Insertion reaction of phenyl isocyanate into the Ln-C σ-bond of organolanthanide complexes: Synthesis, characterization, and crystal structures of {(C5H4CH3)2Ln[μ-η1 :η3-OC(R)NPh]}2 (Ln = Sm, Dy, Er, Ho; R = n-butyl, α-naphthyl)

Article abstract of DOI:10.1021/om010346y

Cp′₂LnR(THF) (Cp′ = C₅H₄CH₃) reacted with phenyl isocyanate to form the PhNCO insertion products [Cp′₂Ln(OC(R)NPh)]₂ [R = n-butyl, Ln = Sm (1), Dy (2), Er (3); R = α-naphthyl, Ln = Dy (4)]. It was found that an excess of PhNCO did not affect the nature of the final complexes, a single insertion only being observed and excess PhNCO forming a cyclotrimer (5). The reaction of Cp′HoCl₂(THF)₃ with BuⁿLi and subsequently with 2 equiv of PhNCO in THF gave Ho[(OC(Buⁿ)NPh)]₃ (6) and [Cp′₂Ho(OC(Buⁿ)NPh)]₂ (7), which can be rationalized by the rearrangement reaction of the di-insertion product Cp′Ho[OC(Buⁿ)-NPh]₂(THF)_x. The structures of 1, 4·THF, 5·THF and 7 were determined by X-ray diffraction, revealing an unusual bonding mode of the amido groups arising from the insertion of PhNCO into the Ln-C σ-bonds and that the O-C-N fragment of the OC(R)NPh ligand acts as both a bridging and side-on chelating group.

Full text of DOI:10.1021/om010346y

5700
Organometallics 2001, 20, 5700-5706
In ser tion Rea ction of P h en yl Isocya n a te in to th e Ln -C
σ-Bon d of Or ga n ola n th a n id e Com p lexes: Syn th esis,
Ch a r a cter iza tion , a n d Cr ysta l Str u ctu r es of
{(C5H4CH3)2Ln [µ-η1:η3-OC(R)NP h ]}2 (Ln ) Sm , Dy, Er , Ho;
R ) n -bu tyl, r-n a p h th yl)
Xi-geng Zhou,* Li-bei Zhang, Ming Zhu, Rui-fang Cai, and Lin-hong Weng
Department of Chemistry, Fudan University, Shanghai 200433, People’s Republic of China,
and State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences,
Shanghai 200032, People’s Republic of China
Zi-xiang Huang and Qiang-jin Wu
State Key Laboratory of Structural Chemistry, Fuzhou 350002, People’s Republic of China
Received April 30, 2001
Cp′2LnR(THF) (Cp′ ) C5H4CH3) reacted with phenyl isocyanate to form the PhNCO
insertion products [Cp′2Ln(OC(R)NPh)]2 [R ) n-butyl, Ln ) Sm (1), Dy (2), Er (3); R )
R-naphthyl, Ln ) Dy (4)]. It was found that an excess of PhNCO did not affect the nature
of the final complexes, a single insertion only being observed and excess PhNCO forming a
cyclotrimer (5). The reaction of Cp′HoCl2(THF)3 with BunLi and subsequently with 2 equiv
of PhNCO in THF gave Ho[OC(Bun)NPh)]3 (6) and [Cp′2Ho(OC(Bun)NPh)]2 (7), which can
be rationalized by the rearrangement reaction of the di-insertion product Cp′Ho[OC(Bun)-
NPh]2(THF)x. The structures of 1, 4‚THF, 5‚THF and 7 were determined by X-ray diffraction,
revealing an unusual bonding mode of the amido groups arising from the insertion of PhNCO
into the Ln-C σ-bonds and that the O.C.N fragment of the OC(R)NPh ligand acts as
both a bridging and side-on chelating group.
In tr od u ction
Insertions of isocyanates into main group metal-
carbon and transition metal-carbon bonds have been
extensively studied. The accumulated information in
this field indicates that the occurrence of the insertion
strongly depends on the degree of steric saturation
around the central metal ion and the nature of the alkyl
ligands.5 However, there is essentially nothing known
about isocyanate insertion into Ln-C σ bonds.6,7 To
better understand the reactivity of organolanthanide
complexes toward isocyanates, in this paper we report
the synthesis, characterization, and crystal structures
of the insertion products obtained from the reaction of
phenyl isocyanate with organolanthanide alkyl (aryl)
complexes.
Organolanthanide alkyl (aryl) complexes continue to
attract considerable attention by virtue of the diverse
reactivities arising from the Ln-C σ-bond. These species
have been utilized as catalysts in a number of trans-
formations involving alkenes and imine and in stoichio-
metric reactions with organic functionality groups.1 In
sharp contrast to the extensive chemistry of bis(cyclo-
pentadienyl)lanthanide alkyl (aryl) complexes, very
little is known about the behavior of monocyclopenta-
dienyllanthanide dialkyls (or diaryls) due to ligand
redistribution in solution.2 On the other hand, although
organolanthanide alkyls and aryls are important inter-
mediates in homogeneous catalysis and organometallic
synthesis,3 little attention has focused on lanthanide
n-butyl derivatives due to the likelihood of â-hydrogen
elimination and therefore instability which leads to
difficulty in studying further reactivity.4
Resu lts a n d Discu ssion
Syn th esis a n d Ch a r a cter iza tion of P h NCO In -
ser tion P r od u cts [Cp ′2Ln OC(Bu n )NP h ]2 (Ln ) Sm ,
Dy, Er ). The reaction of Cp′2LnCl with BunLi and
(1) (a) Arredondo, V. M.; Tian, S.; McDonald, F. E.; Marks, T. J . J .
Am. Chem. Soc. 1999, 121, 3633. (b) Molander, G. A.; Retsch, W. H. J .
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(5) (a) Braunstein, P.; Nobel, D. Chem. Rev. 1989, 89, 1927. (b)
Koschmieder, S. U.; Wilkinson, G.; Hussain-Bates, B.; Hursthouse, M.
B. J . Chem. Soc., Dalton Trans. 1992, 19. (c) Forster, G. D.; Hogarth,
G. J . Chem. Soc., Dalton Trans. 1993, 2539. (d) Legzdins, P.; Phillips,
E. C.; Rettig, S. J .; Trotter, J .; Veltheer, J . E.; Yee, V. C. Organome-
tallics 1992, 11, 3104. (e) Paul, F.; Fischer, J .; Ochsenbein, P.; Osborn,
J . A. Angew. Chem., Int. Ed. Engl. 1993, 32, 1638.
(2) Cotton, S. A. Coord. Chem. Rev. 1997, 160, 93.
