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Iron(II) High‐Spin and Low‐Spin Complexes from Pentaisopropylcyclopentadienyliron(II) Bis(trimethylsilyl)amide
Author(s) -
Groß Oliver A.,
Lauk Sergej,
Müller Carsten,
Gidt Wjatscheslaw,
Sun Yu,
Demeshko Serhiy,
Meyer Franc,
Sitzmann Helmut
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201700236
Subject(s) - chemistry , crystallography , amide , stereochemistry , diphenylphosphine , phosphine , catalysis , organic chemistry , biochemistry
Two new complexes, [(C 5 Me 5 )FeBr(tmeda)] (tmeda = tetramethylethylenediamine) and [{C 5 (CHMe 2 ) 5 }FeN(SiMe 3 ) 2 ], have been synthesized and characterized as high‐spin iron(II) complexes with typical distances between the iron atom and the center of gravity of the C 5 ring (Fe–Cp cent ) exceeding 190 pm and displaying paramagnetic behavior in solution. Both are analogues of known complexes, namely, the Jonas complex [(C 5 Me 5 )FeCl(tmeda)] and the Siemeling “ pogo‐stick” complex [(C 5 Me 5 )FeN(SiMe 3 ) 2 ]. The silylamide [{C 5 (CHMe 2 ) 5 }FeN(SiMe 3 ) 2 ] was treated with water to yield the bridged hydroxo dimer [{C 5 (CHMe 2 ) 5 }Fe(µ‐OH)] 2 with high‐spin iron(II) configuration. With 2,5‐dimethylpyrrole the azaferrocene derivative [{C 5 (CHMe 2 ) 5 }Fe(NC 4 H 2 Me 2 ‐2,5)] was obtained, and with diphenylphosphine a few crystals of the diphosphine hydride [{C 5 (CHMe 2 ) 5 }FeH(HPPh 2 ) 2 ] as well as a sample of its dehydrogenative P–P coupling product [{C 5 (CHMe 2 ) 5 }FeH(Ph 2 P–PPh 2 )] n ( n = 1 or 2) have been obtained, which are both diamagnetic 18‐valence‐electron complexes. Two‐coordinated [{C 5 (CHMe 2 ) 5 }FeN(SiMe 3 ) 2 ] features sizeable negative magnetic anisotropy and slow magnetic relaxation with an effective energy barrier for spin reversal of 113 cm –1 under an applied field of 3000 Oe.