title: Preparation of buta-1,3-diynyl complexes of platinum(II) and their use in the construction of neutral molecular squares: synthesis, structural and theoretical characterisation of cyclo-{Pt(µ-C≡CC≡C)(dppe)}₄ and related chemistry

authors: Bruce, Michael I.

subjects: Chemistry

abstract: Copper(I)-catalysed reactions of cis-PtCl₂(L)₂ (L = Pet₃, L₂= dppe, dppp) with buta-1,3-diyne have given the corresponding diynyl complexes, cis-Pt(C≡CC≡CH)2(L)2 (L = Pet₃ 1, L₂= dppe 2, dppp 3) whose solid-state structures have been determined from single crystal X-ray diffraction studies. Theoretical calculations were carried out to probe the electronic structure of these diynyl complexes. Complex 2 reacts with Co₂(CO)₈ to give a bis-adduct 5 and with Ru₃(µ-dppm)(CO)₁₀ to give a mono-adduct 6; in both, the least hindered C≡C triple bond(s) is(are) coordinated. Lithiation (LiBut) of 2 gives a dilithio derivative, which has been converted to dimethyl 7 or mono-SiMe₃ 8 or -Au(PPh₃) 9 complexes. Cu(I) and Ag(I) (MI) adducts ( tweezer  complexes) have been obtained from reactions of 2 with MISCN or [MI(NCMe)₄]⁺. An ES mass spectrometric study of the interactions of 2 with Group 1 cations and with Tl⁺ is also described; comparative experiments with {W(CO)₃Cp}₂(µ-C₈), in which the four C≡C triple bonds do not have a  tweezer  conformation, have also been carried out. The degree of association is determined by the competitive solvation of the Group 1 cation. Coupling of the buta-1,3-diynyl complexes with Pt(OTf)₂(L )₂ gives homo- or mixed-ligand molecular squares cyclo-{(L)₂Pt(µ-C CC C)₂Pt(L )₂}₂ (L, L = Pet₃, L₂, L ₂= dppe, dppp; not all combinations), of which the molecular structure of cyclo-{Pt(µ-C CC C)(dppe)}₄ 17 is described (as solvates containing dmso). The molecular squares form adducts with substituted ammonium triflates [NH₂R₂][OTf] (R = Et, Pri, Cy; NH₂R₂= dbuH) and with Group 11 cations [MI(NCMe)]⁺.

text: Preparation of buta-1,3-diynyl complexes of platinum(II) and their use in the construction of neutral molecular squares: synthesis, structural and theoretical characterisation of cyclo-{Pt(µ-C≡CC≡C)(dppe)}₄ and related chemistry Copper(I)-catalysed reactions of cis-PtCl₂(L)₂ (L = Pet₃, L₂= dppe, dppp) with buta-1,3-diyne have given the corresponding diynyl complexes, cis-Pt(C≡CC≡CH)2(L)2 (L = Pet₃ 1, L₂= dppe 2, dppp 3) whose solid-state structures have been determined from single crystal X-ray diffraction studies. Theoretical calculations were carried out to probe the electronic structure of these diynyl complexes. Complex 2 reacts with Co₂(CO)₈ to give a bis-adduct 5 and with Ru₃(µ-dppm)(CO)₁₀ to give a mono-adduct 6; in both, the least hindered C≡C triple bond(s) is(are) coordinated. Lithiation (LiBut) of 2 gives a dilithio derivative, which has been converted to dimethyl 7 or mono-SiMe₃ 8 or -Au(PPh₃) 9 complexes. Cu(I) and Ag(I) (MI) adducts ( tweezer  complexes) have been obtained from reactions of 2 with MISCN or [MI(NCMe)₄]⁺. An ES mass spectrometric study of the interactions of 2 with Group 1 cations and with Tl⁺ is also described; comparative experiments with {W(CO)₃Cp}₂(µ-C₈), in which the four C≡C triple bonds do not have a  tweezer  conformation, have also been carried out. The degree of association is determined by the competitive solvation of the Group 1 cation. Coupling of the buta-1,3-diynyl complexes with Pt(OTf)₂(L )₂ gives homo- or mixed-ligand molecular squares cyclo-{(L)₂Pt(µ-C CC C)₂Pt(L )₂}₂ (L, L = Pet₃, L₂, L ₂= dppe, dppp; not all combinations), of which the molecular structure of cyclo-{Pt(µ-C CC C)(dppe)}₄ 17 is described (as solvates containing dmso). The molecular squares form adducts with substituted ammonium triflates [NH₂R₂][OTf] (R = Et, Pri, Cy; NH₂R₂= dbuH) and with Group 11 cations [MI(NCMe)]⁺.

