Organophosphoryl adducts of tris(pentafluorophenyl)borane; crystal and molecular structure of B(C6F5)3·Ph3Po

Article abstract of DOI:10.1039/b100981h

The synthesis and characterisation of a series of phosphoryl donor complexes of B(C₆F₅)₃ were reported and their spectroscopic properties were investigated. The changes in the ³¹P NMR chemical shifts and the phosphoryl stretching frequencies arising from coordination of the phosphoryl ligand to B(C₆F₅)₃ were described. B(C₆F₅)₃ was further characterised in the solid state by a single-crystal X-ray diffraction study. The X-ray diffraction study displayed weak intramolecular π-stacking interactions between the eclipsed interlocking C₆F₅ and C₆H₅ rings.

Full text of DOI:10.1039/b100981h

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Organophosphoryl adducts of tris(pentafluorophenyl)borane;
crystal and molecular structure of B(C6F5)3ؒPh3PO
Michael A. Beckett,*a David S. Brassington,a Mark E. Lightb and Michael B. Hursthouseb
a Chemistry Department, University of Wales, Bangor, Gwynedd, UK LL57 2UW
b Chemistry Department, University of Southampton, Southampton, UK SO17 1BJ
Received 29th January 2001, Accepted 17th April 2001
First published as an Advance Article on the web 15th May 2001
A series of 1 : 1 adducts of B(C6F5)3 with the organophosphoryl ligands Et3PO, Ph3PO, Prn PO, Octn PO, (MeO)3PO,
3
3
(EtO)3PO, (PhO)3PO, (EtO)2(H)PO, (BunO)2(H)PO, (PhO)2(H)PO, (MeO)2MePO, (EtO)2MePO, (EtO)2PhPO, and
(EtO)Me2PO have been synthesized and characterised by elemental analysis, mp, and spectroscopic (1H, 13C, 11B, 19F,
31P NMR and IR) methods. B(C6F5)3ؒPh3PO was further characterised in the solid state by a single-crystal X-ray
diffraction study. 31P NMR chemical shifts and ν(PO) IR stretching frequencies are discussed in relation to
substituent at phosphorus.
Table 1 Selected spectroscopic data for phosphoryl adducts of
B(C6F5)3
Introduction
The triorganoborane B(C6F5)3 has attracted considerable atten-
tion recently due to its high thermal and aqueous stability1,2
Compound
and its ability to function as a stoichiometric or catalytic Lewis
Adduct no.
Ligand
∆δ (31P)a
∆ν(PO)b/cmϪ1
acid in many useful organic transformations.3–7 The B(C6F5)3ؒL
Lewis acid/base adducts are well known with examples reported
for L = NH3 and amines,1,2 nitriles and isocyanides,8 H2O,9,10
O-carbonyl donors,11 PH3,12 and organophosphines.1,2,8,13 We
have recently reported14 in a preliminary communication the
synthesis of the first phosphoryl adduct B(C6F5)3ؒEt3PO 1 and
used Gutmann’s method15,16 to determine the relative Lewis
acidity of B(C6F5)3. This report describes the synthesis and
characterisation of a series of phosphoryl donor complexes of
B(C6F5)3, and an investigation into their spectroscopic proper-
ties. In particular, changes in the 31P NMR chemical shifts and
the phosphoryl stretching frequencies arising from co-
ordination of the phosphoryl ligand to B(C6F5)3 are described.
We also report a single-crystal X-ray structural determination
of B(C6F5)3ؒPh3PO 2 which displays weak intramolecular
π-stacking interactions between the eclipsed interlocking C6F5
and C6H5 rings.
1
2
Et3PO
Ph3PO
25.9
Ϫ4.2
21.6
22.5
Ϫ3.9
Ϫ8.2
Ϫ9.2
Ϫ3.0
Ϫ1.7
Ϫ1.0
Ϫ2.2
0.2
Ϫ21c
Ϫ13
Ϫ26
Ϫ8d
Ϫ56
Ϫ67
Ϫ41
Ϫ78
Ϫ73
Ϫ30
Ϫ52
Ϫ55
Ϫ76
Ϫ23
3
Prn PO
3
4
Octn PO
3
5
(MeO)3PO
(EtO)3PO
(PhO)3PO
(EtO)2(H)PO
(BuO)2(H)PO
(PhO)2(H)PO
(MeO)2MePO
(EtO)2MePO
(EtO)2PhPO
(EtO)Me2PO
6
7
8
9
10
11
12
13
14
5.8
3.8
a In CDCl3. ∆δ = δ(adduct) Ϫ δ(free
ν(PO)(free base)
.
