Experimental observation of spin delocalisation onto the aryl-alkynyl ligand in the complexes [Mo(C=CAr)(Ph2PCH2CH2PPh2)(?-C7H7)]+ (Ar = C6H5, C6H4-4-F; C7H7 = cycloheptatrienyl): an EPR and ENDOR investigation.
Experimental observation of spin delocalisation onto the aryl-alkynyl ligand in the complexes [Mo(C=CAr)(Ph2PCH2CH2PPh2)(?-C7H7)]+ (Ar = C6H5, C6H4-4-F; C7H7 = cycloheptatrienyl): an EPR and ENDOR investigation.
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配合物 [Mo(C=CAr)(Ph2PCH2CH2PPh2)(?-C7H7)] (Ar = C6H5, C6H4-4-F; C7H7 = 环庚三烯基) 中自旋离域的实验观察：EPR 和 ENDOR
DOI：
10.1039/c0dt00642d
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
Carter E
中科院分区：
文献类型：
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作者：
Carter E
顺磁性芳基炔配合物[Mo（C_（10）C_（10））（dppe）（η-C（7）H（7））]（+）（dppe= Ph（2）PCH（2）CH（2）PPh（2）; Ar= C（6）H（5），[1]（+）; C（6）D（5），[2]（+）; C（6）H（4）-4-F，[3]（+）; C（6）H（4）-4-Me，[5]（+））和[Mo（C_（10）CBu（t））（dppe）（η-C（7）H（7））]（+）[4]（+）的EPR和ENDOR研究表明，[Mo（C_（10）CBu（t））（dppe）（η-C（7）H（7））]（+）[4]（+）是一个稳定的配位体.直接的实验证据的离域的未成对的自旋密度超过框架的芳基-炔基配体已经获得。4-氟代衍生物[3]（+）的X波段溶液EPR光谱显示，除了C（7）H（7）环的（95/97）Mo、（31）P和（1）H的耦合外，还存在与芳基远端对位的分辨超精细耦合[a（iso）（（19）F）= 4.5 MHz，（1.6 G）]。（1）H ENDOR谱的全面分析受到系统的低g各向异性的限制，这妨碍了取向选择的使用。然而，[1]（+），[2]（+），[4]（+）和[5]（+）的（1）H cw-ENDOR冷冻溶液光谱的相互比较，结合由DFT研究得出的计算值提供的光谱模拟，有助于估计[1]（+）的实验a（iso）（1）H）超精细耦合，包括邻位，±3.7 MHz（±1.3 G）和帕拉，芳基-炔基配体的C（6）H（5）取代基的±3.9 MHz（±1.4 G）位置。
The paramagnetic aryl-alkynyl complexes [Mo (C≡ CAr)(dppe)(η-C (7) H (7))](+)(dppe= Ph (2) PCH (2) CH (2) PPh (2); Ar= C (6) H (5),[1](+); C (6) D (5),[2](+); C (6) H (4)-4-F,[3](+); C (6) H (4)-4-Me,[5](+)) and [Mo (C≡ CBu (t))(dppe)(η-C (7) H (7))](+)[4](+), have been investigated in a combined EPR and ENDOR study. Direct experimental evidence for the delocalisation of unpaired spin density over the framework of an aryl-alkynyl ligand has been obtained. The X-band solution EPR spectrum of the 4-fluoro derivative,[3](+), exhibits resolved hyperfine coupling to the remote para position of the aryl group [a (iso)((19) F)= 4.5 MHz,(1.6 G)] in addition to couplings attributable to (95/97) Mo,(31) P and (1) H of the C (7) H (7) ring. A full analysis of the (1) H ENDOR spectra is restricted by the low g anisotropy of the system which prevents the use of orientation selection. However, inter-comparison of the (1) H cw-ENDOR frozen solution spectra of [1](+),[2](+),[4](+) and [5](+), combined with spectral simulation informed by calculated values derived from DFT investigations, has facilitated estimation of the experimental a (iso)((1) H) hyperfine couplings of [1](+) including the ortho,±3.7 MHz (±1.3 G) and para,±3.9 MHz (±1.4 G) positions of the C (6) H (5) substituent of the aryl-alkynyl ligand.