title: Supramolecular Isomerism in a Cadmium Bis(N-Hydroxyethyl, N-isopropyldithiocarbamate) Compound: Physiochemical Characterization of Ball (n = 2) and Chain (n = ∞) Forms of {Cd[S₂CN(iPr)CH₂CH₂OH] ₂•solvent}n

authors: Tan, Yee Seng

abstract: Needles of [{Cd[S₂CN(iPr)CH₂CH₂OH] ₂}₃•MeCN]∞ (2) were harvested from a dry acetonitrile solution of Cd[S₂CN(iPr)CH₂CH₂OH] ₂ after one or two days and proved to be a coordination polymer in which all dithiocarbamate ligands are μ₂,κ²-tridentate, bridging two cadmium atoms and simultaneously chelating one of these. If the same solution was allowed to stand for at least several days, 2 is replaced by blocks comprising a supramolecular isomer of 2, dimeric 1, with formula {Cd[S₂CN(iPr)CH₂CH₂OH] ₂}₂•2H₂O•2MeCN, and two ligands coordinating μ₂,κ² as in 2 and the other two purely κ2-chelating. The time dependency correlates with the pivotal role of water in driving the conversion of “chain” 2 to “ball” 1; crystals of 2 could not be isolated from “wet” acetonitrile. When each of 1 and 2 are dissolved in solution, they exhibit comparable spectroscopic attributes (¹H, ¹³C, and ¹¹³Cd NMR and UV/vis), indicating the solution structures are the same. Both 1 and 2 are luminescent in the solid state with 1 being significantly brighter than 2. Greenockite CdS nanoparticles are generated by the thermal decomposition of both 1 and 2.

text: Supramolecular Isomerism in a Cadmium Bis(N-Hydroxyethyl, N-isopropyldithiocarbamate) Compound: Physiochemical Characterization of Ball (n = 2) and Chain (n = ∞) Forms of {Cd[S₂CN(iPr)CH₂CH₂OH] ₂•solvent}n Needles of [{Cd[S₂CN(iPr)CH₂CH₂OH] ₂}₃•MeCN]∞ (2) were harvested from a dry acetonitrile solution of Cd[S₂CN(iPr)CH₂CH₂OH] ₂ after one or two days and proved to be a coordination polymer in which all dithiocarbamate ligands are μ₂,κ²-tridentate, bridging two cadmium atoms and simultaneously chelating one of these. If the same solution was allowed to stand for at least several days, 2 is replaced by blocks comprising a supramolecular isomer of 2, dimeric 1, with formula {Cd[S₂CN(iPr)CH₂CH₂OH] ₂}₂•2H₂O•2MeCN, and two ligands coordinating μ₂,κ² as in 2 and the other two purely κ2-chelating. The time dependency correlates with the pivotal role of water in driving the conversion of “chain” 2 to “ball” 1; crystals of 2 could not be isolated from “wet” acetonitrile. When each of 1 and 2 are dissolved in solution, they exhibit comparable spectroscopic attributes (¹H, ¹³C, and ¹¹³Cd NMR and UV/vis), indicating the solution structures are the same. Both 1 and 2 are luminescent in the solid state with 1 being significantly brighter than 2. Greenockite CdS nanoparticles are generated by the thermal decomposition of both 1 and 2.

year: 2013

title: Electrospray ionisation - a simple prelude to the understanding of other mass spectrometry techniques

authors: Henderson, William

subjects: mass spectrometry

abstract: Mass spectrometry (MS) is a powerful analytical technique used in the characterisation of a wide range of chemical and biochemical substances. The technique is extensively used in research, across a wide range of disciplines. One of the main strengths of mass spectrometry is that miniscule amounts of sample are typically needed, in the order of micrograms or less. While the study of spectroscopic techniques has been a part of qualifications such as the International Baccalaureate Diploma for some time, ¹ a new Achievement Standard on Spectroscopy has been introduced relatively recently into the New Zealand Chemistry Curriculum, which includes the technique of electron ionisation (El) mass spectrometry.² This article aims to provide, for those perhaps encountering mass spectrometry for the very first time, a short discussion on electrospray ionisation mass spectrometry as an alternative introduction to this important analytical technique.

text: Electrospray ionisation - a simple prelude to the understanding of other mass spectrometry techniques Mass spectrometry (MS) is a powerful analytical technique used in the characterisation of a wide range of chemical and biochemical substances. The technique is extensively used in research, across a wide range of disciplines. One of the main strengths of mass spectrometry is that miniscule amounts of sample are typically needed, in the order of micrograms or less. While the study of spectroscopic techniques has been a part of qualifications such as the International Baccalaureate Diploma for some time, ¹ a new Achievement Standard on Spectroscopy has been introduced relatively recently into the New Zealand Chemistry Curriculum, which includes the technique of electron ionisation (El) mass spectrometry.² This article aims to provide, for those perhaps encountering mass spectrometry for the very first time, a short discussion on electrospray ionisation mass spectrometry as an alternative introduction to this important analytical technique.

year: 2015-07

title: Kai hea te mana o te reo Māori?

authors: Temara, Pou

subjects: Waiata

abstract: Kai roto i tēnei waiata a Te Matua Tangata e kī ana, he mātauranga ake te ruru rāua ko te heihei i te tangata. E taea ana e te ruru rāua ko te heihei te wehewehe i ngā hāora o te pō, i te mea ko te pō te wā rērere o te ruru, ko te pō te wā e tangi ai tōna reo. He mea hanga te ruru mō te pō. Ko tā te heihei he nehu atu i te pō, he whakaō, he karanga i te awatea ki te ao. Kua eke mai te tuarā nui o awatea, kua oho te ao, kua hoki te ruru ki tōna puta, kua ketuketu ko te heihei. Ka pō, kua hoki ko te heihei ki tōna taumatua, kua oho ko te ruru.

text: Kai hea te mana o te reo Māori? Kai roto i tēnei waiata a Te Matua Tangata e kī ana, he mātauranga ake te ruru rāua ko te heihei i te tangata. E taea ana e te ruru rāua ko te heihei te wehewehe i ngā hāora o te pō, i te mea ko te pō te wā rērere o te ruru, ko te pō te wā e tangi ai tōna reo. He mea hanga te ruru mō te pō. Ko tā te heihei he nehu atu i te pō, he whakaō, he karanga i te awatea ki te ao. Kua eke mai te tuarā nui o awatea, kua oho te ao, kua hoki te ruru ki tōna puta, kua ketuketu ko te heihei. Ka pō, kua hoki ko te heihei ki tōna taumatua, kua oho ko te ruru.

year: 2011