Crystal structures and theoretical investigation of anti-/syn-2,4-diphenylpentane- and 2,4-di-p-tolylpentane-2,4-diols

• Published in: Journal of Central South University Vol. 19; no. 5; pp. 1219 - 1225
• Main Authors: Jiao, Yin-chun, Cao, Chen-zhong, Zhao, Xiao-lin
• Format: Journal Article
• Language: English
• Published: Heidelberg Central South University 01.05.2012
• Subjects: Engineering; Metallic Materials; X-ray crystallography; solvent effect; UV-vis absorption; hydrogen bonds; nuclear magnetic resonance (NMR); density function theory (DFT)
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-012-1132-0

2,4-diphenylpentane- and 2,4-di- p -tolylpentane-2,4-diols were investigated employing experimental and density functional theory (DFT) method at B3LYP/6-31G (d) level. The structure of syn-2,4-di- p -tolylpentane-2,4-diol (2b) was characterized by X-ray diffraction and compared with the crystal structures of anti- and syn-2,4-diphenylpentane-2,4-diols (1a and 1b). X-ray diffraction indicates that inter and intra-molecular hydrogen bonds are formed in the crystal structures. There is π-π staking interaction in 1b and 2b. Good linear correlations and similar results are found between the experimental 1 H and 13 C NMR chemical shifts ( δ exp ) and GIAO (Gauge Independent Atomic Orbital) method calculated magnetic isotropic shielding tensors ( δ calc ). HOMO and LUMO molecular orbitals were calculated at the same levels with the different results. UV-vis absorption spectra of the compounds were recorded in EtOH, MeCN, n -BuOH and cyclohexane with different dielectric constants. It is found that the solvent effect is obvious when ɛ is 24.85(EtOH), 35.69(MeCN) and it is weak when ɛ is decreased to 17.33( n -BuOH), 1.18 (cyclohexane).