Conformational control of -methyl-,′-diacylhydrazines by noncovalent carbon bonding in solution

In recent years, some X-ray structural and computational evidence has emerged for noncovalent carbon bonding (C-bond). However, evidence of C-bonds in solution is limited. Herein, from the conformational analyses of strategically designed N -methyl- N , N ′-diacylhydrazines, we for the first time show that C-bonds can be modulated to control the conformational preferences of small molecules in solution. We show that unusual N(amide) C-X noncovalent carbon bonding interactions stabilize the trans - cis ( t - c ) amide bond rotamers of N -methyl- N , N ′-diacylhydrazines over the expected trans - trans ( t - t ) rotamers. Unusual N(amide) C-X noncovalent carbon bonding interactions stabilize the trans - cis ( t - c ) amide bond rotamers of N -methyl- N , N ′-diacylhydrazines over the expected trans - trans ( t - t ) rotamers in solution.