(3) (a) Heeres, H. J .; Meetsma, A.; Teuben, J . H. Organometallics
1990, 9, 1508. (b) Evans, W. J .; Wayda, A. L.; Hunter, W. E.; Atwood,
J . L. J . Chem. Soc., Chem. Commun. 1981, 706. (c) J eske, G.; Lauke,
H.; Mauermann, H.; Swepston, P. N.; Schumann, H.; Marks, T. J . J .
Am. Chem. Soc. 1985, 107, 8091.
(4) (a) Schumann, H.; Genthe, W.; Bruncks, N. Angew. Chem., Int.
Ed. Engl. 1981, 20, 119. (b) Watson, P. L.; Roe, D. C. J . Am. Chem.
Soc. 1982, 104, 6471. (c) Evans, W. J .; Wayda, A. L.; Hunter, W. E.;
Atwood, J . L. J . Chem. Soc., Chem. Commun. 1981, 292.
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1998, 120, 9273.
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10.1021/om010346y CCC: $20.00 © 2001 American Chemical Society
Publication on Web 11/29/2001

Insertion Reaction of Phenyl Isocyanate
Organometallics, Vol. 20, No. 26, 2001 5701
Sch em e 1
subsequently with phenyl isocyanate provided the di-
nuclear products [Cp′2LnOC(Bun)NPh]2 [Ln ) Sm (1),
Dy (2), Er (3)]. The formation of complexes 1-3 was
interpreted as an isocyanate molecule insertion into the
Ln-C σ-bond of the intermediate Cp′2LnBun(THF),4a as
shown in Scheme 1. It is noteworthy that for ytterbium
with the stronger reducibility, its analogue could not
be obtained in a similar manner. The reaction of Cp′2-
YbCl with BunLi, followed with PhNCO in THF, led to
a complex product mixture under the same conditions,
since Cp′2YbCl can be partially reduced to divalent Cp′2-
Yb by BunLi as observed in (C5H5)2YbCl.4c In addition,
no insertion of the Cp′-Ln bonds was observed at
ambient temperature in excess amount of PhNCO even
with a longer reaction time.
All the compounds were characterized by elemental
analyses and IR and MS spectral data, which were in
good agreement with the proposed structures. Com-
plexes 1-3 are moderately sensitive toward moisture
and air. They are soluble in THF, but less soluble in
n-hexane. In the mass spectra, all the compounds are
characterized by the loss of the Cp′ group from the
molecular ion with the [M - Cp′]+ ion as a strong peak.
In the IR spectral data of 1-3, the band is observed at
ca. 1570 cm-1, which may be assigned to the absorption
of the delocalized mode of the -O.C.N- unit of the
resulting amido ligand.8 The bonding mode was proven
by X-ray single-crystal diffraction on complex 1.
F igu r e 1. ORTEP diagram of [Cp′2SmOC(Bun)NPh]2 (1)
with the probability ellipsoids drawn at the 30% level.
Ta ble 1. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in 1a
Bond Distances
Sm(1)-O(1)
Sm(1)-O(1A)
Sm(1)-C(3)
Sm(1)-C(4)
Sm(1)-C(5)
Sm(1)-C(2)
Sm(1)-C(1)
O(1)-C(13)
N(1)-C(18)
2.374(3)
2.529(3)
2.710(5)
2.713(5)
2.738(5)
2.747(5)
2.769(5)
1.305(5)
1.413(5)
Sm(1)-N(1A)
Sm(1A)-C(13)
Sm(1)-C(10)
Sm(1)-C(9)
Sm(1)-C(11)
Sm(1)-C(8)
Sm(1)-C(7)
N(1)-C(13)
C(13)-C(14)
2.515(3)
2.938(4)
2.713(5)
2.725(5)
2.747(5)
2.759(5)
2.772(5)
1.296(5)
1.513(6)
Bond Angles
119.8(1) O(1)-Sm(1)-O(1A)
O(1)-Sm(1)-N(1A)
69.8(1)
N(1A)-Sm(1)-O(1A) 51.9(1) Sm(1)-O(1)-Sm(1A) 110.2(1)
C(13)-O(1)-Sm(1)
O(1)-C(13)-N(1)
N(1)-C(13)-C(14)
153.8(3) C(13)-O(1)-Sm(1A)
116.1(4) C(13)-N(1)-C(18)
124.8(4) O(1)-C(13)-C(14)
94.7(2)
123.5(3)
118.6(4)
a
Symmetry transformation (A): -x, 2-y, 2-z.
The crystal structure of complex 1 (Figure 1) reveals
a centrosymmetric dimer. Selected bond distances and
angles are compiled in Table 1. X-ray analysis shows
an unusual bonding mode of the OC(Bun)NPh ligand
and that the O.C.N fragment of the amido ligand acts
as both a bridging and side-on chelating group. Each
samarium atom is coordinated by two η5-C5H4CH3
groups, one chelating η3-OC(Bun)NPh ligand, and one
bridging oxygen atom from another OC(Bun)NPh ligand.
Both the O(1)-C(13) and the N(1)-C(13) distances of
1.305(5) and 1.296(5) Å lie between single- and double-
bond distances.9,10 This suggests some electronic delo-
calization over the O-C-N unit. Consistent with this,
the Sm(1)-N(1A) distance of 2.515(3) Å is slightly
shorter than the Smr:N donor bond,6,11 and there is a
weak interaction between Sm(1A) and C(13).12 The
delocalization is also verified by the fact that the Sm-
(1)-O(1A) distance of 2.529(3) Å is similar to the Sm-
(1)-N(1A) distance of 2.515(3) Å. The distances of
C(13)-C(14) and N(1)-C(18) correspond well to single
bonds. The bond angles around C(13) are consistent
with sp2 hybridization.
Significantly, it is different from the results observed
in [Cp2Ln(µ-OR)]2-type organolanthanide complexes,
where two bridging Ln-O distances are usually simi-
lar,13,19,23 that the Sm(1)-O(1) distance of 2.374(3) Å in
(13) (a) Steudel, A.; Stehr, J .; Siebel, E.; Fischer, R. D. J . Organomet.
Chem. 1998, 570, 89. (b) Evans, W. J .; Sollberger, M. S.; Shreeve, J .
L.; Olofson, J . M.; Hain, J . H.; Ziller, J . W. Inorg. Chem. 1992, 31,
2492. (c) Evans, W. J .; Dominguez, R. D.; Hanusa, T. P. Organome-
tallics 1986, 5, 1291. (d) Schumann, H.; Palamidis, E.; Loebel, J . J .
