Synthesis of singly and doubly bridged ansa-zirconocene hydrides.: Formation of an unusual mixed valence trimeric hydride by reaction of H2 with {(Me2Si)2(η5-C5H3)2}Zr(CH3)2 and generation of a dinitrogen complex by reaction of N2 with a zirconocene dihydride

被引:75
作者
Chirik, PJ [1 ]
Henling, LM [1 ]
Bercaw, JE [1 ]
机构
[1] CALTECH, Arnold & Mabel Beckman Labs Chem Synthesis, Pasadena, CA 91125 USA
关键词
D O I
10.1021/om000739h
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
A series of singly and doubly bridged alzsa-zirconocene dihydride complexes has been prepared from hydrogenation of the corresponding dimethyl complexes. For the singly [SiMe2]-bridged species, the hydrogenation reaction is facile at 25 degreesC, whereas for the doubly [SiMe2]-bridged complexes hydrogenation occurs over the course of days at 87 degreesC, Hydrogenation of {meso-Me2Si(eta (5)-C5H3-3-CMe3)(2)}ZrMe2 affords the isomeric dimeric dihydrides [{meso-Me2Si(eta (5)-C5H3-3-CMe3)(2)}ZrH](2) (2)(mu (2)-H)(2), one of which has been characterized by X-ray diffraction, The raceme isomer of Me2Si(eta (5)-C5H2-2-SiMe3-4-CMe3)(2)ZrMe2 (BpZrMe(2)) reacts with dihydrogen, affording the first example of a monomeric ansa-zirconocene dihydride, {racMe(2)Si(eta (5)-C5H2-2-SiMe3-4-CMe3)(2)}ZrH2 (rac-BpZrH(2)). In the presence of dinitrogen, racBpZrH(2) undergoes thermal reductive elimination of Ha and reaction with N-2, yielding the dinitrogen complex BpZr(mu (2),eta (2)-eta (2)-N-2)ZrBp, for which the dinitrogen ligand is coordinated in a side-on fashion to both zirconiums with a N-N bond distance of 1.241(3) Angstrom. The doubly [SiMe2]-bridged zirconium dimethyl complex {(Me2Si)(2)(eta (5)-C5H3)(2)}ZrMe2 (RpZrMe(2)) undergoes hydrogenation under forcing conditions, affording the mixed valent (Zr(IV)/Zr(IV)/Zr(III)) hydride trimer [RpZr](3)(mu (3)-H)(2)(mu (2)-H)(3), which has been characterized by X-ray diffraction. More substituted doubly [SiMe2]-bridged zirconocene dihydrides such as [{(Me2Si)(2)(eta (5)-C5H-3,5(CHMe2)(2))(eta (5)-C5H2-4-CHMeEt}ZrH](2)-(mu (2)-H)(2) ([sec-BuThpZrH](2)(mu (2)-H)(2)) and [(Me2Si)(2)(eta (5)-C5H-2,4-(CHMe2)(2))(eta (5)-C5H2-4-CHMe2)ZrH](2) (mu (2)-H)(2) ([(i)PrThpZrH](2)(mu (2)-H)(2)) have been prepared and shown to be robust dimers in solution.
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页码:534 / 544
页数:11
相关论文
共 48 条
[1]   TABLES OF BOND LENGTHS DETERMINED BY X-RAY AND NEUTRON-DIFFRACTION .1. BOND LENGTHS IN ORGANIC-COMPOUNDS [J].
ALLEN, FH ;
KENNARD, O ;
WATSON, DG ;
BRAMMER, L ;
ORPEN, AG ;
TAYLOR, R .
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2, 1987, (12) :S1-S19
[2]   CRYSTAL AND MOLECULAR STRUCTURE OF AZOBISISOBUTYRONITRILE, C8H12N4 [J].
ARGAY, G ;
SASVARI, K .
ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL CRYSTALLOGRAPHY AND CRYSTAL CHEMISTRY, 1971, B 27 (OCT15) :1851-&
[3]   A HOMOGENEOUS IRON(II) SYSTEM CAPABLE OF SELECTIVELY CATALYZING THE REDUCTION OF TERMINAL ALKYNES TO ALKENES AND BUTA-1,3-DIENES [J].
BIANCHINI, C ;
MELI, A ;
PERUZZINI, M ;
VIZZA, F ;
ZANOBINI, F ;
FREDIANI, P .
ORGANOMETALLICS, 1989, 8 (08) :2080-2082
[4]   STRUCTURAL STUDIES OF THE SYSTEM TRANS-AZOBENZENE TRANS-STILBENE .1. A REINVESTIGATION OF THE DISORDER IN THE CRYSTAL-STRUCTURE OF TRANS-AZOBENZENE, C12H10N2 [J].
BOUWSTRA, JA ;
SCHOUTEN, A ;
KROON, J .
ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, 1983, 39 (AUG) :1121-1123
[5]   STEREOSPECIFIC OLEFIN POLYMERIZATION WITH CHIRAL METALLOCENE CATALYSTS [J].
BRINTZINGER, HH ;
FISCHER, D ;
MULHAUPT, R ;
RIEGER, B ;
WAYMOUTH, RM .
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 1995, 34 (11) :1143-1170
[6]   Asymmetric hydrogenation of unfunctionalized trisubstituted olefins with a chiral titanocene catalyst (vol 115, pg 12569, 1993) [J].
Broene, RD ;
Buchwald, SL .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (39) :9458-9458
[7]  
BRUKER, 1999, SMART SAINT SHELXTL
[8]  
BULLS AR, 1988, THESIS CALIFORNIA I
[9]  
BURGER BJ, 1987, ACS SYM SER, V357, pCH4
[10]   DOUBLE-DIMETHYLSILYL-BRIDGED DICYCLOPENTADIENYL GROUP-4 METAL-COMPLEXES - X-RAY MOLECULAR-STRUCTURES OF M[(ME2SI)2(ETA-5-C5H3)2]CL2 (M=TI, ZR) AND (TICL3)2(MU-[(ME2SI)2(ETA-5-C5H3)2]) [J].
CANO, A ;
CUENCA, T ;
GOMEZSAL, P ;
ROYO, B ;
ROYO, P .
ORGANOMETALLICS, 1994, 13 (05) :1688-1694