通过镍(II)-硫键和碘离子基元反应有理合成碘-二硫醇盐桥联的双核镍-镍配合物

本文报道由于碘离子对不稳定的Ni(II)-S(芳基硫醇盐)键的亲核作用,使得Fe(CO)412和Ni(SR)2(dppe(SR=芳基硫醇盐)之间的反应生成NiI2(dppe).含碘和二芳基硫醇盐离子桥联的Ni-Ni双核配合物(dppe)Ni(μ-I)(μ-pdt)Ni(dppe)]I和(dppe)Ni(μ-I)(μ-edt)Ni(dppe)]I可方便地由NiI2(dppe)]和Ni(pdt)(dppe)]或Ni(edt)(dppe)]在二氯甲烷的溶液中的反应制得;该类反应可认为是由于硫醇盐离子基团中S-供体上的孤对电子对Ni-I键的进攻所致.另一方面,我们观察到FeCp(CO)2I]和Ni(pdt)(dppe)]或Ni(edt)(dppe)]在二氯甲烷中的反应极其缓慢;但当向上述反应体系中加入NH4PF6进行复分解置换后,源于碘离子和Ni(II)-S键的作用同样可得到含碘与二芳基硫醇盐离子桥联的Ni-Ni双核配合物(dppe)Ni(μ-I)(μ-pdt)Ni(dppe)]PF6和 (dppe)Ni(μ-I)(μ-edt)Ni(dppe)]PF6.实验结果说明在本文所讨认的镍(II)-硫醇盐离子-膦配合物中,Ni(II)-S键的反应活性随桥联的第二金属离子和不同的碘离子基元而改变.

Rational preparation of iodide-dithiolate-bridged binuclear Ni-Ni complex from the reaction between nickel(II)-sulfur bond and iodide moiety

The reaction between Fe(CO)412 and Ni(SR)2(dppe) affords NiI2(dppe) due to the necleophilic attack of iodide on the labile N-S(aryl thiolate) bonds.The iodide-dithiolate-bridged binuclear Ni-Ni complexes(dppe)Ni(μ-I)(μ-pdt)Ni(dppe)]I and(dppe)Ni(μ-I)(μ-edt)Ni(dppe)]I can be readily prepared by reaction betweenNiI2(dppe)]andNi(pdt)(dppe)] orNi(edt)(dppe)]dppe=1,2-bis (diphenyl phosphino)-ethane;pdt=1,3-propane-dithiolate;edt=1,2-ethane-dithiolate]in CH2C12 as a result of the attack on the Ni-I bond by the lone pairs of electrons on thiolato sulfur donors.On the other hand,the reaction betweenFeCp(CO)2I] and Ni(pdt)(dppe)] orNi(edt)(dppe)]in CH2C12 processes extremely slow.However, upon the metathesis with NH4PF6 for these reaction,the iodide-thiolate-bridged binuclear Ni-Ni complexes (dppe)Ni(μ-I)(μ-pdt)Ni(dppe)]PF6 and (dppe)Ni(μ-I)(μ-edt)Ni(dppe)]PF6 have been prepared due to the reaction of iodide and the Ni(II)-S bonds.These results suggest that the reactivity of Ni-SR bonds in such Ni-thiolate-phosphine complexes is tuneable with regard to the second metal ion and the different reactivity of iodide moiety.