Download Raman and SERS investigation of new synthesized nicotinic acid

RAMAN AND SERS INVESTIGATION OF NEW SYNTHESIZED NICOTINIC
ACID METALLIC COMPLEXES
T. Jurca1, S. Cavalu1, S.Cîntă Pînzaru2
1
University of Oradea, Faculty of Medicine and Pharmacy,
Nicolea Jiga 29 , Oradea Romania
2
Babes Bolyai University, Molecular Spectroscopy Dept.,
Kogălniceanu 1, RO 400084 Cluj-Napoca, Romania
An important direction in the coordination chemistry of pharmaceutical compounds is
the development of the synthesis regarding the complexes containing biologically active
metals and physiologically active organic ligands, where coordination-bound metals possess
significantly higher efficiency and low toxicity.
Nicotinic acid or niacin, a water-soluble B complex vitamin and antihyperlipidemic
agent, is 3-pyridincarboxylic acid (C6H5NO2) and play an important role in the biochemical
redox processes.
The functional group of nicotinic acid is capable to form different complexes with
trace metals. Nicotinic acid and their complexes combination with copper, cobalt and
cadmium acetate (Ac) were characterized using Raman spectroscopy.
SERS spectrum of the nicotinic acid was recorded in order to draw conclusions concerning
the adsorption behaviour of the ligand to a metal surface versus metal coordination to a metal
complex. SERS results revealed a chemisorption of the ligand species through the N ring
atom with respect to the metal surface. The spectral data of the complexes suggested a
bidentate coordination with the proposed structure given in the Fig. 1. The differences
between the chemisorbed oriented geometry and the coordinated ligand are discussed.
OH
Ac
N
C=O
O=C
Me
N
Ac
HO
Fig. 1. Schematic molecular structure of the metal-nicotinic acid complexes.
References
[1] S. Cîntă Pînzaru, I.Pavel, N. Leopold, W. Kiefer, J. Raman Spectrosc., 335: 338-346, 2004.
[2] T. Iliescu, S.Cîntă, S. Astilean, I. Bratu, J. Mol. Struct. , 193, 410-411, 1997.
[3] S. Cîntă, M.Venter, T. Iliescu, O. Cozar, I.Haiduc, W. Kiefer, Vibr. Spectrosc., 19, 223-226, 1999.
[4] T. Jurca, S. Cavalu, S.Cîntă, V. Simon, Studia Physica, UBB, XLIV 1, 457-460, 2003.