Crystallization of zinc azole complex incorporated Strandberg-type cluster-based solids: Synthesis, structure and photoluminescence studies

Abstract

Two new zinc azole complexes incorporated Strandberg-type cluster-based solids, namely (Hpz)6{Zn(pz)4(H2O)2}[{Zn(pz)2P2Mo5O23}2]8H2O (1) and (Himi)4{Zn(imi)3P2Mo5O23}7H2O (2) were crystallized using isomeric azole ligands, i.e., pyrazole (pz) and imidazole (imi), respectively. While solid 1 crystallized in triclinic system with space group P-1 with cell parameters a = 9.5647(15), b = 12.558(2), c = 20.340(3) A˚ , a = 75.907(7), b = 84.727(6), c = 87.525(7), Z = 1; 2 crystallized in orthorhombic system with space group P212121 having cell parameters a = 12.048(3), b = 19.561(5), c = 20.732(5) A˚ , Z = 4. Both pyrazole and imidazole can form a complex with zinc centres to form an extended solid in 1 and a derivatized Strandberg-type cluster in 2. Interestingly, 1 is a new supramolecular isomer of previously reported solid viz., (pz)[{Zn(pz)3}3{P2Mo5O23}]2H2O and 2 is the only example wherein a zinc imidazole complex has derivatized a Strandberg-type cluster. Detailed structure analysis of 1 and 2 was carried out, and the role of tectons in dictating the self-assembly of these solids was evaluated. In addition, a solid-state photoluminescence study was carried out for 1 and 2 at room temperature.