Azido- and phosphiniminato-complexes of titanium and vanadium

Summary The azido complexes [Ti( ⁵-C₅H₅Cl₂(N₃)], [Ti( ⁵-C₅H₅)₂Cl(N₃)], [TiCl(N₃)(S₂CNEt₂)₂] and [Ti(N₃)(S₂CNEt₂)₃] have been prepared from appropriate metal halides by reaction with trimethylsilylazide. The [Ti( ⁵-C₅H₅)Cl₂(N₃)] complex reacts with HC1 and MeCOCl to give HN₃ and MeNCO respectively and [Ti( ⁵-C₅H₅)Cl₃], whereas [Ti( ⁵-C₅H₅)Cl₂(NPPh₃)] is formed on reaction with PPh₃. The phosphiniminato complexes [TiCl(NPPh₃)(S₂CNEt₂)₂], [TiCl₂(NPPh₃)₂], [VOCl₂(NPPh₃)], [VOCl(NPPh₃)₂] and [VCl₃(NPPh₃)₂] have been prepared from the appropriate halido-complexes and Me₃SiN=PPh₃.     

An unusual dimeric structure of a Cu(I) bis(thiosemicarbazone) complex: implications for the mechanism of hypoxic selectivity of the Cu(II) derivatives

The electrochemical reduction of Cu(II) bis(thiosemicarbazone) complexes [Cu(II)(btsc)] is accompanied by protonation to give an unstable Cu(I) intermediate [Cu(btscH(2))](+). The nature of this intermediate was probed by reaction of bis(thiosemicarbazone) ligands with a Cu(I) precursor which gave a novel helical dimeric dicationic complex. The dependence of these reactions on the ligand backbone substituents is discussed together with their possible relevance to the use of Cu(II) bis(thiosemicarbazone) ligands as hypoxic selective imaging and therapeutic agents.     

A convenient synthesis of 1, 1′-dithiolatoferrocene and the preparation of [ReO{Fe(C5H4S)2}2]−

Summary LiAlH₄ reduction of 1, 1-ferrocene-bis(dimethyldithiocarbamates) gives 1, 1-dithiolatoferrocene [Fc(SH)₂] in high yield. The dithiol reacts with first-row transition metals to give polymeric products but with [ReOCl₃–(PPh₃)₂] the complex [ReO(FcS₂)₂]^–, can be isolated as a tetraphenylphosphonium salt in good yield.     

A mono-diazenide complex from perrhenate: toward a new core for rhenium radiopharmaceuticals

A new method for the synthesis of low to intermediate oxidation state rhenium complexes containing a bifunctional ligand has been developed. Reaction of [ReO(4)](-) with substituted phenylhydrazines and triphenylphosphine in acetonitrile in the presence of HCl allows the isolation of [ReCl(2)(NNC(6)H(4)-4-R)(NCCH(3))(PPh(3))(2)] (where R = OCH(3), Cl, or CO(2)CH(3)). The substituted hydrazine acts as both a reductant and source of a monodentate diazenide ligand. The compounds have all been characterized in the solid state by X-ray crystallography and in the solution state by NMR, electrospray mass spectrometry, and HPLC. Cyclic voltammetry measurements show that the mono-diazenide complexes undergo a reversible oxidation.     

Organic azo complexes of molybdenum and their reactions with electrophiles

Organic azo(1) and N,N-disubstituted hydrazido-N'(2) complexes of molybdenum have been prepared by the reactions of certain molybdenum-oxo complexes with hydrazines.     

Synthesis, structure and catalytic activity of thioether-phosphane complexes of Pd(II) and Pt(II)

New thioether-phosphanes 2-RSC6H4CH2PPh2(RS-PPh2: R = Me, tBu, Ph) and the corresponding complexes [PdCl2(MeS-PPh2)], [PdCl2(tBuS-PPh2)], [PdCl2(PhS-PPh2)], [PdClMe(MeS-PPh2)] and [PtMe2(MeS-PPh2)] have been prepared, characterized and the X-ray crystal structures of all complexes determined. Whilst Pd(II) complexes of RS-PPh2 show low activity for CO/ethene copolymerisation, the complexes [PdCl2(RS-PPh2)] have been found to be very efficient for the Heck arylation of n-butylacrylate with bromobenzene under aerobic conditions.     

Pyridylthiocarbazide complexes of rhenium with potential radiopharmaceutical applications

Attachment of a thioamide tethering group provides a modification of the well-known pyridylhydrazine based route to radiolabelling of biomolecules (the HYNIC system) and gives a proligand which gives stable, well-defined chelated derivatives with both Re(v) oxo and Re(III) diazenide cores. Both display previously unknown bonding modes for the pyridylthiocarbazide ligands.     

An extension of Elton's theorem to complex Banach spaces

Let 0$"> be sufficiently small. Then, for , there exists such that if are vectors in the unit ball of a complex Banach space which satisfy

(where are independent complex Steinhaus random variables), then there exists a set , with , such that

for all (). The dependence on of the threshold proportion is sharp.