Far infrared fine structure lines in the interstellar medium

Fine structure lines in the far-infrared have many simple properties that make them useful tools for diagnosing astrophysical plasmas. The line ratios are sensitive and accurate probes of density, elemental abundances, and ionization structure. In addition, studies of line shapes and Doppler shifts should prove valuable in studies of the gross dynamics of H II regions and galaxies. We present a review of the theory involved in the interpretation of these lines, and a summary of the observations made so far.Work supported in part by NASA grant NGR 05-003-511.     

The Effectiveness of Process‐Oriented Guided Inquiry Learning to Reduce Alternative Conceptions in Secondary Chemistry

A nonequivalent, control group design was used to investigate student achievement in secondary chemistry. This study investigated the effect of process‐oriented guided inquiry learning (POGIL) in high school chemistry to reduce alternate conceptions related to the particulate nature of matter versus traditional lecture pedagogy. Data were collected from chemistry students in four large high schools and were analyzed using analysis of covariance. The results show that POGIL pedagogy, as opposed to traditional lecture pedagogy, resulted in fewer alternate conceptions related to the particulate nature of matter. Male and female students in the POGIL group posted better posttest scores than their traditional group peers. African‐American and Hispanic students in the POGIL group exhibited achievement gains consistent with Caucasian and Asian students. Further studies are needed to determine the value of POGIL to address achievement gap concerns in chemistry.     

Novel Pyrrolo[2,3-d]pyrimidine Ring forming Methodology

A short, succinct route to biologically active and medicinally important pyrrolo[2,3-d]pyrimidines has been developed starting from readily available acyclic aldehydes. A very efficienttwo step sequence involving a Knoevenagel condensation followed by copper mediated 1,4-conjugate of vinyl magnesium bromide sets up the acyclic precursor. Then, guanidine cyclization followed by a palliduim catalyzed amination reaction or ozonolytic cleavage of the vinyl substituent followed by guanidine cyclization and intramolecular imine formation complete the synthesis.     

Collaborative statistical investigations in diverse settings

This study presents a continuing investigation of influences on outcomes achieved by students working in groups of three on tasks related to chance and data. Earlier research described final mathematical outcomes and identified 17 factors influencing three types of short-term outcomes for groups working in an isolated setting. The current report documents the 17 factors for groups working in a classroom setting and 1654 events for all groups in both settings are identified and each associated with a factor and a short-term outcome. Consideration is then given to variables that have the potential to influence the factors, the short-term outcomes, and their interaction. The overarching variable is the setting within which the collaboration took place. Within each setting, however, two other variables operated: the task carried out, the age/grade of students, gender balance, or collaborative characteristics. The influences of these variables are described within the two settings before consideration is given to the overall influence of the settings.     

Transition-metal-free synthesis of alternating thiophene-perfluoroarene copolymers

The fluoride-activated coupling between silyl-functionalized thiophene monomers and perfluoroarenes leads to moderately high-molecular-weight alternating copolymers in excellent yields and high chemical purity. The method bypasses transition-metal catalysis and the associated need for perfluoroarenes carrying additional functional "handles". Small-molecule model studies provide insight into the relative reactivities of functional groups in this synthetic pathway.     

Molybdocalixarene structure control via rim deprotonation. synthesis, characterization, and crystal structures of calix[4]arene Mo(VI) monooxo complexes and calix[4]arene alkali metal/Mo(VI) dioxo complexes

We report a series of calix[4]arene Mo(VI) dioxo complexes M2RC4MoO2 (M = alkali metal, R = H or Bu(t)) that were fully characterized by NMR, X-ray, IR, UV/vis, and elemental analysis. Molybdocalix[4]arene structures can be controlled via lower rim deprotonation, groups at para positions of calix[4]arene, and alkali metal counterions. Mono deprotonation at the lower rim leads to calix[4]arene Mo(VI) monooxo complexes RC4MoO (R = H, Bu(t), or allyl), and full deprotonation gives rise to calix[4]arene Mo(VI) dioxo complexes. Structural studies indicate that HC4 Mo(VI) dioxo complexes easily form polymeric structures via cation-pi interaction and coordination between different calixarene units. However, Bu(t)C4 Mo(VI) dioxo complexes tend to form dimers or tetramers due to steric hindrance of the tert-butyl groups at para positions in calixarene. The structures of the reduced side products A and C were determined by X-ray diffraction studies. The mechanism of RC4MoO formation from the reaction of calixarene monoanions with MoO2Cl2 appears to include the addition of a calixarene -OH group across a Mo=O bond.