Synthesis, Characterization, and Thermal Analysis of Two Polymeric Chromium Ternary Complexes with Nitrilotriacetic Acid and Alanine or Glycine Eman H. Ismail, Eglal R. Souaya, Amr A. Mohamed Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo, Egypt Received 30 November 2010; accepted 12 June 2011 DOI 10.1002/app.35097 Published online 25 October 2011 in Wiley Online Library (wileyonlinelibrary.com). ABSTRACT: Two chromium ternary complexes with nitrilotriacetic acid as a primary ligand and alanine or glycine as secondary ligand were prepared in slightly acidic medium. The structure of these two complexes was characterized using elemental, thermal analysis, FTIR spectra, and the two complexes mass spectra. The spectroscopy data suggest that these two complexes were in polymeric form and have the monomeric unit H[Cr(HNTA)(Hala)(SO 4 )] and H[Cr(HNTA)(Gly)(SO 4 )] in which sulfate group act as a bidentate ligand linked between each monomeric unit for the same com- plex. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: 1976–1980, 2012 Key words: chromium; ternary complex; nitrilotriacetic acid; alanine; glycine INTRODUCTION Polymers of amino acid compounds have found wide application in a number of area such as photo resistance, coatings, and antibodies. 1–4 Besides pos- sessing good thermal properties. These polymers also exhibit variability of electro conductivity due to one free amino group per repeat unit on the poly- mers and potentially wide applicability. 5–13 These compounds have emerged as a new generation materials with tremendous potentials in fields like superconductivity and heat stability material. 14 Chromium, which is an abundant element in the earth crust, has many applications in both industrial and pharmaceutical fields. It is used in industry for plating and in chrome steels, ceramics, catalysis, and many other applications. 15–19 It is also present in many pharmaceutical products due to its ability to stabilize blood sugar level. 20 For these reasons many scientists keep trying to prepare novel compounds that containing chromium, especially coordination compounds. 21–26 Aminocarboxylate chelating agent (Nitrilotriacetic acid, for example) can be considered one of the most important ligands which we can use to prepare a coordination compound. Aminocarboxylate chelates strongly with most metals, this chelation change metal bioavailability and mobility in the environ- ment. 27 These complexes may be used as laundry detergent builders, boiler scale inhibitors, in metal plating and cleaning operation, in textile manufac- ture, and in paper and cellulose production. 28,29 Amino acid is one of the most important biologi- cal substances, therefore, the study of ternary com- plexes which containing amino acid as a secondary ligand was and is still one of the most interesting points of research because it reveals the role of the metal ion on the molecular level. 30–33 In this work, preparation and characterization of new chromium ternary complexes with nitrilotriace- tic acid glycine or alanine as secondary ligand are studied. EXPERIMENTAL General procedure for complexes preparation Two solutions were prepared, the first contains 10 3 mole of the Cr 2 (SO 4 ) 3 15 H 2 O salt in 100 mL water and the second one containing a mixture of 10 3 mole of nitrilotriacetic acid and 10 3 mole of alanine (complex I) or glycine (complex II) in 100 mL water. The two solutions were mixed and heated nearly to boiling to ensure complete reaction. The solution was left on a water bath until the volume was reduced to about 50 mL. The solid complexes were obtained after heating by adding 96% ethanol, and then the solid complexes filtered off and washed several times with ethanol following by 1 mL of diethyl ether. The prepared complexes were kept in vacuum desiccator under silica gel. Correspondence to: E. H. Ismail (dr_science_7@hotmail. com). Journal of Applied Polymer Science, Vol. 124, 1976–1980 (2012) V C 2011 Wiley Periodicals, Inc.