Molecular structure and vinyl chloride insertion of a cationic zirconium (IV) acyl carbonyl complex

Article abstract of DOI:10.1021/om0210311

The reaction of vinyl chloride (VC) with the cationic Zr acyl complex [Cp₂Zr{C(=O)Me}-(CO)][MeB(C₆F₅)₃] (1a/b, O-inside and O-outside isomers) yields an unusual dinuclear dicationic μ-acyl μ-keto-alkoxide complex, [Cp₂Zr{μ-C(=O)Me}{μ-OCMe (CH=CH₂)C(=O)-Me}ZrCp₂][MeB(C₆ F₅)₃]₂ (3), which was characterized by NMR spectroscopy and X-ray crystallography. This reaction proceeds by 1,2 insertion into the Zr-acyl bond of Cp₂Zr-{C(=O)Me}⁺ to yield Cp₂Zr{CH₂CHClC(=O)Me}⁺, which undergoes β-Cl elimination to form methyl vinyl ketone (MVK) and Cp₂ZrCl⁺ (8). The MVK is trapped by Cp₂Zr{C(=O)Me}⁺ to form [Cp₂Zr{η²-C(=O)Me}(MVK)][MeB(C₆ F₅)₃] (9), which rearranges to [Cp₂Zr{k²-OC(Me)-(CH=CH₂)C(=O)Me}][MeB (C₆F₅)₃] (10). Intermediate 10 is trapped by Cp₂Zr{C(=O)Me}⁺ to form 3.3 is also formed by the reaction of 1a/b with 0.5 equiv of MVK. 1,2 VC insertion of Cp₂Zr{C(=O)Me}⁺ is favored over 2,1 insertion by steric factors. The molecular structure of 1a was determined by X-ray crystallography.

Full text of DOI:10.1021/om0210311

2080
Organometallics 2003, 22, 2080-2086
Molecu la r Str u ctu r e a n d Vin yl Ch lor id e In ser tion of a
Ca tion ic Zir con iu m (IV) Acyl Ca r bon yl Com p lex
Han Shen and Richard F. J ordan*
Department of Chemistry, The University of Chicago, 5735 South Ellis Avenue,
Chicago, Illinois 60637
Received December 20, 2002
The reaction of vinyl chloride (VC) with the cationic Zr acyl complex [Cp2Zr{C(dO)Me}-
(CO)][MeB(C6F5)3] (1a /b, O-inside and O-outside isomers) yields an unusual dinuclear
dicationic µ-acyl µ-keto-alkoxide complex, [Cp2Zr{µ-C(dO)Me}{µ-OCMe(CHdCH2)C(dO)-
Me}ZrCp2][MeB(C6F5)3]2 (3), which was characterized by NMR spectroscopy and X-ray
crystallography. This reaction proceeds by 1,2 insertion into the Zr-acyl bond of Cp2Zr-
{C(dO)Me}+ to yield Cp2Zr{CH2CHClC(dO)Me}+, which undergoes â-Cl elimination to form
methyl vinyl ketone (MVK) and Cp2ZrCl+ (8). The MVK is trapped by Cp2Zr{C(dO)Me}+ to
form [Cp2Zr{η2-C(dO)Me}(MVK)][MeB(C6F5)3] (9), which rearranges to [Cp2Zr{κ2-OC(Me)-
(CHdCH2)C(dO)Me}][MeB(C6F5)3] (10). Intermediate 10 is trapped by Cp2Zr{C(dO)Me}+
to form 3. 3 is also formed by the reaction of 1a /b with 0.5 equiv of MVK. 1,2 VC insertion
of Cp2Zr{C(dO)Me}+ is favored over 2,1 insertion by steric factors. The molecular structure
of 1a was determined by X-ray crystallography.
In tr od u ction
insertion to yield O-chelated L2Pd{CHClCH2C(dO)Me}+
products which cannot â-Cl eliminate because they do
not have a â-Cl substituent.4 However, the chelated
species do not react further with CO, VC, or ethylene
due to the robustness of the chelate rings and the low
migratory aptitude of the R-Cl-substituted -CHClCH2C-
(dO)Me group. We hypothesized that analogous but
more reactive LnM{CHClCH2C(dO)R}+ species might
form by 2,1 VC insertion into other LnM{C(dO)R}+
catalysts. To study this possibility, we investigated the
reaction of VC with Cp2Zr{η2-C(dO)Me}+, which is
known to insert alkynes and alkenes.5-7 In fact, we have
found that this species undergoes 1,2 VC insertion,
which ultimately leads to an unusual dinuclear product.
During the course of this work we also determined the
molecular structure of the Zr(IV) carbonyl complex [Cp2-
Zr{η2-C(dO)Me}(CO)][MeB(C6F5)3] (O-inside isomer).
The synthesis of new materials by insertion polym-
erization/copolymerization of vinyl chloride (VC) using
metal catalysts is an attractive goal because this ap-
proach may enable better control of polymer structure
and properties than is possible by conventional radical
methods.1 We showed previously that (C5R5)2ZrR+, (C5-
Me4SiMe2NtBu)TiR+, (Me2bipy)PdR+, {ArNdC(Me)C-
(Me)dNAr}PdMe+ (Ar ) 2,6-iPr2-C6H3), and (salicyla-
ldiminato)Ni(Ph)(PPh3) complexes readily insert VC to
yield LnMCH2CHClR+ intermediates, which undergo
â-Cl elimination to produce M-Cl species and the
corresponding CH2dCHR olefin.2 The â-Cl elimination
reaction precludes homopolymerization of VC or copo-
lymerization of VC with other olefins by these catalysts.
Analogous 1,2 insertion/â-X elimination reactions of
CH2dCHX substrates with (tBu3SiO)3TaH2, Cp2ZrHCl,
{2,6-(o-tol-NdCMe)2pyridine}FeCl2/MAO, and {ArNd
C(Me)C(Me)dNAr}PdMe+ have also been reported.3
In an effort to circumvent â-Cl elimination, we
investigated the reactions of L2Pd{C(dO)Me}+ acyl
complexes with VC. These reactions proceed by 2,1 VC
Resu lts a n d Discu ssion
Gen er a tion of [Cp 2Zr {η2-C(dO)Me}(CO)][MeB-
(C6F 5)3] (1a /b). We showed previously that the Zr(IV)
acyl carbonyl complex [Cp2Zr{η2-C(dO)Me}(CO)][MeB-
(C6F5)3] is generated as a mixture of “O-inside” and “O-
outside” isomers (1a /1b ) 5:1 at 23 °C) in quantitative
yield by the reaction of Cp2ZrMe(µ-Me)B(C6F5)3 with CO
(3 atm) in CD2Cl2 (eq 1).6 The analogous Cp*2Zr{η2-C(d
O)Me}(CO)+ cation (Cp* ) C5Me5) is generated in a
(1) (a) Vinyl Chloride and Poly (Vinyl Chloride). Kirk-Othmer
Encyclopedia of Chemical Technology, 3rd ed.; Wiley & Sons: New
York, 1983; Vol. 23, pp 865-936. (b) Kirk-Othmer Encyclopedia of
Chemical Technology Home Page. http://www.mrw.interscience.wil-
ey.com/kirk/ (accessed J uly 2002).
