A half-sandwich perfluoroorganoytterbium(II) complex from a simple redox transmetalation/ligand exchange synthesis

Article abstract of DOI:10.1021/om021039a

The unique, half-sandwich perfluoroaryl-ytterbium(II) complex [Yb(C₅Me₅)(C₆F₅)(THF)₃ ] (1) was synthesized in one step from Yb metal, HgPh(C₆F₅) and HC₅Me₅. A report on the successful synthesis and structure of the half-sandwich organoytterbium(II) complex by redox-transmetalation/ligand-exchange reaction is presented. Extrapolation to a wide range of novel organolanthanoid(II) complexes is envisaged.

Full text of DOI:10.1021/om021039a

© Copyright 2003
Volume 22, Number 7, March 31, 2003
American Chemical Society
Communications
A Ha lf-Sa n d w ich P er flu or oor ga n oytter biu m (II) Com p lex
fr om a Sim p le Red ox Tr a n sm eta la tion /Liga n d Exch a n ge
Syn th esis
Glen B. Deacon* and Craig M. Forsyth
School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
Received December 26, 2002
Summary: Reaction of ytterbium metal with HgPh(C6F5)
and HC5Me5 in THF (THF ) tetrahydrofuran) affords
seven-coordinate, monomeric [Yb(C5Me5)(C6F5)(THF)3]
(1), which is presumed to be formed by protolysis of a
transitory “YbPh(C6F5)” species with HC5Me5. In the
absence of the latter, reaction of ytterbium metal and
HgPh(C6F5) gave a mixture of products, including the
structurally characterized [Yb(C6F5)2(THF)4] (2) and the
ytterbium(III) complex [YbPh3(THF)3] (3).
(L)R (L ) HB(3-But-5-Me-pz)3), complexes,4 stabilized
by a very bulky tris(pyrazolyl)borate ligand. While
metathetical precursors to Ln(C5R5)R exist (e.g. [Ln(C5-
Me5)I(THF)2]2; Ln ) Sm, Yb),5,6 the synthesis of these
potentially highly reactive species would benefit from
a simple one-step route. We now report the successful
synthesis and structure of the half-sandwich organoyt-
terbium(II) complex [Yb(C5Me5)(C6F5)(THF)3] by a new
redox-transmetalation/ligand-exchange reaction.
Ytterbium powder reacted with a mixture of HgPh-
(C6F5) and HC5Me5 in THF at room temperature and
gave red-orange [Yb(C5Me5)(C6F5)(THF)3] (1) in moder-
ate yield (eq 1).7 Crystalline 1 was characterized by Yb
The organometallic chemistry of the lanthanoid ele-
ments in the less common II oxidation state is domi-
nated by symmetrical LnR2 species. In particular, those
with π-bound carbocyclic C5R5 ligands have been ex-
tensively studied for their remarkable structures, redox
chemistry, and Lewis acid behavior.1 Much less is
known of the half-sandwich complexes Ln(C5R5)X (X )
halide, organoamide, organooxide),2 and there is only
one example of a structurally characterized organo-
metallic derivative, viz. [Eu(C5Me5)(µ-CCPh)(THF)2]2.3
By comparison with Ln(C5Me5)2 species, the presence
of a Ln-C σ-bond in Ln(C5Me5)R (R ) alkyl, aryl) adds
new dimensions to their potential reaction chemistry:
e.g., small-molecule insertion and σ-bond metathesis.
The latter has recently been exploited for analogous Ln-
Yb + HgPh(C6F5) + HC5Me5 THF8 1 + Hg + PhH
(1)
analysis, IR and NMR spectroscopy, and a single-crystal
X-ray structure determination (see below). The presence
of THF and the C6F5 groups was clearly evident in the
IR spectrum of 1 (ν(C-O) 1023, 875 cm-1; ν(C-F) 1072,
924 cm-1), while the 19F NMR spectrum showed reso-
nances apparently attributable to a single C6F5 environ-
ment but with a slight asymmetry of the o-F resonance
(1) Evans, W. J . Coord. Chem. Rev. 2000, 207, 263. For a review of
noncyclopentadienyl organolanthanoid(II) chemistry: Edelmann, F. T.;
Freckmann, D. M. M.; Schumann, H. Chem. Rev. 2002, 102, 1851.
(2) Hou, Z.; Wakatsuki, Y. J . Organomet. Chem. 2002, 647, 61.
(3) Boncella, J . M.; Tilley, T. D.; Andersen, R. A. J . Chem. Soc.,
Chem. Commun. 1984, 710.
