Mono-and homodi-nuclear copper(i1) complexes of macrocyclic Schiffbases derived from the condensation of pyrrole -2,5-d icar balde h yde and a,O-a I kaned iamines are reported. The crystal structure of the mononuclear complex (3,7,14,18,23,24-hexa-azatricyclo [ 18.2.1.1 '*"] tetracosane-2,7,9,11,13,18,20,22-0ctaene-N~,N~,N~~,N~~)copper( 11) has been determined. Crystals are orthorhombic, of space group Pbcn (D::, no. 60), with a = 11.701 (9), b = 13.702(9), c = 1 0.600(6) A, and 2 = 4.557 Independent reflections with l / o ( / ) > 3.0 gave R = 0.051 8. The copper(ti) atom is sited at one end of the macrocycle where it is bonded to two pyrrole and two imino nitrogen atoms in a co-ordination geometry having a 30.3" tetrahedral distortion from square planar. The pyrrole-dicarbimine fragments adopt cis-trans conformations. The crystal structure of pyrrole-2,5-dicarbaldehyde has also been determined. Crystals are monoclinic, of space group Pn (a non-standard setting of Pc; q, no. 7), with a = 3.81 66( 6), b = 14.637(3), c = 20.755(5) A, p = 91.665( 16)", and 2 = 8. 1 876 Independent reflections with IFl/o(lFl) > 3.0 gave R = 0.0449.The synthesis of metal complexes of '2 + 2' tetraimine Schiff-

The macrocyclic polyether 18-crown-6 (C, 2H2406) readily forms crystalline 1 : 1 complexes with the adducts BF3NH3 and BH3NH3. Crystals of the solvates BF3N.H3C,2H2406CH2C12 and BH3NH3C12H2,06*MeOH were suitable for X-ray crystallographic investigation. In both cases, the crystal structures reveal that 18-crown-6 adopts an all-gauche conformation with pseudo D3d symmetry in which the intermolecular N-H * -0 hydrogen-bonding interactions between the macrocyclic polyether and the adducts are associated directly with the triangle of oxygen atoms on the complexing face of the crown.

Dinucleating macrocyclic Schiff bases derived from the condensation of thiophene-2,5-dicarbaldehyde and a number of a,o-alkanediamines are reported together with their barium and silver complexes.

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