(2) (a) Stockland, R. A., J r.; J ordan, R. F. J . Am. Chem. Soc. 2000,
122, 6315. (b) J ordan, R. F.; Stockland, R. A., J r.; Shen, H.; Foley, S.
Polym. Mater. Sci. Eng. 2002, 87, 39. (c) J ordan, R. F. Polym. Prepr.
(Am. Chem. Soc., Div. Polym. Chem.) 2001, 42, 829. (d) Stockland, R.
A., J r.; Foley, S. R.; J ordan, R. F. J . Am. Chem. Soc. 2003, 125, 796.
(e) Foley, S. R.; Stockland, R. A., J r.; Shen, H.; J ordan, R. F. J . Am.
Chem. Soc. 2003, ASAP.
(3) (a) Strazisar, S. A.; Wolczanski, P. T. J . Am. Chem. Soc. 2001,
123, 4728. (b) Watson, L. A.; Yandulov, D. V.; Caulton, K. G. J . Am.
Chem. Soc., 2001, 123, 603. (c) Boone, H.; Athey, P. S.; Mullins, M. J .;
Philipp, D.; Muller, R.; Goddard, W. A. J . Am. Chem. Soc. 2002, 124,
8790. (d) Kang, M.; Sen, A.; Zakharov, L.; Rheingold, A. L. J . Am.
Chem. Soc. 2002, 124, 12080.
(4) L2 ) 4,4′-Me2-2,2′-bipyridine (Me2bipy), 4,4′-tBu2-2,2′-bipyridine
(tBu2bipy), 1,3-bis(diphenylphosphino)propane (dppp), 1,2-bis(dimeth-
ylphosphino)ethane (dmpe)). Shen, H.; J ordan, R. F. Organometallics
2003, in press.
(5) Shen, H.; J ordan, R. F. Abstr. Pap. Am. Chem. Soc. 2002, 224,
640-INOR.
(6) (a) Guo, Z.; Swenson, D. C.; Guram, A. S.; J ordan, R. F.
Organometallics 1994, 13, 766. (b) Guram, A. S.; Guo, Z.; J ordan, R.
F. J . Am. Chem. Soc. 1993, 115, 4902.
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Chem. Soc. 2000, 122, 5226.
10.1021/om0210311 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 03/27/2003

Cationic Zirconium(IV) Acyl Carbonyl Complex
Organometallics, Vol. 22, No. 10, 2003 2081
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 1a
Zr(1)-C(11)
Zr(1)-O(2)
C(12)-O(2)
Zr(1)-C100a
2.366(4)
2.251(3)
1.240(5)
2.184
Zr(1)-C(12)
C(12)-C(13)
C(11)-O(1)
Zr(1)-C200a
2.184(4)
1.490(6)
1.117(5)
2.190
C(11)-Zr(1)-C100
C(12)-Zr(1)-C100
O(2)-Zr(1)-C100
C100-Zr(1)-C200
Zr(1)-C(12)-O(2)
O(2)-C(12)-C(13)
97.7
111.2
116.2
133.4
C(11)-Zr(1)-C200
C(12)-Zr(1)-C200
O(2)-Zr(1)-C200
Zr(1)-C(11)-O(1)
98.9
106.0
113.7
175.6(4)
76.8(3) Zr(1)-C(12)-C(13) 159.7(3)
123.6(4) O(2)-Zr(1)-C(12)
32.4(1)
79.5(1)
C(11)-Zr(1)-C(12) 111.9(2) C(11)-Zr(1)-O(2)
a
C100 is the centroid of the C(1)-C(5) Cp ring; C200 is the
centroid of the C(6)-C(10) Cp ring.
are essentially coplanar. The η2-acyl group is structur-
ally similar to that in 2b. The Zr-O distance and Zr-
C-O angle in 1a (Zr(1)-O(2) 2.251(3) Å, Zr(1)-C(12)-
O(2) ) 76.8(3)°) are nearly identical to the corresponding
values in 2b (2.242(7) Å, 74.7(6)°), but the Zr-C distance
in 1a (Zr(1)-C(12) ) 2.184(4) Å) is slightly shorter than
that in 2b (2.22(1) Å). The Zr-Cacyl and Zr-O distances
in 1a are slightly shorter than the corresponding
distances in the neutral analogue Cp2Zr{C(dO)Me}Me
(O-inside isomer; Zr-Cacyl ) 2.197(6) Å, Zr-O ) 2.290-
(4) Å), consistent with the highly electrophilic character
of the cationic Zr(IV) center.12 Interestingly, the Zr-
CO bond (Zr(1)-C(11) ) 2.366(4) Å) in 1a is ca. 0.11 Å
longer than that in 2b (2.25(1) Å). This difference and
the difference in Zr-Cacyl distances noted above reflect
the presence of σZr-C(acyl)-π*CO back-bonding in the
latter species. The Zr-CO distances in 1a and 2b are
far longer than those in Zr(II) carbonyl complexes, e.g.,
Cp2Zr(CO)2 (2.187(4) Å),13 Cp*2Zr(CO)2 (2.145(9) Å),14
which possess strong d-π* back-bonding. These struc-
tural results support the bonding analysis for (C5R5)2-
Zr{C(dO)Me}(CO)+ species developed previously based
on IR and computational results.6
F igu r e 1. ORTEP view of the cation of 1a . Hydrogen
atoms are omitted.
similar fashion and favors the “O-outside” form (2a /2b
) 1:9); 2b was characterized by X-ray diffraction. These
species are rare examples of d0 metal carbonyl com-
plexes.8 The νCO values for the O-inside isomers 1a
(2176 cm-1) and 2a (2152 cm-1) are higher than the free
CO value (2143 cm-1), reflecting the absence of d-π*
back-bonding. However the νCO values for the O-outside
isomers 1b (2123 cm-1) and 2b (2105 cm-1) are slightly
lower than the free CO value, due to nonclassical back-
bonding from a filled Zr-acyl σ orbital to a CO π*
orbital.6 Complex 1a /b undergoes irreversible loss of CO
if the CO pressure is reduced to ca. 1 atm, leading to
the precipitation of the insoluble compound Cp2Zr{η2-
C(dO)Me}(µ-Me)B(C6F5)3.
