Reactions of 1,1′-Bis(diphenylphosphino)ferrocene with Boranes, Thiaboranes, and Carboranes

Article abstract of DOI:10.1021/ic9611913

The reactions of 1,1′-bis(diphenylphosphino)ferrocene (dppf) with a variety of boranes, thiaboranes, and carboranes were found to produce a series of acid - base adducts or, in one case, a phosphonium salt. As confirmed by a single-crystal X-ray study, dppf reacted with BH₃·THF or nido-B₅H₉ to produce the complex dppf(BH₃)₂ (1) in which the two borane groups are coordinated directly to the phosphorus atoms of the dppf. Depending upon reaction stoichiometries, the reaction of dppf with nido-6-SB₉H₁₁ yielded arachno-9-(arachno-9′-dppf-6′-SB₉H ₁₁)-6-SB₉H₁₁ (2) or arachno-9-dppf-6-SB₉H₁₁ (3). Further reaction of 3 with BH₃·THF formed arachno-9-dppf-(BH₃)-6-SB₉H₁₁ (4). The reaction of nido-8-Me₂S-7-CB₁₀H₁₂ with dppf produced nido-8-dppf-7-CB₁₀H₁₂ (5), but the analogous reaction with nido-9-Me₂S-7,8-C₂B₉H₁₁ resulted in methyl transfer to dppf to produce the phosphonium salt [dppf-Me⁺][nido-9-MeS-7,8-C₂B₉H ₁₁^-] (6). Reactions of dppf with B₁₀H₁₄ produced both arachno-6,9-(dppf)₂B₁₀H₁₂ (7) and oligomeric [arachno-6,9-dppf-B₁₀H₁₂]_n (8) materials.

Full text of DOI:10.1021/ic9611913

Inorg. Chem. 1997, 36, 547-553
547
Reactions of 1,1′-Bis(diphenylphosphino)ferrocene with Boranes, Thiaboranes, and
Carboranes
Kelley J. Donaghy, Patrick J. Carroll, and Larry G. Sneddon*
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
ReceiVed September 27, 1996X
The reactions of 1,1′-bis(diphenylphosphino)ferrocene (dppf) with a variety of boranes, thiaboranes, and carboranes
were found to produce a series of acid-base adducts or, in one case, a phosphonium salt. As confirmed by a
single-crystal X-ray study, dppf reacted with BH3‚THF or nido-B5H9 to produce the complex dppf(BH3)2 (1) in
which the two borane groups are coordinated directly to the phosphorus atoms of the dppf. Depending upon
reaction stoichiometries, the reaction of dppf with nido-6-SB9H11 yielded arachno-9-(arachno-9′-dppf-6′-SB9H11)-
6-SB9H11 (2) or arachno-9-dppf-6-SB9H11 (3). Further reaction of 3 with BH3‚THF formed arachno-9-dppf-
(BH3)-6-SB9H11 (4). The reaction of nido-8-Me2S-7-CB10H12 with dppf produced nido-8-dppf-7-CB10H12 (5),
but the analogous reaction with nido-9-Me2S-7,8-C2B9H11 resulted in methyl transfer to dppf to produce the
phosphonium salt [dppf-Me+][nido-9-MeS-7,8-C2B9H11-] (6). Reactions of dppf with B10H14 produced both
arachno-6,9-(dppf)2B10H12 (7) and oligomeric [arachno-6,9-dppf-B10H12]n (8) materials.
shifts were measured relative to an external 85% H3PO4 standard (0.00
ppm) with negative values indicating upfield shifts. High- and low-
Introduction
The extensive recent investigations of the properties of 1,1′-
bis(diphenylphosphino)ferrocene (dppf) have now established
that it can strongly coordinate as either a mono- or bidentate
ligand to numerous transition metals, thus forming a range of
mono- and polymetallo complexes and oligomers.1 In this
paper, we report that dppf also forms a wide variety of strongly
bonded complexes with Lewis acidic boranes, thiaboranes, and
carboranes.
resolution mass spectra were obtained on a VG-ZAB-E high-resolution
mass spectrometer using negative-ion detection. IR spectra were
obtained on a Perkin-Elmer 1430 spectrometer. Elemental analyses
were performed at Robertson Microlit Laboratories. Molecular weight
distribution averages were determined by Dr. E. E. Remsen at
Monsanto, using size exclusion chromatography with in-line viscometric
detection (SEC/VISC).
dppf(BH3)2 (1) from BH3‚THF. To a two-neck flask fitted with
stirbar, septum, and nitrogen inlet were added 0.60 g (1.08 mmol) of
dppf and 25 mL of toluene. Under nitrogen, 5 mL of BH3‚THF (1 M
solution in THF) was added via syringe. TLC analysis in 50:50 CH2-
Cl2/hexane indicated all dppf had been consumed after 1 h. The solution
was then filtered through a short plug of silica gel and the solvent
vacuum-evaporated from the bright orange filtrate. The remaining solid
was flash chromatographed using 50:50 CH2Cl2/hexane as eluent to
afford 0.50 g (0.86 mmol, 80% yield) of bright orange dppf(BH3)2.
Further purification was effected by thin-layer chromatography on silica
gel using a 50:50 solution of CH2Cl2/hexane (Rf 0.67). For 1: mp
192-194 °C; IR (CCl4/NaCl plates) 3160 (w), 3140 (w), 2400 (s), 2360
(s), 2320 (s), 2220 (w), 1490 (m), 1450 (s), 1390 (w), 1380 (w), 1310
(w), 1200 (w), 1190 (m), 1180 (s), 1140 (w), 1110 (s), 1070 (m), 1060
Experimental Section
Materials. [arachno-6-SB9H12-][NMe4+],2 nido-8-Me2S-7-CB10H12,3
4
and nido-9-Me2S-7,8-C2B9H11 were prepared as previously reported.
Pentaborane(9), nido-B5H9, was obtained from laboratory stock. De-
caborane was obtained from Johnson Matthey or Callery Chemical and
sublimed before use. dppf was purchased from Aldrich and used as
received or flash-chromatographed in 50:50 CH2Cl2/hexane and
recrystallized from same. All solvents were of reagent grade and were
dried according to literature methods. Flash column chromatography
was performed as described by Still5 using Merck 60-200 mesh silica
gel and the indicated solvents. Preparative thin-layer chromatography
was conducted on 0.5 mm (20 × 20 cm) silica gel F-254 plates (Merck
5744). Analytical TLC was performed on 0.25 mm (2 × 4 cm) silica
gel F-254 plates (Merck).
Physical Methods. Proton, phosphorus-31, and boron-11 NMR
spectra at 200.1, 80.1, and 64.2 MHz, respectively, were obtained on
a Bruker WP-200 spectrometer. Proton, boron-11, and carbon-13 NMR
spectra at 500.1, 160.5, and 125.7 MHz, respectively, were obtained
on a Bruker AM-500 spectrometer. All boron-11 chemical shifts are
referenced to BF3‚OEt2 (0.00 ppm) with a negative sign indicating an
upfield shift. All proton chemical shifts were measured relative to
residual protons in the lock solvents and are referenced to tetrameth-
ylsilane (0.0 ppm) with positive values indicating downfield shifts.
Carbon-13 chemical shifts were measured relative to the carbons in
the lock solvents and are referenced to TMS. Phosphorus-31 chemical
(s), 1030 (s), 840 (s), 780 (m), 730 (s), 700 (s), 640 (s), 615 (s) cm-1
.
1
Exact mass measurement for 12C34 H3411B256Fe31P2, m/z: calcd, 582.1671;
found, 582.1683. Anal. Calcd for C34H34B2FeP2: C, 70.16; H, 5.89.
