Crystal structure and conformational analysis of s-cis-(acetylacetonato)(ethylenediamine-N,N′-diacetato)-chromium(III)

Crystal structure of hexa-kis-(urea-κO)chromium(III) dichromate bromide monohydrate from synchrotron X-ray data

The title bromide salt, [Cr{CO(NH2)2}6](Cr2O7)Br·H2O, is isotypic to the corresponding chloride salt. Within the complex cation, the Cr(III) atom is coordinated by six O atoms of six urea ligands, displaying a slightly distorted octa-hedral coordination environment. The Cr-O bond lengths involving the urea ligands are in the range 1.9534 (13)-1.9776 (12) Å. The Cr2O7 (2-) anion has a nearly staggered conformation, with a bridging angle of 130.26 (10)°. The individual components are arranged in rows extending parallel to [100]. The Br(-) anion links the complex cation, as well as the solvent water mol-ecule, through N-H⋯Br and O-H⋯Br hydrogen-bonding inter-actions. The supra-molecular architecture also includes N-H⋯O and O-H⋯O hydrogen bonding between urea N-H and water O-H donor groups and the O atoms of the Cr2O7 (2-) anion as acceptor atoms, leading to a three-dimensional network structure.

Synthesis, conformational structure and spectroscopic properties of trans-diazidobis(2,2-dimethyl-1,3-propanediamine)chromium(III) perchlorate

A new complex trans-anti-[Cr(Me2tn)2(N3)2]ClO4·2H2O, where Me2tn=2,2-dimethyl-1,3-propanediamine was synthesized and characterized, and its molecular structure was established by single-crystal X-ray diffraction at 95K. The complex crystallized in the space group C2/c of the monoclinic system with four mononuclear formula units in a cell of dimensions a=16.600 (3), b=7.709 (2), c=16.865 (3)Å, and β=99.07 (3)°. The chromium(III) atom was in a distorted octahedral coordination with four N atoms of two chelating Me2tn ligands and two N atoms of the azido group in the trans axial position. The two six-membered rings in the complex adopted only anti chair-chair conformations with respect to each other The important bond lengths are CrN(azide) 2.007 (2), CrN(Me2tn) 2.081 (2), 2.082 (2), NN(azide) 1.184 (2) and 1.156 (2)Å, respectively. The crystal lattice is stabilized by hydrogen bonding interactions among the ClO4(-), hydrate molecule, N3(-), and NH groups of the Me2tn ligand. The ligand field analysis as well as the IR and electronic spectral properties were described.