13 research outputs found
Strong Lewis and BrĂžnsted Acidic Sites in the Borosulfate Mg3[H2OâB(SO4)3]2
Borosulfates provide fascinating structures and properties that go beyond a pure analogy to silicates. Mg-3[H2O -> B(SO4)(3)](2) is the first borosulfate featuring a boron atom solely coordinated by three tetrahedra. Thus, the free Lewis acidic site forms a Lewis acid-base adduct with a water molecule. This is unprecedented for borosulfate chemistry and even for borates. Quantum chemical calculations on water exchange reactions with BF3 and B(C6F5)(3) revealed a higher Lewis acidity for the borosulfate anion. Moreover, proton exchange reactions showed a higher Bronsted acidity than comparable silicates or phosphates. Additionally, Mg-3[H2O -> B(SO4)(3)](2) was characterised by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and density functional theory (DFT) calculations
Strong Lewis and BrĂžnsted acidic sites in the borosulfate Mg3[H2OâB(SO4)3]2
Borosulfates provide fascinating structures and properties that go beyond a pure analogy to silicates. Mg(3)[H(2)OâB(SO(4))(3)](2) is the first borosulfate featuring a boron atom solely coordinated by three tetrahedra. Thus, the free Lewis acidic site forms a Lewis acidâbase adduct with a water molecule. This is unprecedented for borosulfate chemistry and even for borates. Quantum chemical calculations on water exchange reactions with BF(3) and B(C(6)F(5))(3) revealed a higher Lewis acidity for the borosulfate anion. Moreover, proton exchange reactions showed a higher BrĂžnsted acidity than comparable silicates or phosphates. Additionally, Mg(3)[H(2)OâB(SO(4))(3)](2) was characterised by Xâray diffraction, infrared spectroscopy, thermogravimetric analysis, and density functional theory (DFT) calculations
Willingness to use ADHD treatments: A mixed methods study of perceptions by adolescents, parents, health professionals and teachers
Little is known about factors that influence willingness to engage in treatment for attention deficit/hyperactivity disorder (ADHD). From 2007 to 2008, in the context of a longitudinal study assessing ADHD detection and service use in the United States, we simultaneously elicited ADHD treatment perceptions from four stakeholder groups: adolescents, parents, health care professionals and teachers. We assessed their willingness to use ADHD interventions and views of potential undesirable effects of two pharmacological (short- and long-acting ADHD medications) and three psychosocial (ADHD education, behavior therapy, and counseling) treatments. In multiple regression analysis, willingness was found to be significantly related to respondent type (lower for adolescents than adults), feeling knowledgeable, and considering treatments acceptable and helpful, but not significantly associated with stigma/embarrassment, respondent race, gender and socioeconomic status. Because conceptual models of undesirable effects are underdeveloped, we used grounded theory method to analyze open-ended survey responses to the question: âWhat other undesirable effects are you concerned about?â We identified general negative treatment perceptions (dislike, burden, perceived ineffectiveness) and specific undesirable effect expectations (physiological and psychological side-effects, stigma and future dependence on drugs or therapies) for pharmacological and psychosocial treatments. In summary, findings indicate significant discrepancies between teensâ and adultsâ willingness to use common ADHD interventions, with low teen willingness for any treatments. Results highlight the need to develop better treatment engagement practices for adolescents with ADHD