Spectroscopic and theoretical studies of some 2‑(methoxy)‑2‑[(4‑substituted)‑phenylsulfanyl]‑(4'‑substituted) acetophenones.

The conformational analysis of some 2‑(methoxy)‑2‑[(4‑substituted)‑phenylsulfanyl]‑(4'‑substituted) acetophenones was performed through infrared (IR) spectroscopic analysis of the carbonyl stretching band (ν), supported by B3LYP/6-31+G(d,p) calculations and X-ray diffraction. Five (1-5) of the seven studied compounds (1-7) presented Fermi resonance (FR) on the ν fundamental transition band. Deuteration of these compounds (1a-5a) precluded the occurrence of FR, revealing a ν doublet for all compounds in all solvents used.

Crystal structure of 2-meth-oxy-2-[(4-meth-oxy-phen-yl)sulfan-yl]-1-phenyl-ethanone.

In the title β-thio-carbonyl compound, C16H16O3S, the adjacent meth-oxy and carbonyl O atoms are synperiplanar [the O-C-C-O torsion angle is 19.8 (4)°] and are separated by 2.582 (3) Å.

Crystal structure of 2-meth-oxy-2-[(4-methyl-phen-yl)sulfan-yl]-1-phenyl-ethan-1-one.

In the title β-thio-carbonyl compound, C16H16O2S, the carbonyl and meth-oxy O atoms are approximately coplanar [O-C-C-O torsion angle = -18.2 (5)°] and syn to each other, and the tolyl ring is orientated to lie over them. The dihedral angle between the planes of the two rings is 44.