title: Isolation and X-ray structure of the platinum(II)–amidate complex cis-[PtCl{N(CO₂Et)C(O)CH₂CN}(PPh₃)₂], an intermediate in the silver(I) oxide-mediated synthesis of a platinalactam complex

authors: Henderson, William

subjects: Metallacycle complexes

abstract: The reaction of cis-[PtCl₂(PPh₃)₂] with one equivalent of N-cyanoacetylurethane, EtO₂CNHC(O)CH₂CN and silver(I) oxide, in dichloromethane at room temperature for short reaction times gives the complex cis-[PtCl{N(CO₂Et)C(O)CH₂CN}(PPh₃)₂] in high yield. This complex is an intermediate to the previously reported platinalactam complex [Pt{N(CO₂Et)C(O)CHCN}(PPh₃)₂]. The new complex was characterised by multinuclear NMR spectroscopy, electrospray mass spectrometry, and a single-crystal X-ray study. The deprotonated cyanoacetylurethane ligand lies in a plane almost perpendicular to the platinum coordination plane. Other metal oxides were studied in place of silver(I) oxide for the synthesis of the platinum amidate complex, but none were as successful as silver(I) oxide.

text: Isolation and X-ray structure of the platinum(II)–amidate complex cis-[PtCl{N(CO₂Et)C(O)CH₂CN}(PPh₃)₂], an intermediate in the silver(I) oxide-mediated synthesis of a platinalactam complex The reaction of cis-[PtCl₂(PPh₃)₂] with one equivalent of N-cyanoacetylurethane, EtO₂CNHC(O)CH₂CN and silver(I) oxide, in dichloromethane at room temperature for short reaction times gives the complex cis-[PtCl{N(CO₂Et)C(O)CH₂CN}(PPh₃)₂] in high yield. This complex is an intermediate to the previously reported platinalactam complex [Pt{N(CO₂Et)C(O)CHCN}(PPh₃)₂]. The new complex was characterised by multinuclear NMR spectroscopy, electrospray mass spectrometry, and a single-crystal X-ray study. The deprotonated cyanoacetylurethane ligand lies in a plane almost perpendicular to the platinum coordination plane. Other metal oxides were studied in place of silver(I) oxide for the synthesis of the platinum amidate complex, but none were as successful as silver(I) oxide.

year: 2000-01-01

title: The inter-valley soil comparative survey: the ecology of Dry Valley edaphic microbial communities

authors: Lee, Charles Kai-Wu

subjects: Antarctica

abstract: Recent applications of molecular genetics to edaphic microbial communities of the McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey aims to elucidate the factors shaping these unique microbial communities and their biogeography by integrating molecular genetic approaches with biogeochemical analyses. Although the microbial communities of Dry Valley soils may be complex, there is little doubt that the ecosystem's food web is relatively simple, and evidence suggests that physicochemical conditions may have the dominant role in shaping microbial communities. To examine this hypothesis, bacterial communities from representative soil samples collected in four geographically disparate Dry Valleys were analyzed using molecular genetic tools, including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four communities are structurally and phylogenetically distinct, and possess significantly different levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys, challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content, alongside altitude and Cu2+, was significantly correlated with differences in microbial communities. Our results indicate that the microbial ecology of Dry Valley soils is highly localized and that physicochemical factors potentially have major roles in shaping the microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley glacial geomorphology and microbial ecology, and raise previously unrecognized issues related to environmental management of this unique ecosystem.

text: The inter-valley soil comparative survey: the ecology of Dry Valley edaphic microbial communities Recent applications of molecular genetics to edaphic microbial communities of the McMurdo Dry Valleys and elsewhere have rejected a long-held belief that Antarctic soils contain extremely limited microbial diversity. The Inter-Valley Soil Comparative Survey aims to elucidate the factors shaping these unique microbial communities and their biogeography by integrating molecular genetic approaches with biogeochemical analyses. Although the microbial communities of Dry Valley soils may be complex, there is little doubt that the ecosystem's food web is relatively simple, and evidence suggests that physicochemical conditions may have the dominant role in shaping microbial communities. To examine this hypothesis, bacterial communities from representative soil samples collected in four geographically disparate Dry Valleys were analyzed using molecular genetic tools, including pyrosequencing of 16S rRNA gene PCR amplicons. Results show that the four communities are structurally and phylogenetically distinct, and possess significantly different levels of diversity. Strikingly, only 2 of 214 phylotypes were found in all four valleys, challenging a widespread assumption that the microbiota of the Dry Valleys is composed of a few cosmopolitan species. Analysis of soil geochemical properties indicated that salt content, alongside altitude and Cu2+, was significantly correlated with differences in microbial communities. Our results indicate that the microbial ecology of Dry Valley soils is highly localized and that physicochemical factors potentially have major roles in shaping the microbiology of ice-free areas of Antarctica. These findings hint at links between Dry Valley glacial geomorphology and microbial ecology, and raise previously unrecognized issues related to environmental management of this unique ecosystem.

year: 2011

title: Who owns native nature? Discourses of rights to land, culture, and knowledge in New Zealand

authors: Goldsmith, Michael

subjects: indigenous cultures

abstract: Michael Brown famously asked ‘Who owns native culture?’ This paper revisits that question by analyzing what happens to culture when the culturally defined boundary between it and nature becomes salient in the context of disputes between indigenous and settler populations. My case study is the dispute between the New Zealand government and Maori tribal groupings concerning ownership of the foreshore and seabed. Having been granted the right to test their claims in court in 2003, Maori groups were enraged when the government legislated the right out of existence in 2004. Though the reasons for doing so were clearly political, contrasting cultural assumptions appeared to set Maori and Pakeha (New Zealanders of European origin) at odds. While couching ownership of part of nature as an IPR issue may seem counter-intuitive, I argue that as soon as a property claim destabilizes the nature/culture boundary, IPR discourse becomes pertinent.

text: Who owns native nature? Discourses of rights to land, culture, and knowledge in New Zealand Michael Brown famously asked ‘Who owns native culture?’ This paper revisits that question by analyzing what happens to culture when the culturally defined boundary between it and nature becomes salient in the context of disputes between indigenous and settler populations. My case study is the dispute between the New Zealand government and Maori tribal groupings concerning ownership of the foreshore and seabed. Having been granted the right to test their claims in court in 2003, Maori groups were enraged when the government legislated the right out of existence in 2004. Though the reasons for doing so were clearly political, contrasting cultural assumptions appeared to set Maori and Pakeha (New Zealanders of European origin) at odds. While couching ownership of part of nature as an IPR issue may seem counter-intuitive, I argue that as soon as a property claim destabilizes the nature/culture boundary, IPR discourse becomes pertinent.

year: 2009