Synthesis and characterization of polyborates templated by cationic copper(II) complexes: structural (XRD), spectroscopic, thermal (TGA/DSC) and magnetic properties.

The synthesis and X-ray diffraction structure of [Co(en)3][B5O6(OH)4][B8O10(OH)6]·5H2O (1) are reported. Compound 1 arises through a selective-templating process from a Dynamic Combinatorial Library of polyborate anions. Compound 1 contains two different polyborate species, with [B8O10(OH)6](2-) being particularly novel. It is comprised of fused tetraborate and pentaborate anions with a 4-coordinate B atom and a 3-coordinate O atom in common.

The unusual [Cu 7 (NH 3) 2 (H 2 O) 4 {B 24 O 39 (OH) 12 }] 4cluster anion, isolated in the form of its hydrated hydronium ion salt, has been crystallized in moderate yield (59%) through a templated self-assembly process from [Cu(NH 3) 4 (H 2 O) 2 ](OH) 2 and B(OH) 3 (10 equivalents) in aqueous solution. This novel anionic cluster is comprised of two diborate(2-) ligands bridging a linear {Cu 3 } 6? framework with this Cu 3 fragment interacting with, and further supported by, a known larger [{Cu 4 O}B 20 O 32 (OH) 8 ] 6cluster.

The synthesis and characterization by single-crystal X-ray diffraction (XRD) studies of two new zinc(II) hexaborate(2−) complexes, [Zn(en){B6O7(OH)6}]·2H2O (en = 1,2-diaminoethane) (1) and [Zn(pn){B6O7(OH)6}]·1.5H2O (pn = 1,2-diaminopropane) (2), are reported. These complexes crystallize from aqueous solutions containing 10:1 ratios of B(OH)3 and the appropriate Zn(II) amine complexes ([Zn(en)3][OH]2 or [Zn(pn)3][OH]2) through self-assembly processes. The hexaborate(2−) anions in 1 and 2 are coordinated to two Zn(II) centers and form one-dimensional (1-D) polymeric coordination chains. R22(8) and R22(6) inter-chain H-bond interactions play an important role in these self-assembly processes and are discussed.