Neutron diffraction studies of transition metal hydrides

Hydrogen is normally bonded to one atom and occasionally to two (hydrogen bonds). Transition metal hydrido complexes are unusual because in those molecules hydrogen can sometimes be coordinated to three or more atoms simultaneously, a bonding type that is unknown in organic or biological chemistry. Thus, these molecules are good models for studying hydrogen interaction with metallic systems.; Single-crystal neutron diffraction is the most powerful tool for the analysis of the structures of transition metal hydrido complexes. The neutron sources at the Argonne National Laboratory near Chicago and the Institut Laue-Langevin in France were both used for the neutron experiments described in this dissertation. In addition to those neutron structure determinations, we have also included in this thesis the x-ray diffraction analysis of two rhenium and tungsten polyhydride complexes, and the attempted solubilization of solid-state binary and ternary metal hydride complexes.; Four neutron diffraction studies of transition metal hydride complexes are described in Chapter 1–4. The compounds studied include: (i) a mononuclear dihydrido carbonyl iron complex, FeH₂(CO)₂[P(OPh) ₃]₂ (ii) a titanium/borohydride complex, Cp₂Ti{lcub}(μ-H) ₂BC₈H₁₄{rcub} (iii) a niobium complex with suspected agostic M-H-Si interactions, NbCp₂(SiMe₂Cl)(H)(SiMe ₂H) and (iv) a metal cluster containing face-bridging hydrogen atoms, [(η5-Me₄EtCp)CoH{rcub}₄].; Chapter 5 describes the syntheses and x-ray diffraction studies of two crowded polyhydride/phosphine complexes, ReH₇(PPh₃)2·C ₄H₈O and WH₄(PMePh₂)₄; while Chapter 6 describes attempts to solubilize ternary metal hydrides of the type A_xMH_y with crown ethers and cryptates, and the x-ray structural analyses of two of the resulting crystalline products.