MEASUREMENTS OF STRUCTURAL AND QUADRUPOLAR COUPLING PARAMETERS FOR CHLOROFERROCENE USING MICROWAVE SPECTROSCOPY

Rotational spectra for two isotopomers of chloroferrocene were measure d using pulsed-beam Fourier transform microwave spectroscopy. Transiti ons were observed for Cl-35 and Cl-37 isotopomers in the 4-10 GHz rang e. Chlorine quadrupole coupling strengths and rotational constants wer e obtained from the data. The rotational constants and quadrupole coup ling strengths for Cl-35 are A = 1370.009(8) MHz, B = 767.342(1) MHz, C = 634.8834(6) MHz, eQq(aa) = -9.06(4) MHz, and eQq(bb) = -28.43(6) M Hz and for Cl-37 are A = 1362.23(2) MHz, B = 751.623(2) MHz, C = 622.3 24(1) MHz, eQq(aa) = -8.78(18) MHz, and eQq(bb) = -20.76(9) MHz. These measured rotational constants were used to determine the following st ructural parameters of chloroferrocen: r(Fe-(C5H5)) = 1.594(20) Angstr om, r(Fe-(C5H4Cl)) = 1.699(13) Angstrom, r(C-Cl) = 1.7204(9) Angstrom, and r(C-C) = 1.4329(7) Angstrom. No evidence for internal rotation wa s observed in the microwave spectrum.