Metallacycles of 1,4-Bis(3-thiophenyl)-1,3-butadiyne in Mixed Metal Clusters Derived by C−C Bond Coupling of Alkynyls

Reaction of cis-Pt(C⋮CTp)2(dppe) (Tp = thiophene) with Ru3(CO)11(CH3CN) in refluxing toluene
for 1 h resulted in head-to-head C−C bond coupling of the alkynyl ligands forming 1,4-bis(3-thiophenyl)buta-1,3-diyne, which afforded an extraordinal 1,4-heterodimetalla[5,6-b]thienopentalene, [PtRu3{μ4-η1:η1:η1:η1:η4:η4-C4H2S-CCC(H)CTp}(μ-CO)2(CO)6(dppe)] (1) (Tp = 3-thiophene), in 54% yield.
Its crystal structure shows that a hydrogen shift occurs from the thiophene substituent to an end carbon
atom of the 1,3-diyne, transforming 1,4-bis(3-thiophenyl)buta-1,3-diene, which results in formations of
PtC4 and RuC4 rings, both with metallacyclopenta-2,4-diene. The Ru3(μ-CO)2(CO)6 moiety conforms to
an open cluster, and its central ruthenium atom forms a RuCp ring whose carbon atoms bond to two
ruthenium atoms by eight Ru−C π-bonds. Reactions of the acetylides with single metal media, Fe(CO)5,
gave rise to annealation of alkynyls via both cyclic and acyclic dimerization processes, affording
extraordinal metallacycles of 1,3-diyne, a platinacyclobutene consisting of a cyclone, [FePt{μ2-η1:η1:η4-(C4Tp2-CO)-CO}(CO)3(dppe)] (2), and a 1,2-heterodimetallacyclo-3-penten-5-one, [FePt(μ2-η1:η1:η2-TpCCCCTp-CO)(μ-CO)(CO)2](dppe)] (3), in 15 and 16% yields, respectively.

顺式-Pt(C≡CTp)₂(dppe)（Tp=噻吩(thiophene)）与Ru₃(CO)₁₁(CH₃CN)在回流甲苯中反应1小时，其炔基配体发生头对头C−C键偶联，生成1,4-双(3-噻吩基)丁-1,3-二炔，进而以54%的产率得到罕见的1,4-异二金属[5,6-b]噻吩并戊搭烯配合物[PtRu₃{μ₄-η¹:η¹:η¹:η¹:η⁴:η⁴-C₄H₂S-C=CC(H)=CTp}(μ-CO)₂(CO)₆(dppe)]（1）（Tp=3-噻吩基）。
该配合物的晶体结构表明，氢原子从噻吩取代基迁移至1,3-二炔的末端碳原子，使1,4-双(3-噻吩基)丁-1,3-二烯发生结构转化，最终形成两个均含金属环戊-2,4-二烯(metallacyclopenta-2,4-diene)结构的PtC₄与RuC₄环。
其中Ru₃(μ-CO)₂(CO)₆结构单元为开放式簇合物，其中心钌原子形成RuCp环，该环的碳原子通过8条Ru−C π键与另外两个钌原子相连。
该炔基金属试剂与单金属介质五羰基铁(Fe(CO)₅)的反应，通过环化与非环二聚过程实现炔基的环化转化，得到两类1,3-二炔类异金属杂环化合物：含环酮结构的铂杂环丁烯配合物[FePt{μ₂-η¹:η¹:η⁴-(C₄Tp₂-CO)-CO}(CO)₃(dppe)]（2），以及1,2-异二金属环-3-戊烯-5-酮配合物[FePt(μ₂-η¹:η¹:η²-TpCCCC Tp-CO)(μ-CO)(CO)₂](dppe)]（3），二者产率分别为15%与16%。