Synthesis, Structure And Property Of Organometallic Compounds Bearing Pyrazolato Ligand And 1, 2, 4-Diazaphospholide Ligands

Fourteen novel organometallic complexes were prepared with five-membered heterocyclic pyrazolato or 1,2,4-diazaphospholide as ligands and various metal ions including GaⅢ, FeⅢ, FeⅡ and CrⅢ. Some of them were structurally characterized by single crystal X-ray diffraction. The compounds with magnetic property were characterized by EPR analysis and magnetic susceptibility studies. The compounds were characterized by NMR and IR. The work was briefly desrcribed as following:1. Dinuclear pyrazolato gallium dichloride [(η1,η1-3,5-tBu2pz)GaCl2]2 (1) was prepared by [tBu2pz]K and GaCl3; Further reaction of 1 and dry silyl acetylenes gave bulky N-alkenyl substituted pyrazolato gallium dichloride 2-5. Reduction of 2 with alkali metal alloy gave a gallium (II) species (6) with Ga-Ga bond;2. The oxidation of 1,2,4-diazaphospholide potassium (7-) with FeCl3 or CuCl2 produced a neutral 1,2,4-diazaphospholyl radical (7·) which was evidenced by EPR as a spin adduct DMPO[7’]. Radical 7· is liable to self-associate toward a 7(N)-7(P) dimer through N-P coupling without DMPO. The DFT calculation suggested that 7(N)-7(P) formation is upon the thermodynamic stability of the intermediate 7·(N1)-7’(P2) and the electronic-spin structure combined with stereo electronic effects of 7·.3.The reaction of [3,5-tBu2dp]- (7-)or{[3,5-Ph2dp]-(0.67THF)}(8-) and CrCl3(THF)3 in a ratio of 1:1 gave organochromium compounds [(η2-3,5-tBu2dp)Cr(THF)2Cl2] (9) or [(η2-3,5-Ph2dp)Cr(THF)2Cl2] (10) respectively. Compound 9 was characterized by EPR analysis and magnetic susceptibility studies. The reduction of 9 and 10 with C8K gave two Cr(Ⅱ) species [(η1-3,5-tBu2dp)Cr(η2-3,5-tBu2dp)]2 (11) and (η1-3,5-Ph2dp)4Cr[(η53,5-Ph2dp)2K(THF)2]2 (12).4. The compound [(η1-3,5-Ph2Hdp)2(η1-3,5-Ph2dp)2Fe]2 (13) was prepared with{[3,5-Ph2dp] (0.67THF)} (8-), [3,5-Ph2Hdp] (8) and dry FeCl2/FeCl3 in a ratio of 2:2:1/3:3:1. The reaction of [2,6-bis(1,2,4-diazaphospholyl-1-yl)pyridine] and dry FeCl2/FeCl3 in a molar ratio of 1:1 gave a novel compound {[2,6-di(1,2,4-diazaphosphol-1-yl)pyridine]2FeCl4} (14).