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Thiolate adducts of dirhodium(II) tetraacetate have proven difficult to prepare. We isolated a stable, paramagnetic Ni4Rh2 adduct containing Ni-based metallothiolates bound in axial positions of the Rh24+ core. The adduct formation is accompanied by a change of the magnetic exchange interaction in the dinuclear Ni2 subunits.

Thiolate adducts of dirhodium(II) tetraacetate have proven difficult to prepare. We isolated a stable, paramagnetic Ni

The ability of macrocyclic Co and Ni aminothiolate complexes to act as metalloligands towards cuprate ions was established. Adduct formation is enabled by a thiolate-to-Cu+ charge transfer (CT) interaction giving stable heterotrimetallics with magnetic properties.

Manganese(III)-salen complexes have been reported as superoxide dismutase mimics (mSOD) that can scavenge superoxide anion radicals. They are mononuclear complexes with a variety of salen ligands. Here, two new multinuclear manganese(III)-salen complexes with 4,4′-bipyridine (4,4′-bpy) as bridging ligand and ClO4− as axial ligand or PF6− as counter anion, respectively, are reported. The dimeric complex [{Mn(ClO4)(salen)}2(μ-4,4′-bpy)] (1) was obtained from [MnCl(salen)]·2H2O and 4,4′-bipyridine which followed by addition of NaClO4. While the polymeric complex {[Mn(salen)(4,4′-bpy)]PF6}n (2) was prepared by the same procedure of 1, followed by addition of KPF6 replacing NaClO4. Compounds 1 and 2 were characterized by elemental analysis, conductometry, infrared spectroscopy, electrospray-ionization mass spectrometry, and room temperature/variable temperature magnetic susceptibility measurements. The crystal structures of compounds 1 and 2 were determined by single crystal X-ray crystallography. Furthermore, in indirect SOD tests using riboflavin photoreduction, the polymeric compound 2 shows the slightly higher SOD activity with an IC50 of 1.6 ± 0.2 µM than the dimeric compounds 1 with an IC50 of 2.0 ± 0.3 µM.

The ability of the dinickel complex [Ni2L]2+ supported by the binucleating hexaaza-dithiophenolate macrocycle (L)2− to bind linear (OCN−, SCN−) and bent triatomic anions (NO2−) has been examined. The complexes [NiII2L(μ1,1-NCO)]BPh4 (3) and [NiII2L(μ1,1-NCS)]BPh4 (4) have been synthesized by addition of KOCN or KSCN to [NiII2L](ClO4)2 (1) and characterized by IR, ESI-MS, UV-vis, SQUID magnetometry, X-ray crystallography (3) and computational studies. [Ni2L][ClO4]2 (1) binds cyanate and thiocyanate ions specifically end-on via their N atoms yielding face-sharing bis(octahedral) N3Ni(μ-S2)(μ1,1-X)NiN3 core structures (X = NCO or NCS), while no reactions occur with NO2−. The X-ray structure of 3* and accompanying DFT calculations imply that the selective binding of the pseudohalide ions is governed by repulsive host–guest CH⋯(anion)π interactions. 3 and 4 exhibit an S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and cyanato (or thiocyanato) bridges, respectively, with a value for the magnetic exchange coupling constant J of 12.6 and 9.8 cm−1 (H = −2JS1S2). The affinity of 1 for cyanate determined by absorption spectrometry in MeCN/MeOH (1/1 v/v) at I = 0.01 M is ca. two orders of magnitude higher than for thiocyanate (log K11 = 3.92(1) (3), 2.16(1) (4)). The value for 3 was found to compare favorably well with the equilibrium constant derived by isothermal titration calorimetry.

The macrocyclic binuclear tetrazole, 2,2,5,5-tetramethyl-12-oxa-1,6,7,8,16,17,18,19-octaazatricyclo[13.2.1.16,9]nonadeca-7,9(19),15(18),16-tetraene (L), reacts with copper(II) chloride or copper(II) tetrafluoroborate hexahydrate to give complexes [Cu3Cl6L2] (1) or [CuL2(H2O)2](BF4)2(H2O) (2), respectively. According to single crystal X-ray analysis, both complexes were found to be coordination polymers. In the crystal structure of complex 1, there are neutral linear bibridged trinuclear units Cu3Cl6, in which the copper atoms are linked together by double chlorine bridges. Neighboring Cu3Cl6 units are bonded to each other by two bridging macrocyclic ligands L due to coordination bonds Cu–N between terminal copper atoms of Cu3Cl6 units and the tetrazole ring nitrogen atoms of ligands L to form polymeric chains. In complex 2, the copper atom is bonded to three ligands L via the tetrazole ring nitrogen atoms, and to two water molecules, with formation of a square-pyramidal coordination of the metal. In this ...