Octanuclear and Nonanuclear Supramolecular Copper(II) Complexes with Linear “Tritopic” Ligands: Structural and Magnetic Studies

The structures and magnetic properties of self-assembled copper(II) clusters and grids with the “tritopic” ligands 2poap (a), Cl2poap (b), m2poap (c), Cl2pomp (d), and 2pomp (e) are described [ligands derived by reaction of 4-R-2,6-pyridinedicarboxylic hydrazide (R = H, Cl, MeO) with 2-pyridinemethylimidate (a−c, respectively) or 2-acetylpyridine (d, R = Cl; e, R = H)]. Cl2poap and Cl2pomp self-assemble with Cu(NO3)2 to form octanuclear “pinwheel” cluster complexes [Cu8(Cl2poap-2H)4(NO3)8]·20H2O (1) and [Cu8(Cl2pomp-2H)4(NO3)8]·15H2O (2), built on a square [2 × 2] grid with four pendant copper arms, using “mild” reaction conditions. Similar reactions of Cl2pomp and 2pomp with Cu(ClO4)2 produce pinwheel clusters [Cu8(Cl2pomp-2H)4(H2O)8](ClO4)8·7H2O (3) and [Cu8(2pomp-2H)4(H2O)8](ClO4)8 (4), respectively. Heating a solution of 1 in MeOH/H2O produces a [3 × 3] nonanuclear square grid complex, [Cu9(Cl2poap-H)3(Cl2poap-2H)3](NO3)9·18H2O (5), which is also produced by direct reaction of the ligand and metal sal...