Organomet. Chem. 1990, 384, C49. (e) Zhou, X. G.; Ma, W. W.; Huang,
Z. E.; Cai, R. F.; You, X. Z.; Huang, X. Y. J . Organomet. Chem. 1997,
545-546, 309. (f) Zhou, X. G.; Ma, H. Z.; Huang, X. Y.; You, X. Z. J .
Chem. Soc., Chem. Commun. 1995, 2483. (g) Stults, S. D.; Anderson,
R. A.; Zalkin, A. Organometallics 1990, 9, 623.
(8) Wilkins, J . D. J . Organomet. Chem. 1974, 67, 269.
(9) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G. J . Chem. Soc., Perkin Trans. 1987, S1.
(10) Wu, Z. Z.; Zhou, X. G.; Zhang, W.; Xu, Z.; You, X. Z.; Huang, X.
Y. J . Chem. Soc., Chem. Commun. 1994, 813.
(11) Obora, Y.; Ohta, T.; Stern, C. L.; Marks, T. J . J . Am. Chem.
Soc. 1997, 119, 3745.
(12) Zhou, X. G.; Zhang, L. B.; Huang, Z. E.; Cai R. F.; Huang, X. Y.
Chin. J . Struct. Chem. 1999, 18, 373.
(14) (a) Wu, Z. Z.; Xu, Z.; You, X. Z.; Zhou, X. G.; Huang, X. Y.; Chen,
J . T. Polyhedron 1994, 13, 379. (b) Evans, W. J .; Ulibarri, T. A.;
Chamberlain, L. R. Ziller, J . W. Organometallics 1990, 9, 2124. (c)
Evans, W. J .; Grate, J . W.; Bloom, I.; Hunter, W. E.; Atwood, J . L. J .
Am. Chem. Soc. 1985, 107, 405. (d) Evans, W. J .; Foster, S. E. J .
Organomet. Chem. 1992, 433, 79.

5702 Organometallics, Vol. 20, No. 26, 2001
Zhou et al.
1 is significantly shorter than the Sm(1)-O(1A) distance
of 2.529(3) Å. The latter is within the 2.44(2)-2.64(2)
Å range of the Smr:OR2 bond for neutral oxygen donor
ligands.14 The Sm-O-Sm angle of 110.2(1)° is slightly
larger than those observed in other oxygen-bridging
complexes, 104.3(2)-108.3(1)°, but the O-Sm-O angle
of 69.8(1)° is smaller than the corresponding values,
71.7(1)-75.7(2)°.13,19,23 These may be attributed to the
steric effect caused by the side-on chelating coordination
of Sm3+ to the O.C.N fragment of the amido group.
It is noteworthy that when the differences in the ionic
radii are considered,15 the chelating Sm-O and Sm-N
distances are compatible with the corresponding values
in Cp2ZrMe[OC(Me)NPh], 2.298(4) and 2.297(4) Å.16
The average Sm-C(η5-Cp′) distance of 2.736(5) Å is
similar to those found in other trivalent samarium
complexes, such as [(C5H4Me)2(THF)Sm(µ-Cl)]2, 2.72(3)
Å;17 Cp3Sm(THF), 2.75(2) Å;14a and (OCH2CH2CH2CH-
CH2C5H4)2SmCl, 2.721(7) Å.18 The Sm(1A)-C(13) dis-
tance of 2.938(4) Å is longer than the average Sm-C(η5-
Cp′) distance, indicating a weak interaction between
Sm(1A) and C(13).12
Syn th esis a n d Ch a r a cter iza tion of [Cp ′2Dy(OC-
(Np )NP h )]2 (4). To understand the factors affecting the
insertion of isocyanate into the lanthanide-carbon
bond, the reaction of isocyanate with rare earth aryl
complex Cp′2DyNp (Np ) R-naphthyl) was also studied,
which provided the corresponding insertion product
[Cp′2Dy(OC(Np)NPh)]2, indicating the occurrence of the
insertion is less affected by the properties of the alkyl
ligands. In addition, it was found that a large excess of
PhNCO did not affect the nature of the final compound,
a single insertion only being observed.
Complex 4 is moderately sensitive toward moisture
and air. It is soluble in THF, but less soluble in
n-hexane. Figure 2 shows the molecular structure of 4.
Selected bond distances and angles are listed in Table
2. Each dysprosium atom carries two η5-methylcyclo-
pentadienyl groups and is chelated by one of the amido
ligands, the oxygen atom of which then bridges over to
another Dy atom. The Dy-C(Cp′) distances range from
2.59(4) to 2.77(3) Å and average 2.67(4) Å. The average
value is similar to those found in other Cp2Dy-contain-
ing compounds, such as [Cp2Dy(OCMedCHCH3)]2, 2.67-
(1) Å.19 The chelating Dy-O distance of 2.481(13) Å is
larger than the bridging Dy-O distance of 2.357(13) Å.
The Dy-N(1), Dy-O(1), and Dy-C(13) distances of
2.483(14), 2.481(13), and 2.916(15) Å are slightly longer
than the corresponding distances in 1, respectively,
F igu r e 2. ORTEP diagram of [Cp′2DyOC(Np)NPh]2 (4)
with the probability ellipsoids drawn at the 30% level.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in 4a
Bond Distances
Dy-O(1A)
Dy-O(1)
Dy-C(11)
Dy-C(2)
2.357(13)
2.481(13)
2.59(4)
2.67(3)
2.67(3)
2.68(4)
2.71(3)
1.30 (2)
1.46(2)
Dy-N(1)
Dy-C(13)
Dy-C(10)
Dy-C(1)
2.483(15)
2.916(4)
2.61(3)
2.67(3)
2.67(4)
2.71(3)
2.77(3)
1.25(2)
1.49(3)
Dy-C(3)
Dy-C(7)
Dy-C(9)
Dy-C(8)
O(1)-C(13)
N(1)-C(18)
Dy-C(4)
Dy-C(5)
N(1)-C(13)
C(13)-C(20)
Bond Angles
O(1A)-Dy-N(1)
N(1)-Dy-O(1)
C(13)-O(1)-Dy
O(1)-C(13)-N(1)
119.4(5)
51.5(5)
O(1)-Dy-O(1A)
67.9(5)
111.0(5)
Dy-O(1)-Dy(A)
95.8(13) C(13)-O(1)-Dy(A) 148.6(15)
115.1(19) C(13)-N(1)-C(14) 124.5(18)
N(1)-C(13)-C(20) 124.8(18) O(1)-C(13)-C(20) 119.5(19)
a
Symmetry transformation (A): 1-x, -y, z.
when the differences in the ionic radii are considered.15
This shows that the tendency toward a η3-fashion
coordination for the OC(R)NPh group is to decrease
when the steric crowding increases.
