Solvatochromism, hyperpolarizability, molecular and crystal structure of betaine dye 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate

Abstract

Solvatochromic effect of 4-(2,4,6-triphenylpyridinium-1-yl)-phenolate hydrate, 1, was determined. CT absorption band, which gave the shift from 23,880 (in water solution) to 14,440 cm −1 (in anisole solution) allowed the molecular second order polarizability β CT to be estimated as 59.5×10 −30 cm 5 esu −1. The crystal structure of 1 was determined: C 29H 21NO·5.78H 2O; orthorhombic, C222 1, a=15.005(9), b=24.356(4), c=7.5097(9) Å; V=2744.5(17) Å 3, Z=4, D X =1.224 g cm −1; λ=0.71073 Å (Mo Kα); μ=0.087 mm −1; final R 1=0.0551 for 2882 reflections [ I>2 σ( I)]. The molecules of 1, in an anti-parallel arrangement, form columns along the c-axis through stacking between the pyridinium ring and a phenyl ring in para position of the neighbouring molecule. Water molecules filling channels between the columns are disordered. Two of water molecules are connected by hydrogen bonds with negatively charged oxygen atom of 1. Powdered samples of 1 revealed only weak SHG response as measured using HRS method in relation to urea standard.