Is a wrongdoer obligated to do anything if he intended and articulated (to himself) that he would financially compensate the one he wronged, and then wished to retract that?

It is not permissible to harm people in the first place, even if the one who wrongs intends to seek forgiveness for his wrongdoing, because he may not be forgiven or death may not grant him respite. Whoever has wronged should seek forgiveness by asking for pardon; otherwise, he should pray for the wronged person and speak well of him in the gathering where he committed the wrong. As for the intention to give charity to someone one has wronged and then retracting that intention, there is no sin in it, and he is not obligated to carry it out.