Related Experiment Video
Updated: Jul 10, 2026
Thermochemical Studies of Ni(II) and Zn(II) Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
Structural, spectroscopic, and electrochemical properties of a series of high-spin thiolatonickel(II) complexes
Jaeheung Cho1, Glenn P A Yap, Charles G Riordan
1Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
Abstract:
A series of high-spin thiolatonickel(II) complexes, [PhTttBu]Ni(SR) (PhTttBu = phenyltris((tert-butylthio)methyl)borate; 2, R = triphenylmethyl; 3, R = pentafluorophenyl; 4, R = phenyl), were synthesized via the reaction of [PhTttBu]Ni(NO3) (1) with thiols (RSH) in the presence of triethylamine. The [PhTttBu]Ni(SR) products were isolated and characterized by various physicochemical measurements including X-ray diffraction analyses. These thiolatonickel(II) complexes have a distorted trigonal pyramidal geometry with somewhat different tau values: 0.80 and 0.90 for two crystalline phases of 2, 0.74 for 3, and 0.69 for 4, where tau is a normalized measure of pyramidalization (tau = 0 for tetrahedron, tau = 1 for trigonal pyramid). The electronic absorption spectra display characteristic sulfur-to-nickel(II) charge transfer (CT) bands at 532 nm (7500 M(-1) cm(-1)) for 2, 510 nm (4800 M(-1) cm(-1)) for 3, and 569 nm (4100 M(-1) cm(-1)) for 4. The cyclic voltammograms show a quasi-reversible redox couple at E1/2 = -1.11 V for 2, and reversible redox couples at E1/2 = -1.03 V for 3 and E1/2 = -1.17 V for 4 (vs Fc+/Fc). Correlation between the tau value and the CT intensity was observed: the strong CT intensity results from the high tau value, which provides for strong orbital overlap (2 > 3 > 4). Additionally, the CT transition energy correlates with the reduction potential: both the CT transition energy and potential decrease in the order 3 > 2 > 4, consistent with the influence of decreasing electron withdrawing abilities, R = pentafluorophenyl > triphenylmethyl > phenyl. The three thiolatonickel complexes exhibit dramatically different thermal stabilities. Complex 4 is the least stable, undergoing decomposition to [kappa2-PhBttBuSPh]Ni(eta2-CH2SBut) (5) via net exchange of Ni-SPh and B-CH2SBut groups.
Related Concept Videos
02:42Valence Bond Theory
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 eye.
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,...
02:58Properties of Transition Metals
02:58Crystal 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...
02:17Structure and Nomenclature of Thiols and Sulfides