(4) Takats, J . J . Organomet. Chem. 2002, 647, 84.
(5) Evans, W. J .; Grate, J . W.; Choi, H. W.; Bloom, I.; Hunter, W.
E.; Atwood, J . L. J . Am. Chem. Soc. 1985, 107, 941.
(6) Constantine, S. P.; De Lima, G. M.; Hitchcock, P. B.; Keates, J .
M.; Lawless, G. A. Chem. Commun. 1996, 2421.
10.1021/om021039a CCC: $25.00 © 2003 American Chemical Society
Publication on Web 03/05/2003

1350 Organometallics, Vol. 22, No. 7, 2003
Communications
Ta ble 1. 171Yb NMR Da ta for Yb(II) Ar yl a n d
Iod id e Com p lexes
compd
CN
δ(171Yb) (ppm)
ref
[Yb(C5Me5)2(THF)2]
[Yb(C5Me5)(C6F5)(THF)3]
[Yb(C5Me5)(I)(THF)2]2
[Yb(C6F5)2(THF)4]
[Yb(I)2(THF)4]
8
7
7
6
6
5
4
0
254
250
463
456
667
927
10
this work
6
this work
6
23
23
[Yb(Dpp)(I)(THF)3]a
[Yb(Dpp)2(THF)2]
a
Dpp ) 2,6-Ph2C6H3.
at high resolution (see below). The chemical shift values
are almost identical with those reported for Yb(C6F5)2
in THF.9 The 171Yb NMR data were particularly diag-
nostic, with the chemical shift of 1 in THF lying between
10
those of Yb(C5Me5)2 and Yb(C6F5)2 (Table 1). Indeed,
the value is very similar to that of the analogous
organoytterbium(II) iodide species6 (Table 1), consistent
with the pseudo-halide nature of C6F5-. THF solutions
of 1 were stable for approximately 24 h at room
temperature, and the isolated product could be stored
for several weeks at -20 °C. However, in nonpolar
solvents, rapid decomposition of 1 was observed, pre-
cluding workup and spectroscopic measurements in
these media. Decomposition was accompanied by the
formation of complex fluoroaromatic species (as detected
by 19F NMR) and suggests fluoride abstraction by the
ytterbium(II) center as the dominant pathway, similar
to that proposed for Yb(C6F5)2.9,11
F igu r e 1. Molecular structure of [Yb(C5Me5)(C6F5)(THF)3]
(1) with 50% thermal ellipsoids and hydrogen atoms
omitted for clarity.
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for [Yb(C5Me5)(C6F 5)(THF )3]
The structure12 of 1 is shown in Figure 1, and
pertinent bond distances and angles are listed in Table
2. The complex is monomeric, with the ytterbium atom
bound to a η5-C5Me5 group, C6F5, and three coordinated
THF ligands. This arrangement is in contrast with that
in dimeric [Ln(C5Me5)(µ-I)(THF)2]2 (Ln ) Sm,5 Yb6) and
[Eu(C5Me5)(µ-CCPh)(THF)2]23 and may reflect the poorer
bridging capacity of the C6F5 anion, owing to delocal-
ization of electron density from the ipso carbon by the
inductively electron-withdrawing fluorine substituents.
Yb(1)-C(7)
Yb(1)-C(8)
Yb(1)-C(9)
Yb(1)-C(10)
Yb(1)-C(11)
2.694(5)
2.664(5)
2.699(5)
2.744(5)
2.744(5)
Yb(1)-C(1)
Yb(1)-O(1)
Yb(1)-O(2)
Yb(1)-O(3)
Yb(1)-Cp
2.597(5)
2.456(4)
2.445(3)
2.489(4)
2.430
Yb(1)‚‚‚F(6)
3.162(4)
O(1)-Yb(1)-Cpa
O(2)-Yb(1)-Cp
O(3)-Yb(1)-Cp
C(1)-Yb(1)-Cp
C(1)-Yb(1)-O(1)
C(1)-Yb(1)-O(2)
C(1)-Yb(1)-O(3)
104.6
117.6
111.3
122.3
84.3(1)
120.1(2)
80.4(1)
O(1)-Yb(1)-O(2)
O(1)-Yb(1)-O(3)
O(2)-Yb(1)-O(3)
Cp-Yb(1)‚‚‚F(6)
Yb(1)-C(1)-C(2)
Yb(1)-C(1)-C(6)
82.7(1)
143.9(1)
77.2(1)
161.8
137.5(4)
109.9(4)
(7) 1: a mixture of Yb metal filings (1.4 g, 8.0 mmol), HgPh(C6F5)8
(2.2 g, 5.0 mmol), and HC5Me5 (0.68 g, 5.0 mmol) was stirred in THF
(60 mL) at room temperature for 6 h. After filtration and reduction of
the volume to 10 mL, the red-orange solution was treated with hexanes
(30 mL) and cooled to -20 °C. Red-orange crystals of 1 deposited
overnight (1.41 g, 41%). IR (Nujol): 1628 w, 1595 w, 1494 m (sh), 1416
s, 1297 w, 1222 w, 1173 w, 1072 m, 1039 vs, 1023 vs, 924 s, 875 m
a
Cp ) calculated centroid of C(7)-C(11).
