title: Fragmentation pathways of [Re₂(μ-OR)₃(CO)₆]– (R = H, Me) and ligand exchange reactions with oxygen donor ligands, investigated by electrospray mass spectrometry

authors: Jiang, Chenghua

subjects: chemistry

abstract: The rhenium hydroxy and methoxy carbonyl complexes [Re₂(μOR)₃(CO)₆]⁻ (R = H or Me) have been studied by negative-ion electrospray mass spectrometry (ESMS). The complexes undergo facile exchange reactions with protic compounds, including alcohols and phenols. With dimethyl malonate, ester hydrolysis occurs giving carboxylate-containing complexes, and with H₂O₂ or ButOOH, oxidation to ReO₄⁻occurs. The feasibility and extent of these reactions can conveniently, rapidly, and unambiguously be determined by electrospray mass spectrometry, and is dependent on the acidity and steric bulk of the protic compound. The results also suggest that the complexes can be used as versatile starting materials for the synthesis of a wide range of analogous [Re₂(μ-OR)₃(CO)₆]⁻ complexes by simple reaction with an excess of the appropriate alcohol. By varying the applied cone voltage the fragmentation pathways have been investigated; the hydroxy complex undergoes dehydration followed by CO loss, whereas for the methoxy complex  -hydride elimination (and CO loss) is observed, with confirmation provided by deuterium labelling studies. Under ESMS conditions, the neutral complexes [Re₂(μ-OR)₂(μ-dppf )(CO)₆] [R = H or Me; dppf = 1,1 -bis(diphenylphosphino)ferrocene] undergo substantial solvolysis and hydrolysis to give mainly mononuclear species; simple parent ions (e.g. [M + H]⁺) are not formed in appreciable abundance, probably due to the lack of an efficient ionisation pathway.

text: Fragmentation pathways of [Re₂(μ-OR)₃(CO)₆]– (R = H, Me) and ligand exchange reactions with oxygen donor ligands, investigated by electrospray mass spectrometry The rhenium hydroxy and methoxy carbonyl complexes [Re₂(μOR)₃(CO)₆]⁻ (R = H or Me) have been studied by negative-ion electrospray mass spectrometry (ESMS). The complexes undergo facile exchange reactions with protic compounds, including alcohols and phenols. With dimethyl malonate, ester hydrolysis occurs giving carboxylate-containing complexes, and with H₂O₂ or ButOOH, oxidation to ReO₄⁻occurs. The feasibility and extent of these reactions can conveniently, rapidly, and unambiguously be determined by electrospray mass spectrometry, and is dependent on the acidity and steric bulk of the protic compound. The results also suggest that the complexes can be used as versatile starting materials for the synthesis of a wide range of analogous [Re₂(μ-OR)₃(CO)₆]⁻ complexes by simple reaction with an excess of the appropriate alcohol. By varying the applied cone voltage the fragmentation pathways have been investigated; the hydroxy complex undergoes dehydration followed by CO loss, whereas for the methoxy complex  -hydride elimination (and CO loss) is observed, with confirmation provided by deuterium labelling studies. Under ESMS conditions, the neutral complexes [Re₂(μ-OR)₂(μ-dppf )(CO)₆] [R = H or Me; dppf = 1,1 -bis(diphenylphosphino)ferrocene] undergo substantial solvolysis and hydrolysis to give mainly mononuclear species; simple parent ions (e.g. [M + H]⁺) are not formed in appreciable abundance, probably due to the lack of an efficient ionisation pathway.

year: 2000

title: Toward a theory of music information retrieval queries: System design implications

authors: Downie, J. Stephen

abstract: This paper analyzes a set of 161 music-related information requests posted to the rec.music.country.old-time newsgroup. These postings are categorized by the types of detail used to characterize the poster's information need, the type of music information requested, the intended use for the information, and additional social and contextual elements present in the
postings. The results of this analysis suggest that similar studies of 'native' music information requests can be used to inform the design of effective, usable music information retrieval
interfaces.

text: Toward a theory of music information retrieval queries: System design implications This paper analyzes a set of 161 music-related information requests posted to the rec.music.country.old-time newsgroup. These postings are categorized by the types of detail used to characterize the poster's information need, the type of music information requested, the intended use for the information, and additional social and contextual elements present in the
postings. The results of this analysis suggest that similar studies of 'native' music information requests can be used to inform the design of effective, usable music information retrieval
interfaces.

year: 2002-10-01

title: Reo Rua Pukapuka Pikitia: Whānau drawing on their community cultural wealth to create strategies for developing Te Reo Rangatira

authors: Brouwer, Jacqui

abstract: The use of Te Reo Māori in Early Childhood Education in Aotearoa New Zealand is mandated in the ECE curriculum. Research shows that picturebooks are powerful tools in language learning, but there is a lack of research concerning the use of bilingual picturebooks by whānau to support Māori language learning in a New Zealand kindergarten. This research presents findings from a 4-week programme in which five whānau members were introduced to several types of dual language picturebooks (Reo Rua Pukapuka Pikitia, RRPP) in a Puna Pukapuka Pikitia (PPP). Whānau explored RRPP and suggested how they could bring Reo Rangatira from RRPP into their homes to support language learning. Their suggestions aligned with Ellis’s principles of effective language teaching (Ellis, 2010) including the development of formulaic phrases, following the ways in which tamariki naturally learn language, encouraging opportunities for tamariki to speak and listen, as well as having interactions linked to RRPP.

text: Reo Rua Pukapuka Pikitia: Whānau drawing on their community cultural wealth to create strategies for developing Te Reo Rangatira The use of Te Reo Māori in Early Childhood Education in Aotearoa New Zealand is mandated in the ECE curriculum. Research shows that picturebooks are powerful tools in language learning, but there is a lack of research concerning the use of bilingual picturebooks by whānau to support Māori language learning in a New Zealand kindergarten. This research presents findings from a 4-week programme in which five whānau members were introduced to several types of dual language picturebooks (Reo Rua Pukapuka Pikitia, RRPP) in a Puna Pukapuka Pikitia (PPP). Whānau explored RRPP and suggested how they could bring Reo Rangatira from RRPP into their homes to support language learning. Their suggestions aligned with Ellis’s principles of effective language teaching (Ellis, 2010) including the development of formulaic phrases, following the ways in which tamariki naturally learn language, encouraging opportunities for tamariki to speak and listen, as well as having interactions linked to RRPP.

year: 2023