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Journal of Spectroscopy
Volume 2013 (2013), Article ID 378379, 9 pages
http://dx.doi.org/10.1155/2013/378379
Research Article

Structures and Spectroscopy Studies of Two M(II)-Phosphonate Coordination Polymers Based on Alkaline Earth Metals (M = Ba, Mg)

1Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, China
2Department of Criminal Science and Technology, Jilin Police College, Changchun 130117, China

Received 29 June 2012; Revised 6 September 2012; Accepted 14 September 2012

Academic Editor: Xuezhong Du

Copyright © 2013 Kui-Rong Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The two examples of alkaline-earth M(II)-phosphonate coordination polymers, [Ba2(L)(H2O)9]·3H2O (1) and [Mg1.5(H2O)9]·(L-H2)1.5·6H2O (2) (H4L = H2O3PCH2N(C4H8)NCH2PO3H2), N,N′-piperazinebis(methylenephosphonic acid), (L-H2 = O3PH2CHN(C4H8)NHCH2PO3) have been hydrothermally synthesized and characterized by elemental analysis, FT-IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Compound 1 possesses a 2D inorganic-organic alternate arrangement layer structure built from 1D inorganic chains through the piperazine bridge, in which the ligand L−4 shows two types of coordination modes reported rarely at the same time. In 1, both crystallographic distinct Ba(1) and Ba(2) ions adopt 8-coordination two caps and 9-coordination three caps triangular prism geometry structures, respectively. Compound 2 possesses a zero-dimensional mononuclear structure with two crystallographic distinct Mg(II) ions. Free metal cations and uncoordinated anions - are joined together by static electric force. Results of photoluminescent measurement indicate three main emission bands centered at 300 nm, 378.5 nm, and 433 nm for 1 and 302 nm, 378 nm, and 434.5 nm for 2 (  nm), respectively. The high energy emissions could be derived from the intraligand transition stations of (310 nm and 382 nm,  nm), while the low energy emission (>400 nm) of 1-2 may be due to the coordination effect with metal(II) ions.