Quantum chemical study on first hyperpolarizabilities of mono- and bimetal Pt(II) diimine complexes

The static first hyperpolarizabilities (βvec) of ligand L (N,N′-bis(4-methoxyphenyl)ethylenediimine) and its Pt(II) chelated complexes have been calculated by density functional theory (DFT) method. The results show that the βvec values of Pt(II) diimine complexes range from ∼4.2 to ∼198.8 times larger than that of ligand L, and the βvec values of Pt(II) complexes with coordinated atom O are larger than those of the corresponding complexes with S. Notably, the bimetallic complex 3a possesses the largest βvec value in the studied systems, ∼1498.86 × 10−30 esu, which is ∼46.6, ∼30.5, and ∼3.6 times as large as those of complexes 1a, 2a and 3b, respectively. In addition, the dynamic first hyperpolarizabilities (βvec(ω)) of complex 1a are also calculated at the input photon energy from 0.1 to 1.8 eV. Our present work would be beneficial for further theoretical and experimental studies on large second-order nonlinear optical (NLO) responses of metal complexes.