Structural, spectroscopic and theoretical studies of dimethylphenyl betaine complex with two molecules of 2,6-dichloro-4-nitro-phenol

• Dimethylphenyl betaine crystallizes with two molecules of 2,6-dichloro-4-nitro-phenol.
• Molecules are linked by two different OH⋯O hydrogen bonds without the proton transfer.
• The structures in crystal, gas phase and DMSO solution are analyzed.
• The experimental and calculated frequencies have been assigned.
• The magnetic isotropic shielding constants reproduce the experimental chemical shifts.

The 1:2 complex (1) of dimethylphenyl betaine (DMPB) with two molecules of 2,6-dichloro-4-nitro-phenol (DCNP) was prepared and characterized by X-ray diffraction, B3LYP/6-311++G(d,p) and B3LYP-D3/6-311++G(d,p)calculations, FTIR and NMR spectroscopies. The crystal is monoclinic, space group P21/c with Z = 4. The protons at the oxygen atoms of phenols are bonded to each oxygen atoms of the DMPB carboxylate group by two nonequivalent H-bonds with the OH⋯O distances of 2.473(5) and 2.688(4) Å. Both H-bonds in the optimized structures 2 (in vacuum), 3 (in DMSO solution) and dispersion-correlated functional (D3) 4 (in vacuum) are comparable and are slightly shorter than O(6)H(O6)⋯O(2) in the crystal. The FTIR spectrum of 1 shows a broad absorption in the 3400–2000 cm−1 region corresponding to a longer hydrogen bond and a broad absorption in the 1800–500 cm−1 region caused by the shorter H-bond. The relations between the experimental 13C and 1H chemical shifts (δexp) of the investigated compound 1 in DMSO solution and GIAO/B3LYP/6-311++G(d,p) magnetic isotropic shielding constants (σcalc) obtained by using the screening solvation model (COSMO) for 3 are linear and reproduce well the experimental chemical shifts described by the equation: δexp = a + b σcalc.

The 1:2 complex of dimethylphenyl betaine with two molecules of 2,6-dichloro-4-nitro-phenol was prepared and investigated by X-ray diffraction, B3LYP/6-311++G(d,p) and B3LYP-D3/6-311++G(d,p) calculations, FTIR and NMR spectroscopies. Phenols are bonded to each oxygen atoms of COO− group of the betaine by two nonequivalent O⋯HO hydrogen bonds of 2.473(5) and 2.688(4) Å.Figure optionsDownload as PowerPoint slide