Charge density matching in templated molybdates

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.02.032· OSTI ID:21370413

Casalongue, Hernan Sanchez; Choyke, Sarah J ^[1]; Narducci Sarjeant, Amy ^[2]; Schrier, Joshua ^[1]

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1. Department of Chemistry, Haverford College, Haverford, PA 19041 (United States)
2. Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218 (United States)

The role of charge density matching in the formation of templated molybdates under mild hydrothermal conditions was investigated through the use of a series of structurally related amines: piperazine, 1,4-dimethylpiperazine, 2,5-dimethylpiperazine and 2,6-dimethylpiperazine. A series of reactions was conducted in which the relative mole fractions of each component were fixed at 2.5 MoO{sub 3}:1 amine:330 H{sub 2}O:2 H{sub 2}SO{sub 4} in order to isolate the effects of the amine, the only variation between reactions was the structure of the amine. Four distinct polyoxomolybdates anions were observed, ranging from zero-dimensional beta-[Mo{sub 8}O{sub 26}]{sup 4-} molecular anions to [Mo{sub 3}O{sub 10}]{sub n}{sup 2n-} and [Mo{sub 8}O{sub 26}]{sub n}{sup 4n-} chains and [Mo{sub 5}O{sub 16}]{sub n}{sup 2n-} layers. The primary influence over the structure of the molybdate anion is charge density matching with the protonated amine, which was quantified through surface area approximations based upon both calculated molecular surfaces and polyhedral representations of each anion. Secondary influences include amine symmetry and hydrogen-bonding preferences. The synthesis and characterization of two new compounds are reported. Crystal data: [C{sub 6}H{sub 16}N{sub 2}][Mo{sub 3}O{sub 10}].H{sub 2}O (1), triclinic, P-1 (no. 2), a=8.0973(7) A, b=8.8819(9) A, c=11.5969(11) A, alpha=71.362(9){sup o}, beta=82.586(8){sup o}, gamma=74.213(8){sup o}, Z=2, R/R{sub w}=0.0262/0.0564, and [C{sub 6}H{sub 16}N{sub 2}]{sub 2}[Mo{sub 8}O{sub 26}] (2), monoclinic, P2{sub 1}/n (no. 14), a=7.9987(11) A, b=12.5324(19) A, c=16.003(3) A, beta=97.393(14){sup o}, Z=2, R/R{sub w}=0.0189/0.0454. - Graphical abstract: A geometric decomposition method for surface area determination is presented in the context of charge density matching in new organically templated polyoxomolybdates.

• OSTI ID: 21370413
• Journal Information: Journal of Solid State Chemistry, Vol. 182, Issue 6; Other Information: DOI: 10.1016/j.jssc.2009.02.032; PII: S0022-4596(09)00092-9; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMINES
ANIONS
CHARGE DENSITY
DECOMPOSITION
MOLYBDATES
MOLYBDENUM OXIDES
MONOCLINIC LATTICES
PIPERAZINES
SURFACE AREA
SURFACES
SYNTHESIS
TRICLINIC LATTICES
AZINES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
HETEROCYCLIC COMPOUNDS
IONS
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYRAZINES
REFRACTORY METAL COMPOUNDS
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS