A new luminescent Ru(terpy) complex incorporating a 1,2,4-triazole based σ-donor ligand

The mononuclear compound [Ru(terpy)L], where H2L is 2,6-bis(1,2,4-triazol-3-yl)pyridine, shows an emission lifetime of 65 ns, about 300 times longer than that observed for the parent [Ru(terpy)3]2+ complex

Ruthenium (II) complexes with terpyridine derivatives: what is the lifetime of the excited state dependent on?

The synthesis, spectroscopic and electrochemical characterisation of ruthenium (II) polypyridyl mononuclear complexes containing 1,2,4-tnazole and tetrazole moiety are described. Chapter one is an introduction relating to the work described in the thesis. The methods of characterisation, which are described in chapter two, include High Performance Liquid Chromatography, 'H-NMR, UV/Visible spectroscopy, fluorimetry, electrochemistry, spectroelectrochemistry, mass spectrometry, and lifetime emission measurements. Chapter three describes the synthesis of the new set of ligands and their mononuclear Ruthenium (II) complexes. Chapter four contains an extensive characterisation of Ru(II)(bpy)2 moiety complexes containing a 5-(2-pyridyl)-l,2,4-triazole ligand, (Apy), or a 5-(2-pyridyl) tetrazole ligand, ([ ipy), and their comparison with the archetype Ru(bpy)s2+. The examination of the acid-base chemistry of the complexes by UV/Visible spectroscopy revealed important information about the location of the excited state. Chapter five explores the spectroscopic, photophysical and electrochemical properties of the new [Ru(tpy)fApyA)] complexes, where (ApyA)2' is the 2,6 di-(l,2,4- triaz-3-yl)-pyridine ligand. The new species was exhaustively studied especially because it revealed to be one of the few example, available in literature, of emitting Ru(H) terpiridine complexes, with a lifetime of the excited state in the order of 100 nanoseconds. Chapter six describes the synthesis of complexes containing (ApyA)2' and terpyridine derivatives or vice-versa terpyridine and (ApyA)2" derivative ligands. One of them will be used as a photsensitiser in a photovoltaic cell. Attachment of the [Ru(II)(tctpy)(ApyA)] complex to nanocrystalline TiC>2 films indicates incident photonto- current efficiency (IPCE) of greater than 60%. Chapter seven exptores the use of a new 2,6 di-(tetraz-5-yl)-pyndine ligand, (Upyl ]) ", and the spectroscopic, photophysical and electrochemical properties of its Ru(II) complexes. Chapter eight is an attempt to rationalise the collected data of the Ru(tpy) moiety. The change of the energy levels in relation to the different ligands is analysed. The correlations between spectroscopic, photophysical and electrochemical data of the new complexes and the existent ones created an extensive knowledge of the tridentate Ru(H) complexes, that increases their availability as a photosensitive building block for a supramolecular system. Some suggestions for future work are also considered in the final Chapter. Finally two appendices are included in this thesis. The first is a literature survey which synopsises the last ten years scientific papers, on the Ru-tpy moiety, includmg investigations of their properties, use in analytical research or their use as building blocks in supramolecolar systems. The second appendix refers to the publications, poster presentations and oral presentations made during the course of the research

THE INFLUENCE OF GRATITUDE ON LEARNING ENGAGEMENT AMONG UNDERGRADUATE STUDENTS

This study aimed to examine the influence of gratitude on learning engagement among undergraduate students at University Malaysia Sarawak (UNIMAS), Kota Samarahan, Sarawak. There are 112 data have been collected from students in different faculties. The instrument of this study can be used because it has been proven valid and reliable. This study has found that the influence of gratitude on learning among undergraduate students at UNIMAS is at a low level and cognitive engagement is the majority of learning engagement at UNIMAS. This study showed no significant difference in gratitude towards student learning engagement among undergraduate students at University Malaysia Sarawak (UNIMAS). Moreover, this study also discovered that there is a positive correlation between gratitude and student engagement, where the influence of gratitude has a positive impact on encouraging students to be actively engaged in their learning. Based on the analysis of the findings, it proved that the influence of gratitude is parallel to the involvement of learning, whereby if the students have high feelings of gratitude, their learning engagement also increases. To improve and enhance this study, future researchers are advised to conduct this research by covering the factors involved in stimulating students’ express gratitude for their learning and its relevance to the three aspects of learning engagement

Synthesis and characterisation of ruthenium complexes containing a pendent catechol ring

