Chemistry: A European Journal 2003-10-17

Characterisation of four new two-dimensional lithium beryllofluoro-layered compounds.

Lee A Gerrard, Mark T Weller

Index: Chemistry 9(20) , 4936-42, (2003)

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Abstract

Four new amine-templated materials, containing two-dimensional lithium beryllofluoride sheets of the stoichiometry [LiBeF(4)](-), have been synthesised under hydrothermal and ambient pressure conditions. [LiBeF(4)][C(6)H(4)(CH(3))CH(2)NH(3)] (1), [LiBeF(4)][C(6)H(4)CH(2)NH(3)Cl] (2), [LiBeF(4)](2)[NH(3)CH(2)CH(2)CH(2)NH(3)] (3), and [LiBeF(4)][C(6)H(5)CH(2)CH(2)CH(2)NH(3)] (4) all contain well-separated anionic sheets containing two different topologies with the 'inter-layer' regions comprising of organoamine templating species. Use of the different organoamine templating agents results in compounds possessing very different relative arrangements of the lithium beryllofluoride sheets. The materials crystallise in P-centred orthorhombic and monoclinic cells; for 1 (templating agent: 3-methylbenzylamine) Pca2(1); for 2 (4-chlorobenzylamine) Pbca; for 3 (1,3-diamminopropane) Pccn, and for 4 (3-phenyl-1-propylamine) P2(1)/c. Hydrogen bonding exists between ions situated on the protonated amine groups on the templating species and electronegative fluoride ions, on MF(4) tetrahedra (where M=Li and Be).