Rea ction of VC w ith Cp 2Zr {η2-C(dO)Me}+. The
reaction of 1a /b with VC was performed by freezing a
CD2Cl2 solution of 1a /b at -196 °C, removing the
gaseous CO under vacuum, adding VC (ca. 14 equiv) at
(10) (a) Ryan, E. J . Bis(cyclopentadienyl)zirconium and -hafnium
Halide Complexes in Oxidation State +4. In Comprehensive Organo-
metallic Chemistry II: A Review of the Literature 1982-1994; Abel, E.
W., Stone, F. G. A., Wilkinson, G., Lappert, M. F., Eds.; Elsevier
Science Inc.: New York, 1995; Vol. 4, pp 483-499. (b) Cardin, D. J .;
Lappert, M. F.; Raston, C. L. Chemistry of Organo-Zirconium and
-Hafnium Compounds; Ellis Horwood: Chichester, 1986.
(11) (a) Guzei, I. A.; Stockland, R. A., J r.; J ordan, R. F. Acta
Crystallogr. 2000, C56, 635. (b) Liu, F.-C.; Liu, J .; Meyers, E. A.; Shore,
S. G. Inorg. Chem. 1999, 38, 2169. (c) Clegg, W.; Horsburgh, L.;
Lindsay, D. M.; Mulvey, R. E. Acta Crystallogr. 1998, C54, 315 (d)
Lappert, M. F.; Raston, C. L.; Skelton, B. W.; White, A. H. J . Chem.
Soc., Dalton Trans. 1997, 2895. (e) Erker, G.; Fro¨mberg, W.; Benn, R.;
Mynott, R.; Angermund, K.; Kru¨ger Organometallics 1989, 8, 911. (f)
Bailey, S. I.; Colgan, D.; Engelhardt, L. M.; Leung, W.-P.; Papasergio,
R. I.; Raston, C. L.; White, A. H. J . Chem. Soc., Dalton Trans. 1986,
603. (g) Erker, G.; Czisch, P.; Mynott, R.; Tsay, Y.-H.; Kru¨ger, C.
Organometallics 1985, 4, 1310. (h) Hunter, W. E.; Hrncir, D. C.;
Bynum, R. V.; Penttila, R. A.; Atwood, J . L. Organometallics 1983, 2,
750. (i) Atwood, J . L.; Barker, G. K.; Holton, J .; Hunter, W. E.; Lappert,
M. F.; Pearce, R. J . Am. Chem. Soc. 1977, 99, 6645.
(12) Guram, A. S.; J ordan, R. F. Cationic Organozirconium and
Organohafnium Complexes. In Comprehensive Organometallic Chem-
istry II: A Review of the Literature 1982-1994; Abel, E. W., Stone, F.
G. A., Wilkinson, G., Lappert, M. F., Eds.; Elsevier Science Inc.: New
York, 1995; Vol. 4, pp 589-625.
(13) Atwood, J . L.; Rogers, R. D.; Hunter, W. E.; Floriani, C.;
Fachinetti, G.; Chiesi-Villa, A. Inorg. Chem. 1980, 19, 3812.
(14) Sikora, D. J .; Rausch, M. D.; Rogers, R. D.; Atwood, J . L. J .
Am. Chem. Soc. 1981, 103, 1265.
X-r a y Str u ctu r e of 1a . Isomer 1a selectively crystal-
lizes from a CH2Cl2 solution of 1a /b at -80 °C and was
characterized by X-ray diffraction. The solid state
structure of 1a consists of discrete Cp2Zr{η2-C(dO)Me}-
(CO)+ and MeB(C6F5)3- ions. The closest cation-anion
contact is between a Cp hydrogen and a meta-fluorine
(H(3)- - -F(2) ) 2.491 Å) and is somewhat shorter than
the sum of the van der Waals radii (ca. 2.67 Å).9 An
ORTEP view of the Cp2Zr{η2-C(dO)Me}(CO)+ cation of
1a is shown in Figure 1, and selected bond distances
and bond angles are given in Table 1.
The Cp2Zr{η2-C(dO)Me}(CO)+ cation adopts a bent
metallocene structure with centroid-Zr-centroid angles
and Zr-centroid distances in the range observed for
other Cp2Zr complexes.10,11 The η2-acyl and CO ligands
are located in the plane between the two Cp ligands,
and the Zr(1), O(1), O(2), C(11), C(12), and C(13) atoms
(8) Lupinetti, A. J .; Strauss, S. H.; Frenking, G. Prog. Inorg. Chem.
2001, 49, 1.
(9) van der Waals radii (H: 1.20 Å; F: 1.47 Å) taken from Bondi,
A. J . Phys. Chem. 1964, 68, 441.

2082 Organometallics, Vol. 22, No. 10, 2003
Shen and J ordan
-196 °C, and warming to 23 °C. Under these conditions
a yellow crystalline solid starts to form within 1 h, and
the reaction is complete after 12 h (eq 2). NMR analysis
of the solid in THF-d8 shows that it is a mixture of a
dinuclear dicationic complex [Cp2Zr{µ-C(dO)Me}{µ-
OCMe(CHdCH2)C(dO)Me}ZrCp2][MeB(C6F5)3]2 (3, 79%
vs 1a /b), formed by reaction of 1a /b with VC, and Cp2-
Zr{η2-C(dO)Me}(µ-Me)B(C6F5)3 (2% vs 1a /b), formed by
loss of CO from 1a /b and precipitation as described
above.15 The structure of 3 was established by X-ray
1
diffraction, H NMR spectroscopy, and alternate syn-
thesis (vide infra). NMR analysis of the filtrate shows
that Cp2ZrCl2, other unidentified Cp2Zr species, and
B(C6F5)3 are present.
Alter n a te Syn th esis of 3. The reaction of 1a /b with
0.5 equiv of methyl vinyl ketone (MVK) in CD2Cl2 at
23 °C also affords 3 as a yellow crystalline solid in high
yield (91%, eq 3). In contrast to the 3 produced in eq 2,
the product of eq 3 is not contaminated by Cp2Zr{η2-
C(dO)Me}(µ-Me)B(C6F5)3.
F igu r e 2. ORTEP views of the dication of 3. Hydrogen
atoms are omitted.
Molecu la r Str u ctu r e of 3. Single crystals of 3 were
isolated from the reactions of 1a /b with VC (eq 2) and
with MVK (eq 3) and were analyzed by X-ray diffraction.
The two analyses are essentially identical, and only the
latter is described here. 3 crystallizes as discrete cations
and anions; there are no close cation-anion contacts.
ORTEP views of the dinuclear dication of 3 are shown
in Figure 2, and corresponding space-filling diagrams
are shown in Figure 3. Selected bond distances and bond
angles are listed in Table 2.
