Synthesis and characterisation of a new vanadyl oxalatophosphate compound: (C 10 H 10 N 2 )[(VO)(HPO 4 )] 2 (C 2 O 4 ) Fa-Nian Shi a , Filipe A. Almeida Paz a,b, * , Joa ˜o Rocha a , Jacek Klinowski b , Tito Trindade a, * a Department of Chemistry, CICECO, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro, Portugal b Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK Received 21 May 2004; accepted 4 October 2004 Available online 13 November 2004 Abstract A new vanadyl oxalatophosphate compound, (C 10 H 10 N 2 )[(VO)(HPO 4 )] 2 (C 2 O 4 ), was synthesized via the hydrothermal approach and characterised structurally using single-crystal X-ray diffraction, FT-IR and thermogravimetric analysis. The compound has two- dimensional f½ðVOÞðHPO 4 Þ 2 ðC 2 O 4 Þg n 2n anionic layers with C 10 H 10 N 2 2þ occupying the interlayer spaces. Ó 2004 Elsevier B.V. All rights reserved. Keywords: Vanadyl oxolatophosphate; Hybrid material; Crystal structure 1. Introduction Considerable effort has been made in the predic- tion, design and synthesis of novel open-framework inorganic-organic hybrid materials because of their peculiar architectures and interesting potential applica- tions. The rich coordination chemistry of vanadium, which can exhibit several coordination geometries and several oxidation states, is directly reflected in the large variety of frameworks where metal centres are combined with tetrahedral groups (e.g., phosphate anions) or organic bridging ligands (e.g., oxalate ani- ons) [1–3]. Since the final properties of a given product are related to the chemical composition as well as to the connectivity of the framework, study of the synthe- sis of hybrid vanadium-based materials is of funda- mental importance. Despite reports on several monometallic [4–14] and bimetallic [15–22] discrete complexes, and on polyoxo- vanadates [23–26] containing oxalate anions, only a handful of one-dimensional (1D) [20,27,28] and two- dimensional (2D) [29–31] hybrid inorganic-organic materials have been described [32]. Following our recent interest in novel multidimensional hybrid materials con- taining a variety of metal centres and bridging organic ligands [33–40], we wish to report the hydrothermal syn- thesis and structural characterisation of a novel vanadyl oxalatophosphate layered compound, (C 10 H 10 N 2 )[(VO)- (HPO 4 )] 2 (C 2 O 4 ), which shares striking structural simi- larities with the materials reported by Do et al. [30,31]. 2. Experimental All chemicals were readily available from commercial sources and were used as received without further puri- fication. Syntheses were carried out in PTFE-lined stain- less steel reaction vessels (40 cm 3 ) under autogeneous pressure and static conditions. 0020-1693/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ica.2004.10.017 * Corresponding authors. Tel.: +351 234 370 726; fax: +351 234 370 084 (T. Trindade); Tel.: +44 1223 762079; fax: +44 1223 336507 (F.A. Almeida Paz). E-mail addresses: fpaz@dq.ua.pt (F.A. Almeida Paz), ttrinda- de@dq.ua.pt, ttrindade@dq.ua.pt (T. Trindade). www.elsevier.com/locate/ica Inorganica Chimica Acta 358 (2005) 927–932