4-(2-Carboxyvinyl)-α-cyanocinnamic acid dimethyl ester, a photooligomerizable crystal

Nakanishi, Hachiro; Sasada, Yoshio

doi:10.1107/s0567740878003003

Cited by 10 publications

(5 citation statements)

References 6 publications

(6 reference statements)

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“…For detailed analysis only structures which contained Cl-Cl distances <4.2 A were considered. Out of a total of 132 structures, only 22 did not contain any Cl-Cl interaction within the above limit. In the 110 structures, there were 341 interactions.…”

Section: Resultsmentioning

confidence: 96%

A study on the photochemical dimerization of coumarins in the solid state

Gnanaguru¹,

Ramasubbu²,

Venkatesan³

et al. 1985

J. Org. Chem.

237

191

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Solid-state photochemical behavior of 28 substituted coumarins has been investigated. Of these twelve underwent photodimerization and this is remarkable in light of the inertness of coumarin itself in the solid state. X-ray crystallographic investigation of eight coumarins was undertaken with the view of understanding the role of packing in the crystal on their solid-state reactivity. Important findings include the identification of acetoxy and chloro substituents as useful "crystal engineering" groups and the results pertaining to subtler aspects of topochemical postulates. X-ray crystal structure analyses of 7-chlorocoumarin and 7-methoxycoumarin reveal packing modes which are not commonly met. The former is arranged in a 0-type packing, the center-center distance between the reactive double bonds being 4.454 A, which lies beyond the so far accepted limit of 3.5-4.2 A. The reactive double bonds of 7-methoxycoumarin, on the other hand, are rotated by 656 with respect to each other with the center-center distance between the double bonds being 3.83 A. Inspite of these unfavorable arrangements photodimerization of the above two coumarins in the solid state occurs through a topochemical process with large dimer yields. A careful analysis of the X-ray crystallographic results obtained from our investigations reveals that the two double bonds in the reactive crystals may be displaced with respect to each other both along the molecular plane as well as along the double bond axis. Thus the normally accepted dictums that in the photoreactive crystals the doube bonds should be within a distance of 4.2 A and that they be parallel are no longer operational.

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Section: Resultsmentioning

confidence: 96%

A study on the photochemical dimerization of coumarins in the solid state

Gnanaguru¹,

Ramasubbu²,

Venkatesan³

et al. 1985

J. Org. Chem.

237

191

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“…One of the major reasons for investigations of these compounds is to analyse their intermolecular hydrogenbonding interactions from the point of view of crystal engineering, i.e. the design of new materials with particular chemical and physical properties (Nakanishi & Sasada, 1978;Bryan & White, 1982;Desiraju & Sarma, 1983;Desiraju et al, 1984;Desiraju & Sharma, 1991). It was found that intermolecular interactions, even weak hydrogen bonds, may play a major role in the self-assembly of molecules in crystals, in their speci®c molecular architecture and in their properties.…”

Section: Commentmentioning

confidence: 99%

Methyl 3-(4-methoxyphenyl)prop-2-enoate

et al. 2002

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The title molecule, C(11)H(12)O(3), is almost planar, with an average deviation of the C and O atoms from the least-squares plane of 0.146(4)A. The geometry about the C=C bond is trans. The phenyl ring and -COOCH(3) group are twisted with respect to the double bond by 9.3(3) and 5.6(5) degree, respectively. The endocyclic angle at the junction of the propenoate group and the phenyl ring is decreased from 120 degree by 2.6(2) degree, whereas two neighbouring angles around the ring are increased by 2.3(2) and 0.9(2) degree. This is probably associated with the charge-transfer interaction of the phenyl ring and -COOCH(3) group through the C=C double bond. The molecules are joined together through C-H...O hydrogen bonds between the methoxy and ester groups to form characteristic zigzag chains extended along the c axis.

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“…The photoreaction was carried out for lb in the same manner for 6 h. Monomer lb was quantitatively converted into dimer 2b. 2b: mp 191.5-193 °C dec; IR (KBr) 2250,1745,1600,1000, 990, 975, 850, 830 cm"1; NMR (CDC13) 0.96 (t, 6 H, J = 7 Hz), 4.04 (dq, 2 H, Ji = 11 Hz, J2 = 7 Hz), 4.09 (dq, 2 H, J\ = 11 Hz, J2 = 7 Hz), 5.17 (s, 2 ), 7.07 (d, 2 H, J = 16 Hz), 7.29 (d, 2 H, J = 16 Hz), 7.39 (m, 4 H), 7.52 (d, 4 H, J = 8 Hz), 7.61 (d, 4 H, J = 8 Hz), 8.56 (m, 4 H); UV (e in CH2C12) 315 nm (66 500).…”

Section: Methodsmentioning

confidence: 99%

“…H, J = 4 Hz), 7.16 (d, 2 H, J = 16 Hz), 7.32 (d, 2 H, J = 16 Hz),7.40 (m, 2 H),7.66 (d, 2 H, J = 9 Hz),8.03 (d, 2 H, J = 9 Hz),8.24 (s, 1 H),8.62 (m, 2 H); UV («in CH2C12) 360 nm (43 900).…”

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confidence: 99%