title: The reactivity of [Pt₂(μ-S)₂(PPh₃)₄] towards difunctional chloroacetamide alkylating agents: Formation of cyclized or bridged products

authors: Ujam, Oguejiofo Theophilus

subjects: platinum complexes

abstract: The reactions of [Pt₂(μ-S)₂(PPh₃)₄] towards some bis(chloroacetamide) alkylating agents have been investigated. Reaction with one mole equivalent of the hydrazine-derived compound ClCH₂C(O)NHNHC(O)CH₂Cl led to the cyclized product [Pt₂{SCH₂C(O)NHNHC(O)CH₂S}(PPh₃)₄]²⁺ which showed two different PPh₃ environments in the ³¹P{1H} NMR spectrum, as a result of non-fluxional behavior of the dithiolate ligand in solution. Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with the ortho and para isomers of the phenylenediamine-derived bis(chloroacetamides) ClCH2C(O)NHC6H4NHC(O)CH2Cl gave tetrametallic complexes containing two {Pt₂S₂} moieties spanned by the CH₂C(O)NHC₆H₄NHC(O)CH₂ group. Both the ortho and para isomers were crystallographically characterized; in the ortho isomer there is intramolecular CO=H–N and S•••H–N hydrogen bonding involving the two amide groups.

text: The reactivity of [Pt₂(μ-S)₂(PPh₃)₄] towards difunctional chloroacetamide alkylating agents: Formation of cyclized or bridged products The reactions of [Pt₂(μ-S)₂(PPh₃)₄] towards some bis(chloroacetamide) alkylating agents have been investigated. Reaction with one mole equivalent of the hydrazine-derived compound ClCH₂C(O)NHNHC(O)CH₂Cl led to the cyclized product [Pt₂{SCH₂C(O)NHNHC(O)CH₂S}(PPh₃)₄]²⁺ which showed two different PPh₃ environments in the ³¹P{1H} NMR spectrum, as a result of non-fluxional behavior of the dithiolate ligand in solution. Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with the ortho and para isomers of the phenylenediamine-derived bis(chloroacetamides) ClCH2C(O)NHC6H4NHC(O)CH2Cl gave tetrametallic complexes containing two {Pt₂S₂} moieties spanned by the CH₂C(O)NHC₆H₄NHC(O)CH₂ group. Both the ortho and para isomers were crystallographically characterized; in the ortho isomer there is intramolecular CO=H–N and S•••H–N hydrogen bonding involving the two amide groups.

year: 2011

title: Development and Characterisation of Plasmonic Devices for Sensing Applications

authors: Sedoglavich, Nemanya

subjects: Plasmonic

abstract: In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

text: Development and Characterisation of Plasmonic Devices for Sensing Applications In recent years, discoveries and advances that utilise nano-scale (10^-9m) structures and associated phenomena have led to a number of entirely new areas of research in the fields of physics, chemistry, biology, and materials science. The photonic field of plasmonics is the study of light interaction with nanometer-scaled metal-dielectric features, which gives rise to a variety of phenomena, including surface plasmon resonance, localised surface plasmon resonance, and metal enhanced fluorescence. The focus of this thesis is on the development and characterisation of nanophotonic devices, which utilise plasmonic phenomena and have potential for sensor applications.
During the course of this research a surface plasmon resonance analysis platform was devised, which utilises the gold grating of commercially available compact disks as the sensing substrate. This measurement method offers a high resolution refractive index analysis of gases and surface chemistry and is capable of analysing a large number of samples by scanning over the entire disk surface. The system implements a method of phase-polarisation contrast to improve the sensing performance. It enhances signal detection through redistributing the residual p-polarised waves, which have been strongly absorbed by the surface plasmon resonance substrate/sensor. This effectively lowers the reflected light intensity at the surface plasmon resonance minimum. The scheme results in the deepening of the intensity minimum to below 3.5% reflection and the enhancement of resonance to non-resonance contrast by up to 14 times, and thereby increasing sensitivity.
A range of new nanophotonic structures have been modelled, developed, fabricated, and characterised, which we call wavelength and polarisation selective polariton generators (SPGs). These polarisation-sensitive structures combine a tuneable plasmon resonator and a subwavelength aperture to selectively generate and transmit polaritons of a desired wavelength through a central nanohole. Individual SPGs permit modulation of transmission intensity, with calculated enhanced optical transmission (ratio of output to input flux) of up to 10 and up to 4-fold measured amplitude modulation. The paired SPGs gave rise to multiple spectrally discrete transmission peaks which, when modulated, provide a multi-state operation in a single device. The measured amplitude modulation was up to 10-fold. For the linearly continuous SPG, by controlling the polarisation as a tuning variable, it selectively generated and transported polaritons of a desired wavelength. It exhibited a spectral shift of 40 nm over the full range of polarisation angles. The modelled enhanced optical transmission was calculated to be up to 17.2. An instrument was developed for measuring and characterising light transmission through single nanoholes, nanohole arrays, and other complex structures. The operational characteristics of these elements show close agreement between model predictions and experimental data. It also demonstrates new designs of plasmonic structures which utilise selective behaviour based on the polarisation of incident light.

year: 2009

title: Curriculum integration as treaty praxis.

authors: Fraser, Deborah

subjects: curricula

abstract: The article discusses the significance of curriculum integration on the promotion of principles of the Treaty of Waitangi, an agreement signed in 1840 by the Maori and the Crown people in New Zealand. It explores the challenges linked with this curriculum theory design. It also highlights a case study which analyzes the impact of curriculum integration in education.

text: Curriculum integration as treaty praxis. The article discusses the significance of curriculum integration on the promotion of principles of the Treaty of Waitangi, an agreement signed in 1840 by the Maori and the Crown people in New Zealand. It explores the challenges linked with this curriculum theory design. It also highlights a case study which analyzes the impact of curriculum integration in education.

year: 2002