year: 2002-01-01

title: Stratigraphy, chronology, and correlation of the Plio-Pleistocene (c. 2.2-0.8 Ma) Kauroa Ash sequence, western central North Island, New Zealand

authors: Horrocks, Joanna L.

abstract: The Kauroa Ash beds (K-beds) comprise a 12-20 m-thick sequence of extremely weathered, clay-rich (40-95% <4 μm clay) beds of tephra and loess, and associated paleosols. Found in isolated remnants throughout the western central North Island, the sequence comprises 15 defined members, with as many as 44 constituent macroscopic beds. The type site, ‘Woodstock’, near Raglan, is the most comprehensive sequence known, but other sites (e.g. Papakura Creek and Tiritirimatangi Peninsula) contain units not found or poorly defined at Woodstock. 

Field properties as well as magnetic susceptibility measurements and particle-size analysis characterise the facies in the sequence. Field properties (in particular colour, consistence, macrofabric) describe the lithostratigraphy. The sequence contains five interpretive (i.e. genetic) ‘facies’: paleosols, primary tephra, very weathered tephra (possibly composite beds), loess and ‘tephric loess’ beds. At least seven loess beds are (newly) identified in the sequence: K4a, K5, K6ai, K8ai, K8bi, K10a and K14ai.

Mass-specific susceptibility and frequency-dependent susceptibility results partly conform to established models (developed mostly on Chinese loess-paleosol deposits) of susceptibility enhancement in paleosols and depletion in loess. Many parts of the sequence do not appear to conform to this model and the results more closely resemble the inverse relationship found on Alaskan loess-paleosol beds. Frequency-dependent susceptibility is reliable in delineating paleosols by their ‘ultrafine’ ferrimagnetic mineral content, and citrate-bicarbonate-dithionite treatments successfully remove all iron oxides so that remeasurement of susceptibility isolates a strictly ‘pedogenic’, rather than lithogenic, fraction. 

Laser diffraction particle-size analysis shows that the Kauroa Ash beds are texturally reasonably homogenous. They have bimodal particle-size distributions with the most dominant mode at around 11.25 ɸ inferred to be the product of intense and prolonged weathering. Other modes are variously centred on 7-8.5 ɸ and, despite weathering and pedogenesis, have some relationship to the original depositional particle-size distributions because trends between facies (i.e. genetic units) are delineated. Principal components analysis objectively characterises these modes as (Wentworth size classes) ‘very fine clay’ and ‘coarse silt’, although there is no proportional relationship between them, supporting a post-depositional origin for the former mode. 

The chronology of the sequence, previously poorly defined, is greatly improved by a combination of tephrochronologic correlations, fission-track dating, and paleomagnetism. Five zircon fission-track dates provide independent age ‘spikes’ and range from 2.24 ± 0.29 Ma in the basal member, K1, to 1.28 ± 0.11 Ma for the distal ignimbrite unit K12a. Paleomagnetism is invaluable in providing additional age information. The top of the sequence, member K15, is dated as >0.78 Ma (Brunhes-Matuyama boundary) because of its reversed polarity; two episodes of normal polarity are found in beds K14b and K2b and are inferred to represent the Jaramillo (1.07-0.99 Ma) and Olduvai (1.95-1.79 Ma) subchrons, respectively. Beds underlying the Kauroa Ash sequence are also of normal polarity, indicating that they were deposited in the Gauss Chron (>2.6 Ma). 

Identification and correlation of tephras by conventional means (fingerprinting by their lithological or geochemical properties) is impossible in the Kauroa Ash sequence because the beds have no remaining volcanic glass, which has instead been altered to an assemblage of authigenic phases (clays) by weathering and pedogenesis. However, a new technique analysing fresh glass found as melt inclusions in quartz grains is successful in circumventing this problem. Inclusions represent samples of non-degassed magma that became entrapped during phenocryst growth prior to eruption. The glass has remained unaltered because it is hermetically sealed in a chemically resistant phenocryst, which has protected it from weathering processes. Electron microprobe analysis of the glass inclusions yield results which are wholly reasonable for glass (totals ranging from 93-97%; low standard deviations of <1 %), and a number of provisional correlations are established by comparing the major element composition of Kauroa Ash tephra beds with those of proximal deposits. The Kauroa Ash sequence may contain deposits correlated with at least seven major TVZ eruptions, in many cases expanding the known extent of the (distal) deposit and, for the first time answering the question as to the origin of the Kauroa Ash beds. 

