Skip to content

Perhydrohelicenes and other diamond-lattice based hydrocarbons: The choreography of inversion

Research output: Contribution to journalArticle

Standard

Perhydrohelicenes and other diamond-lattice based hydrocarbons : The choreography of inversion. / Alder, Roger W.; Butts, Craig P.; Sessions, Richard B.

In: Chemical Science, Vol. 8, No. 9, 2017, p. 6389-6399.

Research output: Contribution to journalArticle

Harvard

APA

Vancouver

Author

Bibtex

@article{7142f5b52647428180cdd47c0e61c1e7,
title = "Perhydrohelicenes and other diamond-lattice based hydrocarbons: The choreography of inversion",
abstract = "Overall inversion in fused cyclohexane oligomers 2, 3, and 4 (all based on cis-decalin 1) occurs by a rolling process involving no more than two adjacent rings in twist-boat conformations at any time. These inverting rings move along the oligomer in processes that are precisely choreographed by the adjacent chairs. Actual inversion mechanisms can be stepwise [CC → TC → TT → C′T → C′C′], as for cis-decalin, but it is shown that a concerted alternative [CC → TC → C′T → C′C′] is enforced in 2. The all-cis,anti,cis-isomers of perhydrohelicenes 4 are based on the diamond lattice and have remarkably low strain energies. Helix inversion in 4 is compared with that in helicenes 5. For both, the intermediates and transition states have shapes broadly like kinked old-style telephone cables. In both cases barriers increase with the length of the system to eventually reach a plateau value of ca. 120 kJ mol-1 for 4, much lower than that for 5 (320-350 kJ mol-1). While rolling inversion only requires two adjacent rings in twist-boat conformations at any instant, inversion in propellane 6 requires all three rings be converted to twist-boats, and the S4 symmetric hydrocarbon 7 requires all four rings to be converted to twist-boats. As a consequence, 7 probably has the highest barrier of any non-oligomeric cis-decalin derived structure (87.3 kJ mol-1 at B3LYP/6-31G∗).",
author = "Alder, {Roger W.} and Butts, {Craig P.} and Sessions, {Richard B.}",
year = "2017",
doi = "10.1039/c7sc01759f",
language = "English",
volume = "8",
pages = "6389--6399",
journal = "Chemical Science",
issn = "2041-6520",
publisher = "Royal Society of Chemistry",
number = "9",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Perhydrohelicenes and other diamond-lattice based hydrocarbons

T2 - The choreography of inversion

AU - Alder, Roger W.

AU - Butts, Craig P.

AU - Sessions, Richard B.

PY - 2017

Y1 - 2017

N2 - Overall inversion in fused cyclohexane oligomers 2, 3, and 4 (all based on cis-decalin 1) occurs by a rolling process involving no more than two adjacent rings in twist-boat conformations at any time. These inverting rings move along the oligomer in processes that are precisely choreographed by the adjacent chairs. Actual inversion mechanisms can be stepwise [CC → TC → TT → C′T → C′C′], as for cis-decalin, but it is shown that a concerted alternative [CC → TC → C′T → C′C′] is enforced in 2. The all-cis,anti,cis-isomers of perhydrohelicenes 4 are based on the diamond lattice and have remarkably low strain energies. Helix inversion in 4 is compared with that in helicenes 5. For both, the intermediates and transition states have shapes broadly like kinked old-style telephone cables. In both cases barriers increase with the length of the system to eventually reach a plateau value of ca. 120 kJ mol-1 for 4, much lower than that for 5 (320-350 kJ mol-1). While rolling inversion only requires two adjacent rings in twist-boat conformations at any instant, inversion in propellane 6 requires all three rings be converted to twist-boats, and the S4 symmetric hydrocarbon 7 requires all four rings to be converted to twist-boats. As a consequence, 7 probably has the highest barrier of any non-oligomeric cis-decalin derived structure (87.3 kJ mol-1 at B3LYP/6-31G∗).

AB - Overall inversion in fused cyclohexane oligomers 2, 3, and 4 (all based on cis-decalin 1) occurs by a rolling process involving no more than two adjacent rings in twist-boat conformations at any time. These inverting rings move along the oligomer in processes that are precisely choreographed by the adjacent chairs. Actual inversion mechanisms can be stepwise [CC → TC → TT → C′T → C′C′], as for cis-decalin, but it is shown that a concerted alternative [CC → TC → C′T → C′C′] is enforced in 2. The all-cis,anti,cis-isomers of perhydrohelicenes 4 are based on the diamond lattice and have remarkably low strain energies. Helix inversion in 4 is compared with that in helicenes 5. For both, the intermediates and transition states have shapes broadly like kinked old-style telephone cables. In both cases barriers increase with the length of the system to eventually reach a plateau value of ca. 120 kJ mol-1 for 4, much lower than that for 5 (320-350 kJ mol-1). While rolling inversion only requires two adjacent rings in twist-boat conformations at any instant, inversion in propellane 6 requires all three rings be converted to twist-boats, and the S4 symmetric hydrocarbon 7 requires all four rings to be converted to twist-boats. As a consequence, 7 probably has the highest barrier of any non-oligomeric cis-decalin derived structure (87.3 kJ mol-1 at B3LYP/6-31G∗).

UR - http://www.scopus.com/inward/record.url?scp=85027869262&partnerID=8YFLogxK

U2 - 10.1039/c7sc01759f

DO - 10.1039/c7sc01759f

M3 - Article

VL - 8

SP - 6389

EP - 6399

JO - Chemical Science

JF - Chemical Science

SN - 2041-6520

IS - 9

ER -