Long-Range σ−π Interactions in Tetrahydro-<i>4H</i>-thiopyran End-Capped Oligo(cyclohexylidenes). Photo-Electron Spectroscopy, ab Initio SCF MO Calculations, and Natural Bond Orbital Analyses
作者:Albert W. Marsman、Remco W. A. Havenith、Sabine Bethke、Leonardus W. Jenneskens、Rolf Gleiter、Joop H. van Lenthe、Martin Lutz、Anthony L. Spek
DOI:10.1021/jo000199y
日期:2000.7.1
alpha- and omega-end positions the pi-type sulfur lonepair bands [Lppi(S)] split significantly by deltaIvj approximately 0.3 to 0.4 eV (delta-epsilonj approximately 0.3 to 0.4 eV), i.e. sigma-pi interactions over distances of ca. 8 and 12 A, respectively, occur. The magnitude of the interactions and the observed splittings are independent of the anti and syn conformations of the oligo(cyclohexylidene) hydrocarbon