Found: C, 69.91; H, 5.83.
dppf(BH3)2 (1) from B5H9. To a one-piece flask fitted with stirbar
and Teflon stopcock was added 2.50 g (6.1 mmol) of dppf. THF (25
mL) and 0.39 g (6.1 mmol) of B5H9 were then added by vacuum
transfer. The orange-yellow solution was stirred at 0 °C for 4 h and
then allowed to react at room temperature overnight. Solvent and
excess B5H9 were vacuum-evaporated, and the resulting yellow glassy
solid was recrystallized using CH2Cl2/heptane to afford 1.57 g (2.70
mmol, 45% yield) of dppf(BH3)2 (1). The analytical and spectroscopic
data for the isolated product were identical to those described above.
arachno-9-(arachno-9′-dppf-6′-SB9H11)-6-SB9H11 (2). The litera-
ture method2 was used to prepare nido-6-SB9H11 by reaction of 0.86 g
(4.0 mmol) of [arachno-6-SB9H12-][NMe4+] with 0.51 g (2.0 mmol)
of I2 in 30 mL of toluene at 70 °C. After 2 h at reflux, the resulting
solution of nido-6-SB9H11 was filtered, and the filtrate was added to a
100 mL two-neck flask fitted with a reflux condenser, nitrogen inlet,
and stirbar which had already been charged with 0.55 g (1.0 mmol) of
dppf. According to TLC analysis, all dppf was consumed after
overnight reflux. The solution was then filtered and the solvent
X Abstract published in AdVance ACS Abstracts, January 15, 1997.
(1) Gan, K.-S.; Hor, T. S. A. In Ferrocenes; Togni, A., Hayashi, T., Eds.;
VCH: New York, 1995; Chapter 1, pp 3-104.
(2) Rudolph, R. W.; Pretzer, W. R. Inorg. Synth. 1983, 22, 226-231.
(3) Quintana, W.; Sneddon, L. G. Inorg. Chem. 1990, 29, 3242-3245.
(4) Plesˇek, J.; Janousˇek, Z.; Heˇrma´nek, S. Collect. Czech. Chem. Commun.
1978, 43, 2862-2868.
(5) Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2923-
2925.
S0020-1669(96)01191-3 CCC: $14.00 © 1997 American Chemical Society

548 Inorganic Chemistry, Vol. 36, No. 4, 1997
Table 1. NMR Dataa
Donaghy et al.
compound
nucleus
δ (multiplicity, J (Hz), assignment)
dppf(BH3)2 (1)
11B{1H}b -38.7 (br s)
1Hc
7.45 (m, 20, Ph), 4.53 (s, 4, Cp), 4.25 (s, 4, Cp), 1.12 (d, 3, 2JPH 20,d BH)
13C{1H}e 132.5 (d, JCP 10, Ph), 131.1 (s, Ph), 130.9 (d, JCP 55, Ph), 128.5 (d, JCP 10, Ph), 74.5 (d, JCP 7,
Cp), 73.9 (d, JCP 9.5, Cp), 70.5 (d, JCP 64.8, Cp)
31P{1H}f
16.5 (br)
arachno-9-(arachno-9′-dppf-6′-SB9H11)-
6-SB9H11 (2)
11Bg
6.7 (d, 1, JBH 120), -5.2 (br, 1), -8.3 (br, 2), -25.8 (d of d, 1, JBP 105h), -31.0 (d, 2, JBH 117),
-36.1 (d, 2, JBH 145)
1Hi
7.51 (m, 20, Ph), 4.60 (s, 4, Cp), 4.39 (s, 4, Cp), -1.6 (br, 1, µBHB)
13C{1H}e 133.4 (d, JCP 9, Ph), 132.4 (d, JCP 2, Ph), 128.9 (d, JCP 11, Ph), 127.0 (d, JCP 70, Ph), 74.9 (d,
JCP 8, Cp), 74.8 (d, JCP 10, Cp), 70.3 (d, JCP 76, Cp)
31P{1H}f
9.45 (m, J ∼104)
arachno-9-dppf-6-SB9H11 (3)
11Bg
6.9 (d, 1, JBH 124), -5.5 (br, 1), -8.2 (br, 2), -25.2 (d of d, 1), -30.9 (d, 2, JBH 113), -36.1 (d,
2, JBH 145)
1Hi
7.70-7.30 (m), 7.25 (s, 20, Ph), 4.52 (s, 2, Cp), 4.40 (s, 2, Cp), 4.21 (s, 2, Cp), 4.16 (s, 2, Cp),
-1.24 (br, 2, µBHB)
13C{1H}e 138.5 (d, JPC 11, Ph), 133.6 (d, JPC 3, Ph), 133.4 (d, JPC 14, Ph), 132.1 (d, JPC 3, Ph), 128.8 (d,
JPC 17, Ph), 128.6 (d, JPC 15, Ph), 128.5 (d, JPC 18, Ph), 128.4 (d, JPC 38, Ph), 127.4 (d, JPC 70,
Ph), 78.9 (d, JPC 11, Cp), 74.9 (d, JPC 14, Cp), 74.6 (d, JPC 10, Cp), 74.1 (d, JPC 8, Cp), 72.8 (d,
JPC 3.5, Cp), 68.3 (d, JPC 79, Cp)
31P{1H}f
9.4 (br, 1), -18.4 (s, 1)
arachno-9-dppf(BH3)-6-SB9H11 (4)
11Bg
6.6 (d, 1, JBH 133), -5.3 (s, 1), -8.4 (br s, 2), -25.7 (d of d, 1, JBP ∼100),h -30.1 (d, 2, JBH 128),
-36.2 (d, 2, JBH 146), -39.0 (s, 1, BH3)
1Hi
7.5 (m, 20, Ph), 4.59 (s, 2, Cp), 4.41 (s, 4, Cp), 4.27 (s, 2, Cp), -1.5 (br, 1, µBHB)
13C{1H}e 133.5 (d, JCP 9, Ph), 132.5 (d, JCP 9, Ph), 132.2 (d, JCP 2, Ph), 131.3 (d, JCP 10, Ph), 130.5 (d,
JCP 60, Ph), 128.7 (d, JCP 10, Ph), 128.6 (d, JCP 69.7 Ph), 127.2 (d, JCP 70, Ph), 75.1 (d, JCP 9,
Cp), 74.6 (d, JCP 10, Cp), 74.3 (d, JCP 8, Cp), 74.1 (d, JCP 10, Cp), 71.6 (d, JCP 66, Cp),
69.4 (d, JCP 76, Cp)
31P{1H}f
16.7 (br, 1), 10.7 (br m, 1, JPB ∼130)
nido-8-dppf-7-CB10H12 (5)
11Bg
1.6 (d, 1, JBH 132), -8.5 (d, 1, JBH 143), -11.0 (br, 2), -10.8 (br, 1), -19.6 (d, 1, JBH 110),
-24.3 (d, 1, JBH ∼100), -25.1 (d, 1, JBH 139), -27.8 (d, 1, JBH 138), -28.6 (d, 1, JBH 140)
