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)(H(2)O))(4)] (1) bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], Li(bdphpza)(H(2)O)(THF)] (2) bdphpza = bis(3,5-diphenylpyrazol-1-yl)acetate], and Li(bdphpzdta)(H(2)O)(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 TiCl(4)(THF)(2) with the lithium reagents (Li(bdmpza)(H(2)O))(4)] (4) bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] and 1. Under the appropriate experimental conditions neutral complexes, namely TiCl(3)(kappa(3)-bdmpza)] (5), TiCl(3)(kappa(3)-bdmpzdta)] (6), and TiCl(2)(kappa(2)-bdmpzdta)(2)] (7), and cationic complexes, namely TiCl(2)(THF)(kappa(3)-bdmpza)]Cl (8) and TiCl(2)(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 TiCl(2)(kappa(3)-bdmpza)(O(CH(2))(4)Cl)] (10) and TiCl(2)(kappa(3)-bdmpzdta)(O(CH(2))(4)Cl)] (11). A family of alkoxide-containing complexes of general formulas TiCl(2)(kappa(3)-bdmpza)(OR)] R = Me (12); R = Et (14); R = (i)Pr (16); R = (t)Bu (18)] and TiCl(2)(kappa(3)-bdmpzdta)(OR)] R = Me (13); R = Et (15); R = (i)Pr (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.