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Title: Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts

Abstract

Resonance Raman spectra with variable-wavelength excitation are reported for Ni{sup II} porphine (NiP) and for the pyrrole-d{sub 8}, meso-d{sub 4}, and (pyrrole + meso)-d{sub 12} isotopomers, as well as for Ni{sup II} meso-tetraphenylporphine (NiTPP) and its pyrrole-{sup 15}N{sub 4}, pyrrole-d{sub 8}, {sup 13}C{sub 4}-meso, and phenyl-d{sub 20} isotopomers. All the Raman-active in-plane modes have been identified and are assigned to local coordinates which take into account the phasing of adjacent bond stretches within the pyrrole rings and at the methine bridges. The IR spectra of NiP and its isotopomers are also assigned. For most of the local coordinates good frequency agreement is seen for the different symmetry blocks, showing that longer range phasings have minor effects. These in-plane mode assignments are supported by normal-coordinate calculations with a physically reasonable valence force field, which is nearly the same for NiP and NiTPP. The principal force constants are in good accord with bond length relationships selected on the basis of scaled ab initio calculations. The phenyl substituents of NiTPP lower the frequencies of the asymmetric methine bridge stretching modes {nu}{sub 10}(B{sub 1g}) and {nu}{sub 19}(A{sub 2g}) by {approximately}60 cm{sup {minus}1}; this shift is attributable partly to the loss of coupling with themore » C{sub m}H bending modes in NiP and partly to an electronic effect of the phenyl group. There are also near-resonant interactions in NiTPP between porphyrin and phenyl modes near 740 and 200 cm{sup {minus}1} resulting in strongly displaced modes. Otherwise the phenyl groups have little influence on the porphyrin skeletal mode frequencies. Several phenyl modes are subject to moderate RR enhancement, probably via intensity borrowing from nearby porphyrin modes.« less

Authors:
; ; ;  [1];  [2]
  1. Princeton Univ., NJ (USA)
  2. Marquette Univ., Milwaukee, WI (USA)
Publication Date:
OSTI Identifier:
6711700
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry; (USA)
Additional Journal Information:
Journal Volume: 94:1; Journal ID: ISSN 0022-3654
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 59 BASIC BIOLOGICAL SCIENCES; PORPHYRINS; INFRARED SPECTRA; RAMAN SPECTRA; DATA ANALYSIS; ENERGY LEVELS; EXPERIMENTAL DATA; ISOTOPE EFFECTS; MEASURING INSTRUMENTS; MEASURING METHODS; NICKEL; VALENCE; CARBOXYLIC ACIDS; DATA; ELEMENTS; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; INFORMATION; METALS; NUMERICAL DATA; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; SPECTRA; TRANSITION ELEMENTS; 400202* - Isotope Effects, Isotope Exchange, & Isotope Separation; 550200 - Biochemistry

Citation Formats

Li, Xiaoyuan, Czernuszewicz, R S, Su, Y O, Spiro, T G, and Kincaid, J R. Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts. United States: N. p., 1990. Web. doi:10.1021/j100364a007.
Li, Xiaoyuan, Czernuszewicz, R S, Su, Y O, Spiro, T G, & Kincaid, J R. Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts. United States. https://doi.org/10.1021/j100364a007
Li, Xiaoyuan, Czernuszewicz, R S, Su, Y O, Spiro, T G, and Kincaid, J R. 1990. "Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts". United States. https://doi.org/10.1021/j100364a007.
@article{osti_6711700,
title = {Consistent porphyrin force field. 1. Normal-mode analysis for nickel porphine and nickel tetraphenylporphine from resonance Raman and infrared spectra and isotope shifts},
author = {Li, Xiaoyuan and Czernuszewicz, R S and Su, Y O and Spiro, T G and Kincaid, J R},
abstractNote = {Resonance Raman spectra with variable-wavelength excitation are reported for Ni{sup II} porphine (NiP) and for the pyrrole-d{sub 8}, meso-d{sub 4}, and (pyrrole + meso)-d{sub 12} isotopomers, as well as for Ni{sup II} meso-tetraphenylporphine (NiTPP) and its pyrrole-{sup 15}N{sub 4}, pyrrole-d{sub 8}, {sup 13}C{sub 4}-meso, and phenyl-d{sub 20} isotopomers. All the Raman-active in-plane modes have been identified and are assigned to local coordinates which take into account the phasing of adjacent bond stretches within the pyrrole rings and at the methine bridges. The IR spectra of NiP and its isotopomers are also assigned. For most of the local coordinates good frequency agreement is seen for the different symmetry blocks, showing that longer range phasings have minor effects. These in-plane mode assignments are supported by normal-coordinate calculations with a physically reasonable valence force field, which is nearly the same for NiP and NiTPP. The principal force constants are in good accord with bond length relationships selected on the basis of scaled ab initio calculations. The phenyl substituents of NiTPP lower the frequencies of the asymmetric methine bridge stretching modes {nu}{sub 10}(B{sub 1g}) and {nu}{sub 19}(A{sub 2g}) by {approximately}60 cm{sup {minus}1}; this shift is attributable partly to the loss of coupling with the C{sub m}H bending modes in NiP and partly to an electronic effect of the phenyl group. There are also near-resonant interactions in NiTPP between porphyrin and phenyl modes near 740 and 200 cm{sup {minus}1} resulting in strongly displaced modes. Otherwise the phenyl groups have little influence on the porphyrin skeletal mode frequencies. Several phenyl modes are subject to moderate RR enhancement, probably via intensity borrowing from nearby porphyrin modes.},
doi = {10.1021/j100364a007},
url = {https://www.osti.gov/biblio/6711700}, journal = {Journal of Physical Chemistry; (USA)},
issn = {0022-3654},
number = ,
volume = 94:1,
place = {United States},
year = {Thu Jan 11 00:00:00 EST 1990},
month = {Thu Jan 11 00:00:00 EST 1990}
}