A one-dimensional bromide-bridged PtII/PtIV mixed-valence complex with a 2-bromoethanesulfonate counter-ion

The title salt, catena-poly[[[bis(ethylenediamine)platinum(II)]-μ-bromido-[bis(ethylenediamine)platinum(IV)]-μ-bromido] tetrakis(2-bromoethanesulfonate) dihydrate], {[PtIIPtIVBr2(C2H8N2)4](C2H4BrSO3)4·2H2O} n , crystallizes in the space group P21212. It has a linear chain structure extending parallel to the c axis, composed of square-planar [Pt(en)2]2+ and elongated octahedral trans-[PtBr2(en)2]2+ cations (en is ethylenediamine) stacked alternately and bridged by the Br atoms. The Pt site of the [PtII/IV(en)2] unit is located on a general position. The Br site, which is also located on a general position, is equally disordered over two positions. The Pt and Br atoms form a slight zigzag ...Br—PtIV—Br...PtII... chain, with PtIV—Br bond lengths of 2.453 (2) and 2.491 (3) Å, PtII...Br contacts of 3.069 (2) and 3.032 (3) Å, and PtIV—Br...PtII angles of 178.06 (13) and 177.70 (13)°. The mixed-valence state of the Pt site is expressed by the parameter δ = (PtIV–Br)/(PtII...Br), with values of 0.799 and 0.822 for the two independent Br atoms. In the crystal, N—H...O and O—H...O hydrogen bonds between the amine groups of the Pt complex chains, the sulfonate groups and water molecules of crystallization, stabilize the cationic columnar structure.

Divalent metal ions modulated strong frustrated M(ii)–Fe(iii)3O (M = Fe, Mn, Mg) chains with metamagnetism only in a mixed valence iron complex

Using divalent ions to link the frustrated Fe(iii)3O units two isostructural chains were generated with distinct magnetic behaviour: frustrations and metamagnetism in mixed valence complex, but magnetic frustrations in heterometallic complexes.

A mixed-valence complex of cobalt based on 3-methoxysalicylaldoxime

A new tetranuclear mixed-valence cobalt complex, namely di-μ2-azido-diazidodiethanolbis{μ2-2-[(hydroxyimino)methyl]-6-methoxyphenolato}bis{μ3-6-methoxy-2-[(oxidoimino)methyl]phenolato}dicobalt(II)dicobalt(III) ethanol disolvate, [CoII2CoIII2(C8H7NO3)2(C8H8NO3)2(N3)4(C2H5OH)2]·2C2H5OH, has been synthesized by the reaction of Co(OAc)2·4H2O (OAc is acetate) with 3-methoxysalicylaldoxime (H2mosao) in an ethanol solution. In the complex, the four Co cations all display distorted octahedral coordination environments and they are bridged by two κ2,κ1,κ1;μ3-mosao2−ligands, two κ2,κ2;μ2-Hmosao−ligands and two μ2-N3−anions to form a tetranuclear [Co4N4O4] cluster. Adjacent clusters are connected through weak C—H...N and C—H...O interactions, resulting in a two-dimensional supramolecular network parallel to theacplane. The magnetic properties of the complex have also been studied.