title: FTNMR and aspects of germanium chemistry

authors: Watkinson, Philip John

abstract: Experimentally determined baseline parameters were obtained for the NMR observation of 32 isotopes, notably including ⁷³Ge. 
Extensive ⁷³Ge studies were performed, despite the technical difficulties from a low NMR receptivity, and a low observation frequency. The majority of germanium compounds studied gave ⁷³Ge resonances.
Germanium-73 chemical shifts, linewidths, and germanium proton coupling constants have been obtained, doubling the total number of compounds studied directly by ⁷³Ge NMR. Sample concentrations must be typically at least 0.1 M to avoid using excessive instrument time ( > 5 hours).
The larger spectral dispersion of ⁷³Ge NMR than ¹H or ¹³C NMR often makes it a better tool for characterization. Trends in ⁷³Ge chemical shifts and coupling constants are surveyed and their use in characterizing hydrides and organogermanes are illustrated. Germanium-73 NMR gave more spectral information on redistributions in the GeY₄:SiX₄, GeX₄:SnY₄, and GeX₄:HgC1₂ systems than did ²⁹Si, ¹¹⁹Sn, or ¹⁹⁹Hg NMR, revealing a slower redistribution than in MX₄:MY₄ systems (M = Ge or Sn; X, Y = Cl or Br).
Nuclear relaxation studies on ⁷³Ge have been greatly extended, increasing the total number of compounds studied three-fold. Values of T₁ from inversion-recovery experiments ranged from 13 to 1300 ms near RT. The dominance of the quadrupolar relaxation mechanism has been established, and the non-existence of signals from compounds with germanium in an asymmetric environment is attributed to rapid relaxation. Estimates of activation energies for molecular reorientation, and nuclear quadrupole coupling constants (2.3-17 MHz) using ¹³C correlation times have been obtained.
Proton PT to ⁷³Ge via the sequence INEPT was established and its value demonstrated both for sensitivity enhancement and for help in spectral assignment. Observations imply that all compounds with ¹J(Ge,H) or ²J(Ge,C,H) coupling give proton PT. Large enhancements (2-20 fold) were obtained, although long proton T₁ values reduced instrument time savings to 3-100 fold, with the addition of a relaxant in some cases. The loss of signal during the sequence via nuclear relaxation is smaller for INEPT than for another multinuclear PT sequence, UPT, and this difference is maximized for a nucleus with a large spin, like ⁷³Ge. 
Preliminary work on ⁷⁷Se INEPT and multinuclear studies on transition metal carbonyls are presented.

text: FTNMR and aspects of germanium chemistry Experimentally determined baseline parameters were obtained for the NMR observation of 32 isotopes, notably including ⁷³Ge. 
Extensive ⁷³Ge studies were performed, despite the technical difficulties from a low NMR receptivity, and a low observation frequency. The majority of germanium compounds studied gave ⁷³Ge resonances.
Germanium-73 chemical shifts, linewidths, and germanium proton coupling constants have been obtained, doubling the total number of compounds studied directly by ⁷³Ge NMR. Sample concentrations must be typically at least 0.1 M to avoid using excessive instrument time ( > 5 hours).
The larger spectral dispersion of ⁷³Ge NMR than ¹H or ¹³C NMR often makes it a better tool for characterization. Trends in ⁷³Ge chemical shifts and coupling constants are surveyed and their use in characterizing hydrides and organogermanes are illustrated. Germanium-73 NMR gave more spectral information on redistributions in the GeY₄:SiX₄, GeX₄:SnY₄, and GeX₄:HgC1₂ systems than did ²⁹Si, ¹¹⁹Sn, or ¹⁹⁹Hg NMR, revealing a slower redistribution than in MX₄:MY₄ systems (M = Ge or Sn; X, Y = Cl or Br).
Nuclear relaxation studies on ⁷³Ge have been greatly extended, increasing the total number of compounds studied three-fold. Values of T₁ from inversion-recovery experiments ranged from 13 to 1300 ms near RT. The dominance of the quadrupolar relaxation mechanism has been established, and the non-existence of signals from compounds with germanium in an asymmetric environment is attributed to rapid relaxation. Estimates of activation energies for molecular reorientation, and nuclear quadrupole coupling constants (2.3-17 MHz) using ¹³C correlation times have been obtained.
Proton PT to ⁷³Ge via the sequence INEPT was established and its value demonstrated both for sensitivity enhancement and for help in spectral assignment. Observations imply that all compounds with ¹J(Ge,H) or ²J(Ge,C,H) coupling give proton PT. Large enhancements (2-20 fold) were obtained, although long proton T₁ values reduced instrument time savings to 3-100 fold, with the addition of a relaxant in some cases. The loss of signal during the sequence via nuclear relaxation is smaller for INEPT than for another multinuclear PT sequence, UPT, and this difference is maximized for a nucleus with a large spin, like ⁷³Ge. 
Preliminary work on ⁷⁷Se INEPT and multinuclear studies on transition metal carbonyls are presented.

