New Iron(III) Bis(acetylide) Compounds Based on the Iron Cyclam Motif

New trans-[Fe(cyclam)(CCR)2]OTf compounds 2a/2b [cyclam = 1,4,8,11-tetraazacyclotetradecane, R = SiiPr3 (a) or Ph (b), and OTf = trifluoromethanesulfonate] were prepared from the reaction between trans-[Fe(cyclam)(OTf)2]OTf (1) and LiCCR. The trans arrangement of the acetylide ligands in 2 was established from the X-ray diffraction study of 2a, and the density functional theory calculations revealed significant dπ–π(CC) interactions.本研究通过反式-[Fe(cyclam)(OTf)₂]OTf（化合物1）与LiC≡CR的反应，合成了新型反式-[Fe(cyclam)(C≡CR)₂]OTf类化合物2a/2b[其中cyclam为1,4,8,11-四氮杂环十四烷，R为三异丙基硅基（SiiPr3）或苯基（Ph），OTf为三氟甲磺酸盐（trifluoromethanesulfonate）]。通过对化合物2a的X射线衍射（X-ray diffraction）分析，确证了化合物2中乙炔基配体的反式配位构型；密度泛函理论（density functional theory）计算结果显示，该体系存在显著的dπ–π(C≡C)相互作用。