Lavoie, Gino G.2015-12-162015-12-162015-08-102015-12-16http://hdl.handle.net/10315/30711I have completed work in the Lavoie Group which has resulted in the synthesis of new square pyramidal complexes supported by the tert-butyl-substituted (ethenediylidene)tetraphenoxide “TPO” ligand system. Complexes 6, 2,2',2",2"'-(1,2-ethenediylidene)tetrakis[4-tert-butylphenoxo] tantalum(V) ethoxide and 7, 2,2',2",2"'-(1,2-ethenediylidene)tetrakis[4-tert-butylphenoxo] tantalum(V) dimethylamide were synthesized and structurally characterized. Crystal structures confirmed that the geometry of complexes 6 and 7 is square pyramidal with the TPO ligand coordinating to tantalum slightly below the xy plane on which the metal resides. In addition, the ethoxo and dimethylamido ligands coordinate to tantalum on the z axis. Analyzing the X-ray structures gives valuable insight into pi-interactions between the metal center and the apical ligands. Bond lengths and angles from the structures indicate significant double bond character between the metal and the apical ligand. Reaction of (TPO)Ta(OEt) (6) and (TPO)Ta(NMe2) (7) with trimethylaluminum gave the methyl complex (TPO)Ta(CH3) (8). Bonding on complex 7 was further explored using density functional theory calculations.enAuthor owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Inorganic chemistryElectronic Thesis or Dissertation2015-12-16Tantalumsquare pyramidalcomplexespi-interactions5-coordinateinorganicnitrogen-tantalumtantalum-oxygenreactivitiesDFTcomputationmultiple-bondingdouble-bondsmethylationgroup 5metalssigma-interationsprotonolysisinsertionamidoethoxidemethylchlorogroup 6transition metalsnitrogensmall moleculespolymerization.