Ambient-Temperature Synthesis of New Layered AlPOs and GaPOs in Silica Gels

• Published in: Chemistry of materials 1998-01, Vol.10 (1), p.451-456
• Main Authors: Leech, Michael A, Cowley, Andrew R, Prout, Keith, Chippindale, Ann M
• Format: Article
• Language: English
• Subjects: Chemistry; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; General and physical chemistry; Inorganic compounds; Ion-exchange; Physics; Salts; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Surface physical chemistry; Zeolites: preparations and properties
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm970650a

A method for synthesising open-framework phosphates under less-severe conditions than those employed in conventional solvothermal processes is described. Two new layered aluminum phosphates containing pyridine and imidazole templates and their gallium analogues have been grown in silica gel at room temperature, and the structures determined by single-crystal X-ray diffraction. Crystal data:  general formula (C5NH6)[M(HPO4)2(H2O)2], triclinic, space group P1̄, lattice parameters a = 6.994(1), b = 7.2208(7), c = 12.114(1) Å, α = 105.080(8), β = 104.85(1), γ = 90.39(1)° when M = Al; a = 7.056(1), b = 7.315(1), c = 12.165(1) Å, α = 105.32(1), β = 105.49(1), γ = 90.25(1)° when M = Ga. General formula (C3N2H5)[M(HPO4)2(H2O)2], monoclinic, space group C2/c, a = 21.893(1), b = 7.1830(3), c = 6.9890(5) Å, β = 104.164(5)° when M = Al; a = 22.002(2), b = 7.262(1), c = 7.047(1) Å, β = 105.11(1)° when M = Ga. The four structures are closely related and contain MO6 (M = Al, Ga) and PO4 polyhedra linked to form corrugated layers. The pyridinium or imidazolium cations occupy sites between these layers and are linked through hydrogen bonding to one or two adjacent layers, respectively.