Tris(N-{bis­[meth­yl(phen­yl)amino]­phosphor­yl}benzene­sulfonamidato-κ2O,O′)(1,10-phenanthroline-κ2N,N′)lanthanum(III)

The asymmetric unit of [La(C20H21N3O3PS)3(C12H8N2)] is created by one LaIII ion, three deprotonated N-{bis­[meth­yl(phen­yl)amino]­phosphor­yl}benzene­sulfonamidate (L−) ligands and one 1,10-phenanthroline (Phen) mol­ecule. Each LaIII ion is eight-coordinated (6O+2N) by three phosphoryl O atoms, three sulfonyl O atoms of three L− ligands and two N atoms of the chelating Phen ligand, leading to the formation of six- and five-membered metallacycles, respectively. The lanthanum coordination polyhedron has a bicapped trigonal–prismatic geometry. `Sandwich-like' intra­molecular π–π stacking inter­actions are observed between the 1,10-phenanthroline ligand and two benzene rings of two different L− ligands. The phenyl rings of L− that are not involved in the stacking inter­actions show minor positional disorder. Mol­ecules form layers parallel to the (010) plane due to weak C—H⋯O inter­molecular hydrogen bonds. Unidentified highly disordered solvate mol­ecules that occupy ca 400 A3 large voids have been omitted from the refinement model.