Inorganic Chemistry, Vol.53, No.23, 12449-12458, 2014
Synthesis and Structural Characterization of Group 4 Metal Carboxylates for Nanowire Production
The synthesis and characterization of a series of group 4 carboxylate derivatives ([M(ORc)(4)] where M = Ti, Zr, Hf) was undertaken for potential utility as precursors to ceramic nanowires. The attempted syntheses of the [M(ORc())4] precursors were undertaken from the reaction of [M(OBut)(4)] with a select set of carboxylic acids (H-ORc where ORc = OPc (O2CCH(CH3)(2)), OBc (O2CC(CH3)(3)), ONc (O2CCH2C(CH3)(3))). The products were identified by single-crystal X-ray diffraction studies as [Ti(eta(2)-OBc)(3)(OBut] (1), [Zr-2(mu(3)-O)(mu-OPc)(4)(mu,eta(2)-OPc)eta(2)-OPc)](2) (2), [H](2)[Zr eta(2)-OBc)(2)(OBc)(2)(OBc)(2)] (3), [Zr(mu-ONc)(2)eta(2)-ONc)(2)](2) (4), or [Hf(mu-ORc)(2)eta(2)-ORc)(2)](2) [ORc = OPc (5), OBc (6, shown), ONc (7)]. The majority of compounds (4-7) were isolated as dinuclear species with a dodecahedral-like (CN-8) bonding mode around the metals due to chelation and bridging of the ORc ligand. The two monomers (1 and 3) were found to adopt a capped trigonal prismatic and CN-8 geometry, respectively, due to chelating ORc and terminal ORc or OBu(t) ligands. The metals of the oxo-species 2 were isolated in octahedral and CN-8 arrangements. These compounds were then processed by electrospinning methods (applied voltage 10 kV, flow rate 30-60 mu L/min, electric field 0.5 kV/cm), and wire-like morphologies were isolated using compounds 4, 6 (shown), and 7.