In studies of the chemistry of new copper−nitrosyl complexes supported by tris(3-(trifluoromethyl)-5-methylpyrazol-1-yl)hydroborate (TpCF 3 ,CH 3 ) and tris(3-mesitylpyrazol-1-yl)hydroborate (TpMs,H), significant effects of the scorpionate ligand substituents on the properties of the {CuNO}11 unit were found that have implications for environmental influences on similar species in biological and catalytic systems. The copper(I) complexes TpMs,HCu(THF) and TpCF 3 ,CH 3 Cu(CH3CN) were structurally characterized by X-ray crystallography, and their respective CO and NO adducts were studied by FTIR, EPR, NMR, and/or UV−vis spectroscopies in solution. Both nitrosyl complexes disproportionate in the presence of excess NO to N2O and TpR,R‘Cu(NO2); an X-ray structure of the latter product supported by TpCF 3 ,CH 3 was determined. Unlike previously studied paramagnetic [CuNO]11 compounds that exhibit EPR signals with g < 2.0 and large A NO values at temperatures below ∼40 K (Ruggiero, C. E.; Carrier, S. M.; Antholine, W. E.; Whittaker, J. W.; Cramer, C. J.; Tolman, W. B. J. Am. Chem. Soc. 1993, 115, 11285−11298), TpMs,HCu(NO) is EPR silent at 4.2 K and exhibits an NMR spectrum (238 K, toluene-d 8) with sharp signals. Peak assignments for the NMR spectrum were deduced from integrated intensities, temperature-dependent isotropic shifts, and the nuclear relaxation rates. The unique NMR spectral behavior for the TpMs,H complex, which only differs from those of analogues with simple phenyl substituents by virtue of the shape of the substrate binding pocket enforced by the mesityl methyl groups, suggests that caution should be exercised in characterizing such adducts in proteins and heterogeneous systems; subtle environmental effects may determine the applicability of EPR versus NMR methods. The electron-withdrawing effects of the trifluoromethyl substituents in TpCF 3 ,CH 3 Cu(NO) perturb ν(NO) and the Cu(I) → NO MLCT energy in the respective FTIR and UV−vis spectra and induce a significant slowing of its disproportionation rate. These results, in conjunction with those obtained from kinetic and spectroscopic studies on the TpMs,H system, support a mechanism for the disproportionation involving generation of the CuNO adduct from NO and the Cu(I) precursor in a preequilibrium step, followed by electrophilic attack of a second NO molecule on the adduct that is rate-controlling.

Many studies in the chemical education literature report students' alternative conceptions in chemistry and the difficulty they present for future learning. In this paper, we review existing diagnostic tools used to uncover students' alternative conceptions in chemistry and suggest that there are two fundamental issues with such instruments, namely, the breadth of topics and concepts assessed and the reliance on forced choice responses. We argue that while existing instruments provide a way to assess students' overall understanding of chemical concepts, they cannot assess depth of understanding of any single concept, such as the particulate nature of matter -one of the central, organizing ideas in chemistry. Instead, we propose using qualitative approaches that utilize drawing tasks as an alternative diagnostic tool to uncover students' underlying struggles with fundamental chemistry concepts. Using this approach, we investigated college students' ability to balance chemical equations and draw appropriate particulate representations of those reactions. Emerging categories from students' particulate drawings were coded into several subcategories and revealed a number of underlying issues, such as lack of understanding of appropriate relationships between reacting species in solution, oxidation numbers, states and valences of species, the characteristics and nature of ions in solids and differences between ionic and covalent bonds. We describe these findings and consider the implications of qualitative-based diagnostics for instruction and science learning as a formative assessment tool.

Cooperative learning and inquiry-based pedagogies often present a new paradigm for science teachers in which their traditional role as expert content givers shifts to one of facilitation and coaching. Previous research on these pedagogies in chemistry mainly focused on the structure of the curriculum materials used with these pedagogies and their impact on student achievement. What remains largely unexplored is the nature of teacher’s moves when dialoging with student groups or leading whole class discussions. This study examined the role of teacher-initiated discourses in developing students’ representational fluency with respect to the topic of dissolved ionic compounds in water. Two kinds of teacher-initiated discourse were observed: monologic and dialogic discourse. We describe the nature of these discourses and their impact on student understanding of dissolution processes. We particularly describe certain teacher moves that were found to be more helpful than others when facilitating students’ representational fluency in chemistry.

A significant body of the literature in science education examines students' conceptions of the dissolution of ionic solids in water, often showing that students lack proper understanding of the particulate nature of dissolving materials as well as holding numerous misconceptions about the dissolution process. Consequently, chemical educators have explored several instructional strategies to address this issue including the use of multimedia, computer animations, and hands-on activities. In this paper, we describe the ways in which the use of physical 3D magnetic molecular models during a cooperative inquiry-based activity on chemical bonding prompted classroom discourse on what counts as chemically justifiable and appropriate representations of dissolved ionic solids in water. In so doing, we use the intersection of science education and technology to research the role of models in science teaching, the nature of classroom discourse initiated by modeling activities, and unfolding changes in student conceptions and ultimately student learning.

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A novel mononuclear copper complex of the “NONOate” [Et2N(N2O2)]- has been prepared and its X-ray crystal structure determined (shown). Comparison of rate constants for NO evolution from the complex and from Na[Et2N(N2O2)] revealed that the complex decomposes approximately half as fast as the sodium salt in aqueous solution (pH 7.4, PBS buffer, 37 °C), implicating a decomposition mechanism for the complex different from that postulated for other reported polynuclear copper complexes of this NONOate.

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Student interviews have found an increasingly important place in the educational research landscape. They are used to create and validate assessments and concept inventories, as well as to more clearly elucidate student thinking. One-on-one interviews are most often completed in person at the researcher’s or student’s institution. There are significant advantages, however, of conducting interviews remotely including access to more varied populations, travel-related time and cost savings, and the ability of a single researcher to efficiently collect data at multiple institutions. This paper presents a description of a remote interview process along with details of ways to maintain commonality with its in-person analog. Our research provides evidence that the efficacy of results is maintained and that remote interviews provide a viable alternative to more costly and time-intensive on-site interviews. These results are particularly timely as ways to enable graduate education and research to continue during the COVID-19 pandemic response.