7.9-7.4 (m, 20, Ph), 4.63 (s, 2, Cp), 4.45 (s, 1, Cp), 4.40 (s, 1, Cp), 4.35 (s, 1, Cp), 4.27 (s, 1,
Cp), 4.18 (s, 1, Cp), 4.07 (s, 1, Cp), 1.78 (s, 1, CH), -2.6 (br, 1, µBHB), -3.5 (br, 1, µBHB)
1Hi
13C{1H}e 138.2 (d, JCP 10, Ph), 137.9 (d, JCP 10, Ph), 133.8 (d, JCP 10, Ph), 133.5 (d, JCP 9, Ph), 133.4 (d,
JCP 9, Ph), 133.4 (d, JCP 6, Ph), 133.3 (d, JCP 8, Ph), 133.0 (d, JCP 3, Ph), 132.5 (d, JCP 10, Ph),
129.3 (d, JCP 12, Ph), 129.1 (d, JCP 11, Ph), 128.9 (s, Ph), 128.5 (d, JCP 7, Ph), 128.4 (d, JCP 9,
Ph), 128.3 (d, JCP 7, Ph), 124.9 (d, JCP 74, Ph), 123.9 (d, JCP 75, Ph), 75.6 (d, JCP 9, Cp),
75.1 (d, JCP 9, Cp), 74.9 (d, JCP 15, Cp), 74.8 (d, JCP 12, Cp), 74.2 (d, JCP 9, Cp), 73.6 (d,
JCP 9, Cp), 73.4 (d, JCP 75, Cp), 65.8 (d, JCP 83, Cp), 38.4 (cage CH)
31P{1H}f
3.9 (m, 1, JPB ∼160 Hz), -17.6 (1)
[dppf-Me+][nido-9-SMe-7,8-C2B9H11-] (6) 11Bg
0.54 (s, 1), -10.7 (d, 1, JBH 192), -14.3 (d, 1, JBH 128), -18.6 (d, 1, JBH 176), -21.9 (d, 1,
J
BH 128), -23.6 (d, 1, JBH 208), -24.7 (d, 1, JBH 144), -32.9 (d, 1, JBH 144), -38.7 (d, 1,
JBH 144)
1Hi
7.82-7.28 (m, 20, Ph), 4.77 (s, 2, Cp), 4.41 (s, 4, Cp), 4.19 (s, 2, Cp), 2.64 (d, 3, PMe+, JPCH 13),
2.21 (s, 1, CH), 2.07 (s, 3, SMe), 1.71 (s, 1, CH), -2.52 (br, µBHB)
13C{1H}e 137.7 (d, JCP 8, Ph), 135.2 (d, JCP 3, Ph), 133.5 (d, JCP 20, Ph), 132.2 (d, JCP 11, Ph), 130.4 (d,
J
CP 13, Ph), 129.2 (s), 128.6 (d, JCP 5, Ph), 120.8 (d, JCP 91, Ph), 76.2 (d, JCP 11, Cp), 75.2 (d,
CP 13, Cp), 73.6 (d, JCP 13, Cp), 73.4 (s, Cp), 60.4 (d, JCP 104, Cp), 49.1 (br s, cage CH),
J
36.5 (br s, cage CH), 16.1 (s, SC), 9.78 (s, JCP 60, PC)
23.41(s, 1), -18.31 (br)
31P{1H}f
arachno-6,9-(dppf)2-B10H12 (7)
11Bb
-6.0 (d, 2, JBH 141), -12.0 (d, 2, JBH 132), -28.5 (d, 2, JBH 137), -37.3 (br, 2),j -51.5 (d, 2,
JBH 148)
1Hc
7.6-7.4 (m, 40, Ph), 4.65 (s, 1, Cp), 4.63 (s, 1, Cp), 4.40 (s, 2, Cp), 4.39 (s, 1, Cp), 4.28 (s, 2, Cp),
3.97 (s, 1, Cp), -2.5 (br, 2, µBHB)
13C{1H}e,k Ph region: 133.4, 133.3, 133.2, 133.2, 132.5, 132.5, 132.5, 132.4, 132.4, 132.1, 131.2, 131.1,
131.0, 130.8, 130.3, 128.8, 128.7, 128.6, 128.6, 128.5, 128.4, 128.2, 128.1
Cp region: 75.5, 75.4, 74.7, 74.7, 74.6, 74.5, 74.5, 74.3, 74.3, 74.2, 74.0, 73.9, 73.6, 73.5, 73.2
31P{1H}f
15.2 (br s), -17.7 (s)
[6,9-dppf-B10H12]n (8)
11B{1H}b,j -3.3, -16.5, -36.8
1Hc
7.4 (m, Ph), 4.6 (s, Cp), 4.5 (s, Cp), 4.4 (s, Cp), 4.3 (s, Cp), -3.78 (br, µBHB)
∼15, ∼9 (br)
31P{1H}f
d
2
h
a CD2Cl2 solvent. b 64.1 MHz. c 200.1 MHz. JPH was determined in the 1H{11B}NMR spectrum. e 125.8 MHz. f 80.1 MHz. g 160.5 MHz. JBP
was determined from 11B{1H} NMR spectra. i 500.1 MHz. j Broad and unstructured; therefore, JBH values were unobtainable. k Due to the extent
of overlapping peaks, no JCP values were assignable; peaks were recorded individually.
vacuum-evaporated from the yellow filtrate. The remaining yellow
oil was flash-chromatographed using 70:30 CH2Cl2/hexane (TLC Rf
0.60, 70:30 CH2Cl2/hexane) to yield 0.18 g (0.20 mmol, 21% yield
based on consumed dppf) of arachno-9-(arachno-9′-dppf-6′-SB9H11)-
6-SB9H11 (2) as a yellow solid. For 2: mp >300 °C dec; IR (NaCl,
CCl4) 2520 (vs), 1480 (m), 1430 (s), 1390 (w), 1370 (w), 1310 (w),
1200 (w), 1180 (m), 1170 (m), 1160 (w), 1100 (m), 1050 (w), 1030
(m), 1005 (m, br), 940 (m), 910 (m), 830 (m), 790 (m), 740 (m), 730
(m), 710 (m), 690 (m), 650 (w), 620 (w), 600 (vw), 550 (w), 510 (w),
495 (m), 480 (m), 470 (m, br), 420 (w), 410 (w) cm-1. Anal. Calcd
for C34H50B18FeP2S2‚CH2Cl2: Anal. Calcd: C, 45.68; H, 5.70.
Found: C, 45.83; H, 5.66.
of toluene at 70 °C. After being heated at reflux for 2 h, the solution
was filtered and the filtrate reacted as described above with 2.22 g
(4.0 mmol) of dppf for 20 h. Purification by column chromatography
on silica gel, using 30:70 CH2Cl2/hexane as eluent (Rf 0.24), produced
2.31 g (3.32 mmol), 44% yield, of arachno-9-dppf-6-SB9H11 as a yellow
solid. For 3: mp 102-104 °C; IR (KBr pellet) 3010 (w), 2900 (m,
sh), 2820 (w), 2520 (s), 1430 (s), 1380 (w), 1200 (vw), 1170 (w), 1100
(m), 1020 (m), 1000 (m), 920 (w), 910 (w), 820 (w), 790 (vw), 730
(s), 690 (s), 530 (w), 480 (m) cm-1
. Exact mass measurement for
12
C
1H3811B932S31P256Fe, (P - 1), m/z: calcd, 695.2356; found,
34
695.2370. Anal. Calcd for C34H39B9SP2Fe: C, 58.77; H, 5.66.
Found: C, 58.71; H, 5.72.
