title: Monocations of bismuth and indium in arene media: A spectroscopic and EXAFS investigation

authors: Kuznetsov, Alexei N.

subjects: chemistry

abstract: The composition of In–GaCl₃–benzene and In–BiCl₃–GaCl₃–benzene solutions was investigated by Raman, UV/Vis, 71Ga and 115In NMR spectroscopy as well as by X-ray absorption fine structure spectroscopy (EXAFS). Indium metal was found to be soluble in GaCl₃–benzene solution at room temperature through the reduction of GaIII, producing Ga⁺ and In⁺ species. The subvalent cations are likely to be stabilized by the interaction with benzene. The use of these solutions as reducing media for BiCl₃ leads to the formation of Bi₅3⁺ polycations, with Bi⁺ as an intermediate product. No other subvalent bismuth species were detected. Multinuclear NMR experiments show that the reducing agent is Ga⁺ rather than In⁺. Indium K-edge EXAFS data recorded from solutions without and with subvalent bismuth species present show that In⁺ is co-ordinated by benzene (at about 2.9 Å) and chlorine atoms from chlorometalate anions (at about 3.3 Å) in a formal ratio of 1 2. Electrospray mass spectroscopic data show that In+ is most likely co-ordinated by one arene molecule.

text: Monocations of bismuth and indium in arene media: A spectroscopic and EXAFS investigation The composition of In–GaCl₃–benzene and In–BiCl₃–GaCl₃–benzene solutions was investigated by Raman, UV/Vis, 71Ga and 115In NMR spectroscopy as well as by X-ray absorption fine structure spectroscopy (EXAFS). Indium metal was found to be soluble in GaCl₃–benzene solution at room temperature through the reduction of GaIII, producing Ga⁺ and In⁺ species. The subvalent cations are likely to be stabilized by the interaction with benzene. The use of these solutions as reducing media for BiCl₃ leads to the formation of Bi₅3⁺ polycations, with Bi⁺ as an intermediate product. No other subvalent bismuth species were detected. Multinuclear NMR experiments show that the reducing agent is Ga⁺ rather than In⁺. Indium K-edge EXAFS data recorded from solutions without and with subvalent bismuth species present show that In⁺ is co-ordinated by benzene (at about 2.9 Å) and chlorine atoms from chlorometalate anions (at about 3.3 Å) in a formal ratio of 1 2. Electrospray mass spectroscopic data show that In+ is most likely co-ordinated by one arene molecule.

year: 2000

title: A dramatic landscape

authors: Lowe, David J.

abstract: This chapter introduces the story of Pureora Forest Park (PFP), in the central North Island, New Zealand, by describing the extremely violent Taupo eruption of c. AD 232 and its consequences for the surrounding forests and mountains. It gives a broad-scale local geological history, detailing the origins of some important local sedimentary rocks and landforms with a bearing on the story, including limestone caverns and coal deposits. It describes the location of the future PFP on the western edge of the Taupo Volcanic Zone, and how the history of volcanic activity, together with erosion, have determined much of the character of its landscape, the radial drainage pattern and deep entrenchment of its rivers, the distribution of its vegetation, and its long isolation from human access and permanent settlement.

text: A dramatic landscape This chapter introduces the story of Pureora Forest Park (PFP), in the central North Island, New Zealand, by describing the extremely violent Taupo eruption of c. AD 232 and its consequences for the surrounding forests and mountains. It gives a broad-scale local geological history, detailing the origins of some important local sedimentary rocks and landforms with a bearing on the story, including limestone caverns and coal deposits. It describes the location of the future PFP on the western edge of the Taupo Volcanic Zone, and how the history of volcanic activity, together with erosion, have determined much of the character of its landscape, the radial drainage pattern and deep entrenchment of its rivers, the distribution of its vegetation, and its long isolation from human access and permanent settlement.

