Vibrational spectra and structure of perchlorinated metal‐free phthalocyanine and lutetium bisphthalocyanine

Abstract

The infrared and Raman spectra of perchlorinated phthalocyanine (Pc), H2PcCI,, , LuPc,CI,, and the unsymmetrical LuPc,CI,, are reported. The vibrational data set also include SERRS and the far-infrared spectra between 100 and 400 cm-'. The vibrational assignment of characteristic wavenumbers was supported by a semiempirical calculation using the PM3 Hamiltonian. The H,Pc molecule was used as a reference in the PM3 vibrational calculations. The effect of the chlorine substituents on the optical spectra of the phthalocyanine ring is examined. I N T R O D U C T I O NIn early work, Kluiev et al.' studied the mid-infrared spectra of chloro derivatives of metallated phthalocyanine (Pc) molecules in KBr pellets. In their work, the C-Cl stretching vibrations in tetrachloro-CuPc were assigned to wavenumbers observed at 632, 698,700, 825 and 835 cm-'. However, the interpretation of vibrational wavenumbers in the perchlorinated molecule was not attempted, but it was asserted that the infrared spectrum of the latter was much simpler than that of the other derivatives. The electronic spectra of Zn, Co and Fe perchlorinated Pc molecules have also been reported., In this paper, the Raman and surfaceenhanced resonant Raman scattering (SERRS) spectra of H2PcCl,, , LuPc,Cl,, and the unsymmetrical LuPc2c116 are reported for the first time. Using infrared and Raman data and with the help of semi-empirical calculations, the observed characteristic vibrational wavenumbers were successfully assigned and the effect of chlorination on the vibrational spectra was examined. EXPERIMENTALChlorinated phthalocyanines (HzPcCl, 6, LuPc,c1,6 and LuPc2C1,,) were kindly supplied by Dr L. Tomilova. Samples were prepared in KBr pellets for Raman and mid-infrared experiments and in Nujol mulls for far-infrared measurements. The materials are insoluble in all common organic solvents, which prevented the fabrication of monomolecular films. Cast films of H,PcCl,, were prepared on Ag films from emulsions in chloroform for reflection-absorption infrared experi-* Author to whom correspondence should be addressed. 0377-0486/93/12~3-M sO8.M) 0 1993 by John Wiley & Sons, Ltd.ments. Similarly, cast films were used to observe SERRS on gold island films., A Spectra-Physics Model 2020 krypton ion laser was used to obtain inelastic scattering, which was measured with a Spex-1403 double spec-. trometer. A Lexel argon ion laser was used to excite the non-resonance spectra measured with a THR-3000 spectrograph equipped with a liquid nitrogen-cooled Spex CCD detector. Infrared spectra were measured on a BOMEM DA3 Fourier transform (FT)IR spectrometer equipped with an MCT detector and a DTGS pyroelectric detector operating at 300 K. A beamsplitter consisting of a 6 pm stretched Mylar pellicle was used for the far-infrared measurements. For data analysis, all files were imported to Spectra Calc software available from Galactic Industries. CalculationsSemi-empirical methods provide useful complementary information in the assignment of vibrational wavenumbers in large mole...

Structural and Electrochemical Properties of Lutetium Bis-Octachloro-Phthalocyaninate Nanostructured Films. Application as Voltammetric Sensors

“…38 A similar profile is also observed comparing the spectra in Figures 4(a) and (c), i.e., the FTIR spectra for LS and LB films in transmission mode, indicating that both LS and LB present the LuPc 2 Cl 32 structured in a similar way. Besides, all spectra are similar to that observed to LuPc 2 Cl 32 in KBr pellet given by Gobernado-Mitre et al 36 Therefore, because the FTIR spectrum of the powder is characteristic of randomly structured system, it can be concluded that, despite LB and LS grow in a well stratified and packed layers, they present a non-preferential molecular arrangement.…”

“…Table I shows a list of vibrational modes and their assignment for LB and LS films. 36 An important point to be noticed here is that according to the surface selection rules 37 the fundamental vibrations with dynamic dipole parallel to the substrate surface have maximum intensity for the FTIR spectra obtained in transmission mode (incident electric field parallel to the substrate surface). In reflection mode (incident electric field polarized perpendicularly to the substrate surface), the intensities of the fundamental vibrations with dynamic dipole perpendicular to the substrate surface have maximum intensity.…”

Influence of Iodine Doping on the Structure, Morphology, and Physical Properties of Manganese Phthalocyanine Thin Films

“…Macrocycle deformation and isoindole ring deformations exhibit Raman shift in the range of 200–500 cm –1 . Peaks appearing in the frequency ranges of 500–1000 cm –1 correspond to benzene ring deformation and the macrocycle breathing (expansion and contraction) , of MnPc molecules. Regions from 1100 to 1300 arise because of the C–H bending and pyrrole ring stretching.…”

“…Raman spectra of 50 nm thick MnPc and I-MnPc films on silicon substrate obtained with 532 nm laser (a) spectra in the region 100-1700 cm -1 , (b) and (c) show the expanded regions of interest for I-MnPc film.10Macrocycle deformation and isoindole ring deformations exhibit Raman shift in the range of 200-500 cm -1 . Peaks appearing in the frequency ranges of 500-1000 cm -1 correspond to benzene ring deformation and the macrocycle breathing (expansion and contraction)33,34 of MnPc molecules. Regions from 1100 to arise due to the C-H bending and pyrrole ring stretching.…”

Conversion of ethanol to acetone & other produces using nano-sensor SnO<sub>2</sub>(110): Ab initio DFT

“…The heat of formation is calculated for these methods by subtracting atomic heats of formation from the binding energy. MNDO has been used widely to calculate heats of formation, molecular geometries, dipole moments, ionization energies, electron affinities, and other properties [11,12]. MNDO gives better results for some classes of molecule, such as some phosphorus compounds.…”