STRUCTURAL AND SPECTROSCOPIC STUDIES ON 36-MEMBERED RING ARRAYS FORMED BY COPPER(II) HALIDES WITH 1-(4-PICOLYL)PYRROLIDIN-2-ONE

Reaction of 1-(4-picolyl)pyrrolidin-2-one (ppo) with hydrated copper(I I) chloride or bromide in methanol affords the compounds [Cu(ppo)(2)X( 2)] (X = Cl or Br). A single-crystal X-ray diffraction study of [Cu(pp o)(2)Br-2] 1 shows that the ppo molecule acts asa bridging ligand with the formation of all trans-CuBr2N2O2 units linked to produce sheets o f contiguous 36-membered rings. The EPR spectra of 1 and its chloride analogue give well resolved rhombic-type spectra. The EPR and electron ic spectra of [Cu(ppo)(2)X(2)] (X = Cl or Br) are analysed in terms of angular-overlap bonding parameters. X-Ray studies show that the compo und [Cu4OCl6(ppo)(4)] comprises a Cu-4(mu(4)-O)Cl-6 core with an N-bon ded ppo ligand co-ordinated to each Cu atom.