The dinuclear dication of 3 can be viewed as an adduct
of two fragments: the η2-acyl cation Cp2Zr{η2-C(dO)-
Me}+ and the O-chelated keto-alkoxide cation Cp2Zr-
{κ2-OCMe(CHdCH2)C(dO)Me}+, which are bridged
through O(1) and O(2). The ring formed by Zr(1), O(1),
Zr(2), and O(2) is slightly puckered as O(2) deviates from
the Zr(1)-Zr(2)-O(1) plane by 0.121 Å. Space-filling
diagrams (Figure 3) show that the two fragments fit
together snugly, which may explain why the formation
of 3 is favored.
The structure of the Cp2Zr{η2-C(dO)Me}+ unit in 3
is very similar to that in 1a except that the Zr(2)-O(1)
distance (2.290(3) Å) is ca. 0.04 Å longer than the
corresponding distance in 1a , due to coordination of the
second Zr center (Zr(1)) to the acyl oxygen. In fact, the
Zr(1)-O(1) distance (2.181(3) Å) is in the range observed
F igu r e 3. Space-filling diagrams of the dication of 3.
for Zr(IV) ketone complexes such as Cl4Zr{OdC(Me)tBu}2
(2.192(2) Å)16 and [C5Me4{CH2B(C6F5)3}]Cp*Zr(Ph)(Od
CMe2) (2.132(5) Å).17 The keto-alkoxide ligand binds to
(15) Attempts to avoid the formation of Cp2Zr{η2-C(dO)Me}(µ-Me)B-
(C6F5)3 by increasing the CO pressure were unsuccessful, because high
CO pressure (>1 atm) inhibits VC uptake.

Cationic Zirconium(IV) Acyl Carbonyl Complex
Organometallics, Vol. 22, No. 10, 2003 2083
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3
mixture of 4 and 5. The NMR data for 4 agree with those
-
of the corresponding BPh4 salt, which we prepared
previously.6b The resonances for the coordinated THF
C(1)-O(1)
C(1)-Zr(2)
C(3)-C(5)
1.252(5)
2.195(4)
1.507(6)
1.539(7)
1.239(5)
2.181(3)
2.271(3)
2.239(3)
2.217
C(1)-C(2)
1.463(5)
1.443(4)
1.512(6)
1.365(8)
1.487(5)
2.290(3)
2.296(3)
2.219
C(3)-O(2)
C(3)-C(7)
(δ 4.18 (m), 2.14 (m)) are shifted from those of free THF
1
in CD2Cl2 (δ 3.68 (m), 1.82 (m)). The H NMR spectrum
C(3)-C(4)
C(5)-C(6)
C(7)-C(8)
O(1)-Zr(2)
O(2)-Zr(2)
Zr(1)-C(100)a
Zr(2)-C(300)a
of 5 contains resonances for coordinated THF (δ 4.18
(m), 2.14 (m)) and the pendant vinyl group (δ 5.99 (dd,
J ) 17, 11), 5.44 (dd, J ) 17, 1), and 5.39 (dd, J ) 11,
1)). Two Cp resonances are expected for 5, but only one
is observed in the 1H NMR spectrum (δ 6.23). However,
the Cp and Zr-THF 13C NMR resonances of 5 are broad.
These observations suggest that 5 undergoes the ex-
change shown in eq 5, probably via chelate ring opening,
THF exchange with site epimerization at Zr, and chelate
ring closing. The coordination of the carbonyl oxygen
to Zr of 5 is established by the low-field carbonyl 13C
NMR resonance at δ 230.6, which shifted downfield from
the free ketone region (δ 206-218).25 In addition, the
IR spectrum of 5 displays a carbonyl absorption at νCO
) 1505 cm-1, which is typical of a ketone unit coordi-
nated to a Lewis acid.24
C(7)-O(3)
O(1)-Zr(1)
O(2)-Zr(1)
O(3)-Zr(1)
Zr(1)-C(200)a
Zr(3)-C(400)a
2.216
2.196
O(1)-C(1)-C(2)
C(2)-C(1)-Zr(2)
O(2)-C(3)-C(7)
O(2)-C(3)-C(4)
C(7)-C(3)-C(4)
O(3)-C(7)-C(8)
C(8)-C(7)-C(3)
C(1)-O(1)-Zr(2)
C(3)-O(2)-Zr(1)
Zr(1)-O(2)-Zr(2)
C300-Zr(2)-C400
119.6(4)
162.3(3)
106.4(3)
111.0(4)
108.6(4)
118.9(4)
121.5(3)
69.7(2)
O(1)-C(1)-Zr(2)
O(2)-C(3)-C(5)
C(5)-C(3)-C(7)
C(5)-C(3)-C(4)
C(6)-C(5)-C(3)
O(3)-C(7)-C(3)
C(1)-O(1)-Zr(1)
Zr(1)-O(1)-Zr(2)
C(3)-O(2)-Zr(2)
C(7)-O(3)-Zr(1)
78.0(2)
111.5(3)
105.9(4)
113.0(5)
120.6(6)
119.6(4)
177.3(3)
113.0(1)
129.2(2)
123.3(3)
121.3(2)
109.5(1)
127.8
a
C100 is the centroid of the C(9)-C(13) Cp ring; C200 is the
centroid of the C(14)-C(18) Cp ring; C300 is the centroid of
the C(19)-(23) Cp ring; C400 is the centroid of the C(24)-(28) Cp
ring.
Zr(1) in a bidentate fashion. The Zr(1)-O(3) bond
distance (2.239(3) Å) is slightly longer than those of
typical Zr(IV) ketone complexes. The Zr(1)-O(2) (2.271-
(3) Å) and Zr(2)-O(2) (2.296(3) Å) distances are longer
than of those in typical terminal or bridging Zr alkoxide
complexes, such as Cp2Zr(OtBu){Ru(CO)2Cp} (1.910 Å)18
and {Cp*(MeO)2Zr(µ-OMe)}2 (µ-OMe: 2.176 Å).19 The
long Zr-O distances reflect the high Zr coordination
number. The ring formed by Zr(1), O(2), C(3), C(7), and
O(3) is slightly puckered such that C(3) deviates from
the Zr(1)-O(2)-C(7)-O(3) plane by 0.089 Å. Several
related O-chelated keto alkoxide complexes have been
structurally characterized,20-24 of which (η5-C5H4Me)2Zr-
Rea ction Mech a n ism . A reasonable mechanism for
the formation of 3 is provided in Scheme 1. VC reacts
with 1a /b to form the VC adduct Cp2Zr{η2-C(dO)Me}-
(VC)+ (6), which undergoes 1,2 insertion to form Cp2-
Zr{CH2CHClC(dO)CH3}+ (7). Intermediate 7 undergoes
â-Cl elimination to yield MVK and Cp2ZrCl+ (8). The
MVK is trapped by a second equivalent of 1a /b to form
the O-bound MVK adduct Cp2Zr{η2-C(dO)Me}(MVK)+
(9), which in turn undergoes 1,2 addition of the Zr-acyl
group to the CdO bond of MVK to yield Cp2Zr{κ2-OC-
(Me)(CHdCH2)C(dO)Me}+ (10). Intermediate 10 is
ultimately trapped by a third equivalent of 1a /b by
bridging of the alkoxide and acyl ligands to form the
final product 3. The detailed fate of 8 is unknown, but
we have shown previously that [(C5R5)2ZrCl][MeB-
(C6F5)3] species readily decompose by ligand redistribu-
tion reactions.2a We believe that Cp2ZrCl2 and other
Cp2Zr species indicated in Scheme 1 are derived from
8.
