Some ring expansions and related reactions of the phosphole system

The chemistry of simple phosphole derivatives is comprehensively reviewed to the early part of 1970. Using 1,2,5-triphenylphosphole and some of its derivatives as starting materials, several ring expansion and related reactions of the phosphole system have been i studied. Thus, pyrolysis and photolysis of 3,4,5- triphenyl-4-phosphabicyclo [3.1.0] hex-2-ene-4-oxide and certain pyrazolino derivatives of 1,2,5-triphenylphosphole oxide lead to the formation of compounds of formula (see document for formula). These compounds are shown to be derivatives of the 4,4’- diphosphabi (cyclohexa-1,5-dienyl) and 4,4'-diphosphabi- (cyclohexa-2,5-dienylidene) systems respectively and possible mechanisms for the formation of these compounds are discussed. Furthermore, the first of these compounds may be converted into the second in an unusual reaction in which lithium aluminium hydride acts as an oxidizing agent. The alkaline hydrolysis of 1-iodomethyl-l,2,5- triphenylphospholium iodide is discussed as a possible route to unsymmetrically substituted phosphorins

Thallium pi-cation complexation by calix[4]tubes: Tl-205 NMR and X-ray evidence

Thallium cation complexation by calix[4]tubes has been investigated by a combination of (TI)-T-205, H-1 NMR and ES MS demonstrating the solution formation of a dithallium complex in which the cations are held in the calix[4]arene cavities. In addition, the structure of the complex has been determined in the solid state revealing the cations to be held exclusively by pi-cation interactions. Furthermore, this crystal structure has been used as the basis for molecular dynamics simulations to confirm that binding of the smaller K+ cation in the calix[4]tube cryptand like array occurs via the axial route featuring a g-cation intermediate