23677-76-1Relevant academic research and scientific papers
Molecular structure and spectroscopic properties of [Co(Me 2dtc)2{(Ph2PO)2BF2}] (Me2dtc = N,N-dimethyldithiocarbamate)
Sakano, Kyohei,Yamaguchi, Syohei,Suzuki, Takayoshi,Sunatsuki, Yukinari,Kojima, Masaaki,Kashiwabara, Kazuo
, p. 122 - 125 (2014)
Oxidation of a blue ethanolic mixture containing Co(BF4) 2·6H2O and PClPh2 by tetramethylthiuram disulfide afforded a red-colored complex having a cis-[CoIII(Me 2dtc)2(P)2] environment (Me2dtc - = N,N-dimethyldithiocarbamate), although the yield was relatively low. Single-crystal X-ray crystallography revealed that the product was [Co(Me2dtc)2{(Ph2PO)2BF 2}] (1), where bis(diphenylphosphinito)difluoroborate was probably formed by hydrolysis of PClPh2 followed by reaction with BF 4- in ethanol. The same complex was also prepared by hydrolysis of cis-[Co(Me2dtc)2(PHPh2) 2]BF4 in a mixture of acetonitrile, methanol and water. The molecular structure and spectroscopic properties of complex 1 were compared with those of the corresponding Ph2POMe complex, cis-[Co(Me 2dtc)2(Ph2POMe)2]BF4.
Synthesis, crystal structures and isomerization kinetics of a series of [Co(dtc)2{P(OMe)3-nPhn}2]+ (n = 0-2) complexes (dtc- = N,N-dimethyldithiocarbamate): role of ?-donicity, ?-acidity, and cone angle of the P-ligands in the trans influence and trans effect
Iwatsuki, Satoshi,Kashiwamura, Shinsaku,Kashiwabara, Kazuo,Suzuki, Takayoshi,Takagi, Hideo D.
, p. 2280 - 2292 (2007/10/03)
A series of geometrical isomers of the new cobalt(III) complexes containing P(OMe)3-nPhn (n = 0, 1 or 2), trans- and cis-[Co(dtc)2{P(OMe)3-nPhn}2]+ (dtc- = N,N-dimethyldithiocarbamate), have been synthesized and the crystal structures and spectrometric properties were obtained. By comparison with reported structures of related [Co(dtc)2(P-ligand)2]+ complexes, it was shown that the Co-P bond lengths in [Co(dtc)2)P-ligand)2]+ were linearly dependent on the Tolman's cone angle, θT, of the P-ligands. On other hand, the Co-P bond lengths as well as the transition energies of the splitting component (1A1g -> a1Eg:D4h) of the first d-d band of trans-[Co(dtc)2(P-ligand)2]= were not linearly dependent on the Tolman's electronic parameter (χ) of the P-ligands. In the trans-isomers, it was found that the mutual electronic trans influence was not significant in the [Co(dtc)2{P(OMe)3-nPhn}2]+ species while it was far more evident in the complexes with strong ?-donating phosphines such as PMe3 and PMe2Ph. A reversible cis-trans inter-conversion was observed for the [Co(dtc)2{P(OMe)3-nPhn}2]+ complexes: cis to trans isomerization was induced by irradiation of light while slow thermal trans to cis isomerization was observed as a dark reaction. Kinetic measurements of thermal trans to cis isomerization reactions revealed that the absorption change with time followed multi-exponential kinetics when no free P-ligand was added to the reaction mixture: by addition of excess amounts of free P-ligand, first-order kinetic traces were observed for all reactions. The apparent first-order rate constants were independent of the concentration of added free ligands for the isomerization reactions of [Co(dtc)2{P(OMe)2Ph}2]+ and [Co(dtc)2{P(OMe)Ph2}2]+, while saturation kinetics were observed for the reaction of [Co(dtc)2{P(OMe)3}2]+: all isomerization involved pre-dissociation of one of the coordinated P-ligands. It was indicated that a significant amount of square pyramidal [Co(dtc)2{P(OMe)3}]+ exists in equilibrium with [Co(dtc)2{P(OMe)3}2]+, while merely a trace amount of such a 5-coordinate species was involved in the reactions of [Co(dtc)2{P(OMe)2Ph}2]+ and [Co(dtc)2{P(OMe)Ph2}2]+. A contradictory phenomenon observed in these complexes, a small static trans influence with a significant kinetic trans effect, was explained by the combination of (1) a lack of strong ?-donicity of P(OMe)3-nPhn and (2) stabilization of the 5-coordinate square-pyramidal geometry through the electron sponge effect by the dtc- ligand.
Chloride Transfer across the Liquid-Liquid Interface Facilitated by a Mo
Suzuki, Takayoshi,Kashiwamura, Shinsaku,Kashiwabara, Kazuo
, p. 2349 - 2360 (2007/10/03)
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.
Syntheses and Crystal Structures of Bis(dimethyldithiocarbamato)-(4,6-diphenyl-4,6-diphosphanonane-1,9-diammonium) cobalt(III) and Chloro(4,9-diphenyl-4,9-diphosphadodecane-1,12-diamine)nickel(II) Complexes
Kashiwabara, Kazuo,Watanabe, Masayuki,Kita, Masakazu,Suzuki, Takayoshi
, p. 1947 - 1953 (2007/10/03)
The reaction of tetramethylthiuram disulfide with a methanol solution containing CoCl2·6H2O and 4,6-diphenyl-4,6-diphosphanonane-1,9-diamine (313NPPN) gave complexes of [Co(dtc)2{rac(P)- or meso(P)-313HNPPNH}]3+ (313HNPPNH=diprotonated form of 313NPPN, dtc=dimethyldithiocarbamate ion). The crystal structure of the perchlorate salt of the meso(P) isomer was determined by X-ray analysis. Crystal data: monoclinic, P21/c, a=10.789(2), b=30.325(9), c=12.888(2) A, β=102.06(1)°, V=4123(1) A3, Dx=1.55 g cm-3, Z=4, and R=0.077 for 3347 reflections. The 313HNPPNH ligand in the complex coordinates to the Co(III) center through two phosphorus atoms as a didentate four-membered chelate ligand. The crystal structure of [Co(dtc)2{NH2(CH2)3P(CH 2OH)(C6H5)}]B(C6H5) 4, which formed as a by-product in the preparation of the above Co(III)-313HNPPNH complexes, was also determined. Crystal data: triclinic, P1, a=13.817(2), b=15.277(3), c=10.737(2) A, α=109.90(1), β=94.14(2), γ=101.00(1)°, V=2068.8(7) A3, Dx=1.31 g cm-3, Z=2, and R=0.053 for 4303 reflections. [NiCl{rac(P)-343NPPN}]PF6 (343NPPN=4,9-diphenyl-4,9-diphosphadodecane-1,12-diamine) was prepared by the reaction of 343NPPN with NiCl2·6H2O, and the crystal structure was determined. Crystal data: monoclinic, P21/n, a=8.367(2), b=24.058(2), c=13.988(2) A, β=106.17(1)°, V=2704(1) A3, Dx=1.54 g cm-3, Z=4, and R=0.053 for 3043 reflections. The geometry of the complex is a distorted square pyramid with a chloride ion at the apical position, and the 343NPPN ligand functions as a tetradentate chelate ligand.