(Me){κ2-OCH(p-tol)C(dO)Fe(CO)4}Li(THF)2 is most
24
closely analogous to 3. However, in this case the Zr-
alkoxide unit is terminal rather than bridging, so the
Zr-O(alkoxide) distance (2.13(1) Å) is shorter than that
in 3.
NMR An a lysis of 3. Dissolution of 3 in THF-d8
results in dissociation of the dinuclear dication into a
1:1 mixture of the solvated species [Cp2Zr{η2-C(dO)Me}-
(THF-d8)][MeB(C6F5)3] (4-d8) and [Cp2Zr{κ2-OCMe(CHd
CH2)C(dO)Me}(THF-d8)][MeB(C6F5)3] (5-d8), as shown
in eq 4. Dissolution of 3 in THF followed by removal of
the volatiles and redissolution in CD2Cl2 yields a 1:1
(16) Galeffi, B.; Simard, M.; Wuest, J . D. Inorg. Chem. 1990, 29,
951.
(17) Sun, Y.; Piers, W. E.; Yap, G. P. A. Organometallics 1997, 16,
2509.
(18) Casey, C. P.; J ordan, R. F.; Rheingold, A. L. J . Am. Chem. Soc.
1983, 105, 665.
(19) Heyn, R. H.; Stephan, D. W. Inorg. Chem. 1995, 34, 2804.
(20) Wistuba, T.; Limberg, C.; Kircher, P. Angew. Chem., Int. Ed.
1999, 38, 3037.
(21) (a) Mialane, P.; Anxolabehere-Mallart, E.; Blondin, G.; Nivo-
rojkine, A.; Guilhem, J .; Tchertanova, L.; Cesario, M.; Ravi, N.;
Bominaar, E.; Girerd, J .-J .; Munck, E. Inorg. Chim. Acta 1997, 263,
367. (b) Attia, A. S.; J ung, O. S. Pierpont, C. G. Inorg. Chim. Acta 1994,
226, 91.
(22) Dutta, S.; Peng, S.-M.; Bhattacharya, S. Inorg. Chem. 2000,
39, 2231.
Con fir m a tion of th e Role of MVK. To confirm the
proposed intermediacy of MVK in Scheme 1, the reac-
tion of 1a /b with MVK was studied (Scheme 2). The
reaction of 1a /b with 1 equiv of MVK in CD2Cl2 at -78
°C quantitatively yields MVK adduct 9, which was
1
characterized by H and 13C NMR spectroscopy at -75
(23) Barbaro, P.; Bianchini, C.; Mealli, C.; Meli, A. J . Am. Chem.
Soc. 1991, 113, 3181.
(24) Askham, F. R.; Carroll, K. M.; Briggs, P. M.; Rheingold, A. L.;
Haggerty, B. S. Organometallics 1994, 13, 2139.
(25) Breitmaier, E.; Voelter, W. Carbon-13 NMR Spectroscopy. High-
Resolution Methods and Applications in Organic Chemistry and
Biochemistry, 3rd ed.; VCH Verlagsgesellschaft: Weinheim, Fed. Rep.
Ger., 1987.

2084 Organometallics, Vol. 22, No. 10, 2003
Shen and J ordan
with the 2,1 VC insertion observed for L2Pd{C(dO)Me}+
cations (L2 ) R2bipy, dppp, dmpe) in our previous
studies.4,5 We proposed earlier that 2,1 VC insertion
is favored for L2Pd{C(dO)Me}+ species because the
alternative 1,2 insertion product L2Pd{CH2CHClC(dO)-
Me}+ would be destabilized by the presence of the
electron-withdrawing Cl and acyl substituents on the
â-carbon. Other factors that may contribute to the
preference for 2,1 insertion include olefin distortion
energies and steric interactions between the migrating
acyl group and the VC Cl substituent.28,29 This trend
appears to be general as L2Pd{C(dO)Me}+ species
containing a variety of ancillary ligands (L2 ) Ph2-
PNHC(O)Me,30 (OC)4Fe(µ-dppx),31o-(diphenylphosphino)-
N-benzaldimine,32 1,10-phenanthroline,33 1,2-bis(diphe-
nylphosphino)ethane,34 and dppp35) undergo 2,1 insertion
with other olefins that bear electron-withdrawing groups,
such as acrylates, vinyl acetate, and methyl vinyl
ketone. These results suggest that, in the Cp2Zr{C(d
O)Me}+ case, the electronic preference for 2,1 VC
insertion is overridden by steric factors. As illustrated
in Scheme 3, steric crowding between the Cl and Cp
groups disfavors the VC adduct, insertion product, and
presumably the transition state for 2,1 insertion. Simi-
larly, Busico’s studies of the reaction of LnZrCl2/MAO
(Ln ) rac-dimethylsilylbis(2-methyl-4-phenyl-1-indenyl))
with propylene/CO showed that LnZr{C(dO)R}+ species
undergo 1,2 propylene insertion.7
Sch em e 1
Sch em e 2
Con clu sion s
VC reacts with Cp2Zr{η2-C(dO)Me}+ by 1,2 insertion,
followed by â-Cl elimination, to form Cp2ZrCl+ and
MVK. The MVK is trapped by 2 equiv of Cp2Zr{η2-C(d
O)Me}+ to yield the unusual dinuclear dicationic µ-acyl
(27) (a) Motoyama, Y.; Kurihara, O.; Murata, K.; Aoki, K.; Nish-
iyama, H. Organometallics 2000, 19, 1025. (b) Motoyama, Y.; Murata,
K.; Kurihara, O.; Naitoh, T.; Aoki, K.; Nishiyama, H. Organometallics
1998, 17, 1251 (c) Kegley, S. E.; Walter, K. A.; Bergstrom, D. T.;
MacFarland, D. K.; Young, B. G.; Rheingold, A. L. Organometallics
1993, 12, 2339. (d) Ferrara, M. L.; Orabona, I.; Ruffo, F.; Funicello,
M.; Panunzi, A. Organometallics 1998, 17, 3832. (e) Selvakumar, K.;
Valentini, M.; Wo¨rle, M.; Pregosin, P. S.; Albinati, A. Organometallics
1999, 18, 1207. (f) Castarlenas, R.; Esteruelas, M. A.; Martin, M.; Oro,
L. A. J . Organomet. Chem. 1998, 564, 241. (g) Yi, C. S.; Torres-Lubian,
J . R.; Liu, N.; Rheingold, A. L.; Guzei, I. A. Organometallics 1998, 17,
1257. (h) J edlicka, B.; Ru¨lke, R. E.; Weissensteiner, W.; Ferna´ndez-
Gala´n, R.; J alo´n, F. A.; Manzano, B. R.; Rodr´ıguez-de la Fuente, J .;
Veldman, N.; Kooijman, H.; Spek, A. L. J . Organomet. Chem. 1996,
516, 97. (i) Miller, K. J .; Kitagawa, T. T.; Abu-Omar, M. M. Organo-
metallics 2001, 20, 4403. (j) Ganguly, S.; Roundhill, D. M. Organome-
tallics 1993, 12, 4825. (k) Bennett, M. A.; J in, H.; Li, S.; Rendina, L.
