Cyanido‐Bearing Cobalt(II/III) Metalloligands – Synthesis, Crystal Structure, and Magnetic Properties1. Issue 27 (9th May 2014)

• Record Type: Journal Article
• Authors: Alexandru, Maria‐Gabriela; Visinescu, Diana; Marino, Nadia; De Munno, Giovanni; Vallejo, Julia; Lloret, Francesc; Julve, Miguel
• Other Names: Crans Debbie C. sponsoringEditor.; Nordlander Ebbe sponsoringEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 27(2014)
• Page Start: 4564
• Page End: 4572
• Publication Date: 2014-05-09
• Subjects: Low‐spin complexes -- Metalloligands -- Cyanides -- Cobalt -- Magnetic properties; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201402190
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: New examples of cyanido‐bearing cobalt(III/II) complexes have been obtained by treatment of CoCl2 · 6H2 O with bidentate nitrogen donors and potassium cyanide in a methanol/water mixture. Depending on the chelating ligand, the cobalt(III) complexes PPh4 [Co(en)(CN)4 ] (1, en = ethylenediamine), PPh4 [Co(ampy)(CN)4 ]· 1.5H2 O [2, ampy = 2‐(aminomethyl)pyridine], and PPh4 [Co(phen)(CN)4 ]· CH3 OH· 0.25H2 O (3, phen = 1, 10‐phenanthroline) and the cobalt(II) complex PPh4 [Co(dmphen)(CN)3 ]· 3H2 O (4, dmphen = 2, 9‐dimethyl‐1, 10‐phenanthroline) were obtained. The complexes were characterized by single‐crystal X‐ray diffraction and variable‐temperature magnetic measurements. They are all mononuclear species with six‐coordinate cobalt(III) (1 –3 ) and five‐coordinate cobalt(II) centers (4 ), and two nitrogen atoms from each bidentate ligand (1 –4 ) and four (1 –3 ) or three cyanide carbon atoms (4 ) build somewhat distorted octahedral (1 –3 ) or square‐pyramidal (4 ) surroundings. Complexes1 –3 are diamagnetic cobalt(III) compounds, whereas4 is a low‐spin cobalt(II) complex that exhibits Curie behavior in the temperature range 10–300 K. The g values of the X‐band electron paramagnetic resonance (EPR) spectrum of4 both in the solid state and in dichloromethane solution at 4.0 K ( g ⟂ = 2.28 > g ∥ = 2.0) reveal that its unpaired electron is defined by a d z 2 ‐type orbital. Complexes1 –4 can be viewed as new metalloligands for metal assemblies. Abstract : Three diamagnetic Co III complexes PPh4 [Co(L)(CN)4 ] [L = ethylenediamine (en), 1 ; 2‐(aminomethyl)pyridine (ampy), 2 ; 1, 10‐phenanthroline (phen), 3 ] and one Co II complex PPh4 [Co(dmphen)(CN)3 ] (4, dmphen = 2, 9‐dimethyl‐1, 10‐phenanthroline) were obtained and characterized by single‐crystal XRD and FTIR spectroscopy. Complex4 forms weakly antiferromagnetically coupled Co II ··· Co II supramolecular dimers.