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Surfactant-Templated Inorganic Lamellar and Non-Lamellar Hybrid Phases Containing Adamantane [Ge 4 Se 10 ] 4 - Anions

2000; American Chemical Society; Volume: 12; Issue: 10 Linguagem: Inglês

10.1021/cm000102o

1520-5002

Michael Wachhold, Mercouri G. Kanatzidis,

Polyoxometalates: Synthesis and Applications

The metathesis reaction of K4Ge4Se10 with various alkyl tri- and dimethylammonium halides [CnH2n+1N(CH3)3-mHm]X (n = 8, 9, 10, 12, 14, 16, 18; m = 0, 1; X = Cl, Br) led to several new surfactant−inorganic template phases containing selenogermanate adamantane units [Ge4Se10].4- The crystal structures of phases with shorter alkylammonium chains (n = 8 and 9) have been determined by single-crystal X-ray crystallography; octyltrimethylammonium decaselenotetragermanate, [n-C8H17N(CH3)3]4Ge4Se10 (C8−GeSe), monoclinic, space group C2/c, Z = 4, a = 34.2324(9) Å, b = 10.9213(3) Å, c = 19.2700(5) Å, β = 104.567°; nonyltrimethylammonium decaselenotetragermanate [n-C9H19N(CH3)3]4Ge4Se10 (C9−GeSe), triclinic, space group P1̄, Z = 2, a = 10.7799(2) Å, b = 18.1172(3) Å, c = 19.0075(1) Å, α = 91,881(1)°, β = 90.017(1)°, γ = 98.767(1)°; octyldimethylammonium decaselenotetragermanate [n-C8H17N(CH3)2H]4Ge4Se10 (ODA−GeSe) tetragonal, space group I1/a, Z = 4, a = 18.6462(1) Å, c = 19.2038(1) Å. C8−GeSe and C9−GeSe are composed of parallel layers of [Ge4Se10]4- anions in a pseudohexagonal arrangement, separated by the charge-balancing surfactant cations. While C9−GeSe contains bilayers of parallel interdigitating surfactant hydrocarbon chains, the shorter chains in C8−GeSe show a crisscross-like arrangement. The presence of hydrogen bonds in ODA−GeSe leads to the formation of a novel nonlamellar phase with isolated adamantane clusters whereby each is surrounded by four surfactant molecules. At the inorganic−organic interface, the Se···H contacts of the surfactant cations to the terminal Se atoms (Set) of the adamantane cluster are unusually short (2.38(5) Å), leading to strong N−H···Se hydrogen bonds. [(n-C4H9)3NH]4Ge4Se10 has a very similar arrangement of the organic/inorganic building units to that of ODA−GeSe, including the strong N−H···Se hydrogen bonds.