title: Cycloaurated triphenylphosphine-sulfide and –selenide

authors: Kilpin, Kelly Joan

subjects: gold complexes

abstract: The first examples of cycloaurated phosphine sulfides and triphenylphosphine selenide have been synthesised; these complexes are fairly rare examples of gold(III) complexes with potentially reducing sulfur- and selenium-donor ligands. The cycloaurated complex (AuCl₂ (2-C₆H₄P(S)Ph₂) was synthesised in good yield by transmetallation of the organomercury precursor Hg(2-C₆H₄P(S)Ph₂)₂ with Me₄N[AuCl₄]. A route to the chloro-mercury analogue ClHg(2-C₆H₄P(S)Ph₂) was developed by reaction of the cyclomanganated triphenylphosphine sulfide (CO)₄Mn(2-C₆H₄P(S)Ph₂) with HgCl₂; this mercury substrate was also used in the synthesis of AuCl₂(2-C₆H₄P(S)Ph₂). The cycloaurated triphenylphosphine selenide complex AuCl₂(2-C₆H₄P(Se)Ph₂) was synthesised by an analogous methodology using the new phosphine selenide Hg(2-C₆H₄P(Se)Ph₂)₂ [prepared from Hg(2-C₆H₄PPh₂)₂ and elemental Se under sonication]. The phosphonamidic analogue AuCl₂(2-C₆H₄P(S)(Net₂)₂) has also been synthesised from PhP(S)(Net₂)₂via lithiation and mercuration. X-Ray crystal structures of several compounds are reported, and show the presence of puckered ring systems.

text: Cycloaurated triphenylphosphine-sulfide and –selenide The first examples of cycloaurated phosphine sulfides and triphenylphosphine selenide have been synthesised; these complexes are fairly rare examples of gold(III) complexes with potentially reducing sulfur- and selenium-donor ligands. The cycloaurated complex (AuCl₂ (2-C₆H₄P(S)Ph₂) was synthesised in good yield by transmetallation of the organomercury precursor Hg(2-C₆H₄P(S)Ph₂)₂ with Me₄N[AuCl₄]. A route to the chloro-mercury analogue ClHg(2-C₆H₄P(S)Ph₂) was developed by reaction of the cyclomanganated triphenylphosphine sulfide (CO)₄Mn(2-C₆H₄P(S)Ph₂) with HgCl₂; this mercury substrate was also used in the synthesis of AuCl₂(2-C₆H₄P(S)Ph₂). The cycloaurated triphenylphosphine selenide complex AuCl₂(2-C₆H₄P(Se)Ph₂) was synthesised by an analogous methodology using the new phosphine selenide Hg(2-C₆H₄P(Se)Ph₂)₂ [prepared from Hg(2-C₆H₄PPh₂)₂ and elemental Se under sonication]. The phosphonamidic analogue AuCl₂(2-C₆H₄P(S)(Net₂)₂) has also been synthesised from PhP(S)(Net₂)₂via lithiation and mercuration. X-Ray crystal structures of several compounds are reported, and show the presence of puckered ring systems.

year: 2010

title: Suspended solid levels in two chemically dosed sediment retention ponds during earthworks at SH20, Auckland

authors: Jackson, Kate Maree

subjects: Polyaluminium chloride

abstract: Earthworking activities have the potential to accelerate soil erosion through vegetation clearance and soil compaction processes. The eroded sediment can have many detrimental effects on receiving aquatic environments, and thus its discharge is controlled under the Resource Management Act, 1991. Two chemically dosed sediment retentions ponds at the SH20 extension project in Mount Roskill, Auckland were investigated, and the impact of the discharge of one of these ponds on a receiving waterbody was assessed using the Stream Ecological Valuation (SEV) method.

Rainfall and suspended solid data was collected for a nine month period between November 2006 and August 2007, although sampling did not commence at one of the ponds until March 2007. Two SEV samples were undertaken within the receiving waterbody; one in November 2006 and the other in November 2007 to assess environmental changes resulting from the sediment retention pond discharge.

The suspended solids results measured within the sediment retention ponds during this study were much lower than those reported by other studies on earthwork sites. This is believed to be due to the effective implementation of sediment and erosion control measures onsite.

The Somerset Road pond was very effective at removing suspended solids throughout the sampling period, with the majority of suspended solid removal occurring in the forebay as it typically did not become full enough to overflow into the main pond. When the forebay was full of water, the PAC dosing system resulted in large reductions in suspended solid levels over a short horizontal distance within the forebay. A smaller amount of suspended solid reduction was achieved in the main pond, predominately through dilution, with the major function of the main pond being additional storage capacity for runoff. Discharge from the Somerset Road Pond was not continuous due to low water levels in the main pond. However, when discharge did occur, the suspended solids levels were very low compared with other studies investigating sediment retention pond discharge.

