Molecular structure and spectroscopic properties of [Co(Me2dtc)2{(Ph2PO)2BF2}] (Me2dtc = N,N-dimethyldithiocarbamate)

• This is the first example of cobalt(III) complex containing an anionic (Ph2PO)2BF2− ligand.
• This is also a rare example of bis(phosphinito)borate complexes determined by the single-crystal X-ray diffraction analysis.
• The (Ph2PO)2BF2− ligand shows a stronger ligand-field strength than Ph2POMe.

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(Me2dtc)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)2BF2}] (1), where bis(diphenylphosphinito)difluoroborate was probably formed by hydrolysis of PClPh2 followed by reaction with BF4− 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(Me2dtc)2(Ph2POMe)2]BF4.

Bis(diphenylphosphinito)difluoroborate, (Ph2PO)2BF2−, was formed by hydrolysis of PClPh2 followed by reaction with BF4−, and isolated as the cobalt(III) N,N-dimethyldithiocarbamato complex.Figure optionsDownload as PowerPoint slide