[Study on adductive reaction of Ni[(C4H9O)2PS2]2 with nitrogen base by spectrographic method].

Reactions of Ni[(C4H9O)2PS2]2 (NiL2) with Pyridine, 4-methylpyridine, 3,5-lutidine, 2,4-lutidine and 2,4,6-lutidine have been studied by spectrophotometry in ethanol at 32 degrees C. With B = 2,4-lutidine and 2,4,6-lutidine, the formation of NiL2.B2 only is concluded. For other nitrogen bases(B), the adduct formation of NiL2.B and NiL2.B2 is established, and their adductive equilibrium constants (lg beta n) and molecules (n) have been discussed. All the NiL2.B and NiL2.B2 complexes exhibit virtually the same electronic spectra arising from the five-coordinate NiNS4 and six-coordinate NiN2S4 chromophore respectively. The adductive equilibrium constants (lg beta n) increase with basicity (pKa) of nitrogen bases and can be described by experimental formulas: lg beta 1 = -0.186 + 0.352 pKa; lg beta 2 = 3.16 + 0.083 pKa.