Samarium versus aluminium Lewis acidity in a mixed alkyl carboxylate complex related to alkylaluminium activation in diene polymerization catalysis

[(C5Me5)2Sm((mu)-O2CPh)]2 reacts with iBu3Al to form a mixed bridge samarium aluminium complex [(C5Me5)2Sm((mu)-O2CPh) ((mu)-iBu)Al(iBu)2], that displays two different carboxylate orientations toward the metals in a single crystal.