arachno-9-dppf-6-SB9H11 (3). Using the method2 described above,
nido-6-SB9H11 was prepared by the reaction of 1.8 g (8.3 mmol) of
[arachno-6-SB9H12-][NMe4+] with 1.05 g (4.1 mmol) of I2 in 100 mL
arachno-9-dppf(BH3)-6-SB9H11 (4). A 25 mL two-neck flask fitted
with a stirbar, septum, and nitrogen inlet was charged with 0.25 g (0.35
mmol) of 3 and 15 mL of toluene. The reaction mixture was purged

Reactions of 1,1′-Bis(diphenylphosphino)ferrocene
Inorganic Chemistry, Vol. 36, No. 4, 1997 549
with nitrogen, and a 1 mL aliquot of 1 M BH3‚THF in THF was added
via syringe. According to TLC analysis, all of 3 was consumed after
2 h. The reaction mixture was then filtered in air through silica gel,
and the solvent vacuum-evaporated from the filtrate. The resulting oil
was flash-chromatographed (50:50 CH2Cl2/hexane) to afford 0.25 g
(0.35 mmol, >99% yield) of arachno-9-dppf(BH3)-6-SB9H11 as a
yellow solid. For 4: mp 150-151 °C; IR (NaCl, CCl4) 3050 (w),
2560 (s), 2400 (m), 2330 (w), 1480 (w), 1435 (s), 1390 (w), 1310 (w),
1190 (m, sh), 1170 (m), 1105 (m), 1060 (m), 1030 (m), 1010 (m, sh),
930 (w), 910 (w), 835 (w), 800 (vw), 740 (s), 690 (s), 625 (w), 610
Table 2. Data Collection and Structural Refinement Information
for 1 and 3
a
formula
fw
FeC34B2H34P2
582.06
FeC35H41P2SB9Cl2
779.76
crystal class
space group
Z
triclinic
P1h (No. 2)
1
monoclinic
P21/c (No. 14)
4
cell constants
a (Å)
b (Å)
9.1516(4)
10.3214(6)
8.7133(4)
113.481(4)
90.826(3)
86.252(3)
753.21(7)
6.28
13.0289(5)
11.3930(5)
26.683(1)
c (Å)
(w), 480 (m) cm-1
. Anal. Calcd for C34H42B10FeP2S‚CH2Cl2: C,
52.97; H, 5.59. Found: C, 52.98; H, 5.55.
R (deg)
â (deg)
γ (deg)
V (Å3)
92.061(2)
nido-8-dppf-7-CB10H12 (5). A 100 mL one-piece flask fitted with
a stirbar and high-vacuum stopcock was charged with 0.50 g (2.5 mmol)
of nido-8-Me2S-7-CB10H12, 1.50 g (2.7 mmol) of dppf, and 30 mL of
dry toluene. The mixture was heated for 12 h at 85 °C with periodic
degassing. Following filtration and solvent evaporation, the product
was purified by flash chromatography on silica gel using 50:50 CH2-
Cl2/hexane as eluent to provide 0.60 g (0.87 mmol, 35% yield) of the
yellow product, 5. For 5: mp 201-203 °C; IR (CCl4, NaCl) 3200
(w), 2980 (w), 2960 (w), 2520 (vs), 1590 (w), 1550 (w), 1470 (m),
1440 (s), 1390 (w), 1360 (w), 1310 (w), 1260 (w), 1200 (w), 1180
3958.2(2)
6.75
µ (cm-1
)
crystal size, mm
0.47 × 0.12 × 0.060 0.56 × 0.08 × 0.06
D
calc (g/cm3)
1.283
1.308
F(000)
304
401
radiation (λ (Å)
Mo KR (0.7107)
2.0-25.0
+10,(12,(10
5906
Mo KR (0.7107)
4.0-49.5
0,(15,(31
28 259
6867 (0.0642)
4392 (F2 > 3.0σ)
401
θ range (deg)
h,k,l collected
no. of reflns measd
no. of unique reflns (Rmerge
no. of reflns used in refinmt 1884
no. of params
)
2393 (0.033)
(m), 1100 (s), 1040 (m), 1010 (m), 980 (w) cm-1
.
Exact mass
B
31P256Fe (P - 2H), m/z: calcd, 686.2729;
10
246
1
11
measurement for 12C35 H38
data/param ratio
R1
R2
GOF
7.66
0.034
0.037
1.74
11.0
0.115
0.1211
5.07
found, 686.2716. Anal. Calcd for C35H40B10P2Fe: C, 61.23; H, 5.87;
Found: C, 63.75, H, 5.94.
[dppf-Me+][nido-9-MeS-7,8-C2B9H11-] (6). A 100 mL one-piece
flask fitted with a stirbar and high-vacuum stopcock was charged with
0.55 g (2.8 mmol) of nido-9-Me2S-7,8-C2B9H11, 1.50 g (2.80 mmol)
of dppf, and ∼20 mL of toluene. The reaction mixture was stirred at
80 °C for 61 h with periodic degassing. Separation of the product
mixture by flash chromatography on silica gel using 100% CH2Cl2 as
eluent gave 1.05 g (1.76 mmol, 52% yield) of a thermally unstable
orange oil that was then stored at -78 °C to avoid decomposition. For
6: IR (KBr Pellet) 3030 (m), 2930 (s, sh), 2840 (s), 2530 (vs), 1780
(w), 1720 (s), 1690 (w), 1590 (w), 1570 (m), 1440 (vs), 1400 (w),
1370 (w), 1310 (w), 1280 (w), 1190 (s, sh), 1170 (s), 1100 (s), 1040
(s), 1010 (s), 1000 (s), 940 (m), 920 (m), 840 (m), 800 (s), 750 (s),
a The crystals of 3 were found to contain less than equivalent amounts
of CH2Cl2.
500 (s), 440 (w) cm-1. Anal. Calcd for C34H40B10FeP2: C, 60.54; H,
5.98. Found: C, 59.49; H, 5.91.
Crystallographic Studies of 1 and 3. Single crystals of 1 and 3
were grown by slow evaporation of CH2Cl2/heptane solutions under
N2.
(a) Collection and Reduction of the Data. X-ray intensity data
for 1 and 3 were collected on a MSC/RAXIS IIc area detector
employing graphite-monochromated Mo KR radiation (λ ) 0.7107 Å)
at a temperature of 233-5 K. Indexing was performed from a series
of 1° oscillation images with exposures of either 5 min (1) or 10 min
(3) per frame. Data were collected using 6° oscillation angles with
exposures of 10 min per frame and a crystal-to-detector distance of 82
mm. Oscillation images were processed using bioteX,6 producing a
listing of unaveraged F2 and σ(F2) values which were then passed to
the teXsan7 program package for further processing and structure
solution and refinement on a Silicon Graphics Indigo R4000 computer.
The intensity data were corrected for Lorentz and polarization effects,
but not for absorption.
(b) Solution and Refinement of the Structures. The structures
were solved by direct methods (SIR922). Refinement was accomplished
by full-matrix least-squares techniques based on F to minimize the
quantity ∑w(|Fo| - |Fc|)2 with w ) 1/σ2(F). For 1, non-hydrogen atoms
were refined anisotropically and hydrogen atoms were refined isotro-
pically. For 3, CH2Cl2 was found to be present in less than
stoichiometric amounts. In addition, the SB9 cage was found to be
disordered by a rotation about the P1-B1 bond. A satisfactory disorder
model was not devised; thus the S and B atoms were only refined
isotropically. All other non-hydrogen atoms were refined anisotropi-
cally, and hydrogen atoms were included as constant contributions to
the structure factors and were not refined.
1
730 (s), 700 (m) cm-1. Although the H, 11B, and 13C NMR spectra
(Supporting Information) indicated that 6 could be initially isolated in
excellent purity, repeated attempts at microanalysis did not give
satisfactory results, with the best analysis being the following. Anal.
