe3 or PMe2Ph)2]+ are observed at lower energy than those of cis-[Co(dtc)2{P(OMe)3}2]+ in spite of a weaker ?-donor of phosphite. The separation of the first and the second d-d transition bands of the P(OMe)3 complex is remarkably smaller than the separation of the bands of the PMe3 one, being indicative of a further reduction of the interelectronic repulsion in the P(OMe)3 complex.
