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应用密度泛函DFT理论PBE0方法对单核配合物[Fe(CO)3(MePhPpy)2]1、双核配合物[Fe(CO)3(MePhPpy)2(MCl2)](2∶M=Zn,3∶M=Cd,4∶M=Hg)和[Fe(CO)3(MePhPpy)2(HgCl2)2]5的结构进行了理论计算,研究了双核配合物中金属-金属间相互作用及其对31P化学位移的影响.结果表明:(1)配合物2～4的稳定性为2>4>3.(2)Fe-M相互作用的强弱顺序为2≈3<4.(3)NBO分析得到Fe-M相互作用主要表现为σFe-P→nM和σFe-C→nM的电荷转移作用,而N-M的相互作用以nN→nM离域作用为主.(4)用DFT-PBE0-GIAO方法计算1,3,5的31P化学位移值与实验值较接近,并预测了2和4的31P化学位移分别为61.66和56.49.(5)形成双核配合物后,σFe-C→σF*e-P离域增大,而σFe-P→σF*e-C减小,使得P原子核所受的屏蔽作用比1的大,故双核配合物的31P化学位移比单核配合物的小.
The mononuclear complex [Fe (CO) 3 (MePhPpy) 2] 1, dinuclear complex [Fe (CO) 3 (MePhPpy) 2 (MCl2)] was synthesized by density functional theory (DFT) The structure of [Fe (CO) 3 (MePhPpy) 2 (HgCl2) 2] 5 has been calculated theoretically. The interaction between metal and metal in the binuclear complex and its (2) The order of the strength of Fe-M interaction is 2 ≈ 3 <4. (3) The stability of 31P chemical shifts is shown in the following table: (1) The stability of complexes 2-4 is 2> 4> NBO analysis shows that the Fe-M interaction is mainly due to the charge transfer of σFe-P → nM and σFe-C → nM, while the interaction of NM is dominated by nN → nM delocalization. (4) With DFT-PBE0- GIAO calculated 1, 3, 5 31P chemical shift value and the experimental value is close to 2 and 4 predicted 31P chemical shifts were 61.66 and 56.49. (5) After the formation of binuclear complex, σFe-C → σF * eP delocalization increases, while σFe-P → σF * eC decreases, making the shielding effect of P nucleus larger than 1, so the 31P chemical shift of binuclear complex is smaller than that of mononuclear complex.