The macrocyclic hexanuclear metal cluster, [Mn(III)(6)(fshz)(6)S(6)], 1 (S = MeOH), was prepared using a trianionic pentadentate ligand, N-formylsalicylhydrazidate (fshz(3)(-)). Due to the meridional coordination of the ligand to the metal ion, the ligand is not only bridging the ring metal ions using a hydrazide N-N group but also enforcing the stereochemistry of the metal ions as a propeller configuration. The alternations of the chiralities of the metal centers expand the cyclic ring system of complex 1 to the 24-membered ring system. The neutral hexanuclear manganese complex with noncrystallographic pseudo-C(3)(i)() symmetry is in the crystallographic inversion center. The disc-shaped hexanuclear cluster is 1.8 nm in diameter and 0.8 nm in thickness and has a vacant cavity in the center of the cluster. Three solvent molecules coordinated at the metal centers with Lambda configuration are in one face of the cluster, and the remaining three solvent molecules coordinated at the other metal centers with Delta configuration are in the other face of the cluster. The two faces of the cluster have opposite chiralities to each other. The crystal packing structure of complex 1 shows that the disc-shaped hexanuclear clusters are aligned approximately along the crystallographic a axis. The cavities of the clusters in the crystal structure are also aligned, and one-dimensional channels are formed. The solution integrity of the cluster was addressed using solution mass spectrometry, paramagnetically shifted (1)H NMR spectroscopy, and UV-visible spectroscopy. Crystallographic data for 1: triclinic, P&onemacr;, a = 10.0237(9) Å, b = 15.096(1) Å, c = 15.617(1) Å, alpha = 112.142(5) degrees, beta = 106.615(5) degrees, gamma = 99.958(7) degrees, V = 1989.8(3) Å(3), Z = 2, D(calcd) = 1.510 g cm(-)(1), R1 = 0.0502 and wR2 = 0.1424 for 4249 reflections with I > 2sigma(I), GOF = 1.065.

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We are reporting a novel azo-azomethine ligand, HL and its complexes with Cu(II) and Fe(III) ions. The ligand and its complexes are characterized by various physico-chemical techniques using C,H,N analyses, FT-IR, 1H-NMR, ESI-MS and UV-Vis studies. TGA analyses reveal complexes are sufficiently stable and undergo two-step degradation processes. The redox behavior of the complexes was evaluated by cyclic voltammetry. Furthermore, the ligand and its complexes were tested for antimicrobial activity against bacterial and fungal strains by determining inhibition zone, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The complexes showed moderate antimicrobial activity when tested against Gram +ve and Gram −ve bacterial strains. To obtain insights into the structure of ligand, DFT studies are recorded. The results obtained are quite close to the experimental results. In addition, the energy gap, chemical hardness, softness, electronegativity, electrophilic index and chemical potential were calculated using HOMO, LUMO energy value of ligand.