title: Complex open-framework germanate built by 8-coordinated Ge(10) clusters.
abstract: A novel open-framework germanate |(C5H14N2)2(C5H12N2)0.5(H2O)2.5|[Ge12.5O26(OH)2] with three-dimensional 10- and 11-ring channels, denoted as SU-67, has been synthesized under hydrothermal conditions using 2-methylpiperazine (MPP) as the structure-directing agent (SDA). The synthesis is intimately related to that of JLG-5, a tubular germanate built from Ge7 clusters. The influences of synthesis parameters are discussed. A strong influence of the hydrofluoric acid quantity on the resulting cluster building units can be concluded. The framework of SU-67 is based on an elaborate topological pattern of connected Ge10 clusters forming intersecting 10- and 11-ring channels and has a low framework density (12.4 Ge atoms per 1000 Å(3)). We have discovered that the topology of SU-67 is a new 8-connected nce-8-I41/acd net. Strong hydrogen bonding among the organic SDAs, water molecules, and Ge10 clusters resulted in helical networks in SU-67.
authors.affiliation: State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , 130012 Changchun, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Yue
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Peskov
authors.forename: Junliang
authors.initials: J
authors.lastname: Sun
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zou