A series of [Ru(bipy)₂L]⁺ and [Ru(phen)₂L]⁺ complexes where L is 2-[5-(3,4-dimethoxyphenyl)-4H-1,2,4-triazol-3-yl]pyridine (HL1) and 4-(5-pyridin-2-yl-4H-1,2,4-triazol-3-yl)benzene-1,2-diol (HL2) are reported. The compounds obtained have been characterised using X-ray crystallography, NMR, UV/Vis and emission spectroscopies. Partial deuteriation is used to determine the nature of the emitting state and to simplify the NMR spectra. The acid-base properties of the compounds are also investigated. The electronic structures of [Ru(bipy)₂L1]⁺ and Ru(bipy)₂HL1]²⁺ are examined using ZINDO. Electro and spectroelectrochemical studies on [Ru(bipy)₂(L2)]⁺ suggest that proton transfer between the catechol and triazole moieties on L2 takes place upon oxidation of the L2 ligand

Luminescent anion recognition: Probing the interaction between dihydrogenphosphate anions and Ru(II) polypyridyl complexes in organic and aqueous media.

A photophysical study of the interaction between dihydrogen phosphate anions and a series of ruthenium polypyridyl complexes containing anion receptor 4,4'-bis[(2-methoxyethyl)carbamoyl]-2,2'-bipyridine (L1) is reported. The complexes investigated are of the type [Ru(L)[2](L1)]X[2] and [Ru(L1)[3]]X[2], where L is 2,2'-bipyridyl or 1,10-phenanthroline and X is chloride or PF[6]-. The emission properties of the compounds are studied as a function of the anion concentrations using emission lifetime and steady-state measurements. For the mixed ligand complexes the emission intensity and lifetime increases upon the addition of 2.5 molar equivalents of H[2]PO[4]-, further additions do not result in further increases. For [Ru(L1)[3]]X[2] the emission increases upon addition of the first 2.5 equivalents of dihydrogen phosphate, however, further increases lead to a decrease in both emission intensity and lifetime. The effect of the addition of trace amounts of water is also examined

A new luminescent Ru(terpy) complex incorporating a 1,2,4-triazole based σ-donor ligand

The mononuclear compound [Ru(terpy)L], where H2L is 2,6-bis(1,2,4-triazol-3-yl)pyridine, shows an emission lifetime of 65 ns, about 300 times longer than that observed for the parent [Ru(terpy)3]2+ complex

The Blueprint of AWOS Implementation for Aviation Services at BMKG

Weather is very critical for aviation. Especially regarding safety in air transportation. Badan Meteorologi, Klimatologi, dan Geofisika (BMKG) in its duties and functions provides aviation weather information, conducts the latest weather observation activities for the needs of takeoff and landing at airports. The World Meteorological Organization (WMO) has targeted automation with a target achievement in 2017. But currently in conducting the latest weather observations, BMKG still uses conventional weather observation systems even though at some airports Automated Weather Observing Systems (AWOS) have been installed. The automated weather observing system is still not fully implemented yet. This study aims to create a blueprint for the implementation of automatic weather observations for aviation services within the BMKG. Guidelines for making blueprint use the Enterprise Architecture Planning (EAP) framework. EAP defines business and architectural needs related to data, applications, and technology needed to implement automation. The final results achieved are in the form of a blueprint for the implementation of automated weather observing system for aviation services within the BMKG which can be a guide for BMKG in achieving the vision related to aviation weather services

Gating Current flowing through Molecules in Metal-Molecules-Metal Junctions

We have assembled two junctions that incorporate redox sites between Hg electrodes by different interactions. In the first junction, Hg-SAM-R//R-SAM-Hg, the redox site (R) are covalently linked to each electrode in self assembled monolayers (SAM-R). In the second junction, Hg-SAM//R//SAM-Hg, the redox sites dissolved in solution are trapped by electrostatic interaction at the SAM formed at the electrodes. The current flowing through these junctions can be controlled by adjusting the potential applied at the electrodes respect to the redox potential of the species by using an electrochemical system. The current flowing in these two junctions is mediated by the redox sites through different mechanisms. In particular, the current flowing through junction Hg-SAM-R//R-SAM-Hg occurs through a self exchange mechanism between the redox sites organized at each electrode, while the current flowing through junction Hg-SAM//R//SAM-Hg is dominated by a redox- cycling mechanism. The systems described here are easy to assemble, well-characterized, yield reproducible data and make it easy to modify the electrical properties of the junctions by changing the nature of the redox centres. For these characteristics they are well suited for collecting fundamental information relevant to the fabrication of molecular switches