Electronic Structure and Slow Magnetic Relaxation of Low-Coordinate Cyclic Alkyl(amino) Carbene Stabilized Iron(I) Complexes

• Published in: Journal of the American Chemical Society Vol. 136; no. 34; pp. 11964 - 11971
• Main Authors: Samuel, Prinson P, Mondal, Kartik Chandra, Amin Sk, Nurul, Roesky, Herbert W, Carl, Elena, Neufeld, Roman, Stalke, Dietmar, Demeshko, Serhiy, Meyer, Franc, Ungur, Liviu, Chibotaru, Liviu F, Christian, Jonathan, Ramachandran, Vasanth, van Tol, Johan, Dalal, Naresh S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.08.2014
• Subjects: iron; magnetic fields; magnetic materials; oxidation; spectroscopy
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/ja5043116

Cyclic alkyl(amino) carbene stabilized two- and three-coordinate Fe(I) complexes, (cAAC)2FeCl (2) and [(cAAC)2Fe][B(C6F5)4] (3), respectively, were prepared and thoroughly studied by a bouquet of analytical techniques as well as theoretical calculations. Magnetic susceptibility and Mössbauer spectroscopy reveal the +1 oxidation state and S = 3/2 spin ground state of iron in both compounds. 2 and 3 show slow magnetic relaxation typical for single molecule magnets under an applied direct current magnetic field. The high-frequency EPR measurements confirm the S = 3/2 ground state with a large, positive zero-field splitting (∼20.4 cm–1) and reveal easy plane anisotropy for compound 2. CASSCF/CASPT2/RASSI-SO ab initio calculations using the MOLCAS program package support the experimental results.