Adams Richard D, Dhull Poonam, Kaushal Meenal, Smith Mark D
Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States.
Inorg Chem. 2019 May 6;58(9):6008-6015. doi: 10.1021/acs.inorgchem.9b00328. Epub 2019 Apr 12.
The reaction of Re(CO)(μ-CH)(μ-H) (1) with furan in CHCl at 40 °C yielded two new isomeric dirhenium compounds, Re(CO)(μ-η-2,3-CHO)(μ-H) (2) and Re(CO)(μ-η-3,2-CHO)(μ-H) (3), which contain a bridging (σ + π)-coordinated furyl ligand formed by activation of the C-H bond at the 2 and 3 positions of furan, respectively. Compound 3 is the first example of a compound formed by C-H bond activation at the 3 position of a furan ring. Compound 3 was isomerized to 2 by heating to 80 °C for 7 days. The reaction of compound 2 with a second 1 equiv of 1 in CHCl at 40 °C yielded the doubly metalated furan-bis[Re(CO)(μ-H)] product Re(CO)(μ-H) (4) containing a 2,5-furdiyl ligand that is (σ + π)-coordinated to two Re(CO)(μ-H) groups by activation of the C-H bond at the 5 position of the furyl ligand in 2. Compound 2 can also be formed as the major isomer, together with a small quantity of 4 by heating furan with Re(CO)(μ-H)[μ-η-C(H)═C(H)Bu ] in toluene to reflux. An isomer of 4, Re(CO)(μ-H) (5), was obtained from the reaction of 3 with 1 through C-H activation at the 4 position of the furyl ring in 3. Compound 4 was also obtained from 5 by heating to 110 °C for 24 h. The reaction of 1 with 2,5-dimethylfuran (DMFUR) in CHCl at 40 °C yielded the new compound Re(CO)(μ-η-3,2-(CH)CHO) (6), which contains a bridging (σ + π)-coordinated 2,5-dimethylfuryl ligand formed by activation of the C-H bond at the 3 position of DMFUR. All of the new compounds were characterized structurally by single-crystal X-ray diffraction analysis.
Re(CO)(μ-CH)(μ-H) (1) 与呋喃在40 °C的CHCl₃中反应，生成了两种新的异构二铼化合物，Re(CO)(μ-η-2,3-CHO)(μ-H) (2) 和Re(CO)(μ-η-3,2-CHO)(μ-H) (3)，它们分别通过活化呋喃2位和3位的C-H键形成了一个桥连的(σ + π)配位的呋喃基配体。化合物3是呋喃环3位C-H键活化形成的化合物的首个例子。化合物3在80 °C加热7天异构化为2。化合物2与1当量的1在40 °C的CHCl₃中反应，生成了双金属化的呋喃-双[Re(CO)(μ-H)]产物Re(CO)(μ-H) (4)，该产物含有一个2,5-呋喃二基配体，通过活化2中呋喃基配体5位的C-H键与两个Re(CO)(μ-H)基团(σ + π)配位。化合物2也可以作为主要异构体，与少量的4一起通过在甲苯中加热呋喃与Re(CO)(μ-H)[μ-η-C(H)═C(H)Bu]回流得到。4的一个异构体，Re(CO)(μ-H) (5)，是由3与1通过活化3中呋喃基环4位的C-H键反应得到的。化合物4也可以通过将5加热到110 °C 24小时得到。1与2,5-二甲基呋喃(DMFUR)在40 °C的CHCl₃中反应，生成了新化合物Re(CO)(μ-η-3,2-(CH)CHO) (6)，它含有一个通过活化DMFUR 3位的C-H键形成的桥连的(σ + π)配位的2,5-二甲基呋喃基配体。所有新化合物均通过单晶X射线衍射分析进行了结构表征。
