233604-03-0Relevant academic research and scientific papers
Bimetallic complexes with conjugated C4, C6, C10, and C14 bridges: Synthetic routes to alkynediyl-bridged bis(carbene) complexes
Hartbaum, Cornelia,Mauz, Elvira,Roth, Gerhard,Weissenbach, Kerstin,Fischer, Helmut
, p. 2619 - 2627 (1999)
The reaction of [(CO)5W=C(Ph)H] with Me2NC≡CNMe2 affords two complexes: the binuclear complex [(CO)5W=C(NMe2)(Me2N)C=W(CO)5] (2) and the insertion product [(CO)5W=C(NMe2)C(NMe2)=C(Ph)H] (3). Sequential reaction of the (dimethylamino)-ethynylcarbene complex [(CO)5W=C(NMe2)C≡CH] (4a) with nBuLi, W(CO)6, and F3CSO3-Me yields the new ethynediyl-bridged binuclear alkoxycarbene-aminocarbene complex [(CO)5W=C(NMe2)C≡C(MeO)C=W(CO)5] (5). Treatment of 4a and of [(CO)5Cr=C(NMe2)C≡ CH] (4b) with nBuLi and iodine gives the new iodine-substituted complexes [(CO)5M= C(NMe2)C≡CI] (M = W (6a), M = Cr (6b)). By Pd-catalyzed coupling of 6a,b with the C-stannylated ethynylcarbene complexes [(CO)5M=C(NMe2)C≡CSn(nBu)3] (7a,b) the butadiynediyl-bridged bis(carbene) complexes [(CO)5M=C(NMe2)(C≡C)2(Me 2N)C=M(CO)5] (8a,b) are obtained. Analogously, from [(CO)5W=C(NMe2)(C≡C)xH] (x = 2, 3) and nBuLi/I2 amino(iodobutadiynyl)carbene and amino(iodohexatriynyl)carbene complexes [(CO)5W= C(NMe2)(C≡C)xI] (x = 2 (10), 3 (14)) are obtained. Pd-catalyzed coupling with the corresponding C-stannylated alkynylcarbene complexes finally affords the binuclear C10-(NMe2)2- and C14(NMe2)2-bridged complexes [(CO)5W=C(NMe2)(C≡C)x(Me 2N)C=W(CO)5] (x = 4 (12), 6 (16)). All alkynediyl-bridged bis(carbene) complexes are stable at room temperature. The spectroscopic data of 5 indicate that it is best described as a hybrid of a dipolar allenyl-type compound and an alkynylcarbene complex. In contrast, the C≡C units in the binuclear complexes 8a,b, 12, and 16 are essentially localized.
