The reaction of 0.67 molar equivalents of the O,N,O'-tridentate zwitterionic Schiff base (2Z,4E)-4-[(2-hydroxyphenyl)iminio]pent-2-en-2-olate (H2L) with one equivalent of zinc(II) acetate in methanol affords a novel trinuclear Zn(II) cluster, di-mu-acetato-1:2kappa2O:O';2:3kappa2O:O'-dimethanol-1kappaO,3kappaO-bis{mu-2-[(2E,3Z)-4-oxidopent-3-en-2-ylideneamino]phenolato}-1:2kappa4O2,N,O4:O4;2:3kappa4O4:O2,N,O4-trizinc(II), [Zn3(C11H11NO2)2(C2H3O2)2(CH4O)2], (I), in which two bridging acetate ligands link the terminal square-based pyramidal Zn(II) ions to the approximately tetrahedral Zn(II) ion at the core of the cluster. The ZnO(4) coordination group of the central Zn(II) ion is established by two bridging phenolate and two bridging acetate O atoms. The remaining four coordination sites of each terminal Zn(II) ion are occupied by methanol and deprotonated H2L. Furthermore, the Zn-bound methanol hydroxyl groups are involved in complementary hydrogen bonding with the Zn-bound enolate O atom of a neighbouring molecule, about an inversion centre in each case. The structure of (I) is therefore best described as an extended one-dimensional hydrogen-bonded chain of trinuclear Zn(II) clusters.

When {2,2'-[(2-methyl-2-nitropropane-1,3-diyl)diimino]diacetato}copper(II), [Cu(C(8)H(13)N(3)O(6))], (I), was crystallized from a binary mixture of methanol and water, a monoclinic two-dimensional water- and methanol-solvated metal-organic framework (MOF) structure, distinctly different from the known orthorhombic one-dimensional coordination polymer of (I), was isolated, namely catena-poly[[copper(II)-mu(3)-2,2'-[(2-methyl-2-nitropropane-1,3-diyl)diimino]diacetato] methanol 0.45-solvate 0.55-hydrate], {[Cu(C(8)H(13)N(3)O(6))].0.45CH(3)OH.0.55H(2)O}(n), (II). The monoclinic structure of (II) comprises centrosymmetric dimers stabilized by a dative covalent Cu(2)O(2) core and intramolecular N-H...O hydrogen bonds. Each dimer is linked to four neighbouring dimers via symmetry-related (opposing) pairs of bridging carboxylate O atoms to generate a ;diamondoid' net or two-dimensional coordination network. Tight voids of 166 A(3) are located between these two-dimensional MOF sheets and contain a mixture of water and methanol with fractional occupancies of 0.55 and 0.45, respectively. The two-dimensional MOF sheets have nanometre-scale spacings (11.2 A) in the crystal structure. Hydrogen-bonding between the methanol/water hydroxy groups and a Cu-bound bridging carboxylate O atom apparently negates thermal desolvation of the structure below 358 K in an uncrushed crystal of (II).