Presentation Title

Synthesis and Spectroscopic Characterization of Chromium Acetylacetonato Complexes

Faculty Mentor

John Kenney

Start Date

17-11-2018 10:00 AM

End Date

17-11-2018 10:15 AM

Location

C327

Session

Oral 2

Type of Presentation

Oral Talk

Subject Area

physical_mathematical_sciences

Abstract

Multiple syntheses were carried out to prepare a series a chromium(III) transition metal complexes formally named tris-(acetylacetonato)chromium(III). Literature procedures were refined and corrected for the syntheses of each of these complexes. Through the process of recrystallization, well-defined crystal structures were collected for Cr(acac)3, Cr(acac-Cln)3, and Cr(acac-Brn)3 where acac = acetylacetonato, Cl = chlorine, and Br = bromine. UV-visible and cryogenic luminescence spectra at 77 K were measured for each of these complexes. UV-visible spectral analysis confirmed the identity of Cr(acac)3, Cr(acac-Cln), and Cr(acac-Brn), and luminescence allowed for quantitative determinations of the 0-0 transition energy and fundamental frequency of the breathing vibrations, which do not currently appear in the scientific literature. Bimetallic chromium(III) complexes were synthesized to have hydroxy and methoxy bridging ligands to connect the two chromium(III) metals.

Summary of research results to be presented

The syntheses of Cr(acac)3 resulted in a yield 7.80 g. The chlorination of this complex resulted in .2411 g and a percent yield of 47.92% while the bromination resulted in 1.4846 g (Figure 16) and a percent yield of 74.152%. The dimerization in water resulted in a yield of .0123 g while the dimerization in methanol resulted in a yield of .0818 g (Figure 18). There was no product collected at the end of the attempted dimerization in ethanol. The spectra of Cr(acac)3, the chlorinated monomer, and the brominated monomer are shown in Figures 18, 19, and 20 respectively. The significant peaks for Cr(acac)3 are 779.6, 794.9, 814.3, 822.6, and 843.4 nm. The significant peaks for Cr(acac-Cln)3 are 799.7, 818.4, 835.1, 849.7, and 867.0 nm. The significant peaks for Cr(acac-Brn)3 are 799.0, 808.7. 826.7, 837.8, and 858.0 nm.

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Nov 17th, 10:00 AM Nov 17th, 10:15 AM

Synthesis and Spectroscopic Characterization of Chromium Acetylacetonato Complexes

C327

Multiple syntheses were carried out to prepare a series a chromium(III) transition metal complexes formally named tris-(acetylacetonato)chromium(III). Literature procedures were refined and corrected for the syntheses of each of these complexes. Through the process of recrystallization, well-defined crystal structures were collected for Cr(acac)3, Cr(acac-Cln)3, and Cr(acac-Brn)3 where acac = acetylacetonato, Cl = chlorine, and Br = bromine. UV-visible and cryogenic luminescence spectra at 77 K were measured for each of these complexes. UV-visible spectral analysis confirmed the identity of Cr(acac)3, Cr(acac-Cln), and Cr(acac-Brn), and luminescence allowed for quantitative determinations of the 0-0 transition energy and fundamental frequency of the breathing vibrations, which do not currently appear in the scientific literature. Bimetallic chromium(III) complexes were synthesized to have hydroxy and methoxy bridging ligands to connect the two chromium(III) metals.