Straining strained molecules. III. The spectral and mutagenic properties and an alternate synthesis of diaceperylene and dicyclopenta[1,2,3-cd:1′,2′,3′-lm]perylene

Abstract

. Can. J. Chem. 70, 1015 (1992). The synthesis of diaceperylene (I) from 5,6-dilithioacenaphthene via nickel or cobalt catalysed couplings proceeded in better yield than a multistep synthesis involving formation of 5,5'-diacenaphthene first. Dehydrogenation of 1 to dicyclopenta[l,2,3-cd: 11,2',3'-lmlperylene (2) proved a better route than coupling of 5,6-disubstituted acenaphthylene derivatives. Ultraviolet, proton, and carbon nuclear magnetic resonance spectra and electrode reduction potential data of 1 and 2 are discussed with respect to molecular mechanics calculations of strain in these and related bridged naphthalenes. Both 1 and 2 were found to be weakly mutagenic in an Ames microsome test, in contrast to cyclopenta[cd]pyrene. [Traduit par la redaction]

Bridging the Gap: Attractive 3c–4e Interactions in peri‐Substituted Acenaphthylenes

“…[34] Crystal structures determined for 2, 3, 5, 6, 8-10 were analyzed and compared with previously reported analogous naphthalenes N1-N12 [18] and acenaphthenes A1-A12. [17] In addition, 1,2,5,6-tetrabromo-1,2-dihydroacenaphthylene A0 [28] was synthesized as an intermediate in the preparation of 13 and crystal structures determined for 13 and A0 were contrasted with the structure of 5,6-dibromoacenaphthene A13.…”

“…77 Se and 125 Te NMR spectra were recorded on a Jeol GSX 270 MHz spectrometer with δ(Se) and δ(Te) referenced to external Me 2 Se and Me 2 Te respectively, with a secondary reference for δ(Te) to diphenyl ditelluride (δ(Te) = 428 ppm). Assignments of 13 Alternative route to 13 following a modification of the procedure described by Mitchell and co-workers: [34] DDQ (10.9 g, 48.1 mmol) was added to a stirred solution of 5,6-dibromoacenaphthene A13 (10.0 g, 32.1 mmol) in benzene (250 mL) and the mixture was heated under reflux for 24 h. After cooling to room temperature, pentane (200 mL) was added and the mixture was filtered. The filtrate was passed through a short column of silica with a pentane eluent.…”

“…[2] The advancement of molecular orbital theory in the latter half of the last century led to a greater understanding of the bonding in hypervalent compounds, favoring the octet rule rather than conventional Lewis 2c-2e theory as a valid first approximation for the bonding in molecules of the main-block. [3] The concept of a three centre four-electron bond (3c-4e) subsequently introduced by Rundle [5] and Pimental [6] was able to explain the bonding without either violating the octet rule or invoking ionic bonding and later evolved to include four-and five-centre, six electron bonds (4c-6e, 5c-6e). [7] With the help of increasingly sophisticated calculations, novel bonding scenarios are continuing to be uncovered, [8] however identifying synthetic routes to these systems is essential for corroborating theoretical predictions, which are not always unambiguous.…”

“…Debromination to the target compound 13 was subsequently achieved by treating A0 with five equivalents of zinc and refluxing in glacial acetic acid for four hours (yield 86%, Scheme 1). [33] An alternative route to 13, reported by Mitchell and co-workers, [34] converts 5,6-dibromoacenaphthene A13 directly to the product in one step, using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in refluxing benzene (24 h) to dehydrogenate the ethane bridge (yield 25%, Scheme 1). Scheme 1.…”

Sterically Encumbered Tin and Phosphorus peri-Substituted Acenaphthenes

“…incorporating bulky tin-tin moieties in the proximal positions ([Acenap(SnR3)2] Acenap = acenaphthene-5,6-diyl; R3 = Ph3 (1), Me3 (2); [(Acenap)2(SnMe2)2] (3)) 27 and compare the degree of repulsion in these systems to heteroleptic bis(phosphines) 4 and 5 ([Acenap(PR2)(P i Pr2)] R2 = Ph2 (4), Ph( i Pr) (5) All spectra were run in CDCl3; δ (ppm), J (Hz). Splay angle [b] 26.8 24.6 13.8…”