Ding Yan, Wu Wengan, Fanwick Phillip E., Walton Richard A.
Department of Chemistry, Purdue University, 1393 Brown Building, West Lafayette, Indiana 47907-1393.
Inorg Chem. 1999 Apr 19;38(8):1918-1928. doi: 10.1021/ic981192q.
The reactions of the multiply bonded dirhenium(II) complexes Re(2)Cl(4)(&mgr;-dppm)(2)(CO), Re(2)Cl(4)(&mgr;-dppm)(2)(CO)(CNXyl), and [Re(2)Cl(3)(&mgr;-dppm)(2)(CO)(CNXyl)(2)]O(3)SCF(3) (dppm = Ph(2)PCH(2)PPh(2); Xyl = 2,6-dimethylphenyl) with the requisite number of equivalents of TlO(3)SCF(3) and XylNC lead to three, non-interconvertible, structural isomers of the complex Re(2)Cl(2)(&mgr;-dppm)(2)(CO)(CNXyl)(3)(2) (4a, 5a, and 6a; a signifies a triflate salt). Each of these complexes undergoes two reversible one-electron reductions which afford the redox pairs 4a'/4' ', 5a'/5' ', and 6a'/6' ', respectively. While 4a' and 4' ' have structures which are very similar to that of 4a, the complexes 5a'/5' ' and 6a'/6' ' have structures which differ from 5a and 6a, thereby establishing the existence of coupled redox/isomerization reactions. Solutions of 6a' in acetonitrile and 6' ' in benzene slowly convert to the new isomers 7a' and 8' ', respectively, which are in turn found to be members of the redox series 7'/7' ' and 8/8'/8' '. In all, the Re(2)Cl(2)(&mgr;-dppm)(2)(CO)(CNXyl)(3) species (n = 2, 1, or 0) have been found to exist in seven distinct structural forms which possess Re-Re bond orders of 3, 2, 1.5, 1, or 0 depending on the specific bioctahedral structure which is assumed and the charge on the complex. Single-crystal X-ray structure determinations have been carried out on the seven complexes 4' ', 5a, 6a, 6a', 6' ', 7a', and 7' '.
多重键合的二铼（II）配合物Re₂Cl₄(μ-dppm)₂(CO)、Re₂Cl₄(μ-dppm)₂(CO)(CNXyl)和[Re₂Cl₃(μ-dppm)₂(CO)(CNXyl)₂]O₃SCF₃（dppm = Ph₂PCH₂PPh₂；Xyl = 2,6-二甲基苯基）与所需当量的TlO₃SCF₃和XylNC反应，生成配合物Re₂Cl₂(μ-dppm)₂(CO)(CNXyl)₃₂的三种不可相互转化的结构异构体（4a、5a和6a；a表示三氟甲磺酸盐）。这些配合物中的每一种都经历两个可逆的单电子还原反应，分别生成氧化还原对4a'/4''、5a'/5''和6a'/6''。虽然4a'和4''的结构与4a非常相似，但配合物5a'/5''和6a'/6''的结构与5a和6a不同，从而证实了耦合氧化还原/异构化反应的存在。6a'在乙腈中的溶液和6''在苯中的溶液分别缓慢转化为新的异构体7a'和8'''，结果发现它们是氧化还原系列7'/7''和8/8'/8''的成员。总之，已发现Re₂Cl₂(μ-dppm)₂(CO)(CNXyl)₃物种（n = 2、1或0）以七种不同的结构形式存在，根据所假设的特定双八面体结构和配合物上的电荷，其Re-Re键级分别为3、2、1.5、1或0。已对七种配合物4''、5a、6a、6a'、6''、7a'和7''进行了单晶X射线结构测定。
