Reactivity of [(2-phosphino)ethenyl]zirconocene chloride toward CpM(CO)3Cl (M = Mo, W): Formation of [(3-phosphino)propenoyl] dicarbonyl(cyclopentadienyl)metal, {CpM(CO)2[(CO)CR=CRPPh 2]}

Article abstract of DOI:10.1021/om900595w

Reaction of [(2-phosphino)ethenyl]zirconocene chloride (1) with CpM(CO)₃Cl (M=Mo, W) in THF yielded the[(3-phosphino)propenoyl] dicarbonyl(cyclopentadienyl)metals {CpM(CO)₂[(CO)CR=CRPPh ₂]} (2). When the reaction between [

Full text of DOI:10.1021/om900595w

Organometallics 2009, 28, 6827–6830 6827
DOI: 10.1021/om900595w
Reactivity of [(2-Phosphino)ethenyl]zirconocene Chloride toward
CpM(CO)3Cl (M=Mo, W): Formation of
[(3-Phosphino)propenoyl]dicarbonyl(cyclopentadienyl)metal,
{CpM(CO)2[(CO)CRdCRPPh2]}
Xiaoyu Yan,† Bingran Yu,§ Lan Wang,† Ning Tang,§ and Chanjuan Xi*,‡,†
†Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology (Ministry of Education),
Department of Chemistry, Tsinghua University, Beijing 100084, People’s Republic of China, ‡State Key
Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China,
and §State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000,
People’s Republic of China
Received July 9, 2009
Summary: Reaction of [(2-phosphino)ethenyl]zirconocene
chloride (1) with CpM(CO)3Cl (M=Mo, W) in THF yielded
the [(3-phosphino)propenoyl]dicarbonyl(cyclopentadienyl)metals
{CpM(CO)2[(CO)CRdCRPPh2]} (2). When the reaction be-
tween [(2-phosphino)ethenyl]zirconocene chloride (1) and
CpMo(CO)3Cl was carried out in the presence of a catalytic
amount of Pd(CH3CN)2Cl2, [(3-phosphino)propenoyl]dicarb-
Results and Discussion
The initial experiment showed that reaction of (Z)-[(2-
diphenylphosphino)(1,2-diphenyl)ethenyl]zirconocene chlo-
ride (1a) with CpMo(CO)3Cl at 50 °C for 1 day led to the
formation of complex 2a in 25% (NMR) yield. Most of
starting material 1a was unreacted. When the reaction time
was extended to 10 days, complex 2a was obtained in 75%
(NMR) yield with some amount of uncharacterised bypro-
duct. The starting material 1a was completely consumed.
Speculating that transmetalation of Zr-C to Cu-C6 or
Pd-C2,7 might accelerate the reaction to form complex 2a,
we conducted the reaction in the presence of a catalytic
amount of CuCl. Under these conditions, complex 2a
[45% (NMR) yield] and some uncharacterized byproduct
were formed within 3 days. When the reaction was carried
out in the presence of a catalytic amount of Pd(CH3CN)2Cl2,
within 4 days, complex 2a was observed as sole product in
95% (NMR) yield. Removal of the solvent and further
purification by column chromatography on silica gel
(petroleum ether/EtOAc=3:1) afforded 2a as an air-stable
red solid in 76% isolated yield. Compound 2a was charac-
terized as (Z)-[(3-diphenylphosphino)(2,3-diphenylpropen-
oyl)]dicarbonyl(cyclopentadienyl)molybdenum, {CpMo(CO)2-
[(CO)CPhdCPhPPh2]}, by its 1H, 13C, and 31P NMR spectra.
The 1H NMR spectrum of 2a showed a single peak at 4.94 ppm
assigned to Cp protons. In its 13C NMR spectrum, Cp carbons
appeared at 94.5 ppm and an alkenyl unit appeared at 156.3
and 137.5 ppm. Two terminal carbonyl resonances were also
observed at 235.5 ppm. The acyl CO was observed at 169.1 ppm.
