Structural and Electronic Studies of Substituted m-Terphenyl Group 12 Complexes.

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Two-coordinate Group 12 metal complexes with m-terphenyl ligands are synthesized.
• Para-substitution on the terphenyl backbone is explored to tune properties.

Purpose of the Study:

• Investigate the effect of para-substitution on structural and electronic properties of Group 12 complexes.
• Correlate substituent electronic effects with NMR spectroscopic data.
• Rationalize observed trends using computational methods.

Main Methods:

• Synthesis of four series of Group 12 complexes (Zn, Cd, Hg) with varying para-substituents (t-Bu, SiMe3, Cl, CF3).
• X-ray crystallography to determine structural parameters.
• Heteronuclear NMR spectroscopy (113Cd, 199Hg, 1H) to probe electronic properties.
• Density Functional Theory (DFT) calculations for theoretical analysis.

Main Results:

• X-ray crystallography revealed minimal structural variations across the series.
• NMR spectroscopy showed significant electronic differences correlated with para-substituents.
• A linear correlation was found between NMR chemical shifts and Hammett constants.
• Electron-withdrawing substituents induced an upfield shift in NMR signals.

Conclusions:

• Para-substitution on m-terphenyl ligands effectively modulates the electronic properties of Group 12 metal complexes.
• NMR spectroscopy serves as a sensitive probe for these electronic changes.
• DFT calculations can help explain the observed structure-property relationships.