title: Probing the Lewis basicity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] on tin substrates by electrospray mass spectrometry

authors: Yeo, Jeremy S.L.

subjects: chemistry

abstract: Electrospray Mass Spectrometry (ESMS) has been used as a tool to probe the reactivity of [Pt₂(μ-Se)₂(PPh₃)₄] with tin(IV) substrates, which leads to the formation of charged coordination complexes via loss of halides. The metal substrates used in the displacement reactions are SnRxCl4 – x (x = 1, R = Me, Bu or Ph; x = 2, R = Me, Bu, Et or Ph; x = 3, R = Me, Ph) and Sn(CH₂Ph)₂Br₂. Most of these reactions gave both mono- and di-cations through displacement of one and two halides respectively by [Pt₂(μ-Se)₂(PPh₃)₄]. ESMS was also used to monitor the progress of reactions. The products, upon isolation, were also characterized by NMR and X-ray single crystal crystallographic analysis. The crystal structures of the aggregates [Pt₂(μ₃-Se)₂(PPh₃)₄(SnBuCl₂)][PF₆], [Pt₂(μ₃-Se)₂(PPh₃)₄(SnBu₂Cl)][PF₆] and [Pt₂(μ₃-Se)₂(PPh₃)₄(SnMe₂Cl)][PF₆] are reported and discussed.

text: Probing the Lewis basicity of the metalloligand [Pt₂(μ-Se)₂(PPh₃)₄] on tin substrates by electrospray mass spectrometry Electrospray Mass Spectrometry (ESMS) has been used as a tool to probe the reactivity of [Pt₂(μ-Se)₂(PPh₃)₄] with tin(IV) substrates, which leads to the formation of charged coordination complexes via loss of halides. The metal substrates used in the displacement reactions are SnRxCl4 – x (x = 1, R = Me, Bu or Ph; x = 2, R = Me, Bu, Et or Ph; x = 3, R = Me, Ph) and Sn(CH₂Ph)₂Br₂. Most of these reactions gave both mono- and di-cations through displacement of one and two halides respectively by [Pt₂(μ-Se)₂(PPh₃)₄]. ESMS was also used to monitor the progress of reactions. The products, upon isolation, were also characterized by NMR and X-ray single crystal crystallographic analysis. The crystal structures of the aggregates [Pt₂(μ₃-Se)₂(PPh₃)₄(SnBuCl₂)][PF₆], [Pt₂(μ₃-Se)₂(PPh₃)₄(SnBu₂Cl)][PF₆] and [Pt₂(μ₃-Se)₂(PPh₃)₄(SnMe₂Cl)][PF₆] are reported and discussed.

year: 2001

title: The Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period) in the NGRIP ice core

authors: Walker, Mike

subjects: Geoscience

abstract: The Greenland ice core from NorthGRIP (NGRIP) contains a proxy climate record across the Pleistocene– Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision. This climatic event is most clearly reflected in an abrupt shift in deuterium excess values, accompanied by more gradual changes in d18O, dust concentration, a range of chemical species, and annual layer thickness. A timescale based on multi-parameter annual layer counting provides an age of 11,700 yr b2k (before AD2000) for the base of the Holocene, with an estimated 2s uncertainty of 99 yr. It is proposed that an archived core from this unique sequence should constitute the Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period).

text: The Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period) in the NGRIP ice core The Greenland ice core from NorthGRIP (NGRIP) contains a proxy climate record across the Pleistocene– Holocene boundary of unprecedented clarity and resolution. Analysis of an array of physical and chemical parameters within the ice enables the base of the Holocene, as reflected in the first signs of climatic warming at the end of the Younger Dryas/Greenland Stadial 1 cold phase, to be located with a high degree of precision. This climatic event is most clearly reflected in an abrupt shift in deuterium excess values, accompanied by more gradual changes in d18O, dust concentration, a range of chemical species, and annual layer thickness. A timescale based on multi-parameter annual layer counting provides an age of 11,700 yr b2k (before AD2000) for the base of the Holocene, with an estimated 2s uncertainty of 99 yr. It is proposed that an archived core from this unique sequence should constitute the Global Stratotype Section and Point (GSSP) for the base of the Holocene Series/Epoch (Quaternary System/Period).

year: 2008-06

title: Approaching Māori language through meaning: The predominance of Indo-European models of relationships within propositions

authors: Whaanga, Hēmi

subjects: Te reo Māori

abstract: In every language, there are relationships between predicators (such as, for example, 'go'/'haere') and arguments (such as, for example, ‘James'/'Hēmi’). One such relationship that has been proposed is that of agency. Thus, in 'James goes'/ ‘E haere ana a Hēmi’), 'James'/'Hēmi' can be said to be the agent of the action 'go'/'haere'. Much of the international literature on relationships of this type is based on research on English and it has been claimed that the relationships that have been identified are universals. However, there may be differences among languages, differences that are attributable to the fact that different languages encode different ways of perceiving divisions in perceptual space. My aim here is to demonstrate, with reference to a number of different models of predicator/ argument relations, that most of them are based on assumptions that derive from the structure of Indo-European languages, English in particular. In Part 2 of this paper (to appear in a subsequent issue of this Journal), the implications of this discussion will be examined with reference to an analysis of Māori in terms of relationships within propositions.

text: Approaching Māori language through meaning: The predominance of Indo-European models of relationships within propositions In every language, there are relationships between predicators (such as, for example, 'go'/'haere') and arguments (such as, for example, ‘James'/'Hēmi’). One such relationship that has been proposed is that of agency. Thus, in 'James goes'/ ‘E haere ana a Hēmi’), 'James'/'Hēmi' can be said to be the agent of the action 'go'/'haere'. Much of the international literature on relationships of this type is based on research on English and it has been claimed that the relationships that have been identified are universals. However, there may be differences among languages, differences that are attributable to the fact that different languages encode different ways of perceiving divisions in perceptual space. My aim here is to demonstrate, with reference to a number of different models of predicator/ argument relations, that most of them are based on assumptions that derive from the structure of Indo-European languages, English in particular. In Part 2 of this paper (to appear in a subsequent issue of this Journal), the implications of this discussion will be examined with reference to an analysis of Māori in terms of relationships within propositions.

year: 2001-09