The 31P NMR spectrum of 2a showed a single peak at 99.4 ppm,
onyl(cyclopentadienyl)molybdenum,
{CpMo(CO)2[(CO)-
CRdCRPPh2]}, was exclusively observed. When [(2-phosphi-
no)ethenyl]zirconocene chloride (1) and MeCpW(CO)3Cl
were reacted in the presence of a catalytic amount of CuCl,
[(3-phosphino)propenoyl]dicarbonyl(methylcyclopentadienyl)-
tungsten, {MeCpW(CO)2[(CO)CRdCRPPh2]}, was formed.
Their structures are determined by X-ray diffraction analysis.
Introduction
We previously reported that zirconophosphination of alkynes
gave [(2-phosphino)ethenyl]zirconocene chlorides, which could
be transformed into β-functionalized alkenylphosphines by
coupling reactions with various electrophiles in the presence of
CuCl. In these reactions, transmetalation of Zr-CtoCu-Cwas
necessary.1 Recently, we reported reaction of [(2-phosphino)-
ethenyl]zirconocene chlorides with Pd(CH3CN)2Cl2 to give
dimeric [(2-phosphino)ethenyl]palladium chlorides,2 which are
useful catalysts in coupling reactions.3 Moreover, the [(2-phos-
phino)ethenyl]zirconocene chlorides showed high activities for
ethylene polymerization as well as copolymerization of ethylene
with R-olefin or norbornene in the presence of methylaluminox-
ane (MAO) as cocatalyst.4 Having an interest in the develop-
ment of this program, we now report on the reactivity of [(2-
phosphino)ethenyl]zirconocene chlorides toward CpM(CO)3
Cl (M=Mo, W)5 to afford [(3-phosphino)propenoyl]dicarbo-
nyl(cyclopentadienyl)metal {CpM(CO)2[(CO)CRdCRPPh2]}.
This reaction involves a transmetalation-CO insertion sequence.
(6) Leading references: (a) Takahashi, T.; Kotora, M.; Kasai, K.;
Suzuki, N.; Nakajima, K. Organometallics 1994, 13, 4184. (b) Takahashi,
T.; Hara, R.; Nishihara, Y.; Kotora, M. J. Am. Chem. Soc. 1996, 118, 5154.
(c) Takahashi, T.; Xi, Z.; Yamazaki, A.; Liu, Y.; Nakajima, K.; Kotora, M.
J. Am. Chem. Soc. 1998, 120, 1672. (d) Takahashi, T.; Sun, W.-H.; Liu, Y.;
Nakajima, K.; Kotora, M. Organometallics 1998, 17, 3841. (e) Kotora, M.;
Xi, C.; Takahashi, T. Tetrahedron Lett. 1998, 39, 4321. (f) Xi, C.; Kotora,
M.; Nakajima, K.; Takahashi, T. J. Org. Chem. 2000, 65, 945. (g) Takahashi,
T.; Li, Y.; Ito, T.; Xu, F.; Nakajima, K.; Liu, Y. J. Am. Chem. Soc. 2002, 124,
1144. (h) Chen, C.; Xi, C.; Jiang, Y.; Hong, X. J. Am. Chem. Soc. 2005, 127,
*Corresponding author. E-mail: cjxi@tsinghua.edu.cn.
(1) Xi, C.; Yan, X.; Lai, C. Organometallics 2007, 26, 1084.
(2) Yan, X.; Xi, C. Organometallics 2008, 27, 152.
(3) Yan, X.; Liu, Y.; Xi, C. Appl. Organomet. Chem. 2008, 22, 341.
(4) Hao, P.; Zhang, S.; Yi, J.; Sun, W.-H. J. Mol. Catal. A: Chem.
2009, 302, 1.
(5) (a) Sun, W.-H.; Wang, H.-Q.; Yang, S.-Y.; Zhou, Q. F.; Yu, K.-B.
