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A combined experimental and density functional theory (DFT) study of the reactions of the titanium imido methyl cation [[Ti([N.sup.1])Bu)([Me.sub.3][9]ane[N.sub.3])Me].sup.}[4.sup.} with Al[Me.sub.3] and Zn[Me.sub.2] is presented. These studies have helped in understanding the molecular and electronic structures and energetic aspects of Al[Me.sub.3] and Zn[Me.sub.2] adducts of group 4 monomethyl cations.

The diaminobist(phenoxide) supported rare-earth borohydride complexes [M(O2NN')(mu-BH4)(THF)n]2(I-M; H2O2NN' = (2-C5H4N)CH2N{2-HO-3,5-C6H2(super t)Bu2}, where M=Y(super III), n = 0.5; M = Sm(super III), n = 0; M = Nd(super III), n = 1] are reported along with certain chloride analogues and pyridine adducts. Compounds I-M initiate the ring-opening polymerization of the cyclic esters e-capolactone, L-lactide, and rac-(D,L)-lactide, hecrotectic enrichment upto 87%.

A study shows that the reaction of Ti(NMe2)2Cl2 with a wide range of primary alkyl and arylamines RNH2 gave the corresponding 5-coordinate imido titanium compounds Ti(NR)Cl2(NHMe2)2. The study also represents how supramolecular structure of imido compounds may be influenced by simple variation of the imido ligand N-substituent.

Research describes synthesis of hydrotris(3-isopropyl-4-bromopyrazolyl)borate (Tp') ligand starting from iron(II), manganese(II), and cromium(II). Results show that formation of MTp'(sub)2 octahedral complexes involves borotropic rearrangement of one pyrazolyl ring per ligand. X-ray structural analysis indicates that the metal centers exhibit distorted tetrahedral coordination.

Two new thiosemicarbazone-pyridlhydrazine (THYNIC) hybrid ligands are synthesized and copper(II), copper(I) complexes of the ligands are prepared and characterized by X-ray crystallography. Cyclic voltammetry measurements reveal that the copper(II) complexes undergo quasi-reversible reductions at biologically accessible potentials.

A preparation of the first templated TiGaPO with a 3-D framework structure is reported whereby TiGaPO-1 contains mixed-valence Ti(super III/IV) and has an octahedral-tetrahedral structure in which the Ti(super III), Ti(super IV), and Ga(super III) cation lie on distinct, identifiable sites. It is revealed that heating in air results in oxidation to a material containing Ti exclusively in the 4+ oxidation state with retention of the octahedral-tetrahedral framework structure.

An efficient and highly enantioselective catalytic intermolecular hydroacylation process is achieved by exchanging alkenes for allenes as substrates. 1,3-Disubstituted allenes and [beta]-S-aldehydes are used for developing the first efficient and highly enantioselective intermolecular carbon-carbon double-bond hydroacylation process.

The crystal structure of 1.2[Et.sub.2]O reveals the anionic units with an adamantine like [Al.sub.6][N.sub.4] skeleton. The main product of the reaction between [Prn[H.sub.3]]Cl and LiAl[H.sub.4] is neutral.

The synthetic, structural, and polymerization studies of new vanadium(4+) imido synthons of the type V(NR)Cl2(NHMe2)2 and their TACN (1,4,7-trimethyltriacyclononane) and TPM (tris(3,5-dimethylpyrazolyl)methane) derivatives are described. The differences in comparison with the highly active TACN- and TPM-supported titanium(4+) analogues are consistent with the results obtained for vanadocene, CGC (constrained geometry catalyst), and diamide-based vanadium(4+) catalyst systems.

The reaction of Ti(NMe(sub 2))(sub 2)Cl(sub 2) with 1,1-disubstituted hydrazines H(sub 2)NNR(sub 2) produces either monomeric terminal hydrazido (for R=Ph) or dimeric hydrazido-bridged species (for R=Me) or R(sub 2)=(CH(sub 2)(sub 5)). The monomeric compound Ti(NNPh(sub 2))Cl2[HNME(sub 2)](sub 2) and its bis(pyridine) homologue are precursors to a number of new terminal hydrazido titanium compounds.

The use of the imidazo-[1,5-a]pyridine skeleton for the synthesis of unprecedented carbenes D and the mesoinic structures E, containing single bridgehead nitrogen, and the first transition-metal complexes derived therefrom is reported. The imidazo[1,5-a]pyridine skeleton is a versatile platform for the synthesis of new types of free N-Heterocyclic carbenes (NHC's) and their transition-metal complexes.

A general anion templation procedure for assembling a wide range of pseudorotaxanes, which contain positively charged pyridinium, pyridinium nicotinamide, imidazolium, benzimidazolium and guanidinium threading components, and macro cyclic isophthalamide polyether ligands is developed. In noncompetitive solvent media, a halide anion of a potential cationic threading component continues to be coordinatively unsaturated.

LT-CuCN reacts easily at room temperature with a number of aqueous alkali-metal halide solutions to form a fascinating series of AX-CuCN addition products in which the -(CuCN)- chains present in CuCN itself are retained. It is shown that even simple looking systems can produce intriguing new materials with wide structural diversity.

The [2]- and [3] catenane structures to be synthesized using anion templation is described. The result indicates that anion binding by the pyridinium component is greatly influenced by catenation, leading to dramatic changes in anion selectivity trends.

Reaction of [Cu(MeCN)4](super +) with thiosemicarbazone bearing groups such as phenol, pyridine, or ferrocene gives tetranuclear or hexanuclear clusters with functional substituents. It is found that the silver compounds contains the same structural motif and it provide oxygen stable alternatives to the copper complexes which rapidly oxidize in the presence of oxygen to give copper(II) complexes.

Research has been conducted on silver-antimony sulfides. The authors report that these compounds have been prepared solvothermally in the presence of ethylenediamine, and have been characterized via thermogravimetry, elemental analysis and single-crystal X-ray diffraction.

This article describes the reaction of arylhydrazines with perrhenate in acetonitrile to form a mono aryl diazenide complex in high yields. The complex upon extensive high-yield substitution reactions lead to the synthesis of radiopharmaceuticals based on rhenium. The oxidation state rhenium complexes contain bifunctional ligands.