Christopher M. Kepert

The reaction of iron carboxylates with titanium alkoxides. Isolation and structural characterisation of [Ti6(μ3-O)6(O2CPh)6(OCH2C(CH3)3)6]

Abstract The reaction of [Fe4(μ3-O)2(O2CPh)8(py)2] (1) with Ti(OPrn)4 in toluene yields separate Fe and Ti species each containing both carboxylate and alkoxide groups rather than a bimetallic FeTi complex. The addition of neopentanol to the reaction mixture has enabled [Ti6(μ3-O)6(O2CPh)6(OCH2C(CH3)3)6] (3) to be isolated and structurally identified. The compound [Ti6(μ3-O)4(O2CPh)8(OPrn)8] (4) has also been characterised and shown not to convert to a {Ti6(μ3-O)6}12+ core compound under the same temperature conditions used in the FeTi reactions.

Synthesis and structures of di(2-pyridyl)amine diruthenium(I) complexes, including an example of monodentate coordination

Addition of di(2-pyridyl)amine (dpa) to a solution formed by reaction of [Ru(CO) 2 Cl 2 ] n with NaOAc resulted in the precipitation of [Ru(OAc)(CO) 2 (dpa)] 2 , a complex containing a rare example of monodentate dpa coordination. X-ray crystallography revealed a dinuclear complex with a Ru–Ru bond, having two cis -carbonyls on each ruthenium trans to oxygen donors of two μ-acetate ligands and a monodentate dpa approximately colinear with the Ru–Ru bond. A variable temperature 1 H NMR study of this complex indicated fluxional behaviour of the dpa ligand in solution at room temperature, with the spectrum at 243 K corresponding to that predicted from the solid state structure. Heating of [Ru(OAc)(CO) 2 (dpa)] 2 in ethanol formed [Ru 2 (OAc)(CO) 4 (dpa) 2 ] + , which was isolated as the acetate salt. The X-ray structure of this complex and the analogous benzoate bridged [Ru 2 (PhCO 2 )(CO) 4 (dpa)]Cl confirmed the presence of a diruthenium(I) core with terminal chelating dpa ligands and bridged by one carboxylate and two carbonyl ligands.

Synthesis, molecular structure and magnetic properties of [Fe6(μ3-O)2(OPri)2(μ-OPri)6(O2CPh)2(μ-O2CPh)4]

Abstract The reaction of an Fe(III) oxo-benzoate species (1) with Al(OR)3 (R=Pri, Busec) yields the hexanuclear derivatives [Fe6(μ3-O)2(OR)8(O2CPh)6] (R=Pri (2); R=Busec (3)) which consist of planar Fe4(μ3-O)2 units, formed by two Fe3(μ3-O) groupings having common Fe(III) atoms, with further Fe(OR)4 entities, each attached by three bridging OR groups to Fe3(μ3-O) units, above and below the Fe4 plane. The OPri complex has an S=3 magnetic ground state and shows unusual temperature dependence of μeff below 60 K because of the complex series of low lying spin states generated by six high-spin Fe(III) centres undergoing antiferro- and ferromagnetic intracluster coupling. The Mossbauer spectrum at 81 K supports the presence of three inequivalent Fe sites in the molecule, as noted in the crystal structure.

Qualitative test for supramolecular complexation of C60using a mesoporous silica

A new form of mesoporous silica with a surface area of 600 m 2 g - 1 , mean pore radius of 5.4 nm and total pore volume of 1.9 ml g - 1 uptakes C 60 in toluene; on removal of toluene or the addition of fullerene complexing agents the C 60 undergoes aggregation within the silica, identified by an inter-fullerene resonant transition at ca. 450 nm.