b KBr disk. ∆ν = ν(PO)(adduct) Ϫ
.
c Value for free basebtasaek) en from ref. 29. d Thin film.
section. The formulation of these products as adducts follows
from their 11B NMR chemical shifts (δ Ϫ0.2 to Ϫ9.3), in the
region normally observed for four-co-ordinate tetrahedral
boron centres17 and upfield of the signal for free B(C6F5)3
(δ ϩ599), and by confirmatory single-crystal X-ray crystallo-
graphic structures of 114 and 2. The room temperature (20 ЊC)
1H, 13C, 11B, 19F and 31P NMR spectra that we were able to
measure were consistent with the proposed structures. 19F
spectra were obtained for 1–10 and these showed the expected
three resonances, of relative intensity 2 : 2 : 1, for ortho, meta,
and para aryl substituents at δ ca. Ϫ164, Ϫ135, and Ϫ157,
respectively.8 The 13C spectra of adducts showed, in addition to
resonances associated with the phosphoryl ligand,18 doublets
{1J(CF) ca. 240 Hz} for the ortho, meta and para resonances
of the perfluoroaryl groups of B(C6F5)3 at δ ca. 148, 137, 140,
respectively.8,18,19 We were unable to observe the ipso carbons.
31P NMR data are described in detail below. IR spectra all
showed characteristic vibrations associated with B(C6F5)3,
including a strong band at ca. 1100 cmϪ1, and a strong ν(PO) at
1130–1260 cmϪ1. The ν(PO) vibration is also discussed in detail
below.
Results and discussion
The reaction of one equivalent of the phosphoryl compound
(L) with one equivalent of B(C6F5)3 in pentane solution rapidly
afforded the analytically pure adducts, B(C6F5)3ؒL 1–14, in
moderate to high yields. The phosphoryl compounds used as
Lewis bases in this study were the triorganophosphine oxides
{Et3PO, Ph3PO, Prn PO, and Octn PO}, and the organoesters
3
3
of phosphoric acid {(MeO)3PO, (EtO)3PO, and (PhO)3PO},
phosphonic and organophosphonic acids {(EtO)2(H)PO,
(BunO)2(H)PO, (PhO)2(H)PO, (MeO)2MePO, (EtO)2MePO,
and (EtO)2PhPO}, and a diorganophosphinic acid {(EtO)-
Me2PO}; compound numbers are given in Table 1. All adducts,
except 4, which was a viscous liquid, were air-stable colourless
solids. They were all readily soluble in chlorinated solvents and
diethyl ether, but insoluble in toluene and light petroleum. The
adducts of the diesters of the phosphonic acids (8–10) were
very deliquescent.
The adducts 1–14 were all characterised by satisfactory elem-
ental analysis data, mp, and IR and NMR (1H, 13C, 11B, 19F, 31P)
spectroscopy and full data are given in the Experimental
1768
J. Chem. Soc., Dalton Trans., 2001, 1768–1772
This journal is © The Royal Society of Chemistry 2001
DOI: 10.1039/b100981h

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Table 2 Selected bond lengths (Å) and angles (Њ) for 2
P1–O1
P1–C1
P1–C13
B1–C25
1.497(2)
1.791(2)
1.783(2)
1.639(3)
B1–O1
P1–C7
B1–C19
B1–C31
1.538(3)
1.791(2)
1.632(3)
1.643(3)
P1–O1–B1
O1–P1–C7
C1–P1–C7
C7–P1–C13
O1–B1–C25
C19–B1–C25
C25–B1–C31
178.7(2)
109.6(1)
110.2(1)
108.7(1)
105.1(2)
113.7(2)
114.2(2)
O1–P1–C1
109.6(1)
O1–P1–C13
C1–P1–C13
O1–B1–C19
O1–B1–C31
C19–B1–C31
109.9(1)
108.9(1)
104.9(2)
105.1(2)
112.7(2)
between two of its C6F5 rings.10 Selected bond length and bond
angle parameters for 2 are given in Table 2. Other crystal-
lographically characterised adducts of B(C6F5)3 to have been
reported include L = PPh3,8 RCN {R = Me, 4-MeC6H4 or
t
4-NO2C6H4},8 RNC {R = tBu or CMe2CH2 Bu},8 H2O,9
PhC(X)O {X = H or Me},11 PH3,12 and PButH2.13 The B and P
atoms in 2 are both 4-co-ordinate with angles subtended at
these atoms close to those expected for σ-framework sp3 hybrid-
isation [104.9(2)–114.2(2), av. 109.3Њ, and 108.7(1)–110.2(1), av.
