A DFT study on NLO response of push-pull hybrid porphyrin-polyoxometalate complexes

Density functional theory (DFT) calculations were carried out to investigate the second-order nonlinear optical (NLO) properties of a series of proposed porphyrin-polyoxometalate-based complexes related to [5-(3,5-dimethyl-4-hexamolybdate amino-phenyl-ethynyl)-15-(4-nitrophenyl-ethynyl)porphinato]zinc(II) which have donor-π conjugated bridge-acceptor (D-π-A) configurations. Our calculations show that these species possess considerably large molecular total second-order polarizability (β 0 ), ∼2000 × 10 −30 esu. Furthermore, it can be seen that {W 6 O 18 } exhibits stronger electron-donating ability than {Mo 6 O 18 }. And two-dimensional (2D) system with A-π-D-π-A structure might be a promising candidate for NLO materials based on the large β 0 (4583.5 × 10 −30 esu) and in-plane nonlinear anisotropy.