year: 1984

title: The movement of sediment in a channel in relation to magnitude and frequency concepts- a New Zealand example

authors: Pain, C.F.

abstract: In areas where surface wash contributes most of the debris to a channel network, the effect of events of moderate magnitude and frequency appear to be more important than catastrophic events for land form development. In previous studies this idea has been emphasised, largely as a result of the fact that the contribution of bedload to sediment yield has rarely been considered.
Examination of these ideas under certain New Zealand conditions would seem to present a somewhat different picture. Where rapid mass movement is the main contributor of sediment to the channel, both the development of hill-slope form and the movement of sediment in channels must be related to the frequency of occurrence of mass movements. The evidence seems to suggest that most major mass movements are triggered during high-intensity, low-frequency storms.
The Orere River catchment in the Hunua greywacke block of South Auckland, New Zealand, is examined to test these ideas. Although historical data are limited, the character of the sediments in the lower catchment would suggest a succession of major periods of deposition. High-intensity storms of 1966 and 1967 resulted in the deposition of large amounts of material in the channels throughout the catchment, with a gradual removal of material mainly from the upper catchment since that time. From the limited evidence that is available, a simple model of sediment movement through the catchment is presented.

text: The movement of sediment in a channel in relation to magnitude and frequency concepts- a New Zealand example In areas where surface wash contributes most of the debris to a channel network, the effect of events of moderate magnitude and frequency appear to be more important than catastrophic events for land form development. In previous studies this idea has been emphasised, largely as a result of the fact that the contribution of bedload to sediment yield has rarely been considered.
Examination of these ideas under certain New Zealand conditions would seem to present a somewhat different picture. Where rapid mass movement is the main contributor of sediment to the channel, both the development of hill-slope form and the movement of sediment in channels must be related to the frequency of occurrence of mass movements. The evidence seems to suggest that most major mass movements are triggered during high-intensity, low-frequency storms.
The Orere River catchment in the Hunua greywacke block of South Auckland, New Zealand, is examined to test these ideas. Although historical data are limited, the character of the sediments in the lower catchment would suggest a succession of major periods of deposition. High-intensity storms of 1966 and 1967 resulted in the deposition of large amounts of material in the channels throughout the catchment, with a gradual removal of material mainly from the upper catchment since that time. From the limited evidence that is available, a simple model of sediment movement through the catchment is presented.

year: 1970

title: Translated application interfaces - issues of engagement

authors: Mato, Paora James

abstract: In New Zealand, English is the language that dominates contemporary technologies. Usability testing was completed on a range of applications, available with a Māori-language interface, to gauge levels of awareness, engagement and perception. Nearly all of the respondents were unaware of the availability of these interfaces but most indicated they would prefer to use the Māori-language versions. In terms of engagement and usability, users initially engaged using Māori but switched to English when they wanted to quickly complete the task at hand. Few remained fully engaged with the Māori-language interfaces. High levels of language switching were reported and some frustration as the participants encountered new and unfamiliar uses of words. At face value the feedback suggests the translated interfaces contained unnecessary complications and that better design and content might have enhanced the user experience. However, there is evidence that extended use would enable users to become more familiar with the interfaces alluding to initial barriers created by a previous competence in another language -- in this case English. With this previous competence in mind it might be more useful to employ design concepts that would alleviate initial difficulties and serve to keep the user engaged in the target language for longer periods of time.

text: Translated application interfaces - issues of engagement In New Zealand, English is the language that dominates contemporary technologies. Usability testing was completed on a range of applications, available with a Māori-language interface, to gauge levels of awareness, engagement and perception. Nearly all of the respondents were unaware of the availability of these interfaces but most indicated they would prefer to use the Māori-language versions. In terms of engagement and usability, users initially engaged using Māori but switched to English when they wanted to quickly complete the task at hand. Few remained fully engaged with the Māori-language interfaces. High levels of language switching were reported and some frustration as the participants encountered new and unfamiliar uses of words. At face value the feedback suggests the translated interfaces contained unnecessary complications and that better design and content might have enhanced the user experience. However, there is evidence that extended use would enable users to become more familiar with the interfaces alluding to initial barriers created by a previous competence in another language -- in this case English. With this previous competence in mind it might be more useful to employ design concepts that would alleviate initial difficulties and serve to keep the user engaged in the target language for longer periods of time.

year: 2015