title: Theoretical study of the structures of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide and tris(pentafluorophenyl)phosphine oxide: Why does the crystal structure of (tetrafluoropyridyl)diphenylphosphine oxide have two different P=O bond lengths?

authors: Lane, Joseph R.

subjects: Science & Technology

abstract: The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (1) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (2) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of 1, which comprises lone pair–π, weak hydrogen bonding and C–H···arene interactions, has energies of 70 and 71 kJ mol⁻¹. The attraction between molecules of 2 comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol−1. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of 1. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for 2, and so there is no difference between the P=O distances of 2.

text: Theoretical study of the structures of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide and tris(pentafluorophenyl)phosphine oxide: Why does the crystal structure of (tetrafluoropyridyl)diphenylphosphine oxide have two different P=O bond lengths? The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (1) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (2) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of 1, which comprises lone pair–π, weak hydrogen bonding and C–H···arene interactions, has energies of 70 and 71 kJ mol⁻¹. The attraction between molecules of 2 comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol−1. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of 1. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for 2, and so there is no difference between the P=O distances of 2.

year: 2020

title: Policy solutions to social housing stigmatisation in Aotearoa

authors: Southey, Kim

abstract: This policy brief discusses social housing stigmatisation as a process and experience that has detrimental effects on social housing tenants. The brief also highlights the role social housing policy must play in addressing stigmatisation, thereby, ensuring the wellbeing and community inclusion of social housing residents. The discussion and recommendations in this brief are based on a review of evidence for the WERO (Working to End Racial Oppression) research project, examining how neighbours’ perceptions as well as policies and practices of social housing provision impact social housing tenants’ experiences of wellbeing and neighbourhood inclusion.

text: Policy solutions to social housing stigmatisation in Aotearoa This policy brief discusses social housing stigmatisation as a process and experience that has detrimental effects on social housing tenants. The brief also highlights the role social housing policy must play in addressing stigmatisation, thereby, ensuring the wellbeing and community inclusion of social housing residents. The discussion and recommendations in this brief are based on a review of evidence for the WERO (Working to End Racial Oppression) research project, examining how neighbours’ perceptions as well as policies and practices of social housing provision impact social housing tenants’ experiences of wellbeing and neighbourhood inclusion.

year: 2025-02

title: He Whakaoranga Kia Puta Kia Ora (prepared for Health Research Council of New Zealand)

authors: Kilgour, Jonathan T.

abstract: This research project explored the relationship between cultural connectedness and wellbeing (as a social determinant of health). In particular, the research explored the diverse ways in which tribal members connected with and expressed their Waikatotanga.

text: He Whakaoranga Kia Puta Kia Ora (prepared for Health Research Council of New Zealand) This research project explored the relationship between cultural connectedness and wellbeing (as a social determinant of health). In particular, the research explored the diverse ways in which tribal members connected with and expressed their Waikatotanga.

year: 2015