This study describes the development and evaluation of a prep course for chemistry graduate teaching assistants (GTAs). The course was developed around three major goals: (i) building a community for new GTAs and socializing them into the department; (ii) modeling teaching with well-documented, innovative teaching and learning techniques; and (iii) helping GTAs to understand their roles within the department and their specific course. The program consisted of a team-taught, six-week course, which was mandatory for first-year GTAs. It was first offered in Fall 2009 (46 students), and then taught again in Fall 2010 (33 students). The course covered multiple topics including student–GTA communication, student assessment, and teaching strategies. End-of-semester surveys, student evaluations of teaching, and interviews with GTAs were used to evaluate the course. Overall, feedback from the course was very positive. GTAs reported that the course benefited them immediately and even more so after they had taught for several semesters. Student evaluations of teaching showed that, on average, first-year GTAs that had completed the prep course in Fall 2009 and Fall 2010 received significantly higher scores than the previous cohort of new GTAs (who had not completed a prep course) on measures such as effective teaching, respecting students, and being prepared.

The mechanisms for the interconversion of facial diastereomers of a variety of TpRe(CO)(L)(eta(2)-L(Ar)) complexes [L = (t)BuNC, pyridine (py), PMe(3), or 1-methylimidazole (MeIm); L(Ar) = benzene, anisole, naphthalene, 1-methylpyrrole, furan, or thiophene; Tp = hydridotris(pyrazolyl)borate] have been investigated by (1)H NMR spin saturation experiments. In addition, the rates and free energies of activation for these processes were calculated from spin saturation experiments and T(1) measurements. The operative mechanisms for interconversion of the pi diastereomers were found to be nondissociative, undergoing either an interfacial or intrafacial linkage isomerization. A comparison of the kinetic parameters for isomerization of related eta(2)-olefin complexes of the [TpRe(CO)(PMe(3))] and [CpRe(NO)(PPh(3))](+) fragments is also presented.

Resonance Raman (rR) spectroscopy was utilized to gain insight into the electronic structure of dppz (dppz ) dipyrido[3,2-a:2′,3′-c]phenazine) complexes of Ru(II) and Os(II). The time-resolved resonance Raman (TR 3 ) spectrum of Ru(phen) 2 (dppz) 2+ (phen ) 1,10-phenanthroline) collected under 355 nm (fwhm ≈ 10 ns) excitation is consistent with the population of a ligand-centered (LC) 3 ππ* state of the dppz ligand. Since emission from the Ru(II) f (dppz) metal-to-ligand charge transfer (MLCT) excited state is observed, both states must possess similar energies. Lowering of the MLCT state energy in Ru(phen) 2 (F 2 -dppz) 2+ and Os(phen) 2 (dppz) 2+ with respect to that of the 3 ππ* state results in the disappearance of the LC 3 ππ* excitedstate peaks in the rR spectrum, indicative of its fast deactivation to the lower MLCT state in these complexes. Addition of DNA to the samples containing Ru(phen) 2 (dppz) 2+ and Ru(phen) 2 (F 2 -dppz) 2+ leads to a decrease in intensity of the peaks associated with the intercalating phenazine part of the dppz ligand. Further increase in the DNA:Ru ratio causes broadening of the spectrum. This broadening has been interpreted in terms of strong ππ interaction between the intercalated dppz ligand and the DNA bases.

A series of complexes of the form TpMo(NO)(L)(η2-Lπ) were synthesized, where Tp = hydridotris(pyrazolyl)borate, L = 1-methylimidazole or ammonia, and Lπ is an alkene, alkyne, ketone, polyaromatic hydrocarbon, or aromatic heterocycle. The thermal stability of the dihapto-coordinated aromatic complexes is indicative of a strong π back-bonding interaction similar to that found in the heavy metal analogues [Os(NH3)5(η2-arene)]2+, TpRe(CO)(L)(η2-arene), and TpW(NO)(L)(η2-arene). Several synthetic routes to these molybdenum complexes are outlined.