Syntheses, crystal structures, optical limiting properties, and DFT calculations of three thiophene-2-aldazine Schiff base derivatives

Journal article, 2007

The syntheses, characterizations and structural determinations of N,N'-bis(thiophenyl-2- methylene)hydrazine 1, N,N'-bis(4-bromothiophenyl-2-methylene)hydrazine 2 and N,N'- bis(5-bromothiophenyl-2-methylene)hydrazine 3 are presented. The materials show third-order nonlinear behaviour with transmissions of 20, 22 and 18 μJ for an input energy of 150 μJ. The 4- and 5-bromothiophenic structures show Br...Br interactions of 3.562 and 3.626 Å, respectively. Analysis of bromine containing aromatic compounds in the Cambridge Crystallographic Database (CSD) showed the expected angle dependences of the Br...Br interactions dividing these into ‘‘type I’’ and ‘‘type II’’. A semi-quantitative agreement was found between the CSD data and a model derived form calculated electrostatic potentials.