Brittingham K A, Espenson J H
Ames Laboratory and the Department of Chemistry, Iowa State University of Science and Technology, Ames, Iowa 50011, USA.
Inorg Chem. 2001 Jun 4;40(12):2730-6. doi: 10.1021/ic001188q.
Mononuclear Re(V) compounds MeReO(mtp)NC(5)H(4)X, 3, where mtpH(2) is 2-(mercaptomethyl)thiophenol have been prepared from the monomerization of MeReO(mtp) by pyridines with electron-donating substituents in the para or meta position; X = 4-Me, 4-Bu(t), 3-Me, 4-Ph, and H. Analogous compounds, MeReO(edt)N(5)H(4)X, 4, edtH(2) = 1,2-ethanedithiol, were prepared similarly. The equilibrium constants for the reaction, dimer + 2Py = 2M-Py, are in the range (2.5-31.6) x 10(2) L mol(-1). Both groups of monomeric compounds react with quinones (phenanthrenequinone, PQ, and 3,5-tert-butyl-1,2-benzoquinone, DBQ), displacing the pyridine ligand and forming Re(VII) catecholate complexes MeReO(dithiolate)PCat and MeReO(dithiolate)DBCat. With PQ, the reaction MeReO(dithiolate)Py + PQ = MeReO(dithiolate)PCat + Py is an equilibrium; values of K(Q) for different Py ligands lie in the ranges 9.2-42.7 (mtp) and 3.2-11.2 (edt) at 298 K. These second-order rate constants (L mol(-1) s(-1)) at 25 degrees C in benzene were obtained for the PQ reactions: k(f) = (5.3-15.5) x 10(-2) (mtp), (6.6-16.4) x 10(-2) (edt); k(r) = (3.63-5.71) x 10(-3) (mtp), (14.7-22.0) x 10(-3) (edt). The ranges in each case refer to the series of pyridine ligands, the forward rate constant being the largest for C(5)H(5)N, with the lowest Lewis basicity. The reactions of MeReO(dithiolate)Py with DBQ proceed to completion. Values of k(f)/L mol(-1) s(-1) fall in a narrow range, 4.02 (X = Bu(t)) to 8.4 (X = H) with the dithiolate being mtp.
单核铼（V）化合物MeReO(mtp)NC₅H₄X（3），其中mtpH₂为2-(巯基甲基)苯硫酚，是通过[MeReO(mtp)]₂与在对位或间位带有供电子取代基的吡啶单体化制备而成；X = 4-Me、4-Bu(t)、3-Me、4-Ph和H。类似的化合物MeReO(edt)N₅H₄X（4），edtH₂ = 1,2 - 乙二硫醇，也是通过类似方法制备的。反应二聚体 + 2Py = 2M - Py的平衡常数在(2.5 - 31.6)×10² L mol⁻¹范围内。这两组单体化合物都与醌（菲醌，PQ，和3,5 - 叔丁基 - 1,2 - 苯醌，DBQ）反应，取代吡啶配体并形成铼（VII）儿茶酚配合物MeReO(二硫醇盐)PCat和MeReO(二硫醇盐)DBCat。与PQ反应时，MeReO(二硫醇盐)Py + PQ = MeReO(二硫醇盐)PCat + Py是一个平衡反应；在298 K时，不同Py配体的K(Q)值在9.2 - 42.7（mtp）和3.2 - 11.2（edt）范围内。在25℃的苯中，针对PQ反应得到了这些二级速率常数（L mol⁻¹ s⁻¹）：k(f) = (5.3 - 15.5)×10⁻²（mtp），(6.6 - 16.4)×10⁻²（edt）；k(r) = (3.63 - 5.71)×10⁻³（mtp），(14.7 - 22.0)×10⁻³（edt）。每种情况下的范围指的是吡啶配体系列，正向速率常数对于C₅H₅N最大，其路易斯碱性最低。MeReO(二硫醇盐)Py与DBQ的反应进行完全。k(f)/L mol⁻¹ s⁻¹的值落在一个狭窄范围内，对于二硫醇盐为mtp时，从4.02（X = Bu(t)）到8.4（X = H）。
