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The reaction between iPr2 PCl and one equivalent of MeMgBr, followed by one equivalent of BH3·SMe2, gives the phosphine-borane iPr2 P(BH3)Me (4). Treatment of 4 with nBuLi, followed by Me3 SiCl, gives the sterically demanding phosphine-borane {iPr2 P(BH3)}(Me3 Si)CH2 (5) in good yield. Metalation of 5 with nBuLi yields {iPr2 P(BH3)}(Me3 Si)CHLi (6), which was crystallised as the TMEDA adduct [{iPr2 P(BH3)}(Me3 Si)CH]Li(TMEDA) (6a) and characterised by X-ray crystallography [TMEDA = N,N,N′,N′-tetramethylethylenediamine]. The reaction between two equivalents of in situ-generated 6 and Cp2 Sn in toluene gives the dialkylstannylene [{iPr2 P(BH3)}(Me3 Si)CH]2 Sn (7), which was crystallised from methylcyclohexane/THF as the rac diastereomer. X-ray crystallography reveals that stabilisation of the Sn centre in 7 is afforded by two agostic-type B-H…Sn interactions, one from each BH3 group.

The reaction between either Mg[I.sub.2] or Ca[I.sub.2] and equiv of [[(M[e.sub.3]Si).sub.2]]{M[e.sub.2]([H.sub.3]B)P}C]K in toluene which gives the corresponding organo-alkaline earth metal compounds [[(M[e.sub.3]Si).sub.2]]{M[e.sub.2]([H.sub.3]B)P}C]].sub.2] in moderate to good yields [M = Mg, Ca] is presented. The findings suggest that though heavier alkali metal complexes of the phosphine-borane-stabilized carbanion [[[(M[e.sub.3]Si).sub.2]]{M[e.sub.2]([H.sub.3]B)P}C].sup.-] are accessible, their stabilities, especially toward solvents are dependent upon the nature of the cation.

A comparative study of the carbonyl-ene reaction between a range of 1,1'-disubstituted or trisubstituted alkenes and ethyl trifluoropyruvate catalyzed by Lewis acid-platinum group metal complexes of the type [M{(R)-BINAP}].sub.2.plus (M= Pt, Pd, Ni; BINAP is 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), is presented. The palladium-based Lewis acid [Pd-{(R)-BINAP}].sup.2.plus is found to catalyze the ene reaction between methylene cycloalkane to afford the expected [alpha]-hydroxy ester in good yield and excellent diastereo- and enantioselectivity.

The anion-exchangeable framework hydroxide ([Yb.sub.3]O[(OH).sub.6]Cl.2[H.sub.2]O) is prepared hydrothermally. The framework is thermally stable below 200 [degree]C, it can be reversibly dehydrated and rehydrated with no loss of crystallinity and it undergoes anion-exchange reactions with small ions such as carbonate, oxalate and succinate with retention of the framework structure.

The combined use of the bimetallic aluminum(salen) complex [[Al(salen)].sub.2]O and tetrabutylammonium bromide (or tributylamine) has catalyzed the reaction between epoxides and carbon disulfide, which has produced 1,3-oxathiolane-2-thiones and 1,3-dithiolane-2-thiones as main products. The structure and stereochemistry of three of the 1,3-dithiolane-2-thiones is determined and is used to correct errors concerning the synthesis of cyclic di- and trithiocarbonates.

Tritylimidazoles have undergone sterically driven N -> N trityl migrations under thermal conditions. These migrations are the key steps in many highly diastereoselective domino reaction sequences (Diels-Alder, [1,3]-H shift, [1,3]-trityl migration and Diels-Alder, [1,3]-H shift, [1,3]-trityl migration, Michael reaction) that have led to architecturally complex molecules.

A series of compounds containing two boron dipyrromethene (Bodipy) units is prepared and characterized in which the spacer between the two Bodipy groups is varied from dibenzothiophene (BD1), to dibenzofuran (BD2), to 9,9-dimethylxanthene (BD3), and to diphenyl ether (BD4 and BD5). The optical intervalence charge-transfer (IVCT) band is attributed to electron exchange between the cofacially arranged neutral and mono-oxidized Bodipy units.

The studies of photoactive molecular dyads, BOD-T4, composed of a boron dipyrromethene (BODIPY) dye equipped with a tetrameric oligo-thiophene residue (T4) sited at the meso position are reported. The fluorescence-excitation spectrum recorded for emission from the BODIPY unit shed light on the fluorescence quenching due to intramolecular electronic energy transfer from T4 to BODIPY.

The first direct experimental evidence for the formation of bimetallic complexes containing two titanium ions with different salen ligands attached to each ion, or one titanium and one vanadium ion with either the same or a different ligand linked to each metal ion is presented. The structural results provide insights into the strong rate-inhibiting effect of vanadium(V)(salen) complexes in asymmetric cyanohydrin synthesis catalyzed by [[(salen)TiO].sub.2] complexes.