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 (HQT: R=CH2C(CH3)3; HQC: R=C6H11) with Zn(O2CCH3)2·2H2O in MeOH, derivatives [Zn(QT)2(H2O)] (1), [Zn(QT)2(MeOH)2] (2) and [Zn(QC)2(MeOH)2] (3) have been obtained. Heating 1 under vacuum afforded the anhydrous [Zn(QT)2] (4). Compounds 1 and 3 react with N2-donor ligands 1,10-phenanthroline (phen) and 2,2′-bipiridyl (bipy) in chloroform yielding [Zn(QT)2(phen)] (5), [Zn(QC)2(phen)] (6), [Zn(QT)2(bipy)] (7) and [Zn(QC)2(bipy)] (8), respectively. The adducts [Zn(QT)2(trime)] (9) and [Zn(QT)2(tmeda)] (10), respectively, were synthesised by carrying out the reaction between HQT and Zn(O2CCH3)2·2H2O in the presence of N,N,N′-trimethylethylenediamine (trime) or N,N,N′,N′-tetramethylethylenediamine (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(QT)2(imH)2] (11), [Zn(QT)2(N-Meim)2] (12), [Zn(QT)2(Et2NH)2] (13) and [Zn(QT)2(Hmimt)]2 (14), respectively. All compounds 1–14 have been characterised both in the solid and solution states with analytical and spectral data.