Cyclop olym er iza tion of P h en yl Isocya n a te Ca ta -
lyzed by Com p lex 2. In contrast to the reaction of (C5-
Me5)3Sm, where a second equivalent of phenyl isocyan-
ate can be incorporated into the first insertion product
to form (C5Me5)2Sm[OC(C5Me5)N(Ph)C(NPh)O],6 we
have found that only observable products are complex
2 and cyclotrimer (PhNCO)3 (5) in the reaction of 2 and
excess phenyl isocyanate or when Cp′2LnBun(THF)
reacted with excess phenyl isocyanate. This might be
attributed to the difference of the steric crowding of the
center metal in the two cases. For the more sterically
(15) Shannon, R. D. Acta Crystallogr. 1976, A32, 751.
(16) Gambarotta, S.; Strologo, S.; Floriani, C.; Chiesi-Villa, A.;
Guastini, C. Inorg. Chem. 1985, 24, 654.
(17) Evans, W. J .; Keyer, R. A.; Ziller, J . W. J . Organomet. Chem.
1993, 450, 115.
(18) Zhang, L. B.; Zhou, X. G.; Cai, R. F.; Weng, L. H. J . Organomet.
Chem. 2000, 612, 176.
(19) Wu, Z. Z.; Xu, Z.; You, X. Z.; Zhou, X. G.; Huang, X. Y. J .
Organomet. Chem. 1994, 483, 107.
(20) Chisholm, M. H.; Cotton, F. A.; Folting, K.; Huffman, J . C.;
Ratermann, A. L.; Shamshoum, E. S. Inorg. Chem. 1984, 23, 4423.
(21) Lai, R.; Mabille, S.; Croux, A.; Bot, S. L. Polyhedron 1991, 10,
463.
(22) (a) Wu, Z. Z.; Xu, Z.; You, X. Z.; Wang, H. J .; Zhou, X. G.
Polyhedron 1993, 12, 677. (b) Huang, X. Y.; Zhou, X. G.; Zhang, L. X.;
Feng, X. J .; Cai, R. F.; Huang, Z. E. Chin. J . Struct. Chem. 1998, 17,
449.
saturated (C5Me5)2Sm[OC(C5Me5)N(Ph)C(NPh)O] the
insertion of the third PhNCO molecule is prevented, so
a di-insertion product is isolated, while for the less
sterically demanding Cp′2Ln(OCNPh)2Bun the approach
of the third PhNCO to the metal center is less hindered,
(23) Zhou, X. G.; Huang, Z. E.; Cai, R. F.; Zhang, L. B.; Zhang, L.
X.; Huang, X. Y. Organometallics 1999, 18, 4128.

Insertion Reaction of Phenyl Isocyanate
Organometallics, Vol. 20, No. 26, 2001 5703
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in 5
Sch em e 2
Bond Distances
C(1)-O(1)
C(1)-N(3)
N(1)-C(4)
C(2)-N(2)
N(2)-C(10)
C(3)-N(3)
1.202(2)
1.389(2)
1.452(2)
1.389(2)
1.453(2)
1.392(2)
C(1)-N(1)
N(1)-C(2)
C(2)-O(2)
N(2)-C(3)
C(3)-O(3)
N(3)-C(16)
1.383(2)
1.390(2)
1.198(2)
1.387(2)
1.198(2)
1.449(2)
Cp′Ho(Bun)2(THF)n reacted with 2 equiv of phenyl
isocyanate, forming the di-insertion product Cp′Ho[OC-
(Bun)NPh]2(THF)x by the route we propose in Scheme
2. However, attempts to isolate the pure product were
unsuccessful. Cp′Ho[OC(Bun)NPh]2(THF)x is susceptible
to heat and decomposes easily to Ho[OC(Bun)NPh]3 (6)
and [Cp′2Ho(OC(Bun)NPh)]2 (7) in toluene at room
temperature. It is noteworthy that the above dispro-
portionation reaction of Cp′Ln[OC(Bun)NPh]2 is revers-
ible. The rate of this disproportionation increases con-
siderably at elevated temperature, but when the
temperature is below -20 °C, the rearrangement prod-
ucts are slowly transformed into the starting material.
Significantly, when an excess of PhNCO is used, a
cycloaddition product (5) and unidentified polymers of
some kinds were observed too.
Bond Angles
O(1)-C(1)-N(1)
N(1)-C(1)-N(3)
C(1)-N(1)-C(2)
N(2)-C(2)-N(1)
122.59(14) O(1)-C(1)-N(3)
115.13(13) C(1)-N(1)-C(4)
124.85(12) C(2)-N(1)-C(4)
115.04(12) C(3)-N(2)-C(2)
122.27(14)
117.34(12)
117.43(12)
124.83(12)
C(3)-N(2)-C(10) 118.00(12) C(2)-N(2)-C(10) 116.77(12)
N(2)-C(3)-N(3)
114.73(13) C(1)-N(3)-C(3)
124.86(13)
C(1)-N(3)-C(16) 117.41(12) C(3)-N(3)-C(16) 117.72(12)
It will be noted that PhNCO has inserted into all the
available Ln-C σ-bonds, although similar complete
insertion of RNCO has been observed in only a few
cases.5b For example, only one of the M-C σ-bonds is
reactive to isocyanate even under more drastic condi-
tions for Cp2ZrR2 (R ) Me, Ph, CH2Ph),16 MoO2(Mes)2,21
[Mn(CH2But)2]4,5b and [Mn(CH2CMe2Ph)2]2.5b In the
latter case the steric factors were proposed to mitigate
against coordination of a second organic isocyanate
molecule, thus preventing its insertion. The insertion
of a second PhNCO molecule into the Ln-C σ-bond may
be attributed to two favorable facts: (i) the presence of
a vacant coordination site at the bigger lanthanide
metal center satisfies the need of precoordination of the
PhNCO molecule preceding insertion; (ii) the stronger
ionic characteristics of the Ln-C σ-bond enhance the
migratory aptitude of the alkyl ligands. Consistent with
the scenario that substrate precoordination must occur
to access the intermediate is the fact that a large excess
of PhNCO cannot be catalyzed to polymerize by the
above transition-metal complexes.5b,6
F igu r e 3. ORTEP diagram of (PhNCO)3 (5) with the
probability ellipsoids drawn at the 30% level.
which should prevent the insertion from staying at the
1:2 adduct and catalyze the excess PhNCO to polymerize
cyanurates (PhNCO)3. Reactions of this type have
previously been observed in the insertion of isocyanate
into the M-O bond.20 It is noteworthy that the cyclo-
trimer reaction is readily complicated at room temper-
ature by some side reactions, so the reaction mixture
must be slowly warmed to room temperature. The IR
spectra of 5 appeared a strong band at 1708 cm-1, which
might be attributed to a CdO stretch.
