| The work presented herein describes the implementation of a scheme to generate transition metal clusters in the gas phase, and isolate them in bulk through a process of ligand-passification. Additionally, several new tungsten clusters are synthesized via low-temperature solid-state routes. A wide array of these, and other clusters, are then examined with density functional theory (DFT).; Chapter 2 describes the implementation of a metal atom reactor designed to vaporize and passivate metal-nonmetal clusters from their parent binary solids. Through resistive heating of various transition metal chalcogenides under vacuum, and co-condensation with a matrix of trialkyl phosphine, Cr 6S8(PEt3)6, Co6S8(PEt 3)6, Fe4S4-(PnBu 3)4, Cu12S6(PEt3)8 , Cu26Se13(PEt3)14, and Cu70Se35(PEt3)21 were synthesized.; The resistive heating method described in Chapter 2 is insufficient for the vaporization of the more refractory metal carbides. Chapter 3 recounts an attempt to build a reactor that uses pulsed laser ablation to generate and passify metal clusters on a macroscopic scale.; Chapter 4 describes the initial access to the chemistry of hexanuclear tungsten oxohalide clusters, provided through the reduction of WOCl4 with bismuth metal at 360°C. Two D3 d-symmetric, edge-bridged isomers of [W6O6 Cl12]2- and at least one isomer of [W 6O7Cl11]3- are synthesized. Their electronic structures are probed by cyclic voltammetry, absorbance spectroscopy, and DFT.; In Chapter 5, I examine the electronic structure of [W6CCl 18]n- (n = 0, 1, 2, 3) using DFT. This carbon-centered, trigonal prismatic tungsten cluster displays interesting Jahn-Teller distortions in the 3-oxidation state, which is readily explained by population of one of a pair of e' orbitals. Vibrational spectra for the 1- and 2-oxidation states of the cluster, and the transition from the D3h-symmetry cluster to a possible D3d-symmetric isomer were also calculated.; Chapter 6 describes using DFT to find [M6Q8(CN) 6]n- (M = Re, Os, first-row transition metal; Q = S, Se; n = 0, 1, 2, 3, 4) clusters with frontier molecular orbitals of the proper symmetry and energy for strong magnetic coupling. The unpaired electrons of the cis and trans isomers of [Re4Os2Se8(CN)6]3- do indeed populate orbitals with electron density on the terminal cyanide ligands, allowing potential magnetic communication to other metals through the CN pi-bond. Chapter 6 ends with a survey of the relative stabilities of the octahedral, cyanide-terminated, first-row transition metal-sulfur clusters. |
