Snapshot and crystallographic observations of kinetic and thermodynamic products for NO<sub>2</sub>S<sub>2</sub> macrocyclic complexes.
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Abstract | :
Direct observation and structural characterization of a kinetic product and a thermodynamic product for complexes with an NO2S2 macrocycle (L) are reported. L reacts with copper(I) iodide to give a mononuclear complex [Cu(L)]2(Cu2I4)·2CH2Cl2 (1), featuring three separate units. When cadmium(II) iodide was reacted with L, an anion-coordinated complex [Cd(L)I]2(Cd2I6)·4CH3CN (2) with a needle-type crystal shape was formed as the kinetic product. Interestingly, when the needle-type kinetic product was left undisturbed in the mother solution it gradually transformed to the pseudo-dimer complex [Cd2(L)2I2](Cd2I6) (3) with a brick-type crystal shape as the thermodynamic product. The dissolution-recrystallization process resulted in the elimination of the lattice solvent molecules (aceto-nitrile) in 2 and the contraction of two neighboring macrocyclic complex units [Cd(L)I]+, forming the pseudo-dimer 3via an intermolecular Cd⋯I interaction between two monomers. For the entire process from kinetic to thermodynamic products, it was possible to obtain sequential photographic snapshots, single-crystal X-ray structures and powder X-ray diffraction patterns. For the copper(I) and cadmium(II) complexes, competitive NMR results agree with the solid-state data that show copper(I) has a higher affinity for L than does cadmium(II). |
Year of Publication | :
2018
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Journal | :
IUCrJ
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Volume | :
5
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Issue | :
Pt 1
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Number of Pages | :
45-53
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Date Published | :
2018
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URL | :
http://scripts.iucr.org/cgi-bin/paper?yc5012
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DOI | :
10.1107/S2052252517015081
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Short Title | :
IUCrJ
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