N. Kongprakaiwoot et al. / Journal of Organometallic Chemistry 689 (2004) 3350–3356
3355
3,6-difluoro-2,5-bis(diphenylphosphino)benzene (1.00 g,
1.56 mmol ) in 120 ml THF at ꢀ80 °C was added n-BuLi
(2.1 equivalent) as a 1.6 M solution in hexanes. The mix-
ture was stirred for 1 h at ꢀ80 °C, and then was treated
with a solution of 2.3 equivalents of the corresponding
ClPR2 in 10 ml of THF. After stirring for another hour
at ꢀ80 °C the mixture was allowed to warm up to room
temperature overnight.
diffractometer (Enraf-Nonius CAD4) and centered in
the beam path. Standard CAD4 centering, indexing,
and data collection programs were utilized [30]. Twenty-
five reflections between 10° and 15° in h were located by
a random search pattern, centered and used in indexing.
Final cell constants and orientation matrix were ob-
tained by collecting appropriate preliminary data and
refined by a least squares fit. During data collection,
three intensity standards and three orientation stand-
ards were measured at regular intervals to measure the
rate of decay of the crystal and to accommodate for
crystal movement.
3.2.3. 1,2,4,5-(PPh2)4-C6F2 (2a)
The reaction mixture contained pale yellow precipi-
tate, which was filtered off and extracted with toluene
(70 ml).
Data were first reduced and corrected for absorption
using psi-scans [31] and then solved using the program
SIR-02 [32], which afforded nearly complete solutions
for the non-H atoms in all cases. These programs were
utilized using the WinGX interface [33]. The models
were then refined using SHELXL-97 [34] first with iso-
tropic and then anisotropic thermal parameters to con-
vergence. The positions and isotropic thermal
parameters of the different H-atoms were constrained
according to the specifics arranged in the SHELXL-97
program. This constituted the final model for 2a and
2c but it was apparent that two of the C atoms in one
of the isopropyl groups in 2b were disordered. This
was accounted for by including atoms at the various
sites and refining the occupancies constrained to unity.
This resulted in a 81(2)% to 19(2)% disorder in two of
the carbon atoms in this isopropyl group.
The extract was filtered, the filtrate was placed at ꢀ28
°C, yielding pale yellow crystals after one week (isolated
by filtration). Yield: 1.07 g (40%). Melting point: 274–
276 °C. 1H NMR (CDCl3): d 7.19 (m). 31P NMR
(CDCl3): d ꢀ11.31 (s); 19F NMR (C6D6): d ꢀ78.53 (s).
MS (EI): m/z = 850 (M+). Anal. Calc. for C54H40F2P4:
C, 76.23; H, 4.74. Found: C, 74.92; H, 4.72%. (Results
consistently low on carbon were obtained on repeated
runs on two different batches of the material. Multinu-
clear NMR and GC/MS spectroscopic characterizations
revealed no impurities.)
3.2.4. 1,4-(PPh2)2-2,5-(PiPr2)2-C6F2 (2b)
The reaction mixture was filtered, volatiles removed
under vacuo to yield an oily yellow solid, which was ex-
tracted with a 1:1 mixture of hexanes and toluene (100
ml). Yellow crystals of 2b precipitated on standing at
ꢀ28 °C for one day, and were isolated by filtration.
Yield: 0.23 g (20%). Melting point 238–239 °C. 1H
NMR (CDCl3): d 7.33 (m, 20H), 2.34 (m, 4H), 1.11
(m, 12H), 0.74 (m, 12H). 31P NMR (CDCl3): d 12.64
4. Supporting information available
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC, Nos. 239506–239508 for com-
pounds 2a–2c respectively. Copies of this information
may be obtained free of charge from: The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
(Fax: +44-1223-336033); e-mail: deposit@ccdc.cam.
3
3
(dd, JPP = 195 Hz, JPF = 13 Hz), ꢀ12.91 (dd,
3
3JPP = 195 Hz, JPF = 13 Hz). 19F NMR (C6D6): d
ꢀ84.32 (s). MS (EI): m/z = 714 (M+). Anal. Calc. for
C42H48F2P4: C, 70.58; H, 6.77. Found: C, 70.05; H,
6.92%.
3.2.5. 1,4-(PPh2)2-2,5-(PEt2)2-C6F2 (2c)
This was isolated analogously to 2b. Yield: 0.21 g
1
(21%). Melting point 198–200 °C. H NMR (CDCl3):
d 7.33 (m, 20H), 1.81 (m, 8H), 0.85 (m, 12H). 31P
Acknowledgement
3
NMR (CDCl3): d ꢀ11.48 (dm, JPP = 198 Hz), ꢀ12.41
3
(dm, JPP = 198Hz). 19F NMR (C6D6): d ꢀ88.44 (s).
We acknowledge generous financial support by Mich-
igan Technological University.
MS (EI): m/z = 658 (M+). Anal. Calc. for C38H40F2P4:
C, 69.30; H, 6.12. Found: C, 69.22; H, 6.47%.
3.3. X-ray crystallography
References
[1] F.A. Cotton, G. Wilkinson, C.A. Murillo, M. Bochman,
Advanced Inorganic Chemistry, John Wiley & Sons, New York,
1999.
In all cases, crystals were removed from the mother
liquor, coated with epoxy resin and placed on the head
of a thin glass fiber, which was anchored in a goiniom-
eter mounting pin. The pin-mounted crystal was then in-
serted into the goniometer head of the X-ray
[2] F.A. Cotton, B. Hong, Prog. Inorg. Chem. 40 (1992) 179.
[3] G. Jia, R.J. Puddephatt, J.D. Scott, J.J. Vittal, Organometallics
12 (1993) 3565.