Bis[μ-bis(2,6-diisopropylphenyl) phosphato-κ2O: O ′]bis[(2,2′-bipyridine-κ2N, N ′)lithium] toluene disolvate and its catalytic activity in ring-opening polymerization of -caprolactone and l -dilactide

Abstract

The solvated centrosymmmtric title compound, [Li2(C24 H34 O4 P)2 (C10 H8 N2)2 ]·2C 7 H8, was formed in the reaction between {Li[(2,6- i Pr2C6 H3-O)2 POO](MeOH)3}(MeOH) and 2,2′-bipyridine (bipy) in toluene. The structure has monoclinic (P2 1 /n) symmetry at 120 K and the asymmetric unit consists of half a complex molecule and one molecule of toluene solvent. The diaryl phosphate ligand demonstrates a μ-κO:κO′-bridging coordination mode and the 2,2′-bipyridine ligand is chelating to the Li + cation, generating a distorted tetrahedral LiN2 O2coordination polyhedron. The complex exhibits a unique dimeric Li2O4 P2core. One isopropyl group is disordered over two orientations in a 0.621 (4):0.379 (4) ratio. In the crystal, weak C - H...O and C - H...π interactions help to consolidate the packing. Catalytic systems based on the title complex and on the closely related complex {Li[(2,6- i Pr2C6 H3-O)2 POO](MeOH)3}(MeOH) display activity in the ring-opening polymerization of -caprolactone and l-dilactide.