To study the Cu-Cu interaction and stability of the title complexes,the structures of complexes [Cu（Ph2Ppy）（CH3CN）]＋ 1,[Cu（Ph2Ppy）]＋ 2,[Cu2（Ph2Ppy）2（CH3CN）2]2＋ 3,[Cu2（Ph2Ppy）2（CH3CN）]2＋ 4,[Cu2（Ph2Pp...To study the Cu-Cu interaction and stability of the title complexes,the structures of complexes [Cu（Ph2Ppy）（CH3CN）]＋ 1,[Cu（Ph2Ppy）]＋ 2,[Cu2（Ph2Ppy）2（CH3CN）2]2＋ 3,[Cu2（Ph2Ppy）2（CH3CN）]2＋ 4,[Cu2（Ph2Ppy）2]2＋ 5 and [Cu2（Ph2Ppy）3（CH3CN）]2＋ 6 were calculated by density functional theory PBE0 method,and the following conclusions can be drawn：（1） There is no orbital overlapping between two Cu atoms,indicating no Cu-Cu orbital interaction exists in complexes 3～6.Due to a breakdown of the closed shell configuration of Cu atoms,the weak Cu-Cu interactions result from the 3dCu → 4sCu＇ charge-transfer in 4～6.The Cu-Cu interaction strength follows 5 〉 6 〉 4,implying that there are stronger Cu-Cu interactions in the complexes with fewer CH3CN or more Ph2Ppy ligands.（2） The calculated interaction energies suggest that the coordination of Cu to Ph2Ppy is stronger than that to CH3CN.In 3～6,there are weaker interactions between Cu and CH3CN or Ph2Ppy in the complexes with more CH3CN or Ph2Ppy ligands.（3） The P-Cu and N-Cu interactions are much stronger than the Cu-Cu interaction,so we mainly attribute the stabilities of the binuclear complexes to the eight-membered rings Cu2P2N2C2.展开更多
In order to study the Fe-Cu interactions and their effects on 31p NMR, the structures of mononuclear complex Fe（CO）3fPhzPpy）a 1 and binuclear complexes Fe（CO）3（PhEPpy）z（CuXn） （2： Xn = Cl2^2-, 3： Xn = Cl-, ...In order to study the Fe-Cu interactions and their effects on 31p NMR, the structures of mononuclear complex Fe（CO）3fPhzPpy）a 1 and binuclear complexes Fe（CO）3（PhEPpy）z（CuXn） （2： Xn = Cl2^2-, 3： Xn = Cl-, 4： Xn = Br-） are calculated by density functional theory （DFT） PBE0 method. For complexes 1, 3 and 4, the 31p NMR chemical shifts calculated by PBE0-GIAO method are in good agreement with experimental results. The 31p chemical shift is 82.10 ppm in the designed complex 2. The Fe-Cu interactions （including Fe→Cu and Fe←Cu charge transfer） mainly exhibit the indirect interactions. Moreover, the Fe-Cu（I） interactions （mostly acting as σFe-p→4Scu and aFe-C→4Scu charge transfer） in complexes 3 and 4 are stronger than Fe-Cu（Ⅱ） interactions （mostly acting as σFe-p→4Scu and σFe-p←4Sc,） in complex 2. In complex 2, the stronger Fe←Cu interac- tions, acting as σFe-p←44SCu charge transfer, increase the electron density on P nucleus, which causes the upfield 31p chemical shift compared with mononuclear complex 1. For 3 and 4, although a little deshielding for P nucleus is derived from the delocalization of σFe-p→4Scu due to the Fe→Cu interactions, the stronger σFe-c→np charge-transfer finally increases the electron density on P nucleus. As a result, an upfield 31p chemical shift is observed compared with 1. The stability follows the order of 2〉3=4, indicating that Fe（CO）3（PhzPpy）2（CuCl2） is stable and could be synthesized experimentally. The N-Cu（Ⅱ） interaction plays an important role in the stability of 2. Because the delocalization of σFe-p→4SCu and σFe-c→πc-o weakens the a bonds of Fe-C and ~r bonds of CO, it is favorable for increasing the catalytic activity of binuclear complexes. Complexes 3 and 4 are expected to show higher catalytic activity compared to 2.展开更多
