Computational (MM, MD and MDMM) study of bidentate complexes of ( R, R)- and meso-α,α′-bis(trifluoromethyl)-9,10-anthracenedimethanol with cis-1-amino-2-indanol

Abstract

Results are reported from molecular mechanics (MM), molecular dynamics (MD) and a combined mode – MD with a subsequent MM minimization, of the complexes of the chiral solvating agent (CSA) α,α′-bis(trifluoromethyl)-9,10-anthracenedimethanol ( 1) in two of its diastereoisomeric forms (( R, R)- and meso-) with the substrates (1 S,2 R)- and (1 R,2 S)- cis-1-amino-2-indanol ( 2). Our computational work was stimulated by preceding NMR study of the enantio differentiation capacity of the CSA manifested in the formation of bidentate complexes with the substrates. The molecular modeling and simulation studies gave possible structures and relative stabilities of the associated species. MM minimizations were sufficient in order to find the lowest energy minima of meso- 1/(1 S,2 R)- 2 and ( R, R)- 1/(1 S,2 R)- 2, while the lowest energy structure of ( R, R)- 1/(1 R,2 S)- 2 was detected after the MD and MDMM studies. The complexes with the ( R, R)- 1 isomer have higher total energies than those with meso- 1, in accord with an NMR estimate for longer lifetimes of the complexes with meso- 1.