Designing Ge-N Donor Acceptor Complexes That Change Structure in Solid-State or in Solution

Keisha Kappel, Jim Phillips, Department of Chemistry, University of Wisconsin-Eau Claire, 105 Garfield Road, Eau Claire WI 54701

The primary goal of this project is to design donor-acceptor complexes with intermediate strength and potential to change structure between gas-phase and solid-state or solution. In this specific instance, we are exploring complexes with an overall geometry that places connecting bonds on opposite sides of a 5-corrdinate metal, in the axial orientation, which is a desirable orientation for possible nanotechnology applications stemming from these structures. Accordingly, we conducted surveys for series of structures with quantum-chemical computations. (i.e., these are computer simulations of electron distribution and bonding, specifically based on the methods M06-2X, M06, and ω-B97X-D with the aug-cc-pVTZ basis set). From these we determine equilibrium geometries, vibrational frequencies, and Ge-N potential energy curves (a relationship between the bond length between the N and Ge atoms and the binding energy of the complex). Specifically, we will report here how two nitrogen-donors bond to CF3GeCl3. It was found that CF3-GeCl3-NH3 preferred an axial-equatorial geometry, with the NH3 in the axial position and the CF3 in the equatorial position. The binding energy is 6.6 kcal/mol and the Ge-N bond distance is 2.430 Å. The structure with both the NH3 and the CF3 in the axial position nearly as stable, with a binding energy of 6.4 kcal/mol and a Ge-N bond distance of 2.197 Å. We also examined the analogous CH3CN complex, for which the only stable geometry has the CH3CN in the axial position and the CF3 in the equatorial position. The binding energy was found to be 2.7 kcal/mol, with a Ge-CH3CN bond distance of 3.190 Å. The axial-axial geometry was found to be unstable. We will also present recent results on related systems, such as CF3-GeBr3-NH3 and others that we explore in pursuit of systems with optimal strength and axial – axial geometries.  

Additional Abstract Information

Presenter: Keisha Kappel

Institution: University of Wisconsin - Eau Claire

Type: Poster

Subject: Chemistry

Status: Approved

Time and Location

Session: Poster 4
Date/Time: Tue 11:00am-12:00pm
Session Number: 3622