New reaction pathways for μ-η1,η2-allenyl ligands: On-off allenyl coordination and CO insertion into the hydrocarbyl bridge in Ru2(CO)6(μ-PPh2){μ-η1,η 2α,β-C(Ph)=C=CPh2}

Article abstract of DOI:10.1021/om9607208

The binuclear allenyl complex Ru₂(CO)₆(μ-PPh₂){μ-η ¹,η²_α,β-C(Ph)=C=CPh₂} (1) reacts with bis-(diphenylphosphino)methane (dppm) to afford Ru₂(CO)₄-(μ-PPh₂)(μ-dppm){μ-η ¹,η²-C(O)C(Ph)=C=CPh₂} (2) containing an acylallenyl ligand and Ru₂(CO)₄(μ-PPh₂)(μ-dppm) {μ-η¹,η² _α,β-C(Ph)=C=CPh₂} (4). With bis(diphenylphosphino)ethane (dppe), 1 affords Ru₂(CO)₅(μ-PPh₂)-(η ²-dppe){η¹-C(Ph)=C=CPh₂} (3), which contains a terminal η¹-coordinated allenyl fragment. The X-ray structures of 2-4 are reported.

Full text of DOI:10.1021/om9607208

Organometallics 1997, 16, 297-300
297
New Rea ction P a th w a ys for µ-η1,η2-Allen yl Liga n d s:
On -Off Allen yl Coor d in a tion a n d CO In ser tion in to th e
Hyd r oca r byl Br id ge in
Ru 2(CO)6(µ-P P h 2){µ-η1,η2r,â-C(P h )dCdCP h 2}
Peter Blenkiron,† J ohn F. Corrigan,‡ Nicholas J . Taylor,‡ and Arthur J . Carty*,†,‡
The Steacie Institute for Molecular Sciences, National Research Council of Canada,
100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6, and Guelph-Waterloo Centre for
Graduate Work in Chemistry, Waterloo Campus, Department of Chemistry, University of
Waterloo, Waterloo, Ontario, Canada N2L 3G1
Simon Doherty,* Mark R. J . Elsegood, and William Clegg
Department of Chemistry, Bedson Building, University of Newcastle,
Newcastle upon Tyne NE1 7RU, United Kingdom
Received August 21, 1996X
Summary: The binuclear allenyl complex Ru2(CO)6(µ-
PPh2){µ-η1,η2R,â-C(Ph)dCdCPh2} (1) reacts with bis-
(diphenylphosphino)methane (dppm) to afford Ru2(CO)4-
(µ-PPh2)(µ-dppm){µ-η1,η2-C(O)C(Ph)dCdCPh2} (2) con-
taining an acylallenyl ligand and Ru2(CO)4(µ-PPh2)(µ-
dppm){µ-η1,η2R,â-C(Ph)dCdCPh2} (4). With bis(diphe-
nylphosphino)ethane (dppe), 1 affords Ru2(CO)5(µ-PPh2)-
(η2-dppe){η1-C(Ph)dCdCPh2} (3), which contains a
terminal η1-coordinated allenyl fragment. The X-ray
structures of 2-4 are reported.
plexes M2(CO)6(µ-PPh2){µ-η1,η2R,â-C(Ph)dCdCH2} (M )
Ru, Os)8 and Pd2(PPh3)2(µ-Cl)(µ-η3-C(H)dCdCH2).9
Herein, we report new reaction pathways for the
allenyl ligand in Ru2(CO)6(µ-PPh2){µ-η1,η2R,â-C(Ph)dCd
CPh2} (1)10 including (i) a transformation of the µ-η1,η2
-
R,â
allenyl ligand into a terminal η1-metalloallene via
displacement of the coordinated CR-Câ double bond and
(ii) a dppm-induced migratory insertion-elimination
sequence for an allenyl ligand. The interconversion of
terminal and bridging allenyl ligands has no literature
precedent and there is only a single report of the reac-
tivity of binuclear allenyl complexes with diphosphines.8
The reactivity of the cumulated C3 hydrocarbyl group
sC(R)dCdCR′2 (allenyl) has been much less extensively
developed than that of unsaturated C2 groups (e.g.,
alkynyl and alkenyl). Several recent developments
suggest that mono- and polynuclear allenyl complexes
undergo a variety of novel transformations which herald
the beginning of an exciting organometallic chemistry
for this fragment.1 Examples include η1- to η3-bonding
changes at a mononuclear center,2 the generation of
dimetallocyclopentanes and pentenes via nucleophilic
We have previously detailed the reactivity of Ru2-
(CO)6(µ-PPh2){µ-η1,η2â,γ-C(Ph)dCdCH2} (5) toward
mono-4 and bidentate8 phosphines. Although closely
related, 1 and 5 differ structurally in that the π-coor-
dinated allenyl ligand in 1 is attached via the CR-Câ
bond and by the Câ-Cγ bond in 5. We have initiated
the current study in an effort to determine how the
bonding mode of the allenyl ligand impacts on chemical
behavior.
