The present invention relates to a cell-targeting complex comprising a targeting moiety and a deliverable compound, wherein said targeting moiety and said deliverable compound are joined by means of a (transition) metal ion complex having at least a first reactive moiety for forming a coordination bond with a reactive site of said targeting moiety and having at least a second reactive moiety for forming a coordination bond with a reactive site of said deliverable compound, and wherein said deliverable compound is a therapeutic compound.