Synthesis, characterization and reactivity of coordination compounds of group 12 metals containing the N2-donor ligand bis(3,4,5-trimethylpyrazol-1-yl)methane

Article abstract of DOI:10.1016/0277-5387(94)00297-R

The interaction between bis(3,4,5-trimethylpyrazol-1-yl)methane, L(T), and several MX2 salts, gives 1:1 [L(T)]MX2 (M=Zn, Cd or Hg; X=Cl, Br or I; M=Zn, X=trifluoroacetate, M=Hg, X=CN, SCN or saccharinate) and 2:1 [L(T)]2MX2 adducts (M=Zn, X=NO3, ClO4, BF4, B(C6H5)4 or CF3SO3; M=Cd, X=NO3, ClO4 or BF4; M=Hg, X=ClO4) which are air- and thermally stable, while the reaction of L(T) with Hg(CF3COO)2 gives the basic salt [L(T)]Hg(CF3COO)2.5/4HgO. The adduct [L(T)]ZnCl2 readily reacted with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (Q'H), in the presence of a base, to yield the mixed-ligand complex [L(T)(Q')2Zn], whereas (Q')2Cd.[H2O] and (Q')2Hg.[Et2O] were obtained when a similar reaction was carried out with [L(T)]CdI2 and [L(T)]HgCl2, respectively, as starting materials. The compound [L(T)]ZnCl2 reacted with the anionic pyrazolato ligand (pz(-)) and with the neutral 1-methylimidazole (ImH') yielding the complexes (pz)2Zn and (ImH')2ZnCl2, respectively. Displacement of the ligand L(T) was observedalso from the reaction of [L(T)]CdBr2 with 4-phenylimidazole (ImH*) and from the reaction of [L(T)]ZnCl2 and [L(T)]ZnBr2 with 2,2'-bipyridyl (B ipy), while no interaction was observed with pyridine (py), pyrazole (pzH), 4-bromopyrazole (4-BrpzH) or 3,5-dimethylpyrazole (3,5-Me2pzH). All the compounds obtained were characterized from analytical and spectral data (IR, far-IR, (1)H and (13)C).