On the interaction of acylpyrazolonates with zinc(II) acceptors: the role of ancillary ligands

From the interaction of 1-phenyl-3-methyl-4-R-C(=O)-pyrazol-5-one (HQ(T): R=CH2C(CH3)(3); HQ(C): R=C6H11) with Zn(O2CCH3)(2). 2H(2)O in MeOH, derivatives [Zn(Q(T))(2)(H2O)] (1), [Zn(Q(T))(2)(MeOH)(2)] (2) and [Zn(Q(C))(2)(MeOH)(2)] (3) have been obtained. Heating 1 under Vacuum afforded the anhydrous [Zn(Q(T))(2)] (4). Compounds 1 and 3 react with N-2-donor ligands 1,10-phenanthroline (phen) and 2,2'-bipiridyl (bipy) in chloroform yielding [Zn(Q(T))(2)(phen)] (5), [Zn(Q(C))(2)(phen)] (6), [Zn(Q(T))(2)(bipy)] (7) and [Zn(Q(C))(2)(bipy)] (8), respectively. The adducts [Zn(Q(T))(2)(trime)] (9) and [Zn(Q(T))(2)(tmeda)] (10), respectively, were synthesised by carrying out the reaction between HQ(T) and Zn(O2CCH3)(2). 2H(2)O in the presence of N,N,N'-trimethylethylenediamine (trime) or N,N,N',N'-tetrainethylethylenediamine (tmeda). In the X-ray crystal structure of 9 the zinc was found six-coordinate in a slightly distorted octahedral environment, due to steric requirements of acylpyrazolonato and diamine donors. Finally, 2 interacts in Et2O with imidazole (im), 1-methylimidazole (1-Meim), diethylamine (Et2NH) and 1-methylimidazoline-2-thione (Hmimt) affording [Zn(Q(T))(2),(imH)(2)] (11), [Zn(Q(T))(2)(N-Meim)(2)] (12), [Zn(Q(T))(2)(Et2NH)(2)] (13) and [Zn(Q(T))(2)(Hmimt)](2) (14), respectively. ALI compounds 1-14 have been characterised both in the solid and solution states with analytical and spectral data. (C) 2000 Elsevier Science S.A. All rights reserved.