ABSTRACT
The rational development of homogeneous catalytic systems for selective aerobic oxidations of organics has been hampered by the limited available knowledge of how oxygen reacts with important organometallic intermediates. Recently, several mechanisms for oxygen insertion into late transition metal-hydride bonds have been described. Contributing to this nascent understanding of how oxygen reacts with metal-hydrides, a detailed mechanistic study of the reaction of oxygen with the IrIII hydride complex (dmPhebox)Ir(OAc)(H) (1) in the presence of acetic acid, which proceeds to form the IrIII complex (dmPhebox)Ir(OAc)2(OH2) (2), is described. The evidence supports a multifaceted mechanism wherein a small amount of an initially formed metal hydroperoxide proceeds to generate a metal-oxyl species that then initiates a radical chain reaction to rapidly convert the remaining IrIII-H. Insight into the initiation step was gained through kinetic and mechanistic studies of the radical chain inhibition by BHT (butylated hydroxytoluene). Computational studies were employed to contribute to a further understanding of initiation and propagation in this system.
ABSTRACT
We sought to examine correlations between international backpackers' alcohol consumption and sexual behaviors and determine the prevalence of Chlamydia trachomatis and Neisseria gonorrhoea in this population. A cross-sectional study design consisting of a convenience sample (N = 168) of non-treatment-seeking international backpackers visiting Brisbane, Australia was recruited. Participants were asked to self-complete a questionnaire on sexual behavior and to undertake a urine-based polymerase chain reaction test for C trachomatis and N gonorrhoea. Since arriving in Australia, 73.2% reported having had sex, with a median number of 2 different sex partners (range = 0-21). Most participants had consumed alcohol (53.7%) and used condoms (46.3%) the last time they had sex. In our sample, there was a 4.3% prevalence of C trachomatis and a 0% prevalence of N gonorrhoea. This study identified a variable pattern of risk among backpackers, with those spending longer periods in the country more likely to have sex with Australians.
