Self-assembly of Schiff-base palladacycle-based discrete pseudo-macrocycles: Evidence for hemilability of oxalate ligand

• Synthesis of oxalato bridged binuclear Schiff-base palladacycles.
• Self-assembly of discrete pseudo-macrocycles with 1,1′-bicoordinated oxalato bridge.
• Unusual bidentate/monodentate tri-coordinated oxalato bridged Schiff-base palladacycle.

Bis-bidentate tetra-coordinated oxalato bridged binuclear Schiff-base palladacycles [Pd{C,N-κ2-(4-R)C6H3CHNC6H3-2,6-i-Pr2]2(μ-η2-η2-C2O4) (R = H; OMe) were synthesized. Reactions of μ-oxalato bridged Schiff-base palladacycles [Pd{C,N-κ2-(4-R)C6H3CHNC6H3-2,6-i-Pr2]2(μ-η2-η2-C2O4) (R = H; OMe) with 1,4-bis(diphenylphosphino)butane (dppb) and 1,4-bis(diphenylphosphino)pentane (dppp) generated discrete pseudo-macrocycles with 1,1′-bicoordinated oxalato bridge. Unexpectedly, μ-oxalato bridged Schiff-base palladacycle [Pd(C,N-κ2-C6H4CHNC6H3-2,6-i-Pr2)]2(μ-η2-η2-C2O4) reacted with PPh3 to form unusual bidentate/monodentate tri-coordinated oxalato bridged binuclear cyclopalladated complex [Pd(C,N-κ2-C6H4CHNC6H3-2,6-i-Pr2)(PPh3)](μ-η2-η1-C2O4)[Pd(C-κ1-C6H4CHNC6H3-2,6-i-Pr2)(PPh3)].

Bis-bidentate tetra-coordinated oxalato bridged binuclear Schiff-base palladacycles were synthesized. Self-assembly of discrete pseudo-macrocycles with 1,1′-bicoordinated oxalato bridge was studied. Tetra-coordinated oxalato bridged binuclear Schiff-base palladacycle reacted with triphenylphosphine to form unusual bidentate/monodentate tri-coordinated oxalato bridged Schiff-base palladacycle.Figure optionsDownload as PowerPoint slide