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Title: Vibrational characterization of multiply metal-metal bonded osmium, molybdenum, and rhenium porphyrin dimers

Abstract

The resonance Raman (RR) scattering and infrared (IR) absorption spectra of ((M(OEP)){sub 2}){sup n+} complexes (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin dianion; M = Os (n = 0-2), Re (n = 0-2), and Mo (n=0)) are reported. Resonance Raman studies reveal the Os-Os stretch to increase in frequency upon oxidation (233 cm{sup {minus}1} (n = 0), 254 cm{sup {minus}1} (n = 1), and 266 cm{sup {minus}1} (n = 2)), consistent with the removal of electrons from {pi}* metal-metal antibonding orbitals. The Mo-Mo stretch was also observed spectroscopically, producing a RR peak at 341 cm{sup {minus}1}, while the Re-Re stretch in ((Re(OEP)){sub 2}){sup 1+} was observed at 290 cm{sup {minus}1}. The corresponding metal-metal bond distances estimated from these stretching frequencies are 2.39, 2.31, and 2.27 {angstrom} for the osmium oxidation series, 2.23 {angstrom} for the molybdenum dimer, and 2.20 {angstrom} for the rhenium dimer. The porphyrin-centered vibrational modes (both RR and IR active) for the three osmium complexes are essentially independent of oxidation state, consistent with oxidation of metal-metal antibonding electrons. Little {pi} back-bonding between the metal and porphyrin macrocycle is suggested from porphyrin RR indicator modes, which are sensitive to {pi} electron density. Moreover, the porphyrin core size (center to nitrogen distance) ismore » estimated from core size marker vibrations to be ca. 2.04 {angstrom} for all of the complexes studied. Finally, no vibrational evidence for ground-state intradimer coupling between the {pi} orbitals of the porphyrin rings is found.« less

Authors:
; ;  [1]; ;  [2]
  1. Los Alamos National Lab., NM (USA)
  2. Stanford Univ., CA (USA)
Publication Date:
OSTI Identifier:
7157110
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society; (USA)
Additional Journal Information:
Journal Volume: 111:25; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; PORPHYRINS; VIBRATIONAL STATES; DATA ANALYSIS; DIMERS; EXPERIMENTAL DATA; INFRARED SPECTRA; MEASURING INSTRUMENTS; MEASURING METHODS; MOLYBDENUM; OSMIUM; RAMAN SPECTRA; RHENIUM; CARBOXYLIC ACIDS; DATA; ELEMENTS; ENERGY LEVELS; EXCITED STATES; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; INFORMATION; METALS; NUMERICAL DATA; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PLATINUM METALS; SPECTRA; TRANSITION ELEMENTS; 400000* - Chemistry; 400201 - Chemical & Physicochemical Properties; 400500 - Photochemistry; 360104 - Metals & Alloys- Physical Properties

Citation Formats

Tait, C D, Sattelberger, A P, Woodruff, W H, Garner, J M, and Collman, J P. Vibrational characterization of multiply metal-metal bonded osmium, molybdenum, and rhenium porphyrin dimers. United States: N. p., 1989. Web. doi:10.1021/ja00207a012.
Tait, C D, Sattelberger, A P, Woodruff, W H, Garner, J M, & Collman, J P. Vibrational characterization of multiply metal-metal bonded osmium, molybdenum, and rhenium porphyrin dimers. United States. https://doi.org/10.1021/ja00207a012
Tait, C D, Sattelberger, A P, Woodruff, W H, Garner, J M, and Collman, J P. Wed . "Vibrational characterization of multiply metal-metal bonded osmium, molybdenum, and rhenium porphyrin dimers". United States. https://doi.org/10.1021/ja00207a012.
@article{osti_7157110,
title = {Vibrational characterization of multiply metal-metal bonded osmium, molybdenum, and rhenium porphyrin dimers},
author = {Tait, C D and Sattelberger, A P and Woodruff, W H and Garner, J M and Collman, J P},
abstractNote = {The resonance Raman (RR) scattering and infrared (IR) absorption spectra of ((M(OEP)){sub 2}){sup n+} complexes (OEP = 2,3,7,8,12,13,17,18-octaethylporphyrin dianion; M = Os (n = 0-2), Re (n = 0-2), and Mo (n=0)) are reported. Resonance Raman studies reveal the Os-Os stretch to increase in frequency upon oxidation (233 cm{sup {minus}1} (n = 0), 254 cm{sup {minus}1} (n = 1), and 266 cm{sup {minus}1} (n = 2)), consistent with the removal of electrons from {pi}* metal-metal antibonding orbitals. The Mo-Mo stretch was also observed spectroscopically, producing a RR peak at 341 cm{sup {minus}1}, while the Re-Re stretch in ((Re(OEP)){sub 2}){sup 1+} was observed at 290 cm{sup {minus}1}. The corresponding metal-metal bond distances estimated from these stretching frequencies are 2.39, 2.31, and 2.27 {angstrom} for the osmium oxidation series, 2.23 {angstrom} for the molybdenum dimer, and 2.20 {angstrom} for the rhenium dimer. The porphyrin-centered vibrational modes (both RR and IR active) for the three osmium complexes are essentially independent of oxidation state, consistent with oxidation of metal-metal antibonding electrons. Little {pi} back-bonding between the metal and porphyrin macrocycle is suggested from porphyrin RR indicator modes, which are sensitive to {pi} electron density. Moreover, the porphyrin core size (center to nitrogen distance) is estimated from core size marker vibrations to be ca. 2.04 {angstrom} for all of the complexes studied. Finally, no vibrational evidence for ground-state intradimer coupling between the {pi} orbitals of the porphyrin rings is found.},
doi = {10.1021/ja00207a012},
url = {https://www.osti.gov/biblio/7157110}, journal = {Journal of the American Chemical Society; (USA)},
issn = {0002-7863},
number = ,
volume = 111:25,
place = {United States},
year = {1989},
month = {12}
}