109.5Њ, for B and P respectively]. The detailed deviation of
angles at B indicates back strain in the acid upon adduct form-
ation with larger C–B1–C angles [112.7(2)–114.2(2), av.113.5Њ]
and smaller O1–B1–C angles [104.9(2)–105.1(2), av. 105.0Њ].
The deviation from idealised tetrahedral angles at B is less
marked than has been observed previously in other
adducts.8,11,13,14 The B1–O1 bond length at 1.538(3) Å is similar
to that found for 1 [1.533(3) Å]14 and BF3ؒPh3PO [1.516(3)
Å)],20 shorter than that in BF3ؒPhC(H)O [1.591(6) Å]21 and
B(C6F5)3ؒH2O [1.597(2) Å],9 and at the lower end of the range
observed [1.52(1)–1.610(8) Å] for B(C6F5)3ؒPhC(X)O com-
plexes.11 Shorter B–O distances have been reported in metal–
oxo adducts of B(C6F5)3, e.g. [WO{OB(C6F5)3}3]2Ϫ [1.491(3)–
1.508(3) Å]22 and [Zr(Cp*)2{OB(C6F5)3}] [1.460(6) Å].23 As
noted above, the two-co-ordinate O atom bridges the P and B
atoms with a P1–O1–B1 angle of 178.7(2)Њ. P–O–M angles in
Ph3PO complexes are variable and range from 123.0(4) (in
SeOCl2ؒPh3PO24) to 180Њ (in AlCl3ؒPh3PO18) and a possible
explanation for this has been offered in terms of the relative
π-acceptor properties of the acid.25 However, in view of the
large difference in this angle for 1 and 2 it is clear that other
factors also need to be considered. The angle at O when bound
to main group atoms (X) from the 2nd short period is renowned
for its flexibility and intermolecular crystal packing forces are
sufficient to cause a remarkable difference in B–O–X angles.26
The intramolecular π-stacking interactions noted above for 2
are maximised with a linear B–O–P linkage and we suggest that
this must be a dominant factor in the energetics of this system.
The P–O bond length at 1.497(2) Å is, within error as found for
1,14 similar to that found for BF3ؒPh3PO [1.523(3) Å)],20 and
slightly longer than that found for Ph3PO (1.483(2) Å)27 indicat-
ing a slight reduction of bond order upon adduct formation.
Phosphorus-31 NMR data for all the adducts are given in the
Experimental section and ∆δ values (δadduct Ϫ δfree base), which
ranged from from Ϫ9.2 to 25.9, are given in Table 1. Rather
than reflecting change of electron density at P, these shifts are a
consequence of the Lewis acid perturbing the 31P chemical shift
tensors, which have a component along the PO axis of the
phosphoryl ligand.28 Owing to variations in molecular sym-
metry, these 31P chemical shift tensors will differ for each class
of phosphoryl derivative, with the effect that ∆δ values are
unlikely to be uniform. The P atoms in the phosphoryl com-
pounds with alkyl substituents were deshielded upon co-
ordination to B(C6F5)3, whilst in phosphoryl compounds with
alkoxy or aryloxy groups the P atoms were slightly shielded
upon co-ordination. This substituent effect appears additive
with ∆δ values broadly following the order phosphates
Fig. 1 Molecular structure of B(C6F5)3ؒPh3PO 2 showing the atomic
numbering scheme.
Fig. 2 (a) A view down the P1–O1 bond of 2 showing the eclipsed
conformation of the adduct and the π interactions between the phenyl
groups of the phosphine oxide and the C6F5 groups of the borane. (b) A
view of 2 showing the aryl π interactions between a C6F5 and a C6H5
unit.
