Tin(IV) fluoride complexes with tertiary phosphane ligands - A comparison of hard and soft donor ligands

Article abstract of DOI:10.1002/ejic.200600202

The first phosphane complexes of the hard Lewis acid SnF₄ have been synthesised including trans-[SnF₄(PR₃)₂] (R = Me or Cy) and cis-[SnF₄(diphosphane)] [diphosphane = R ₂P(CH₂)₂-PR₂, R = Me, Et, Ph or Cy; o-C₆H₄(PR₂)₂, R = Me or Ph] and characterised by IR and multinuclear NMR (¹H, ¹⁹F, ³¹P, ¹¹⁹Sn) spectroscopy. The crystal structures of trans-[SnF₄(PCy₃)₂] and cis-[SnF ₄{Et₂P(CH₂)₂PEt₂}] are reported. Tin(IV) fluoride complexes of 2,2′-bipyridyl, 1,10-phenanthroline, MeO(CH₂)₂OMe, Me₂N(CH ₂)₂NMe₂, pyridine and THF have been characterised by multinuclear NMR spectroscopy, the structures of cis-[SnF ₄(L-L)] (L-L = 1,10-phenanthroline and MeO(CH₂) ₂OMe) determined, and the properties were compared with those of the phosphane complexes. Complexes of o-C₆H₄(PMe ₂)₂, Et₂P(CH₂)₂PEt ₂, and MeC(CH₂AsMe₂)₃ with SnCl ₄ and SnBr₄ are also reported and the structures of cis-[SnCl₄{Et₂P(CH₂)₂PEt ₂}] and cis-[SnBr₄{κ²-MeC(CH ₂AsMe₂)₃}] described. Attempts to prepare tertiary arsane complexes of SnF₄ have been unsuccessful. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.

