Abstract

Two novel Mn(II) coordination polymers [Mn(N₃)₂(bbp)₂]_n1 and {[Mn(NCS)₂(bbp)₂]·0.25H₂O}_n2 (bbp = 4,4′-trimethylenedipyridine) with 2D double-sheet layered structures were obtained by a normal synthesis method at room temperature. Interestingly, each layer contains two sheets; the double-sheet layer is formed around an octahedral coordination center, Mn(II), with bbp ligands knitted into each other. The structures both contain channels with dimensions of about 6.5 × 6.5 Å for 1 and 6.7 × 6.0 Å for 2. Both compounds have a similar construction, giving the same third-order nonlinear optical (NLO) behavior and weak antiferromagnetic properties. Their third-order NLO refractive indexes n₂ are 1.21 × 10⁻¹⁸ m² W⁻¹ for 1 and 6.71 × 10⁻¹⁹ m² W⁻¹ for 2. The NLO susceptibilities χ⁽³⁾ were calculated to be 4.78 × 10⁻¹² esu and 2.40 × 10⁻¹² esu, respectively.