I have said it in other posts as well that January transfer will not be beneficial for both the clubs. Coutinho is cup tied in the Champions League as he has played for the Liverpool already. In La Liga Barcelona is way ahead of other teams. So a player for only Copa del rey would not suit Barcelona. On the other hand, he could help liverpool with top 4 finish as well as advancing deep into the Champions League knockout stages. Rumours were also there during the summer transfer window, But Klopp is very determined when coming to a decision. So wait till next season, he is not going anywhere.