Reaction of the Tellurium-Capped Triiron Cluster [TeFe₃(CO)₉]^2- with the Bifunctional Propargyl Bromide: Formation of a Series of Novel Organic Te−Fe−CO Complexes

When [TeFe3(CO)9]2- was treated with 1 equiv of propargyl bromide in MeCN, the novel acyl complex [Et4N][(μ3-Te)Fe3(CO)9(μ3-η1:η1:η3-C(O)C(H)CCH2)] ([Et4N][1]) was obtained. Cluster 1 can be viewed to consist of a TeFe3 core which is linked by the novel allylcarbonyl ligand C(O)CHCCH2 in a μ3-η1:η1:η3 fashion. Further oxidation of cluster 1 occurs via organo ligand loss and bond rearrangement to give the oxidation product Te2Fe3(CO)9. In addition, when cluster 1 was methylated with CF3SO3Me, the Fischer-type carbene complex (μ3-Te)Fe3(CO)9(μ3-η1:η1:η3-C(OMe)C(H)CCH2) (2) was afforded. When the ratio of reactants and reaction solvent was varied, the detailed reaction of [TeFe3(CO)9]2- with propargyl bromide could be further investigated. When [TeFe3(CO)9]2- was treated with excess propargyl bromide in MeCN, the two new butterfly clusters Te2Fe2(CO)6(CHCCH2)2 (3) and Te2Fe2(CO)6(CH2C⋮CH)(CHCCH2) (4) were obtained along with cluster 1. While cluster 3 displays a Te2Fe2 metal core with two allenyl ligands attached to the tellurium atoms in anti positions, cluster 4 consists of a Te2Fe2 core with each tellurium atom coordinated to one allenyl or one propargyl ligand in an anti position. Further investigation of [TeFe3(CO)9]2- with propargyl bromide in a molar ratio of 1:2 or 1:4 in CH2Cl2 showed that the oxidation product (μ3-Te)Fe3(CO)9(μ3-η1:η2:η1-C(Me)CH) (5) was afforded, in addition to the formation of 1, 3, and 4. Cluster 5 can be viewed to be composed of a TeFe3 core coordinated with the propyne ligand C(Me)⋮CH, which acts as a 4e donor. This paper describes the detailed reactions of [TeFe3(CO)9]2- with the bifunctional propargyl bromide in terms of the reaction solvents, the ratio of the reactants, and the chalcogen effect, and the reactivities and structural features of the resultant clusters with the novel organo moieties are systematically compared and discussed.在乙腈（MeCN）中，将[TeFe₃(CO)₉]²⁻与1当量炔丙基溴反应，可得到新型酰基配合物[Et₄N][(μ₃-Te)Fe₃(CO)₉(μ₃-η¹:η¹:η³-C(O)C(H)CCH₂)]（记为[Et₄N][1]）。簇合物1可被视为由TeFe₃金属核构成，该核通过μ₃-η¹:η¹:η³配位模式的新型烯丙基羰基配体C(O)CHCCH₂进行桥联。对簇合物1进行进一步氧化时，会通过有机配体解离与键重排过程，生成氧化产物Te₂Fe₃(CO)₉。此外，利用三氟甲磺酸甲酯（CF₃SO₃Me）对簇合物1进行甲基化反应，可得到费希尔型卡宾配合物(μ₃-Te)Fe₃(CO)₉(μ₃-η¹:η¹:η³-C(OMe)C(H)CCH₂)（记为2）。通过改变反应物投料比与反应溶剂，可进一步研究[TeFe₃(CO)₉]²⁻与炔丙基溴的详细反应历程。在乙腈（MeCN）中，将[TeFe₃(CO)₉]²⁻与过量炔丙基溴反应，可得到簇合物1以及两种新型蝶形簇合物：Te₂Fe₂(CO)₆(CH=C=CH₂)₂（记为3）与Te₂Fe₂(CO)₆(CH₂C≡CH)(CH=C=CH₂)（记为4）。簇合物3具有Te₂Fe₂金属核，两个联烯配体以反式位置配位至碲原子上；而簇合物4的Te₂Fe₂核中，每个碲原子分别以反式位置配位一个联烯配体或一个炔丙基配体。在二氯甲烷（CH₂Cl₂）中，以1:2或1:4的摩尔比让[TeFe₃(CO)₉]²⁻与炔丙基溴反应时，除生成1、3与4外，还可得到氧化产物(μ₃-Te)Fe₃(CO)₉(μ₃-η¹:η²:η¹-C(Me)=CH)（记为5）。簇合物5可被视为由TeFe₃金属核与作为4电子给体的丙炔配体C(Me)≡CH配位构成。本文从反应溶剂、反应物投料比以及硫族元素效应三个维度，详细阐述了[TeFe₃(CO)₉]²⁻与双功能炔丙基溴的反应历程，并对所得含新型有机官能团簇合物的反应活性与结构特征进行了系统对比与讨论。