M.; Willis, A. C. J . Am. Chem. Soc. 1995, 117, 8335.
°C. The 13C carbonyl resonance for the coordinated MVK
in 9 is shifted downfield to δ 216.9, versus δ 199.6 for
free MVK, while the MVK vinyl resonances are not
significantly perturbed from the free MVK positions.
These results indicate that the MVK in 9 coordinates
through the oxygen. This result is consistent with the
general trend for R,â-unsaturated carbonyl compounds
to form σ-complexes with electron-deficient/poor-back-
bonding metals,26 rather than η2-olefin π-complexes as
observed for electron-rich metals.27
When 9 is warmed to 23 °C overnight, it converts to
the chelated insertion product 10 (ca. 95% NMR yield).
The 1H NMR spectrum of 10 in CD2Cl2 is complex,
(28) (a) Michalak, A.; Ziegler, T. J . Am. Chem. Soc. 2001, 123, 12266.
(b) Michalak, A.; Ziegler, T. Organometallics 1999, 18, 3998. (c) von
Schenck, H.; Stro¨mberg, S.; Zetterberg, K.; Ludwig, M.; Åkermark, B.;
Svensson, M. Organometallics 2001, 20, 2813.
1
possibly due to oligomerization. However, the H NMR
(29) For DFT studies of insertion reactions of Pd-acyl species see:
(a) Margl, P.; Ziegler, T. J . Am. Chem. Soc. 1996, 118, 7337. (b) Margl,
P.; Zielger, T. Organometallics 1996, 15, 5519. (c) Cavallo, L. J . Am.
Chem. Soc. 1999, 121, 4238.
(30) Braunstein, P.; Frison, C.; Morise, X. Angew. Chem., Int. Ed.
2000, 39, 2867.
(31) dppx ) Ph2PNHPPh2. Braunstein, P.; Durand, J .; Knorr, M.;
Strohmann, C. J . Chem. Soc., Chem. Commun. 2001, 211.
(32) (a) Reddy, K. R.; Surekha, K.; Lee, G. H.; Peng, S. M.; Chen, J .
T.; Liu, S. T. Organometallics 2001, 20, 1292. (b) Reddy, K. R.; Chen,
C. L.; Liu, Y. H.; Peng, S. M.; Chen, J . T.; Liu, S. T. Organometallics
1999, 18, 2574.
(33) Rix, F. C.; Brookhart, M.; White, P. S. J . Am. Chem. Soc. 1996,
118, 4746.
(34) Ozawa, F.; Hayashi, T.; Koide, H.; Yamamoto, A. J . Chem. Soc.,
Chem. Commun. 1991, 1469.
(35) Dekker, G. P. C. M.; Elsevier, C. J .; Vrieze, K.; van Leeuwen,
P. W. N. M.; Roobeek, C. F. J . Organomet. Chem. 1992, 430, 357.
spectrum of 10 in THF-d8 is identical to that of 5-d8
produced by dissolution of 3 in THF-d8 (eq 4).
Regioch em istr y of VC In ser tion of Meta l Acyl
Com p lexes. The key result from these studies is that
Cp2Zr{η2-C(dO)Me}+ reacts with VC by 1,2 insertion
(i.e., 6 f 7 in Scheme 1). This regioselectivity contrasts
(26) (a) Shambayati, S.; Crowe, W. E.; Schreiber, S. L. Angew.
Chem., Int. Ed. Engl. 1990, 29, 256. (b) Shambayati, S.; Schreiber, S.
L. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.;
Pergamon: Oxford, U.K., 1991; Vol. 1; p 283. (c) Poll, T.; Metter, J .
O.; Helmchen, G. Angew. Chem., Int. Ed. Engl. 1985, 24, 112. (d) Lewis,
F. D.; Oxman, J . D.; Huffman, J . C. J . Am. Chem. Soc. 1984, 106, 466.
(e) Honeychuck, R. V.; Bonnesen, P. V.; Farahi, J .; Hersh, W. H. J .
Org. Chem. 1987, 52, 5293.

Cationic Zirconium(IV) Acyl Carbonyl Complex
Organometallics, Vol. 22, No. 10, 2003 2085
[Cp 2Zr {η2-C(dO)Me}(CO)][MeB(C6F 5)3] (O-in sid e/O-
ou tsid e: 1a /1b). A CD2Cl2 solution of this compound was
prepared in a valved NMR tube by carbonylation of Cp2ZrMe-
(µ-Me)B(C6F5)3 as described previously.5 The isomer ratio 1a /b
is 5:1 at 23 °C and 2.7:1 at -75 °C. 1H NMR (CD2Cl2, -75 °C):
δ 6.09 (s, 2.7H, Cp 1a ), 5.99 (s, 7.3H, Cp 1b), 3.17 (s, 2.2H,
C(dO)Me 1a ), 3.15 (s, 0.8H, C(dO)Me 1b), 0.40 (br s, 3H). 13C-
{1H} NMR (CD2Cl2, -75 °C): δ 305.2, 297.1, 198.0, 191.8,
109.1, 107.8, 34.0, 33.1.
Sch em e 3
Syn th esis of 3 by Rea ction of 1 w ith VC. A valved NMR
tube containing a clear solution of 1a /b (0.0398 mmol) in CD2-
Cl2 (0.5 mL) was frozen, evacuated under vacuum, and charged
with VC (0.557 mmol) at - 196 °C. The tube was warmed to
23 °C and briefly shaken. A yellow crystalline solid formed
within 1 h. The tube was maintained at 23 °C overnight. The
supernatant was decanted under N2. The crystalline solid was
washed with fresh CH2Cl2 (3 × 0.5 mL) and dried under
vacuum to afford 3 as a yellow solid (18.2 mg, 79%). The solid
was dissolved in THF-d8 and analyzed by NMR, which showed
that a 1.08:1 mixture of [Cp2Zr{η2-C(dO)Me}(THF-d8)+][MeB-
(C6F5)3] (4-d8) and [Cp2Zr{κ2-OCMe(CHdCH2)C(dO)Me}(THF-
d8)][MeB(C6F5)3] (5-d8) was present. NMR data for these
species are given below.