The cyclotrimer 5 was proven by the X-ray analysis.
Selected bond distances and bond angles are compiled
in Table 3. It can be seen (Figure 3) that the molecule
structure of 5 confirms closely a six-membered ring
constitution, in which the three substrate molecules are
joined by the C-N coupling. The average carbon-
oxygen distance [1.199(2) Å] agrees well with the
corresponding formal CdO distances. The average car-
bon(ring)-nitrogen distance [1.388(2) Å] is in the middle
of the 1.321-1.416 Å range of C(sp2)-N distances.9 The
N(1), C(1), N(2), C(2), N(3) and C(3) atoms are coplanar
within experimental error.
Complexes 6 and 7 have been characterized by
standard spectroscopic and analytical techniques. Com-
plexes 6 and 7 have MS and IR spectra consistent with
their known or assumed structure. Complex 7 has been
structurally characterized by an X-ray analysis.
Table 4 lists the selected bond distances and bond
angles in 7. As depicted in Figure 4, the structure of 7
is well comparable to that of 1. The holmium molecule
resides on a crystallographic axis of 2-fold symmetry.
The two bridging PhNC(Bun)O ligands point in opposite
directions, and the two metal atoms are equivalent.
Each holmium ion is coordinated by two η5-Cp′ groups,
one chelating amido ligand, and one bridging O atom
of a second amido ligand. Bond lengths and angles in
the amido functions indicate also their bonding in an
µ-η1:η3-fashion. The bridging Ho2O2 unit is planar. The
coordination number of the holmium atom is 10. The
methylcyclopentadienyl groups on each holmium center
are arranged in an eclipsed conformation. The complex
has no unusual distances or angles in the Cp′2Ho unit.
The average Ho-C(ring) distance of 2.647(4) Å is in the
Rea ction of Mon ocyclop en ta d ien ylla n th a n id e
Dibu tyl w ith P h en yl Isocya n a te. To gain more
insight into the insertion of isocyanate into the Ln-C
σ-bond, the reaction of isocyanate with organolan-
thanide dialkyls was also studied. It was found that

5704 Organometallics, Vol. 20, No. 26, 2001
Zhou et al.
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) in 7a
and Cp′LnR2(THF)n under more mild conditions, but
also the reaction is less affected by the properties of the
R ligand. Moreover, in contrast to the trends of the
sterically encumbered compound Cp*3Sm, where a
second equivalent of substrate can be incorporated into
the first insertion product, in the present case, the
monoinsertion product catalyzed the excess of PhNCO
to form the cyclotrimer. All observed differences indicate
that the nature of the M-R bond and the steric
crowding around the central metal ion may have a much
greater influence on the insertion. Moreover, the X-ray
analyses have revealed an unusual bonding mode of the
amido groups arising from insertion of PhNCO into the
Ln-C σ-bonds and that the O.C.N fragment of the
OC(Bun)NPh ligand acts as both a bridging and side-
on chelating group.
Bond Distances
Ho(1)-O(1)
Ho(1)-O(1A)
Ho(1)-C(22)
Ho(1)-C(23)
Ho(1)-C(11)
Ho(1)-C(24)
Ho(1)-C(21)
O(1)-C(31)
N(1)-C(1)
2.442(3)
2.308(3)
2.633(4)
2.636(4)
2.642(4)
2.663(5)
2.684(5)
1.319(5)
1.430(5)
Ho(1)-N(1)
Ho(1)-C(31)
Ho(1)-C(12)
Ho(1)-C(13)
Ho(1)-C(14)
Ho(1)-C(15)
Ho(1)-C(25)
N(1)-C(31)
C(31)-C(32)
2.437(3)
2.884(4)
2.634(5)
2.638(4)
2.658(4)
2.683(4)
2.714 (5)
1.286(5)
1.506(5)
Bond Angles
O(1A)-Ho(1)-N(1) 119.2(1) O(1)-Ho(1)-O(1A)
67.4(1)
N(1)-Ho(1)-O(1)
C(31)-O(1)-Ho(1)
O(1)-C(31)-N(1)
N(1)-C(31)-C(32)
53.3(1) Ho(1)-O(1)-Ho(1A) 112.6(1)
95.5(2) C(31)-O(1)-Ho(1A) 149.7(3)
114.3(3) C(31)-N(1)-C(1)
128.0(4) O(1)-C(31)-C(32)
123.5(3)
117.5(4)
a
Symmetry transformation (A): -x, 1-y, -z.
Exp er im en ta l Section
Ma ter ia ls a n d Meth od s. All manipulations were carried
out under argon with rigorous exclusion of air and moisture
using Schlenk, vacuum-line, and glovebox techniques. All
solvents were refluxed and distilled over sodium benzophenone
ketyl immediately before use. Cp′HoCl2(THF)3,25 Cp′2LnCl
(Ln ) Sm, Dy, Er, Yb; Cp′ ) C5H4CH3),26 and Cp′2Ln(Bun)4a
were prepared by the literature procedures. The phenyl
isocyanate (Aldrich), R-bromonaphthalene (Fluka) and n-
butyllithium (Fluka) were used without further purification.
Elemental analyses for carbon, hydrogen and nitrogen were
performed on a Rapid CHN-O analyzer. Metal analyses for
lanthanides were accomplished using the literature method.27
Infrared spectra were obtained on a NICOLET FT-IR 360
spectrometer with samples prepared as Nujol mulls. Mass
spectra were recorded on a Philips HP5989A instrument
operating in EI mode. Crystal samples of the respective
complexes were rapidly introduced by the direct inlet tech-
niques with a source temperature of 200 °C. The values of m/z
1
are referred to the isotopes 12C, H, 14N, 152Sm, 164Dy, 165Ho,
and166Er.
[Cp ′2Sm OC(Bu n )NP h ]2 (1). To a solution of Cp′2SmCl-
(THF) (0.302 g, 0.725 mmol) in THF (30 mL) was added
n-butyllithium (1.24 M, in cyclohexane, 0.58 mL) at -30 °C.
After stirring for 4 h, to the mixture was added phenyl
isocyanate (0.08 mL, 0.725 mmol) at -10 °C. The reaction
mixture was then warmed to ambient temperature and stirred
overnight. The solvent was removed by reduced pressure. The
solid was extracted with toluene. The resulting yellow solution
was concentrated by reduced pressure to about 5 mL, and a
yellow solid precipitated. The precipitate was resolved by
addition of 2 mL of THF. Yellow crystals of 1 (0.26 g, 74%)
were obtained upon cooling at -30 °C, mp 174 °C. Anal. Calcd
for C46H56N2O2Sm2: C, 56.98; H, 5.82; N, 2.89; Sm, 31.01.
