synthesis and conformational study of a novel macrocyclic chiral(salen) ligand and its uranyl and mn complexes合成和构象研究的一种新型大环的手性(伦)配体和其铀酰和锰配合物.pdfVIP

Molecules 2010, 15, 1442-1452; doi:10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Article Synthesis and Conformational Study of a Novel Macrocyclic Chiral(Salen) ligand and its Uranyl and Mn Complexes Maria E. Amato, Francesco P. Ballistreri, Andrea Pappalardo, Gaetano A. Tomaselli * and Rosa M. Toscano Dipartimento di Scienze Chimiche, Università di Catania, Viale Andrea Doria 6, Catania 95125, Italy; E-Mails: eamato@unict.it (M.E.A.); fballistreri@unict.it (F.P.B.); andrea.pappalardo@unict.it (A.P.); rmtoscano@unict.it (R.M.T.) * Author to whom correspondence should be addresses; E-Mail: gtomaselli@unict.it. Received: 21 December 2009; in revised form: 20 January 2010 / Accepted: 2 March 2010 / Published: 9 March 2010 Abstract: A novel chiral macrocyclic ligand incorporating a chiral salen moiety into a framework containing two biphenyl units was synthesized. Structural properties and conformational aspects of the free ligand and an UO complex were studied by using NMR 2 spectroscopy in solution and MM calculations. The Mn(III) complex was tested as catalyst in enantioselective oxidation of prochiral unfunctionalized olefins to the corresponding optically active epoxides under very mild conditions. Keywords: macrocyclic chiral ligand; salen; enantioselectivity; epoxidation 1. Introduction The successful design, synthesis and use of molecules capable of the selective recogni