Calcd for C38H45B9P2FeS: C, 60.94; H, 6.06. Found: C, 55.63; H,
7.85.
arachno-6,9-(dppf)2B10H12 (7). A 100 mL two-neck flask fitted
with a reflux condenser, N2 inlet, and stirbar was charged with 2.77 g
(5.0 mmol) of dppf and 60 mL of CH2Cl2. A solution containing 1.00
g (8.0 mmol) of B10H14 dissolved in 20 mL of CH2Cl2 was added via
syringe and the mixture stirred at room temperature. As evidenced by
TLC analysis, the reaction was near completion within 2 h. Purification
by thin-layer chromatography on silica gel using 50:50 CH2Cl2/hexane
as eluent (Rf 0.52) gave 0.31 g (0.40 mmol, 5% yield) of arachno-
6,9-(dppf)2B10H12. Remaining at the baseline of the TLC separation
were large amounts of oligomeric materials (see below). For 7: mp
90-94 °C; IR (KBr pellet) 3200 (w, br), 2510 (s), 2380 (s, sh), 1480
(m), 1430 (s), 1380 (w), 1330 (vw), 1320 (w), 1250 (vw), 1190 (m),
1180 (m), 1100 (s), 1050 (m), 1030 (m), 990 (w), 920 (w), 835 (m),
735 (s) cm-1. Anal. Calcd for C68H68B10Fe2P4: C, 66.46; H, 5.58.
Found: C, 64.50; H, 5.84.
[6,9-dppf-B10H12]n (Oligomer) (8). To a 150 mL, two-neck flask
were added 1.00 g (8.06 mmol) of B10H14, 4.50 g (8.12 mmol) of dppf,
and 75 mL of CH2Cl2. The reaction mixture was flushed with N2 and
stirred at ∼50 °C overnight. Following filtration and solvent evapora-
tion, the resulting solid was dissolved in CH2Cl2 and the concentrated
solution poured into pentane. The cloudy solution was filtered, the
precipitate was redissolved in CH2Cl2, the resulting solution was poured
into pentane. This procedure was repeated twice, and the resulting
peach-colored material was dried in Vacuo to afford 3.58 g (65% yield)
of product. For 8: mp >300 °C; Mn ) 1670, Mw ) 2660, Mz ) 6604;
IR (NaCl, CCl4) 3250 (w), 3090 (w), 2520 (s), 2470 (m), 1500 (m),
1450 (s), 1410 (w), 1330 (w), 1180 (w), 1100 (m), 1050 (m), 1020
(m), 1000 (w), 930 (m), 850 (w), 810 (w), 760 (m), 710 (s), 670 (w),
Results and Discussion
Many boranes, carboranes, and thiaboranes are sufficiently
acidic to form strong adducts with Lewis bases, with the simplest
examples being the borane adducts of the formula, BH3‚L.8
(6) Chen, D.; Day, C. L.; Ferrara, J. D.; Higashi, T. L.; Pflugrath, J. W.;
Santarsiero, B. D.; Swepston, P. N.; Troup, J. M.; Vincent, B. R.;
Xiong, L. bioteX: A Suite of Programs for the Collection, Reduction
and Interpretation of Imaging Plate Data; Molecular Structure
Corp.: The Woodlands, TX 77381, 1995.
(7) teXsan: Single Crystal Structure Analysis Software, Version 1.7;
Molecular Structure Corp.: The Woodlands, TX 77381, 1995.

550 Inorganic Chemistry, Vol. 36, No. 4, 1997
Donaghy et al.
Figure 2. Alternate view of the structure of dppf(BH3)2, 1, showing
the staggered anti arrangement of the cyclopentadienyl rings.
Figure 1. ORTEP plot of the structure of dppf(BH3)2, 1.
Table 3. Refined Positional Parameters for dppf(BH3)2, 1
boron atom is displaced 0.25 Å out of this plane toward the
iron. Thus, the dihedral angle between the plane of the
cyclopentadienyl ring and the C1-P1-B1 plane is 10.6°. The
angles around the phosphorus (average C-P-C 105.9°; average
C-P-B 112.8°) and boron atoms (average P-B-H 105°;
average H-B-H 114°) are approximately tetrahedral. The
boron-Fe distance is greater than 5 Å.
atom
x
y
z
Beq (Å2)
1
1
1
Fe1
P1
C1
C2
C3
C4
C5
C6
C7
/
/
/
2
2.19(2)
2.30(3)
2.1(1)
2.7(1)
3.3(1)
3.5(1)
2.8(1)
2.6(1)
3.3(1)
4.2(2)
5.1(2)
5.0(2)
3.8(2)
2.7(1)
2.9(1)
3.9(2)
5.0(2)
6.0(2)
4.8(2)
3.5(2)
2
2
0.26882(7)
0.3288(3)
0.2805(3)
0.3589(4)
0.4553(4)
0.4373(3)
0.2522(3)
0.3519(4)
0.3473(4)
0.2432(5)
0.1420(5)
0.1442(4)
0.0816(3)
0.0128(3)
-0.1289(4)
-0.2003(4)
-0.1345(4)
0.0063(4)
0.3917(4)
0.30187(8)
0.4676(3)
0.5517(3)
0.6766(3)
0.6701(3)
0.5434(3)
0.1895(3)
0.0746(3)
-0.0100(4)
0.0194(4)
0.1322(5)
0.2172(4)
0.3365(3)
0.4700(4)
0.4881(5)
0.3740(6)
0.2428(6)
0.2204(4)
0.2198(5)
0.19210(9)
0.3371(3)
0.5050(4)
0.5640(4)
0.4367(4)
0.2974(4)
0.3047(4)
0.2728(4)
0.3604(5)
0.4828(5)
0.5151(5)
0.4256(4)
0.1413(3)
0.1922(4)
0.1406(4)
0.0403(5)
-0.0093(6)
0.0396(5)
-0.0046(5)
The NMR data for 1 are consistent with the solid state
structure. The 11B NMR spectrum shows one broad resonance
at a shift (-38.7 ppm) similar to those of other simple
phosphine-borane adducts (e.g., for PPh3‚BH3, -37.5 ppm).11
C8
C9
1
The H NMR spectrum contains a phenyl multiplet and two
C10
C11
C12
C13
C14
C15
C16
C17
B1
intensity 4 resonances, at 4.53 and 4.25 ppm, attributed to the
two sets of Cp protons. The resonance due to the three BH
protons at 1.12 ppm is very broad owing to coupling to both
boron and phosphorus but upon boron decoupling sharpens to
2
a doublet with JPH ) 20 Hz. The 13C NMR spectrum shows
the phenyl resonances between 132 and 128 ppm and three
cyclopentadienyl resonances between 76 and 70 ppm. The
carbon resonances exhibit phosphorus coupling with the largest
JCP observed for the carbon bound directly to the phosphorus.
The JCP values are somewhat larger than those found for the
parent dppf, consistent with the four-coordination of the
phosphorus in 1.12 The 31P NMR spectrum shows only a single
broad resonance, consistent with the complexation of both
phosphorus atoms, at a shift (16.5 ppm) that is similar to that
found for Ph3P‚BH3 (20.7 ppm)11 but downfield from that found
for dppf (-17.2 ppm).1
Accordingly, the reaction of 2 equiv of BH3‚THF with dppf
(eq 1) gave the bis(borane) complex dppf(BH3)2, 1, which was
dppf(BH )
2BH3‚THF + dppf f
3 2 + 2THF
(1)
1
isolated as air-stable yellow needles in 80% yield by column
and plate chromatography.