Polyhedron 1994, 13, 389. (b) Sun, W.-H.; Yang, S.-Y.; Wang, H.-Q.; Zhou,
Q. F.; Yu, K.-B. J. Organomet. Chem. 1994, 465, 263.
ꢀ
ꢀ ꢀ
8024. (i) Dufkova, L.; Kotora, M.; Císarova, I. Eur. J. Org. Chem. 2005,
2491.
(7) Negishi, E.; Takahashi, T.; Baba, S.; Van Horn, D. E.; Okukado,
N. J. Am. Chem. Soc. 1987, 109, 2393.
(8) Garrw, P. E. Chem. Rev. 1981, 81, 229.
r
2009 American Chemical Society
Published on Web 11/04/2009
pubs.acs.org/Organometallics

6828 Organometallics, Vol. 28, No. 23, 2009
Yan et al.
Figure 1. Molecular structure of 2a. Thermal ellipsoids are
shown at 30% probability; hydrogen atoms have been omitted
˚
for clarity. Selected bond lengths (A) and angles (deg): Mo-
(1)-C(30), 1.958(4); Mo(1)-C(16),1.970(3); Mo(1)-C(20),
2.237(3); Mo(1)-P(2), 2.4091(8); P(2)-C(2), 1.838(3); C(2)-C-
(5), 1.342(4); C(5)-C(20), 1.530(4); C(30)-Mo(1)-C(16),
77.39(16); C(30)-Mo(1)-C(20), 73.95(15); C(16)-Mo(1)-C-
(20), 131.71(15); C(30)-Mo(1)-P(2), 109.11(13); C(16)-Mo-
Figure 2. Molecular structure of 2c. Thermal ellipsoids are
shown at 30% probability; hydrogen atoms have been omitted
for clarity. Selected bond lengths (A) and angles (deg): W(1)-C-
˚
(16), 1.969(6); W(1)-C(30), 1.973(8); W(1)-C(20), 2.239(6);
W(1)-P(2), 2.4189(15); P(2)-C(2), 1.836(6); C(20)-C(5),
1.535(8); C(2)-C(5), 1.342(8); C(16)-W(1)-C(30), 76.3(3); C-
(16)-W(1)-C(20), 131.0(2); C(30)-W(1)-C(20), 75.4(2); C-
(16)-W(1)-P(2), 77.20(18); C(30)-W(1)-P(2), 107.5(2);
C(20)-W(1)-P(2), 74.34(16); C(2)-P(2)-W(1), 109.56(19); C-
(5)-C(20)-W(1), 123.4(4); C(5)-C(2)-P(2), 112.7(4); C-
(2)-C(5)-C(20), 119.0(5).
(1)-P(2),
79.43(11);
C(20)-Mo(1)-P(2),
74.45(8);
C(2)-P(2)-Mo(1), 109.45(9); C(5)-C(2)-P(2), 112.6(2); C-
(2)-C(5)-C(20), 119.0(2).
which showed that the phosphorus was coordinated to molyb-
denum.8 Using tolyl groups instead of phenyl groups on the
alkene, (Z)-[(3-diphenylphosphino)(2,3-ditolylpropenoyl)]dic-
arbonyl(cyclopentadienyl)molybdenum, 2b, was obtained in
53% isolated yield (eq 1).
˚
1.838(3) A, respectively, which are comparable to the corre-
sponding values found in other molybdenum complexes.9a
Reaction of the analogous tungsten complex (η5-
C5H4CH3)W(CO)3Cl with (Z)-[(2-diphenylphosphino)(1,2-
diphenyl)ethenyl]zirconocene chloride (1a) in the presence of
a catalytic amount of Pd(CH3CN)2Cl2 gave complex 2c after
14 days in very low yield. When the reaction was carried out in
the presence of a catalytic amount of CuCl during 14 days, 1a
was completely consumed and complex 2c was the sole
product (eq 2). Removal of solvent and further purification
by column chromatography on silica gel (hexane/EtOAc=5:1)
gave2c as an orange solid in 73% isolated yield. Red crystals of
2c suitable for X-ray analysis were obtained by diffusing
hexane into its CH2Cl2 solution at room temperature. The
structure of 2c is identical to that of 2a except for the different
metal atom. An ORTEP plot of 2c appears in Figure 2.