Found: C, 56.76; H, 5.73; N, 2.90; Sm, 30.67. IR (KBr pellet,
cm-1): 1664 m, 1568 m, 1556 m, 1463 s, 1377 s, 1330 m, 1277
w, 1232 w, 1093 w, 1045 w, 1026 m, 1012 m, 955 m, 820 m,
778 s, 754 s, 723 s, 699 m, 656 w, 619 w. MS: m/e [fragment,
relative intensity %] ) 893 [M - Cp′, 3], 814 [M - 2Cp′, 1],
716 [M - OC(Bun)NPh-Cp′H, 1], 486 [M/2, 2], 429 [M/2 - C3H6,
40], 407 [M/2 - Cp′, 100], 328 [M/2 - 2Cp′, 44], 310 [Cp′2Sm,
21], 231 [Cp′Sm, 24], 79 [Cp′, 20], 77 [Ph, 40], 57 [Bun, 4].
[Cp ′2DyOC(Bu n )NP h ]2 (2). To a solution of Cp′2DyCl (0.196
g, 0.55 mmol) in THF (30 mL) was added n-butyllithium (1.28
M, in cyclohexane, 0.43 mL) at -30 °C. After stirring for 4 h,
F igu r e 4. ORTEP diagram of [Cp′2HoOC(Bun)NPh]2 (7)
with the probability ellipsoids drawn at the 30% level.
normal range.22,23 The average Ho-O distance of 2.375-
(3) Å is longer than the values observed in [(MeOCH2-
CH2C5H4)2Ho(µ-OH)]2 [2.250(3) Å]24 and [(C5H5)Ho-
(PzMe2)(OSiMe2PzMe2)]2 [2.280(4) Å].23 The rather long
Ho-O distance in 7 may be attributed to the facts that
the oxygen atom is part of a delocalization chelating
ligand system and that the larger steric crowding
resulted from a higher coordination number. The O(1)-
Ho-O(1A) angle of 67.4(1)° is slightly less than typical
O-Ln-O angles in other dinuclear oxygen-bridge com-
plexes.13,23
Con clu sion s
The present results demonstrate that organolan-
thanide alkyl (aryl) complexes exhibit higher activity
to phenyl isocyanate than some transition metal
dialkyls.5b,16,21 Not only can the phenyl isocyanate be
inserted into each of the Ln-C σ-bonds of Cp′2LnR(THF)
(25) Zhou, X. G.; Huang, Z. E.; Cai, R. F.; Xie, M. H.; You, X. Z.; Xu,
Z. Chin. J . Inorg. Chem. 1998, 14, 68.
(26) Maginn, R. E.; Manastyrskj, S.; Dubeck, M. J . Am. Chem. Soc.
1963, 85, 672.
(24) Deng, D. L.; J iang, Y. Q.; Qian, C. T.; Wu, G.; Zheng, P. J . J .
Organomet. Chem. 1994, 470, 99.
(27) Qian, C. T.; Ye, C. Q.; Lu, H. Z.; Li, Y. Q.; Zhou, J . L.; Ge, Y.
W. J . Organomet. Chem. 1983, 247, 161.

Insertion Reaction of Phenyl Isocyanate
Organometallics, Vol. 20, No. 26, 2001 5705
to the mixture was added phenyl isocyanate (0.06 mL, 0.55
mmol) at -15 °C. The reaction mixture was subsequently
worked up by the method described above. Yellow crystals of
2 were obtained in 54% yield. Anal. Calcd for C46H56N2O2Dy2:
C, 55.58; H, 5.68; N, 2.82; Dy, 32.70. Found: C, 55.17; H, 5.64;
N, 2.86; Dy, 32.31. IR (KBr pellet, cm-1): 2729 m, 2671 m,
1670 w, 1600 w, 1571 m, 1554 w, 1462 s, 1377 s, 1304 m, 1155
w, 1074 m, 1028 w, 1009 w, 964 w, 821 w, 774 m, 754 m, 727
s, 694 m, 658 w, 590 m. MS: m/e [fragment, relative intensity
%] ) 917 [M - Cp′, 100], 838 [M - 2Cp′, 3], 498 [M/2, 15], 419
[M/2 - Cp′, 13], 340 [M/2 - 2Cp′, 8], 322 [Cp′2Dy, 15], 79 [Cp′,
23], 77 [Ph, 17].
[Cp ′2Er OC(Bu n )NP h ]2 (3). Following the procedure de-
scribed for 1, reaction of Cp′2ErCl (0.321 g, 0.89 mmol) with
n-butyllithium (1.15 M, 0.77 mL) and subsequently with
PhNCO (0.097 mL, 0.89 mmol) gave 3 as pink crystals. Yield:
0.277 g (62%). Anal. Calcd for C46H56N2O2Er2: C, 55.07; H,
5.62; N, 2.79; Er, 33.34. Found: C, 55.13; H, 5.66; N, 2.82; Er,
33.42. IR (KBr pellet, cm-1): 1604 m, 1571 m, 1463 s, 1377 s,
1341 m, 1240 w, 1071 w, 1031 w, 1012 m, 964 m, 827 m, 772
s, 754 s, 723 s, 702 m, 670 w, 619 w. MS: m/e [fragment,
relative intensity %] ) 921 [M - Cp′, 100], 842 [M - 2Cp′, 2],
500 [M/2, 17], 421 [M/2 - Cp′, 21], 342 [M/2 - 2Cp′, 3], 324
[Cp′2Er, 6], 245 [Cp′Er, 3], 79 [Cp′, 13].
The physical, analytical, and spectroscopic properties of the
compound were identical with that obtained above.
Ho[OC(Bu n
)NP h ]3 (6). To a solution of Cp′HoCl2(THF)3
(0.530 g, 1.00 mmol) in 45 mL of THF was added butyllithium
(1.15 M, 1.74 mL) at -30 °C. After stirring at this temperature
for 3 h, the solution was allowed to warm to 0 °C, where it
was stirred for 1.5 h. Then, the solution was cooled to -30 °C
and treated with 0.22 mL (2.0 mmol) of PhNCO. After stirring
for 3 h at -30 °C, the reaction mixture was slowly warmed to
ambient temperature and was stirred for 48 h. Removal of
solvent left yellow solids. The resulting solid was extracted
with cold toluene. The extract was evaporated to ca. 5 mL. A
yellow microcrystalline solid was slowly formed at 30 °C, which
disappeared at -15 °C. Yield: 0.22 g (63%). Anal. Calcd for
C
33H42O3N3Ho: C, 57.14; H, 6.10; N, 6.05; Ho, 23.78. Found:
C, 56.67; H, 6.05; N, 6.09; Ho, 23.85. IR (KBr pellet, cm-1):
1659 w, 1631 m, 1298 m, 774 w, 481 s.
