COOPERATIVE REACTIVITY IN THE INTERACTIONS OF X-H BONDS WITH A ZIRCONIUM-IRIDIUM BRIDGING IMIDO COMPLEX
COOPERATIVE REACTIVITY IN THE INTERACTIONS OF X-H BONDS WITH A ZIRCONIUM-IRIDIUM BRIDGING IMIDO COMPLEX
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DOI：
10.1021/ja00088a019
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发表时间：
1994-05-04
影响因子：
15
通讯作者：
BERGMAN, RG
中科院分区：
文献类型：
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作者：
BARANGER, AM;BERGMAN, RG
报道了第一个早-晚杂环桥联亚胺配合物Cp（2）Zr（mu-N-t-Bu）-IrCp*（1）的合成。通过将n-BuLi和Cp*IrN-t-Bu依次加成到Cp（2）ZrCl（2）中，合成了配合物1，产率为65%，并通过X射线衍射研究进行了表征。发现Ir-Zr键距为2.598（2）埃，Ir-N（1.887（13）埃）和Zr-N（2.084（13）埃）键距与在类似的均亚氨基二聚体中观察到的键距相当。发现亚胺配合物1经历极性（N-H，O-H，S-H）和非极性（H-H，Si-H，C-H）X-H键跨越Ir-Zr键的加成。例如，亚胺配合物1与对甲苯胺反应生成Cp（2）Zr（NHAr）（mu-N-t-Bu）（mu-H）IrCp*（2，60%产率），加入对甲酚得到Cp（2）Zr（OAr）（mu-N-t-Bu）（mu-H）IrCp*（3a，56%产率），加入叔丁醇导致Cp（2）Zr（O-t-Bu）（mu-N-t-Bu）（mu-H）IrCp*（3b，74%产率），加入丙酮得到Cp（2）Zr（OC（CH 2）CH 3）（mu-N-t-Bu）（mu-H）IrCp*（4，72%产率）。配合物2和3a的结构经X-射线单晶衍射表征。加入对-硫代甲酚得到两种产物，5a和5 b。发现主要产物在光谱学上与对甲苯胺、对甲酚、叔丁醇和丙酮加成产物相似，表明具有相似的配方（Cp（2）Zr（SAr）（mu-N-t-Bu）（mu-H）IrCp*）。向1中加入H2S导致形成桥连硫化物络合物Cp（2）Zr（μ L-N-t-Bu）（μ-S）IrCp*（6，45%产率），推测是通过类似的X-H加成，然后消除H-2。将二乙基膦和环己基膦加入到亚氨基络合物1中导致磷化物（PR（2））不寻常地插入Ir-N而不是Ir-Zr键中，得到Cp（2）Zr（μ-N（t-Bu）PEt（2））Ir（H）Cp*（8a，63%产率）和Cp（2）Zr（μ-N（t-Bu）PHCy）Ir（H）Cp*（8b，50%产率）。对8a进行X射线衍射研究，其揭示Ir-Zr键距为2.642（1）埃，与亚氨基络合物1中的键距相当。叔丁醇盐络合物3b与MeOTf反应，得到CpZr（O-t-Bu）（OTf）（mu-H）（mu-N-t-Bu）IrCp*（11，62%产率），其是由用三氟甲磺酸酯配体置换单个Zr键合的Cp配体得到的产物。X射线衍射研究证实，三氟甲磺酸根离子共价键合到锆上。将三甲基膦加入到叔丁醇盐络合物3b中导致亚氨基和氢化物桥的还原消除，得到Cp（2）Zr（O-t-Bu）（NH-t-Bu）（12，58%产率）和Cp*Ir（PMe（3））（2）（84%产率）。将H-2加成到1上导致H-H键在Ir-Zr键上可逆加成，形成Cp（2）Zr（H）（mu-N-t-Bu）（mu-H）IrCp*（9a，69%产率）。末端和桥连的碳原子相互交换，并与过量的H-2交换。将MePhSiH（2）加成到1中得到Cp（2）Zr（SiHMePh）（mu-N-t-Bu）（mu-H）IrCp*（10），其产物类似于由H-2加成得到的产物。
We report the synthesis of the first early-late heterobimetallic bridging imido complex Cp(2)Zr(mu-N-t-Bu)-IrCp* (1). Complex 1 was synthesized in 65% yield by the sequential addition of n-BuLi and Cp*IrN-t-Bu to Cp(2)ZrCl(2) and was characterized by an X-ray diffraction study. The Ir-Zr bond distance was found to be 2.598(2) Angstrom, and the Ir-N (1.8 87(13) Angstrom) and Zr-N (2.084(13) Angstrom) bond distances are comparable to those observed in analogous homonuclear imido dimers. Imido complex 1 was found to undergo addition of both polar (N-H, O-H, S-H) and nonpolar (H-H, Si-H, C-H) X-H bonds across the Ir-Zr bond. For example, the reaction of imido complex 1 with p-toluidine resulted in the formation of Cp(2)Zr(NHAr)(mu-N-t-Bu) (mu-H)IrCp* (2, 60% yield), the addition of p-cresol gave Cp(2)Zr(OAr)(mu-N-t-Bu)(mu-H) IrCp* (3a, 56% yield), the addition of tert-butyl alcohol led to Cp(2)Zr(O-t-Bu)(mu-N-t-Bu)(mu-H) IrCp* (3b, 74% yield), and the addition of acetone yielded Cp(2)Zr(OC(CH2)CH3)(mu-N-t-Bu)(mu-H)IrCp* (4, 72% yield). Complexes 2 and 3a were characterized by X-ray crystallography. The addition of p-thiocresol yielded two products, 5a and 5b. The major product was found to be spectroscopically similar to the p-toluidine, p-cresol, tert-butyl alcohol, and acetone addition products, suggesting a similar formulation (Cp(2)Zr(SAr)(mu-N-t-Bu)(mu-H)IrCp*). Addition of H2S to 1 resulted in formation of the bridging sulfide complex Cp(2)Zr(mu L-N-t-Bu)(mu-S)IrCp* (6, 45% yield), presumably by a similar X-H addition followed by elimination of H-2. The addition of diethylphosphine and cyclohexylphosphine to imido complex 1 resulted in the unusual insertion of phosphide (PR(2)) into the Ir-N rather than the Ir-Zr bond to give Cp(2)Zr(mu-N(t-Bu)PEt(2))Ir(H)Cp* (8a, 63% yield) and Cp(2)Zr(mu-N(t-Bu)PHCy)Ir(H)Cp* (8b, 50% yield). An X-ray diffraction study was performed on 8a, which revealed that the Ir-Zr bond distance was 2.642(1) Angstrom, comparable to that in imido complex 1. The tert-butoxide complex 3b reacted with MeOTf to give CpZr(O-t-Bu)(OTf)(mu-H)(mu-N-t-Bu)IrCp* (11, 62% yield), a product resulting from the replacement of a single Zr-bonded Cp ligand with a triflate ligand. An X-ray diffraction study confirmed that the triflate ion was covalently bound to zirconium. The addition of trimethylphosphine to the tert-butoxide complex 3b resulted in reductive elimination of the imido and hydride bridges to give Cp(2)Zr(O-t-Bu)(NH-t-Bu) (12, 58% yield) and Cp*Ir(PMe(3))(2) (84% yield). The addition of H-2 to 1 resulted in the reversible addition of the H-H bond across the Ir-Zr bond to form Cp(2)Zr(H)(mu-N-t-Bu)(mu-H)IrCp* (9a, 69% yield). The terminal and bridging hydrides underwent exchange with each other and with excess H-2. Addition of MePhSiH(2) to 1 resulted in Cp(2)Zr(SiHMePh) (mu-N-t-Bu)(mu-H)IrCp* (10), a product analogous to that resulting from H-2 addition.