Fluorinated cyclacenes - AM1 treatment

Türker, Burhan Lemi
The peripherally fluorinated Huckel type cyclacenes having 3-7 benzenoid rings (R) were considered for AM1 (restricted Hartree-Fock) type semiempirical quantum chemical treatment. The cyclacenes having one or two of the peripheries completely fluorinated constitute type-I and type-H structures, respectively. All of them were found to be stable. Type-I systems are endogenic but type-II structures, R:5 onwards are exogenic. The cryptoannulenic effect was found to be operative partly on the heats of formations of type-I systems. Whereas in both systems, the HOMO, LUMO and the frontier molecular orbital energy gaps are strongly influenced by the cryptoannulenic effect.


Cyclacene tubes having silaannulenic peripheries - AM1 treatment
Türker, Burhan Lemi; Bayer, I (2000-07-01)
The cyclacene tubes T(R, r) consisting of the Huckel type intermolecularly unioned (r = 6) cyclacenes having R arenoid rings (R = 3 - 6) and a single silaannulenic periphery are considered for AM1 type semiempirical molecular orbital calculations. The cases in which the silaannulenic periphery occupies different locations (layers A-D from top to middle) along the tube axis are investigated. It has been found that doping of silicon atoms in the top (or bottom) periphery of the cyclacene tubes has a stabilizi...
Borazine embedded cyclacenes - a theoretical study
Turker, L; Erkoç, Şakir (2000-10-23)
Semiempirical molecular orbital treatment at the level of an AM1 type has been performed on the Huckel type borazine embedded cyclacenes having 3-10 arenoid rings. Although, the thermodynamic energies exhibit no cryptoannulenic effect depending on the 4m or 4m + 2 nature of the peripheral circuits, the HOMO and LUMO energies, as well as the interfrontier molecular orbital gaps are affected by the cryptoannulenic effect. In general, the peripheries have opposite charge accumulation leading to the arousal of ...
Boron trifluoride mediated addition of nucleophiles to endo- and exo-substituted norbornene derivatives
İŞLEYEN, Alper; SAYRAÇ, Tuğmaç; Doğan, Özdemir (2004-01-01)
Remote substituent effects on the regioselectivity and stereoselectivity in the boron trifluoride mediated addition of nucleophiles (iodide and bromide) to endo- and exo-2-substituted norbornene derivatives have been investigated. The main products of the reactions resulted from the regioselective addition of nucleophiles to the double bond of norbornene derivatives. Products resulting from the Wagner-Meerwein type rearrangement were also isolated in considerable amounts. All of the reactions gave the addit...
Homoconjugated and Spiro Push-Pull Systems: Cycloadditions of Naphtho- and Anthradiquinones with Electron-Rich Alkynes
Dengiz, Çağatay (2017-07-01)
We report the synthesis and characterization of three new classes of push-pull chromophores using [2+2]-cycloaddition reactions of electron-rich alkynes and electron-poor alkenes. Previous investigations have focused on the reactions of cyano-substituted electron acceptors. This study demonstrates that cyano-free electron acceptors, naphtho- and anthradiquinones, can also be used to access extended push-pull systems. The effects of the structural changes on the spectroscopic and electronic properties were i...
The effect of para-cyclophane structure on cyclacenes
Türker, Burhan Lemi (2000-02-01)
Semiempirical molecular orbital treatment at the level of AMI type has been performed on the Huckel type cyclacenes having the normal and the skew type para-cyclophane moiety embedded into their structures. The cyclophane effect is found to be operative on the lower members by veiling the cryptoannulenic effect which is influential on the heats of formation values and the frontier molecular orbital energies of the higher members as well as the parent cyclacenes.
Citation Formats
B. L. Türker, “Fluorinated cyclacenes - AM1 treatment,” JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, pp. 57–61, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/62269.