Tris(N-{bis-[meth-yl(phen-yl)amino]-phosphor-yl}benzene-sulfonamidato-κ(2)O,O')(1,10-phenanthroline-κ(2)N,N')lanthanum(III).

The asymmetric unit of [La(C(20)H(21)N(3)O(3)PS)(3)(C(12)H(8)N(2))] is created by one La(III) ion, three deprotonated N-{bis-[meth-yl(phen-yl)amino]-phosphor-yl}benzene-sulfonamidate (L(-)) ligands and one 1,10-phenanthroline (Phen) mol-ecule. Each La(III) 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' intra-molecular π-π stacking inter-actions 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 inter-actions show minor positional disorder. Mol-ecules form layers parallel to the (010) plane due to weak C-H⋯O inter-molecular hydrogen bonds. Unidentified highly disordered solvate mol-ecules that occupy ca 400†à (3) large voids have been omitted from the refinement model.