The Photoarrangement of α-Santonin is a Single-Crystal-to-Single-Crystal Reaction:  A Long Kept Secret in Solid-State Organic Chemistry Revealed

Natarajan, Arunkumar; Tsai, C. K.; Khan, Saeed I.; McCarren, Patrick; Houk, K. N.; Garcı́a-Garibay, Miguel A.

doi:10.1021/ja073189o

Cited by 103 publications

(77 citation statements)

References 11 publications

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“…This observation of crystal motility was to become the first documented report of the thermosalient (TS) effect (Hüpf-Effekt)-the propensity of certain crystals to hop and leap when heated over a phase transition 9,10,18,19 . Two polymorphs, yellow form (a) and red form (b), were characterized 17 .…”

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confidence: 89%

Colossal positive and negative thermal expansion and thermosalient effect in a pentamorphic organometallic martensite

et al. 2014

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The thermosalient effect is an extremely rare propensity of certain crystalline solids for self-actuation by elastic deformation or by a ballistic event. Here we present direct evidence for the driving force behind this impressive crystal motility. Crystals of a prototypical thermosalient material, (phenylazophenyl)palladium hexafluoroacetylacetonate, can switch between five crystal structures (a-e) that are related by four phase transitions including one thermosalient transition (a2g). The mechanical effect is driven by a uniaxial negative expansion that is compensated by unusually large positive axial expansion (260 Â 10 -6 K -1 ) with volumetric expansion coefficients (E250 Â 10 -6 K -1 ) that are among the highest values reported in molecular solids thus far. The habit plane advances at B10 4 times the rate observed with non-thermosalient transitions. This rapid expansion of the crystal following the phase switching is the driving force for occurrence of the thermosalient effect.

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mentioning

confidence: 89%

Colossal positive and negative thermal expansion and thermosalient effect in a pentamorphic organometallic martensite

et al. 2014

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“…[5,6] Photochromic materials have received considerable attention for their potential applications in information display devices, high-density memory, and other high-tech areas. While purely organic [7] or inorganic [8] photochromic materials have been known for a long time, much attention has recently been dedicated to the development of photochromic inorganic-organic hybrids because of the novel and intriguing properties arising from the interactions between both organic and inorganic components. Structurally well-defined hybrids will give us better insight into these interactions.…”

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confidence: 99%

Wavelength‐Dependent Photochromic Inorganic–Organic Hybrid Based on a 3D Iodoplumbate Open‐Framework Material

et al. 2008

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Organically templated inorganic open-framework materials have been fueled by intriguing architectures and topologies as well as fascinating physical properties. [1,2] These materials can be structurally classified into two subclasses: [1,3] the zeotype materials, in which all polyhedra of the wall are exclusively tetrahedral, and the frameworks built from mixed polyhedra.However, 3D open-framework materials constructed from purely octahedral units have not been obtained so far for these materials, although these have been observed in a few metal-organic frameworks [4] and purely inorganic materials. [5,6] Photochromic materials have received considerable attention for their potential applications in information display devices, high-density memory, and other high-tech areas. While purely organic [7] or inorganic [8] photochromic materials have been known for a long time, much attention has recently been dedicated to the development of photochromic inorganic-organic hybrids because of the novel and intriguing properties arising from the interactions between both organic and inorganic components. Structurally well-defined hybrids will give us better insight into these interactions. However, few hybrids based on transition-metal oxides and polyoxometalates have been explored with simultaneous characterization of their structure and photochromism.[9] Less attention has been paid to the photochromic hybrids based on metal halide semiconductors, [10] although the charge transfer between organic and inorganic components has been observed in these systems. [11] We obtained a yellow prismatic hybrid crystal (EDAMP) 2n (Pb 7 I 18 ) n ·4 n H 2 O (1; EDAMP = Et 2 NHC 6 H 4 -CH 2 C 6 H 4 NHEt 2 ) through a synchronous process of in situ N-alkylation and assembly under solvothermal conditions. This material represents a new subclass of 3D inorganic openframework materials built from purely octahedral units and behaves as a quantum-wire array. More interestingly, the compound shows interesting wavelength-dependent photochromism. The structure of the same single crystal was characterized before (1, yellow) and after visible irradiation (l = 550 nm; 2, olive green), as well as after further UV irradiation (l = 300 nm, 3, dark green).In traditional organic syntheses, N-alkylated products are obtained from the reaction of organic amines and alkyl iodides under alkaline conditions, whereas alkyl iodides are obtained from alcohols activated by HI under acidic conditions. We demonstrate herein a new one-step approach to form N-alkylated products (i.e. the alkylated DAMP compound in 1) through in situ N-alkylation of organic amines and alcohols under acidic conditions by using a solvothermal technique. The existence of alkylated DAMP compound in 1 has been proved by 1 H NMR and ESI-MS spectra (see the Supporting Information). This synchronous process can be expanded and a series of metal iodide hybrid frameworks can be realized by control of the alcohols (C1-C4), amines (aliphatic and aromatic), and metal salts (Pb, Bi, Sn). As for the...