[Cp ′2HoOC(Bu n )NP h ]2 (7). Further crystallization by dif-
fusion of hexane into the above mother liquor yielded yellow
crystals of 7, which were collected, washed with a minimal
amount of the mixture solution of THF and hexane, and dried
in a vacuum. Yield: 0.160 g (64%). Anal. Calcd for C46H56N2O2-
Ho2: C, 55.31; H, 5.65; N, 2.80; Ho, 33.03. Found: C, 55.43;
H, 5.66; N, 2.92; Ho, 33.42. MS: m/e [fragment, relative
intensity %] ) 919 [M - Cp′, 100], 863 [M - Cp′-BunH, 3],
840 [M - 2Cp′, 1], 822 [M - OC(Bun)NPh, 8], 742 [M - OC-
(Bun)NPh-Cp′H, 2], 680 [M - 4Cp′-2, 2], 499 [M/2, 12], 457
[M/2 - C3H6, 4], 420 [M/2 - Cp′, 12], 323 [Cp′2Ho, 4], 79 [Cp′,
2], 77 [Ph, 7], 57 [Bun, 1].
[Cp ′2DyOC(Np )NP h ]2 (4). To a stirred THF solution (10
mL) of n-butyllithium (1.68 mmol) at -15 °C was added
dropwise R-bromonaphthalene(NpBr) (0.23 mL, 1.68 mmol).
After stirring for 30 min, the reaction solution was allowed to
warm to room temperature and stirred for a further 30 min.
Then, the reaction solution was added to a solution of Cp′2-
DyCl (0.598 g, 1.68 mmol) in THF (25 mL) at -15 °C, and the
mixture was stirred at room temperature for 4 h. Phenyl
isocyanate (0.18 mL, 1.68 mmol) was added at -30 °C. The
reaction was stirred overnight. The solvent was removed in
vacuo. The residue solid was extracted with toluene. Recrys-
tallization by vapor diffusion of hexane into a toluene solution
afforded pale yellow crystals of 4‚THF. Yield: 0.50 g (52%).
Anal. Calcd for C62H60N2O3Dy2: C, 61.74; H, 5.01; N, 2.32; Dy,
26.95. Found: C, 61.24; H, 4.98; N, 2.32; Dy, 27.03. IR (KBr
pellet, cm-1): 3057 w, 1640 w, 1588 m, 1568 s, 1530 w, 1500
w, 1400 m, 1351 s, 1250 w, 1207 m, 1143 m, 1075 w, 1068 w,
1.035 m, 1013 m, 925 m, 870 w, 838 m, 776 s, 732 m, 702 s,
595 w, 558 m. MS: m/e [fragment, relative intensity %] ) 567
[M/2 - 1, 11], 553 [M/2 - CH3, 3], 488 [M/2 - Cp′H, 48], 410
[M/2 - 2Cp′, 1], 241 [Cp′Dy, 11], 127 [Np, 7], 91 [NPh, 100],
79 [Cp′, 9], 72 [THF, 1].
Str u ctu r e Deter m in a tion . Suitable single crystals of
complexes 1, 4‚THF, 5‚THF, and 7 were sealed in thin-walled
glass capillaries under argon for the X-ray diffraction study.
Crystal data and details of collection and refinement are
summarized in Table 5.
F or 1, diffraction experiments were performed on a Bruker
SMART 1000 CCD diffractometer (λ ) 0.71069 Å, ω-2θ scans).
Frames were integrated to a maximum 2θ angle of 52.76° with
the Siemens SAINT program to yield a total of 4875 reflections,
of which 4157 were independent (Rint ) 0.0188) and 3900 were
above 2σ(I). Laue symmetry revealed a triclinic crystal system,
and the final unit cell parameters were determined from the
least-squares refinement of three-dimensional centroids of
5102 reflections. Data were corrected for absorption with the
SADABS program.28 The structure was solved by direct
methods, expanded using Fourier technique, and refined on
F2 by full-matrix least-squares.29 All non-hydrogen atoms were
refined anisotropically, and all hydrogen atoms were included
in idealized positions with isotropic thermal parameters
related to those of the supporting carbon atoms, but were not
included in refinement. All calculations were performed by
using the SHELXS-97 crystallographic software package.30
F or 4‚THF, preliminary examination and intensity data
collection were carried out with an Enraf-Nonius CAD-
automatic diffractometer using graphite-monochromatized Mo
KR radiation. Accurate cell paramaters were obtained by the
least-squares refinement of the setting angles of 25 reflections
with 11.06° < θ < 12.62°. Intensity data were collected using
the ω-2θ scan mode and corrected for absorption and decay.
The structures were solved by direct methods and refined with
full-matrix least-squares on F2. The solvent molecule THF was
disordered, and no “model” could be proposed to “fit” THF to
the observed electron density maps, so bond distances were
constrained.
Gen er a l P r oced u r e for Ca ta lytic F or m a tion of [P h -
NCO]3 (5). Meth od A. A mixture of PhNCO (0.40 mmol),
[Cp′2DyOC(Bun)NPh]2 (0.20 mmol), and THF (15 mL) was
magnetically stirred at 0 °C for 8 h. The color of the solution
changed slowly from pale yellow to orange. After stirring for
a further 12 h at room temperature, the solvent was removed
by vacuum, and the resulting solid was extracted with toluene.
Crystallization from toluene/hexane afforded 5‚THF as pale
yellow crystals. Yield: 0.03 g (52%), mp 278 °C. Anal. Calcd
for C25H23N3O4: C, 69.91; H, 5.40; N, 9.78. Found: C, 69.72;
H, 5.28; N, 9.91. IR (KBr pellet, cm-1): 3065 w, 1706 s, 1590
m, 1488 s, 1455 s, 1414 s, 1290 m, 1219 m, 1157 w, 1074 s,
1028 m, 918 m, 814 m, 752 s, 690 s, 590 s. MS: m/e [fragment,
relative intensity %] ) 357 [M, 100], 238 [M - PhNCO, 6],
119 [PhNCO, 94], 77 [Ph, 8]. 5 was also obtained (55% yield)
from the higher molar ratio of PhNCO to 2 (10:1).
