Synthesis and magnetic properties of manganese carbonyl complexes with different coordination modes of 3,4,5-triaryl-1,2-diphospholide ligands

Abstract

The set of complexes bis-(μ:η¹,η¹-3,4,5-triaryl-1,2-diphosphacyclopentadienyl)-bis-(tetracarbonyl manganese(I)) (aryl = C₆H₅ (2a), p-FC₆H₄ (2b), p-ClC₆H₄ (2c)) undergo an irreversible rearrangement to mononuclear 3,4,5-triaryl-1,2-diphosphacymantrenes (3a–c). According to quantum-chemical calculations binuclear complexes 2 can be considered to be products of kinetic control and mononuclear species 3 are thermodynamically favorable compounds. The antiferromagnetic intramolecular interaction observed for complexes 2 can be effectively tuned by using substituents in the para-position of the arene ring, whereas mononuclear 1,2-diphosphacymantrenes 3 are diamagnetic.