The reactions of the sulfonium salts [Fe2(CO)2(cp)2(μ-CO){μ-C(X)SMe2}]SO3CF3[X = CN (1a), H (1b)] with a variety of amines are presented. la yields ammonium cations [Fe2-(CO)2(cp)2(μ-CO){μ-C(CN)NR3}] [R = Me (2), Dabco (3) (Dabco = 1,4-diazabicyclo[2.2.2]-octane)], aminoalkylidene [Fe2(CO)2(cp)2(μ-CO){μ-C(CN)NR2}] (4), isocyanide Fe2(CO)2(cp)2(μ-CO)(μ-CNR)] (7), or diaminoalkylidene [Fe2{CN(H)(CH2)2N(H)}(CO)(cp)2(μ-CO)2]. (11) complexes by reacting with tertiary amines, secondary amines, primary amines, or ethylenediamine, respectively. 1b and secondary amines yield [Fe2(CO){C(H)NR2}(cp)2(μ-CO)2] (6). The formation of type 4 bridging and 6 terminal aminoalkylidene derivatives also via μ-C addition of CN- or H_to aminoalkylidyne [Fe2(CO)2(cp)2(μ-CO)(μ-CNR2)]+, respectively, as well as the preparation of the terminal [Fe2{C(CN)NPrijavax.xml.bind.JAXBElement@226e74d2}(CO)(cp)2(μ-CO)2] (5) from 1a and NHPri2, allows to clarify the role of electronic and steric effects in determining the position of the aminoalkylidene ligands. The X-ray structure of 5 has been determined. The crystal contains two independent molecules of the trans-isomer. The terminally bonded aminoalkylidene ligand exhibits weaker Fe-C(carbene) (Fe-C 1.915(3) Å) and stronger C(carbene)-N(amine) π bonds (C-N 1.320(4) Å) with respect to the bridging coordination. Electrochemistry shows that 5 undergoes a chemically reversible one electron oxidation to the corresponding monocation [5]+, which has been characterized by X-band EPR spectroscopy. All the complexes have been spectroscopically characterized, and a variable-temperature NMR on [Fe2(CO){C(H)NMe2}(cp)2(μ-CO)2] (6a) indicates exchange of the aminoalkylidene ligand between the two Fe atoms. © 1995, American Chemical Society. All rights reserved.
Zanotti V., Bordoni S., Busetto L., Carlucci L., Palazzi A., Serra R., et al. (1995). Diiron Aminoalkylidene Complexes. ORGANOMETALLICS, 14(11), 5232-5241 [10.1021/om00011a046].
Diiron Aminoalkylidene Complexes
Bordoni S.;Serra R.;Monari M.;
1995
Abstract
The reactions of the sulfonium salts [Fe2(CO)2(cp)2(μ-CO){μ-C(X)SMe2}]SO3CF3[X = CN (1a), H (1b)] with a variety of amines are presented. la yields ammonium cations [Fe2-(CO)2(cp)2(μ-CO){μ-C(CN)NR3}] [R = Me (2), Dabco (3) (Dabco = 1,4-diazabicyclo[2.2.2]-octane)], aminoalkylidene [Fe2(CO)2(cp)2(μ-CO){μ-C(CN)NR2}] (4), isocyanide Fe2(CO)2(cp)2(μ-CO)(μ-CNR)] (7), or diaminoalkylidene [Fe2{CN(H)(CH2)2N(H)}(CO)(cp)2(μ-CO)2]. (11) complexes by reacting with tertiary amines, secondary amines, primary amines, or ethylenediamine, respectively. 1b and secondary amines yield [Fe2(CO){C(H)NR2}(cp)2(μ-CO)2] (6). The formation of type 4 bridging and 6 terminal aminoalkylidene derivatives also via μ-C addition of CN- or H_to aminoalkylidyne [Fe2(CO)2(cp)2(μ-CO)(μ-CNR2)]+, respectively, as well as the preparation of the terminal [Fe2{C(CN)NPrijavax.xml.bind.JAXBElement@226e74d2}(CO)(cp)2(μ-CO)2] (5) from 1a and NHPri2, allows to clarify the role of electronic and steric effects in determining the position of the aminoalkylidene ligands. The X-ray structure of 5 has been determined. The crystal contains two independent molecules of the trans-isomer. The terminally bonded aminoalkylidene ligand exhibits weaker Fe-C(carbene) (Fe-C 1.915(3) Å) and stronger C(carbene)-N(amine) π bonds (C-N 1.320(4) Å) with respect to the bridging coordination. Electrochemistry shows that 5 undergoes a chemically reversible one electron oxidation to the corresponding monocation [5]+, which has been characterized by X-band EPR spectroscopy. All the complexes have been spectroscopically characterized, and a variable-temperature NMR on [Fe2(CO){C(H)NMe2}(cp)2(μ-CO)2] (6a) indicates exchange of the aminoalkylidene ligand between the two Fe atoms. © 1995, American Chemical Society. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
