School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia5005.
Dalton Trans. 2010 Feb 7;39(5):1222-34. doi: 10.1039/b909708b. Epub 2009 Nov 19.
Reactions of CCo3 carbonyl clusters Co3(mu3-CR)(CO)9 with 2,4,6-trimethyl-1,3,5-trithiane (SMe3) have given Co3(mu3-CR)(mu3-SMe3)(CO)6 [R = H (1), C[triple bond]CSiMe3 (2)]. A small amount of the coupled-alkyne product Me3SiC2[Co2(CO)6]C2[Co2(mu-SMe3)(CO)4]C[triple bond]CSiMe3 (3) was isolated from the latter reaction. The reaction of Co3(mu3-CC[triple bond]CSiMe3)(mu3-SMe3)(CO)6 (2) with AuCl(PPh3) in the presence of NaOMe gave Co3{mu3-CC[triple bond]CAu(PPh3)}(mu3-SMe3)(CO)6 (4), which in turn reacts with Co3(mu3-CBr)(CO)9 in the presence of catalytic amounts of Pd(PPh3)4 and CuI to give {(OC)9Co3}(mu-C[triple bond]CC[triple bond]C){Co3(mu3-SMe3)(CO)6} (5). Further substitution of 5 with SMe3 gave symmetrical {Co3(mu3-SMe3)(CO)6}2(mu-C[triple bond]CC[triple bond]C) (6), also obtained from a reaction between {Co3(CO)9}2(mu-C[triple bond]CC[triple bond]C) and two equivalents of SMe3. Similar substitution of Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(CO)9 with SMe3 gave Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(mu3-SMe3)(CO)6 (7). In all of these compounds, the SMe3 ligand caps the basal face of the CCo3 cluster on the opposite side to the mu3-CR group. The three S donors occupy axial sites, with all CO groups being in equatorial sites. Reactions of Co3(mu3-CBr)(CO)9 with SMe3 gave only Co3(mu3-CX)(mu3-SMe3)(CO)6 [X = C(O)NMe2 (8), CO2H (9)]. The redox properties and electronic structure of the C4-bridged bis-cluster 6 have been investigated through a combination of cyclic voltammetry, IR spectroelectrochemistry and DFT calculations, with comparisons made with suitable model systems. Single-crystal X-ray diffraction structure determinations of 1, 2, 3, 4 and 8 are reported.
CCo3 羰基簇 Co3(mu3-CR)(CO)9 与 2,4,6-三甲基-1,3,5-三硫杂环戊烷(SMe3)的反应得到了 Co3(mu3-CR)(mu3-SMe3)(CO)6[R = H(1), C[triple bond]CSiMe3(2)]。从后者的反应中分离出少量偶联炔烃产物 Me3SiC2[Co2(CO)6]C2[Co2(mu-SMe3)(CO)4]C[triple bond]CSiMe3(3)。Co3(mu3-CC[triple bond]CSiMe3)(mu3-SMe3)(CO)6(2)与 AuCl(PPh3)在 NaOMe 的存在下反应得到了 Co3{mu3-CC[triple bond]CAu(PPh3)}(mu3-SMe3)(CO)6(4)，后者在催化量的 Pd(PPh3)4 和 CuI 的存在下与 Co3(mu3-CBr)(CO)9 反应得到{(OC)9Co3}(mu-C[triple bond]CC[triple bond]C){Co3(mu3-SMe3)(CO)6}(5)。进一步用 SMe3 取代 5 得到了对称的{Co3(mu3-SMe3)(CO)6}2(mu-C[triple bond]CC[triple bond]C)(6)，也可以通过{Co3(CO)9}2(mu-C[triple bond]CC[triple bond]C)与两个当量的 SMe3 之间的反应得到。Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(CO)9 用 SMe3 进行类似的取代得到了 Co3{mu3-C(C[triple bond]C)2[Ru(dppe)Cp*]}(mu3-SMe3)(CO)6(7)。在所有这些化合物中，SMe3 配体在与 mu3-CR 基团相对的 CCo3 簇的基底面上封闭了羰基。三个 S 供体占据轴向位置，所有 CO 基团都位于赤道位置。Co3(mu3-CBr)(CO)9 与 SMe3 的反应仅得到 Co3(mu3-CX)(mu3-SMe3)(CO)6[X = C(O)NMe2(8), CO2H(9)]。通过循环伏安法、IR 光谱电化学和 DFT 计算相结合，研究了 C4-桥联双簇 6 的氧化还原性质和电子结构，并与合适的模型系统进行了比较。报道了 1、2、3、4 和 8 的单晶 X 射线衍射结构测定。
