Multifunctional Chiral d<SUP>10</SUP>-Metal Coordination Polymers: Tunable Photoluminescence and Efficient Second-Harmonic Generation with Circular Dichroic Response

초록

A series of homochiral coordination polymers (HCPs), [M-2(SIAP)(2)(bpy)(2)] [M(S)] and [M-2(RIAP)(2)(bpy)(2)] [M(R)] (M = Zn or Cd, SIAP or RIAP = (S,S)- or (R,R)- 2,2 '-(isophthaloylbis(azanediyl))di-propionic acid, bpy = 4,4 '-bipyridine), is successfully synthesized through solvothermal reactions, self-assembling d(10) metal cations, chiral dicarboxylic ligands, and pi-conjugated bipyridyl ligands. The HCPs crystallize in the extremely rare triclinic chiral space group, P1, and present 3D framework structures attributed to the strong intermolecular interactions, such as hydrogen bonds and pi-pi stacking. Due to the unique crystal structures, the title compounds reveal efficient photoluminescence emission across a broad visible range, with significant brightness and color tuning by varying the excitation wavelength. Moreover, they exhibit efficient phase-matched second-harmonic generation (SHG) with very high laser-induced damage thresholds, essential for high-power nonlinear optical (NLO) applications. Intriguingly, the title compounds exhibit a measurable contrast in the SHG response under right- and left-handed circularly polarized excitation, thereby providing a unique case of SHG circular dichroism from the chiral centers of SIAP(2-) or RIAP(2-) ligand packed in the noncentrosymmetric environment. These exceptional attributes position these HCPs as promising candidates for multifunctional materials, with potential applications ranging from NLO devices to tailored luminescent systems with polarization control.

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