Structural chemistry and optical application

Licentiate thesis, 2006

The demand for materials with optical activities against LASER radiation has been extensively increased over the last decade with the development of sophisticated high energetic LASER sources. The goal is to obtain organic or metal-organic molecules capable of increasing their absorptions against LASER irradiance while still maintaining a degree of transmittance. For instance, Zn-meso-tetrakis [bromothiophene] porphyrin is presented here as an efficient optical power limiter against Nd:YAG beam. Moreover, Schiff’s bases based on bromothiophenes show a degree of NLO performance against LASER. Single crystal X-ray crystallography has represented an active area of research leading to better understanding of many chemical and structural phenomena, thus the geometrical and electronic analogy for the fourth and the fifth bromine atoms position at the thiophene ring had been addressed. This thesis describes porphyrins, metalloporphyrins and conjugated thiophenes as optical limiters and non-linear optical materials with insight on the chemical and physico-chemical theories describing these actions. The organic molecules prepared in this work are meso-tetrakis 4-and 5-Bromo thiophene porphyrins, Bis thiophenyl 2-methylene hydrazine, Bis 4-bromothiophenyl 2-methylene hydrazine and Bis 5-bromothiophenyl 2-methylene hydrazine. The metal-organic molecules prepared in this work are Ag (II), Zn (II) meso-tetrakis 4- and 5-Bromo thiophene porphyrins as well as Zn (II) trans-bis nicotinato chloride. The syntheses, characterizations and optical properties as well as x-ray crystal structures of 2 metal-organic and 3 organic structures are presented and discussed.