A new sandwiched polyoxometalate[HK11Cd4Cl2(PW9O34)2]·18H2O(1),incorporating a unique hybrid tetranuclear cadmium cluster(abbreviated to{Cd4})with two trivacant polyanions[B-α-PW9O34]9-,has been hydrothermally synthesized and structurally characterized by elemental analyses,IR spectroscopy,UV-vis,and single-crystal X-ray diffraction analysis.Crystal data for 1:monoclinic,space group C2/c,a=19.2997(4),b=13.8014(3),c=31.9819(8),β=102.764(2)o,V=8308.3(3)3,Z=4,P2O86Cl2K11Cd4W18H37,Mr=5735.13,Dc=4.584 mg·mm-3,F(000)=10084,μ=26.579 mm-1,the final R=0.0378 and wR=0.0989 for 6558 observed reflections(I>2σ(I)).X-ray crystallographic study shows that the molecular structure of 1 contains four cadmium atoms.Two CdO6distorted octahedra and two CdO5Cl distorted octahedra combine with each other in turn via edge-sharing,resulting in a regular rhomb-like cluster sandwiched between two{B-α-PW9O34}units.Further,the sandwich-type polyoxoanions were connected by K+ions to form a complicated 3-D open-framework through connecting with each terminal O atom of the[Cd4Cl2(PW9O34)2]12-polyoxoanions.In addition,compound 1 exhibits photoluminescence property at room temperature and the band gap can be assessed at 3.25 eV.
FAN Shu-GeZHANG XiaoZHANG Nan-XiYI Zhi-HuiLIU LeiHUANG Yan-Ping
A supramolecular compound(C6H6NO2)3(C6H5NO2)(PW12O40)·2H2O including the Keggin-type[PW12O40]3-polyanion,[HC6H5NO2]+(protonated pyridine-4-carboxylic acid molecule),C6H5NO2(pyridine-4-carboxylic acid molecule)and two free H2O molecules has been synthesized by the hydrothermal method and characterized by elemental analysis,IR spectra,single-crystal X-ray diffraction and powder X-ray diffraction.The crystal belongs to orthorhombic,space group Pnnm with a=1.0483(3),b=1.4368(6),c=2.0526(7)nm,V=3.0918(18)nm3,Z=2,F(000)=3004,Mr=3406.07,Dc=1.757 g·m-3,μ=41.241 mm-1,the final R=0.0387 and wR=0.1089 for2091 observed reflections with I>2σ(I).A total of 30431 reflections were collected,of which 3083were independent(Rint=0.0605).S is 1.182.The title compound presents a 3-D structure via intermolecular hydrogen bonds among[PW12O40]3-polyanions and pyridine-4-carboxylic acid ligands.The ultraviolet and luminescence spectra have been studied at room temperature,of which the purple fluorescent emission is located at 363 nm when excited at 264 nm.Fluorescent emission of the compound derives from theπ-π*transitions in the pyridine-4-carboxylic acid ligands.
LIU LeiXU Xian-ZhuZHANG XiaoZHANG Nan-XiFAN Shu-GeHUANG Yan-Ping