The adduct 2 was further characterised in the solid state by a
single-crystal X-ray diffraction study. Crystals of 2, were grown
from layered CHCl3–hexane solution, and a drawing of its
molecular structure is given in Fig. 1. The molecular structure is
essentially as might be expected for the component parts with
the acid B(C6F5)3 and the base Ph3PO joined together via a
O→B co-ordinate bond. The overall structure of 2 is grossly
similar to that of 114 but for the angle at O in the B–O–P
linkage being almost linear [178.7(2)Њ] in 2 rather than bent
[161.0(2)Њ] as was found for 1. These two structures are the only
crystallographically characterised structures of phosphoryl
adducts of B(C6F5)3. The B–C bonds of the borane are almost
eclipsed with respect to the P–C bonds of the phosphine oxide,
Fig. 2(a). There are weak intramolecular π-stacking inter-
actions between the three Ph groups of the phosphine oxide
and the three C6F5 groups of the borane, Fig. 2(b). A similar,
but stronger, π-stacking interaction has been noted in
B(C6F5)3ؒPhC(X)O (X = OEt or NPri2)11 where the bent B–O–C
system enables a closer π interaction between the Ph ring of the
base and a C6F5 ring of the acid. The hydroxy bridged borate
anion [(C6F5)3BO(H)B(C6F5)3]Ϫ, with a staggered conformation
and a B–O–B angle of 139.6(5)Њ, has a strong π interaction
J. Chem. Soc., Dalton Trans., 2001, 1768–1772
1769

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(≈Ϫ5) < alkylphosphonates(≈Ϫ1) < dialkylphosphinates(≈ϩ4)
< trialkylphosphine oxides (≈ϩ24). Burford and co-workers18,20
observed deshielding of the phosphorus centre in adducts of
Ph3PO with BF3, BCl3, AlCl3, AlBr3 and GaCl3, and slight
shielding at phosphorus in (PhO)3POؒAlCl3. The ∆δ values
obtained for the B(C6F5)3 adducts of phosphonic acid esters
(≈Ϫ2) were similar to those for alkylphosphonate esters indicat-
ing that the effect of H was comparable to that of an alkyl
group. The phosphoryl derivatives that showed the largest
∆δ(31P) values were the trialkylphosphine oxides, with the
∆δ value for Et3PO being marginally greater than those of
Prn PO and Octn PO.
operating at 250, 62.8, 80.2 and 101.25 MHz respectively and
19F NMR spectra on a Bruker 350 at 338.0 MHz. Chemical
shifts are given in ppm with positive values towards high fre-
quency (downfield) of SiMe4 (1H, 13C), BF3ؒOEt2 (11B), CFCl3
(19F), and 85% H3PO4 (31P). Elemental analysis (C,H,N) were
obtained on a Carlo-Erba MOD-1106 instrument using helium
as a carrier gas. The phosphoryl free bases, with the exception
of Me2(EtO)PO which was prepared by a standard method,33
were obtained commercially and used as supplied. B(C6F5)3 and
B(C6F5)3ؒEt3PO 1 were prepared by literature methods.14,34
(b) Synthesis
3
3
Symons and Eaton29 have noted that the phosphoryl stretch
of Et3PO was solvent dependent and have correlated ∆ν(PO)
with Gutmann’s15,16 acceptor number (AN) solvent scale. We
were interested to see if there were any noteworthy changes
associated with ∆ν(PO) for the phosphoryl adducts 1–14 of
the relatively strong Lewis acid, B(C6F5)3. Related to this,
Lappert30,31 used ∆ν(CO) of ethyl acetate upon adduct form-
ation as a measure of Lewis acidity, and we have recently pre-
pared B(C6F5)3ؒMeC(OEt)O and examined its IR spectrum.14
The ν(PO) stretching data for adducts 1–14 are given in
the Experimental section and ∆ν(PO) values are reported in
Table 1; the negative ∆ν(PO) values indicate that ν(PO) is
shifted to lower wavenumber upon co-ordination to B(C6F5)3.
The ∆ν(PO) values ranged from Ϫ8 to Ϫ78 cmϪ1. Detailed
examination of the data revealed that the magnitude of ∆ν(PO)
was lowest for triorganophosphine oxides and greatest for
species with OR or OAr groups at P. The ∆ν(PO) ranges associ-
ated with the various classes of compounds, arranged in
decreasing order of P–C bonds, were Ϫ8 to Ϫ26 (phosphine
oxides), Ϫ23 (phosphinate esters), Ϫ52 to Ϫ78 (phosphonate
esters), and Ϫ41 to Ϫ67 (phosphate esters). The adducts of
phosphonate esters had similar ∆ν(PO) ranges irrespective of
whether H or alkyl was bound to P, although a smaller shift was
observed for 10. A theoretical study8 has demonstrated that
B(C6F5)3 is a hard acid and that its bonding to Lewis bases is
dominated by electrostatic effects. The phosphoryl bond may be
drawn as a resonance hybrid of two limiting canonical forms
The adducts 2–14 were all prepared in an analogous manner to
1 as described in ref. 14. Selected spectroscopic data are given in
Table 1 and full characterisation data are given below. Crystals
of 2 suitable for a single-crystal X-ray diffraction analysis were
grown by diffusion of a hexane into a CHCl3 solution of 2.