3
attack at Câ in µ-η1,η2R,â-allenyl complexes,4 azatrim-
ethylenemethanes from Câ addition of amines in η3-
platinum complexes,5 cycloaddition and coupling reac-
tions with dienophiles and alkynes,6 the mutual iso-
merization of (η1-allenyl)- and (η1-propargyl)platinum
complexes,7 new ligand coupling/insertion reactions,8
and new allenyl bonding modes in the binuclear com-
Stirring a room temperature n-heptane solution of 1
(0.20 g, 0.24 mmol) with dppm (0.090 g, 0.23 mmol) for
3 h afforded an orange precipitate which, on recrystal-
lization, gave Ru2(CO)4(µ-PPh2)(µ-dppm){µ-η1,η2-C(O)C-
(Ph)dCdCPh2} (2) in 80% yield.11 Under similar con-
ditions the reaction of 1 with dppe afforded Ru2(CO)5(µ-
PPh2)(η2-dppe){η1-C(Ph)dCdCPh2} (3) as the sole product
(71% yield) after chromatographic workup.12 In each
case reaction monitoring by IR spectroscopy showed only
* Authors to whom correspondence should be addressed.
† Steacie Institute.
‡ GWC2.
X Abstract published in Advance ACS Abstracts, J anuary 1, 1997.
(1) For recent comprehensive reviews see: (a) Wojcicki, A. New J .
Chem. 1994, 18, 61. (b) Doherty, S.; Corrigan, J . F.; Carty, A. J .; Sappa,
E. Adv. Organomet. Chem. 1995, 37, 39.
(8) Carleton, N.; Corrigan, J . F.; Doherty, S.; Pixner, R. Sun, Y.;
Taylor, N. J .; Carty, A. J . Organometallics 1994, 13, 4179.
(9) Ogoshi, S.; Tsutsumi, K.; Ooi, M.; Kurosawa, H. J . Am. Chem.
Soc. 1995, 117, 10415.
(2) (a) Huang, T.-M.; Chen, J .-T.; Lee, G.-H.; Wang, Y. J . Am. Chem.
Soc. 1993, 115, 1170. (b) Blosser, P. W.; Schimpff, D. G.; Gallucci, J .
C.; Wojcicki, A. Organometallics 1993, 12, 1993. (c) Huang, T.-M.; Hsu,
R.-H.; Yang, C.-S.; Chen, J .-T.; Lee, G.-H.; Wang, Y. Organometallics
1994, 13, 3657.
(3) See Scheme 1 for the designation of CR, Câ, and Cγ.
(4) Breckenridge, S. M.; Taylor, N. J .; Carty, A. J . Organometallics
1991, 10, 837.
(5) (a) Baize, M. W.; Plantevin, V.; Gallucci, J . C.; Wojcicki, A. Inorg.
Chim. Acta 1995, 235, 1. (b) Baize, M. W.; Blosser, P. W.; Plantevin,
V.; Schimpff, D. G.; Gallucci, J . C.; Wojcicki, A. Organometallics 1996,
15, 164.
(6) (a) Shu, H.-G.; Shiu, L.-H.; Wang, S.-H.; Wang, S.-L.; Lee, G.-
H.; Peng, S.-M.; Liu, R.-S. J . Am. Chem. Soc. 1996, 118, 530. (b) Su,
C.-C.; Chen, J .-T.; Lee, G.-H.; Wang, Y. J . Am. Chem. Soc. 1994, 116,
4999. (c) Plantevin, V.; Blosser, P. W.; Gallucci, J . C.; Wojcicki, A.
Organometallics 1994, 13, 3651.
(10) Nucciarone, D.; Taylor, N. J .; Carty, A. J . Organometallics 1986,
5, 1179.