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“…Overall, it is a stepwise reaction. After irradiation by UV light with a wavelength of more than 300 nm, [21] R is promoted to the first singlet excited state 1 (np*). Subsequently, the excited-state conversions take place on the surface crossings (pp*) state decays nonradiatively through ISC to the ground state, the reaction preferentially yields A-P-II through A-TS-II, both favored thermodynamically and dynamically.…”

Section: The Proposed Favorable Photoinduced Rearrangement Reaction Pmentioning

confidence: 99%

“…In 1968, Matsuura and co-worker assumed that during the reaction an unstable intermediate is formed which subsequently yields a product through Diels-Alder and [2+2] cycloaddition reactions. [20] The critical intermediate, cyclopentadienone, involved in the subsequent reactions in the crystal, was recently characterized by Garcia-Garibay et al [21] It has been reported that under ultra-violet light irradiation, a-santonin, designated by R, undergoes a ring-closure reaction leading to a vital intermediate characterized by a three-membered carbon ring, denoted as INT. A subsequent carbon-bond cleavage takes place on the newly formed ring.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Studies on the Photoinduced Rearrangement Mechanism of α‐Santonin

et al. 2011

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α-Santonin is the first organic compound observed to feature a photoinduced rearrangement and is now known to undergo a series of photochemical processes under UV irradiation. On the basis of the considerable interest of this system as a prototype, and of the yet limited insights reached for the basic photo mechanisms, we calculate the high-level electronic structures and explore the potential energy surfaces (PES) of α-santonin in the ground and lowest-lying excited states, their couplings, and the possible photoinduced isomerization pathways. The calculations identify the low-lying singlet excited state (1)(nπ*) accessible under light irradiation, which decays to the low-energy (3)(ππ*) state through an intersystem crossing in the Franck-Condon region to initiate the photoinduced rearrangement. The initial reaction from the C3-C5 bond coupling, which takes place on the (3)(ππ*) state potential energy surface, leads to a three-membered alkyl-ring compound intermediate state INT. The following photochemical reactions have the possibility to arise from two distinct C-C bond cleavages, C4-C5 and C3-C4, denoted as path A and path B. Path A is favored both dynamically on the excited-state PES and thermodynamically on the ground-state PES in vacuo. Experiments show that it also becomes the dominant photoinduced rearrangement process in the crystal, which can be explained by considering the requirement for less space and the stacking effect under the confined environment. Path B is dynamical advantaged both on the ground- and excited-state PESs in a weak polar solvent, such as dioxane. Once the biradical intermediate B-INT is accessible on the ground-state PES, the formation of the product B-P is almost barrier free.

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The Photoarrangement of α-Santonin is a Single-Crystal-to-Single-Crystal Reaction: A Long Kept Secret in Solid-State Organic Chemistry Revealed

Cited by 103 publications

References 11 publications

Colossal positive and negative thermal expansion and thermosalient effect in a pentamorphic organometallic martensite

Colossal positive and negative thermal expansion and thermosalient effect in a pentamorphic organometallic martensite

Wavelength‐Dependent Photochromic Inorganic–Organic Hybrid Based on a 3D Iodoplumbate Open‐Framework Material

Theoretical Studies on the Photoinduced Rearrangement Mechanism of α‐Santonin

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