Photoisomerization of (2-cyanoethyl)(isonicotinic acid)cobaloxime complex in a series of isostructural host–guest complex crystals

Hashizume, Daisuke; Ohashi, Yuji

doi:10.1039/a902900a

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…In some cobaloxime complexes, one of Ohashi's most featured series of compounds, the nature of reaction cavities has been further probed by photoismerism studies of cobaloxime complexes as guests within a series of cyclohexylamine hosts. 31 Coppens and co-workers have also been synthesising host-guest complexes where the guest is a photo-active species. There, the primary interest is in finding a suitable method to 'dilute' the photoactive species so that the crystal lattice is stabilised even in the case of large structural changes 32 so that one can augment the maximum percentage of excitation possible above which crystal fracture occurs.…”

Section: Structural Results Obtained So Farmentioning

confidence: 99%

Single-crystal X-ray diffraction studies of photo-induced molecular species

Cole

2004

Chem. Soc. Rev.

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This tutorial review gathers together the recent developments in single-crystal X-ray diffraction that are starting to enable one to quantify directly the nature of light-induced electronic perturbations in chemical structures. Such structural information is key to understanding many photo-activated chemical processes and physical properties, and a description of the scientific impetus behind this incipient area of structural science, from academic and industrial perspectives, is given. Photoisomerism processes, solid-state photochemical reactions and spin-cross-over magnetic transitions, that have long-lived or irreversible light-induced states, are best understood by unravelling their three-dimensional structures measured in situ in their photo-converted state. A review of steady-state laser-induced single-crystal X-ray diffraction studies conducted, to date, and the experimental methodologies used in order to realise such structures, is presented. The structural characterisation of more transient photo-induced species (down to picosecond lifetimes) is paramount to a better understanding of the materials that undergo high-speed electronic switching, which make operative much of the electronics and optics industry, since there exists an inherent relationship between the excited-state structure and the physical properties exhibited. Prime examples include excited-state structures of molecular conductors and luminescent materials with potential applications as molecular wires, light-emitting diodes, non-linear optics, triboluminescence and electroluminescence. Previously, only indirect and qualitative interpretations of the nature of these excited-states could be formulated via spectroscopic techniques, but the developments in ms-ps time-resolved laser pump, X-ray probe single-crystal diffraction techniques, described herein, are overcoming this barrier, affording results that are entirely quantitative via a three-dimensional structural representation. In this regard, a review of structures of transient species studied to date is presented along with a discussion of the key experimental parameters that are required for a successful experiment, in terms of the X-ray, laser and sample characteristics. The importance of auxiliary spectroscopic work and complementary theoretical calculations is also briefly discussed. The paper concludes with a future outlook on new possible X-ray sources that will facilitate such work and extend it to structural studies on even more ephemeral species in the future.

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Section: Structural Results Obtained So Farmentioning

confidence: 99%

Single-crystal X-ray diffraction studies of photo-induced molecular species

Cole

2004

Chem. Soc. Rev.

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“…Reaction cavities for 2-ce groups of A and B molecules before irradiation. Reproduced from Hashizume and Ohashi [141] with permission from The Royal Society of Chemistry.…”

Section: Crystallography Reviews 117mentioning

confidence: 98%

“…Based on the above conditions, the cobaloxime complex with isonicotinic acid as an axial ligand and secondary amines with aromatic rings as hosts were examined as acidbase complexes, as shown in Scheme 17 [139][140][141]. Hereafter, the crystals of the …”

Section: Crystallography Reviews 113mentioning

confidence: 99%

Dynamic motion and various reaction paths of cobaloxime complexes in crystalline-state photoreaction

Ohashi¹

2013

Crystallography Reviews

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The various alkyl groups bonded to the cobalt atom in (alkyl)(base)cobaloxime complex crystals are isomerized on exposure to visible light without degradation of the single crystal form. The solid-state reactions keeping the single crystal form were called crystalline-state reactions and the reaction mechanisms were explained with the concept of reaction cavity for the alkyl group. Changing the axial base ligands, a variety of crystalline-state reactions were examined not only by X-rays but also by neutron diffraction. The various reaction paths were made clear from the structures of initial, intermediate and final stages of the reactions. Moreover, the reaction rate was proved to have a positive relation with the volume of reaction cavity in each reaction. Not only various isomerizations but also unusual racemic-to-chiral transformations and a chirality inversion were also observed and the mechanisms were clearly explained and the shape of the reaction cavity made clear the mechanism. Two promising methods to observe the photoreaction with retention of the single crystal form, mixed crystal formation and bulky group insertion, are proposed and several successful results are shown.

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“…In some cobaloxime complexes, for example, among Ohashi's featured compounds, the nature of reaction cavities has been probed by photoisomerization of cobaloxime complexes as guests within cyclohexylamine hosts (Hashizume & Ohashi, 1999).…”

Section: Results Obtained So Farmentioning

confidence: 99%

Photocrystallography

Cole

2007

Acta Cryst Sect A

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This review describes the development and application of a new crystallographic technique that is starting to enable the three-dimensional structural determination of molecules in their photo-activated states. So called 'photocrystallography' has wide applicability, particularly in the currently exciting area of photonics, and a discussion of this applied potential is put into context in this article. Studies are classified into four groups: photo-structural changes that are (i) irreversible; (ii) long-lived but reversible under certain conditions; (iii) transient with photo-active lifetimes of the order of microseconds; (iv) very short lived, existing at the nanosecond or even picosecond level. As photostructural changes relative to the 'ground state' can be subtle, this article necessarily concentrates on small-molecule single-crystal X-ray diffraction given that high atomic resolution is possible. That said, where it is pertinent, references are also made to related major advances in photo-induced macromolecular crystallography. The review concludes with an outlook on this new research area, including the future possibility of studying even more ephemeral, femtosecond-lived, photo-active species.

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Photoisomerization of (2-cyanoethyl)(isonicotinic acid)cobaloxime complex in a series of isostructural host–guest complex crystals

Cited by 8 publications

References 21 publications

Single-crystal X-ray diffraction studies of photo-induced molecular species

Single-crystal X-ray diffraction studies of photo-induced molecular species

Dynamic motion and various reaction paths of cobaloxime complexes in crystalline-state photoreaction

Photocrystallography

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