As shown in the ORTEP drawing in Figure 1, a single-crystal
X-ray determination confirmed the two borane groups are
phosphorus-coordinated, with a B-P length of 1.922(4) Å
comparable to that found in PMe3‚BH3 (1.93(1) Å).9 The iron
atom lies on a crystallographic inversion center; thus the two
cyclopentadienyl rings are parallel, with an Fe to ring centroid
distance of 1.658 Å. As is found in the structure of the parent
dppf complex,10 the two cyclopentadienyl rings in 1 have a
staggered configuration with the substituents oriented in an anti
configuration, as shown in Figure 2. The phosphorus atom lies
0.049 Å above the plane of the cyclopentadienyl ring, but the
Pentaborane, B5H9, reacts with many phosphines to yield,
depending upon the phosphine and reaction conditions, adducts,
hypho-(R3P)2B5H9, and/or cleavage products including, B3H5‚-
3PR3, B2H4‚2PR3, and R3P‚BH3.13 Reactions of B5H9 with the
diphosphines bis(diphenylphosphino)methane (dppm) and bis-
(diphenylphosphino)ethane (dppe) are reported to yield air-stable
hypho-(dppm)B5H9 and hypho-(dppe)B5H9 adducts in which the
diphosphine ligands bridge the apical and basal positions of the
hypho-pentaborane framework.13f,g The reaction (eq 2) of
pentaborane with dppf, however, produced only 1, in 45% yield
along with intractable decomposition products. Even when
(8) See, for example: (a) Coyle, T. D.; Stone, F. G. A. Prog. Boron Chem.
1964, 1, 83. (b) Parshall, G. W. In The Chemistry of Boron and its
Compounds; Muetterties, E. L., Ed.; Wiley: New York, 1967; Chapter
9, pp 617-646. (c) No¨th, H. Prog. Boron Chem. 1970, 3, 213-223.
(9) Huffman, J. C.; Skupinski, W. A.; Caulton, K. G. Cryst. Struct.
Commun. 1983, 11, 1435.
(11) Durand, M.; Jouany, C.; Jugie, G.; Elegant, L.; Gal, J.-F. J. Chem.
Soc., Dalton Trans. 1977, 57-60.
(12) (a) Tebby, J. C. In Phosphorus-31 NMR Spectroscopy in Stereochem-
ical Analysis: Organic Compounds and Metal Complexes; Verkade,
J. G., Quin, L. D., Eds.; VCH: Deerfield Beach, FL, 1987; Chapter
1, pp 1-60. (b) Silverstein, R. M.; Bassler, G. C.; Morrill, T. C.
Spectrometric Identification of Organic Compounds, 4th ed.; Wiley:
New York, 1981; p 275.
(10) Casellato, U.; Ajo´, D.; Valle, G.; Corain, B.; Longato, B.; Graziani,
R. J. Crystallogr. Spectrosc. Res. 1988, 18, 583-590.

Reactions of 1,1′-Bis(diphenylphosphino)ferrocene
Inorganic Chemistry, Vol. 36, No. 4, 1997 551
Table 4. Selected Bond Distances (Å) and Angles (deg) for dppf(BH3)2, 1
Fe1-C1
Fe1-C4
P1-C6
2.051(2)
2.056(3)
1.806(3)
1.430(4)
1.405(5)
1.387(4)
1.378(6)
1.393(4)
1.349(6)
1.089(32)
Fe1-C2
Fe1-C5
P1-C12
C1-C5
2.041(3)
2.053(3)
1.812(3)
1.430(4)
1.403(4)
1.373(5)
1.387(5)
1.392(4)
1.385(5)
1.083(31)
Fe1-C3
P1-C1
2.050(3)
1.790(3)
1.922(4)
1.422(4)
1.385(4)
1.368(6)
1.378(4)
1.357(5)
1.117(32)
P1-B1
C1-C2
C2-C3
C6-C7
C8-C9
C12-C13
C14-C15
B1-H15
C3-C4
C4-C5
C6-C11
C9-C10
C12-C17
C15-C16
B1-H16
C7-C8
C10-C11
C13-C14
C16-C17
B1-H17
C1-P1-C6
107.6(1)
103.9(1)
103.5(17)
113.1(24)
C1-P1-C12
C6-P1-B1
P1-B1-H16
H15-B1-H17
106.3(1)
114.3(2)
106.0(17)
114.7(22)
C1-P1-B1
112.5(2)
111.7(2)
106.2(16)
112.3(22)
C6-P1-C12
P1-B1-H15
H15-B1-H16
C12-P1-B1
P1-B1-H17
H16-B1-H17
reactions were monitoried by NMR, there was no evidence of
any other soluble products.
dppf(BH )
3 2 + “B3H3”
B5H9 + dppf f
(2)
1
The polyhedral thiaborane nido-6-SB9H11 is strongly Lewis
acidic and is known to form strong arachno-9-L-6-SB9H11
complexes with many bases.14 It was likewise found that,
depending upon the reaction stoichiometry and conditions, the
reaction of nido-6-SB9H11 with dppf in refluxing toluene
produced the mono- and bisadducts of dppf.
Figure 3. Proposed structure of arachno-9-(arachno-9′-dppf-6′-
SB9H11)-6-SB9H11, 2.
2nido-6-SB9H11 + dppf f
arachno-9-(arachno-9′-dppf-6′-SB9H11)-6-SB9H11
resonances (two Ph resonances and two Cp resonances) exhibit-
ing the >60 Hz carbon-phosphorus coupling characteristic of
direct attachment of the carbon to a phosphorus.12 The 31P NMR
spectrum exhibits a sharp resonance (-18.4 ppm) in the dppf
region, indicative of an uncoordinated phosphorus, and one
broad resonance (9.4 ppm) near the shift observed for the
phosphorus coordinated by the thiaborane cage of 2.
(3)
2
arachno-9-dppf-6-SB H
nido-6-SB9H11 + dppf f
(4)
9
11
3
Both compounds were easily purified by flash column
chromatography, and their compositions are consistent with their
elemental analyses. In agreement with the structure proposed
in Figure 3, the 160.5 MHz 11B NMR spectrum of 2 consists
of six resonances of relative intensities 1:1:2:1:2:2 at chemical
shifts typical of those found for arachno-9-L-6-SB9H11 com-
pounds.14 The intensity 1 resonance (B9) at -25.8 ppm exhibits
phosphorus coupling, indicating its attachment to the dppf. The
1H NMR spectrum shows, in addition to the resonances arising
from the phenyl and cyclopentadienyl protons, one bridge
hydrogen resonance of intensity 2 at -1.6 ppm. The 13C NMR
spectrum of 2 is similar to that of 1, and its 31P NMR spectrum
consists of only one broad resonance at 9.45 ppm, which is
again shifted downfield relative to that of the parent dppf.
The 11B NMR spectrum of 3 is similar to that of 2, but its
1H NMR spectrum differs because of its inequivalent cyclo-
pentadienyl groups. Thus, the spectrum contains, in addition
to the bridge hydrogen resonance of intensity 2 at -1.24 ppm,
a complicated multiplet for the phenyl protons and four separate
singlet resonances of intensity 2 arising from the cyclopenta-
dienyl protons. Likewise, its 13C NMR spectrum shows four
Although disorder problems prevented a satisfactory refine-
ment, a single crystal X-ray study confirmed the structure
proposed for 3, as shown in the ORTEP drawing given in Figure
4. Unfortunately, the SB9 cage was found to be disordered by
a rotation about the P1-B1 bond. A satisfactory disorder model
was not devised; thus the sulfur and boron atoms were only
refined isotropically. All other non-hydrogen atoms were
refined anisotropically. While the distances and angles from
this determination must be considered unreliable, several gross
features regarding the structure are evident. In agreement with
the spectral data and previous structural studies of arachno-9-
L-6-SB9H11 complexes,14c the dppf is found to be coordinated
at the 9-boron position in 3. The two cyclopentadienyl rings
of the dppf have a dihedral angle of only 3.5° and are nearly
eclipsed, with the two phosphine substituents oriented such that
the P1-C-Fe and P2-C-Fe planes form a dihedral angle of
135° rather than the staggered anti (i.e., 180°) orientation found
in 1.
