title: The synthesis of water-soluble analogues of Pt₂(μ₂-S)₂(PPh₃)₄

authors: Sutton, Ryan

subjects: Chemistry

abstract: Platinum has a very rich chemistry with sulfur, and this field has been extensively studied. Of particular interest are complexes containing the {Pt₂(μ₂-S)₂} core, comprising two platinum atoms with μ₂-sulfurs bridging through a flexible hinge. These complexes can act as potent metalloligands (through the two sulfurs) toward a wide range of transition metal and other centres, allowing for the synthesis of complexes with trinuclear mixed-metal cores {Pt₂(μ₃-S)₂M} (M = heterometal). The {Pt₂(μ₂-S)₂} core is also highly nucleophilic and alkylated by the mildest of reagents. The ancillary ligands coordinated to the {Pt₂(μ₂-S)₂} core are primarily triphenylphosphine (PPh₃), resulting in the complexes being significantly insoluble in water, preventing any forms of bioactivity or biphasic catalysis from being assessed.
This research project has widened the scope of {Pt₂(μ₂-S)₂} complexes via the synthesis of the new water-soluble complexes {Pt₂(μ₂-S)₂}(PTA)₄, [Pt₂(μ₃- S)₂(PTA)₄Rh(cod)]Cl, and [Pt₃(μ3-S)₂(PTA)6]²⁺ (PTA = 1,3,5-triaza-7- phosphaadamantane, cod = 1,5-cyclooctadiene) that were characterised by electrospray ionisation mass spectrometry (ESI-MS) and phosphorus-31 nuclear magnetic resonance spectroscopy (³¹P{¹H} NMR). The complex [Pt₃(μ₃- S)₂(PTA)₆]²⁺ was synthesised during the research into the use of a sulfide exchange column as an alternative source of sulfide for the synthesis of Pt₂(μ₂- S)₂(PTA)₄.
The water-soluble phosphine ligands tris(2-carboxyethyl)phosphine (TCEP) and monosulfonated triphenylphosphine [TPPMS]⁻ were determined to be unsuitable ligands for complexes of the general form {Pt₂(μ₂-S)₂}(L)₄ (L = TCEP, [TPPMS]⁻). During these attempted syntheses the complex {Pt₂(μ₂-S)₂} (cod)₂ was successfully produced and characterised with ESI-MS, ¹H NMR, ¹H-¹H COSY, and ¹³C-¹H HSQC (Proton nuclear magnetic resonance spectroscopy, Correlation Spectroscopy, Heteronuclear Single Quantum Coherence).
The use of thioacetamide (CH₂C(S)NH₂) as an alternative source of sulfide in the synthesis of {Pt₂(μ₂-S)₂}(PPh₃)₄ was found to be a poor substitute for the well established Na₂S·9H₂O. The reaction does result in [Pt(CH₃C(S)NH)(PPh₃)₂]⁺+, subsequently isolated as the BPh₄- salt, [Pt(CH₃C(S)NH)(PPh₃)₂](BPh₄) and was characterised by ESI-MS and ³¹P{1H} NMR. The X-ray crystal structure of the by-product trans-Pt(SC(O)CH₃)₂(PPh₃)₂ was obtained.

