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The asymmetric unit of the title compound, [Cr(C2O4)(C10H24N4)]2[Cr2O7]·-8H2O (C10H24N4 = 1,4,8,11-tetraazacyclotetradecane, cyclam; C2O4 = oxalate, ox) contains one [Cr(ox)(cyclam)]+ cation, one half of a dichromate anion that lies about an inversion centre so that the bridging O atom is equally disordered over two positions, and four water molecules. The terminal O atoms of the dichromate anion are also disordered over two positions with a refined occupancy ratio 0.586 (6):0.414 (6). The CrIII ion is coordinated by the four N atoms of the cyclam ligand and one bidentate oxalato ligand in a cis arrangement, resulting in a distorted octahedral geometry. The Cr--N(cyclam) bond lengths are in the range 2.069 (2)-2.086 (2) Å, while the average Cr--O(ox) bond length is 1.936 Å. The macrocyclic cyclam moiety adopts the cis-V conformation. The dichromate anion has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the cyclam N--H groups and water O--H groups as donors, and the O atoms of oxalate ligand, water molecules and the Cr2O72- anion as acceptors, giving rise to a three-dimensional network. [ABSTRACT FROM AUTHOR]

In the asymmetric unit of the title compound, [CrCl2(C10H24N4)][Cr(C2O4)- (C10H24N4)](ClO4)2 (C10H24N4 = 1,4,8,11-tetraazacyclotetradecane, cyclam; C2O4 = oxalate, ox), there are two independent halves of the [CrCl2(cyclam)]+ and [Cr(ox)(cyclam)]+ cations, and one perchlorate anion. In the complex cations, which are completed by application of twofold rotation symmetry, the CrIII ions are coordinated by the four N atoms of a cyclam ligand, and by two chloride ions or one oxalate bidentate ligand in a cis arrangement, displaying an overall distorted octahedral coordination environment. The Cr--N(cyclam) bond lengths are in the range of 2.075 (5) to 2.096 (4) Å while the Cr--Cl and Cr--O(ox) bond lengths are 2.3358 (14) and 1.956 (4) Å, respectively. Both cyclam moieties adopt the cis-V conformation. The slightly distorted tetrahedral ClO4- anion remains outside the coordination sphere. The supramolecular architecture includes N--H...O and N--H...Cl hydrogen bonding between cyclam NH donor groups, O atoms of the oxalate ligand or ClO4- anions and one Cl ligand as acceptors, leading to a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title complex salt, [Cr(C10H24N4)(NH3)2][ZnCl4]Cl•H2O, is comprised of four halves of the CrIII complex cations (the counterparts being generated by application of inversion symmetry), two tetrachloridozincate anions, two chloride anions and two water molecules. Each CrIII ion is coordinated by the four N atoms of the cyclam (1,4,8,11-tetraazacyclotetradecane) ligand in the equatorial plane and by two N atoms of ammine ligands in axial positions, displaying an overall distorted octahedral coordination environment. The Cr--N(cyclam) bond lengths range from 2.0501 (15) to 2.0615 (15) Å, while the Cr--(NH3) bond lengths range from 2.0976 (13) to 2.1062 (13) Å. The macrocyclic cyclam moieties adopt the trans-III conformation with six- and five-membered chelate rings in chair and gauche conformations. The [ZnCl4]2- anions have a slightly distorted tetrahedral shape. In the crystal, the Cl- anions link the complex cations, as well as the solvent water molecules, through N--H⋯Cl and O--H⋯Cl hydrogen-bonding inter-actions. The supramolecular set-up also includes N--H⋯Cl, C--H⋯Cl, N--H⋯O and O--H⋯Cl hydrogen bonding between N--H or C--H groups of cyclam, ammine N--H and water O--H donor groups, and O atoms of the water molecules, Cl- anions or Cl atoms of the [ZnCl4]2- anions as acceptors, leading to a three-dimensional network structure. [ABSTRACT FROM AUTHOR]

The structure of the title complex, [CrCl2(2,3,2-tet)]ClO4 (2,3,2-tet is 1,4,8,11-tetraazaundecane, C7H20N4), has been determined from synchrotron data. The CrIII ion is coordinated by the four N atoms of the 1,4,8,11-tetraazaundecane ligand in the equatorial plane and two chloride ions in an axial arrangement, displaying a slightly distorted octahedral coordination environment. The two H atoms of the secondary amines are grouped on the same side of the equatorial N4 plane (meso-RS conformation). The Cr-N bond lengths range from 2.069 (2) to 2.084 (2) Å, while the mean Cr-Cl bond length is 2.325 (2) Å. The crystal structure is stabilized by intermolecular hydrogen-bonding interactions between the primary and secondary amine groups of the 2,3,2-tet ligands, the Cl ligands and the O atoms of the perchlorate counter-anion, forming corrugated layers parallel to (010). [ABSTRACT FROM AUTHOR]

In the title compound, [Cr(ONO)2(cyclam)]NO2 (cyclam is 1,4,8,11-tetraazacyclotetradecane, C10H24N2), the complex cation is located on a twofold symmetry axis. The central Cr atom has a distorted octahedral coordination, involving two Cr-O bonds, with the monodentate nitrite O atoms adopting a cis configuration, and four Cr-N bonds. The mean Cr-N and Cr-O distances are 2.0895 (14) and 1.9698 (14) Å. [ABSTRACT FROM AUTHOR]

Studies the geometrical structures of chromium complexes. Evidence of two crystallographically independent chromium complex moieties; Existence of a strong hydrogen-bonding interaction between the atoms.; Conformational isomers of the chromium complex cation.