(11) Spectroscopic data for 2: IR (CH2Cl2) ν(CO)/cm-1, 2025 w, 2010
s, 1967 m, 1961 sh; 1H NMR (CDCl3) δ 7.61-5.82 (m, 45H, Ph), 4.39
(m, 1H, Ph2PCH2), 3.93 (m, 1H, Ph2PCH2); 31P{1H} NMR (CDCl3) δ
129.3 (dd, J PµP
) 139.0 Hz, J
4.02d.ppFmound: C, 63.98; H, 4.22.
) 23.2 Hz, J PµPdppm ) 17.5 Hz, µ-P), 29.3 (dd, J P
dppmPdppm
dppm
) 17.5 Hz, dppm), 2.5 (dd, J P
) 139.0 Hz,
dppmPdppm
PµPdppm
J PµP
) 23.2 Hz, dppm). Anal. Calc for C63H47O5P3Ru2: C, 64.17; H,
(12) Spectroscopic data for 3: IR (C6H12) ν(CO)/cm-1, 2005 sh, 1992
s, 1980 sh, 1946 m, 1923 m; 1H NMR (CDCl3) δ 7.81-6.71 (m, 45H,
Ph), 2.10 (dd, J PH ) 20.0 Hz, J HH ) 2.7 Hz, 2H, Ph2PCH2), 2.06 (t, J PH
) 5.2 Hz, J HH ) 5.2 Hz, 2H, Ph2PCH2); 31P{1H} NMR (CDCl3) δ 107.2
(dd, J PµP
132.0 Hz, J P
) 132.0 Hz, J PµP
) 14.0 Hz, µ-P), 63.0 (dd, J PµP
)
dppe
dppe
dppe
) 14.0 Hz, dppe), 58.0 (dd, J PµP
) 14.0 Hz,
dppePdppe
dppe
(7) Ogoshi, S.; Fukunishi, Y.; Tsutsumi, K.; Kurosawa, H. J . Chem.
Soc., Chem. Commun. 1995, 2485.
J P
) 14.0 Hz dppe). Anal. Calc for C64H49O5P3Ru2: C, 64.43; H,
dppePdppe
4.14. Found: C, 63.80; H, 4.19.
S0276-7333(96)00720-0 CCC: $14.00 © 1997 American Chemical Society

298 Organometallics, Vol. 16, No. 3, 1997
Communications
F igu r e 2. Molecular structure of Ru2(CO)5(µ-PPh2)(η2-
dppe){η1-C(Ph)dCdCPh2} (3) with the non-hydrogen atom-
labeling scheme. Important bond lengths and angles not
mentioned in the text are as follows: Ru(1)-Ru(2) 2.926-
(1) Å; Ru(1)-C(6)-C(7) 120.6(2), P(2)-Ru(2)-P(3) 85.8(1),
C(6)-Ru(1)-Ru(2) 159.2(1), Ru(1)-P(1)-Ru(2) 76.5(1)°.
F igu r e 1. Molecular structure of Ru2(CO)4(µ-PPh2)(µ-
dppm){µ-η1,η2-C(O)C(Ph)dCdCPh2} (2) with the non-
hydrogen atom-labeling scheme. Important bond lengths
and angles not mentioned in the text are as follows: C(1)-
C(2) 1.510(14), C(1)-O(1) 1.213(12), Ru(1)-Ru(2) 2.9697
(12) Å; Ru(2)-C(1)-O(1) 130.1(8), O(1)-C(1)-C(2) 122.9-
(9), C(1)-C(2)-C(3) 118.5(9), P(1)-Ru(1)-P(2) 99.26(9),
P(1)-Ru(2)-P(3) 94.93(9), Ru(1)-P(1)-Ru(2) 77.56(8)°.
the dihedral angle of 82.4° between the planes defined
by C(4)-C(11)-C(17) and C(2)-C(1)-C(5). However,
the η2-coordination of C(2)-C(3) and the steric conges-
tion imposed by the bulky phenyl substituents on P(1)
and P(2) creates a further distortion from linearity in
the allenic backbone of 2 (C(2)-C(3)-C(4) ) 136.5(9)°).
