RESUMO
Pd2dba3·CHCl3 (2.5 mol%)-BINAPHANE (5 mol%) was used to promote the first catalytic enantioselective allylation of disubstituted ketenes to give α-allyl esters. The ester products were formed in good to excellent yields (61-93% yield for 13 examples, 16 examples in all), with moderate to good enantioselectivity (68-80% ee for 7 examples).
RESUMO
Molecular dynamics (MD) at the molecular mechanical level and geometry optimisation at the quantum mechanical level have been performed to investigate the transport and fixation of oxygen and carbon dioxide in the cavity of ribulose-1,5-bisphosphate carboxylase/oxygenase, or Rubisco. Multiple MD simulations have been carried out to study the diffusive behaviour of O(2) and CO(2) molecules from the Mg(2+) cation in Rubisco at 298 K and 1 bar, being one step in the overall process of carboxylation/oxygenation in Rubisco. In addition to this work, in order to gain additional perspective on the role of chemical reaction rates and thermodynamics, oxygen, and carbon dioxide uptake mechanisms have also been investigated by the aid of quantum chemical calculations. The results indicate that the activation barrier for carboxylation is slightly lower than that of oxygenation. This agrees qualitatively with experimental findings, and rationalises the observed competition between both catalytic processes in nature. Finally, the longer-lived persistence of CO(2) in the vicinity of the active centre (i.e., slower self-diffusion) may serve to explain, in part, why carboxylation is the more kinetically favoured on an overall basis compared to oxygenation.
Assuntos
Dióxido de Carbono/metabolismo , Domínio Catalítico , Simulação de Dinâmica Molecular , Oxigênio/metabolismo , Teoria Quântica , Ribulose-Bifosfato Carboxilase/química , Ribulose-Bifosfato Carboxilase/metabolismo , Difusão , Cinética , Spinacia oleracea/enzimologia , TermodinâmicaRESUMO
This chapter will discuss the ongoing development and integration of micro and nano technologies within the Tyndall National Institute that will enable the future vision of ambient intelligence with specific application to the area of personalised health (P-Health). Ambient Intelligent Systems open entirely new possibilities for future applications and resultant markets. Ultimately, these systems will create intelligent environments that cater continuously for the requirements of the individual in everyday life and apply it in a totally coherent manner. They will learn and evolve to anticipate user-requirements. We will discuss ongoing research in the areas of sensors, sensor interfacing, interconnection and packaging, hardware platforms, infrastructure and power delivery for ambient systems with applications in the p-health domain.