A Rare Inorganic-Organic Hybrid Polyoxoboroniobate Based on Pagoda-Shaped {LiB 2 Nb 29 O 86 } Clusters and {Cd 2 ( cis -en) 2 ( trans -en)} Complexes.

A new inorganic-organic hybrid polyoxoboroniobate {H 4 K 2 [Cu( cis -en) 2 (H 2 O)] 9 [Cu( cis -en) 2 ] 6 [Cd 2 ( cis -en) 2 ( trans -en)][LiB 2 Nb 29 O 86 ] 2 ·79H 2 O} ( 1 , en = ethylenediamine), is built from pagoda-shaped {LiB 2 Nb 29 O 86 } clusters, linear {Cd 2 ( cis -en) 2 ( trans -en)} bridging units, and copper-amine complexes. The {LiB 2 Nb 29 O 86 } cluster represents the first example of combining oxoboron clusters with polyoxoniobate clusters (PONbs). It consists of an unusual HPONb fragment {LiNb 18 O 54 }, a fused-ring structural boroniobate cluster {B 2 Nb 5 O 13 }, and a classical Lindqvist {Nb 6 O 19 } fragment. The {Cd 2 ( cis -en) 2 ( trans -en)} and [Cu( cis -en) 2 ] 2+ complexes link the pagoda-shaped {LiB 2 Nb 29 O 86 } clusters into 1D infinite ladder chains. This is the first instance of simultaneous coordination of the cis -en and trans -en ligands with a single metal cation in the inorganic-organic hybrid PONb family. Furthermore, 1 exhibits good proton conductivity.