The molecular structure of 3 (Figure 2) revealed a
novel η1-coordination mode for the allenyl ligand. Thus,
in contrast to 2, the η1-allenyl linkage to the metal in 3
remains intact, although a significant elongation of the
Ru-Cσ bond results (Ru(1)-C(6) ) 2.158(3) Å; cf. 2.101-
(8) Å in 1). Equally, the displacement of the π-coordi-
nated CR-Câ bond in precursor 1 causes a contraction
in allenic bond lengths (C(6)-C(7) ) 1.293(5), C(7)-C(8)
) 1.328(5) Å) to give values typical for terminal allenyl
complexes.2c,18 The near-linear hydrocarbyl backbone
in 3 (C(6)-C(7)-C(8) ) 175.5(3) Å) and the dihedral
angle of 83.4° formed between the Ru(1)-C(6)-C(9) and
C(15)-C(8)-C(21) planes is consistent with a metal-
loallene designation. In the formation of 3, the loss of
a CO ligand and slippage of the µ-η1,η2-coordinated
allenyl to η1-mode generates two vacant sites on Ru(2)
to which the dppe ligand becomes coordinated as a
chelating group with one arm binding trans (P(1)-Ru-
(2)-P(2) ) 160.8(1)°) and one cis (P(1)-Ru(2)-P(3) )
94.93(9)°) to the phosphido bridge, consistent with
the formation of the final isolated product. The 31P
NMR spectra for 2 and 3 each showed three distinct sets
of resonances indicating incorporation of the diphos-
phine ligand. However, their disparate chemical shifts
and J values suggested different reaction pathways for
these phosphines. Single-crystal X-ray studies were
therefore carried out on 213 and 314 to elucidate their
structures (Figure 1).
The most notable feature of 2 is the acylallenyl ligand,
formally derived from the insertion of CO into the Ru-
CR bond of 1. The resulting ligand is σ-bound to Ru(2)
through the carbonyl carbon (Ru(2)-C(1) ) 2.053(10)
Å) and attached to Ru(1) via an η2 interaction with CR-
Câ (Ru(1)-C(2) ) 2.374(10) Å, Ru(1)-C(3) ) 2.105(10)
Å). The incorporation of a CO group in 2 effects a
significant elongation of the CR-Câ bond10 (C(2)-C(3)
) 1.438(14) Å vs 1.382(11) Å in 1) while the outer
uncoordinated Câ-Cγ bond remains essentially un-
changed (C(3)-C(4) ) 1.340(14) Å). The retention of
allenic character in the new fragment is highlighted by
(13) Crystal data for 2‚CH2Cl2.0.5C6H14
: C67H56Cl2O5P3Ru2, M )
1307.1; triclinic, space group P1h; a ) 11.7781(10), b ) 14.1291(11), c
) 19.130(2) Å; R ) 89.499(2), â ) 73.406(2), γ ) 67.870(2)°; V ) 2808.6-
(4) Å3, Z ) 2, T ) 160 K, Dc ) 1.546 g cm-3, F(000) ) 1330, λ ) 0.710 73
Å, µ(Mo KR) ) 0.771 mm-1. Intensity data were collected on a crystal
of dimensions 0.16 × 0.08 × 0.07 mm mounted on a Siemens SMART
CCD area detector diffractometer. Of 28 920 reflections measured (θmax
) 25.0°), 9857 were unique (Rint ) 0.108). Semi-empirical absorption
corrections were applied (transmission 0.605-0.986). The structure
was solved by Patterson synthesis and refinement based on F2 with
statistical-based weighting scheme, anisotropic displacement param-
eters, constrained isotropic H atoms, and restraints on possibly
disordered (unresolved) n-hexane solvent; final wR2 ) {Σ[w(Fo2 - Fc2)2]/
Σ[w(Fo)2)2]}1/2 ) 0.223 for all data. Conventional R ) 0.100 on F values
J PµP
couplings of 132.0 and 14.0 Hz, respectively.
dppe
The conversion of a µ-η1,η2R,â-bound allenyl ligand into
a terminal metalloallene is unprecedented in poly-
nuclear chemistry. However, Wojcicki and co-workers
have demonstrated the conversion of an η3-propargyl/
allenyl ligand to an η1 arrangement in the treatment of
the platinum cation [(Ph3P)2Pt(η3-CH2CCPh)]+ with
excess PMe3 or CO.2b
of 7378 reflections having Fo > 2σ(Fo2), S ) 1.26 on F2 for all data,
2
713 refined parameters and 39 restraints.
