Study on thermal stability of poled non-linear optical polymers

A logarithmic expression is proposed to describe relaxation of the polar order in side chain polymers,together with a new way of plotting temperature dependent relaxation data.This results in a straight line extending even below the glass transition temperature in the case of poled nonlinear optics (NLO) side chain polymers.A simple procedure to determine the rotational diffusion constant Dr is given and Dr values of several polymer systems have been evaluated and compared with each other.It appears that,starting from the conventional and well known poled polymer system currently applied,a further lowering of Dr by about 3 orders of magnitude is necessary in order to reach an acceptable orientational stability or lifetime of poled polymers for practical applications.Attempts have been made to introduce electron push-pull substituents into high thermostable molecular frameworks and results of preliminary measurements are reported.     

The structure and magnetic properties of μ_3-oxotriiron(Ⅲ) complex [Fe_3O(OBz)_6(CH_3OH)_3](NO_3)(CH_3OH)_2

A new μ3-O triiron(Ⅲ) complex [Fe_3O(OBz)_6(CH_3OH)_3](NO_3)(CH_3OH)_2 (HOBZ = benzoic acid) has been synthesized, its structure has been determined and variable temperature magnetic susceptility has also been measured. In the molecule, three iron atoms formed an equilateral triangle with u_3-O in center. The fitting to the magnetic susceptibility showed that an intramolecular antiferromagnetic exchange interaction occurred between iron atoms with J=-25.51 cm~(-1), and a weaker intermolecular antiferromagnetic exchange interaction occurred with zJ' = -2.30cm~(-1).     

Synthesis and characterization of tris(η~5-cyclopentadienyl-μ-carbonyliron)-μ_3-nitrosyl cluster:X-ray structure of[(η~5-C_5H_5)(μ-CO)Fe]_3(μ3-NO).C_4H_8O

Tris)(η 5-cyclopentadienyl-μ-carbonyl-iron)-μ3-nitrosyl cluster was obtained from the reaction of cyclopentadienyl dicarbonyliron dimer with nitrogen monoxide in xylene. The cluster was characterized by elemental analyses, IR, MS and 1H NMR. The crystal structure of [(η5-C5H5)(μ-CO)Fe]3(μ3-NO).C4H8O was determined by X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pnma, a=9.053(2), 6=10.545(2), c=22.525(4) A, V=2150.3(7) A3, Z=4,Dc=1.68 g.cm-3; structure solution and refinement based on 1141 reflections with I > 3.0 (I) (MoKa, A=0.71073 A) converged at R=0.0540. The infrared absorption band at 1325 cm-1 of the μ3-NO in the cluster, which is red shifted, shows that μ3-NO is activated.