These correlations, together with an improved chronology, enable the Kauroa Ash sequence to be placed in a regional stratigraphic framework alongside other New Zealand Plio-Pleistocene sequences such as those in the Wanganui Basin, Wairarapa, Cape Kidnappers and Port Waikato. Using paleosols as chrono- and climatostratigraphic entities (correlated to warm periods in global climate), the sequence can also be placed alongside a global reference, the marine oxygen isotope stratigraphy. A further correlation to the Chinese loess-paleosol record suggests that large parts of the Kauroa Ash sequence were deposited in an incremental manner akin to deposition of loess, so that the sequence is not only a record of TVZ volcanism, but also of Plio-Pleistocene paleoclimate.

text: Stratigraphy, chronology, and correlation of the Plio-Pleistocene (c. 2.2-0.8 Ma) Kauroa Ash sequence, western central North Island, New Zealand The Kauroa Ash beds (K-beds) comprise a 12-20 m-thick sequence of extremely weathered, clay-rich (40-95% <4 μm clay) beds of tephra and loess, and associated paleosols. Found in isolated remnants throughout the western central North Island, the sequence comprises 15 defined members, with as many as 44 constituent macroscopic beds. The type site, ‘Woodstock’, near Raglan, is the most comprehensive sequence known, but other sites (e.g. Papakura Creek and Tiritirimatangi Peninsula) contain units not found or poorly defined at Woodstock. 

Field properties as well as magnetic susceptibility measurements and particle-size analysis characterise the facies in the sequence. Field properties (in particular colour, consistence, macrofabric) describe the lithostratigraphy. The sequence contains five interpretive (i.e. genetic) ‘facies’: paleosols, primary tephra, very weathered tephra (possibly composite beds), loess and ‘tephric loess’ beds. At least seven loess beds are (newly) identified in the sequence: K4a, K5, K6ai, K8ai, K8bi, K10a and K14ai.

Mass-specific susceptibility and frequency-dependent susceptibility results partly conform to established models (developed mostly on Chinese loess-paleosol deposits) of susceptibility enhancement in paleosols and depletion in loess. Many parts of the sequence do not appear to conform to this model and the results more closely resemble the inverse relationship found on Alaskan loess-paleosol beds. Frequency-dependent susceptibility is reliable in delineating paleosols by their ‘ultrafine’ ferrimagnetic mineral content, and citrate-bicarbonate-dithionite treatments successfully remove all iron oxides so that remeasurement of susceptibility isolates a strictly ‘pedogenic’, rather than lithogenic, fraction. 

Laser diffraction particle-size analysis shows that the Kauroa Ash beds are texturally reasonably homogenous. They have bimodal particle-size distributions with the most dominant mode at around 11.25 ɸ inferred to be the product of intense and prolonged weathering. Other modes are variously centred on 7-8.5 ɸ and, despite weathering and pedogenesis, have some relationship to the original depositional particle-size distributions because trends between facies (i.e. genetic units) are delineated. Principal components analysis objectively characterises these modes as (Wentworth size classes) ‘very fine clay’ and ‘coarse silt’, although there is no proportional relationship between them, supporting a post-depositional origin for the former mode. 

The chronology of the sequence, previously poorly defined, is greatly improved by a combination of tephrochronologic correlations, fission-track dating, and paleomagnetism. Five zircon fission-track dates provide independent age ‘spikes’ and range from 2.24 ± 0.29 Ma in the basal member, K1, to 1.28 ± 0.11 Ma for the distal ignimbrite unit K12a. Paleomagnetism is invaluable in providing additional age information. The top of the sequence, member K15, is dated as >0.78 Ma (Brunhes-Matuyama boundary) because of its reversed polarity; two episodes of normal polarity are found in beds K14b and K2b and are inferred to represent the Jaramillo (1.07-0.99 Ma) and Olduvai (1.95-1.79 Ma) subchrons, respectively. Beds underlying the Kauroa Ash sequence are also of normal polarity, indicating that they were deposited in the Gauss Chron (>2.6 Ma). 

