Force field parameters for N,N-Dimethylformamide (DMF) revisited: Improved prediction of bulk properties and complete miscibility in water

A partial negative charge on the nitrogen atom in N,N-Dimethylformamide (DMF), as employed in all force fields, leads to the separation of water and DMF phases. Hence, based on the possibility of the existence of dual resonance structures for DMF and of the presence of a reverse carbon-nitrogen dative bond, we reparameterized DMF and demonstrate that a positively charged nitrogen atom is imperative to achieve complete DMF-water miscibility. The reversal of the charge results in enhanced water-DMF interactions. Significant improvement in the predicted bulk properties of DMF is also observed. New parameters were benchmarked using ab-initio molecular dynamics. (C) 2015 Elsevier B.V. All rights reserved.