Formation of very large rings in polymeric lanthanide complexes of N,N'-p-phenylenedimethylenebis(pyrrolidin-2-one)

The synthesis is reported of N,N'-p-phenylenedimethyrenebis(pyrrolidin (p-XBPYR), a range of lanthanide (Ln) complexes of types Ln(2)(NO3)(p-XBPYR)(3) and Ln(p-XBPYR)(3)(ClO4)(3)(H2O)(3), and the compounds Y-2(NO3)(6)(p-XBPYR)(3) and Pr(pXBPYR)(3)(ClO4)(3) . 0.5(CH3CN). Single crystal X-ray diffraction studies show that crystals of [Tb-2(NO3)(6)(p-XBPYR)(3)] are triclinic, space group <P(1)over bar>, a=8.624(2), b=9.558(2), c=18.294(3) Angstrom, alpha=85.15(2), beta=86.76(2), gamma=81.18(2)degrees, Z=2. The p-XBPYR ligands again bridge the centres so as to form sheets of contiguous 78-membered rings. Crystals of Pr(p-XBPYR)(3) .(ClO4)(3) . 0.5(CH3CN) are monoclinic, space group p2/n, a=14.063(1), b=11.500(1), c=18.388(1) Angstrom, beta=91.10(2)degrees, Z=2. The p-XBPYR ligands again bridge the metal centres but in this case a complex array of 52- and 26-membered rings is formed. Each Pr atom has a bidentate perchlorate group bonded to it, but the other perchlorates are present as anions in the lattice.