Both the iodide and phenylethynyl complexes have the
same coordination number as 1, whereas analogous
half-sandwich complexes [Yb(C5Me5)(L)(THF)2] (L )
Si(SiMe3)3, N(SiMe3)2) with very bulky trimethysilyl-
substituted ligands are monomeric but six-coordi-
nate.13,14 The geometry around the Yb atom in 1 can be
described as a pseudo-square-based pyramid with the
centroid of the C5Me5 ring occupying the axial position.
The range of π-Yb-C(C5Me5) distances is comparable
with that of [Yb(C5Me5)(µ-I)(THF)2]2 (2.664(5)-
2.744(5) Å).6 However, the σ-Yb-C(C6F5) bond (Table
2) is significantly shorter (0.225 Å) than that (2.822(3)
Å) of the only earlier crystallographically characterized
Ln-C6F5 complex, [Eu(C6F5)2(THF)5],15 and the differ-
ence is almost twice that between the respective ionic
radii (ca. 0.12 Å).16 This suggests a degree of steric
cm-1 1H NMR (THF-d8): δ 1.96 (s, 15H, C5Me5). 19F NMR (THF-d8):
.
-109.8 (m, 2F, F2, 6), -162.4 (m, 2F, F3,5), -162.9 (m, 1F, F4). Anal.
Calcd for C28H39F5O3Yb: Yb, 25.1. Found: Yb, 24.9. Solid 1 decomposed
to an intractable black material after 1-2 days at room temperature
but could be stored at -20 °C for several weeks without significant
deterioration.
(8) Albrecht, H. B.; Deacon, G. B.; Tailby, M. J . J . Organomet. Chem.
1974, 70, 313.
(9) (a) Deacon, G. B.; Vince, D. G. J . Organomet. Chem. 1976, 112,
C1. (b) Deacon, G. B.; Raverty, W. D.; Vince, D. G. J . Organomet. Chem.
1977, 135, 103.
(10) Avent, A. G.; Edelmann, M. A.; Lappert, M. F.; Lawless, G. A.
J . Am. Chem. Soc. 1989, 111, 3423.
(11) Deacon, G. B.; Koplick, A. J .; Raverty, W. D.; Vince, D. G. J .
Organomet. Chem. 1979, 182, 121.
(12) Data were collected on an Enraf-Nonius CCD diffractometer
(λ ) 0.710 73 Å) at 123 K. Crystal data for
C28H39F5O3Yb (1):
Mr ) 691.63, monoclinic, space group P21/n, with cell dimensions a )
9.1980(2) Å, b ) 25.2911(5) Å, c ) 12.3206(3) Å, â ) 95.052(1)° and V
) 2855(1) Å3 with Dcalcd ) 1.609 g/cm3 (Z ) 4). R ) 4.29% and Rw
)
8.47% (4419 data with I >2σ(I); R ) 9.26% and Rw ) 9.58% for all
data). The structure was solved by conventional heavy-atom methods
and refined by full-matrix least squares on F2 (29 095 total and 6998
unique data, Rint ) 9.3%) with anisotropic thermal parameters for the
non-hydrogen atoms. Hydrogen atoms were placed in calculated
positions using a riding model.
(13) Corradi, M. M.; Frankland, A. D.; Hitchcock, P. B.; Lappert,
M. F.; Lawless, G. A. Chem. Commun. 1996, 2323.
(14) Evans, W. J .; J ohnston, M. A.; Clark, R. D.; Anwander, R.;
Ziller, J . W. Polyhedron 2001, 20, 2483.
(15) Forsyth, C. M.; Deacon, G. B. Organometallics 2000, 19, 1205.
(16) Shannon, R. D. Acta Crystallogr., Sect. A 1976, 32, 751.

