Open-Cage Fullerene Derivatives with 15-Membered-Ring Orifices

2004 ◽  
Vol 69 (13) ◽  
pp. 4524-4526 ◽  
Author(s):  
Georgios C. Vougioukalakis ◽  
Kosmas Prassides ◽  
Josep M. Campanera ◽  
Malcolm I. Heggie ◽  
Michael Orfanopoulos
Keyword(s):  
Membered Ring ◽  
Fullerene Derivatives

Efficient Synthesis of Open-Cage Fullerene Derivatives Having 16-Membered-Ring Orifices

2007 ◽  
Vol 72 (18) ◽  
pp. 7042-7045 ◽  
Author(s):  
Manolis M. Roubelakis ◽  
Yasujiro Murata ◽  
Koichi Komatsu ◽  
Michael Orfanopoulos
Keyword(s):  
Membered Ring ◽  
Efficient Synthesis ◽  
Fullerene Derivatives

FULLERENE DERIVATIVES: STRUCTURES AND STABILITIES OF C60O AND C70O

1992 ◽  
Vol 06 (23n24) ◽  
pp. 3821-3831 ◽  
Author(s):  
KRISHNAN RAGHAVACHARI
Keyword(s):  
Oxygen Atom ◽  
Infrared Spectra ◽  
Ground State ◽  
Membered Ring ◽  
Low Energy ◽  
Fullerene Derivatives ◽  
Hartree Fock ◽  
Semi Empirical ◽  
Very High ◽  
C Nmr

Semi-empirical (MNDO) and ab-initio Hartree-Fock (3–21G) calculations on the structures and stabilities of C 60 O and C 70 O are reported. Two low energy isomers of C 60 O , formed by an oxygen atom bridging the two different C–C bonds in C 60, have been found. The first isomer has an epoxide structure with a bridging oxygen across the bond between two fused six-membered rings in C 60 (bridging C–C≈1.6 Å). Its 13 C NMR and infrared spectra are consistent with those seen for the experimentally isolated form of C 60 O . However, the second isomer containing a bridging oxygen across the bond between a five- and a six-membered ring is slightly more stable and appears to be the ground state of C 60 O . The bridging C–C bond opens out to a distance of ≈2.1 Å in this isomer. Endohedral isomers of C 60 O are calculated to be very high in energy. For C 70 O , we have characterized eight isomers formed by an oxygen atom bridging each of the eight distinct C–C bonds in C 70. The ground state isomer corresponds to oxygen bridging across an equatorial C–C bond in C 70 which opens out to a distance of ≈2.2 Å. This structure is different from the bridged paracyclene-like isomer proposed previously for C 70 O . Comparison is made between C 60 O and C 70 O .

scholarly journals Efficient Synthesis of Open-Cage Fullerene Derivatives Having 16-Membered-Ring Orifices.

ChemInform ◽  
2007 ◽  
Vol 38 (49) ◽  
Author(s):  
Manolis M. Roubelakis ◽  
Yasujiro Murata ◽  
Koichi Komatsu ◽  
Michael Orfanopoulos
Keyword(s):  
Membered Ring ◽  
Efficient Synthesis ◽  
Fullerene Derivatives

An Alternate Energy-Conserved Pathway for the Morita-Baylis-Hillman (MBH) Reaction

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Lower Energy ◽  
Aldol Reaction ◽  
Membered Ring ◽  
Ammonium Ion ◽  
Alternate Energy ◽  
Ring Transition State ◽  
Mbh Reaction

An new overall lower energy pathway for the amine-catalysed Morita-Baylis-Hillman reaction is proposed from computations at the M06-2X/6-311++G(d,p) level. The pathway involves proton-transfer from the ammonium ion to the alkoxide formed from the aldol reaction through a seven-membered ring transition state (TS) structure followed by highly exothermic Hofmann<i> </i>elimination through a five-membered ring TS structure to form the product and also release the catalyst to carry on with the process all over again.

An Alternate Energy-Conserved Pathway for the Morita-Baylis-Hillman (MBH) Reaction

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Proton Transfer ◽  
Transition State ◽  
Lower Energy ◽  
Aldol Reaction ◽  
Membered Ring ◽  
Ammonium Ion ◽  
Alternate Energy ◽  
Ring Transition State ◽  
Mbh Reaction

An new overall lower energy pathway for the amine-catalysed Morita-Baylis-Hillman reaction is proposed from computations at the M06-2X/6-311++G(d,p) level. The pathway involves proton-transfer from the ammonium ion to the alkoxide formed from the aldol reaction through a seven-membered ring transition state (TS) structure followed by highly exothermic Hofmann<i> </i>elimination through a five-membered ring TS structure to form the product and also release the catalyst to carry on with the process all over again.

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