XAS characterization of a Nitridoiron(IV) complex with a very short fe-n bond
XAS characterization of a Nitridoiron(IV) complex with a very short fe-n bond
复制标题
DOI：
10.1021/ic700818q
复制
发表时间：
2007-07-09
影响因子：
4.6
通讯作者：
Que, Lawrence, Jr.
中科院分区：
文献类型：
--
作者：
Rohde, Jan-Uwe;Betley, Theodore A.;Que, Lawrence, Jr.
用x射线吸收光谱法对两种[PhBP3R]Fe(N)配合物（R = iPr和CyCH2）中的新型氮化铁（IV）单元进行了表征，获得了Fe-N距离很短的直接光谱证据。1.51-1.55 A的距离反映了FeN三键的存在，这与其中一种的FeN振动一致(nu（FeN) = 1034 cm(-1)）。这种高共价键相互作用导致异常强烈的前边峰的出现，其估计面积为100（20）个单位，远远大于具有Fe- i - n -2-Fe- i， Fe- ii - nph2和Fe(III)NAd基元的相关四面体配合物，以及最近描述的六坐标(FeN)-N-V和(FeN)-N-VI配合物。两个[PhBP3R]Fe(N)配合物的Fe-IV-N距离比氧铁（IV）配合物的Fe-IV- o键长度短，这可能是由于氮基配体的pi碱度比氧配体大，而Fe(N)配合物的金属配位数较低。
X-ray absorption spectroscopy has been used to characterize the novel nitridoiron(IV) units in two [PhBP3R]Fe(N) complexes (R = iPr and CyCH2) and obtain direct spectroscopic evidence for a very short Fe-N distance. The distance of 1.51-1.55 A reflects the presence of an FeN triple bond in accord with the observed FeN vibration observed for one of these species (nu(FeN) = 1034 cm(-1)). This highly covalent bonding interaction results in the appearance of an unusually intense pre-edge peak, whose estimated area of 100(20) units is much larger than those of the related tetrahedral complexes with Fe-I-N-2-Fe-I, Fe-II-NPh2, and Fe(III)NAd motifs, and those of recently described six-coordinate (FeN)-N-V and (FeN)-N-VI complexes. The observation that the Fe-IV-N distances of two [PhBP3R]Fe(N) complexes are shorter than the Fe-IV-O bond lengths of oxoiron(IV) complexes may be rationalized on the basis of the greater pi basicity of the nitrido ligand than the oxo ligand and a lower metal coordination number for the Fe(N) complex.