In this research, two 4-styrylpyridines carrying an acceptor –NO
2 (
L1) or a donor –NMe
2 group (
L2) were axially coordinated to A
4 Zn
II porphyrins displaying in 5,10,15,20
meso position aryl moieties with remarkable electron withdrawing properties
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In this research, two 4-styrylpyridines carrying an acceptor –NO
2 (
L1) or a donor –NMe
2 group (
L2) were axially coordinated to A
4 Zn
II porphyrins displaying in 5,10,15,20
meso position aryl moieties with remarkable electron withdrawing properties (pentafluorophenyl (
TFP)), and with moderate to strong electron donor properties (phenyl (
TPP) < 3,5-di-
tert-butylphenyl (
TBP) < bis(4-
tert-butylphenyl)aniline) (
TNP)). The second order nonlinear optical (NLO) properties of the resulting complexes were measured in CHCl
3 solution by the Electric-Field-Induced Second Harmonic generation technique, and the quadratic hyperpolarizabilities β
λ were compared to the Density Functional Theory (DFT)-calculated scalar quantities β
||. Our combined experimental and theoretical approach shows that different interactions are involved in the NLO response of
L1- and
L2-substituted A
4 Zn
II porphyrins, suggesting a role of backdonation-type mechanisms in the determination of the negative sign of Electric-Field-Induced Second Harmonic generation (EFISH) β
λ, and a not negligible third order contribution for
L1-carrying complexes.
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