µ-(keto-alkoxide) complex 3. The 1,2 VC insertion re-
giochemistry contrasts with the 2,1 regiochemistry
observed for VC insertion of L2Pd{C(dO)Me}+ species
and appears to be controlled by steric factors.
Syn th esis of 3 by Rea ction of 1 w ith MVK. A valved
NMR tube containing a solution of 1a /b (0.0398 mmol) in CD2-
Cl2 (0.5 mL) was frozen, evacuated under vacuum, and charged
with MVK (0.0199 mmol) at - 196 °C. The tube was warmed
to 23 °C and briefly shaken. A yellow crystalline solid started
to form within 1 h. The tube was maintained at 23 °C
overnight. The pale yellow supernatant was decanted under
N2. The crystalline solid was washed with CH2Cl2 (3 × 0.5 mL)
and dried under vacuum to afford a yellow solid (29.9 mg,
91%). Anal. Calcd for C66H38B2F30O3Zr: C, 47.95; H, 2.32.
Found: C, 47.61; H, 2.40. The 1H and 13C NMR spectra in
THF-d8 of this product matched those of 3 obtained from the
reaction of 1 and VC and are consistent with the dissociation
of 3 into a 1:1 mixture of [Cp2Zr{η2-C(dO)Me}(THF-d8)][MeB-
(C6F5)3] (4-d8) and [Cp2Zr{κ2-OCMe(CHdCH2)C(dO)Me}(THF-
d8)][MeB(C6F5)3] (5-d8). Data for 4-d8: 1H NMR (THF-d8): δ
6.12 (s, 10H), 3.19 (s, 3H). 13C{1H} NMR (THF-d8): δ 318.8
(Zr{C(dO)Me}), 111.5 (Cp), 33.5 (Zr{C(dO)Me}). 5-d8: 1H
NMR (THF-d8): δ 6.34 (s, 10H), 6.16 (dd, J ) 17, 10, 1H), 5.50
(dd, J ) 17, 1, 1H), 5.34 (dd, J ) 10, 1, 1H), 2.52 (s, 3H), 1.52
(s, 3H). 13C{1H} NMR (THF-d8): δ 231.5 (Zr-OdC), 138.2
(CHdCH2), 117.1 (CHdCH2), 116.3 (Cp), 98.1 (tert-C), 24.9
(Me), 24.7 (Me).
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were performed
using drybox or Schlenk techniques under an N2 atmosphere
or on a high-vacuum line unless otherwise indicated. Solvents
were distilled from appropriate drying/deoxygenating agents
(THF and THF-d8: sodium benzophenone ketyl; CH2Cl2 and
C6H5Cl: CaH2; CD2Cl2 and C6D5Cl: P4O10). Pentane and
benzene were purified by passage through columns of activated
alumina and BASF R3-11 oxygen removal catalyst. Nitrogen
was purified by passage through columns containing activated
molecular sieves and Q-5 oxygen scavenger. CO was purchased
from Matheson. B(C6F5)3 was supplied by Boulder Scientific.
Cp2ZrMe2 was synthesized according to the literature proce-
dure.36 VC and all other chemicals were purchased from
Aldrich and used without further purification, except for MVK,
which was dried by 3 Å molecular sieves and stored under
vacuum at -20 °C. VC and MVK were quantified by use of a
calibrated gas bulb. Elemental analyses were performed by
Midwest Microlab.
NMR spectra were recorded on Bruker DMX-500 or DRX-
400 spectrometers, in Teflon-valved tubes, at 23 °C unless
1
otherwise indicated. H and 13C chemical shifts are reported
versus SiMe4 and were determined by reference to residual
1H and 13C solvent signals. 11B chemical shifts are referenced
to external Et2O‚BF3. 19F chemical shifts are reported relative
to CFCl3. All coupling constants are reported in Hz. Nuclear
Rea ction of 3 w ith THF . A sample of 3 prepared from 1a /b
and 0.5 equiv of MVK was dissolved in THF to form a clear,
pale yellow solution. The volatiles were removed under
vacuum, and CH2Cl2 (0.5 mL) was added to form a clear, pale
yellow solution. The volatiles were removed under vacuum.
The CH2Cl2 treatment was repeated four times to ensure
complete removal of free THF. Finally CD2Cl2 (0.5 mL) was
added by vacuum transfer. 1H and 13C NMR spectra were
obtained, which established that a 1:1 mixture of [Cp2Zr{η2-
C(dO)Me}(THF)][MeB(C6F5)3] (4) and [Cp2Zr{κ2-OCMe(CHd
CH2)C(dO)Me}(THF)][MeB(C6F5)3] (5) had formed; THF ex-
change between these species is slow on the NMR time scale
at 23 °C in CD2Cl2 solution. Data for 4: 1H NMR (CD2Cl2): δ
5.98 (s, 10H), 4.00 (br m, Zr-THF), 3.13 (s, 3H), 2.05 (br m,
4H, Zr-THF). 13C{1H} NMR (CD2Cl2): δ 317.5 (Zr{C(dO)Me}),
110.5 (Cp), 76.7 (Zr-THF), 33.9 (Zr{C(dO)Me}), 25.9 (Zr-THF).
Data for 5: 1H NMR (CD2Cl2): δ 6.23 (10H), 5.99 (dd, J ) 17,
11, 1H), 5.44 (dd, J ) 17, 1, 1H), 5.39 (dd, J ) 11, 1, 1H), 4.18
(m, 4H, Zr-THF), 2.45 (s, 3H), 2.14 (m, 4H, Zr-THF), 1.48 (s,
3H). 13C{1H} NMR (CD2Cl2): δ 230.6 (Zr-OdC), 136.4 (CHd
CH2), 117.7 (CHdCH2), 115.4 (Cp), 74.8 (br s, Zr-THF), 25.7
(br s, Zr-THF), 25.0 (Me), 24.8 (Me); tert-C resonance was not
observed. These NMR assignments were confirmed by COSY,
DEPT, and HMQC experiments.
1
Overhauser effect spectroscopy (NOESY), H-1H correlation
spectroscopy (COSY), DEPT (distortionless enhancement by
polarization transfer), and heteronuclear multiple quantum
correlation spectroscopy (HMQC) spectra were acquired and
processed using standard Bruker programs.