Compound 3 reacts (eq 5) with BH3‚THF to give the mixed
adduct arachno-9-dppf(BH3)-6-SB9H11, 4, in quantitative yields.
The elemental analyses are in excellent agreement with the
crystallization of 4 with 1 equiv of the CH2Cl2 solvent.
(13) (a) Savory, C. G.; Wallbridge, M. G. H. J. Chem. Soc., Dalton Trans.
1973, 179-184. (b) Fratini, A. V.; Sullivan, G. W.; Denniston, M.
L.; Hertz, R. K.; Shore, S. G. J. Am. Chem. Soc. 1974, 96, 3013-
3015. (c) Kameda, M.; Kodama, G. Inorg. Chem. 1980, 19, 2288-
2292. (d) Kameda, M.; Kodama, G. Inorg. Chem. 1987, 26, 2011-
2012. (e) Schwarz, A.; Kodama, G. Inorg. Chem. 1993, 32, 3970-
3972. (f) Alcock, N. W.; Colquhoun, H. M.; Haran, G.; Sawyer, J.
F.; Wallbridge, M. G. H. J. Chem. Soc., Dalton Trans. 1982, 2243-
2255. (g) Alcock, N. W.; Colquhoun, H. M.; Haran, G.; Sawyer, J.
F.; Wallbridge, M. G. H. J. Chem. Soc., Chem. Commun. 1977, 368-
370.
arachno-9-dppf-6-SB9H11 + BH3‚THF f
arachno-9-dppf(BH3)-6-SB9H11
+ THF (5)
4
In agreement with the structure proposed for 4, its 11B NMR
spectrum at 160.5 MHz shows the appropriate peaks for the
arachno-6-SB9H11 cage, as well as one additional peak at -38.9
(14) (a) Hertler, W. R.; Klanberg, F.; Muetterties, E. L. Inorg. Chem. 1967,
6, 1696-1706. (b) Siedle, A. R.; McDowell, D.; Todd, L. J. Inorg.
Chem. 1974, 13, 2735-2739. (c) Hilty, T. K.; Rudolph, R. W. Inorg.
Chem. 1979, 18, 1106-1109.
1
ppm for the BH3 group. The H NMR spectrum shows three
singlet resonances of intensities 2:4:2 attributed to the Cp

552 Inorganic Chemistry, Vol. 36, No. 4, 1997
Donaghy et al.
Figure 6. Proposed structure of [dppf-Me+][nido-9-MeS-7,8-C2B9H11-],
6.
at -17.6 ppm occurs in the dppf region, indicating one
uncoordinated phosphorus.
Attempts to prepare the dppf analog of the dicarbaborane
nido-9-Ph3P-7,8-C2B9H1115 by the reaction of nido-9-Me2S-7,8-
C2B9H11 with dppf in refluxing toluene (eq 7) did not yield the
expected ligand substitution product, 9-dppf-7,8-C2B9H11, but
gave instead the methylphosphonium salt of 9-MeS-7,8-
-
C2B9H11
.
nido-9-Me2S-7,8-C2B9H11 + dppf f
[dppf-Me+][9-MeS-7,8-C2B9H11
-
(7)
]
6
NMR spectra of the reaction mixture indicated that, even after
reflux for 4 days, the reaction did not go to completion.
Although the product could be separated by flash column
chromatography, it was necessary that it be stored at -78 °C
to prevent the re-formation of nido-9-Me2S-7,8-C2B9H11.
The 11B NMR spectrum of 6 at 160.5 MHz consists of eight
doublets and one singlet of equal intensities, similar to that of
nido-9-Me2S-7,8-C2B9H11, but with the singlet shifted upfield.
The singlet does not show phosphorus coupling, thus supporting
Figure 4. ORTEP plot of the structure of arachno-9-dppf-6-SB9H11,
3.
1
the retention of a sulfur-boron bond. The 13C and H NMR
spectra strongly support the structure shown in Figure 6, in
which one of the Me2S methyl groups has been transferred to
a dppf phosphorus, producing the phosphonium complex [dppf-
Figure 5. Proposed structure of nido-8-dppf-7-CB10H12, 5.
Me+][9-MeS-7,8-C2B9H11-], 6. Thus, both the H and 13C-
1
protons. The 13C NMR spectrum is similar to that found for 3.
The 31P NMR spectrum exhibits two broad resonances, one at
a shift (16.7 ppm) similar to that found for the borane-substituted
phosphorus in 1, while that assigned to the thiaborane-substituted
phosphine is observed at a shift (10.7 ppm) similar to that found
for 3.
{1H} NMR spectra show phenyl and cyclopentadienyl reso-
nances, indicating C1 symmetry, with one set of both the phenyl
and cyclopentadienyl carbons showing large JCP couplings that
1
are characteristic of organophosphoniums.12,16 The H NMR
spectrum also shows the two cage CH peaks and methyl
resonances arising from the MeS- (2.07 ppm) and MeP+ (2.64
2
ppm, JHP 13 Hz) groups. Likewise, in the 13C{1H} NMR
The reaction of the monocarbaborane nido-8-Me2S-7-CB10H12
with PPh3 has been shown to result in displacement of the Me2S
spectrum, the resonance assigned to the PMe+ carbon (9.78
ppm) shows coupling to phosphorus (JCP 60 Hz), while that of
the SMe is a singlet at 16.1 ppm. The 31P NMR spectrum is
also consistent, showing two resonances, with one in the normal
dppf region and the other at a chemical shift (23.41 ppm)
characteristic of a phosphonium.12
and formation of the phosphine adduct in good yields.3
A
similar reaction of nido-8-Me2S-7-CB10H12 with dppf (eq 6)
resulted in nido-8-dppf-7-CB10H12 in 35% yield.
nido-8-Me2S-7-CB10H12 + dppf f
The polyhedral cage systems discussed above were found to
form only monobase adducts; however, other polyhedral bo-
ranes, such as decaborane(14), B10H14, are capable of forming
dibase adducts. Thus, arachno-6,9-L2B10H12 complexes are
readily produced upon reaction of decaborane with 2 equiv of
many Lewis bases,17 including triphenylphosphine.17c The
reactions of decaborane(14) with bidentate organophosphine
bases, such as Ph2POPPh2, have also been found to produce
nido-8-dppf-7-CB10H
12 + Me2S (6)
5
Exact mass measurements and elemental analysis established
its composition. Supporting the structure proposed in Figure
5, the 11B NMR spectrum of 5 at 160.5 MHz has nine broad,
overlapping resonances in 1:1:2:1:1:1:1:1 ratios at chemical
shifts similar to those of nido-8-Ph3P-7-CB10H12.3 Likewise,
the 1H NMR spectrum contains two bridge hydrogen resonances,
a phenyl multiplet, and the cage CH resonance, at shifts
consistent with those found for nido-8-Me2S-7-CB10H12 and
nido-8-Ph3P-7-CB10H12.3 In agreement with the C1 symmetry
of the complex, the Cp region shows seven resonances, one of
intensity 2 and six of intensity 1. The 31P NMR spectrum is
similar to that of 3; the downfield peak at 3.9 ppm is once again
broad, indicating coordination to the boron, and the upfield peak
(15) Kim, K. M.; Do, J.; Knobler, C. B.; Hawthorne, M. F. Bull. Korean
Chem. Soc. 1989, 10, 321-323.
(16) Singh, G.; Reddy, G. S. J. Org. Chem. 1979, 44, 1057-1060.
