geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

DFT prediction of multitopic N-heterocyclic carbenes using Clar's aromatic sextet theory


, : DFT prediction of multitopic N-heterocyclic carbenes using Clar's aromatic sextet theory. Journal of Organic Chemistry 78(8): 3918-3924

Existence of several multitopic N-heterocyclic carbene (NHC) ligands with up to four carbene centers have been predicted on the basis of Clar's aromatic sextet theory. Assessment on stability and reactivity of NHCs was made by quantifying aromaticity, aromatic stabilization energy (E(aroma)), strength of carbene lone pair, proton affinity, and CuCl binding energy. On NICS(0) and HOMA scales of aromaticity, several NHCs showed high aromaticity, while E(aroma) (17.2-19.4 kcal/mol) indicated substantial stability for the N-heterocycle. Homodesmotic reactions suggested that heat of formation of most of the newly designed carbenes is very close to that of the existing bis-NHCs. Designing a multitopic ligand through branching via C(sp3) linkage was very effective as it improved the stability of the carbene. Electrostatic potential minimum (V(min)) at the carbene lone pair suggested that annelation of heterocycle to a benzenoid ring or branching through C(sp3) linkage can only marginally influence the electron donating power of the ligand. Hence, all multitopic NHCs showed proton affinity (252.3-267.4 kcal/mol) and CuCl binding energy (62.9-66.6 kcal/mol) very close to those of 1,3-dimethylimidazolidine-2-ylidene (1). It has also been demonstrated that branched multitopic 3-dimensional NHCs are attractive for designing metal-organic framework with narrow (1-1.5 nm) cage/pore size.

US$19.90

PMID: 23461408

DOI: 10.1021/jo400305x


Other references

Nishio, J.; Fukuda, M., 1998: Influence of temperature and rooting-promoter on the formation of root-primodia and on the rooting of chrysanthemum cuttings under storage. In order to promote rooting for direct planting cuttings in a lighting cultivation of chrysanthemum, we clarified the effects of light, temperature and term of storage of the cuttings, and analyzed ways of using rooting promoters as a pre-treatmen...

Adachi, T.; Kobayashi, S.; Yamashita, K.; Shimote, K.; Tsunematsu, T., 1992: A case of recurrent cerebral hemorrhage considered to be cerebral amyloid angiopathy by cerebrospinal fluid examination. A 73-year-old man was admitted with gait disturbance and dysarthria. He showed right-side cerebellar ataxia. Computed tomography of brain showed left thalamic bleeding. Nine months later, he was admitted again because of seizure and consciousness...

Trzebski Robert; Evancara Jan, 1996: Gravity investigation of deep crustal structures by Linsser-filtering. Investigation of tectonic structures is an essential part of geophysical exploration. Seismic surveys are usually performed along predetermined profile lines, so that an adequate areal mapping of faults can be obtained only by costly 3D-seismics a...

Stern, M.P., 2002: The search for type 2 diabetes susceptibility genes using whole-genome scans: an epidemiologist's perspective. Most whole-genome scan studies of type 2 diabetes have ascertained families on affected sibpairs. Although assuring enrollment of multiplex families, this strategy may lead to the enrollment of unrepresentative families, particularly in low-risk p...

Oziminski, W.P.; Krygowski, T.M., 2011: Natural bond orbital approach to the transmission of substituent effect through the fulvene and benzene ring systems. Electronic structure of 22 monosubstituted derivatives of benzene and exocyclically substituted fulvene with substituents: B(OH)(2), BH(2), CCH, CF(3), CH(3), CHCH(2), CHO, Cl, CMe(3), CN, COCH(3), CONH(2), COOH, F, NH(2), NMe(2), NO, NO(2), OCH(3...

Karaev A.L.; Kovler M.A.; Avakumov V.M., 1991: Antihypoxic action of carnitine chloride. D, L-carnitine chloride antihypoxic action was studied. Carnitine chloride (100-200 mg/kg) was found to increase mouse life expectancy under different experimental models of hypoxia both at acute and chronic administration.

Flo, C.; Lopes, F., D.T.Q.S.; Kasahara, D., I.; Silva, A.-Cecilia, D.; Jesus, R., C.C.; Rivero, D., H.R.F.; Saldiva, P., H.N.; Martins, M., A.; Jacob-Filho, W., 2006: Effects of exercise training on papain-induced pulmonary emphysema in Wistar rats. The purpose of the present study was to evaluate the role of exercise training on the development of papain-induced emphysema in rats. Our hypothesis was that the increase in pulmonary tissue stretching associated with exercise could increase the...

Gilling, C.E.; Carlson, K.A., 2009: The effect of OTK18 upregulation in U937 cells on neuronal survival. The intent of this study was to characterize the effect OTK18 upregulation in monocytic cells had on neuronal survival. The human monocytic cell line, U937, was differentiated into macrophages or left as an undifferentiated monocyte. These cells w...

Kabakova, R.I., 1967: The new genus Azeria from the Akchagylian deposits of Azerbaidjan. Izv Akad Nauk azerb SSR Ser geol -geogr (a'nefti): 2: 15-19

McBurney, M.I., 1991: Starch malabsorption and stool excretion are influenced by the menstrual cycle in women consuming low-fibre Western diets. The objectives of the study were to determine whether the follicular (F; days 6-11)and luteal(L; days 16-21)phases of the menstrual cycle were associated with changes in starch malabsorption, stool bulking, stool mucinase, and .beta.-glucuronidase...