Hydrogen bonding, dielectric effects, and steric effects are all factors which determine the carbonyl stretching frequency, vC=O, of ketones in solution. The vC=O frequency for ketones shifts continuously at constant concentration in solutions of CHCl3/CCl4 with change in the mole ratio of the two solvents. The vC=O frequency is also affected by change in concentration in either CCl4 or CHCl3 solution.
R. A. Nyquist, C. L. Putzig, and L. Yurga, "Solvent and Concentration Effects on Carbonyl Stretching Frequencies: Ketones," Appl. Spectrosc. 43, 983-991 (1989)