Nickel organometallic compounds containing optically active Schiff bases. A chiral carbon atom as a sensor of structural features †

1998 ◽  
pp. 1047-1052 ◽  
Author(s):  
Rosa M. Ceder ◽  
Jaume Granell ◽  
Guillermo Muller
Keyword(s):  
Carbon Atom ◽  
Schiff Bases ◽  
Organometallic Compounds ◽  
Structural Features ◽  
Optically Active ◽  
Chiral Carbon

Sm based initiators for the ring-opening polymerization of L-lactide

e-Polymers ◽  
2001 ◽  
Vol 1 (1) ◽  
Author(s):  
Seema Agarwal ◽  
Marc Karl ◽  
Kurt Dehnicke ◽  
Andreas Greiner
Keyword(s):  
Carbon Atom ◽  
Optical Activity ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Optically Active ◽  
Polymerization Catalysts ◽  
Time Intervals ◽  
Chiral Carbon

AbstractRing-opening polymerizations of L-lactide were carried out in the presence of Sm(II) (SmI2/Sm) and the Sm(III) complex [Sm(m-Cl){N(SiMe3)2}2(THF)]2 (Me: CH3, THF: tetrahydrofuran). The polymerizations were performed using different mole ratios of monomer to initiator and for different time intervals. The complexes were found to be active polymerization catalysts and led to the synthesis of semicrystalline, optically active poly(L-lactide) retaining about 95.5% of the optical activity. This shows that - with the initiator systems used - polymerization proceeds with the retention of configuration at the chiral carbon atom.

Thermotropic Chiral Nematic Polymers as Optical Materials

1989 ◽  
Vol 175 ◽  
Author(s):  
S.H. Chen ◽  
M.L. Tsai ◽  
S.D. Jacobs
Keyword(s):  
Optical Materials ◽  
Helical Structure ◽  
Structural Features ◽  
Optically Active ◽  
Structure Property ◽  
Chiral Compound ◽  
Structure Property Relationships ◽  
Chiral Nematic ◽  
Chiral Structures ◽  
Nematic Polymers

AbstractChiral nematic copolymers based on optically active cholesterol, dihydrocholesterol, (R)-(+)- and (S)-(−)-1-phenylethylamine, and (+)- and (−)- isopinocampheol were synthesized and characterized for the investigations of thermotropic and optical properties. Although helical sense does not appear to correlate with the sign of [α]D of the precursor chiral compound as suggested by the observations of cholesteryl and dihydrocholesteryl copolymers, the inversion of chirality in the pendant group, (R)-(+)- vs (S)-(−)-1-phenylethylamine, does lead to the opposite handedness in the resultant helical structure. To better understand the structure-property relationships involving helical sense and twisting power, systematic studies of the roles played by both nematogenic and chiral structures as well as other structural features of the comonomers should be conducted.

Ferroelectric Liquid Crystals: Synthesis and Thermal Behavior of Optically Active, Three-Ring Schiff Bases and Salicylaldimines

2018 ◽  
Vol 13 (8) ◽  
pp. 1012-1023 ◽  
Author(s):  
Bhyranalyar N. Veerabhadraswamy ◽  
Doddamane S. Shankar Rao ◽  
Channabasaveshwar V. Yelamaggad
Keyword(s):  
Liquid Crystals ◽  
Thermal Behavior ◽  
Schiff Bases ◽  
Optically Active ◽  
Ferroelectric Liquid Crystals
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