Premium
Chiral M 3 L 2 Self‐Assembled Capsules through Metal Coordination of Enantiopure Ligating Benzocyclotrimers: NMR Spectroscopic and ESI Mass Spectrometric Investigation
Author(s) -
Tartaggia Stefano,
De Lucchi Ottorino,
Gambaro Andrea,
Zangrando Roberta,
Fabris Fabrizio,
Scarso Alessandro
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201203598
Subject(s) - enantiopure drug , chemistry , denticity , trifluoromethanesulfonate , supramolecular chemistry , metal , nitrile , two dimensional nuclear magnetic resonance spectroscopy , pyridine , yield (engineering) , stereochemistry , crystallography , enantioselective synthesis , medicinal chemistry , organic chemistry , materials science , crystal structure , catalysis , metallurgy
The synthesis of enantiopure (+)‐benzotricamphor syn ‐ 5 , an important chiral C 3 ‐symmetric rigid building block for supramolecular applications, was studied in detail to reduce the number of steps and to increase the diastereoselectivity and overall yield. The new synthetic procedure allowed larger amounts of syn ‐ 5 to be obtained and used for the preparation of new derivatives, such as the corresponding tris ‐trifluoromethanesulfonate syn ‐ 12 , which was efficiently transformed into (+)‐benzotribornenetrinitrile syn ‐ 1 and (+)‐benzotribornenetris(ethynyl‐4‐pyridine) syn ‐ 2 . The previously reported (+)‐benzotricamphortrioxime syn ‐ 6 was transformed into tris‐nitrile syn ‐ 3 by Beckman reaction. Compounds syn ‐ 1 – 3 were employed as multidentate ligands for silver(I) and platinum(II) centres in apolar solvents. The linear coordination geometry of Ag I and square‐planar geometry of cis ‐chelated Pt II in combination with the chiral tripodal ligands syn ‐ 1 – 3 led to the formation of chiral enantiopure capsules with M 3 L 2 stoichiometry, as confirmed by 2D NMR NOESY and DOSY experiments as well as ESI mass spectrometry.