Full text of DOI:10.1002/ejic.200600202

FULL PAPER
DOI: 10.1002/ejic.200600202
Tin(IV) Fluoride Complexes with Tertiary Phosphane Ligands – A Comparison
of Hard and Soft Donor Ligands
Martin F. Davis,[a] Maria Clarke,[a] William Levason,*[a] Gillian Reid,[a] and
Michael Webster[a]
Keywords: Tin / Fluoride / Phosphane / Multinuclear NMR / Crystal structures
The first phosphane complexes of the hard Lewis acid SnF4
have been synthesised including trans-[SnF4(PR3)2] (R = Me
anthroline and MeO(CH2)2OMe) determined, and the prop-
erties were compared with those of the phosphane com-
or Cy) and cis-[SnF4(diphosphane)] [diphosphane = R2P(CH2)2- plexes. Complexes of o-C6H4(PMe2)2, Et2P(CH2)2PEt2, and
PR2, R = Me, Et, Ph or Cy; o-C6H4(PR2)2, R = Me or Ph] and
characterised by IR and multinuclear NMR (1H, 19F, 31P,
119Sn) spectroscopy. The crystal structures of trans-
[SnF4(PCy3)2] and cis-[SnF4{Et2P(CH2)2PEt2}] are reported.
Tin(IV) fluoride complexes of 2,2Ј-bipyridyl, 1,10-phenan-
throline, MeO(CH2)2OMe, Me2N(CH2)2NMe2, pyridine and
THF have been characterised by multinuclear NMR spec-
troscopy, the structures of cis-[SnF4(L–L)] (L–L = 1,10-phen-
MeC(CH2AsMe2)3 with SnCl4 and SnBr4 are also reported
and the structures of cis-[SnCl4{Et2P(CH2)2PEt2}] and cis-
[SnBr4{κ2-MeC(CH2AsMe2)3}] described. Attempts to pre-
pare tertiary arsane complexes of SnF4 have been unsuccess-
ful.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2006)
lysed, is otherwise rather unreactive and insoluble in weak
donor solvents. Tudela and co-workers have reported[18] the
preparation of [SnF4(MeCN)2] from SnF2 and I2 in MeCN.
We have found that this provides a convenient entry into
the chemistry of SnF4, and recently reported the synthesis
and detailed spectroscopic and structural studies of a series
of tin(IV) fluoride complexes of phosphane- or arsane ox-
ides, including [SnF4(R3EO)2] (R3EO = Ph3PO, Ph3AsO,
Me3PO or Me3AsO) and [SnF4(L–L)] {L–L = o-C6H4-
[P(O)Ph2]2, o-C6H4[P(O)Me2]2 or Ph2P(O)CH2P(O)Ph2}.[19]
These studies showed that toward pnictogen oxide ligands,
SnF4 was the strongest Lewis acid of the four tin(IV) ha-
lides, evidenced by shorter Sn–O and longer P–O bonds and
larger 31P NMR coordination shifts in the fluorides, com-
pared to corresponding data in complexes with the heavier
halides. Here we report the first investigations of the synthe-
sis, structures and spectroscopy of tin(IV) fluoride adducts
with tertiary phosphanes and arsanes. Comparisons of
these complexes with SnF4 species containing N- or O do-
nor ligands and with the heavier SnIV halides are described.
Introduction
Tin(IV) chloride is widely used in synthesis both as a
source of tin(IV) and as a strong Lewis acid.[1,2] A very
wide range of adducts of SnCl4 with neutral ligands (L) are
known, mostly six-coordinate [SnCl4L2], and similar com-
plexes are formed by SnBr4 and SnI4, although Lewis acid-
ity decreases SnCl4 Ͼ SnBr4 ϾϾ SnI4. The majority of
these ligands have hard O or N donor atoms, but examples
with softer P, As, S, Se or Te donors have also been charac-
terised.[3–10] In marked contrast little is known about ad-
ducts of SnF4 with neutral ligands. Some examples were
reported in the period 1950–1975, often as part of larger
surveys including the heavier tin(IV) halides, but little data
were provided and only a single complex, [SnF4(2,2Ј-bipy)],
was structurally characterised.[11–16] There appear to be no
reports of SnF4 complexes with softer donor ligands. This
neglect in part is similar to that of other p-block fluorides,
whose Lewis acidity, except towards F– or in superacid me-
dia (for MF5, M = As or Sb), is little explored, but also
reflects the more difficult synthetic entry into the com-
plexes. The SnX4 (X = Cl, Br or I) are tetrahedral molecules
readily soluble in weak or non-coordinating solvents such
as chlorocarbons, hydrocarbons or arenes, and synthesis of
[SnX4(L)2] usually involves simply mixing the constituents
in a solvent with precautions to avoid hydrolysis. In con-
trast, SnF4 has a polymeric structure based upon vertex
sharing SnF6 octahedra,[17] and although readily hydro-
Results and Discussion
Phosphane Complexes: The reactions of [SnF4(MeCN)2]
with PMe3 or PCy3 (L), in anhydrous dichloromethane un-
der a dinitrogen atmosphere yielded [SnF4L2] complexes in
moderate to good yields. However we were unable to obtain
a pure sample of [SnF4(PPh3)2] by this route. Since neither
the [SnF4(MeCN)2] nor the resulting complexes are easily
soluble in this solvent, some care is needed to obtain pure
[a] School of Chemistry, University of Southampton,
Southampton SO17 1BJ, UK
Eur. J. Inorg. Chem. 2006, 2773–2782
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2773

