عنوان مجله
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INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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چکیده
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In this work, we report solvent-induced complexation properties of a newN2S2 tetradentate
bis-thiosemicarbazone ligand (H2LI), prepared by the condensation of 4-phenylthiosemicarbazide
with bis-aldehyde, namely 2,2’-(ethane-1,2-diylbis(oxy)dibenzaldehyde, towards nickel(II). Using
ethanol as a reaction medium allowed the isolation of a discrete mononuclear homoleptic complex
[NiLI] (1), for which its crystal structure contains three independent molecules, namely 1-I, 1-II, and 1-
III, in the asymmetric unit. The doubly deprotonated ligand LI in the structure of 1 is coordinated in
a cis-manner through the azomethine nitrogen atoms and the thiocarbonyl sulfur atoms. The coordination
geometry around metal centers in all the three crystallographically independent molecules of
1 is best described as the seesaw structure. Interestingly, using methanol as a reaction medium in the
same synthesis allowed for the isolation of a discrete mononuclear homoleptic complex [Ni(LII)2] (2),
where LII is a monodeprotonated ligand 2-(2-(2-(2-(dimethoxymethyl)phenoxy)ethoxy)benzylidene)-
N-phenylhydrazine-1-carbothioamide (HLII). The ligand LII was formed in situ from the reaction of
LI with methanol upon coordination to the metal center under synthetic conditions. In the structure
of 2, two ligands LII are coordinated in a trans-manner through the azomethine nitrogen atom and
the thiocarbonyl sulfur atom, also yielding a seesaw coordination geometry around the metal center.
The charge and energy decomposition scheme ETS-NOCV allows for the conclusion that both structures
are stabilized by a bunch of London dispersion-driven intermolecular interactions, including
predominantly N–HS and N–HO hydrogen bonds in 1 and 2, respectively; they are further
augmented by less typical C–HX (where X = S, N, O, ), CHHC, stacking and the most
striking, attractive long-range intermolecular C–HNi preagostic interactions. The latter are found
to be determined by both stabilizing Co
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