Two one-dimensional mono-substituted heteropolytungstates based on Keggin anion units

Two kinds of complexes [Ni(DETA)2]3[SiNiW11O39]·2.5H2O (DETA=diethylenetriamine) (1) and <f>[H2en]2[Ba0.15(H2O)2(Hen2)]H1.7[SiNaW11O39]·2H2O</f> (2) were obtained from the hydrothermal reaction and characterized by single crystal X-ray diffraction analysis and IR spectra. Crystal data: C24H83N18Ni4O41.5SiW11 (1), monoclinic, P<f>n</f>, <f>a=10.926(2)</f> Å, <f>b=23.022(5)</f> Å, <f>c=13.221(3)</f> Å, <f>β=94.27(3)</f>°, <f>V=3316.4(11)</f> Å3, <f>Z=2</f>; C8H46.7N8Ba0.15NaO43SiW11 (2), monoclinic, P21, <f>a=12.840(3)</f> Å, <f>b=11.174(2)</f> Å, <f>c=16.693(3)</f> Å, <f>β=91.14(3)</f>°, <f>V=2394.4(8)</f> Å3, <f>Z=2</f>. Both of them consists of one mono-substituted Keggin unit [SiMW11O39](8-n)- (M&z.dbnd;Ni, Na, n=2, 1) obtained by metal atom substituting for a W atom from the plenary anion [SiW12O40]4-. This unit then connects with other adjacent units via M–O–W bridges constructing an infinitely one-dimensional chain-like structure in which the metal cation and polyanion alternate. Moreover, both of Ni or Na atoms are in a distorted octahedral environment with six oxygen atoms and occupy one position in the oxometalate shell of the Keggin structure. [Copyright &y& Elsevier]