Communications
Organometallics, Vol. 22, No. 7, 2003 1351
unsaturation in 1. The plane of the C6F5 group is
approximately perpendicular to that of the C5Me5 ring
carbon atoms (interplanar angle 72.6(2)°), and this
arrangement places one of the o-F substituents, F(6),
in a hole in the coordination sphere below the basal
plane (Cp-Yb(1)‚‚‚F(6) ) 161.8°). While the Yb(1)‚‚‚F(6)
separation (3.162(4) Å) is long compared with reported
dative LnIII‚‚‚F interactions of ∼2.55-2.90 Å17 (cf.
EuII‚‚‚F ) 3.006(6) Å in [Eu(µ-SC6F5)2(THF)2]n17b), the
fact that the Yb(1)-C(1)-C(6) angle is considerably
more acute than Yb(1)-C(1)-C(2) (Table 2) suggests at
least a weak contact. However, the positioning of the
C6F5 group is presumably also influenced by competitive
ligand-ligand repulsions (i.e. C6F5-THF vs C6F5-C5-
Me5). In any case, the location of F(6) would block the
coordination of a further THF ligand to the ytterbium
center. There is evidence that some Yb‚‚‚o-F bonding
persists in solution. Variable-temperature (+30 to -60
°C) 19F NMR spectroscopy resolves two o-F resonances
(108.9 and 109.6 ppm; integration 3F:1F) at 15 °C,
representing resolution of the asymmetry in the room-
temperature spectrum. We suggest that there are ap-
proximately equimolar amounts of two species, one with
the solid-state structure and one with uncoordinated
(freely rotating) C6F5 (possibly as a result of further
THF coordination). There is no splitting or asymmetry
of the other 19F resonances on cooling, and similarly,
the 1H methyl (C5Me5) and 171Yb resonances are narrow
and symmetrical; hence, the two species present must
be very similar in structure, consistent with the very
small separation of the two o-F resonances.
The formation of 1 from eq 1 is consistent with
previous observations that HC5Me5 does not exchange
with Yb(C6F5)2 but successfully displaces Ph, giving [Yb-
(C5Me5)2(THF)2] in reactions with Yb/HgPh2 (presum-
ably initially yielding YbPh2).18 The pKa value (calcu-
lated for THF19a from refs 19b,c) of HC5Me5 (26.2) is
similar to that of C6F5H (25.6) but much lower than for
PhH (42.5), favoring exchange with Yb-Ph but not Yb-
C6F5 moieties. This supports the proposal that the initial
product from eq 1 is the unsymmetrical YbII diaryl
species YbPh(C6F5) (eq 2), which then undergoes pref-
erential protolytic ligand exchange (eq 3). In an attempt
F igu r e 2. Molecular structure of [Yb(C6F5)2(THF)4] (2)
with 50% thermal ellipsoids and hydrogen atoms omitted
for clarity.
(THF)4].9 More significantly, only one 171Yb NMR reso-
nance (δ 459 ppm) was observed between -100 and
+1300 ppm and the chemical shift value was close to
that of [Yb(C6F5)2(THF)4] (Table 1). An attempted
crystallization of the putative “YbPh(C6F5)” complex by
cooling a concentrated THF/hexanes solution to -20 °C
gave an unidentified dark brown powder mixed with
orange crystals, which were shown to be [Yb(C6F5)2-
(THF)4] (2) (Figure 2) by X-ray crystallography (see
below). However, crystallization from THF only depos-
ited a small amount of yellow crystals of the YbIII
complex fac-[YbPh3(THF)3] (3).20 The X-ray structure21
of 3 shows that it has the same structure as the
previously reported Tm and Er analogues.22 While the
presence of 3 would be undetected by the NMR experi-
ments above owing to paramagnetism, its isolation and
Yb + HgPh(C6F5) THF8 “YbPh(C6F5)” + Hg (2)
YbPh(C6F5) + HC5Me5 THF8
Yb(C5Me5)(C6F5) + PhH (3)
to isolate (as a THF complex) or characterize YbPh-
(C6F5), the reaction of Yb powder with HgPh(C6F5) in
THF at room temperature in the absence of HC5Me5 was
studied.20 This gave a brown-orange solution, and the
19F NMR spectrum showed a single C6F5 environment,
very similar to the spectra of both 1 and [Yb(C6F5)2-
(20) A mixture of Yb metal (1.4 g, 8.0 mmol) and HgPh(C6F5) (2.22
g, 5.0 mmol) was stirred in THF (60 mL) at room temperature for 6 h.
