• Schilde, Uwe
• Awad, Duha Jawad
• Koch, Andreas
• Mickler, Wulfhard
• Strauch, Peter

Abstract

<jats:title>Abstract</jats:title><jats:p>A series of new heteroleptic <jats:italic>MN</jats:italic><jats:sub>2</jats:sub><jats:italic>S</jats:italic><jats:sub>2</jats:sub> transition metal complexes with <jats:italic>M</jats:italic> = Cu<jats:sup>2+</jats:sup> for EPR measurements and as diamagnetic hosts Ni<jats:sup>2+</jats:sup>, Zn<jats:sup>2+</jats:sup>, and Pd<jats:sup>2+</jats:sup> were synthesized and characterized. The ligands are <jats:italic>N</jats:italic><jats:sub>2</jats:sub> = 4, 4′‐bis(tert‐butyl)‐2, 2′‐bipyridine (<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy) and <jats:italic>S</jats:italic><jats:sub>2</jats:sub> =1, 2‐dithiooxalate, (dto), 1, 2‐dithiosquarate, (dtsq), maleonitrile‐1, 2‐dithiolate, or 1, 2‐dicyanoethene‐1, 2‐dithiolate, (mnt). The Cu<jats:sup>II</jats:sup> complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [Ni<jats:sup>II</jats:sup>(<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy)(<jats:italic>S</jats:italic><jats:sub>2</jats:sub>)] or[Pd<jats:sup>II</jats:sup>(<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy)(<jats:italic>S</jats:italic><jats:sub>2</jats:sub>)] as well as in tetrahedrally coordinated[Zn<jats:sup>II</jats:sup>(<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy)(<jats:italic>S</jats:italic><jats:sub>2</jats:sub>)] host structures to put steric stress on the coordination geometry of the central Cu<jats:italic>N</jats:italic><jats:sub>2</jats:sub><jats:italic>S</jats:italic><jats:sub>2</jats:sub> unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi‐occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [Ni<jats:sup>II</jats:sup>(<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy)(mnt)], is characterized by X‐ray structure analysis to prove the coordination geometry. The complex crystallizes in a square‐planar coordination mode in the monoclinic space group <jats:italic>P</jats:italic>2<jats:sub>1</jats:sub>/<jats:italic>a</jats:italic> with <jats:italic>Z</jats:italic> = 4 and the unit cell parameters <jats:italic>a</jats:italic> = 10.4508(10) Å, <jats:italic>b</jats:italic> = 18.266(2) Å, <jats:italic>c</jats:italic> = 12.6566(12) Å, <jats:italic>β</jats:italic> = 112.095(7)°. Oxidation and reductions potentials of one of the host complexes, [Ni(<jats:italic>t</jats:italic>Bu<jats:sub>2</jats:sub>bpy)(mnt)], were obtained by cyclovoltammetric measurements.</jats:p>

Topics

• density
• impedance spectroscopy
• copper
• density functional theory
• electron spin resonance spectroscopy
• space group