The Richardson Road pond was less effective at removing suspended solids due to the flow regime within the forebay. There were two runoff channels entering the forebay, as well as a continual flow of groundwater. Only one of the runoff channels was directly dosed with PAC, and as the water level in the forebay was typically at, or just below, the level spreader at all times, there was a decreased potential for the PAC to become evenly distributed through the forebay and achieve dosing of all runoff. Furthermore, the main pond discharged continuously during the study period, resulting in reduced residence times of runoff within the pond system. Nonetheless, the discharge from the main pond was much lower than other studies, implying suspended solid reduction was being achieved.

The SEV method indicated that the receiving environment was already degraded due to modifications to the riparian vegetation, increased dissolved oxygen demand, and moderate bank erosion. This was reflected in the macroinvertebrate population, with only pollution tolerant taxa being collected, thus limiting the use of macroinvertebrates as an assessment tool in this study. However, the SEV method, which assesses a wide range of ecological functions, implied that very little environmental change occurred as a result of the sediment retention pond discharge. A small increase in deposited sediment was observed on the stream bed, however indications are that deposited sediment is rapidly washed away once earthworks are completed. Thus this deposited sediment may not have a permanent impact within the receiving environment.

text: Suspended solid levels in two chemically dosed sediment retention ponds during earthworks at SH20, Auckland Earthworking activities have the potential to accelerate soil erosion through vegetation clearance and soil compaction processes. The eroded sediment can have many detrimental effects on receiving aquatic environments, and thus its discharge is controlled under the Resource Management Act, 1991. Two chemically dosed sediment retentions ponds at the SH20 extension project in Mount Roskill, Auckland were investigated, and the impact of the discharge of one of these ponds on a receiving waterbody was assessed using the Stream Ecological Valuation (SEV) method.

Rainfall and suspended solid data was collected for a nine month period between November 2006 and August 2007, although sampling did not commence at one of the ponds until March 2007. Two SEV samples were undertaken within the receiving waterbody; one in November 2006 and the other in November 2007 to assess environmental changes resulting from the sediment retention pond discharge.

The suspended solids results measured within the sediment retention ponds during this study were much lower than those reported by other studies on earthwork sites. This is believed to be due to the effective implementation of sediment and erosion control measures onsite.

The Somerset Road pond was very effective at removing suspended solids throughout the sampling period, with the majority of suspended solid removal occurring in the forebay as it typically did not become full enough to overflow into the main pond. When the forebay was full of water, the PAC dosing system resulted in large reductions in suspended solid levels over a short horizontal distance within the forebay. A smaller amount of suspended solid reduction was achieved in the main pond, predominately through dilution, with the major function of the main pond being additional storage capacity for runoff. Discharge from the Somerset Road Pond was not continuous due to low water levels in the main pond. However, when discharge did occur, the suspended solids levels were very low compared with other studies investigating sediment retention pond discharge.

The Richardson Road pond was less effective at removing suspended solids due to the flow regime within the forebay. There were two runoff channels entering the forebay, as well as a continual flow of groundwater. Only one of the runoff channels was directly dosed with PAC, and as the water level in the forebay was typically at, or just below, the level spreader at all times, there was a decreased potential for the PAC to become evenly distributed through the forebay and achieve dosing of all runoff. Furthermore, the main pond discharged continuously during the study period, resulting in reduced residence times of runoff within the pond system. Nonetheless, the discharge from the main pond was much lower than other studies, implying suspended solid reduction was being achieved.

The SEV method indicated that the receiving environment was already degraded due to modifications to the riparian vegetation, increased dissolved oxygen demand, and moderate bank erosion. This was reflected in the macroinvertebrate population, with only pollution tolerant taxa being collected, thus limiting the use of macroinvertebrates as an assessment tool in this study. However, the SEV method, which assesses a wide range of ecological functions, implied that very little environmental change occurred as a result of the sediment retention pond discharge. A small increase in deposited sediment was observed on the stream bed, however indications are that deposited sediment is rapidly washed away once earthworks are completed. Thus this deposited sediment may not have a permanent impact within the receiving environment.

year: 2008

title: Exploring te ao Māori: The role of museums

authors: Clarkin-Phillips, Jeanette

subjects: museum

abstract: Museums offer many opportunities for developing knowledge of the bicultural heritage of Aotearoa New Zealand. This article reports on research involving a kindergarten located in a national museum. It discusses children’s growing understanding of te ao Māori (the world of Māori) through their regular visits to the collections and exhibits in the museum and suggests teachers in early childhood centres may find connecting with their local museum a valuable resource for enhancing bicultural practice.

text: Exploring te ao Māori: The role of museums Museums offer many opportunities for developing knowledge of the bicultural heritage of Aotearoa New Zealand. This article reports on research involving a kindergarten located in a national museum. It discusses children’s growing understanding of te ao Māori (the world of Māori) through their regular visits to the collections and exhibits in the museum and suggests teachers in early childhood centres may find connecting with their local museum a valuable resource for enhancing bicultural practice.

year: 2012