year: 2015

title: Toitu Te Moananui a Toi – The Effects of the MV Rena on the Water Quality, Chemistry and Zooplankton of Otaiti (Astrolabe Reef)

authors: Dempsey, Te Puea Toni

subjects: metal contamination

abstract: Humans have had a profound effect on the world’s oceans, particularly through pollution. Marine pollution incidents are particularly important and increasingly involve both petrochemical and metal contamination. The effects of complex high level, point source pollution events such as ship wrecks on larval recruitment to reef environments is not well understood. Larval settlement is heavily influenced by chemical cues, hence pollution events could have a long term influence on reef ecology, and the likelihood that planktonic zooplankton can entrain contaminants into the reef food web is also of concern.
This thesis aims to address concerns from local Tangata Whenua, government, researchers, stakeholders and the public about the long term recovery of Otaiti following the MV Rena shipwreck and subsequent reef contamination. The incident is a complex one involving metallic container debris contamination along with oil. Research focussed on assessing the effects of water borne contamination surrounding the wreck site in order to examine acute and chronic responses of planktonic invertebrates: (1) the influence of Rena and associated debris to the chemistry and quality of water in the benthic zone around the wreck, (2) the toxicity of contaminants to survivorship of zooplankton, and (3) the influence on contaminant plumes to zooplankton recruitment behaviour of Otaiti.
There is a clear effect from the Rena and its associated debris field on the water quality and chemistry of Otaiti. Aluminium and copper for example, were consistently elevated in dissolved and total metal concentrations around the debris field. Laboratory based exposure of zooplankton to realistic concentration gradients of Rena contaminated sediments resulted in increased mortality with increased contaminant concentrations. Behavioural responses of pelagic and settling invertebrates to Rena pollution influenced sediment highlighted sensitivity to associated contaminant plumes. This could have significant ecological implications to the recruitment behaviour of other planktonic organisms that rely on reef conspecifics and chemical cues to initiate settlement.
Ecological concepts such as ecosystem function and biodiversity dynamics (including recruitment) relate the life force and longevity of a system. Key concerns within the scope of this research were highlighted that may have implications to Tangata Whenua decision making in assessing the Mauri of Otaiti. It can be implied that the Rena continues to impact the Mauri of Otaiti due to the presence of contaminants within the debris field.

text: Toitu Te Moananui a Toi – The Effects of the MV Rena on the Water Quality, Chemistry and Zooplankton of Otaiti (Astrolabe Reef) Humans have had a profound effect on the world’s oceans, particularly through pollution. Marine pollution incidents are particularly important and increasingly involve both petrochemical and metal contamination. The effects of complex high level, point source pollution events such as ship wrecks on larval recruitment to reef environments is not well understood. Larval settlement is heavily influenced by chemical cues, hence pollution events could have a long term influence on reef ecology, and the likelihood that planktonic zooplankton can entrain contaminants into the reef food web is also of concern.
This thesis aims to address concerns from local Tangata Whenua, government, researchers, stakeholders and the public about the long term recovery of Otaiti following the MV Rena shipwreck and subsequent reef contamination. The incident is a complex one involving metallic container debris contamination along with oil. Research focussed on assessing the effects of water borne contamination surrounding the wreck site in order to examine acute and chronic responses of planktonic invertebrates: (1) the influence of Rena and associated debris to the chemistry and quality of water in the benthic zone around the wreck, (2) the toxicity of contaminants to survivorship of zooplankton, and (3) the influence on contaminant plumes to zooplankton recruitment behaviour of Otaiti.
There is a clear effect from the Rena and its associated debris field on the water quality and chemistry of Otaiti. Aluminium and copper for example, were consistently elevated in dissolved and total metal concentrations around the debris field. Laboratory based exposure of zooplankton to realistic concentration gradients of Rena contaminated sediments resulted in increased mortality with increased contaminant concentrations. Behavioural responses of pelagic and settling invertebrates to Rena pollution influenced sediment highlighted sensitivity to associated contaminant plumes. This could have significant ecological implications to the recruitment behaviour of other planktonic organisms that rely on reef conspecifics and chemical cues to initiate settlement.
Ecological concepts such as ecosystem function and biodiversity dynamics (including recruitment) relate the life force and longevity of a system. Key concerns within the scope of this research were highlighted that may have implications to Tangata Whenua decision making in assessing the Mauri of Otaiti. It can be implied that the Rena continues to impact the Mauri of Otaiti due to the presence of contaminants within the debris field.

year: 2015