Preparation of new monoanionic "scorpionate" ligands:: Synthesis and structural characterization of titanium(IV) complexes bearing this class of ligand

The preparation of new "scorpionate" ligands in the form of the lithium derivatives [{Li(bdmpzdta)(H2O)}4] (1) [bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], [Li(bdphpza)(H2O)(THF)] (2) [bdphpza = bis(3,5-diphenylpyrazol-1-yl)acetate], and [Li(bdphpzdta)(H2O)(THF)] (3) [bdphpzdta = bis(3,5-diphenylpyrazol-1-yl)dithioacetate] has been carried out. Furthermore, a series of titanium complexes has been prepared by reaction of TiCl4(THF)(2) with the lithium reagents [{Li(bdmpza)(H2O)}(4)] (4) [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] and 1. Under the appropriate experimental conditions neutral complexes, namely [TiCl3(kappa(3)-bdmpza)] (5), [TiCl3(kappa(3)-bdmpzdta)] (6), and [TiCl2(kappa(2)-bdmpzdta)(2)] (7), and cationic complexes, namely [TiCl2(THF)(kappa(3)-bdmpza)]Cl (8) and [TiCl2(THF)-(kappa(3)-bdmpzdta)]Cl (9), were isolated. Complexes 8 and 9 undergo an interesting nucleophilic THF ring-opening reaction to give the corresponding alkoxide-containing species [TiCl2(kappa(3)-bdmpza){O(CH2)(4)Cl}] (10) and [TiCl2-(kappa(3)-bdmpzdta){O(CH2)(4)CI}] (11). A family of alkoxide-containing complexes of general formulas [TiCl2(kappa(3) -bdmpza)-(OR)] [R = Me (12); R = Et (14); R = Pr-i (16); R = Bu-t (18)] and [TiCl2(kappa(3)-bdmpzdta)(OR)] [R = Me (13); R = Et (15); R iPr (17)] was also prepared. The structures of these complexes have been determined by spectroscopic methods, and in addition, the X-ray crystal structures of 3, 7, 10, and 11 were also established.