(14) Crystal data for 3‚CH2Cl2: C65H51Cl2O5P3Ru2, M ) 1278.0;
monoclinic, space group P21/n; a ) 13.923(2), b ) 19.567(3), c ) 21.089-
(3) Å; â ) 94.96(2)°; V ) 5723.7(14) Å3, Z ) 4, T ) 200 K, Dc ) 1.483
g cm-3, F(000) ) 2592, λ ) 0.710 73 Å, µ(Mo KR) ) 7.55 cm-1. Intensity
data were collected on a crystal of dimensions 0.30 × 0.40 × 0.74 ×
0.65 mm mounted on a Siemens R3m/V diffractometer by the ω scan
method (2θ < 50°). An absorption correction (face-indexed numerical)
was applied (transmission 0.729-0.817). Of 10 116 reflections mea-
sured, 8255 were considered observed [F > 6.0σ(F)]. The structure was
solved (Patterson, Fourier methods) and refined (full-matrix least-
squares) using the Siemens SHELXTL PLUS program, giving final R
and Rw values (based on Fo2) of 0.0302 and 0.0334, respectively.
Room-temperature solutions of 2 readily lose CO over
24 h to afford Ru2(CO)4(µ-PPh2)(µ-dppm){µ-η1,η2
-
R,â
C(Ph)dCdCPh2} (4) (Scheme 1), a transformation which
also occurs quantitatively and more rapidly at elevated
(15) (a) Wouters, J . M. A; Klein, R. A.; Elsevier, C. J .; Zoutberg, M.
C.; Stam, C. H. Organometallics 1993, 12, 3864. (b) Wouters, J . M. A;
Klein, R. A.; Elsevier, C. J .; Haming, L.; Stam, C. H. Organometallics
1994, 13, 4586. (c) Blosser, P. W.; Gallucci, J . C.; Wojcicki, A. J . Am.
Chem. Soc. 1993, 115, 2994.

Communications
Organometallics, Vol. 16, No. 3, 1997 299
Sch em e 1
F igu r e 3. Molecular structure of Ru2(CO)4(µ-PPh2)(µ-
dppm){µ-η1,η2R,â-C(Ph)dCdCPh2} (4) with the non-hydro-
gen atom-labeling scheme. Important bond lengths and
angles not mentioned in the text are as follows: Ru(1)-
Ru(2) 2.819(1), C(5)-C(6) 1.402(6), C(6)-C(7) 1.341(5) Å;
C(5)-C(6)-C(7) 140.2(3), Ru(1)-C(5)-C(6) 124.9(3), Ru-
(2)-C(6)-C(7) 139.3(3), P(1)-Ru(1)-P(2) 90.4(1), P(1)-Ru-
(2)-P(3) 94.7(1), Ru(1)-P(1)-Ru(2) 72.9(1)°.
nuclear η1-propargyl complexes.18 Wojcicki and co-
workers have described the binuclear complex CpRu-
(CO)Fe(CO)3{µ-η3,η2-C(O)C(Ph)dCdCH2} which features
a 5-electron donor acylallenyl ligand in which both
allenyl CdC bonds are π-coordinated to a metal center.19
In contrast to 2 however, no acyl ligand decarbonylation
was observed on reaction with dppm.
The reaction of 1 with dppm is in sharp contrast to
that reported for Ru2(CO)6(µ-PPh2){µ-η1,η2â,γ-C(Ph)d
CdCH2} in which the phosphido, allenyl, and carbonyl
groups couple together.8 In the latter case although the
intermediacy of an allenyl analogue Ru2(CO)4(µ-PPh2)-
(µ-dppm){µ-η1,η2-C(O)C(Ph)dCdCH2} of 2 in the forma-
tion of the final coupled product might be expected, this
was not verified spectroscopically. Clearly the nature
of the diphosphine influences the hapticity of the hydro-
carbyl fragment. The preference of dppe for a chelate
interaction with the metal in 3 is key in displacing the
allenyl from the η2-coordinated metal site and is likely
the result of steric crowding at Ru(2). The attachment
of the dppm ligand in 2 and 4 in a bridging position
facilitates bonding of the hydrocarbyl group to both
metal atoms.
temperatures. The 31P NMR spectrum is consistent
with the retention of a phosphido bridge and a bridging
diphosphine ligand.16 The structure (Figure 3)17 shows
an Ru2(CO)4(µ-PPh2)(µ-dppm) framework, similar to
that found in 2. In this case however, the acylallenyl
ligand has undergone elimination of one molecule of CO
to regenerate the µ-η1,η2R,â -allenyl ligand present in 1.
