Structure of Amido-Pyridinium Betaines: Persistent Intermolecular C-H•••N Hydrogen Bonding in Solution

TY - JOUR

T1 - Structure of Amido-Pyridinium Betaines

T2 - Persistent Intermolecular C-H•••N Hydrogen Bonding in Solution

AU - Thatcher, Robert James

AU - Johnson, David Grahame

AU - Slattery, John Martin

AU - Douthwaite, Richard E

N1 - . © 2016, Wiley-VCH. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

PY - 2016/3/1

Y1 - 2016/3/1

N2 - A hydrogen bond of the type C-H⋯X (X=O or N) is known to influence the structure and function of chemical and biological systems in solution. C-H⋯O hydrogen bonding in solution has been extensively studied, both experimentally and computationally, whereas the equivalent thermodynamic parameters have not been enumerated experimentally for C-H⋯N hydrogen bonds. This is, in part, due to the lack of systems that exhibit persistent C-H⋯N hydrogen bonds in solution. Herein, a class of molecule based on a biologically active norharman motif that exhibits unsupported intermolecular C-H⋯N hydrogen bonds in solution has been described. A pairwise interaction leads to dimerisation to give bond strengths of about 7 kJ mol-1 per hydrogen bond, which is similar to chemically and biologically relevant C-H⋯O hydrogen bonding. The experimental data is supported by computational work, which provides additional insight into the hydrogen bonding by consideration of electrostatic and orbital interactions and allowed a comparison between calculated and extrapolated NMR chemical shifts.

AB - A hydrogen bond of the type C-H⋯X (X=O or N) is known to influence the structure and function of chemical and biological systems in solution. C-H⋯O hydrogen bonding in solution has been extensively studied, both experimentally and computationally, whereas the equivalent thermodynamic parameters have not been enumerated experimentally for C-H⋯N hydrogen bonds. This is, in part, due to the lack of systems that exhibit persistent C-H⋯N hydrogen bonds in solution. Herein, a class of molecule based on a biologically active norharman motif that exhibits unsupported intermolecular C-H⋯N hydrogen bonds in solution has been described. A pairwise interaction leads to dimerisation to give bond strengths of about 7 kJ mol-1 per hydrogen bond, which is similar to chemically and biologically relevant C-H⋯O hydrogen bonding. The experimental data is supported by computational work, which provides additional insight into the hydrogen bonding by consideration of electrostatic and orbital interactions and allowed a comparison between calculated and extrapolated NMR chemical shifts.

KW - aggregation

KW - betaines

KW - bond energy

KW - hydrogen bonds

KW - nitrogen heterocycles

UR - http://www.scopus.com/inward/record.url?scp=84959161123&partnerID=8YFLogxK

U2 - 10.1002/chem.201503884

DO - 10.1002/chem.201503884

M3 - Article

SN - 0947-6539

VL - 22

SP - 3414

EP - 3421

JO - Chemistry : A European Journal

JF - Chemistry : A European Journal

IS - 10

ER -