A Series of Crystallographically Characterized Linear and Branched σ-Alkane Complexes of Rhodium: From Propane to 3-Methylpentane.

Using solid-state molecular organometallic (SMOM) techniques, in particular solid/gas single-crystal to single-crystal reactivity, a series of σ-alkane complexes of the general formula [Rh(CyPCHCHPCy)(η:η-alkane)][BAr] have been prepared (alkane = propane, 2-methylbutane, hexane, 3-methylpentane; Ar = 3,5-(CF)CH). These new complexes have been characterized using single crystal X-ray diffraction, solid-state NMR spectroscopy and DFT computational techniques and present a variety of Rh(I)···H-C binding motifs at the metal coordination site: 1,2-η:η (2-methylbutane), 1,3-η:η (propane), 2,4-η:η (hexane), and 1,4-η:η (3-methylpentane). For the linear alkanes propane and hexane, some additional Rh(I)···H-C interactions with the geminal C-H bonds are also evident.

Structural analysis of five-coordinate aluminium(salen) complexes and its relationship to their catalytic activity.

The crystal structure of [Al(tBu-salen)]2O·HCl shows major changes compared to that of [Al(tBu-salen)]2O. The additional proton is localized on the bridging oxygen atom, making the aluminium atoms more electron deficient. As a result, a water molecule coordinates to one of the aluminium atoms, which becomes six-coordinate.

Geminal Diol of Dihydrolevoglucosenone as a Switchable Hydrotrope: A Continuum of Green Nanostructured Solvents.

The addition of water to dihydrolevoglucosenone (Cyrene) creates a solvent mixture with highly unusual properties and the ability to specifically and efficiently solubilize a wide range of organic compounds, notably, aspirin, ibuprofen, salicylic acid, ferulic acid, caffeine, and mandelic acid. The observed solubility enhancement (up to 100-fold) can be explained only by the existence of microenvironments mainly centered on Cyrene's geminal diol. Surprisingly, the latter acts as a reversible hydrotrope and regulates the polarity of the created complex mixture.

Programs to improve adolescent sexual and reproductive health in the US: a review of the evidence.

Background: US adolescents have high rates of teen pregnancy, childbearing, and sexually transmitted infections (STIs), highlighting the need to identify and implement effective programs that will help improve teen sexual and reproductive health.

Materials And Methods: This review identified 103 random-assignment evaluations of 85 programs that incorporated intent-to-treat analyses and assessed impacts on pregnancy, childbearing, STIs, and their key determinants - sexual activity, number of sexual partners, condom use, and other contraceptive use - among teens. This review describes the evidence base for five broad program approaches, including abstinence education, comprehensive sex education, clinic-based programs, youth development programs, and parent-youth relationship programs.

Rapid screening of binding constants by calibrated competitive 1H NMR spectroscopy.

A calibrated competitive NMR method has been developed that is appropriate for the rapid screening of binding constants. This method involves the initial characterisation of a receptor-substrate binding event for which the (1)H NMR spectrum of a given receptor (calibrant) is modified by the substrate of interest at a range of concentrations. For all subsequent "unknown" receptors, K(a) values are then determined by using a competition assay (in the presence of the calibrant receptor) by measuring a single standard (1)H NMR spectrum.