Solvent influence on the conformational equilibrium of 2,2′-bipyridine

Structural and Photophysical Properties of Various Polypyridyl Ligands: A Combined Experimental and Computational Study

“…This is in agreement with the findings of Ref. [45] where the authors report an increase of the dipole moment when e r increases. The larger dipole moment is attributed to a higher population of the dipolar cis structure.…”

“…The conformational equilibrium is determined by conjugation of the two pÀ systems, steric hindrance by the hydrogen atoms and electrostatic interactions. [29,45] The trans conformer is predicted to be lower in energy than the cis conformer. The reason for this is that the repulsive interaction between the lone-pair electrons of the nitrogen atoms is smaller than the attractive interactions between a nitrogen and a hydrogen atom situated on different rings.…”

Sodium adduct formation efficiency in ESI source

“…Nevertheless, the situation with nitrogen bases is more complex: the 2‐ and/or 6 substituted amino‐ and methoxypyridines do not give sodium adducts signal in MS spectra, in spite of their chelating abilities demonstrated by the COSMO‐RS calculations. For 2,2‐bipyridine, computational and experimental evidence from the literature as well as computational evidence from this work suggest that trans conformer is much more stable than the cis conformer. The difference of the conformer stabilities in the solvent used in this work was found to be 2.4 kcal mol ‐1 (calculated with COSMO‐RS).…”

Physical Nature of Interactions in ZnIIComplexes with 2,2′-Bipyridyl: Quantum Theory of Atoms in Molecules (QTAIM), Interacting Quantum Atoms (IQA), Noncovalent Interactions (NCI), and Extended Transition State Coupled with Natural Orbitals for Chemical Valence (ETS-NOCV) Comparative Studies

“…[2][3][4] Knowledge of the conformational structure of -diimine ligands and information about the rotational energy barrier are important and useful for a better understanding of the complex formation process and trends in stability of complexes. Hence not surprisingly, these ligands have also been extensively studied computationally [5][6][7][8][9][10][11][12][13][14][15][16][17][18] and for over 40 years it is known that the most stable conformer of 2,2-bipyridyl has two N-atoms trans to each other (s-trans conformer). [9][10][11][12][13][14][15] Lower stability of the conformer with nitrogens cis to each other (s-cis conformer) was attributed mainly to the steric hindrance of the 3,3-hydrogen atoms and destabilizing nitrogen lone pair-lone pair interactions [11][12][13][14][15][16][17] in 2,2-bipyridyl.…”

“…Moreover, metal complexes of bpy have been investigated for the purpose of solar energy devices, energy storages, or possible nonlinear optical materials. − Knowledge of the conformational structure of α-diimine ligands and information about the rotational energy barrier are important and useful for a better understanding of the complex formation process and trends in the stability of complexes. Hence, not surprisingly, these ligands have also been extensively studied computationally − and for over 40 years it is known that the most stable conformer of 2,2′-bipyridyl has two N-atoms trans to each other (s-trans conformer). − The lower stability of the conformer with nitrogens cis to each other (s-cis conformer) was attributed mainly to the steric hindrance of the 3,3′-hydrogen atoms and destabilizing nitrogen lone pair-lone pair interactions − in 2,2′-bipyridyl. To act as a chelate, this ligand must, however, attain the s-cis conformation resulting in the 3,3′-hydrogen atoms being in the close contact, CH--HC (Figure ).…”