Rotational transitions for the symmetric-top transition metal complex C5H5Nb(CO)4 were measured using a Flygare-Balle- type pulsed-beam microwave spectrometer. The spectrum indicates that in the gas phase, this complex is a prolate symmetric top with B = C = 558.842(4) MHz. Transitions were measured in the range 4-12 GHz. The observed splittings due to 93Nb quadrupole coupling were smaller than expected, with eq Q(93Nb) =-1.8(6) MHz. The value DJ = 0.04(2) kHz. No evidence for fluxional behavior was observed. The A rotational constant, calculated from the X-ray data, is A = 670(30) MHz and calculated B and C constants are in agreement with the present microwave values. This appears to be the first measurement of a microwave spectrum and gas-phase quadrupole coupling for a 93Nb organometallic complex.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry