Characterization of Iso -Cf2 I2 in Frequency and Ultrafast Time Domains

The photolysis of diiododifluoromethane (CF2 I2) in condensed phases was studied by a combination of matrix isolation and ultrafast time-resolved spectroscopy, in concert with ab initio calculations. Photolysis at wavelengths of 355 or 266 nm of CF2 I2:Ar samples (1:5000) held at ∼8 K yielded iso -CF2 I2 (F2 C-I-I), a metastable isomer of CF2 I2, characterized here for the first time. The infrared (IR) spectra of this isomer were recorded in matrix experiments, and the derived positions of the C-F stretching modes are in very good agreement with the predictions of high level ab initio calculations, which show that the iso -form is a minimum on the CF2 I2 ground state potential energy surface. The formation of this isomer following 350 nm excitation of CF2 I 2 in room temperature CCl4 solutions was monitored through its intense C-F stretching mode by means of ultrafast time-resolved IR absorption. Together, matrix isolation and ultrafast IR absorption experiments suggest that the formation of iso -CF2 I2 occurs via recombination of CF2 I radical and I atom. Ultrafast IR experiments detect a delayed rise of iso -CF2 I-I absorption, placing an upper limit of 400 fs for the C-I bond dissociation and primary geminate recombination processes. The product absorption spectrum recorded 1 ns after 350 nm excitation of CF2 I2 in solution is virtually identical to the visible absorption spectrum of i so -CF2 I2 trapped in matrix isolation experiments [with subtracted I2 (X) absorption]. The formation of this isomer in solution at room temperature has direct dynamic implications for the ultrafast production of molecular iodine from electronically excited CF 2 I2. © 2010 American Institute of Physics

Neglected diseases of neglected populations: Thinking to reshape the determinants of health in Latin America and the Caribbean

BACKGROUND: People living in poverty throughout the developing world are heavily burdened with neglected communicable diseases and often marginalized by the health sector. These diseases are currently referred to as Neglected Diseases of Neglected Populations. The neglected diseases create social and financial burdens to the individual, the family, the community, and the nation. DISCUSSION: Numerous studies of successful individual interventions to manage communicable disease determinants in various types of communities have been published, but few have applied multiple interventions in an integrated, coordinated manner. We have identified a series of successful interventions and developed three hypothetical scenarios where such interventions could be applied in an integrated, multi-disease, inter-programmatic, and/or inter-sectoral approach for prevention and control of neglected diseases in three different populations: a slum, an indigenous community, and a city with a mix of populations. SUMMARY: The objective of this paper is to identify new opportunities to address neglected diseases, improve community health and promote sustainable development in neglected populations by highlighting examples of key risk and protective factors for neglected diseases which can be managed and implemented through multi-disease-based, integrated, inter-programmatic, and/or inter-sectoral approaches. Based on a literature review, analysis and development of scenarios we visualize how multiple interventions could manage multiple disease problems and propose these as possible strategies to be tested. We seek to stimulate intra- and inter-sectoral dialogue which will help in the construction of new strategies for neglected diseases (particularly for the parasitic diseases) which could benefit the poor and marginalized based on the principle of sustainability and understanding of key determinants of health, and lead to the establishment of pilot projects and activities which can contribute to the achievement of the Millennium Development Goals

Bostonia. Volume 21

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

INFRARED SPECTRAL STUDIES OF ALKALI HALIDE SALT MOLECULE--LEWIS BASE COMPLEXES IN ARGON MATRICES

Author Institution: Department of Chemistry, University of CincinnatiThe reactions of alkali halide salt molecules with a number of Lewis bases have been investigated in argon and nitrogen matrices. Alkali chloride salts, evaporated from a high temperature Knudsen cell, react readily with $H_{2}O$ and $NH_{3}$ to form strongly bound complexes. Intense bands in the regions $3100-3300 \ cm^{-1}$ and $400-500 \ cm^{-1}$ are formed in the $CsCl + (Ar/H_{2}O = 600)$ reaction, and isotopic data using $^{18}O$ and deuterium labeling require a species with two equivalent hydrogen atoms. A structure in which the alkali metal cation is transferred to the base to form a cationic species of the form $(H_{2}OM)^{+}$ ion paired with $Cl^{-}$ is indicated, although a hydrogen bonded form cannot yet be ruled out

INFRARED MATRIX ISOLATION INVESTIGATION OF THE MOLECULAR COMPLEXES OF SILICON AND GERMANIUM TETRAFLUORIDES WITH WEAK LEWIS BASES

Author Institution: Department of Chemistry, University of CincinnatiThe matrix isolation technique has been applied for the study of the intermediate, 1:1 complexes of the Lewis acids $SiF_{4}$ and $GeF_{4}$ with weak Lewis bases, including $CH_{3}CN$ and $HCN$, as well as the stronger base pyridine. All three are characterized by distinct, shifted vibrational modes of both the acid and base subunits; these shifts suggest that the complexes are bound through the nitrogen atom of the base to the silicon or germanium center. The pyridine complexes showed by far the greatest shifts, as well as the highest product yield. The HCN complexes were unusual, in that the HCN act as a Lewis base in this system, contrary to its usual chemical behavior. All of the vibrational modes of the coordinated HCN subunit were observed in the $GeF_{4}$ complex; the C-H stretch shifted $15 cm^{-1}$ to lower energy, the C-N stretch $40 cm^{-1}$ to higher energy, and the bending mode roughly $30 cm^{-1}$ to higher energy. This latter mode did not split upon coordination, suggesting a linear arrangement for the H-C-N-Ge linkage. Additional complexes with weak bases are under investigation, and will be discussed