Two 1-D multi-nickel substituted arsenotungstate aggregates

Two multi-nickel substituted arsenotungstate aggregates [enH2]2[Ni(H2O)4]2[Ni(en)2]2[Ni(en)]2{[(α-AsW6O26)Ni6(OH)2(H2O)3(en)(B-α-AsW9O34)]2[W4O16][Ni3(H2O)2(en)]2}·16H2O (1) and [Ni(H2O)(en)2]2[Ni(H2O)3(en)][Ni(H2O)(en)]{[(α-AsW6O26)Ni6(OH)2(en)2.5(B-α-AsW9O34)]2H4[W4O16][Ni4(H2O)2(en)2]2}·13H2O (2) (en = ethylenediamine) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectra, UV spectra and single-crystal X-ray diffraction. 1 is a 1D chain architecture built by eighteen NiII substituted {[(α-AsW6O26)Ni6(OH)2(H2O)3(en)(B-α-AsW9O34)]2[W4O16][Ni3(H2O)2(en)]2}16− units via two [Ni(H2O)4]2+ and two [Ni(en)2]2+ bridges. 2 also displays a 1D chain motif constructed from twenty NiII substituted {[(α-AsW6O26)Ni6(OH)2(en)2.5(B-α-AsW9O34)]2H4[W4O16][Ni4(H2O)2(en)2]2}8− units via single en bridges. Notably, 1 and 2 not only represent rare eighteen/twenty NiII substituted arsenotungstates, but also display an unusual construction motif simultaneously containing the trivacant Keggin [B-α-AsW9O34]9−, hexavacant Keggin [α-AsW6O26]11− and tetrameric [W4O16]8− fragments. Magnetic measurements demonstrate that 1 and 2 indicate the ferromagnetic couplings within NiII centers.