Four-coordinate disilyl cobalt(Ⅱ)complexes with NHC ligation:Synthesis,characterization,and reactivity

Lan Zhou ¹Dongyang Wang ²Chengbo Yang ²Liang Deng³

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作者信息

1. College of Chemistry and Materials Science,University of Science and Technology of China,Hefei 230026,China;State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032,China
2. State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032,China
3. State Key Laboratory of Organometallic Chemistry,Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences,Shanghai 200032,China;School of Chemistry and Materials Science,Hangzhou Institute for Advanced Study,University of Chinese Academy of Sciences,Hangzhou 310024,China
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Abstract

Silyl cobalt species are putative intermediates in cobalt-catalyzed transformations of hydrosilanes.However,their reactivity has remained poorly understood.Reported here is the investigation on four-coordinate disilyl Co(Ⅱ)complexes with N-hetereocyclic carbene ligation.The reactions of[(ICy)2Co(vtms)](ICy=1,3-dicyclohexylimidazol-2-ylidene,vtms=vinyltrimethylsilane)with pri-mary and secondary hydrosilanes(3 equiv.)furnish the four-coordinate disilyl complexes[trans-(ICy)2Co(SiHRR')2](SiHRR'=SiH2Mes,1;SiH2Ph,2;SiH2Cy,3;SiHPh2,4;SiHEt2,5)in moderate to good yields.The structures of 1,2 and 4 were established by single-crystal X-ray diffraction.Solution mag-netic susceptibility measurement and EPR spectroscopy indicate their low-spin nature(S=1/2).Reactiv-ity studies on 4 led to the establishment of the conversions of 4 to the disilyl dihydride Co(Ⅲ)complex[K(THF)][(ICy)2Co(H)2(SiHPh2)2]n(6)and the fluorosilyl Co(Ⅱ)complex[(ICy)2Co(THF)(SiFPh2)][BF4](7)when 4 was treated with excess amount of K and AgBF4,respectively,in THF.These conversions hint at the high activity of low-valent and high-valent disilyl cobalt species[trans-(ICy)2Co(SiHPh2)2]1-and[trans-(ICy)2Co(SiHPh2)2]2+.Complex 4 is reactive toward terminal alkynes,but inert toward alkenes and internal alkynes.The reactions of 4 with terminal alkynes CyC=CH and Me3SiC=CH(3 equiv.)yield the Co(Ⅱ)complexes[(ICy)2Co(C≡CCy)2](8)and[(ICy)2Co(C=CSiMe3)((SiMe3)C=CH2)](9),respectively,along with H2SiPh2 and alkynylsilanes RC=CSiHPh2(R=Cy,SiMe3),whereas the reaction with 4-CF3C6H4C≡CH(3 equiv.)produce[(ICy)2Co(C=CAr)((Ar)C=CH(SiHPh2)C=CHAr)](Ar=4-CF3C6H4)(10)and H2SiPh2.These reactions are proposed to involve σ-bond metathesis reactions between alkyne C(sp)-H bonds and Co-Si bonds in 4.Complexes 6-10 have been characterized by NMR spectroscopy,X-ray diffraction study,and elemental analysis.

Key words

Disilyl/Cobalt/N-Heterocyclic carbene/Four-coordinate

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基金项目

国家重点研发计划(2021YFA1500203)

国家自然科学基金(22231010)

国家自然科学基金(22061160464)

国家自然科学基金(21821002)

国家自然科学基金(22201290)

Shanghai Sailing Program(22YF1458200)

出版年

2024

中国化学快报(英文版)

中国化学会

中国化学快报(英文版)

CSTPCD

影响因子：0.771

ISSN：1001-8417

参考文献量36

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