Microwave spectra, ab initio and DFT calculations and molecular structure for (η7-cycloheptatriene)Ti(η5-cyclopentadienyl) and (η7-cycloheptatriene)Cr(η5-cyclopentadienyl)

Adam M. Daly, Catherine M. Lavin, Erika S. Weidenschilling, Alison M. Holden, Stephen G. Kukolich

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Microwave spectra of 1-d-(η7-cycloheptatriene) 48Ti(η5-cyclopentadienyl) (CHT-Ti-Cp) and two singly substituted 13C isotopomers were measured and gas phase structural parameters were determined. Rotational transitions were also measured for (η7-cycloheptatriene)52Cr(η5- cyclopentadienyl). Rotational constants for the Ti complex were found to be A = 1720(4) MHz, B = 769.269(1) MHz and C = 766.131(1) MHz and for [ 13CC6H7-48Ti-C5H 5], A = 1773(2) MHz, B = 769.6931(4) MHz and C = 761.1789(5) MHz and for [1-d-C7H648TiC5H5] and A = 1270(5) MHz, B = 767.0142(9) MHz and C = 765.323(1) MHz for [C 7H748Ti13CC4H 5]. A structural analysis for the (CHT-Ti-Cp) data showed that the cycloheptatriene ring protons droop towards titanium as predicted by DFT and MP2 calculations. The droop of the protons toward the metal was experimentally determined to be 8.0(2)°out of the plane of the cycloheptatriene ring. The ring center distance to titanium was found to be 2.01(3) for Ti-Cp and 1.48(3) for Ti-CHT using a least squares fit to the measured rotational constants and fixing many of the structural parameters to the calculated values. The spectrum of the normal isotopomer (η7-cycloheptatriene) Ti(η5-cyclopentadienyl) was re-measured and a discussion of the possible 47Ti quadrupole coupling constants is presented. The chromium analog K = 0 spectrum was analyzed to obtain B = 851.229 MHz, and DJ = 0.028(6) kHz. Results from structure calculations are reported and discussed for (CHT-M-Cp) complexes with M = Ti, Cr, Zr, Hf, Mo, W using MP2, B3PW91 and B3LYP methods.

Original languageEnglish (US)
Pages (from-to)172-177
Number of pages6
JournalJournal of Molecular Spectroscopy
Volume267
Issue number1-2
DOIs
StatePublished - May 1 2011

Keywords

  • Microwave
  • Organometallic complex
  • Structure measurements

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Spectroscopy
  • Physical and Theoretical Chemistry

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