RESUMO
A comparative study between three experimentally known beryllium chelators (EDTA, NTP, and 10-HBQS) and two tetradentate tripodal di-pyridine-based receptors (HL and HL-NH2), specifically designed to bind Be2+ cations, has been undertaken in the aqueous phase at the B3LYP/6-311++G(d,p) computational level. The relative binding energies of these five ligand systems to a variety of first row and pre-transition metal cations have been calculated, specifically to investigate their binding strength to Be2+ and the binding enhancement that a second sphere hydrogen bonding interaction could afford to the pyridyl based systems. The complexes of EDTA were calculated to have the highest average binding energy; followed by those of NTP, HL-NH2, HL, and finally 10-HBQS. The calculated binding energy of the HL-NH2Be complex, which includes second sphere interactions, was found to be almost 9% greater than the HL Be complex, with an average binding energy increase of 13.5% observed across all metals upon inclusion of second sphere hydrogen bonding.
RESUMO
Two series of tetradentate tripodal di-pyridine-based receptors designed to bind Be2+ cations have been studied in the aqueous phase at the B3LYP/6-311++G(d,p) computational level. The first series comprise simple tetrahedral receptors; the second series incorporates additional scaffolding groups capable of second sphere hydrogen-bonding in order to more finely tune the binding strength towards the Be2+ cation. Out of the five ligand candidates, one containing a tri-pyridyl N-donor along with a phenolato O-donor (L1) exhibited a significant improvement in binding energy stabilisation (47.8 kJ mol-1) towards the Be2+ cation in the presence of second-sphere H-bonding interactions.
RESUMO
At present UK Law states that the unborn child only becomes a legal person invested with legal rights and full protections, like other human persons, at birth. This article critiques the present legal position of setting the threshold for legal personality at birth, showing its inconsistencies and fundamentally pragmatic basis. Against this background, it is argued that a principled approach towards unborn life is necessary, which reflects in law the reality that the unborn child is a type of human person deserving protection as it develops through the continuum of human personhood--from embryonic personhood, to infant personhood and ultimately into adult personhood Human personhood is defined as a union of a material and immaterial self meaning that at every stage of their development they are never a "potential person," but rather a "person with potential" even if it is not actualized through miscarriage, premature death, or disability. This moral and philosophical reasoning is what justifies protecting the sanctity of unborn life in law. The rest of the article explores and critiques the alternative static legal threshold for ascribing legal personality, at conception, implantation and viability. Having considered the practical moral, legal and philosophical problems of these alternatives; the final proposal for law reform combines all three of these thresholds in a proposal for a "dynamic" threshold for legal personality commencing at conception, which would render birth as an irrelevant threshold for moral and legal reasoning about the unborn.