Study of a New Proton Transfer Compound: Bis (2,9-dimethyl-1,10-phenantrolinium) hydrogen (S,S) tartrate nonahydrate by Ab Initio Calculations

A new proton transfer compound of 2, 9-dimethyl-1, 10-phenantroline and d-tartaric acid was synthesized and studied by using DFT and ab initio HF methods. The chemical formulas for the proton transfer ion pair is (dmpH) ₂⁺ (d-tartH) ₂^–.9H₂O, where dmp = 2, 9-dimethyl-1, 10-phenantroline and d-tartH₂ = d-tartaric acid. In this crystal structure, d-hydrogen tartrate anions are joined together in a head-to-tail fashion via short hydrogen. A number of intermolecular O–H···O, N-H···O and C–H···O hydrogen bonding interactions, as well as π–π stacking, play important roles in this crystal structure. The geometrical parameters of (dmpH)₂⁺(d-tartH)₂^– , 9H₂Oion pair have been optimazed with the B3LYP method of density functional theory (DFT) and ab initio Hartree-Fock (HF) methods for comparison. Theoretical calculations confirm a number of intermolecular O–H···O, N-H···O and C–H···O hydrogen bonding interactions, as well as π–π stacking, play important roles in this crystal structure.