text: The synthesis of water-soluble analogues of Pt₂(μ₂-S)₂(PPh₃)₄ Platinum has a very rich chemistry with sulfur, and this field has been extensively studied. Of particular interest are complexes containing the {Pt₂(μ₂-S)₂} core, comprising two platinum atoms with μ₂-sulfurs bridging through a flexible hinge. These complexes can act as potent metalloligands (through the two sulfurs) toward a wide range of transition metal and other centres, allowing for the synthesis of complexes with trinuclear mixed-metal cores {Pt₂(μ₃-S)₂M} (M = heterometal). The {Pt₂(μ₂-S)₂} core is also highly nucleophilic and alkylated by the mildest of reagents. The ancillary ligands coordinated to the {Pt₂(μ₂-S)₂} core are primarily triphenylphosphine (PPh₃), resulting in the complexes being significantly insoluble in water, preventing any forms of bioactivity or biphasic catalysis from being assessed.
This research project has widened the scope of {Pt₂(μ₂-S)₂} complexes via the synthesis of the new water-soluble complexes {Pt₂(μ₂-S)₂}(PTA)₄, [Pt₂(μ₃- S)₂(PTA)₄Rh(cod)]Cl, and [Pt₃(μ3-S)₂(PTA)6]²⁺ (PTA = 1,3,5-triaza-7- phosphaadamantane, cod = 1,5-cyclooctadiene) that were characterised by electrospray ionisation mass spectrometry (ESI-MS) and phosphorus-31 nuclear magnetic resonance spectroscopy (³¹P{¹H} NMR). The complex [Pt₃(μ₃- S)₂(PTA)₆]²⁺ was synthesised during the research into the use of a sulfide exchange column as an alternative source of sulfide for the synthesis of Pt₂(μ₂- S)₂(PTA)₄.
The water-soluble phosphine ligands tris(2-carboxyethyl)phosphine (TCEP) and monosulfonated triphenylphosphine [TPPMS]⁻ were determined to be unsuitable ligands for complexes of the general form {Pt₂(μ₂-S)₂}(L)₄ (L = TCEP, [TPPMS]⁻). During these attempted syntheses the complex {Pt₂(μ₂-S)₂} (cod)₂ was successfully produced and characterised with ESI-MS, ¹H NMR, ¹H-¹H COSY, and ¹³C-¹H HSQC (Proton nuclear magnetic resonance spectroscopy, Correlation Spectroscopy, Heteronuclear Single Quantum Coherence).
The use of thioacetamide (CH₂C(S)NH₂) as an alternative source of sulfide in the synthesis of {Pt₂(μ₂-S)₂}(PPh₃)₄ was found to be a poor substitute for the well established Na₂S·9H₂O. The reaction does result in [Pt(CH₃C(S)NH)(PPh₃)₂]⁺+, subsequently isolated as the BPh₄- salt, [Pt(CH₃C(S)NH)(PPh₃)₂](BPh₄) and was characterised by ESI-MS and ³¹P{1H} NMR. The X-ray crystal structure of the by-product trans-Pt(SC(O)CH₃)₂(PPh₃)₂ was obtained.

year: 2019

title: Improving access to large-scale digital libraries through semantic-enhanced search and disambiguation

authors: Hinze, Annika

subjects: computer science

abstract: With 13,000,000 volumes comprising 4.5 billion pages of text, it is currently very difficult for scholars to locate relevant sets of documents that are useful in their research from the HathiTrust Digital Libary (HTDL) using traditional lexically-based retrieval techniques. Existing document search tools and document clustering approaches use purely lexical analysis, which cannot address the inherent ambiguity of natural language. A semantic search approach offers the potential to overcome the shortcoming of lexical search, but even if an appropriate network of ontologies could be decided upon it would require a full semantic markup of each document. In this paper, we present a conceptual design and report on the initial implementation of a new framework that affords the benefits of semantic search while minimizing the problems associated with applying existing semantic analysis at scale. Our approach avoids the need for complete semantic document markup using pre-existing ontologies by developing an automatically generated Concept-in-Context (CiC) network seeded by a priori analysis of Wikipedia texts and identification of semantic metadata. Our Capisco system analyzes documents by the semantics and context of their content. The disambiguation of search queries is done interactively, to fully utilize the domain knowledge of the scholar. Our method achieves a form of semantic-enhanced search that simultaneously exploits the proven scale benefits provided by lexical indexing.

text: Improving access to large-scale digital libraries through semantic-enhanced search and disambiguation With 13,000,000 volumes comprising 4.5 billion pages of text, it is currently very difficult for scholars to locate relevant sets of documents that are useful in their research from the HathiTrust Digital Libary (HTDL) using traditional lexically-based retrieval techniques. Existing document search tools and document clustering approaches use purely lexical analysis, which cannot address the inherent ambiguity of natural language. A semantic search approach offers the potential to overcome the shortcoming of lexical search, but even if an appropriate network of ontologies could be decided upon it would require a full semantic markup of each document. In this paper, we present a conceptual design and report on the initial implementation of a new framework that affords the benefits of semantic search while minimizing the problems associated with applying existing semantic analysis at scale. Our approach avoids the need for complete semantic document markup using pre-existing ontologies by developing an automatically generated Concept-in-Context (CiC) network seeded by a priori analysis of Wikipedia texts and identification of semantic metadata. Our Capisco system analyzes documents by the semantics and context of their content. The disambiguation of search queries is done interactively, to fully utilize the domain knowledge of the scholar. Our method achieves a form of semantic-enhanced search that simultaneously exploits the proven scale benefits provided by lexical indexing.