B(C6F5)3ؒPh3PO 2. Yield 37%. mp 278–280 ЊC. Calc. for
C36
H15BF15OP: C, 54.7; H, 1.9. Found: C, 54.7; H, 1.8%. NMR
1
(CDCl3/RT): H (δ), 7.6 (m); 13C-{1H} (δ), 128.8 (d) J(CP) 2.8,
129.0 (d) J(CP) 2.7, 131.8 (d) J(CP) 10.5, 136.7 (d) 1J(CF) 237,
139.2 (d) J(CF) 254, 147.8 (d) J(CF) 241 Hz; 11B-{1H} (δ),
Ϫ9.2; 19F (δ), Ϫ134.9 , Ϫ158.7, Ϫ164.9; 31P-{1H} (δ), ϩ24.3. IR
(KBr disk/cm
1
1
Ϫ1): 3010, 1684, 1646, 1517, 1464, 1376, 1285,
1177 (P᎐O), 1126, 1102, 978, 848, 793, 773, 750, 684, 616, 575,
᎐
532.
B(C6F5)3ؒPrn PO 3. Yield 54%. mp 140–141 ЊC. Calc. for
3
C27H21BF15OP: C, 47.1; H, 3.0. Found: C, 47.1; H 2.8%. NMR
(CDCl3/RT): 1H (δ), 1.0 (dt, 3H) 3J(HH) 7.0, 4J(PH) 1.5, 1.5 (m,
3
2H), 1.83 (m, 2H); 13C-{1H} (δ), 14.9 (d) J(PC) 4, 15.5 (d)
2J(PC) 17.0, 27.1 (d) 1J(PC) 65.0, 137 (d) 1J(CF) 252, 140.0 (d)
1
1J(CF) 255, 147.7 (d) J(CF) 238 Hz; 11B-{1H} (δ), Ϫ2.6; 19F
(δ), Ϫ134.5, Ϫ158.4, Ϫ164.6; 31P-{1H} (δ), ϩ69.3. IR (KBr
disk/cmϪ1): 3000, 1519, 1461, 1373, 1284, 1132 (P᎐O), 1102,
᎐
979, 861, 797, 767, 738, 679, 615, 579.
B(C6F5)3ؒOctn3PO 4. Yield 51%. Oily liquid. Calc. for
C42H51BF15OP: C, 56.1; H, 5.7. Found: C, 56.1; H 5.5%. NMR
(CDCl3/RT): 1H (δ), 0.9 (t, 3H) 3J(HH) 6.4, 1.25 (m, 12H), 1.85
(m, 2H); 13C-{1H} (δ), 13.9, 21.05 (d) J(CP) 3.8, 22.5, 25.3 (d)
Ϫ
ϩ
R3Pϩ–OϪ and R P ᎐O , with the former having a heavier
᎐
᎐
3
weighting. An electrostatic interaction with B(C6F5)3 would fur-
ther favour the former and effectively reduce the PO bond
order, and hence ν(PO). The absolute value of ν(PO) for phos-
phoryl derivatives may accurately be calculated32 using an
empirical relationship involving additive electronegativities
(inductive effects) of substituents at P. The ∆ν(PO) values upon
adduct formation are greatest where π resonance from a
substituent is possible indicating that structures such as
(PhO) (PhOϩ᎐)P–OϪ may be important in lowering the PO
2
1J(CP) 65.8, 28.7, 28.8, 30.57, 30.7 (d) J(PC) 15.7, 31.6, 137.1
(d) 1J(CF) 238, 139.6 (d) 1J(CF) 258, 147.8 (d) 1J(CF) 240 Hz;
11B-{1H} (δ), Ϫ3.8; 19F (δ), Ϫ134.5, Ϫ158.7, Ϫ164.6; 31P-{1H}
(δ), ϩ70.6. IR (thin film/cmϪ1): 2929, 1644, 1517, 1467, 1376,
1284, 1143 (P᎐O), 1100, 981, 912, 742, 650.
