W0357
Ab-Initio Powder Structure Determination of Two New
Cadmium and Zinc N,N’-Ethylene Diammonium Methylenephosphonates, Naima
Bestaoui and Abraham Clearfield, Chemistry Dept., Texas A&M Univ. ,College
Station, Texas 77843-3255.
Metal phosphonates are of considerable interest because of
their potential application in catalysis1, ion exchange2,
intercalation3 and many other fields4. These compounds
present generally a layered structure. The metal atoms and the bridging oxygen
atoms from the phosphonate groups form the layers. The organic moiety occupies
the interlayer spacing.
One general ligand that has been used in our group is
α,ω-alkyldiphosphonic
acid. The resulting metal phosphonates form layered structures in which the
layers are cross-linked by the alkyl groups5. By inserting imine
groups in the alkyl chains, it Imports ion exchange and complexing ability to
the compounds6.
Divalent metals often form crystalline phosphonates. It was of
interest to prepare cross-linked layers containing the amino-functionality.
Determination of such structures would provide a mechanism for understanding the
ion exchange and complexion reactions via structural data.
In this communication, we present the crystal structures of
cadmium and zinc ethylenediamine phosphonates as determined from X-ray powder
data. These two compounds have layered structures, which are maintained by
hydrogen bonding. The structures were determined and refined by using the two
programs EXPO and GSAS.
References
1Cheng, S.; Peng, G. –Z; Clearfield, A. Ind.
Eng. Chem. Prod. Res. Dev. 1984, 23, 2.
2Wang, J. D.; Clearfield, A.; Peng, G. –Z
Mater. Chem. Phys. 1993, 35, 208.
3Alberti, G.; Costantino, U. In Comprehensive
Supramolecular Chemistry; Lehn, J.M., Ed.; Pergamon-Elsevier Science Ltd:
London, 1996, p 1.
4(a) Stein, E.; Clearfield, A.; Subramanian, M.A.
Solid State Ionics 1996, 83, 113.(b) Cao, G.; Hong, H.; Mallouk, T.E.
Acc. Chem. Res.1992, 25, 420 (c) Vermeulen, L.A.; Thompson, M.E. Nature
1992, 358, 656.
5(a) Clearfield, A. ,Wang, Z.J. Chem. Soc. Dalton
Trans. 2002, 2937; (b) Yang, C.Y. Ph.D. Dissertation, Texas A&M
Univ., Dec 1986.(c) Clearfield, A. Chem. Mater., 1998, 10,
2801.(d) Poojary, D.M.; Zhang, B.; Clearfield, A., J. Am. Chem. Soc.
1997, 119, 12550. (e) Arnold, D.I., Ouyang, X.; Clearfield, A.; Chem.
Mater. 2002, 14, 2020.
6Ortiz-Avila, C. Y.; Bhardwaj, C.; Clearfield, A.
Inorg. Chem. 1994, 33, 2499.