Solid-State Spin Crossover of Ni(II) in a Bioinspired N3S2 Ligand Field

Autor:	Michael P. Jensen, Victor G. Young, Gordon T. Yee, Huaibo Ma, Jeffrey L. Petersen
Rok vydání:	2011
Předmět:	Models Molecular Ligand field theory Ligand Stereochemistry Solid-state chemistry.chemical_element General Chemistry Crystallography X-Ray Ligands Biochemistry Catalysis Crystallography Colloid and Surface Chemistry chemistry Nickel Spin crossover Boron
Zdroj:	Journal of the American Chemical Society. 133:5644-5647
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja110890v
Popis:	The complex Tp(Ph,Me)NiS(2)CNMe(2) [Tp(Ph,Me) = hydrotris(3-phenyl-5-methyl-1-pyrazolyl)borate] features a bioinspired N(3)S(2) ligand set supporting a five-coordinate, trigonally distorted square-pyramidal geometry in the solid state. Spin crossover of Ni(II) was demonstrated by temperature-dependent X-ray crystallography and magnetic susceptibility measurements. The crystal lattice contains two independent molecules (i.e., Ni1 and Ni2). At 293 K, the observed bond lengths and susceptibility are consistent with high-spin (S = 1) Ni(II), and both molecules exhibit relatively short axial Ni-N bonds and long Ni-N and Ni-S equatorial bonds. At 123 K, the Ni1 complex remains high-spin, but the Ni2 molecule substantially crosses to a structurally distinct diamagnetic (S = 0) state with significant elongation of the axial Ni-N bond and offsetting contraction of the equatorial bonds. The temperature-dependent susceptibility data were fit to a spin equilibrium at Ni2 [ΔH° = 1.13(2) kcal/mol and ΔS° = +7.3(1) cal mol(-1) K(-1)] consistent with weak coupling to lattice effects. Cooling below 100 K results in crossover of the Ni1 complex.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::5796d58713607f1621c7e7b23b812f35 https://doi.org/10.1021/ja110890v Zobrazit plný text záznamu