Calix[4]phyrins. Effect of peripheral substituents on conformational mobility and structure within a series of related systems.
A new, stepwise synthesis of calix[4]phyrins is described. It relies on the condensation of a ketone with pyrrole to form a dipyrromethane containing a quaternary carbon center that is subsequently condensed with an aromatic aldehyde. This methodology, in contrast to the previous rational approach described by this group (involving formation of a trisubstituted dipyrromethane via the condensation of an aldehyde with pyrrole, followed by condensation of this dipyrromethane with acetone), allows for a variety of bulky, ketone-derived substituents to be incorporated into the meso-like positions. The resulting systems, while all containing the same central macrocyclic core, display conformational properties that reflect the nature of these meso-like substituents; these conformational features were independently assessed by X-ray diffraction analysis, NMR spectroscopy, and quantum chemical calculations.
Dolenský
Bohumil
B
Department of Analytical Chemistry and Laboratory of NMR Spectroscopy, Institute of Chemical Technology, Technická 5, 16628 Praha 6, Czech Republic.
Kroulík
Jirí
J
Král
Vladimír
V
Sessler
Jonathan L
JL
Dvoráková
Hana
H
Bour
Petr
P
Bernátková
Markéta
M
Bucher
Christophe
C
Lynch
Vincent
V
D047250:Calixarenes / Q000138:chemical synthesis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D014961:X-Ray Diffraction
D011166:Porphyrins; D047250:Calixarenes