Two 1-D Coordination Polymers containing Zinc(II) Hexaborates: [Zn(en){B6O7(OH)6}].2H2O (en = 1,2-diaminoethane) and [Zn(pn){B6O7(OH)6}].1.5H2O (pn = 1,2-diaminopropane)

The synthesis and characterization by single-crystal 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) centres and form 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.