To further confirm the structure of the product, red
crystals of 2a suitable for X-ray analysis were obtained by
diffusing hexane into an ethyl acetate solution of 2a at room
temperature. The structure of 2a in Figure 1 clearly shows the
formation of the (Z)-[(3-diphenylphosphino)(2,3-diphenyl-
propenoyl)]dicarbonyl(cyclopentadienyl)molybdenum com-
plex. The molybdenum atom is in a squarepyramidal envir-
onment with the four basal positions being occupied by two
carbonyl ligands, the diphenylphosphido group, and an acyl-
like carbonyl group. The set of Mo(1), P(2), C(2), C(5), and
C(20) is slightly puckered. The length of the C(2)-C(5) bond
˚
of the alkene unit is normal at 1.342(4) A. The Mo(1)-P(2)
˚
bond is 2.4091(8) A, slightly shorter than that reported in
other Mo complexes with phosphorus ligands (such as
2.433(2) A in {CpMo(CO)2[Ph2PCHdC(Ph)CO]},9a 2.467(2)
Transmetalations of the C-Zr bond to C-Cu,6 C-Ni,10
C-Al,11 and C-Pd2,7 bonds have been extensively observed.
˚
A in Mo2(μ-Cl){[(μ-Ph2PC(H)C(H)](CO)2Cp2}.9b The lengths
˚
of the Mo(1)-C(20) and P(2)-C(2) bonds are 2.237(3) and
(10) (a) Takahashi, T.; Tsai, F.-Y.; Li, Y.; Nakajima, K.; Kotora, M.
J. Am. Chem. Soc. 1999, 121, 11093. (b) Takahashi, T.; Tsai, F.-Y.; Li, Y.;
Wang, H.; Kondo, Y.; Yamanaka, M.; Nakajima, K.; Kotora, M. J. Am.
Chem. Soc. 2002, 124, 5059. (c) Takahashi, T.; Li, Y.; Stepnicka, P.;
Kitamura, M.; Liu, Y.; Nakajima, K.; Kotora, M. J. Am. Chem. Soc. 2002,
124, 576.
(9) (a) Adams, H.; Bailey, N. A.; Day, A. N.; Morris, M. J.; Harrison,
M. M. J. Organomet. Chem. 1991, 407, 247. (b) Conole, G.; Hill, K. A.;
McPartlin, M.; Mays, M. J.; Morris, M. J. J. Chem. Soc., Chem. Commun.
1989, 688.

Note
Organometallics, Vol. 28, No. 23, 2009 6829
Scheme 1
CDCl3, Me4Si): δ 94.5 (Cp), 127.3 (aromatic C), 127.6 (aromatic
C), 128.3 (d, JPC=10.8 Hz, aromatic C), 128.9 (d, JPC=9.3 Hz,
aromatic C), 129.1 (aromatic C), 129.9 (aromatic C), 130.4
(aromatic C), 131.3 (d, JPC =10.0 Hz, aromatic C), 131.5 (d,
J
PC=46.6 Hz, aromatic C), 133.2 (d, JPC=11.5 Hz, aromatic C),
135.5 (d, JPC=20.8 Hz, aromatic C), 136.4 (aromatic C), 137.5
(d, JPC=38.7 Hz, alkenyl C), 156.3 (d, JPC=29.4 Hz, alkenyl C),
169.1 (d, JPC=44.5 Hz, CdO), 235.5 (CO). 31P NMR (81 MHz,
CDCl3, 85% H3PO4): δ 99.4. Positive ion ESI-MS: 582.6 (M -
CO þ Hþ). Anal. Calcd for C34H25PO3Mo: C, 67.11; H, 4.14.