After filtration, a portion (∼2-3 mL) of the brown-orange solution was
removed and examined by 19F and 171Yb NMR spectroscopy. The
remaining solution was concentrated and hexanes added. Cooling to
-20 °C overnight deposited orange crystals of 2, some of which were
hand-picked for crystallographic examination, mixed with a tacky
brown powder. From a separate preparation, the initial filtrate was
concentrated and cooled to -20 °C. Bright yellow crystals of 3 deposited
after several days (0.13 g, 13%). IR (Nujol): 3031 w, 1560 w, 1410 m,
1226 m, 1188 w, 1051 m, 1020 s, 987 w, 914 w, 867 s br, 718 m, 706
s, 673 w, 630 m cm-1. The sample partly decomposed during weighing
(17) (a) Melman, J . H.; Rohde, C.; Emge, T. J .; Brennan, J . G. Inorg.
Chem. 2002, 41, 28. (b) Melman, J . H.; Emge, T. J .; Brennan, J . G.
Inorg. Chem. 2001, 40, 1078. (c) Click, D. R.; Scott, B. L.; Watkin, J .
G. J . Chem. Soc., Chem. Commun. 1999, 633.
(18) Deacon, G. B.; Forsyth, C. M.; Nickel, S. J . Organomet. Chem.
2002, 647, 50.
(19) (a) Streitwieser, A.; Bors, D. A.; Kaufman, M. J . J . Chem. Soc.,
Chem. Commun. 1983, 1394. (b) Bordwell, F. G.; Bausch, M. J . J . Am.
Chem. Soc. 1983, 105, 6188. (c) Streitwieser, A.; Scannon, P. J .;
Niemeyer, H. M. J . Am. Chem. Soc. 1972, 94, 7936.
for microanalysis. Anal. Calcd for
Found: C, 55.5; H, 6.1.
C30H39O3Yb: C, 58.1; H, 6.3.

1352 Organometallics, Vol. 22, No. 7, 2003
Communications
C6F5 groups are rotated ∼65° to each other,15 and
presumably C6F5-THF repulsions are the dominant
influence. The Ln-σ-C distances of 2 (Table 3) and the
larger Eu analogue [Eu(C6F5)2(THF)5] (2.822(3) Å)15 are
comparable, after accounting for the difference in the
appropriate ionic radii (0.18 Å),16 but the value for 2 is
greater (ca. 0.1 Å) than that of 1 above. In contrast,
estimations of steric crowding in 1, 2, and [Eu(C6F5)2-
(THF)5] from comparison of ligand steric coordination
number26 summations (7.4 for 1, 7.4 for 2, and 8.6 for
[Eu(C6F5)2(THF)5], assuming C6F5 ≈ Ph in bulkiness)
suggest that the Ln-C bond lengths of 1 and 2 should
be similar, with that of [Eu(C6F5)2(THF)5] much longer.
Thus, the Ln-C bonding in 2 and [Eu(C6F5)2(THF)5]
appear influenced largely by the trans disposition of the
C6F5 anions, which may exhibit a repulsive trans
influence (see ref 27 for trans influences in lanthanoid
complexes).
In this contribution we have demonstrated that the
unique, half-sandwich perfluoroaryl-ytterbium(II) com-
plex [Yb(C5Me5)(C6F5)(THF)3] (1) can be successfully
synthesized in one step from Yb metal, HgPh(C6F5), and
HC5Me5. Analogous metal-based syntheses provide com-
petitive, halide- and alkali-metal-free, preparative routes
to a wide variety of Ln(L)n (n ) 2, 3) compounds,18,28
but this is the first application leading to a complex with
disparate ligands. The simplicity of the reaction and
ready availability of unsymmetrical HgPhR compounds29
potentially make this a highly versatile and attractive
synthetic method. Extrapolation to a wide range of novel
organolanthanoid(II) complexes is envisaged. The reac-
tivity of 1 toward both oxidative and protolytic sub-
strates is currently under investigation. Two new
structures of lanthanoid-fluorocarbon complexes add
to the understanding of the nature of polyfluorophenyl-
lanthanoid bonding, as there is only one such previous
structure,15 and 1 has the first organometallic lantha-
noid agostic F interaction.
