Surfactant-Templated Inorganic Lamellar and Non-Lamellar Hybrid Phases Containing Adamantane [Ge₄Se₁₀]^4- Anions

The metathesis reaction of K 4 Ge 4 Se 10 with various alkyl tri- and dimethylammonium halides [C n H 2 n +1 N(CH 3 ) 3 - m H m ]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 [Ge 4 Se 10 ]. 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 -C 8 H 17 N(CH 3 ) 3 ] 4 Ge 4 Se 10 (C8−GeSe), monoclinic, space group C 2/ c, Z = 4, a = 34.2324(9) Å, b = 10.9213(3) Å, c = 19.2700(5) Å, β = 104.567°; nonyltrimethylammonium decaselenotetragermanate [ n -C 9 H 19 N(CH 3 ) 3 ] 4 Ge 4 Se 10 (C9−GeSe), triclinic, space group P 1̄, 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 -C 8 H 17 N(CH 3 ) 2 H] 4 Ge 4 Se 10 (ODA−GeSe) tetragonal, space group I 1 / a, Z = 4, a = 18.6462(1) Å, c = 19.2038(1) Å. C8−GeSe and C9−GeSe are composed of parallel layers of [Ge 4 Se 10 ] 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 (Se t ) of the adamantane cluster are unusually short (2.38(5) Å), leading to strong N−H···Se hydrogen bonds. [( n -C 4 H 9 ) 3 NH] 4 Ge 4 Se 10 has a very similar arrangement of the organic/inorganic building units to that of ODA−GeSe, including the strong N−H···Se hydrogen bonds.