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The present study accounts on the synthesis, structural characterization, self-assembled crystalline architecture, and transesterification study of a mononuclear zinc(II) complex, [Zn(H L)(H 2 O)]·(H 2 O) (1) containing a previously reported Schiff base ligand, H 3 L = N,N ′-bis(salicylidene)-1,3-diamino-2-propanol]. • Synthesis and characterization of a tetrapyramidal zinc(II)-Schiff base complex. • Zn(II) complex crystallizes in hexagonal crystal system with P 6 1 space group. • This Zn(II) complex displays good transesterification activity with initial rate constant, 1.73 × 10−4 min−1. • Computational studies agree well with the experimental results in this course of study. The article demonstrates the synthesis, structural characterization and transesterification activity of a mononuclear zinc(II) complex, [Zn(H L)(H 2 O)]·(H 2 O) (1) containing a previously reported Schiff base ligand, H 3 L = N,N ′-bis(salicylidene)-1,3-diamino-2-propanol]. X-ray structural analysis of 1 reveals that Zn(II)-Schiff base complex crystallizes in hexagonal crystal system with P 6 1 space group and adopts a distorted tetrapyramidal geometry. Self-assembled molecular units of 1 exhibit a beautiful construction of 3D crystalline architecture through intermolecular hydrogen bond wire. Zinc(II) complex displays an enhancement of fluorescence intensity in comparison to H L in methanol medium. Catalytic behaviour of 1 towards disodium salt of 2,4-dinitrophenylphosphate (PNPP) in aqueous-methanol medium exhibits good transesterification activity with initial rate constant value of 1.73 × 10−4 min−1. Detailed DFT calculations are also employed to cope with the geometrical parameters of 1 as well as to explore the proposed catalytic mechanism of transesterification activity. [ABSTRACT FROM AUTHOR]

This research work reports the synthesis, structural characterization, computational study and bio-mimicking activity of Phenoxazinone Synthase enzyme of a new phenoxido-bridged dicopper(II)-Schiff base complex, [Cu 2 (L) 3 ]ClO 4 (1), [H L (Schiff base ligand) = (Z)-2-methoxy-6-(((2-methoxyphenyl)imino)methyl)phenol]. • Synthesis and characterization of a dicopper(II)-Schiff base complex. • The dicopper(II) complex adopts different coordination geometry for each of the copper(II) centres. • This Cu(II) complex efficiently catalyzes the oxidation of 2-aminophenol to aminophenoxazinone species. • EPR study authenticates the generation of radical species in this course of catalysis. This research article reports the synthesis, structural characterization and phenoxazinone synthase activity of a new phenoxido-bridged dicopper(II)-Schiff base complex, [Cu 2 (L) 3 ]ClO 4 (1) , [H L = (Z)-2-methoxy-6-(((2-methoxyphenyl)imino) methyl)phenol]. X-ray structure of the Cu(II) complex reveals that each of the two Cu(II) centres in 1 adopts different coordination geometries (distorted octahedral and distorted square planar) and phenoxido bridges couple two Cu(II) centres to form a dinuclear copper complex with Cu⋯Cu distance 3.182 Å. The dicopper(II) complex catalyzes the aerobic oxidation of 2-aminophenol (2-AP) to aminophenoxazinone species in acetonitrile with good turnover number, 78.14 h−1. Electro-chemical and electrospray ionization mass spectrometry analysis of 1 in presence of 2-AP ensure the involvement and key role of the copper(II) centres in formation of enzyme-substrate adduct. Subsequently, electron paramagnetic resonance study confirms the generation of radical species in the course of catalysis. Finally, density functional theoretical calculations well reproduce the experimental geometrical parameters and spectroscopic behaviours of 1 and decisively argue in favour of the proposed catalytic pathways. [ABSTRACT FROM AUTHOR]

Synthesis and structural characterization of a linkage isomer, bis(2,2′-dipyridylamine)dithiocyanato(k -S)nickel(II), [Ni(dpa) 2 (k -SCN) 2 (1) of a previously reported Ni(II) complex, [Ni(dpa) 2 (k -NCS) 2 (dpa = 2,2′-dipyridylamine; SCN = thiocyanate) has been reported herein. X-ray structural analysis of 1 reveals that Ni(II) complex crystallizes in monoclinic system with P 2 1 / c space group and exists in trans configuration. The coordination geometry for 1 adopts a tetragonal structure. Supramolecular aspects of the Ni(II) complex indicate that N atom of SCN behaves as a donor and H atom of dpa ligand acts as a receptor in growing 1D crystalline structure along b axis in solid state. The aromatic rings in 1 prefer to exist in face-centred stacking with interplanar distance of 3.426 Å and supports strongly to form self-assembled 3D crystalline architecture. Hirshfeld surface analysis further recommends this crystalline assembly in solid state. 1 exhibits promising phosphatase activity towards disodium(4-nitrophenyl)phosphate (PNPP) in aqueous-methanolic medium. The hydrolytic phosphatase efficiency for 1 is determined in terms of turnover number (k cat) as 3.38 × 104 h−1. Moreover, density functional theoretical computations closely replicate the structural parameters and spectroscopic behaviour of 1. Image 1 • Synthesis and X-ray structure of a linkage isomer, bis(2,2′-dipyridylamine)dithiocyanato(k-S)nickel(II), [Ni(dpa)2(k-SCN)2]. • The nickel(II) complex efficiently cleave PNPP with TON, 3.38 × 104 h−1. • The theoretical findings employing DFT have been well corroborated with the experimental results. [ABSTRACT FROM AUTHOR]

In this work, we have developed a new one-dimensional cadmium(II) coordination polymer, [Cd(phen)(NO 3 ) 2 (H 2 O)] n ( 1 ) (phen = 1,10-phenanthroline) and structurally characterized by different spectroscopic techniques including single crystal X-ray diffraction analysis. Single crystal X-ray structural analysis of 1 indicates that Cd(II) ion in the coordination polymer crystallizes in a monoclinic system with P 2 1 space group and adopts a distorted pentagonal bipyramidal coordination geometry. This will be the first citation of a 1D Cd(II) polymer till date where nitrate ions exhibit diverse coordination motifs. Solid state emission suggests good luminescence behavior of the polymer. Spectroscopic studies reveal that the polymer is unstable in polar solvents and dominates in monomeric form. Molar conductivity and electrospray ionization mass spectral analysis in methanolic solution confirm the instability of the polymer at room temperature and authenticates the decomposition of the polymer into monomer in solution. In addition, all the structural parameters and spectroscopic behaviors have been well corroborated with the theoretical findings. [ABSTRACT FROM AUTHOR]