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for [Yb(C6F 5)2(THF )4]a
Yb(1)-C(1)
Yb(1)-O(2)
2.649(3)
2.440(2)
Yb(1)-O(1)
2.428(2)
C(1)-Yb(1)-C(1i) 180.0
O(1)-Yb(1)-O(2)
98.44(8)
C(1)-Yb(1)-O(1)
C(1)-Yb(1)-O(1i)
C(1)-Yb(1)-O(2)
C(1)-Yb(1)-O(2i)
88.6(1)
91.4(1)
O(1)-Yb(1)-O(1i) 180.0
O(1)-Yb(1)-O(2i)
81.56(8)
87.54(9) O(2)-Yb(1)-O(2i) 180.0
92.46(9)
a
Symmetry transformation: (i) -x + 1, -y + 1, -z + 1.
that of 2 confirm the occurrence of a ligand redistribu-
tion process (eq 4) similar to that observed for the bulky
YbPh(C6F5) THF8 YbPh2 + Yb(C6F5)2
(4)
YbII aryl halides [Yb(Dpp)I(THF)3] (Dpp ) 2,6-Ph2C6H3).23
However, in the presence of HC5Me5, rapid ligand
exchange with the transitory YbPh(C6F5) species (eq 3)
enables the isolation of 1. The failure to observe YbPh2
by 171Yb NMR and the subsequent isolation of trivalent
3 suggests rapid oxidation of the YbPh2 complex, and
it is noteworthy that a well-defined YbPh2 complex has
not yet been isolated (cf. mixed-valent [YbIIIPh2(THF)(µ-
Ph)3YbII(THF)3]24).
Despite being been known for more than 20 years,9 2
is one of a very limited class of divalent organolantha-
noids devoid of cyclopentadienyl ligands and we have
now determined its molecular structure (Figure 2) for
the first time,21 only the third structure of a LnII
diaryl.15,23 Many previous attempts to collect X-ray data
for 2 were thwarted by very poor diffraction (due to
extensive twinning) of visually excellent crystals, com-
pounded by the extreme air and thermal instability of
the sample. Selected bond distances and angles for 2
are listed in Table 3. Monomeric 2 has a six-coordinate
Yb surrounded by two trans-C6F5 ligands with four
equatorial THF ligands completing an octahedral coor-
dination geometry, analogous to that of [YbI2(THF)4]25
as predicted earlier.15 Intriguingly, the two C6F5 groups
are coplanar, whereas in [Eu(C6F5)2(THF)5] the trans
Ack n ow led gm en t. We thank the Australian Re-
search Council for support.
Su p p or tin g In for m a tion Ava ila ble: X-ray crystallo-
graphic data for [Yb(C5Me5)(C6F5)(THF)3], [Yb(C6F5)2(THF)4],
and [YbPh3(THF)3]. This material is available free of charge
via the Internet at http://pubs.acs.org. Crystallographic data
have also been deposited with the Cambridge Crystallographic
Data Centre. Copies of this information may be obtained free
of charge from the CCDC, 12 Union Rd, Cambridge CB2 1EZ,
U.K. (fax +44 1223 336033; e-mail, deposit@cam.ac.uk or
http://www.ccdc.cam.ac.uk).
(21) Data were collected on an Enraf-Nonius CCD diffractometer
(λ ) 0.710 73 Å) at 123 K. Crystal data for C28H32F10O4Yb (2): Mr
)
795.58, monoclinic, space group P21/c, with cell dimensions a ) 9.3175-
(2) Å, b ) 18.9505(3) Å, c ) 8.3634(1) Å, â ) 98.151(1)°, and V ) 1461.8-
(5) Å3 with Dcalcd ) 1.807 g/cm3 (Z ) 2). R ) 2.48% and Rw ) 5.65%
(2543 data with I > 2σ(I); R ) 5.19% and Rw ) 6.28% for all data).
Crystal data for C30H39O3Yb (3): Mr ) 620.65, monoclinic, space group
C2/c, with cell dimensions a ) 36.0443(8) Å, b ) 11.1995(2) Å, c )
13.9736(3) Å, â ) -103.369(2)°, and V ) 5510(1) Å3 with Dcalcd ) 1.496
g/cm3 (Z ) 8). R ) 4.40% and Rw ) 7.51% (4469 data with I > 2σ(I);
R ) 9.21% and Rw ) 8.63% for all data). The structures were solved
by conventional heavy-atom methods and refined by full-matrix least
squares on F 2 (2, 18 486 total and 3534 unique data, Rint ) 5.0%; 3,
32 605 total and 6714 unique data, Rint ) 12.6%) with anisotropic
thermal parameters for the non-hydrogen atoms. Hydrogen atoms were
placed in calculated positions using a riding model.
OM021039A
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