Evidence of chelate−chelate stacking interactions was obtained by analyzing crystal structures of square-planar transition-metal complexes from the Cambridge Structural Database. The analysis showed ...that chelate−chelate stacking interactions occur in a large number of the crystal structures of neutral square-planar complexes. We found 955 structures with 1866 chelate−chelate stacking interactions. In most of the structures, chelate rings are fused with other chelate rings or with organic aromatic rings; however, chelate−chelate stacking interactions of isolated rings were also found. In order to describe the geometry of the chelate−chelate stacking interactions, several geometric parameters were analyzed. In most of the interactions, two chelate rings are in parallel or antiparallel orientation. The normal distances are similar to the distances of stacking interactions observed in other systems, while the offset of two interacting chelate rings can be different from that observed in other systems.
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IJS, KILJ, NUK, PNG, UL, UM
Analysis of geometrical parameters in the crystal structure of square-planar complexes, with and without chelate rings, of all transition metals from Cambridge Structural Database shows that there ...are stacking interactions between the phenyl ring and the chelate ring with delocalized π-bonds. Short distances between the metal and carbon atom of the phenyl ring and parallel orientation of phenyl ring with respect to the coordination plane were found in the crystal strucutres of complexes with chelate rings. There is a correlation of the distances between the centers of chelate and phenyl rings and the metal−carbon distances showing that the chelate and phenyl rings tend to overlap. In the crystal structures, there are mutual slipped-parallel orientations of the phenyl and chelate rings. The data show that the geometry of the stacking interaction between phenyl and chelate rings is similar to the geometry of the stacking interaction of two benzene rings, indicating that chelate rings can behave similarly to organic aromatic rings.
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Stacking interactions in the crystal structures of square‐planar transition metal complexes from the Cambridge Structural Database with five‐ and six‐membered chelate rings fused with C6‐arom rings ...(arom = aromatic) were analyzed. The distribution of distances between the closest C6‐arom–C6‐arom and C6‐arom–chelate contacts shows that in a large fraction of the intermolecular interactions the C6‐arom ring of one molecule is closer to the chelate than to the C6‐arom ring of the other molecule. These results indicate a possible preference of the C6‐arom ring to form stacking contacts with the chelate rings. The preference is ubiquitous and does not depend on the metal type.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Complex compounds of NiII, CoIII, CuII with bis(phthalazine-1-hydrazone)-2,6-diacetylpyridine (Hz2DAP) ligand were synthesised. The coordination sphere of the metals is different in spite of the same ...synthetic procedure and same degree of protonation of the ligand, Hz2DAP-H. With ZnII a neutral complex Zn(Hz2DAP-2H)·H2O is obtained with double deprotonated ligand molecule. Display omitted
Four new complex compounds of bis(phthalazine-1-hydrazone)-2,6-diacetylpyridine (Hz2DAP) ligand with NiII, CoIII, CuII and ZnII metal centres were synthesised and characterised by single-crystal X-ray diffraction and IR spectral data. The antimicrobial activity of Hz2DAP and the obtained complexes Co(Hz2DAP-H)Cl2·MeOH, Ni(Hz2DAP-H)Cl·MeOH, Cu(Hz2DAP-H)Cl and Zn(Hz2DAP-2H)·H2O were tested in vitro against selected Gram(−) and Gram(+) bacterial strains and fungi. The antimicrobial activity of the ligand is negligible, while its complexes with NiII, CoIII and CuII show considerable activity against Escherichia coli, Staphylococcus aureus and Micrococcus lysodeikticus. On the contrary, Zn(Hz2DAP-2H)·H2O promotes the growth of Candida albicans, while its antibacterial activity is negligible. On the basis of thermal data and those from coupled TG/MS measurements the decomposition mechanisms were determined and evaluated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Stacking interactions in the crystal structures of square-planar transition metal complexes from the Cambridge Structural Database with five- and six-membered chelate rings fused with C
6-arom
rings ...(arom = aromatic) were analyzed. The distribution of distances between the closest C
6-arom
–C
6-arom
and C
6-arom
–chelate contacts shows that in a large fraction of the intermolecular interactions the C
6-arom
ring of one molecule is closer to the chelate than to the C
6-arom
ring of the other molecule. These results indicate a possible preference of the C
6-arom
ring to form stacking contacts with the chelate rings. The preference is ubiquitous and does not depend on the metal type.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Complexes of CdX
2 (X
=
Cl, Br, I) and ZnCl
2 with the bidentate 3
,5-dimethylpyrazole-1-carboxamidine (HL) ligand were synthesized and characterized. Single crystals were prepared from the ...corresponding metal ammine complexes and
HL·HNO
3
at a self-controlled rate. The complex formation and the thermal decomposition are explained using the HSAB principle. DFT calculations have been performed.
The complex formation of 3
,5-dimethylpyrazole-1-carboxamidinium nitrate,
HL·HNO
3
with ammine complexes of cadmium(II) halides (Cl, Br, I) and zinc(II) chloride has been investigated under self-controlled reaction conditions. The complexes have been characterized by X-ray diffraction, FT-IR spectroscopy, thermal analysis and quantum chemical calculations. In the case of cadmium bromide and iodide salts, isostructural complexes with composition of CdX
2(HL)
2 were formed. With CdCl
2 a binuclear octahedral Cd
2(HL)
4(μ-Cl)
2(NO
3)
2 complex is obtained. Zinc(II) chloride with
HL·HNO
3
gives Zn(HL)
2ClNO
3, the zinc center exhibiting severely distorted five-coordinate stereochemistry, intermediate between an ideal trigonal bipyramid and a square pyramid. The course of complex formation as well as the thermal properties of the compounds has been explained using the HSAB principle. The assignment of the FT-IR spectra was supported by DFT computations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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