(17) (a) Shore, S. G. In Boron Hydride Chemistry; Muetterties, E. L., Ed.;
Academic Press: New York, 1975; pp 79-174 and references therein.
(b) Hawthorne, M. F. In The Chemistry of Boron and its Compounds;
Muetterties, E. L., Ed.; Wiley: New York, 1967; Chapter 5, pp 223-
324 and references therein. (c) Hawthorne, M. F.; Pitochelli, A. R.
J. Am. Chem. Soc. 1958, 80, 6685.

Reactions of 1,1′-Bis(diphenylphosphino)ferrocene
Inorganic Chemistry, Vol. 36, No. 4, 1997 553
Figure 7. Possible structure of arachno-6,9-(dppf)2B10H12, 7.
polymeric materials of composition [Ph2POPPh2B10H12]n.18 The
corresponding reaction of decaborane with dppf produced both
arachno-6,9-(dppf)2B10H12, 7, and oligomeric materials of
formula [arachno-6,9-dppf-B10H12]n, 8, as shown in eq 8.
Figure 8. Possible structure of [arachno-6,9-dppf-B10H12]n, 8.
repeating unit containing one dppf and one decaborane fragment,
i.e. [dppf-B10H12]n. The 11B NMR spectrum of 8 consists of
three very broad unresolvable resonances, spanning the shift
ranges found for arachno-6,9-L2B10H12 compounds20 and the
[Ph2POPPh2B10H12]n polymer,18 suggesting the [arachno-6,9-
dppf-B10H12]n structure depicted in Figure 8. Its 1H NMR
spectrum contains a resonance at -3.78 ppm again consistent
with the bridging hydrogens on the B10H12 fragment, but the
remainder of the spectrum is complex with numerous broad
resonances for the phenyl and cyclopentadienyl protons. Like-
wise, the 31P NMR spectrum shows only broad peaks in the
region expected for coordinated phosphines. Preliminary SEC
molecular weight studies of this material show Mn of 1670 and
Mw of 2660, which would correspond to approximately three
dppf-decaborane units. This is perhaps surprising in light of
the much higher molecular weights attained by the [Ph2-
POPPh2B10H12]n polymers (27 000),18 but with more forcing
conditions and with solvents that prevent polymer precipitation,
it may be possible to substantially increase the degree of
polymerization.
arachno-6,9-(dppf) B H
B10H14 + dppf f
+
2
10 12
7
[arachno-6,9-dppf-B10H12]n
(8)
8
Oligomer 8 was isolated as a solid by its repeated precipitation
from pentane/methylene chloride solutions. Remaining in the
solution was 7 which was then chromatographically purified to
also give a solid. Both materials appear air and water stable.
The relative amounts of 7 and 8 varied with the reaction
conditions, with the formation of 7 favored by lower temper-
atures and shorter reaction times.
According to elemental analysis, 7 contains two dppf units
coordinated to a single B10H12 fragment. A possible structure
for this compound based on those previously observed for
arachno-6,9-L2B10H12 compounds19 is shown in Figure 7. The
11B NMR spectrum of 7 exhibits five resonances (four doublets
and one broad multiplet) of equal intensity. The broad
resonance at -37.2 ppm has a shift characteristic of the 6,9-
borons in arachno-6,9-L2B10H12 compounds20 and its multiplet
structure strongly suggests attachment of these borons to the
dppf phosphorus atoms. Normal 6,9-substituted decaborane
structures have C2V symmetry and thus exhibit only four
resonances in 2:4:2:2 ratios,20 instead of the five resonances
found for 7. It is possible, however, that, because of their large
size, the two 6,9-coordinated dppf units in 7 must be oriented
in such a fashion that the normal degeneracy of the B5, B7,
B8, and B10 atoms is broken into two sets, and indeed, the
doublets at -12.0 and -28.5 ppm fall on either side of the shift
of the single resonance normally expected for these borons. The
remaining two resonances at -6.0 and -51.5 ppm are near the
normal shifts expected for the 2,4- and 1,3-borons, respectively,
in arachno-6,9-L2B10H12 compounds.20 The 1H NMR spectrum
shows one broad resonance of intensity 2 at -2.5 ppm arising
from the bridging hydrogens expected at the B5-B10 and B4-
B7 edges of the decaborane fragment.19 The remainder of the
spectrum is similar to that of 3, showing sets of resonances
characteristic of inequivalent phenyl and cyclopentadienyl
groups, thus indicating the coordination of only one of the
phosphines in each of the dppf units. Consistent with this
conclusion, the 31P NMR spectrum shows two peaks with
chemical shifts and line widths characteristic of the coordinated
(15.2 ppm, broad) and uncoordinated (-17.7 ppm, sharp)
phosphines.
In summary, the results described above have demonstrated
that dppf can form strong molecular and polymeric adducts with
a variety of boranes, thiaboranes, and carboranes.21 Because
of the increased air and water stabilities of these adducts
compared to their unsubstituted boron starting materials, such
complexes may now find a variety of uses. One potential
application that takes advantage of the established bioactivity
of dppf1 is as boron-delivery agents in boron neutron capture
18
therapy (BNCT).22 In another area, the [Ph2POPPh2B10H12]n
and silylferrocene polymers23 were recently shown to serve as
precursors to BCP and SiCFe ceramic materials, suggesting that
boron-dppf polymers can have similar uses as precursors to
complex BCPFe ceramics. We are presently exploring such
properties, and these results will be reported in subsequent
publications.
Acknowledgment. We thank the National Science Founda-
tion for support of this work. We also thank Dr. Joe Barendt
at Callery Chemical Co. and Dr. Tom Baker of DuPont for gifts
of decaborane and Dr. E. E. Remsen at Monsanto for the GPC
results.
Supporting Information Available: Listings of atomic coordinates,
bond distances and angles, and thermal parameters for 1 and 3 and
figures showing NMR spectra (11B, 11B{1H}, 1H, and 13C) for compound
6 (14 pages). Ordering information is given on any current masthead
page.
IC9611913
The major product of the reaction in eq 8, was the solid
oligomeric material 8 which elemental analysis indicated had a
(21) For examples of the use of the dppf ligand in metallaborane chemistry
that does not involve boron-phosphorus interactions, see: Galsworthy,
J. R.; Housecraft, C. E.; Rheingold, A. L. J. Chem. Soc., Dalton Trans.
1996, 2917-2922 and references therein.
(22) Hawthorne, M. F. Angew. Chem., Int. Ed. Engl. 1993, 32, 950-984.
(23) (a) Manners, I. Angew. Chem., Int. Ed. Engl. 1996, 35, 1602-1621.
(b) Peterson, R.; Foucher, D. A.; Tang, B.-Z.; Lough, A.; Raju, N. P.;
Greedan, J. E.; Manners, I. Chem. Mater. 1995, 7, 2045-53. (c)
Peterson, R.; Foucher, D. A.; Tang, B.-Z.; Lough, A.; Raju, N. P.;
Greedan, J. E.; Manners, I. J. Chem. Soc., Chem. Commun. 1993, 523-
525.
(18) Seyferth, D.; Rees, W. S., Jr.; Haggerty, J. S.; Lightfoot, A. Chem.
Mater. 1989, 1, 45-52.
(19) (a) Reddy, J. V. D. M.; Lipscomb, W. N. J. Chem. Phys. 1959, 31,
610-616. (b) Reddy, J. V. D. M.; Lipscomb, W. N. J. Am. Chem.
Soc. 1959, 81, 754. (c) Sands, D. E.; Zalkin, A. Acta Crystallogr.
1962, 15, 410-417.
(20) Hyatt, D. E.; Scholer, F. R.; Todd, L. J. Inorg. Chem. 1967, 6, 630-
631.