David J. Ando

Bis(tetrathiofulvalenyl)sulphide [(TTF)2S] : synthesis and x-ray crystal structure

Abstract Bis(tetrathiafulvalenyl)sulphide [(TTF)2S] has been synthesized by reaction of monolithiated TTF with di(phenylsulphonyl)sulphide, and characterised by cyclic voltammetry and single crystal X-ray analysis, which reveals a remarkably close two-dimensional chalcogen network in the solid state. The synthesis of (TTF)2Se, using the selenating reagent di(phenylsulphonyl)diselenide, is also reported. Bis(tetrathiafulvalenyl)sulphide [(TTF)2S] has been synthesised by reaction of monolithiated TTF with di(phenylsulphonyl)sulphide, and characterised by cyclic voltammetry and single crystal X-ray analysis, which reveals a remarkably close two-dimensional chalcogen network in the solid state. The synthesis of (TTF)2Se, using the selenating reagent di(phenylsulphonyl)diselenide, is also reported.

Chiroptical spectroscopic studies of polydiacetylenes

Abstract A new class of optically pure, chiral, soluble polydiacetylenes have been synthesized. These show both solvato- and thermo-chromism, with behaviours similar to those reported for the well-studied analogous achiral m -butoxycarbonylmethylurethane ( m BCMU) class of polydiacetylenes. Although it is now generally agreed that this chromic behaviour is a direct result of the order-disorder transformation of the dissolved polymer, there still remains disagreement about the conformation and state of aggregation of the various forms. The chiral structure of these new polymers allows these general questions to be addressed through the use of circular dichroism spectroscopy. We report measurements obtained on both solution and thin film samples. These have allowed us to characterize more precisely the various states involved.

Spectroscopic studies of polydiacetylene solutions and glasses

Abstract Absorption, fluorescence excitation and emission spectra of a soluble polydiacetylene, obtained by the solid-state polymerization of the bis-(phenyl acetate) ester of 10,12-docosadiyne-1. 22-diol, have been recorded at room and liquid-nitrogen temperatures for different solvents. Spectral shifts, similar to those reported for other soluble polydiacetylenes, are observed on addition of a non-solvent or on cooling the solutions. The fluorescence quantum yield was measured from 2-methyl tetrahydrofuran solution at room temperature. The yield, was roughly one hundred times larger for this system at 77 K and well-structured fluorescence spectra were observed for this low-temperature glass.

Transition metal impurities in crystalline conjugated polymers

Abstract Two disubstituted diacetylene monomers and their corresponding polymers were found to contain transition metal impurities, the presence of which may be associated with the observation of anomalous e.s.r. absorption spectra. Copper complex impurities are considered responsible for the observed paramagnetism which is thought to arise from their inclusion at specific sites within the monomer crystal.

A remarkable rearrangement during reaction between triazolopyridinium ylides and dimethyl acetylenedicarboxylate

Abstract The ylides from 2-acylmethyltriazolopyridinium salts ( 1 ) react with dimethyl acetylenedicarboxylate in toluene solution to give the 7-pyrroleninylpyrazolo[1,5-a]pyridines ( 5 ).

Pyroelectric effect in crystals of the bis-toluene sulphonate diacetylene monomer and polymer

Abstract The pyroelectric properties of the monomer and partially and fuly polymerized crystals of the bis(p-toluene sulphonate) of 2,4-hexadiyne-1,6-diol (TS) were measured along their b axes from 100 to 300 K. Two peaks in the pyroelectric current of monomer crystals were found at 192 and 151 K. It is concluded that these crystals lack a centre of symmetry.

On the relationship of optical absorption energy and conversion during the polymerization of a crystalline diacetylene

Abstract Shifts in the optical absorption energy of polymer chains during polymerization of microcrystalline bis(p-toluene sulphonate) diacetylene are shown to be in accord with changes in the strain imposed on the chains by the mismatch of the monomer and polymer crystal lattices.

Crystal structure of poly[1,2-bis(p-methoxybenzenesulphonyloxymethyl)-1-buten-3-ynylene]

Abstract The crystal structure of poly[1,2-bis(p-methoxybenzene-sulphonyloxymethyl)-1-buten-3-ynylene] is presented. The structure is compared with that of the well-studied toluene sulphonate polymer. The similarities in the structures of the two polymers imply similarities in those of the monomers. Since the Raman spectra show similar lattice distortions during polymerization for both materials, it is concluded that the different polymerization kinetics indicate that lattice strain is not the dominant factor influencing the kinetics.

Fabrication And Characterisation Of Processable Polydiacetylene Waveguides

The synthesis of a new class of soluble polydiacetylenes is reported. Large area films of one of this class, 9-SMBU, have been formed by deposition from solution. The non-linearity of films of 9-SMBU has been measured by THG and demonstrates the trade-off between processability and non-linearity. The material was also deposited in channels etched in Si0xNy substrates and we have demonstrated, for the first time, channel optical waveguiding in a non-linear polydiacetylene material. Linear optical characterisation of these channels has been carried out at a laser wavelength of 1.3 μm. These waveguides should allow demonstrations of all-optical non-linear effects in guided wave devices.

Pyroelectric and Dielectric Behaviour of the Crystals of The Bis-Toluene Sulphonate Diacetylene Monomer and Polymer

Abstract The pyroelectric and dielectric properties of the monomer and partially and fully polymerized crystals of the bis(p-toluene sulphonate) of 2,4-hexadiyne-1,6-diol (TS) were measured along their b-axes from 100 – 300 K. The transition temperatures of the crystals determined from pyroelectric anomalies are similar to those from X-ray and heat capacity determination. The ageing effect of polymer TS crystals has been observed. It is concluded that these crystals lack a Centre of Symmetry.