1.Qxc4+ Kd7  and now there are several alternatives to be played out.  I am not sure white has a guaranteed win.  The black king now has an escape square.  He is also in position to "protect" an inteposing queen at e6 and he still "protects" his d8 rook (though he can't do both, so I think he will use the e7 escape square before interposing his queen).  I think he has a pretty good answer for white's next move, whatever it is.

Edit - but white still has a huge material advantage, and he'll probably bring his additional rook and knight into action to finally win the game.