year: 2015

title: !!!FR33D0M 0FF SP33CH!!!

authors: Smith, Hugh Lyal

subjects: Poetry

abstract: My title is “FR33D0M 0FF SP33CH”, a play on the saying “freedom of speech”. I write with the intent of voicing tough subjects that others haven’t or don’t, and often exposing things that I wouldn’t tell or share personally. “FR33D0M 0FF SP33CH” consists of 37 poems, 2 hooks and a chorus in this complete album. My earliest piece can date back to 2020 with the latest pieces being written in 2021. They express different visions of day-to-day life through points of view and alternating voices and perspectives. The topics range from anything like seeing a face in the smudge on a wall, to things like love, street styles and why I can’t sleep at night. They are to be read left to right, top to bottom -- but feel free to read them as you see fit, because it’s art after all and what you see is what you see. Those labelled “Mirrored” have been turned upside down to allow reading from either end and show the extent of form and variety my pieces can take. Some things may be explicit or hard to read, but I assure you that they are just certain views from different angles that I believe need to be shared. There is a strong political/cultural component to my mahi, a tough vocal attack on elements of society I believe are flawed and unjust, and an exposure of the addictions and abuses that colonial history and racial inequality lead to – but there’s also an intense celebration of the power of the Māori voice that remains, its beat and pride and resilience and ancestry, joined by a rich musical joy in the songs of the street I grew up in, their rhythms and rap, energy and power. It has taken me a long time to reach this level of writing in terms of technique, rhythm and content. I want the reader to see things through my shades and feel what it feels like to be me with an understanding of why I am and where I come from. To understand that, No, I don’t know everything, and I don’t expect anyone else to. But, Yes, this is what I saw, felt and how I interpreted it. So there it is and this is me, the bro Hugh. A lit ūrikā descendant of Ngāti Kuri, Ngāti Rēhia, Te Rārawa, Te Aupōuri and Ngāpuhi. Bred in the streets I-roam and made home. A dreamer of the future. Last but not least, your son, your brother, your bro and he who wrote the killer book that you are about to read. Churrr!!!

text: !!!FR33D0M 0FF SP33CH!!! My title is “FR33D0M 0FF SP33CH”, a play on the saying “freedom of speech”. I write with the intent of voicing tough subjects that others haven’t or don’t, and often exposing things that I wouldn’t tell or share personally. “FR33D0M 0FF SP33CH” consists of 37 poems, 2 hooks and a chorus in this complete album. My earliest piece can date back to 2020 with the latest pieces being written in 2021. They express different visions of day-to-day life through points of view and alternating voices and perspectives. The topics range from anything like seeing a face in the smudge on a wall, to things like love, street styles and why I can’t sleep at night. They are to be read left to right, top to bottom -- but feel free to read them as you see fit, because it’s art after all and what you see is what you see. Those labelled “Mirrored” have been turned upside down to allow reading from either end and show the extent of form and variety my pieces can take. Some things may be explicit or hard to read, but I assure you that they are just certain views from different angles that I believe need to be shared. There is a strong political/cultural component to my mahi, a tough vocal attack on elements of society I believe are flawed and unjust, and an exposure of the addictions and abuses that colonial history and racial inequality lead to – but there’s also an intense celebration of the power of the Māori voice that remains, its beat and pride and resilience and ancestry, joined by a rich musical joy in the songs of the street I grew up in, their rhythms and rap, energy and power. It has taken me a long time to reach this level of writing in terms of technique, rhythm and content. I want the reader to see things through my shades and feel what it feels like to be me with an understanding of why I am and where I come from. To understand that, No, I don’t know everything, and I don’t expect anyone else to. But, Yes, this is what I saw, felt and how I interpreted it. So there it is and this is me, the bro Hugh. A lit ūrikā descendant of Ngāti Kuri, Ngāti Rēhia, Te Rārawa, Te Aupōuri and Ngāpuhi. Bred in the streets I-roam and made home. A dreamer of the future. Last but not least, your son, your brother, your bro and he who wrote the killer book that you are about to read. Churrr!!!

year: 2021