Vanadyl Porphine Phenyl Substituted

Vanadyl naphthalocyanine and Vanadyl Porphine Phenyl Substituted 

The bands at 1,509 and 1,365cm in VOTPNPc and at 1,421 and 1,337 cm in VOTPPORP were ascribed to pyrrole fragment modes. The VO stretching modes were assigned to the bands at 944 and 919 cm in VOTPNPc and at 968 and 922 cm in VOTPPORP. The assignment of this mode is particularly important as the vanadyl group may be involved in an eventual substrate-adsorbate interaction. The macrocycle deformations at 527 and 507 cm in the spectrum of VOTPPORP involve the VO group. 

Some bands are observed only in one of the two tetraphenyl substituted complexes this is the case for the band at 954 cm which is assigned to a breathing mode of the VOTPNPc, the band at 802 cm in VOTPPORP assigned to an out of plane CH mode of the pyrrole ring, the band at 791 cm corresponding to the macrocycle deformation, and the ring porphine bands at 702, 662 and 575 cm  

The resonant effect, which concerns mainly vibrational modes belonging to the coordination site, is manifested by changes in the relative intensity of several bands. The band about 1,600 cm decreases its intensity and the bands around 1,300, 900, 700 and at 340 and 298 cm increase their intensities. Other bands at 1,367, 1,222, 1,006, 839 and 650cm maintain or slightly decrease their relative intensities. The intensity decreasing of the coupled vCC/vCN band at 1,600 cm indicates that this mode is an asymmetric vibration with an important vCC component of the pendant group. The spectral behavior of the bands which increase their intensity indicates that the corresponding modes are symmetric vibrations. 

The vNiN vibrations were assigned in 2,6-diacetylpyridine dioxime at 416, 341 and 276 cm and at 370 and 265 cm in hexaamine complexes, at 410 and 334 cm in triethylendiamine derivatives, around 240 cm in pyridine derivatives and in imidazol complexes between 325 and 210cm Gobemado-Mitre et al attributed the vCuN mode in copper complex of naphthalocya-nine to those bands observed at 341 and 221 cm In Cu(II) tri-azamacrocycles it has been proposed the bands at 383 and 314 cm as due to vCuN. This mode was observed in copper complexes of cyclam at 437 cm and in Cu(II) hexaazacyclophane at 390 and 280 cm In phenantroline Cu(II) complexes the vCuN vibration was identified with the bands at 300 and 430 cm In the case of the Zn complexes, some tetraamine derivatives display the vZnN band at 432cm and in triethylendiamine complexes were observed at 405 and 291 cm in imidazole complexes the vZnN mode was assigned to the bands between 325 and 210 cm The vZnN mode of bis(phenylhydrazine)-l, 10-phenantroline Zn(II) was attributed to the bands at 376 and 267cm  

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Carrasco, EA., M.M. Campos-Vatlette, M. Saavedra, G. Diaz, R.E. Clavijo, J.V. Garcia-Ramos, and S. Sanchez-Cortes (2001). Vanadyl naphthalocyanine and vanadyl porphine phenyl substituted macrocycles SERS and thin film organisation studies. Vib. Spectmsc. 26, 201. 

The SERS spectral data obtained on colloidal Ag as well as Ag island films indicate a weak macrocycle interaction and small structural modifications of the naphthalocyanine complex on the surface. An energy transfer mechanism contribution to the observed enhancement was proposed. The whole spectral data point that the naphthalocyanine complex is oriented with the naphthalocyanine plane face-on to the surface. In both vanadylnaphthalocyanine and vanadylpor-phine tetraphenyl substituted complexes the vanadyl group is perpendicular to the coordination site and opposed to the surface. In both complexes the phenyl substituents, oriented perpendicular to the macrocycle plane, are responsible of the weak adsorbate-substrate interaction. Several different experimental conditions such as scanning speed, laser power and excitation lines wavelengths, concentration and metal surfaces were intended to obtain SERS of the porphine complex without success this was interpreted in terms that the complex has no interaction with the surface. Thus, it was concluded that the extension of the whole r-system plays a significant role in the mechanism involving the spectral enhancement by surface effect. 

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