A report on the Gascoyne River catchment following the 2010/11 flood events

In December 2010 an extreme tropical storm resulted in widespread flooding at Carnarvon and across the catchment. Another two flood events followed during the summer of 2010–11 The rationale for this assessment is to provide illustrative evidence on the role that perennial vegetation groundcover management has in influencing the risk of flooding and soil loss in the catchment. It may be possible that the impact of flooding associated with extreme storm events can be reduced. This report focuses on catchment condition and is not a review of the pastoral industry’s economic viability

The role of neutral Rh(PONOP)H, free NMe2H, boronium and ammonium salts in the dehydrocoupling of dimethylamine-borane using the cationic pincer [Rh(PONOP)(η2-H2)]+ catalyst

The σ-amine-borane pincer complex [Rh(PONOP)(η1-H3B·NMe3)][BArF4] [2, PONOP = κ3-NC5H3-2,6-(OPtBu2)2] is prepared by addition of H3B·NMe3 to the dihydrogen precursor [Rh(PONOP)(η2-H2)][BArF4], 1. In a similar way the related H3B·NMe2H complex [Rh(PONOP)(η1-H3B·NMe2H)][BArF4], 3, can be made in situ, but this undergoes dehydrocoupling to reform 1 and give the aminoborane dimer [H2BNMe2]2. NMR studies on this system reveal an intermediate neutral hydride forms, Rh(PONOP)H, 4, that has been prepared independently. 1 is a competent catalyst (2 mol%, ∼30 min) for the dehydrocoupling of H3B·Me2H. Kinetic, mechanistic and computational studies point to the role of NMe2H in both forming the neutral hydride, via deprotonation of a σ-amine-borane complex and formation of aminoborane, and closing the catalytic cycle by reprotonation of the hydride by the thus-formed dimethyl ammonium [NMe2H2]+. Competitive processes involving the generation of boronium [H2B(NMe2H)2]+ are also discussed, but shown to be higher in energy. Off-cycle adducts between [NMe2H2]+ or [H2B(NMe2H)2]+ and amine-boranes are also discussed that act to modify the kinetics of dehydrocoupling

A report on the Gascoyne River catchment following the 2010/11 flood events

In December 2010 an extreme tropical storm resulted in widespread flooding at Carnarvon and across the catchment. Another two flood events followed during the summer of 2010–11 The rationale for this assessment is to provide illustrative evidence on the role that perennial vegetation groundcover management has in influencing the risk of flooding and soil loss in the catchment. It may be possible that the impact of flooding associated with extreme storm events can be reduced. This report focuses on catchment condition and is not a review of the pastoral industry’s economic viability