Cyanide and nitrile compounds with applications in materials and cluster chemistry.

摘要

Novel transition metal cyanide and nitrile compounds are targeted as building blocks for the synthesis of clusters or materials that might exhibit interesting magnetic properties. The reaction of Mo₂Cl₄(dppm) ₂ with [n-Bu₄N][CN] produces [n -Bu₄N]₂[Mo₂(CN)₆(dppm) ₂] the first example of an edge-sharing bioctahedral compound of Mo(II) and only the third example of a structurally characterized metal-metal bonded compound with terminal cyanide ligands. Investigations of the electrochemistry of [Mo₂(CN)₆(dppm)₂]2− led to the isolation of the one and two electron oxidation products [Mo ₂(CN)₆(dppm)₂]− and Mo ₂(CN)₆(dppm)₂. A series of transition metal compounds were prepared with the facial capping ligand 1-(hydro)trispyrazolylborate and three acetonitrile or cyanide ligands. The facial arrangement of the dangling cyanides and acetonitrile leaving groups in these compounds were designed to allow for the formation of molecular cubes. Displacement of the acetonitrile leaving groups by nitrogens of the cyanides could result in closure and formation of heterobimetallic cubic clusters and reactions to this end were investigated. The aromatic molecule, hexazatriphenylene-hexacarbonitrile (HAT-(CN) ₆), with trigonally disposed chelating sites was explored as an alternative to cyanide as a linking group for paramagnetic transition metal ions. Convenient chemical reduction routes to [HAT-(CN)₆]− and [HAT-(CN)₆]2− have been demonstrated. The transition metals Co and Zn can be used as reducing agents, but in these cases complexation of the metal with the reduced HAT-(CN)₆ species occurs to yield the soluble paramagnetic complexes M[HAT-(CN)₆] ₂ (M = Co, Zn). Computational and EPR spectroscopic studies indicate [HAT-(CN)₆]2− has a triplet ground state electronic configuration.