᎐
᎐
2
B(C6F5)3ؒ(MeO)3PO 5. Yield 48%. mp 210–212 ЊC. Calc. for
C21H9BF15O4P: C, 38.7; H, 1.4. Found: C, 38.7; H 1.4%. NMR
(CDCl3/RT): 1H (δ) 3.68 (d) 3J(PH) 10.7 Hz; 13C-{1H} (δ), 56.0
bond order upon adduct formation.
2
1
1
Conclusion
(d) J(CP) 132, 136.9 (d) J(CF) 254, 139.8 (d) J(CF) 245,
1
147.8 (d) J(CF) 241 Hz; 11B-{1H} (δ), Ϫ1.7; 19F (δ), Ϫ135.1,
A linear co-ordination mode for the phosphoryl group has been
observed in the solid state of the adduct B(C6F5)ؒPh3PO and
this has been attributed to intramolecular π-stacking inter-
action between aryl rings, rather than electronic effects or
destabilising steric interactions associated with the acceptor or
the phosphoryl group. Variations in ∆δ(31P) and ∆ν(PO) data
for the series of phosphoryl adducts of B(C6F5)3 have been
accounted for in terms of substituent effects at phosphorus.
Ϫ157.8, Ϫ164.6; 31P-{1H} (δ), Ϫ2.55. IR (KBr disk/cmϪ1):
2995, 1648, 1510, 1470, 1378, 1284, 1226 (P᎐O), 1104, 1075,
᎐
984, 865, 775, 738, 678, 618, 576, 512.
B(C6F5)3ؒ(EtO)3PO 6. Yield 47%. mp 150–151 ЊC. Calc. for
C24H15BF15O4P: C, 41.5; H, 2.2. Found: C, 41.3; H 2.1%. NMR
1
3
(CDCl3/RT): H (δ), 1.3 (t, 3H) J(HH) 7.3, 3.9 (quint, 2H)
3J(HH) 7.3, J(PH) 7.3; 13C-{1H} (δ), 15.8 (d) J(PC) 6.7, 63.7
(d) 2J(PC) 5.7, 136.5 (d) 1J(CF) 240, 139.3 (d) 1J(CF) 269, 148.1
(d) 1J(CF) 231 Hz; 11B-{1H} (δ), Ϫ3.7; 19F (δ), Ϫ135.6, Ϫ157.7,
Ϫ164.9; 31P-{1H} (δ), Ϫ10.1. IR (KBr disk/cmϪ1): 2995, 1647,
3
3
Experimental
(a) General
1521, 1472, 1378, 1287, 1208 (P᎐O), 1106, 1049, 981, 774, 739,
᎐
677, 617.
Reactions were carried out under N2 in dried solvents. IR
spectra were recorded on a Perkin-Elmer FT-IR spectrometer
as KBr discs or as thin films between NaCl plates, 1H, 13C, 11
B
B(C6F5)3ؒ(PhO)3PO 7. Yield 35%. mp 185–186 ЊC. Calc. for
C36H15BF15O4P: C, 51.6; H, 1.8. Found: C, 51.3; H 1.5%. NMR
and 31P NMR on a Bruker AC250 CP/MAS NMR spectrometer
1770 J. Chem. Soc., Dalton Trans., 2001, 1768–1772

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(CDCl3/RT): 1H (δ), 7.3 (m); 13C-{1H} (δ), 119.8 (d) 3J(CP) 4.7
2J(PH) 14.0, 4.1 (m, 2H); 13C-{1H} (δ), 13.4 (d) 1J(CP) 99, 15.6
1
ortho, 126.1 para, 129.9 meta, 136.7 (d) J(CF) 244, 141.4 (d)
(d) 3J(PC) 7.6, 64.4 (d) 2J(CP) 7.6, 137.1 (d) 1J(CF) 254, 139.7
1 1
1J(CF) 251, 147.9 (d) 1J(CF) 255 Hz; 11B-{1H} (δ), Ϫ1.2; 19F (δ),
Ϫ135.4, Ϫ157.1, Ϫ164.1; 31P-{1H} (δ), Ϫ27.5. IR (KBr disk/
(d) J(CF) 251, 147.8 (d) J(CF) 236 Hz; 11B-{1H} (δ), Ϫ9.3;
31P-{1H} (δ), ϩ54.5. IR (KBr disk/cmϪ1): 3002, 1648, 1559,
cmϪ1): 3050, 1646, 1590, 1525, 1464, 1376, 1287, 1255 (P᎐O),
1521, 1458, 1399, 1375, 1319, 1284, 1187 (P᎐O), 1102, 1042,
᎐
᎐
1158, 1106, 1040, 982, 911, 764, 736, 686, 675, 616.
