There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

This paper provides a third update to the review of reversible deactivation radical polymerization (RDRP) achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition-fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669) and the second in December 2009 (Aust. J. Chem. 2009, 62, 1402). This review cites over 700 publications that appeared during the period mid 2009 to early 2012 covering various aspects of RAFT polymerization which include reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses, and a diverse range of applications. This period has witnessed further significant developments, particularly in the areas of novel RAFT agents, techniques for end-group transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.

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Living Radical Polymerization by the RAFT Process - A Second Update

Radical addition-fragmentation chemistry in polymer synthesis

Photochromic organic–inorganic hybrid materials have attracted considerable attention owing to their potential application in photoactive devices, such as optical memories, windows, photochromic decorations, optical switches, filters or non-linear optics materials. The growing interest in this field has largely expanded the use of photochromic materials for the purpose of improving existing materials and exploring new photochromic hybrid systems. This tutorial review summarizes the design and preparation of photochromic hybrid materials, and particularly those based on the incorporation of organic molecules in organic–inorganic matrices by the sol–gel method. This is the most commonly used method for the preparation of these materials as it allows vitreous hybrid materials to be obtained at low temperatures, and controls the interaction between the organic molecule and its embedding matrix, and hence allows tailoring of the performance of the resulting devices.

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Photochromic organic-inorganic hybrid materials.

This work was supported by the Foundation for Science and Technology (FCT), Portugal (projects PTDC/QUI-QUI/113687/2009 and PEst-C/QUI/UI0081/2013). A.G. (SFRH/BD/43531/2008) and M.J.M. (SFRH/BD/61262/2009) thank FCT for grants.

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Chromone: A Valid Scaffold in Medicinal Chemistry

The density functional theory and time-dependent density functional theory calculations of the electronic structures and electronic absorption spectra of a series of zinc porphyrin based sensitizers were reported. The sensitizers comprise of either 10H-phenothiazin-3-yl or bis(4-(hexyloxy)phenyl)amino and acene bridged carboxylic acid as electron donating and accepting units, respectively. The dye–(TiO2)36 anatase nanoparticle systems were also simulated to show the electronic structure on the interface. The calculated results show that a strong electron-donating capacity of the donor group attached at the meso-position opposite to the anchoring group of the dye will increase the molecular extinction coefficient, excited state lifetime, light harvesting efficiency and decrease the reorganization energy as compared to the structurally similar reference dye YD2-o-C8. The calculated short circuit current density and level alignment quality clearly indicate that the zinc-porphyrin dyes substituted with 10H-phenothiazin-3-yl donor and either 4-ethynylbenzoic acid or 4-ethynyl-1-naphthoic acid offer potential for use in DSSCs due to their large values when compared to the reference dye. The results obtained in this study will certainly provide a useful reference to the future design of tetra-substituted zinc porphyrins for dye sensitized solar cell applications.

Theoretical study on the light harvesting efficiency of zinc porphyrin sensitizers for DSSCs

Negatively photochromic organic compounds: Exploring the dark side

Observations on the Synthesis of Photochromic Naphthopyrans

A range of polymerisable photochromic naphthopyrans were prepared via the synthesis of an acrylate moiety on either the naphthalene ring (R) and/or the di-aryl (Ar) rings on the 3-position of the naphthopyran. The monomers obtained (NA) were copolymerised with methyl methacrylate (MMA) and methyl acrylate (MA) by the RAFT (reversible addition fragmentation chain transfer) process in order to control the structure of the polymeric chains and accurately control the number of photochromic molecules per chain. Films were prepared with the synthesized photochromic polymers and their photochromic properties were assessed. We found that the fading rate of the photochromic dye was slower in a matrix of PMMA (higher Tg) than in a matrix of PMA (lower Tg). By producing block copolymers of PMMA-b-poly(MA-co-NA), the fading rate was increased, and the production of PS-b-poly(MA-co-NA) further enhanced the speed of switching, as phase separation occurred between the poly(MA-co-NA) block and the PS block. This study presents an example of tuning the photochromic properties of a dye via variation of the architecture of its polymeric support.

B. Mark Heron

Papers

Theoretical study on the light harvesting efficiency of zinc porphyrin sensitizers for DSSCs

Negatively photochromic organic compounds: Exploring the dark side

Observations on the Synthesis of Photochromic Naphthopyrans

Tuning the color switching of naphthopyrans via the control of polymeric architectures

Pyrans and their Benzo Derivatives - Synthesis