Identification and correlation of tephras by conventional means (fingerprinting by their lithological or geochemical properties) is impossible in the Kauroa Ash sequence because the beds have no remaining volcanic glass, which has instead been altered to an assemblage of authigenic phases (clays) by weathering and pedogenesis. However, a new technique analysing fresh glass found as melt inclusions in quartz grains is successful in circumventing this problem. Inclusions represent samples of non-degassed magma that became entrapped during phenocryst growth prior to eruption. The glass has remained unaltered because it is hermetically sealed in a chemically resistant phenocryst, which has protected it from weathering processes. Electron microprobe analysis of the glass inclusions yield results which are wholly reasonable for glass (totals ranging from 93-97%; low standard deviations of <1 %), and a number of provisional correlations are established by comparing the major element composition of Kauroa Ash tephra beds with those of proximal deposits. The Kauroa Ash sequence may contain deposits correlated with at least seven major TVZ eruptions, in many cases expanding the known extent of the (distal) deposit and, for the first time answering the question as to the origin of the Kauroa Ash beds. 

These correlations, together with an improved chronology, enable the Kauroa Ash sequence to be placed in a regional stratigraphic framework alongside other New Zealand Plio-Pleistocene sequences such as those in the Wanganui Basin, Wairarapa, Cape Kidnappers and Port Waikato. Using paleosols as chrono- and climatostratigraphic entities (correlated to warm periods in global climate), the sequence can also be placed alongside a global reference, the marine oxygen isotope stratigraphy. A further correlation to the Chinese loess-paleosol record suggests that large parts of the Kauroa Ash sequence were deposited in an incremental manner akin to deposition of loess, so that the sequence is not only a record of TVZ volcanism, but also of Plio-Pleistocene paleoclimate.

year: 2000

title: Mai i te kore, ki te pō, ki te ao mārama: He kohinga pūrākau hauora o ngā kaumātua Māori, Māori Elders health and wellbeing stories in life transitions

authors: Shelford, Pita

subjects: pūrākau

abstract: Introduction
New Zealand’s general population is ageing. Kaumātua (Māori elders) only make up approximately 3.1 percent of the total population and yet, they are disproportionately overrepresented in poor health, wellbeing and ageing statistics. However, this is a one-sided story and the focus of a deficit approach. There is a strong need for a strength-based approach where kaumātua voices of problem-solving and resilience related to ageing and the changes it presents, are heard. The purpose of this study is to identify and share those voices and to respond to the call from Māori academics to apply pūrākau as an alternative to Western narrative approaches. Through a pūrākau approach, this thesis sought to answer three key research questions: 

1)What are the cultural and communication features of the kaumātua teina narratives?
2) What are the cultural and communication characteristics of the kaumātua tuakana conversational styles? and 
3) What is the nature of the kaumātua journeys in how the stories unfold, and relationships develop? 

Methods
This study analyses pūrākau from the Kaumātua Mana Motuhake (KMM) collaboration project between the University of Waikato and the Rauawaawa Kaumātua Charitable Trust in Hamilton, Aotearoa New Zealand. The KMM project sought to enhance kaumātua wellbeing during life changes such as losses of licence, independence or spouse, health changes and retirement through a peer-support tuakana-teina programme. The KMM team implemented a tuakana-teina peer support programme where kaumātua (n= 121) engaged in up to three conversations as kaumātua tuakana-teina pairs. The conversations involved exploring the life changes the teina chose with the tuakana guiding the conversations and sharing potential services to help with the changes.
This thesis analysed 30 kaumātua conversations in 10 tuakana-teina pairs to tell a strengths-based story of health and wellbeing. Taking a Kaupapa Māori approach, the research prioritised, privileged and foregrounded Māori and Indigenous epistemology, ontology, and axiology. A pūrākau-grounded analysis approach was developed and applied to the conversations.

Findings
Related to the first research question, the analysis revealed kaumātua narratives that spoke to stories about adversity, turning points, independence and resilience. Regarding the second research question, the study identified key cultural and communicational characteristics kaumātua tuakana used, speaking with words of kinship and reciprocation, words of ignition and guidance, and words of empathy and affirmation. Pertaining to the third research question, the analysis illustrated conversational and relational journey types kaumātua pairs travelled, consisting of conversations that went direct to topics, detours that became defining moments, small tiki tours that came back to the topic, stories that were revisited, and hospitality becoming defining moments. 