971, 890, 853, 797, 772, 743, 682, 617.
B(C6F5)3ؒ(EtO)2(H)PO 8. Yield 48%. mp 120–122 ЊC. Calc.
(c) Crystal structure of 2
for C22H11BF15O3P: C, 40.7; H, 1.7. Found: C, 40.5; H 1.7%.
Cell dimensions and intensity data for 2 were recorded at 150 K,
using a Nonius KappaCCD area detector diffractometer
mounted at the window of a molybdenum rotating anode (50
kV, 90 mA, λ = 0.71073 Å). The crystal-to-detector distance
was 30 mm and ꢀ and Ω scans (2Њ increments, 10 s exposure
time) were carried out to fill the Ewald sphere. Data collection
and processing were carried out using the programs COL-
LECT,35 DENZO36 and maXus37 and an empirical absorption
correction was applied using SORTAV.38,39 The structure was
solved via direct methods40 and refined by full matrix least
squares40 on F2. Non-hydrogen atoms were refined anisotropic-
ally. Hydrogen atoms were located from the difference map and
fully refined. Crystal data: C36H15BF15OP, Mr = 790.26, T =
150(2) K, monoclinic, space group C2/c, a = 31.0247(4),
b = 9.4124(2), c = 22.5961(3) Å, β = 105.9570(13)Њ, V =
6344.19(18) Å3, µ = 0.207 mmϪ1, Z = 8, reflections collected
31694, independent reflections 5572 (Rint = 0.069), final R
indices [I > 2σI] R1 = 0.0395, wR2 = 0.0934, R (all data)
R1 = 0.0620, wR2 = 0.1031.
1
NMR (CDCl3/RT): H (δ), 1.33 (6H), 4.04 (4H), 6.5 (d, 1H)
3
2
1J(PH) 700; 13C-{1H} (δ), 15.8 (d) J(CP) 6.7, 63.6 (d) J(PC)
6.8, 137.0 (d) 1J(CF) 253, 140.9 (d) 1J(CF) 264, 147.9 (d)
1J(CF) 247 Hz; 11B-{1H} (δ), Ϫ2.1; 19F (δ), Ϫ135.5, Ϫ157.5,
Ϫ164.3; 31P-{1H} (δ), ϩ3.4 1J(PH) 700 Hz. IR (KBr disk/cmϪ1):
2997, 1647, 1521, 1472, 1380, 1288, 1180 (P᎐O), 1107, 1043,
᎐
970, 772, 682, 551.
B(C6F5)3ؒ(BunO)2(H)PO 9. Yield 37%. mp 44–46 ЊC. Calc. for
C24H15BF15O3P: C, 44.2; H, 2.7. Found: C, 43.9; H 2.7%. NMR
(CDCl3/RT): 1H (δ), 0.9 (q, 6H) 3J(HH) 6.7, 1.3 (m, 4H), 1.6 (m,
1
4H), 4.1 (m, 4H), 6.9 (d, 1H) J(PH) 750; 13C-{1H} (δ), 15.3,
1
15.4, 15.5, 15.6, 64.8, 64.9, 67.5, 67.6, 137.0 (d) J(CF) 245,
1
1
140.0 (d) J(CF) 245, 147.8 (d) J(CF) 239 Hz; 11B-{1H} (δ),
Ϫ2.2; 19F (δ), Ϫ135.4, Ϫ157.3, Ϫ164.3; 31P-{1H} (δ), ϩ5.2
1J(PH) 750 Hz. IR (KBr disk/cmϪ1): 3000, 1692, 1646, 1598,
1518, 1469, 1379, 1289, 1188 (P᎐O), 1104, 976, 907, 734, 650.
᎐
B(C6F5)3ؒ(PhO)2(H)PO 10. Yield 55%. mp 130–132 ЊC. Calc.
CCDC reference number 155795.
