The Microwave Spectrum of Cyclopentadienyl Niobium Tetracarbonyl

✍ Scribed by J.C. Earp; D.S. Margolis; C. Tanjaroon; T.E. Bitterwolf; S.G. Kukolich

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 71 KB
• Volume: 211
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8466

✦ Synopsis

Rotational transitions for the symmetric-top transition metal complex C 5 H 5 Nb(CO) 4 were measured using a Flygare-Balletype 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 93 Nb quadrupole coupling were smaller than expected, with eq Q( 93 Nb) = -1.8(6) MHz. The value D J = 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 93 Nb organometallic complex.