NMR spectra for cationic complexes contain resonances for
the free MeB(C6F5)3-. 1H NMR (CD2Cl2, -75 °C): δ 0.34 (br s,
MeB). 13C NMR (CD2Cl2, -75 °C): δ 147.4 (dd, J ) 236, 10,
C6F5), 136.9 (d, J ) 242, C6F5), 135.9 (dd, J ) 236, 10, C6F5),
127.6 (br s, ipso-C6F5), 9.22 (br s, MeB). 11B NMR (CD2Cl2, -75
°C): δ -14 (br s). 19F NMR (CD2Cl2, -75 °C): δ -134.6 (br s,
8F, Fortho), -168.7 (t, J ) 21, 4F, Fpara), -170.9 (t, J ) 17, 8F,
F
meta).
Da ta for F r ee MVK. 1H NMR (CD2Cl2): δ 6.28 (dd, J )
18, 10, 1H), 6.15 (dd, J ) 18, 1, 1H), 5.88 (dd, J ) 10, 1, 1H),
2.24 (s, 3H). 13C NMR (CD2Cl2): δ 198.9, 137.8, 129.0, 26.5.
1H NMR (CD2Cl2, -75 °C): δ 6.19 (m, 2H, coincidental vinyl
H), 5.96 (dd, J ) 6.5, 5.0, 1H), 2.23 (s, 3H). 13C NMR (CD2-
Cl2): δ 199.6, 136.9, 130.1, 25.9.
(36) Samuel, E.; Rausch, M. D. J . Am. Chem. Soc. 1973, 95, 19.

2086 Organometallics, Vol. 22, No. 10, 2003
Shen and J ordan
Ta ble 3. Su m m a r y of Cr ysta llogr a p h ic Da ta for
Com p ou n d s 1a a n d 3
charged with MVK (0.0398 mmol) at - 196 °C. The mixture
was warmed to -78 °C. A 1H NMR spectrum was obtained
and established that 9 had formed quantitatively. Two Cp
resonances were observed in the 1H and 13C NMR spectra
which is ascribed to the presence of two isomers, probably
O-inside and O-outside isomers. 1H NMR (CD2Cl2, -75 °C): δ
6.78 (dd, J ) 14, 3, 1H, vinyl), 6.59 (m, 2H, vinyl), 6.35 (s, 1H,
Cp of minor isomer), 5.94 (s, 9H, Cp of major isomer), 3.06 (s,
3H), 2.65 (s, 3H). 13C{1H} NMR (CD2Cl2, -75 °C): δ 317.7,
216.9, 141.3, 135.1, 115.2 (Cp of minor isomer), 110.1 (Cp of
major isomer), 34.0, 26.1.
1a
3
formula
fw
cryst size (mm)
d(calc), Mg/m3
cryst syst
space group
a, Å
C
32H16BF15O2Zr
C66H38B2F30O3Zr2
1653.02
819.48
0.24 × 0.08 × 0.08 0.15 × 0.10 × 0.07
1.806
1.818
triclinic
P1h
12.508(3)
12.831(3)
21.375(5)
94.578(4)
92.907(3)
117.425(3)
3020(1)
monoclinic
P21/ c
12.676(2)
16.046(2)
15.604(2)
b, Å
c, Å
Gen er a tion of [Cp 2Zr {κ2-OCMe(CHdCH2)C(dO)Me}]-
[MeB(C6F 5)3] (10). A solution of 9 generated as described
above was maintained at 23 °C overnight. The volatiles were
removed under vacuum, and THF-d8 was added by vacuum
transfer. A 1H NMR spectrum was obtained and showed that
R, deg
â, deg
108.280(3)
γ, deg
V, Å3
3013.7(8)
4
100
Bruker SMART
APEX
Z
2
100
T (K)
diffractometer
1
Bruker SMART
APEX
5-d8 had formed in ca. 95% NMR yield. H NMR (THF-d8): δ
6.35 (s, 10H), 6.16 (dd, J ) 17, 10, 1H), 5.50 (dd, J ) 17, 1,
1H), 5.34 (dd, J ) 10, 1, 1H), 2.51 (s, 3H), 1.52 (s, 3H).
radiation, λ (Å)
2θ range (deg)
Mo KR, 0.71073
2.12-25.03
-14, 15; -15, 19;
-16, 18
Mo KR, 0.71073
2.13-28.32
-16, 16; -17, 17;
-18, 18
X-r a y Cr ysta llogr a p h ic An a lysis of 1a a n d 3. Single
crystals of 1a were grown from CH2Cl2 at -80 °C. Single
crystals of 3 were obtained from the reaction of 1a /b with MVK
in CD2Cl2 at 23 °C. Crystal data, data collection details, and
solution and refinement procedures are summarized in Table
3, and full details are provided in the Supporting Information.
The ORTEP diagrams were drawn with 50% probability
ellipsoids. All non-hydrogen atoms were refined with aniso-
tropic displacement coefficients. All hydrogen atoms were
included in the structure factor calculation at idealized posi-
tions and were allowed to ride on the neighboring atoms with
relative anisotropic displacement coefficients.
index ranges: h; k; l
no. of reflns collected
no. of unique reflns
no. of obsd reflns
Rint
15 102
35 480
5325
14 114
I > 2σ(I), 5119
I > 2σ(I), 12 569
0.0284
0.0326
µ, mm-1
0.490
0.489
max./min. transmn
structure solution
refinement method
1.0, 0.895
direct methodsa
full-matrix least
squares on F2
1.0, 0.777
direct methodsa
full-matrix least
squares on F2
14114/0/933
no. of data/restraints/ 5325/0/463
params
adsorp corr
SADABS based on SADABS based on
redundant
redundant
diffractions
diffractions
GOF on F2
1.239
1.090
Ack n ow led gm en t. We thank Dr. Ian Steele for
assistance with X-ray diffraction analyses. This work
was supported by the Edison Polymer Innovation Cor-
poration and the Department of Energy (DE-FG02-
00ER15036).
R indices (I > 2σ(I))b
R1 ) 0.0506,
wR2 ) 0.0985
R1 ) 0.0536,
wR2 ) 0.0997
0.460, -0.706
R1 ) 0.0611,
wR2 ) 0.1497
R1 ) 0.0685,
wR2 ) 0.1552
3.809, -1.318
R indices (all data)b
max. diff peak/hole
(e/Å3)
a
SHELXTL-Version 5.1; Bruker Analytical X-ray Systems:
Su p p or tin g In for m a tion Ava ila ble: Text, figures, and
tables that give crystallographic data for 1a and 3. This
material is available free of charge via the Internet at
http://pubs.acs.org.
b
2
Madison, WI. R1 ) ∑||Fo| - |Fc||/∑|Fo| and wR2 ) [∑[w(Fo
-
Fc2)2]/∑[w(Fo2)2]]1/2, where w ) q/[σ2(Fo2) + (aP)2 + bP].
Gen er ation of [Cp 2Zr {η2-C(dO)Me}(MVK)][MeB(C6F5)3]
(9). A solution of 1a /b (0.0398 mmol) in CD2Cl2 (0.5 mL) was
OM0210311