In this work we investigate the interaction between dark matter and dark energy for a coupling that obeys the Wang–Meng decaying law, $$\rho _{\mathrm{DM}}\propto (1+z)^{3-\epsilon }$$ ρ DM ∝ ( 1 + z ) 3 - ϵ , and the Barboza–Alcaniz dark energy parametric model, $$w=w_0+w'_0z(1+z)/(1+z^2)$$ w = w 0 + w 0 ′ z ( 1 + z ) / ( 1 + z 2 ) . Theoretically, we show that the coupling constant, $$\epsilon $$ ϵ , should satisfy the physical constraint $$\epsilon \ge 0$$ ϵ ≥ 0 . We use the most recent data of type Ia supernovae, baryon acoustic oscillations, cosmic microwave background and the Hubble expansion rate function to constrain the free parameters of the model. From a purely observational point of view, we show that is not possible to discard values of the coupling constant in the unphysical region $$\epsilon <0$$ ϵ < 0 . We show that the uncoupled case, $$\epsilon =0$$ ϵ = 0 , is in better agreement with the data than any of coupled models in the physical region. We also find that all physically acceptable interaction in dark sector lies in the narrow range $$0<\epsilon \le 0.034$$ 0 < ϵ ≤ 0.034 (95 % CL).