Two Unprecedented Germanoniobate Frameworks Based on High-Nuclearity Peanut-Shaped {Ge₁₂Nb₃₈} Clusters

By variation of the amount of GeO2, two organic-inorganic hybrid germanoniobate frameworks with 6-connected pcu and 10-connected bct topologies were constructed from peanut-shaped {alpha-Ge12Nb38} and {beta-Ge12Nb38} clusters, respectively. The {alpha-Ge12Nb38} and {beta-Ge12Nb38} clusters contain the most Ge centers of germanoniobates reported so far. The compounds exhibit proton conduction properties with a conductivity of 3.04 x 10(-4) Scm(-3) for 1 and 1.62 x 10(-4) Scm(-3) for 2 at 85 degrees C and 98% RH. The water vapor adsorption capacities for 1 and 2 are 5.86 and 4.40 mmolg(-1), respectively.