A series of new 3-D boratopolyoxovanadates containing five types of [KxOy]n building units†
Abstract
A series of new 3-D boratopolyoxovanadates {K2V12B18O54(OH)6(H2O)[K8(H2O)16]}·3H2O (1), {K10V12B18O54(OH)6(H2O)}·14H2O (2), {V12B18O54(OH)6(H2O)[K6(H2O)12]}·2(H2dien)·3H2O (3, dien = diethylenetriamine), {V6B20O44(OH)8(H2O)[K8(H2O)6]} (4), and {V6B20O44(OH)8(H2O)[K(H2O)]2}·2(H3dien)·6H2O (5) have been hydrothermally synthesized and structurally characterized. These compounds contain five types of [KxOy]n building units, namely, a dimeric [K2O16] unit for 5, a 1-D [K3O12]n chain for 3, a 3-D [K5O10]n sub-network for 1, a 3-D [K5O12]n sub-network for 2, and a 3-D [K4O7]n sub-network for 4. The 3-D frameworks of both 1 and 2 are built up from a different 3-D inorganic [KxOy]n sub-network and entrapped [V12B18O54(OH)6(H2O)]10− (denoted as [V12B18]) clusters, respectively. 3 contains [V12B18] clusters and 1-D [K3O12]n chains, which are interconnected to form a 3-D {V12B18O54(OH)6(H2O)[K6(H2O)12]}n architecture with 1-D tunnels filled with protonated H2dien2+ ions. The 3-D architecture of 4 is constructed by another rare 3-D inorganic [K4O7]n sub-network and entrapped [V6B20O44(OH)8(H2O)] (denoted as V6B20) clusters. Compounds 1, 2 and 4 represent rare examples of extended POVs with the 3-D inorganic [KxOy]n sub-networks. 5 contains [V6B20] clusters and dimeric [K2O16] units, which are interconnected to give a 3-D {B20V6O44(OH)8(H2O)[K(H2O)]2}n architecture with 1-D tunnels filled with protonated H3dien3+ ions. Although a few boratopolyoxovanadates contain the [V6B20] cluster, they display either a discrete [V6B20] cluster or a low-dimensional extended structure. Therefore, both 4 and 5 are rare examples of 3-D boratopolyoxovanadate architectures based on the [V6B20] clusters. The magnetic susceptibilities of both 4 and 5 show the antiferromagnetic interaction between VIV cations. Their spectroscopic properties were also investigated.