Small Molecule Chemistry of the Pyrazolylborate-Zinc Unit Tp(Cum,Me)Zn.
The synthesis of the highly encapsulating pyrazolylborate ligand hydrotris(3-p-cumenyl-5-methylpyrazolyl)borate (L = Tp(Cum,Me)) and of its zinc hydroxide complex L.Zn-OH (1) are described. 1 is converted by H(2)S into the hydrosulfide complex L.Zn-SH (2). Both 1 and 2 seem to be contaminated with traces of the isomeric species 1' and 2' containing L' with one 3-methyl-5-p-cumenyl substituent. Thermal condensations of 1' and 2 yield the molecular zinc oxide and sulfide complexes L'.Zn-O-Zn.L' (3') and L.Zn-S-Zn.L (4). The hydroxide complex 1 has been found to react readily with cumulated double-bonded species: CO(2) is incorporated in alcoholic solutions to form the alkylcarbonate complexes L.Zn-OCOOR (5). Similarly, CS(2) in ethanol forms the O-ethyl dithiocarbonate complex L.Zn-SC(S)OEt (6). SO(2) is converted to a bridging sulfito ligand in L.Zn-O-SO-O-Zn.L (7), and phenyl isothiocyanate is bound as a thiocarbamidato ligand in L.Zn-SC(O)NHPh (8). Complexes 1, 2, 2', 3', 4, 5, and 6 have been confirmed by structure determinations and complexes 7 and 8 by spectral data.
Ruf
Michael
M
Institut für Anorganische und Analytische Chemie der Universität Freiburg, Albertstrasse 21, D-79104 Freiburg, Germany.
Vahrenkamp
Heinrich
H