What is the ruling on saying, "Give me my things and you are divorced," with the intention of taking the things and not with the intention of divorce, especially given that the wife was menstruating at that time?

The phrase "You are divorced" is an explicit pronouncement of divorce, and divorce takes effect with it, even if you did not intend it. Divorce during menstruation is an innovated divorce (bid'i), but the preponderant opinion is that it takes effect. If this pronouncement was not the third, you are permitted to take your wife back, and it is recommended to have witnesses to the return. It is not permissible for a woman to seek divorce except for a legitimate Shar'i reason. Spouses should understand each other and resolve their problems away from divorce, especially when children are involved.