F or 5‚THF, the X-ray intensity data were collected as for 1
above. Frames were integrated to a maximum 2θ angle of
Meth od B. To 20 mL THF solution of Cp′2DyBun (0.525
mmol) at -20 °C was added an excess of phenyl isocyanate
(1.82 mmol), and the solution was stirred overnight. After
warming to room temperature and stirring for 3 h the reaction
was quenched with water and extracted with toluene. The
organic portions were combined and washed with water. The
solvent was removed in vacuo. Yellow crystals were obtained
by recrystallization in toluene/hexane. Yield: 0.132 g (61%).
(28) Sheldrick, G. M. SADABS, A Program for Empirical Absorption
Correction; Go¨ttingen, Germany, 1998.
(29) SHLXTL PLUS, Siemens Analytical X-ray Institute Inc., XS:
Program for Crystal Structure Solution, XL: Program for Crystal
Structure Determination, XP: Interactive Molecular Graphics, 1990.
(30) Sheldrick, G. M. SHELXL-97, Program for the refinement of
the crystal structure; University of Go¨ttingen: Germany, 1997.

5706 Organometallics, Vol. 20, No. 26, 2001
Ta ble 5. Cr ysta l a n d Da ta Collection P a r a m eter s of Com p lexes 1, 4‚THF , 5‚THF , a n d 7
Zhou et al.
1
4‚THF
5‚THF
7
formula
Sm2C46H56N2O2
969.62
yellow
Dy2C62H60O3N2
1206.12
yellow
0.68 × 0.20 × 0.20
orthorhombic
Fdd2
C25H23N3O4
429.46
pale yellow
0.35 × 0.25 × 0.20
triclinic
Ho2C46H56O2N2
998.79
yellow
0.80 × 0.50 × 0.30
monoclinic
P21/n
molecular weight
cryst color, shape
cryst dimens (mm)
cryst syst
space group
lattice params
a (Å)
0.50 × 0.40 × 0.30
triclinic
P1h
P1h
9.2183(7)
11.1378(9)
11.4694(9)
111.920(1)
103.173(1)
97.794(1)
1031.5(1)
1
15.815(3)
23.014(5)
28.168(6)
90.00
90.00
90.00
10252(4)
8
1.563
11.2424(8)
11.3102(9)
11.4925(9)
91.145(2)
115.072(1)
115.093(1)
1108.5(2)
2
13.494(3)
8.8476(18)
17.708(4)
90.00
98.40(3)
90.00
2091.4(7)
2
1.586
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
Dc (g cm-3
F(000)
)
1.535
470
1.287
452
4816
992
radiation (λ ) 0.71069 Å) Mo KR
Mo KR
293(2)
ω-2θ
Mo KR
Mo KR
293(2)
ω-2θ
temp (K)
scan type
298(2)
ω-2θ
2.856
298(2)
ω-2θ
0.089
µ (mm-1
)
2.941
3.793
hkl range
-11-11, -13-11, -14-14 -19-16, -16-28, -34-0 -7-13, -13-13, -13-13 0-16, 0-10, -21-21
2.01-26.38
4875
4157 (Rint ) 0.0188)
3900[I > 2σ(I)]
θ range (deg)
no. of reflns measd
no. of unique reflns
no. of reflns obsd
refinement method
no. of variables
w
1.72-26.00
5174
2566 (Rint ) 0.1543)
1653[I > 2σ(I)]
2.04-25.02
4653
1.78-26.02
3993
3831 (Rint ) 0.0353)
3499[I > 2σ(I)]
3900 (Rint ) 0.0162)
3250
full-matrix least-squares on F2
238
144
370
235
1/[σ2(Fo2) + (0.064P)2 +
0.9171P] with P )
1/[σ2(Fo2) + (0.0884P)2 + 1/[σ2(Fo2) + (0.0808P)2 +
1/[σ2(Fo2) + (0.0557P)2 +
0.3917P] with P )
0.0000P] with P )
0.1972P] with P )
2
2
2
2
(Fo + 2Fc2)/3
(Fo + 2Fc2)/3
(Fo + 2Fc2)/3
(Fo + 2Fc2)/3
goodness of fit on F2
1.057
0.967
1.021
1.158
final R indices [I > 2σ(I)] R1 ) 0.0324
R1 ) 0.0692
wR2 ) 0.1643
R1 ) 0.1148
wR2 ) 0.1875
1.400, -2.138
R1 ) 0.0443
wR2 ) 0.1271
R1 ) 0.0521
wR2 ) 0.1370
0.260, -0.153
R1 ) 0.0258
wR2 ) 0.0833
R1 ) 0.0300
wR2 ) 0.0845
0.784, -0.824
wR2 ) 0.0866
R indices (all data)
R1 ) 0.0345
wR2 ) 0.0891
1.223, -1.191
largest diff peak and
hole (e Å-3
)
52.78° with the Siemens SAINT program to yield a total of
3883 reflections, of which 3274 were independent (Rint
and for Lorentz and polarization factors. The structure was
solved by direct methods with the program SHELXTL.31 In
the final cycles, all non-hydrogen atoms were refined aniso-
tropically and all hydrogen atoms were fixed at idealized
positions.
)
0.0181) and 3105 were above 2σ(I). Laue symmetry revealed
a triclinic crystal system, and the final unit cell parameters
were determined from the least-squares refinement of three-
dimensional centroids of 3665 reflections. A total of 3274
independent reflections were collected in the range 2.84° <
θ < 25.02° by using the ω-2θ scan mode at 298(2) K; 3105
observable reflections with I > 2σ(I) were used in the succeed-
ing refinements. The intensities were corrected for Lorentz-
polarization effects and empirical absorption with the SADABS
program. The structure was solved by direct methods using
the SHELXL-97 program. Refinement on F2 was performed
by full-matrix least-squares with anisotropic thermal param-
eters for all non-hydrogen atoms. There is one tetrahydrofuran
molecule present per formula unit. All calculations were
performed using the Bruker Smart program.
Ack n ow led gm en t. We thank the National Natural
Science Foundation of China and the Research Fund
for the Doctoral Program of Higher Education of China
and the Shuguang Foundation of Shangai Education
Committee of China for financial support.
Su p p or tin g In for m a tion Ava ila ble: Tables of atomic
coordinates and thermal parameters, all bond distances and
angles, and experimental data for all structurally character-
ized complexes. This material is available free of charge via
the Internet at http://pubs.acs.org.
F or 7, the X-ray intensity data were collected on a Rigaku
AFC5R diffractometer. Final cell parameters were based on a
least-squares analysis of 20 reflections in well-separated
regions of reciprocal space, all having 7.61° < θ < 9.87°. All
3831 unique data were corrected for the effects of absorption
OM010346Y
(31) Sheldrick, G. M. SHELXTL, Structure Analysis Program;
Siemens Industrial Automation Inc.: Madison, WI, 1994.