Laser Raman and IR spectra of complexes of lanthanide (III) with 5- aminouracil

Content Provider	Semantic Scholar
Author	Rastogi, V. K. Palafox, Mauricio A. Kumar, V. Sampath Mital, H. P. Sharma, Rekha
Copyright Year	2004
Abstract	Lanthanide (III ) ion complexes with organic ligands can be used as luminescent materials and luminescent labels in fluoroimmunoassays due to their unique luminescence properties such as long luminescence decay time and narrow emission bands [1,2]. Recently, FTIR and FT Raman studies of the series of six coordinated complexes of LnCl3(PyNO)3, where Ln = Pr, Nd, Sm, Eu, Gd, Dy and PyNO = 3-Br-4-CH3OC7H7NO) have been reported [2]. In the present work, we describe the IR and Raman spectra of complexes of Ln (Ln = Pr, Nd, Sm, Gd, and Dy) with 5aminouracil (5-AU). The complex was synthesised by the method given in literature [3]. FTIR and Raman spectra of the ligand (5-AU) and complexes in solid phase have been recorded by KBr pellet technique on Perkin-Elmer Model 1710 in the region 400-4000 cm and Jasco K-500 Raman spectrophotometer in the region 50-4000 cm respectively. The other experimental details are given elsewhere [3]. The complexes formed possess 1:3 stoichiometry and the chemical analyses correspond to the molecular formula [Ln(C4H5N3O2)3]Cl3. The complexes are insoluble in common organic solvents and do not melt upto 330 C. The vibrational spectra of 5-AU have been analysed by assuming planar geometry and Cs point group symmetry and the assignments of fundamental frequencies are made on the basis of magnitude and relative intensities of the observed bands and help has been taken from the assignments made by the earlier workers in the similar molecules [3], and as well theoretically predicted spectra of 5-AU [4]. In the case of 5-aminouracil, Rastogi and Palafox [4] have assigned the bands at 3398 cm (scaled value) to asymmetric and symmetric stretching modes of NH2 group respectively.In the region 3700-3300 cm, as we observe only two bands ,therefore, the higher wavenumber band which is strong in IR spectrum (3370 cm) and weak in Raman spectrum (3380 cm) has been assigned to asymmetric stretch amino group vibration.The symmetric stretch amino mode has been identified at 3300 cm in conformationm with the assignment proposed by other workers in the case of related molecules . In the case of 5-AU , Rastogi and Palafox [4] have shown that the scaled value 1586 cmat B3LYP/ 6-311++G(2d,p) level corresponds to this mode. Therefore, we assign the band at 1588 cm 1 to NH2 scissoring mode. The rocking mode , ρ(NH2) was computed at 1098 cm (scaled value 1082 cm) in the case of 5aminouracil [4] . Therefore, in conformity with this, the IR band observed at 1108 cm has been identified as ρ(NH2) mode. In the case of 5-AU ,wagging NH2 mode is calculated at 705 cm by B3LYP/ 6-311++ G(2d,p) level . However , in this range was not observed experimental band , and the nearest one appears at 749 cm , therefore , we correlate the band with NH2 wagging mode .
Starting Page	150
Ending Page	151
Page Count	2
File Format	PDF HTM / HTML
DOI	10.1071/sa0402060
Alternate Webpage(s)	http://www.publish.csiro.au/SA/pdf/SA0402060
Alternate Webpage(s)	https://doi.org/10.1071/sa0402060
Volume Number	2
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article