Two new hexa-Ni-substituted polyoxometalates in the form of an isolated cluster and 1-D chain: syntheses, structures, and properties.

Two new hexa-Ni-substituted polyoxometalates (POMs), [Ni6(μ3-OH)3(en)2(dien)(H2O)5(B-α-PW9O34)]·3H2O (1, en = ethylenediamine, dien = diethylenetriamine) and [Ni6(μ3-OH)3(dap)2(py)6(H2O)(B-α-PW9O34)]·H2O (2, dap = 1,3-diaminopropane, py = pyridine), were successfully isolated under hydrothermal conditions. Compounds 1 and 2 were structurally characterized via single-crystal X-ray diffraction (XRD), infrared (IR) spectrometry, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Single-crystal X-ray structure analyses indicate that the {Ni6PW9} cluster units were modified via different organic ligands through Ni–N bonds, giving rise to the formation of 1 and 2. Interestingly, the formation of 1 involves new in situ ligand reactions under hydrothermal conditions: the intermolecular deamination coupling reactions of en. Compound 2 is a new Z-shaped 1-D chain, which is connected by Ni–O＝W bonds from two adjacent [Ni6(μ3-OH)3(dap)2(py)6(H2O)(B-α-PW9O34)] units. In addition, their photocatalytic activities, and electrochemical and magnetic properties have been investigated. [ABSTRACT FROM AUTHOR]