Metal-doped polyoxotitanium cages (M-POTs) of the type [TixOy(OR)zMnXm] (M = a main group, transition metal or lanthanide; X = an anion such as a halide) can be regarded as molecular fragments of metal-doped TiO2. As such M-POTs can be used as structural models for the inclusion of metal ions into the TiO2 lattice and the ways in which well-defined microstructural changes affect photo-induced hole-electron separation. They are also potential organically-soluble redox-catalysts for a range of organic transformations and have been shown to be useful single-source precursors for the deposition of metal-doped TiO2. The applications of M-POTs as molecular precursors to metal-doped TiO2 offers a high degree of atomic control in the low temperature fabrication of photocatalytic thin films, which have applications in pollution control and water splitting. This perspective highlights the structural trends in M-POTs, their electronic behaviour and their applications as single-source precursors, looking at current and future trends in the development of inorganic precursors for device applications.

The NGFI-A gene encodes a "zinc-finger" protein that is rapidly induced by nerve growth factor (NGF) in PC12 rat pheochromocytoma cells. The complete exon/ intron organization and nucleotide sequence of the rat NGFI-A gene have been determined. The gene spans 3789 nucleotides (nt) and is interrupted by a single intron at nt 588. All three zinc-finger DNA-binding domains are contiguously coded for within the 3' exon; this is in contrast to the structure described by others for the Xenopus laevis transcription factor TFIA gene. To analyze the transcription of this gene, we have determined the transcription start site and nucleotide sequence of the 5' flanking region. Transfection of PC12 cells with a fragment from the 5' flanking region linked to the chloramphenicol acetyltransferase (CAT) gene revealed that it contains an element which imparts an NGF-inducible phenotype to the normally silent CAT gene. Several regions with homologies to recognizable sequence elements are present in this fragment, including a TATA box at nt -27, serum response elements at nt -84, -106, -370, and -408, a cAMP-responsive element at nt -140, and a transcription factor Spl-binding site at nt -286. These results establish the genomic structure of this mammalian multifinger protein and demonstrate that an NGFresponsive element lies upstream of the NGFI-A gene.

Experimental results have long suggested that catalyst optimization is an inherently multivariate process, requiring the screening of reaction conditions (temperature, pressure, solvents, precursors, etc.), catalyst structure (metal and ligands), and substrate scope. With a view to demonstrating the feasibility and utility of multivariate computational screening of organometallic catalysts, we have investigated the structural and electronic properties of a library of transition-metal-coordinated alkyne and vinylidene tautomers in different coordination environments. By varying the substituents on the organic moiety of 60 alkyne/vinylidene pairs we were able to capture and quantify the key structural and electronic effects on tautomer preference. For a carefully selected subset of substituents, the effects of metal and ancillary ligands were then explored. We have been able to formulate a protocol for assessing the stabilization of vinylidenes in transition-metal complexes, suggesting that the d 6 square-based-pyramidal metal fragment [RuCl 2 (PR 2 3 )(CCHR 1 )], combined with electron-withdrawing substituents R 1 and electron-rich groups R 2 , would provide the ideal conditions favoring the vinylidene form thermodynamically.

Cobalt-containing polyoxotitanates (TiCo) are excellent precursors for the simple and scalable preparation of Nocera-type CoOx water-oxidation electrocatalysts. The TiCo cages serve as a reservoir for cobalt ions in a titania matrix on fluoride-doped tin oxide electrodes, and form, in situ, the active CoOx catalyst for O2 evolution with high stability in phosphate buffer in pH neutral water.

The solvothermal reactions of Ti(OEt)(4) with LnCl(3) (Ln = La, Ce) produced new Ti(28) Ln cages, in which the Ln(3+) ions are coordinated within a metallocrown arrangement, which represents the highest nuclearity cages of this type (see figure).