Related Experiment Video
Updated: Feb 5, 2026

Crystallizing Membrane Proteins for Structure Determination using Lipidic Mesophases
Published on: November 21, 2010
Crystal structure of tetra-kis-(μ
Ugochukwu Okeke1, Raymond Otchere1, Yilma Gultneh1
1Department of Chemistry, Howard University, 525 College Street NW, Washington, DC 20059, USA.
Abstract:
The title compound, [Zn3(C14H11Br2N2O)4](ClO4)2·2CH3CN, crystallizes as a symmetrical trinuclear cation with all three metal atoms being located on a twofold rotation axis. It contains a tetra-hedral ZnII atom that bridges two six-coordinate ZnII atoms. The complex contains N- and O-donor atoms of four tridentate 2,4-di-bromo-6-{[2-(pyridin-2-yl)eth-yl]imino-meth-yl}phenolate ligands. The ratio of ZnII atoms to ligands is 3:4. The two terminal ZnII cations adopt distorted octa-hedral geometries and the central ZnII cation adopts a distorted tetra-hedral geometry. In the cation there are π-π inter-actions between the di-bromo-phenyl rings, as well as halogen-bonding inter-actions between the di-bromo-phenyl rings in the cation, which stabilize its conformation. In addition, there are C-H⋯O inter-actions between the anions and both the cations and solvent mol-ecules as well as C-H⋯N inter-actions between the cation and solvent mol-ecules. These inter-species inter-actions link the cations, anions and solvent mol-ecules into a complex three-dimensional array.
Related Concept Videos
Ionic Crystal Structures
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
Crystal Growth: Principles of Crystallization
Initiating crystallization involves manipulating the concentration of the solute and the temperature of the solution. Since crystal growth occurs when the ratio of concentration and solubility of the solute in the solvent...
Structures of Solids
Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...

