1 research outputs found
A Systematic Evaluation of the Interplay of Weak and Strong Supramolecular Interactions in a Series of Co(II) and Zn(II) Complexes Tuned by Ligand Modification
A systematic investigation on a designed series of 21
transition
metal complexes has been carried out with the intention to explore
and assess the relative strength and the way in which intermolecular
interactions, namely, weak and strong hydrogen-bonding and π–π
interactions, cooperate and direct molecular association during crystallization.
The complexes were prepared using the general M<sup>II</sup>/X<sup>–</sup>/L or HL′ (M<sup>II</sup> = Co<sup>II</sup>,
Zn<sup>II</sup>; X<sup>–</sup> = Cl<sup>–</sup>, Br<sup>–</sup>, I<sup>–</sup>, NO<sub>3</sub><sup>–</sup>, NO<sub>2</sub><sup>–</sup>, ClO<sub>4</sub><sup>–</sup>; L = 1-methyl-4,5-diphenylimidazole; and HL′ = 4,5-diphenylimidazole)
reaction system and were characterized by single-crystal X-ray crystallography.
Although the two ligands are structurally similar, the crystal packing
organization of their complexes is markedly different. In structures
with L, the 3D assembly is based only on weak C–H···X,
C–H···π, and intramolecular π···π
stacking interactions, whereas in those with HL′, it is the
recurring N–H···X motifs that clearly dominate
and guide the molecular self-assembly. The formation of such synthons
has been activated by choosing appropriate anions X, acting as terminal
ligands or counterions. In parallel, the conformational flexibility
of the two ligands serves a dual purpose: (i) L contributes to the
stabilization of complexes via intramolecular π···π
stacking interactions, and (ii) HL′ facilitates the synthon
formation by adopting appropriate conformations, even at the expenses
of the stabilizing intramolecular π···π
stacking