Title

Structural Identification of a Novel Axially Chiral Binaphthyl Fluorene Based Salen Ligand in Solution Using Electronic Circular Dichroism: A Theoretical Experimental Analysis

Authors

Authors

C. Diaz; A. Frazer; A. Morales; K. D. Belfield; S. Ray;F. E. Hernandez

Comments

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Abbreviated Journal Title

J. Phys. Chem. A

Keywords

3-PHOTON ABSORPTION ENHANCEMENT; ONE-PHOTON; COMPLEXES; DERIVATIVES; DENSITY; MOLECULES; PHOTOSTABILITY; DIETHYLZINC; ALDEHYDES; CATALYSTS; Chemistry, Physical; Physics, Atomic, Molecular & Chemical

Abstract

A novel axially chiral binaphthyl fluorene based salen ligand, AFX-155 [2,2'-(1E,1'E)-(R)-1,1'-binaphthyl-2,2'diylbis(azan-1-yl-1-ylidene)bis(methan-1-yl-1-ylidene)bis(4-((7-(diphenylamino)-9,9-dihexyl-9H-fluoren-2-1)ethynyl)phenol)], with potential applications in homogeneous catalysis, biophotonics, and sensing was synthesized. A full comparative theoretical experimental analysis of the UV-vis and electronic circular dichroism (ECD) spectra of the 10 primary isomers, comprising stereoisomers and optical isomers, revealed the presence of the unique structure in tetrahydrofuran (THF) solution, the trans-R-intra//trans-R-extra. A proposed route of attack of the (R)-(+)-2,2'-diamino-1,1'-binapthalene onto a salicaldehyde 5-(2-(2-(diphenylamino)-9,9-dihexyl-9H-fluoren-7-yl)ethynyl)-2-hydroxybenzaldehyde followed by a consecutive attack of the resulting species onto another salicaldehyde, both via Burgi:Dunitz trajectory, validates the unambiguous formation of the established isomer. Steric hindrances seem to be the determinant factor that defines the 3D structural conformation of this particular stereoisomer of AFX-155 with triple axial chirality. The determination of every optimal structure and the dominant conformers of AFX-155 were calculated evaluating, in CONFLEX, their steric energies using force fields at MMFF94S (2006-11-24HGTEMP) level in gas phase. The geometry of the conformers was optimized in THF (using PCM) using Gaussian 09 at the DFT/B3LYP level of theory and 6-31G* basis set. The first 100 electronic excited states were calculated using the same level of theory and basis set.

Journal Title

Journal of Physical Chemistry A

Volume

116

Issue/Number

10

Publication Date

1-1-2012

Document Type

Article

Language

English

First Page

2453

Last Page

2465

WOS Identifier

WOS:000301509400008

ISSN

1089-5639

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