Found: C, 67.07; H, 4.28.
(Z)-[(3-Diphenylphosphino)(2,3-ditolylpropenoyl)]dicarbonyl-
(cyclopentadienyl)molybdenum, Complex 2b. (Z)-[(2-dipheny-
lphosphino)(1,2-ditolyl)ethenyl]zirconocene chloride (1b) (259
mg, 0.4 mmol), CpMo(CO)3Cl (134 mg, 0.5 mmol), PdCl2-
(CH3CN)2 (5.2 mg, 0.02 mmol), and THF (5 mL) were added
to the Schlenk tube, and the mixture was stirred for 4 days at 50 °C.
Removal of the solvent and further purification by column
chromatography on silica gel (hexane/EtOAc = 3:1) afforded
the title compound as a yellow solid (134 mg, 0.21 mmol,
isolated yield 53%). Mp: 162-164 °C (dec). IR (KBr, cm-1):
In combination with these known facts, a plausible mechan-
ism is shown in Scheme 1. In the first step, (Z)-[(2-phosphi-
no)ethenyl]zirconocene chloride (1) is transmetalated with
CuCl or PdCl2 to give (Z)-[(2-phosphino)ethenyl]copper
or Z-[(2-phosphino)ethenyl]palladium chloride (3), respec-
tively, which transmetalate again with CpM(CO)3Cl, form-
ing intermediate 4. Subsequently, CO insertion forms
(Z)-[(3-phosphino)propenoyl]dicarbonyl(cyclopentadienyl)-
molybdenum or (Z)-[(3-phosphino)propenoyl]dicarbonyl-
(cyclopentadienyl)tungsten, {CpM(CO)2[(CO)CRdCRPPh2]} (2).
Further investigations of the reactivity of (Z)-[(3-
phosphino)propenoyl]dicarbonyl(cyclopentadienyl)metal comp-
lexes are currently under way in our laboratory.
1
1960 1937 1581. H NMR (300 MHz, CDCl3, Me4Si): δ 2.08
(s, CH3, 3H), 2.23 (s, CH3, 3H), 4.90 (s, Cp, 5H), 6.41 (d, JHH
=
8.2 Hz, aromatic, 2H), 6.64 (d, JHH =8.2 Hz, aromatic, 2H),
6.80-7.67 (m, aromatic, 14H). 13C NMR (75 MHz, CDCl3,
Me4Si): δ 21.2 (CH3), 21.4 (CH3), 94.7 (Cp), 128.0 (aromatic C),
127.6 (aromatic C), 128.4 (aromatic C), 128.9 (d, aromatic C,
JPC =9.3 Hz), 129.1 (aromatic C), 129.9 (aromatic C), 130.2
(aromatic C), 130.4 (aromatic C), 132.4 (d, aromatic C, JPC
=
14.3 Hz,), 132.8 (d, aromatic C, JPC = 10.8 Hz), 133.1 d,
(aromatic C, JPC = 11.4 Hz), 133.4 (aromatic C), 136.7 (d,
alkenyl C, JPC=27.2 Hz), 155.7 (d, alkenyl C, JPC=29.4 Hz),
168.8 (d, CdO, JPC=46.7 Hz), 235.9 (CO). 31P NMR (81 MHz,
CDCl3, 85% H3PO4): δ 96.9. Anal. Calcd for C36H29MoO3P: C,
67.93; H, 4.59. Found: C, 67.84; H, 4.55.
Experimental Section
1. General Procedures. All manipulations were conducted in
Schlenk tubes under nitrogen with a slightly positive pressure.
