Fig 1.
Aromatic biaryl systems distributed in three groups based on the major factor that leads to their corresponding CEP.
The dihedral angle being studied in each of the fragments is indicated with stars, with the orientation as drawn defining 0°. Table indicates the figure where each CEP is represented in the paper.
Fig 2.
a) Comparison of the CEP for biphenyl 1 in with that of the para substituted biphenyls (2–4), b) Representation of fragments 1, 2 and 3 plus the charge-separated resonance form of structure 4.
Fig 3.
a) Comparison between biphenyl 1 and phenylpyridines (5, 6, 7), b) Charge-separated resonance forms for 2- and 4-phenylpyridines, 5 and 7, c) Histogram extracted from ConQuest repository for single ligands that contain the corresponding fragment, d) Diagram shows a potential electronic repulsion at 90° between electron lone pair of nitrogen of pyridine and the pi electron cloud of the phenyl ring in 2-phenylpyridine fragment, 5.
Fig 4.
Comparison of the CEPs of 5, 8 and 9 with their corresponding charge-separated resonance forms.
Fig 5.
a) CEPs of several N-phenylpyrrole derivatives, b) Charge-separated resonance stabilization of 4-cyano-phenyl-pyrrole (11), c) CEPs of several N-pyridinepyrrole derivatives, d) Charge-separated resonance stabilization of 4-cyano-phenyl-pyrrole (14).
Fig 6.
CEPs of series of ortho-methyl substituted biphenyls (15–19) and how they compare with unsubstituted biphenyl, 1.
Fig 7.
CEPs of 2-alkylbiphenyls (ethyl, iso-propyl and tert-butyl, 20–22) and the comparison with biphenyl (1) and its methyl analogue (15).
Fig 8.
a) CEPs of a series of 2-halobiphenyls (23–26) and comparison with biphenyl 1 and 2-methylbiphenyl 15; b) Electrostatic fluorine—pi cloud aromatic ring attraction and repulsion.
Fig 9.
a) Comparison between CEPs of biphenyl and ortho substituted hydroxyl and methoxy derivatives, b) Diagram that represents the attractive interaction between the electrostatically positive hydrogen of the hydroxyl group and the negative pi cloud of the pendant phenyl ring, c) Comparison between CEPs of biphenyl and ortho substituted cyano and trifluoromethyl derivatives.
Fig 10.
Comparison between biphenyl 1, 2-phenylpyridine 5 and 2-(2-methylphenyl)-pyridine 31.
Fig 11.
a) CEPs of (6, 6)-pyridyl biaryls, b) CEPs of (5, 6)-pyridyl biaryls.
Fig 12.
a) Comparison between 2, 2’-bipyridyl (32) and 2-(2-fluorophenyl)pyridine (39), b) Comparison of CEPs between biphenyl systems with and without methyl or fluorine atoms in ortho positions (1, 17, 23, 40).
Fig 13.
a) Comparison between CEPs of structures containing a phenyl ring, 10 and 41, b) Comparison between CEPs of structures that contain a pyridine ring, 14 and 42, c) Comparison between CEPs of structures that contain a 2-fluoro-phenyl ring, 43 and 44.
Fig 14.
Aromatic carbonyl systems and table that indicates which figure each CEP is found in.
The dihedral angle being studied in each of the fragments is indicated with stars, with the orientation as drawn defining 0°.
Fig 15.
a) Comparison between CEPs of aryl acetyls, b) Comparison between CEPs of aryl primary amides.
Fig 16.
Effect of methylated amides in the CEP profile of benzamides 48, 51 and 52.
Fig 17.
a) Effect of methyl groups in benzamide 48, b) Effect of methyl groups in dimethylated amides 52, 55 and 56.
Fig 18.
Comparison between CEPs of N-aryl-acetamides.