A series of rigid-rod alkynylferrocenyl precursors with oligothiophene (from thiophene to terthiophene) linkage units in the backbone, [(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)mBr] 2a–2c, [(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)mCCSiMe3] 3a–3c and [(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)mCCH] 4a–4c (m
= 1–3), have been prepared in moderate to good yields. The ferrocenylacetylene complexes 4a–4c
can be used to form a range of stable platinum(II) alkynyl and bis(alkynyl) compounds trans-[(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)mCCPt(PEt3)2Ph] 5a–5c and trans-[(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)mCCPt(PBu3)2CC(C4H2S)mCC(η5-C5H4)Fe(η5-C5H5)] 6a–6c (m
= 1–3). All these new compounds have been fully characterized by analytical and spectroscopic methods and the molecular structures of the bithienyl-linked
complexes [(η5-C5H5)Fe(η5-C5H4)CC(C4H2S)2CC(η5-C5H4)Fe(η5-C5H5)], 2b, 4b, 5b and 6b have been established by X-ray crystallography. Structural analysis of 6b confirms its rigid-rod structural motif, featuring coplanar bithienyl rings and a trans arrangement of the two bithiophene groups. An iron–iron through-space distance of ca. 32 Å is observed in 6b. Although there is no significant metallocene–metallocene interaction through the alkynyl–platinum–oligothiophene bridge, a slight negative shift
of the ferrocene–ferrocenium redox potential in the platinum-containing species indicates some degree of electron delocalization into the platinum segment, in line with the results from theoretical studies. Oxidation of the thiophene units is facilitated by the presence of the platinum centre and increased conjugation in the chain.
一系列具有刚性结构的主链含
噻吩链联接单元(-(C$_4}$H$_2}$S)$_m$-Br, m=1~3)的炔基
二茂铁前驱体[(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_m$Br]2a–2c, [(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_m$CCSiMe$_3}$]3a–3c 和 [(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_m$CCH]4a–4c 已被合成并分离得到中等到良好的收率。炔基
二茂铁配合物4a–4c 可以用来合成一系列稳定的含 Pt(II)炔基和双炔基化合物trans-[(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_m$CCPt(PEt$_3}$)$_2$Ph]5a–5c,和 trans-[(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_m$CCPt(PBu$_3}$)$_2$CC(C$_4}$H$_2}$S)$_m$CC(η$^5$-C$_5}$H$_4}$)Fe(η$^5$-C$_5}$H$_5$)]6a–6c (m = 1~3)。所有这些新化合物经由分析和光谱方法进行了全面的鉴定,双
噻吩联接配合物[(η$^5$-C$_5}$H$_5$)Fe(η$^5$-C$_5}$H$_4}$)CC(C$_4}$H$_2}$S)$_2$CC(η$^5$-C$_5}$H$_4}$)Fe(η$^5$-C$_5}$H$_5$)]的 2b, 4b, 5b 和 6b 的分子结构由 X-射线单晶衍射法确立。结构分析确认 6b 具有刚性棒结构, 特征为双
噻吩环共面与双
噻吩基团顺式排列。在 6b 中观察到
铁—
铁之间空间的距离为 3.2 Å。虽然没有通过炔基—
铂—
噻吩链检测到明显的
金属茂-
金属茂相互作用,在含
铂化合物中
二茂铁-
二茂铁正离子的氧化还原电位小负移表明有某种程度的电子离域到
铂片段,与由理论研究得到的结果相一致。在链中增加的共轭及由于存在
铂中心使
噻吩单元易于被氧化。