The reaction progress was monitored by 31P NMR spectrosco-
py. The 31P NMR-based yields were obtained in proportion to
the integral area of all the 31P NMR signals determined by
integration. Tetrahydrofuran (THF) was refluxed and freshly
distilled from dark purple solutions of sodium and benzophe-
Representative Procedure for the Preparation of (Z)-[(3-
diphenylphosphino)(2,3-diphenylpropenoyl)]dicarbonyl(methylc-
yclopentadienyl)tungsten, 2c. (Z)-[(2-diphenylphosphino)(1,2-
diphenyl)ethenyl]zirconocene chloride (1a) (248 mg, 0.4 mmol),
MeC5H4W(CO)3Cl (191 mg, 0.5 mmol), CuCl (2.2 mg, 0.02 mmol),
and THF (5 mL) were added to the Schlenk tube, and the
mixture was stirred for 14 days at 50 °C. Removal of the solvent
and further purification by column chromatography on silica
gel (hexane/EtOAc = 5:1) afforded the title compound as an
orange solid (210 mg, 0.29 mmol, isolated yield 73%). Single
crystals were obtained by diffusing hexane into a CH2Cl2
solution at room temperature. Mp: 102-104 °C (dec). IR
1
none under a nitrogen atmosphere. H NMR and 13C NMR
spectra were recorded on a JEOL 300 NMR spectrometer with
tetramethylsilane (TMS) as an internal standard. 31P NMR
spectra were recorded on a Bruker AC 200 NMR spectrometer
at 81 MHz under 1H decoupled conditions using 85% H3PO4 (δP=
0 ppm) as an external standard. Mass spectra were obtained using a
Bruker Esquire ion trap mass spectrometer in positive ion mode.
Elemental analyses were performed on a Flash EA 1112 instrument.
Melting points were determined with a digital electrothermal
apparatus without calibration.
1
(KBr, cm-1): 1960, 1930, 1571. H NMR (300 MHz, CDCl3,
Me4Si): δ 2.05 (s, CH3, 3H), δ 4.70 (s, Cp, 2H), δ 4.80 (s, Cp, 1H),
5.07(s, Cp, 1H), 5.27 (s, CH2Cl2, 2H), 6.48-7.71 (m, aromatic,
20H). 13C NMR (75 MHz, CDCl3, Me4Si): δ 14.1 (CH3), 53.6
(CH2Cl2), 91.5 (Cp), 92.5 (Cp), 93.1 (Cp), 108.6 (Cp), 127.2
2. Representative Procedure for the Preparation of (Z)-[(3-
Diphenylphosphino)(2,3-diphenylpropenoyl)]dicarbonyl(cyclope-
ntadienyl)molybdenum, Complex 2a. (Z)-[(2-diphenylphosph-
ino)(1,2-diphenyl)ethenyl]zirconocene chloride (1a) (248 mg,
0.4 mmol), CpMo(CO)3Cl (134 mg, 0.5 mmol), PdCl2(CH3CN)2
(5.2 mg, 0.02 mmol), and THF (5 mL) were added to the Schlenk
tube, and the mixture was stirred for 4 days at 50 °C. 2a was
formed exclusively. 31P NMR (81 MHz, THF, 85% H3PO4): δ
99.8. Removal of the solvent and further purification by column
chromatography on silica gel (petroleum ether/EtOAc = 3:1)
afforded the title compound as a red solid (185 mg, 0.30 mmol,
isolated yield 76%). Mp: 209-211 °C (dec). IR (KBr: cm-1):
1960, 1884, 1670. 1H NMR (300 MHz, CDCl3, Me4Si): δ 4.94 (s,
Cp, 5H), 6.52-7.74 (m, aromatic, 20H). 13C NMR (75 MHz,
(aromatic C), 127.6 (aromatic C), 128.3 (d, aromatic C, JPC
=
10.0 Hz), 128.9 (d, aromatic C, JPC=9.3 Hz), 129.2 (aromatic
C), 130.4 (aromatic C), 130.7 (aromatic C), 131.3 (d, aromatic
C, JPC=9.3 Hz,), 133.5 (d, aromatic C, JPC=10.8 Hz), 134.4
(aromatic C), 135.5 (d, aromatic C, JPC = 20.1 Hz), 136.0
(aromatic C), 137.5 (d, alkenyl C, JPC = 43.7 Hz), 154.8 (d,
alkenyl C, JPC=33.0 Hz), 172.2 (d, CdO, JPC=38.7 Hz), 227.6
(CO), 237.5 (J=19.3 Hz, CO). 31P NMR (243 MHz, CDCl3,
85% H3PO4): δ 73.6 (s and d, 1JWP=164.5 Hz). Anal. Calcd for
C35H27PO3W CH2Cl2: C, 54.37; H, 3.68. Found: C, 54.66;
H, 3.78.
