Spectroscopic and nonlinear optical properties of the four positional isomers of 4α-(4-tert-butylphenoxy)phthalocyanineElectronic supplementary information (ESI) available: Calculated electronic absorption spectra. See DOI: 10.1039/c5tc01601k

The spectroscopic and nonlinear optical properties of the positional isomers of metal free 4α-(4- tert -butylphenoxy) phthalocyanine are presented. Second order nonlinear polarizability ( β ), imaginary hyperpolarizability (Im( γ )) and imaginary susceptibility (Im[ χ (3) ]) values were determined for the four positional isomers. The measured β values of the four isomers displayed the following trend, C 4h (34.0 × 10 −5 m MW −1 ) > D 2h (28.8 × 10 −5 m MW −1 ) > C 2v (22.8 × 10 −5 m MW −1 ) > C s (13.7 × 10 −5 m MW −1 ). An enhanced NLO response in terms of both the β and γ values was observed for C 4h isomer compared to the other isomers, smallest NLO response were observed for the C 2v and C s isomers, respectively.