Phani Raj Pokkuluri

The novel solid state and solution phase photochemistry of dimethyl 9-chloromethyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate

Abstract Although the triplet excited state behavior of dimethyl 9-chloromethyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate ( 5 ) is normal, di-π-methane photorearrangement to a 4:1 mixture of regioisomers 6 and 7 , its singlet excited state reactivity is unusual and involves the formation of the novel photoproducts 8 and 9 . The mechanism by which these products are formed is thought to involve photorearrangement to the 1,4-biradical 10 followed by a non-concerted chlorine atom migration. Photoproducts 8 and 9 are more prevalent in solid state photolyses compared with those carried out in solution, a result that may be related to a favorable (4.28 A) intermolecular C · Cl contact in crystals of 5 .

Control of regioselectivity through relief of steric crowding in the di-π-methane photorearrangement of 9,10-ethenoanthracene derivatives

Abstract Product structures and quantum yields for the solution phase di-π-methane photorearrangement of the 9,10-ethenoanthracene derivatives 1–4 have been determined. The results are consistent with a model in which relief of steric crowding is the factor that governs regioselectivity.

An ethenonaphthalene and one of its photolysis products

Photolysis of methyl 2-benzoyl-1,4-dihydro-1,4-ethenonaphthalene-3-carboxylate (4) produces two di-π-methane photoproducts in solution, but three different products in the solid state. The structures of (4) and an unusual solid-state photoproduct methyl 6c-benzoyl-2a,2b,6b,6c-tetrahydrobenzo[a]cyclopropa[cd]pentalene-6b-carboxylate (13) have been determined by X-ray crystal analyses

Surface versus bulk reactivity in solid state organic chemistry

Abstract Dibenzobarrelene derivative 1 exhibits different reactivity when photolyzed in the form of large single crystals, as a polycrystalline powder and in solution.

12-Methyl-9-hydroxymethyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate lactone

The structure of an achiral ester-lactone, C 20 H 14 O 4 (1), which crystallizes spontaneously in space group P2 1 2 1 2 1 , has been determined. Solid-state photolysis gives two products, one of which is produced as a racemate, while the other is formed in near-quantitative enantiomeric excess; the optical activity of the latter product probably results from intermolecular steric effects

Dimethyl 9-phenyl-1,4-dihydro-1,4-ethenoanthracene-11,12-dicarboxylate

The molecule C 26 H 20 O 4 has normal geometry and dimensions. The methoxycarbonyl group that is remote from the phenyl substituent is conjugated with the C11=C12 double bond [C=C-C=O torsion angle=-163.2 (4) o , cos 2 (angle)=0.92], while the adjacent group is only very slightly conjugated [C=C-C=O torsion angle=68.1 (5) o , cos 2 (angle)=0.14]

Structure of dimethyl 9-formyl-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate

The structure of the title compound has been determined. The molecular structure and dimensions are normal, with the carboxyl group adjacent to the formyl substituent not conjugated with the C11=C12 double bond and the remote carboxyl group fully conjugated

Crystal structure and photochemistry of dimethyl 9,10-dichloro-9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate

Photolysis of the title 9,10-dichlorodibenzobarrelene-11,12-diester, (1), results in formation of a semibullvalene, dimethyl 4b,8b-dichloro-4b,8b,8c,8d-tetrahydrodibenzo[a,f]cyclopropa[cd]pentalene-8c,8d-dicarboxylate (2), and an additional photoproduct, dimethyl 4b,10-dichloro-4b,9,9a,10-tetrahydro-9,10-epidioxydibenzo[a,f]pentalene-9,9a-dicarboxylate (3), which contains an unusual peroxo-ring structure. The structures of (1), (2) and (3) have been determined by X-ray analysis

Cyclooctatetraene formation in the photolyses of dibenzobarrelene diesters

A study of cyclooctatetraenes (COTs) derived from the photolyses of dibenzobarrelene derivatives indicates the formation of two types of COT with different substitution patterns; the structures of one example of each type have been determined by X-ray crystal analyses. Crystal data: T=294 K, Cu Kα, λ=1.5418 A. (1), dimethyl 6-methyldibenzo[a,e]cyclooctatetraene-5,11-dicarboxylate, C 21 H 18 O 4 , M r =334.37, orthorhombic, Pna2 1 , a=18.364 (4), b= 10.485 (3), c=9.031 (4) A, V=1739 (2) A 3 , Z=4, D x =1.28 g cm -3 , F(000)=704, μ=6.8 cm -1 , R= 0.054 for 1303 reflexions. (2), 11-methyl-5-(2-propyl)dibenzo[a,e]cyclooctatetraene-5,11-dicarboxylate, C 22 H 20 O 4 , M r =348.40, monoclinic, P2 1 /n, a=9.121 (1), b= 20.486 (6), c=10.028 (1) A, β=100.91 (1)°, V=1839.9 (3) A 3 , Z=4, D x =1.26 g cm -3 , F(000)=736, μ=6.6 cm -1 , R= 0.043 for 2688 reflexions

Isopropyl hydrogen 9,10-dihydro-9,10-ethenoanthracene-11,12-dicarboxylate

The title compound, C 21 H 18 O 4 , exists in the crystal as hydrogen-bonded dimers, O-H...O=2.669 (3) A. The molecule has normal dimensions. The C=O bond of the CO 2 H group is conjugated with the C11=C12 double bond [C=C-C=O torsion angle -164.4 (3) o , cos 2 (angle) 0.93], but the C=O bond of the CO 2 C 3 H 7 group is not conjugated [C=C-C=O 65.6(3) o , cos 2 (angle) 0.17]