Thus the C3 fragment is σ-bound via C(5) to Ru(1)
(2.082(4) Å) and linked to Ru(2) via a π-interaction with
the CR-Câ double bond (Ru(2)-C(5) ) 2.344(3), Ru(2)-
C(6) ) 2.135(3) Å). The structural parameters of the
hydrocarbyl group are closely related to those found
in 1.10
Although CO insertion/elimination sequences are
commonplace for mononuclear σ-bonded organometal-
lics, this is the first example of such a stepwise trans-
formation on a binuclear allenyl complex. Acylallenyl
ligands of mononuclear platinum and palladium com-
plexes have been reported as intermediates in the prep-
aration of furanoylmetal compounds15a as well as during
the template synthesis of heterobimetallics from mono-
The present study illustrates the versatility of the
allenyl ligand and its adaptability in coordinating to
metal centers. Control over the hapticity of this C3
fragment may be achieved through judicious selection
of the ligand environment.
(16) Spectroscopic data for 4: IR (C6H12) ν(CO)/cm-1 2024 w, 2010
s, 1996 m; 1H NMR (CDCl3) δ 7.51-5.82 (m, 45H, Ph), 4.05 (m, 1H,
Ph2PCH2), 3.31 (m, 1H, Ph2PCH2); 31P{1H} NMR (CDCl3) δ 122.2 (dd,
Ack n ow led gm en t. We gratefully acknowledge sup-
port from the Natural Sciences and Engineering Re-
search Council (NSERC) and the National Research
Council of Canada (to A.J .C.) and the EPSRC for
funding for a diffractometer (to W.C.).
J PµP
) 37.0 Hz, J PµP
) 23.0 Hz, µ-P), 23.5 (dd, J P
) 92.0
dppm
dppmPdppm
) 92.0 Hz, J PµP
dppm
dppm
Hz, J PµP
) 23.0 Hz, dppm), 13.5 (dd, J P
)
dppmPdppm
37.0 Hzd,ppdmppm). Anal. Calc for C62H47O P3Ru2: C, 64.69; H, 4.12.
4
Found: C, 63.98; H, 4.22.
(17) Crystal data for 4‚C6H6: C68H53O4P3Ru2, M ) 1229.2; mono-
clinic, space group C2/c; a ) 40.684(6), b ) 12.305(2), c ) 23.972(3) Å;
â ) 102.90(2)°, V ) 11698(2) Å3, Z ) 8, T ) 294 K, Dc ) 1.396 g cm-3
,
Su p p or tin g In for m a tion Ava ila ble: For 2-4 details of
the structure determination (Tables S1, S6, and S11), non-
F(000) ) 5008, λ ) 0.710 73 Å, µ(Mo KR) ) 6.47 cm-1. Intensity data
were collected on a crystal of dimensions 0.78 × 0.56 × 0.68 × 0.92 ×
0.81 mm mounted on a Siemens R3m/V diffractometer by the ω scan
method (2θ < 50°). An absorption correction (face-indexed numerical)
was applied (transmission 0.665-0.730). Of 10 328 reflections mea-
sured, 8390 were considered observed [F > 6.0σ(F)]. The structure was
solved and refined as for 3, giving final R and Rw values (based on
Fo2) of 0.0316 and 0.0361 respectively.
(18) Wojcicki, A; Schuchart, C. E. Coord. Chem. Rev. 1990, 105, 35.
(19) (a) Schuchart, C. E.; Young, G. H.; Wojcicki, A.; Calligaris, M.;
Nardin, G. Organometallics 1990, 9, 2417. (b) Schuchart, C. E.;
Wojcicki, A.; Calligaris, M.; Faleschini, P.; Nardin, G. Organometallics
1994, 13, 1999.

300 Organometallics, Vol. 16, No. 3, 1997
Communications
hydrogen atomic positional and U parameters (Tables S2, S7,
and S12), bond distances and angles (Tables S3, S8, and S13),
anisotropic displacement parameters (Tables S4, S9, and S14),
and hydrogen atom parameters (Tables S5, S10, and S15) (34
pages). Ordering information is given on any current mast-
head page. Observed and calculated structure factor tables
are available from the authors upon request.
OM9607208