Related Experiment Video
Updated: May 28, 2025
Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Crystal structures of zinc(II) coordination complexes with iso-quinoline N-oxide
Erin N Groneck1, Nathan Peek1, Will E Lynch1
1Department of Biochemistry Chemistry and Physics Georgia Southern University, Armstrong Campus 11935 Abercorn Street Savannah GA 31419 USA.
Abstract:
The reaction of one equivalent of zinc(II) halide salts with two equivalents of iso-quinoline N-oxide (iQNO; C9H7NO) in methanol yields compounds of the general formula [ZnX 2(iQNO)2], with X = Cl- (I), Br- (II) and I- (III). However, starting with zinc(II) perchlorate or nitrate leads to the formation of complex ions with the compositions [Zn(iQNO)6](X)2 for X = ClO4 - (IV), and [Zn(iQNO)(H2O)5](iQNO)2 X 2 for X = NO3 - (V). Complexes (I), (II) and (III), namely di-chlorido-bis-(iso-quinoline N-oxide-κO)zinc(II) [ZnCl2(C9H7NO)2], di-bromido-bis-(iso-quinoline N-oxide-κO)zinc(II) [ZnBr2(C9H7NO)2], and di-iodido-bis-(iso-quinoline N-oxide-κO)zinc(II) [ZnI2(C9H7NO)2], each exhibit a distorted tetra-hedral coordination geometry around the zinc(II) ion coordinated by two iQNO ligands bound through the oxygen atom and two halide ions. The zinc ion lies on a crystallographic twofold axis in the bromo complex. The X-Zn-X bond angles are approximately 15-17° larger than the O-Zn-O bond angles resulting in the observed tetra-hedral distortion. In complex (IV), hexa-kis-(iso-quinoline N-oxide-κO)zinc(II) bis-(perchlorate), [Zn(C9H7NO)6](ClO4)2, the zinc(II) ion occupies a special position with 3 site symmetry and is octa-hedrally coordinated by six iQNO ligands, albeit with slight distortions evidenced by a spread of cis bond angles from 85.82 (4) to 94.18 (4)°. The chlorine atom of the perchlorate anion lies on a crystallographic threefold axis. Finally, complex (V) crystallizes with a pseudo-octa-hedral geometry; penta-aqua-(iso-quinoline N-oxide-κO)zinc(II) dinitrate-iso-quinoline N-oxide (1/2), [Zn(C9H7NO)(H2O)5](NO3)2·2(C9H7NO). The nitrate ions and non-coordin-ated iQNO mol-ecules engage in π-stacking and hydrogen-bonding inter-actions with the coordinated water mol-ecules. The iQNO-Zn-O equatorial bond angles range from 88.98 (9) to 94.90 (9)°, with the largest deviation from a perfect octa-hedral angle attributed to the influence of a weak C-H⋯O (from water) inter-action (2.287 Å) involving the bound iQNO ligand.
More Related Videos
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
16:11Thermochemical Studies of NiII and ZnII Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Related Concept Videos
02:57Coordination Number and Geometry
02:42Ionic 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...
02:34Structural 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...
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:46Crystal 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,...
02:42Valence Bond Theory