Novel Coordination Polymer of Cadmium (II) with L-Tryptophan

Agnieszka Czylkowska,Anna Pietrzak,Bartłomiej Rogalewicz,Małgorzata Szczesio,Anita Raducka

doi:10.3390/ma13102266

Abstract

A new cadmium (II) polymeric coordination compound with tryptophan (Trp) of general formula {[Cd(L-Trp)2(H2O)Cl]∙(Trp)∙(H2O)}n was synthesized. The monocrystals of the investigated complex were obtained using the method of slow evaporation. The crystal and molecular structure was determined. The compound was crystallized in the orthorhombic P212121 space group. The cadmium atom was seven coordinates by two oxygen atoms from one bidentate-chelating carboxylate group of bridging Trp, two oxygen atoms from one bidentate-chelating carboxylate group from a monodentate organic ligand, one oxygen atom of water molecule, one nitrogen atom of the amino group from bridging Trp and one chlorine atom, which means that every tridentate Trp substituent was bridging towards one cadmium atom and bidentate chelating towards one another. The monodentate Trp is a zwitterionic molecule. The coordination led to the formation of 1D supramolecular chains entrapping water and Trp molecules.

Highlights

Tryptophan (Trp) is an α-amino acid which is very interesting because of its structure
Two tryptophan molecules and a water molecule existed in the inner coordination sphere of the complex
One tryptophan molecule and one water molecule were not bonded with metal ion

Summary

Introduction

Tryptophan (Trp) is an α-amino acid which is very interesting because of its structure. The human body is not able to synthesize it, so it should be supplied from external sources This organic ligand has many applications e.g., in medicine as a drug, in the development of plant tissues, in nanocomposites or as potentiometric pH sensors [1,2,3,4,5]. Tryptophan links with a metal ion using both an indole and a carboxylic group creating coordination polymers [8,9,10,11,12,13] These types of compounds are widely studied due to the possibility of their use. The formation of polymeric structures occurs due to the bridging carboxylate group

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Conclusion