Some metal complexes of dihydroxycyclobutenedione

"This study involves an investigation of some of the physical and chemical properties of the trivalent metal squarate complexes of iron, vanadium, and indium in order to determine their structure. In this investigation studies were made of the infrared spectra, electronic spectra, x-ray diffraction powder photographs and diffractometer patterns, magnetic susceptibilities, and thermogravimetric patterns for the trihydrate, dihydrate, and anhydrous squarate complexes of vanadium(III) and iron (III) and the dihydrate squarate complex of indium(III). These studies suggest that the structures of the vanadium(III) and iron(III) squarate complexes are dimeric with hydroxyl bridges between the metal atoms. This is supported by the presence of a band between 980 and 1050 cm⁻1 in the infrared spectrum associated with metal-hydroxyl bridging. Crystal field calculations made from data obtained from the electronic spectra of the vanadium(III) squarate trihydrate and vanadium(III) squarate dihydrate suggest that the vanadium atoms are in an approximately cubic crystal field, Racah parameter B = 611 and 655 cm⁻¹ respectively and crystal field splitting l0Dq = 18,900 and 19,650 cm⁻¹ respectively. The x-ray diffraction studies indicate that the vanadium(III) squarate trihydrate and iron(III) squarate trihydrate are isostructural. The magnetic moments of approximately 2.80 B.M. for the trihydrate and dihydrate vanadium(III) squarate complexes are normal for a paramagnetic d² metal complex. However, the magnetic moment of 2.60 B.M. for the anhydrous vanadium(III) squarate complex suggest some spin coupling between metal atoms. The reduced magnetic moment of 5.08 B.M. at room temperature for iron(III) squarate dihydrate, 5.9 B.M. is normal for a d⁵ metal complex, and the temperature dependence study of the magnetic susceptibility indicate that the complex is a binuclear antiferromagnetic system with S = 5/2 and J = -6.8. The reduced moment of 4.6 B .M. and the temperature dependence study of the magnetic susceptibility of anhydrous iron (III) squarate suggest that it is an antiferromagnetic system with the spin-spin exchange taking place between more than two metal atoms. The data collected for indium(III) squarate dihydrate were inconclusive i:n determining its structure"--Abstract, pages ii-iii.

Name thesis:degree_name

Ph. D. in Chemistry

Grantor

University of Missouri--Rolla

Year dc:date.available

2016

Author dc:creator

• Condren, Stewart Michael

• Chemistry

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2053

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3055