Metal polypyrazolylborates .13. Solution and solid state NMR study of cyano-mercury(II) polypyrazolylborates. X-ray crystal structure of [HB(3,5-Me(2)pz)(3)]HgCN

Complexes of the cyanomercury cation with various polypyrazolylborato ligands of the type HB(pz)(3) . Hg-CN or pzB(pz)(3) . Hg-CN (pz = pyrazolyl or substituted pyrazolyl) have been synthesised and characterised by IR, conductivity, H-1, C-13, and Hg-199 NMR spectroscopy. The crystal structure of the cyanomercury hydridotris(1H-3,5-dimethylpyrazol-I-yl)borate has been resolved (space group <P(1)over bar> with a = 7.863(3), b = 11.157(5), c = 13.117(5)Angstrom; alpha = 89.32(3), beta = 78.31(3), gamma = 79.13(4)degrees, V = 1106.22 Angstrom(3), Z = 2) showing a distorted tetrahedral coordination around Hg. The tris(pyrazolyl)borato complexes contain four-coordinated Hg and are rigid in solution at r.t., while the tetrakis(pyrazolyl)borates are fluxional. The N-15-CPMAS-NMR spectrum of the pzTp . HgCN derivative suggests a tetracoordination around mercury in this complex in the solid state. (C) 1997 Elsevier Science S.A.