See http://www.rsc.org/suppdata/dt/b1/b100981h/ for crystal-
lographic data in CIF or other electronic format.
for C30H11BF15O3P: C, 48.2; H, 1.5. Found: C, 47.9; H 1.4%.
1
1
NMR (CDCl3/RT): H (δ), 7.2 (d, 1H) J(PH) 740, 7.2 (m,
10H); 13C-{1H} (δ), 120.1 (d) J(PC) 4.8 Hz, 126.4, 130.2, 137.1 (d)
1J(CF) 238, 139.9 (d) 1J(CF) 149, 147.8 (d) 1J(CF) 238;
11B-{1H} (δ), Ϫ0.2; 19F (δ), Ϫ135.5, Ϫ156.7, Ϫ163.7; 31P-{1H}
(δ), Ϫ1.2 1J(PH) 739 Hz. IR (KBr disk/cmϪ1): 3000, 1649, 1596,
Acknowledgements
We acknowledge EPSRC support with a project studentship
and use of X-ray crystallographic facilities at Southampton
University, and Kings College, London for 19F NMR spectra.
We also acknowledge helpful and constructive comments from
a referee.
1519, 1472, 1373, 1290, 1250 (P᎐O), 1190, 1102, 1025, 961, 861,
᎐
761, 685.
B(C6F5)3ؒ(MeO)2MePO 11. Yield 42%. mp 226–228 ЊC. Calc.
for C21H9BF15O3P: C, 39.7; H, 1.4. Found: C, 39.4; H 1.4%.
1
2
3
NMR (CDCl3/RT): H (δ), 1.3 (d) J(PH) 17.7; 3.6 (d) J(PH)
11.6 Hz; 13C-{1H} (δ), 8.7 (d) J(CP) 146, 52.9 (d) J(CP) 6.7,
136.9 (d) J(CF) 258, 139.2 (d) J(CF) 259, 147.9 (d) J(CF)
240.0 Hz; 11B-{1H} (δ), Ϫ1.2; 19F (δ), Ϫ135.5, Ϫ157.2, Ϫ164.1;
31P-{1H} (δ), ϩ29.9. IR (KBr disk/cmϪ1): 2997, 1642, 1554,
1
2
References
1
1
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2J(HP) 18, 4.1 (m, 4H); 13C-{1H} (δ), 9.8 (d) J(CP) 162, 15.6
(d) 2J(CP) 6.7, 65.7 (d) 3J(CP) 6.8, 137.2 (d) 1J(CF) 246.0, 139.7
(d) 1J(CF) 244, 147.7 (d) 1J(CF) 245.0 Hz; 11B-{1H} (δ), Ϫ2.5;
31P-{1H} (δ), ϩ27.8. IR (KBr disk/cmϪ1): 3002, 1647, 1518,
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᎐
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B(C6F5)3ؒ(EtO)2PhPO 13. Yield 49%. mp 170–172 ЊC. Calc.
for C28H15BF15O3P: C, 47.4; H, 2.1. Found: C, 47.3; H 1.8%.
NMR (CDCl3/RT): 1H (δ), 1.2 (t, 6H) 3J(HH) 6.5, 3.91 (t, 4H)
3J(HH) 7.3, 7.44 (m, 5H); 13C-{1H} (δ), 15.9, 63.5, 128.9 (d)
J(CP) 12.5, 131.2 (d) J(CP) 10.1, 133.6 (d) J(CP) 4.8, 137.0 (d)
1J(CF) 252.0, 139.9 (d) 1J(CF) 258, 147.4 (d) 1J(CF) 273.0 Hz;
11B-{1H} (δ), Ϫ1.6; 31P-{1H} (δ), ϩ16.55. IR (KBr disk/cmϪ1):
3001, 2995, 1734, 1684, 1654, 1560, 1522, 1456, 1291, 1174
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(P᎐O), 1096, 1027, 976, 804, 749, 694, 560, 534.
᎐
B(C6F5)3ؒ(EtO)Me2PO 14. Yield 42%. mp 168–170 ЊC. Calc.
for C22H11BF15O2P: C, 41.7; H, 1.8. Found: C, 41.6; H 1.7%.
NMR (CDCl3/RT): 1H (δ), 1.27 (q, 3H) 3J(HH) 7.0, 1.70 (d, 6H)
J. Chem. Soc., Dalton Trans., 2001, 1768–1772
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