Abstract: A novel 12-ring network coordination polymer, {[Cu(C₄N₂H₁₀)₄]₂H₄V₄O₁₄}_n(denoted as QUST-4), was hydrothermally synthesized and structurally determined by X-ray single-crystal diffraction analysis. QUST-4 was crystallized in a monoclinic system with space group P2₁/n. The parameters of the unit cell are a=1.0497(2) nm, b=1.6728(3) nm, c=1.2857(3) nm, β=94.14(3)°, V=2.2517(8) nm³, Z=4, D_cal= 1.841 Mg/m³, R₁=0.1071, and wR₃=0.2703. The largest difference peak and hole were 2284 and -1040 e/nm³, respectively. The SBU(secondary building unit) of QUST-4 was a new cyclo-aggregate of polyoxovanadate cyclo-[H₄V₄O₁₄]^4-, different from cyclo-[V₄O₁₂]^4-, which was condensed from two tetrahedral and two trigonal bipyramids via alternate {arrangement.} Cu(piper)₄(piper=piperazine) group connected the cyclo-[H₄V₄O₁₄]^4- anions to form the 12-ring network. The adjacent layers were linked by van der Walls forces.

Key words: Coordination polymer, Aggregate of polyoxovanadate, Hydrothermal synthesis, Network