Synthesis and crystal structures of (NH3CH2CH2NH3)(1.5) [(VO)(2)(HPO4)(2)(PO4)] and (C4H12N2)(2)[V4O6H(HPO4)(2)(PO4)(2)], two layered vanadium phosphates templated with organic diamines

摘要

Two new layered vanadium phosphates templated by ethylenediamine, (NH3CH2CH2NH3)(1.5)[(VO)(2)(HPO4)(2)(PO4)] (1), and piperazine, (C4H12N2)(2)[V4O6H(HPO4)(2)(PO4)(2)] (2), have been synthesized hydrothermally and their structures determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space group C2/c (no. 15) with a = 18.6051(5), b = 7.1193(1), c = 23.4597(7) Angstrom, beta = 96.558(2)degrees, V = 3087.03 Angstrom(3), Z = 8, and R1 = 0.0583. The structure consists of infinite chains of traps-corner-shared VO6 octahedra, which are bridged by phosphate groups. The infinite chains are connected by VO5 square pyramids via V-O-P bonds to form layers with 10-sided windows. Adjacent layers are aligned such that infinite tunnels along the [001] direction are generated. Ethylenediammonium cations are located at sites both in the interlayer space and in the windows within the layers. Crystal data for 2: orthorhombic, space group Pna2(1) (no. 33), a = 13.1812(6), b = 15.2918(8), c = 6.2821(3) Angstrom, V = 1266.25 Angstrom(3), Z = 2, and R1 = 0.0367. Compound 2 is a mixed-valence V-IV/V-V vanadium phosphate as was confirmed by magnetic susceptibility measurements. (VO6)-O-IV octahedra connected via HPO4 groups form a double chain, which alternates with a chain of traps-corner-shared square pyramids containing an infinite V-IV-O-V-V-O motif. Both chains are connected through phosphate groups to form a layer, which contains 14-membered empty windows. Piperazinium dications are anchored in the interlayer space. (C) 2003 Elsevier Science (USA). All rights reserved. [References: 21]