Synthesis, Crystal Structure and DFT Studies of a New Dinuclear Ag(I)-Malonamide Complex.

Saied Soliman,Assem Barakat,Mohammad Islam,Hazem Ghabbour

doi:10.3390/molecules23040888

Abstract

The synthesis and structural aspects of a new dinuclear silver (I) complex with malonamide type ligand (L) is reported. Each Ag ion in the [Ag2L2(NO3)2]·H2O complex is coordinated to two ligands, L, each acting as a bridged ligand via its two pyridine arms; Ag(I) acts as a connector between them. Two types of Ag-ligands close contacts were detected: Ag–N1, Ag–N4 from the two L units, and Ag–O5, Ag—O6 from the two nitrate anions, wherein both the nitrate ions are inside the cage formed by the [Ag2L2] unit. The coordination geometry around each Ag(I) is a distorted tetrahedron. The [Ag2L2(NO3)2] complex units are connected by weak intermolecular C—H…O interactions. The different intermolecular interactions were quantified using Hirshfeld surface analysis. Using two DFT methods (B3LYP and WB97XD), the nature and strength of the Ag–N and Ag–O interactions were described using atoms in molecules (AIM) and natural bond orbital (NBO) analyses. Topological parameters indicated that the strength of the two Ag–N bonds was similar, while that of the two Ag–O interactions were significantly different. Moreover, the Ag–N interactions have a predominant covalent character, while the Ag–O interactions are mainly ionic. The NBO analysis indicated that the most important anti-bonding Ag-orbital in these interactions has an s-orbital character.

Highlights

N,N-Malonamide derivatives (MAD) are important scaffolds present in many pharmaceuticals, synthetic and natural products
The interaction energies at the BCPs were estimated using the relationship, Eint = V(r)/2 [34]. These results indicated that the nitrate anion acts as a bridged ligand connecting the two silver atoms, with one weak and one strong Ag–O interaction
The chemical structure of the synthesized complex, deduced by a single crystal X-ray diffraction technique, shows that the silver (I) ion is bound to two N and two O atoms

Summary

Introduction

N,N-Malonamide derivatives (MAD) are important scaffolds present in many pharmaceuticals, synthetic and natural products. MAD have possessed several of the biological targets including selective and effective targeting to the γ optical receptor [1] and has been proved to be effective in treating Alzheimer’s disease [2] and cancer [3] These compounds were identified as potent inhibitors of the α-glucosidase enzyme [4,5]. They find notable applications in peptidomimetic compound synthesis [6,7,8]. These compounds have the ability to bind with alkali, alkaline earth and transition metals, representing excellent ionophores for the construction of alkaline earth and alkali cation-selective electrodes [9]. Malonamide motifs have been used for the “green” extraction of some heavy metals [10]

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