Conclusions
The findings compiled weave a collective tapestry of kaumātua teina pūrākau, kaumātua tuakana communication styles, and kaumātua conversational and relational journeys. Kaumātua teina have voiced a pūrākau for us to understand inter-generational trauma and how cultural connection liberated their wellbeing. Kaumātua tuakana have composed a script of communication protocols emphasising connection and relationship development essential to upholding tikanga (practices, principles, communications). The paired kaumātua journeys have drawn a signposted road map that highlighted journey types, emphasising reciprocity in conversing, learning, guiding, connecting, developing, strengthening and enhancing communications, relationships, and wellbeing

Implications
Via kaumātua conversations, invaluable understandings into Māori and Indigenous wellbeing, ageing and development scholarship are offered, strengthening transformation, leadership and resilience theories. Pūrākau and whanaungatanga (relationships) methodologies are advocated for and culturally responsive research is promoted. Health, wellbeing and ageing programme development, policy and service delivery can be practically informed, accentuating mentorship, intergenerational initiatives, and culturally appropriate kaumātua support. Together, the findings can cultivate community wellbeing and nurture cultural continuity.

text: Mai i te kore, ki te pō, ki te ao mārama: He kohinga pūrākau hauora o ngā kaumātua Māori, Māori Elders health and wellbeing stories in life transitions Introduction
New Zealand’s general population is ageing. Kaumātua (Māori elders) only make up approximately 3.1 percent of the total population and yet, they are disproportionately overrepresented in poor health, wellbeing and ageing statistics. However, this is a one-sided story and the focus of a deficit approach. There is a strong need for a strength-based approach where kaumātua voices of problem-solving and resilience related to ageing and the changes it presents, are heard. The purpose of this study is to identify and share those voices and to respond to the call from Māori academics to apply pūrākau as an alternative to Western narrative approaches. Through a pūrākau approach, this thesis sought to answer three key research questions: 

1)What are the cultural and communication features of the kaumātua teina narratives?
2) What are the cultural and communication characteristics of the kaumātua tuakana conversational styles? and 
3) What is the nature of the kaumātua journeys in how the stories unfold, and relationships develop? 

Methods
This study analyses pūrākau from the Kaumātua Mana Motuhake (KMM) collaboration project between the University of Waikato and the Rauawaawa Kaumātua Charitable Trust in Hamilton, Aotearoa New Zealand. The KMM project sought to enhance kaumātua wellbeing during life changes such as losses of licence, independence or spouse, health changes and retirement through a peer-support tuakana-teina programme. The KMM team implemented a tuakana-teina peer support programme where kaumātua (n= 121) engaged in up to three conversations as kaumātua tuakana-teina pairs. The conversations involved exploring the life changes the teina chose with the tuakana guiding the conversations and sharing potential services to help with the changes.
This thesis analysed 30 kaumātua conversations in 10 tuakana-teina pairs to tell a strengths-based story of health and wellbeing. Taking a Kaupapa Māori approach, the research prioritised, privileged and foregrounded Māori and Indigenous epistemology, ontology, and axiology. A pūrākau-grounded analysis approach was developed and applied to the conversations.

Findings
Related to the first research question, the analysis revealed kaumātua narratives that spoke to stories about adversity, turning points, independence and resilience. Regarding the second research question, the study identified key cultural and communicational characteristics kaumātua tuakana used, speaking with words of kinship and reciprocation, words of ignition and guidance, and words of empathy and affirmation. Pertaining to the third research question, the analysis illustrated conversational and relational journey types kaumātua pairs travelled, consisting of conversations that went direct to topics, detours that became defining moments, small tiki tours that came back to the topic, stories that were revisited, and hospitality becoming defining moments. 

Conclusions
The findings compiled weave a collective tapestry of kaumātua teina pūrākau, kaumātua tuakana communication styles, and kaumātua conversational and relational journeys. Kaumātua teina have voiced a pūrākau for us to understand inter-generational trauma and how cultural connection liberated their wellbeing. Kaumātua tuakana have composed a script of communication protocols emphasising connection and relationship development essential to upholding tikanga (practices, principles, communications). The paired kaumātua journeys have drawn a signposted road map that highlighted journey types, emphasising reciprocity in conversing, learning, guiding, connecting, developing, strengthening and enhancing communications, relationships, and wellbeing

Implications
Via kaumātua conversations, invaluable understandings into Māori and Indigenous wellbeing, ageing and development scholarship are offered, strengthening transformation, leadership and resilience theories. Pūrākau and whanaungatanga (relationships) methodologies are advocated for and culturally responsive research is promoted. Health, wellbeing and ageing programme development, policy and service delivery can be practically informed, accentuating mentorship, intergenerational initiatives, and culturally appropriate kaumātua support. Together, the findings can cultivate community wellbeing and nurture cultural continuity.

year: 2025-11-04