''Dialkylidyne'' (mu-dicarbido) complexes (RO)3W = C-C = W(OR)3 (OR = OCMe3, 1; OCMe2CF3, 2; OCMe2Et, 3) have been synthesized. A single crystal X-ray diffraction study performed on the t-butoxy complex 1 demonstrates that the molecule exists in a staggered D3d form in the solid state at -50-degrees-C. Complex 1 crystallizes in the rhombohedral space group R3BAR, a = 11.301(4) angstrom, alpha = 52.93(3)-degrees, Z = 1. Data were collected in the omega-2-theta-mode and refined to R = 0.039 and R(w) = 0.055. Absorption spectra of 1-3 in 2-methylpentane show a surprisingly large number of transitions as compared to the alkylidyne Me3CC = W(OCMe3)3 and the triply bonded dimer W2(OCMe3)6; while assigning the bands is not currently feasible due to the three-fold symmetry of the molecules, these observations suggest that the pi-clouds in 1-3 are conjugated in the excited state rather than localized.
合成了一种二烃基底(mu-二碳化)复合物(RO)₃W=C-C=W(OR)₃(OR=OCMe₃,1;OCMe₂CF₃,2;OCMe₂Et,3)。对t-丁氧基复合物1进行单晶X射线衍射研究,结果表明该分子在-50℃的固态下以D₃d形式存在,该结构具有季
戊烷骨架的畸变性。复合物1在菱方晶系空间群R₃B ARP中 crystallizes,a=11.301(4)Å,α=52.93(3),Z=1。数据采用ω-2θ模式收集,并以R=0.039和R(w)=0.055进行了精修。在
2-甲基戊烷中1-3的吸收光谱显示,与烷基基底Me₃CC=W(OCMe₃)₃和三键二聚体W₂(OCMe₃)₆相比,其电荷跃迁数目异常繁多;尽管由于分子的三重对称性,目前无法对这些谱带进行明确归属,但这一观察表明复合物1-3的π电子云在激发态呈现共轭性而不显局部化。