Synthesis,Crystal Structure and Calculated β Value of a Tetrahedral Zinc (II) Complex——Zn(2-NH_2py)_2Br_2

1 INTRODUCTION Coordination chemistry has been playing an important role in nonlinear optical (NLO) materi- als 1~3] in recent years. It has been found that tetrahedral or square pyramidal molecular configurations are useful for designing transparent second-harmonic generation (SHG) materials from coordination compounds4]. It has also been reported that the pyridyl-based metal complexes can exhibit SHG effects5]. Recently, we have successfully synthesized a new coordination compoun…

Synthesis, Crystal Structure and Calculated β Value of a Tetrahedral Zinc (II) Complex-Zn(2-NH2py)2Br2

A new zinc(II) complex, Zn(2-NH2py)2Br2 (py=pyridine), has been synthesized, and its molecular structure has been confirmed by IR, elemental analysis and Х-ray crystal structure analysis. Its space group is P21/n with Mr=413.43 (C10H12Br2N4Zn), a=7.435(2), b=12.865(3), c=14.186(4)A, β=94.08(2)°, V=1353.5(5) A3, Z=4, Dc=2.029 g/cm3, F(000)=328, μ=2.378mm-1, R=0.0283, wR=0.0501. The total observed reflections with I≥2σ(I) were 5314, of which the independent reflections were 3106. The complex structure contains a distorted tetrahedron formed by four atoms coordinated to zinc atom, namely two bromide atoms and two nitrogen atoms. The two Zn-Br bond lengths within one molecule, 2.3763(6) and 2.4002(5)A respectively, are not equal; and so are the two Zn-N bond lengths, which are 2.031(2) and 2.044(2)A respectively. The calculation results using PM3 method through MOPAC software package in Chem 3D show that its first molecular hyperpolarizability β value is 5.2×10-30esu, which is comparable with that of p-nitroaniline. No bulk SHG effect has been detected due to the centrosymmetric space group.