Photoswitchable molecular materials are of interest for optical data storage, optically controlled electronics, and light-controlled molecular machines or 'smart' surfaces. A promising way to incorporate optical switchability into materials is by using organic photochromic molecules--which convert reversibly between two forms with light--as ligands in coordination complexes. This design allows for the intimate communication between ligand and metal such that light-induced photoisomerization may be used to modulate metal-based properties. Spirooxazines, photochromic systems that photochemically isomerize between nonconjugated ring-closed spirooxazine (SO) and highly conjugated ring-opened photomerocyanine (PMC) forms, were derivatized with aphenanthroline moiety to enable the binding of transition-metal ions. Two phenanthroline-spirooxazines, an indolyl derivative and an azahomoadamantyl derivative, were investigated in the context of chemical substitution and medium effects. The ring-opened PMC forms of the spirooxazines were characterized by solid- and/or solution-state methods to extract the relative contributions of the canonical quinoidal and zwitterionic resonance forms to their molecular structure. The PMC form of the azahomoadamantyl derivative was found to exhibit significant zwitterionic character, with demonstrated sensitivity to medium polarity. The pronounced zwitterionic character was correlated with the high stability of the PMC form, high photoresponsivity, and slow thermal relaxation rates in this class of spirooxazines. The relative ligand field strengths of the SO and PMC forms of the two phenanthroline-spirooxazines were analyzed using the FT-IR and 13C NMR carbonyl signals of their molybdenum-tetracarbonyl-spirooxazine complexes. Differences in metal-ligand bonding in the SO and PMC forms were also investigated by a density functional theory fragment molecular orbital analysis. The SO form was found to be a better n-acceptor both empirically and theoretically. Lastly, the spirooxazine ligands were incorporated into electronically bistable cobalt-dioxolene redox isomers, where the low-spin-CoIII/high-spin-CoII equilibrium is sensitive to ligand field strength. Using solution-state spectroscopic methods, it was shown that the redox state of the cobalt centre could be modulated through photoisomerization of the spirooxazine ligand. As changes in cobalt redox state are associated with changes in magnetic spin state, this system forms the basis for a room-temperature photomagnetic material and highlights the powerful role of photochromic phenanthroline-spirooxazineligands in developing photoswitchable multifunctional materials.

Summarizing all the latest trends and recent topics in one handy volume, this book covers everything needed for a solid understanding of photochromic materials. Following a general introduction to organic photochromic materials, the authors move on to discuss not only the underlying theory but also the properties of such materials. After a selection of pplications, they look at the latest achievements in traditional solution-phase applications, including photochromic-based molecular logic operations and memory, optically modulated supramolecular system and sensors, as well as light-tunable chemical reactions. The book then describes the hotspot areas of photo-switchable surfaces and nanomaterials, photochromic-based luminescence/electronic devices and bulk materials together with light-regulated biological and bio-chemical systems. The authors conclude with a focus on current industrial applications and the future outlook for these materials. Written with both senior researchers and entrants to the field in mind.

This dissertation, "Design, Synthesis and Studies of Novel Classes of Photochromic Spirooxazine and Diarylethene Ligands and Their Metal-to-ligand Charge Transfer Complexes" by Chi-chiu, Ko, 高志釗, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b4389531 Subjects: Metal complexes - Synthesis Photochromism Ligands Ruthenium compounds - Synthesis

This book highlights the synthesis, luminescence, and applications of rare earth-doped phosphors materials for solid-state lighting. Solid-state lighting is turning into a leading technology in the lighting industry, permitting improvement in the fields from architectural to domestic applications. Driven with the aid of using ongoing multi-field research, solid-state lighting needs an improvement of various technologies: efficient and reliable light-emitting devices, devices for new functionalities, and optical solutions for beam shaping. Noteworthy research endeavors were aimed to find out eco-friendly, better performance, cost, and energy-efficient phosphor materials for the application in solid-state lighting devices. Power phosphor materials with advanced optical and photoluminescence properties in a wide range of areas have shared the research efforts in this sector aimed in the direction of achieving better material features. Rare earth ion-doped phosphor materials have been the subject of scientific interest because of their significant applications in a variety of fields such as display devices, temperature sensors, solar cells, bio-imaging, and optoelectronics devices. This book covers the broad aspects of organic and inorganic materials based on phosphor materials and is beneficial to researchers involved in these areas. This book is specially designed to provide an introductory concept of luminescent materials, particularly man-made (artificial) phosphors in a language comprehensible to beginners and students. The book also includes some new materials with promising technologies and upgraded properties that expose new potential possibilities are also highlighted.

This book focuses on photoswitches. The objective of the book is to introduce researchers and graduate course students who are interested in "photon-working switches" not only to the fundamentals but also to the latest research being carried out in this field. Light can reach a target substrate without any physical contact to deliver energy. The energy can induce changes in the structure of the molecules included in the substrate so that its properties and functions are made switchable by light irradiation. When a substrate is able to revert to its original state, this system can be regarded as a "photon-working switch". The terms "photon-working switches" or "photoswitches" are almost equivalent in meaning to "photochromism"; however, they focus on the "switching of functions" of chemical species rather than their "reversible transformation". Most of the authors of this volume are members of PHENICS, an international research group on organic molecular photoswitches composed of research institutions from France, Japan, Russia, China and Germany. Since its inception in 2008, PHENICS has promoted active research to develop the field. This book commemorates the group's eighth year of collaborative research.

Photochromism is simply defined as the light induced reversible change of colour. The field has developed rapidly during the past decade as a result of attempts to improve the established materials and to discover new devices for applications.As photochromism bridges molecular, supramolecular and solid state chemistry, as well as organic, inorganic and physical chemistry, such a treatment requires a multidisciplinary approach and a broad presentation. The first edition (1990) provided an enormous amount of new concepts and data, such as the presentation of main families based on the pericyclic reaction mechanism, the review of new families, some bimolecular photocycloadditions and some promising systems. This new edition provides an efficient entry into this flourishing field, with the core content retained from the original work to provide a basic introduction into the different subjects. *Second edition of a work first published in 1990, now revised due to constant development of research. *Including updated lists of references (1989-2001), offering immediate access to recent developments.*Providing great basic interest and high application potential bringing scientists together from chemistry, physics and engineering.