3
3. X-ray Crystallographic Studies. Single-crystal X-ray dif-
fraction studies for 2a and 2c were carried out on a Bruker
SMART 1000 CCD diffractometer with graphite-mono-
˚
chromated Mo KR radiation (λ, 0.71073 A). Cell parameters
were obtained by global refinement of the positions of all
collected reflections. Intensities were corrected for Lorentz
and polarization effects and empirical absorption. The
(11) (a) Negishi, E.; Yoshida, T. Tetrahedron Lett. 1980, 21, 150.
(b) Boardman, L. D.; Negishi, E. Tetrahedron Lett. 1982, 23, 3327. (c) Xi,
Z.; Li, P. Angew. Chem., Int. Ed. 2000, 39, 2950.

6830 Organometallics, Vol. 28, No. 23, 2009
Yan et al.
Table 1. Crystal Data and Refinement Data for 2a and 2c
2a
2c
empirical formula
fw
cryst color
temperature (K)
cryst syst
C
608.45
red
293(2)
orthorhombic
Pbca
12.718(3)
13.779(3)
31.857(6)
5582.6(19)
8
34H25MoO3P
C35H27Cl0O3PW
710.39
red
293(2)
orthorhombic
Pbca
12.653(3)
13.805(3)
31.852(6)
5563.7(19)
8
space group
˚
a (A)
˚
b (A)
˚
c (A)
3
volume (A )
˚
Z
Dcalc (g cm-3
)
1.448
0.561
1.696
4.246
M (mm-1
F(000)
cryst size (mm)
)
2480
0.50 ꢀ 0.40 ꢀ 0.30
2800
0.32 ꢀ 0.30 ꢀ 0.28
θ range (deg)
limiting indices
reflns collected
unique reflns
1.28-27.40
1.28-27.42
-16 e h e 16, -17 e k e 17, -41 e l e 41
11 637
6273
-16 e h e 16, -17 e k e 17, -41 e l e 41
10 972
6246
completeness to θ (%)
absorp correction
no. of params
98.8 (θ = 27.40°)
empirical
352
98.4 (θ = 27.42°)
empirical
361
goodness-of-fit on F2
final R indices [I > 2σ(I)]
R indices (all data)
1.148
1.348
R1 = 0.0386, wR2 = 0.1094
R1 = 0.0550, wR2 = 0.1143
0.353 and -0.640
R1 = 0.0549, wR2 = 0.1053
R1 = 0.0721, wR2 = 0.1106
1.407 and -2.014
-3
˚
largest diff peak and hole (e A
)
structures were solved by direct methods and refined by full-
matrix least-squares on F2. All non-hydrogen atoms were
refined anisotropically. All hydrogen atoms were placed in
calculated positions. Structure solution and refinement were
performed by using the SHELXL-97 package.12 Crystal data
and processing parameters for 2a and 2c are summarized in
Table 1.
Acknowledgment. This work has been supported by the
National Natural Science Foundation of China (20372041,
20872076). We thank Dr. Peng Hao for the single-crystal
X-ray analysis. Prof. Dietmar Seyferth is gratefully ac-
knowledged for his kind editorial and English corrections.
Supporting Information Available: X-ray crystallography data
in CIF format for complexes 2a and 2c. These materials are
available free of charge via the Internet at http://pubs.acs.org.
(12) Sheldrick, G. M. SHELXTL-97, Program for the Refinement of
Crystal Structures; University of Gottingen: Germany, 1997.