Activation of arene C-H bonds by a cationic hafnium silyl complex possessing an α-agostic Si-H interaction

被引：32

作者：

Sadow, AD ^{[1
]}

Tilley, TD ^{[1
]}

机构：

[1] Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA

来源：

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY | 2002年 / 124卷 / 24期

关键词：

D O I：

10.1021/ja025940t

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

The reaction of Cp2Hf(SiMes2H)Me (1) with B(C6F5)3 produces zwitterionic Cp2Hf(n2-SiHMes2)(μ-Me)B(C6F5)3 (2), which is stable for >8 h at -40 °C in toluene-d8. Spectroscopic data provide evidence for an unusual a-agostic Si-H interaction in 2. At room temperature, 2 reacts with the C-H bonds of aromatic hydrocarbons such as benzene and toluene to produce Cp2Hf(Ph)(μ-Me)B(C6F5)3 (3), isomers of Cp2Hf(C6H4Me)(μ-Me)B(C6F5)3 (4-6), and Cp2Hf(CH2Ph)(μ-Me)B(C6F5)3 (7), respectively. The reaction involving benzene is first-order in both 2 and benzene; rate = k[2][C6H6]. Mechanistic data including activation parameters (ΔH = 19(1) kcal/mol; ΔS = -17(3) eu), a large primary isotope effect of 6.9(7), and the experimentally determined rate law are consistent with a mechanism involving a concerted transition state for C-H bond activation. Copyright © 2002 American Chemical Society.

引用

页码：6814 / 6815

页数：2

共 38 条

[1] CARBON HYDROGEN AND CARBON CARBON BOND ACTIVATION WITH HIGHLY ELECTROPHILIC TRANSITION-METAL COMPLEXES [J].

BERCAW, JE .

PURE AND APPLIED CHEMISTRY, 1990, 62 (06) :1151-1154

[2] FACILE ARENE C-H BOND ACTIVATION BY TANTALUM SILYL COMPLEXES [J].

BERRY, DH ;

JIANG, Q .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1989, 111 (20) :8049-8051

[3] C-H ACTIVATION MECHANISMS AND REGIOSELECTIVITY IN THE CYCLOMETALATION REACTIONS OF BIS(PENTAMETHYLCYCLOPENTADIENYL)THORIUM DIALKYL COMPLEXES [J].

BRUNO, JW ;

SMITH, GM ;

MARKS, TJ ;

FAIR, CK ;

SCHULTZ, AJ ;

WILLIAMS, JM .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1986, 108 (01) :40-56

[4] RELATIVE BOND-DISSOCIATION ENERGIES FOR EARLY TRANSITION-METAL ALKYL, ARYL, ALKYNYL AND HYDRIDE COMPOUNDS - EQUILIBRATION OF METALLATED CYCLOPENTADIENYL DERIVATIVES OF PERALKYLATED HAFNOCENE AND SCANDOCENE WITH HYDROCARBONS AND DIHYDROGEN [J].

BULLS, AR ;

BERCAW, JE ;

MANRIQUEZ, JM ;

THOMPSON, ME .

POLYHEDRON, 1988, 7 (16-17) :1409-1428

[5] OLEFIN INSERTION IN A METAL ALKYL IN A ZIEGLER POLYMERIZATION SYSTEM [J].

CLAWSON, L ;

SOTO, J ;

BUCHWALD, SL ;

STEIGERWALD, ML ;

GRUBBS, RH .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1985, 107 (11) :3377-3378

[6]

COTTER DW, 1991, J ORGANOMET CHEM, V417, pC1

[7]

DAVIS JA, 1990, SELECTIVE HYDROCARBO

[8] Highly electrophilic olefin polymerization catalysts. Quantitative reaction coordinates for fluoroarylborane/alumoxane methide abstraction and ion-pair reorganization in group 4 metallocene and "constrained geometry" catalysts [J].

Deck, PA ;

Beswick, CL ;

Marks, TJ .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1998, 120 (08) :1772-1784

[9] Unusual ''cation-like'' zirconocene hydrosilyl complex. Silylium ligand or a nonclassically bonded Si-H? [J].

Dioumaev, VK ;

Harrod, JF .

ORGANOMETALLICS, 1996, 15 (18) :3859-3867

[10] SYNTHESIS AND PROPERTIES OF BIS(PENTAMETHYLCYCLOPENTADIENYL) ACTINIDE HYDROCARBYLS AND HYDRIDES - A NEW CLASS OF HIGHLY REACTIVE F-ELEMENT ORGANO-METALLIC COMPOUNDS [J].

FAGAN, PJ ;

MANRIQUEZ, JM ;

MAATTA, EA ;

SEYAM, AM ;

MARKS, TJ .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1981, 103 (22) :6650-6667

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