基金Supported by the Natural Science Foundation of Guangdong Province (No. 5005938)Research Project of Ministry of Education and Guangdong Province,China (2007A090302046)
文摘To study the Cu-Cu interaction and stability of the title complexes,the structures of complexes [Cu（Ph2Ppy）（CH3CN）]＋ 1,[Cu（Ph2Ppy）]＋ 2,[Cu2（Ph2Ppy）2（CH3CN）2]2＋ 3,[Cu2（Ph2Ppy）2（CH3CN）]2＋ 4,[Cu2（Ph2Ppy）2]2＋ 5 and [Cu2（Ph2Ppy）3（CH3CN）]2＋ 6 were calculated by density functional theory PBE0 method,and the following conclusions can be drawn：（1） There is no orbital overlapping between two Cu atoms,indicating no Cu-Cu orbital interaction exists in complexes 3～6.Due to a breakdown of the closed shell configuration of Cu atoms,the weak Cu-Cu interactions result from the 3dCu → 4sCu＇ charge-transfer in 4～6.The Cu-Cu interaction strength follows 5 〉 6 〉 4,implying that there are stronger Cu-Cu interactions in the complexes with fewer CH3CN or more Ph2Ppy ligands.（2） The calculated interaction energies suggest that the coordination of Cu to Ph2Ppy is stronger than that to CH3CN.In 3～6,there are weaker interactions between Cu and CH3CN or Ph2Ppy in the complexes with more CH3CN or Ph2Ppy ligands.（3） The P-Cu and N-Cu interactions are much stronger than the Cu-Cu interaction,so we mainly attribute the stabilities of the binuclear complexes to the eight-membered rings Cu2P2N2C2.
基金Supported by the Natural Science Foundation of Guangdong Province (No. 5005938)
文摘In order to study the Fe-Cu interactions and their effects on 31p NMR, the structures of mononuclear complex Fe（CO）3fPhzPpy）a 1 and binuclear complexes Fe（CO）3（PhEPpy）z（CuXn） （2： Xn = Cl2^2-, 3： Xn = Cl-, 4： Xn = Br-） are calculated by density functional theory （DFT） PBE0 method. For complexes 1, 3 and 4, the 31p NMR chemical shifts calculated by PBE0-GIAO method are in good agreement with experimental results. The 31p chemical shift is 82.10 ppm in the designed complex 2. The Fe-Cu interactions （including Fe→Cu and Fe←Cu charge transfer） mainly exhibit the indirect interactions. Moreover, the Fe-Cu（I） interactions （mostly acting as σFe-p→4Scu and aFe-C→4Scu charge transfer） in complexes 3 and 4 are stronger than Fe-Cu（Ⅱ） interactions （mostly acting as σFe-p→4Scu and σFe-p←4Sc,） in complex 2. In complex 2, the stronger Fe←Cu interac- tions, acting as σFe-p←44SCu charge transfer, increase the electron density on P nucleus, which causes the upfield 31p chemical shift compared with mononuclear complex 1. For 3 and 4, although a little deshielding for P nucleus is derived from the delocalization of σFe-p→4Scu due to the Fe→Cu interactions, the stronger σFe-c→np charge-transfer finally increases the electron density on P nucleus. As a result, an upfield 31p chemical shift is observed compared with 1. The stability follows the order of 2〉3=4, indicating that Fe（CO）3（PhzPpy）2（CuCl2） is stable and could be synthesized experimentally. The N-Cu（Ⅱ） interaction plays an important role in the stability of 2. Because the delocalization of σFe-p→4SCu and σFe-c→πc-o weakens the a bonds of Fe-C and ~r bonds of CO, it is favorable for increasing the catalytic activity of binuclear complexes. Complexes 3 and 4 are expected to show higher catalytic activity compared to 2.
