Substituent Effects in the Hydrosilylation of Coordinated Dinitrogen in a Ditantalum Complex: Cleavage and Functionalization of N2
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- 作者：Bruce A. MacKay ; Rui F. Munha ; and Michael D. Fryzuk
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：July 26, 2006
- 年：2006
- 卷：128
- 期：29
- 页码：9472 - 9483
- 全文大小：441K
- 年卷期：v.128,no.29(July 26, 2006)
- ISSN：1520-5126
文摘
The dinitrogen complex ([NPN]Ta)2(
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1:2-N2)(-H)2, 1, (where [NPN] = (PhNSiMe2CH2)2PPh)undergoes hydrosilylation with primary and secondary alkyl- and arylsilanes, giving a new N-Si bond anda new terminal tantalum hydride derived from one Si-H unit. Various primary silanes can be employed togive isolable complexes of the general formula ([NPN]TaH)(-N-N-SiHnR3-n)(-H)2(Ta[NPN]) (5, R=Bu,n = 2; 9, R=Ph, n = 2). Analogous complexes featuring secondary silanes are not isolable, becausethese products, and 5 and 9, are uniformly unstable toward reductive elimination of bridging hydrides asH2, followed by cleavage of the N-N bond to give ([NPN]TaH)(-N)(-N-SiHnR3-n)(Ta[NPN]) (6, R=Bu,n = 2; 10, R=Ph, n = 2; 15, R=Ph, n = 1; 16, R=Ph and Me, n = 1). The bridging nitrido ligand in thesecomplexes is itself a substrate for a second hydrosilylation when n = 2, and schemes leading to Ta(IV)complexes of the general formula ([NPN]Ta)2(-N-SiH2R)(-N-SiH2R') via elimination of H2 are reported(4, R=R' = Bu; 12, R=Bu, R' = Ph; 13, R=Bu, R' = CH2CH2SiH3). At this point, the general reactionmanifold for these compounds ramifies, with distinct outcomes occurring for different R groups-[NPN]ligand amide migration from Ta to RSi affords 11, ([NPN]Ta(-NS iH2Ph)(-NSiH2Ph)Ta[NPN]), whereasstable complex 6 rearranges to give 7, ([NP(C6H4)N]Ta(BuSiH2N--SiHBu--N)T a[NPN]) in the presence of excess silane. Ethanediylbissilane reacts with 1 to give 14, ([NP(C6H4)N]Ta(N-SiH2CH2CH2Si(H)--N)T a[NPN]), isostructural to 7.
-1:2-N2)(-H)2, 1, (where [NPN] = (PhNSiMe2CH2)2PPh)undergoes hydrosilylation with primary and secondary alkyl- and arylsilanes, giving a new N-Si bond anda new terminal tantalum hydride derived from one Si-H unit. Various primary silanes can be employed togive isolable complexes of the general formula ([NPN]TaH)(-N-N-SiHnR3-n)(-H)2(Ta[NPN]) (5, R=Bu,n = 2; 9, R=Ph, n = 2). Analogous complexes featuring secondary silanes are not isolable, becausethese products, and 5 and 9, are uniformly unstable toward reductive elimination of bridging hydrides asH2, followed by cleavage of the N-N bond to give ([NPN]TaH)(-N)(-N-SiHnR3-n)(Ta[NPN]) (6, R=Bu,n = 2; 10, R=Ph, n = 2; 15, R=Ph, n = 1; 16, R=Ph and Me, n = 1). The bridging nitrido ligand in thesecomplexes is itself a substrate for a second hydrosilylation when n = 2, and schemes leading to Ta(IV)complexes of the general formula ([NPN]Ta)2(-N-SiH2R)(-N-SiH2R') via elimination of H2 are reported(4, R=R' = Bu; 12, R=Bu, R' = Ph; 13, R=Bu, R' = CH2CH2SiH3). At this point, the general reactionmanifold for these compounds ramifies, with distinct outcomes occurring for different R groups-[NPN]ligand amide migration from Ta to RSi affords 11, -NS-NSiH2Ph)Ta[NPN]),-SiHBu--N)T-N)T