Synthesis and Crystal Structure of N-(2-Pyridylmethyl)-L-Alanine) Isothiocyanate Cobalt(III)

Sally-Judith E Ntum,Aminou Mohamadou,Asseng M Conde,Peter T Ndifon,Linda D Nyamen,Awawou G Paboudam,James Raftery

doi:10.4236/csta.2017.63004

Abstract

The title compound, [N-(2-pyridylmethyl)-(L)-alanine]Co(III) thiocyanate (1) was obtained from the reaction of Co(OOCH3)2·H2O with the tridentate reduced Schiff base ligand, N-(2-pyridylmethyl)-(L)-alanine (L) and NH4SCN and characterized by elemental analysis, IR, UV-visible, TGA and single- crystal X-ray diffraction. Structural and spectroscopic analyses reveal [Co(L)2)]SCN to be monomeric with Cobalt(III) adopting a pseudo-octahedral geometry, coordinating to two reduce Schiff base ligands. In the crystal lattice, the thiocyanate anion forms an intermolecular SCN···HNamine hydrogen bond, while adjacent monomers are linked by intermolecular Ocarboxyl···HNamine···H-bonds to form a supramolecular network. This work is therefore undertaken in an attempt to construct coordination framework structures of varying properties using the mixed-ligand strategy involving reduced Schiff bases and the thiocyanate ion.

Highlights

Cobalt complexes of Schiff base ligands are an important class of coordination compounds due to their structural diversity which display geometries ranging from tetrahedral, bipyramidal, square pyramidal to octahedral [1] [2] [3]
The thiocyanate anion forms an intermolecular SCN∙∙∙HNamine hydrogen bond, while adjacent monomers are linked by intermolecular Ocarboxyl∙∙∙HNamine∙∙∙H-bonds to form a supramolecular network
This work is undertaken in an attempt to construct coordination framework structures of varying properties using the mixed-ligand strategy involving reduced Schiff bases and the thiocyanate ion

Summary

Introduction

Cobalt complexes of Schiff base ligands are an important class of coordination compounds due to their structural diversity which display geometries ranging from tetrahedral, bipyramidal, square pyramidal to octahedral [1] [2] [3]. Reduced Schiff base ligands have been found to be relatively inert towards air oxidation and are strongly coordinating due to the reduction of the N=C bond, giving rise to flexible multidentate ligands [8] [9]. The thiocyanate ions have been found to possess versatile coordination abilities which result in the formation of metal complexes of varied structures. Thiocyanate-containing metal complexes have attracted much attention due to their versatile binding modes and its propensity to coordinate using either the nitrogen or/and the sulphur donor-atom, affording a number of homo- and hetero-metallic discrete structural assemblies with specific structural features and properties [10]. The crystal structure of one such compound is reported here

Physical Measurements

Synthesis and Crystallization

Results and Discussion

Conclusion