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Title
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Highly efficient, catalystfree, onepot, pseudo five component synthesis of novel pyrazolinecontaining Schiff bases, metal complexes formation and computational studies via DFT method
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Abstract
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In this study, a green and high yielding synthesis of novel pyrazoline?containing
Schiff bases via a one?pot pseudo five?component condensation reaction
under catalyst?free conditions in EtOH at room temperature is described.
Initially, the reaction of 1,1?bis(methylthio)?2?nitroethylene (BMTNE), with
NH2NH2.H2O is used for situ preparation of 1,1?dihydrazino?2?nitroethylene
(DHNE). Then, wide varieties of aldehydes are added to the mixture to afford
the desired products good to excellent yields. This synthetic route is presented
with several unique merits such as simplicity in operation and workup, readily
presented starting materials, and high functional group tolerance. Additionally,
the stoichiometric complex formation of these Schiff bases as ligand (L) with
various metal ions [Mn(OAc)2, Cu(OAc)2 and Zn(OAc)2] in general molecular
formula [ML] is examined via Job's method. Subsequently, theoretical analysis
of the product is accomplished using density functional theory (DFT) calculations.
According to the frontier molecular orbital (FMO) analysis, it is found
that the aryl group linked to the imine bond contributes as an electron donor
in the ligand–metal complex.
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