Conformational analysis of some pyridinium phenolates and synthetic precursors based on X-Ray and IR characterisations

Abstract This manuscript reports X-ray and IR characterizations of representative pyridinium phenolates, model compounds for nonlinear optics. These analyses reveal the close dependence existing between molecular structure and the contribution of quinone and zwitterionic limiting forms. The bond length alternation (BLA) values, the well-known parameter correlated to hyperpolarisability β , are also discussed and compared with literature data.