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The synthesis and characterization of hexanuclear, octanuclear, and decanuclear manganese metalladiazamacrocycles of a series of pentadentate ligands with systematically controlled beta-branched N-acylsalicylhydrazides and alpha-branched N-acylsalicylhydrazides are reported. The results show that the size and shape of the substituents influence the nuclearity and the features of metalladiazamacrocycles because close contacts are occurring between the N-acyl substituents.

A trinuclear copper complex [Cu3(napxshz)2(phen)2] has been synthesised using a tribasic naproxen‐appended ligand [H3napxshz = 2‐hydroxy‐N′‐(2‐[6‐methoxynaphthalen‐2‐yl] propanoyl) benzohydrazide] and 1,10‐phenanthroline. The complex was characterised by different spectroscopic methods such as Fouriertransform infrared (FT‐IR), ultraviolet‐visible (UV–Vis) and electrospray ionisation (ESI)‐mass spectroscopy. The solid‐state structure of the ligand and complex 1 was established by single‐crystal X‐ray diffraction analysis. The interaction of the complex and the ligand with DNA was investigated by UV–visible spectroscopy and fluorometric titrations. The calculated binding constants (Kb) of the complex and the ligand with ct‐DNA show that the complex has a higher binding affinity than the ligand H3napxshz. Quantum chemical calculations were performed to understand the structural aspects of the complex and its interactions with DNA. The molecular docking study reveals the interaction between DNA, and the complex is in intercalative mode. [ABSTRACT FROM AUTHOR]

A manganese ion and a ditopic pentadentate ligand were used to self-assemble either an [S.sub.8] symmetrical 48-membered hexadecanuclear or an [S.sub.10] symmetrical 60-memebred icosanuclear manganese metallamacrocycle. The icosanuclear manganese metallamacrocycle was observed to have a remarkable toroidlike shape with a relatively large internal hydrophobic cavity and hence could be considered as a new donut-shaped host to accommodate small organic molecules.

The preparation of discrete metal-organic polyhedra (MOP) with nanosized cavities by combining triangular C3-symmetric facial ligands and a potential hexatopic Cu(II) ion is discussed. Findings reveal that the nitrate anion results in 2-fold interpenetrating MOFs with an augmented primitive 3-D cubic network topology.

The construction of a new chiral pentadecanuclear metallamacrocycle using a pentadentate bridging ligand is described. The cyclic system is found to exhibit a sextuple twisted Mobius topology.

A study reports the synthesis of a new [S.sub.4]-symmetric icosanuclear manganese metalladiazamacrocycle using a pentadentate ligand, N-3-phenyl-trans-2-propenoylsalicylhydrazide ([H.sub.3]L), that has a rigid and bulky terminal N-acyl group. It is found that a 20 cyclic repeat of an -(Mn-N-N)-linkage results in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle.

Suitable designed C3-symmetric facial ligands and C4-symmetric metal ions are used as a general strategy for the preparation of face-driven corner-linked truncated octahedral nanocages. The cavity size and the port size of the cage can be controlled depending on the size of the facial ligands, which offers possibilities of developing suitable nanosized host systems that can accommodate suitable small molecular guests or chiral catalysts.

A Pd6L8 type coordination driven self-assembly was constructed using a tripodal ligand L (L = N1,N3,N5-trimethyl-N1,N3,N5-tris[(pyridin-4-yl)methyl]-1,3,5-benzene tricarboxamide) and palladium nitrate. The self-assembly was fully characterised using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance spectroscopy, electrospray ionization-mass spectroscopy, thermogravimetric analysis, energy-dispersive X-ray spectroscopy and elemental analysis. Use of high resolution transmission electron microscopy (HR-TEM) analysis confirms the discrete nature of the assembly with a dimension of ∼2.8 nm, consistent with the density functional theory optimised structure. The assembly acts as an efficient homogeneous catalyst for a copper and phosphine free Sonogashira reaction under mild and aerobic conditions in aqueous medium. The catalyst shows equal efficiency for both electron deficient and electron rich aryl iodides and bromides and is also suitable for use with aliphatic alkynes. The utility of the catalyst as a reusable heterogeneous catalyst in toluene was assessed up to the 3rd cycle without any significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]