M. F. Davis, M. Clarke, W. Levason, G. Reid, Michael Webster
FULL PAPER
products. The complexes are both moisture and dioxygen Table 2. Selected bond lengths [Å] and angles [°] for trans-
[SnF4(PCy3)2].[a]
sensitive in solution, although the dry solids only slowly
decomposed in air (see below). They are much less soluble
in chlorocarbons than corresponding complexes of the
heavier tin halides, and prone to retain lattice solvent as
Sn1–F1
Sn1–P1
P1–C7
F1–Sn1–F2
F1–Sn1–P1
C1–P1–C7
C1–P1–C13
Sn1–P1–C7
F1–Sn1–P1–C1
1.959(2)
2.6538(11)
1.845(4)
91.21(10)
89.86(7)
108.09(17)
107.96(17)
113.77(12)
–60.0(2)
Sn1–F2
P1–C1
P1–C13
F1–Sn1–F2a
F2–Sn1–P1
C7–P1–C13
Sn1–P1–C1
Sn1–P1–C13
F1–Sn1–P1–C7
1.980(2)
1.860(4)
1.851(4)
88.79(10)
88.24(7)
104.81(16)
112.95(12)
108.81(12)
63.7(2)
1
evidenced in their H NMR spectra and in some of the X-
ray structures.[19] [SnF4(THF)2][18] was also explored as a
synthon, but appeared to have no advantages over the ace-
tonitrile complex. We also reacted [SnF4(MeCN)2] with
molten PPh3, but the 31P{1H} and 19F{1H} NMR spectra
showed a complex mixture of products, and it appears that
some fluorination of the phosphane occurs under these
conditions. The [SnF4L2] complexes were identified as trans
isomers from their 19F{1H} and 31P{1H} NMR spectra
F1–Sn1–P1–C13 –179.9(2)
[a] Symmetry operation, a: –x, –y, 2–z.
The corresponding reactions of [SnF4(MeCN)2] with the
Me2P(CH2)2PMe2, Et2P(CH2)2PEt2,
with weak satellites due to 119Sn and 117Sn (117Sn: I = 1/2, Cy2P(CH2)2PCy2, o-C6H4(PPh2)2, Ph2P(CH2)2PPh2 and
7.7%, Ξ = 35.63 MHz; 119Sn: I = 1/2, 8.6%, Ξ = o-C6H4(PMe2)2
(L–L) gave [SnF4(L–L)]. The
which are respectively triplets and quintets [in each case diphosphanes
37.27 MHz)] (Table 1). The 119Sn NMR spectra are 15-line [SnF4{Me2P(CH2)2PMe2}] was essentially insoluble in chlo-
patterns (triplet of quintets) with the coupling constants rocarbons or nitromethane and decomposed by DMSO,
shown in Table 1. The structure of [SnF4(PCy3)2] was deter- and although it appeared to be similar to the other exam-
mined and shows (Table 2, Figure 1) a centrosymmetric ples, we were unable to obtain any solution spectroscopic
molecule with Sn–P = 2.654(1) Å and Sn–F = 1.959(2), data and it will not be discussed further. The other exam-
1.980(2) Å. The Sn–P is longer than that in trans- ples are as expected cis isomers showing doublet of doublets
[SnCl4(PEt3)2] [2.615(5) Å],[20] and marginally longer than of triplets in their 31P{1H} NMR spectra and two 19F{1H}
in trans-[SnCl4{κ1-Ph2PCH2PPh2}2] [2.649(1) Å],[21] but resonances, a triplet of triplets for the Ftrans-F and a doublet
shorter than found in trans-[SnI4(PiPr3)2] [2.69(1) Å],[22] al- of doublet of triplets for the Ftrans-P, with the coupling con-
though the differing steric requirements of the three phos- stants shown in Table 1 (again all resonances have tin satel-
phanes preclude a more detailed discussion.
lites). The 119Sn NMR resonances of the diphosphane com-
Table 1. Selected NMR spectroscopic data for SnF4 complexes.[a]
Compound
δ(31P{1H})[b]
–37.8 (t,d,d)
∆P[c] δ(119Sn)[d]
δ(19F{1H})
1J(19F-119Sn) nJ(31P-19F)
2J(19F-19F) nJ(31P-119Sn)
[SnF4{o-C6H4(PMe2)2}]
17
–657.6 (t,t,t) –131.7 (t,t)
–161.1 (d,d,t)
2470
2160
2627
2207
2745
2993
2552
2183
2644
2205
2650
2212
1964
1978
1987
1982
117, 98, 54 42
1520
[SnF4{o-C6H4(PPh2)2}]
–18.9 (t,d,d)
–6
–665.9 (t,t,t) –123.8 (t,t)
–155.5 (d,d,t)
93, 73, 48
52
1512
trans-[SnF4(Me3P)2]
trans-[SnF4(Cy3P)2]
[SnF4{Et2P(CH2)2PEt2}]
–19.1 (q)
+22.2 (q)
–11.6 (t,d,d)
43
11
6
–628.0 (t,q)
–628.5 (t,q)
–649.4 (t,t,t) –123.8 (t,t)
–150.2 (d,d,t)
–132.8 (t)
–98.9 (t)
155
124
2975
2530
1628
110, 95, 46 40
[SnF4{Cy2P(CH2)2PCy2}]
[SnF4{Ph2P(CH2)2PPh2}]
[SnF4(2,2Ј-bipyridyl)]
[SnF4(1,10-phen)]
–9.9 (t,d,d)
–12 –639.1 (t,t,t) –113.7 (t,t)
–139.5 (d,d,t)
98, 88, 46 46
1528
1630
–17.8 (t,d,d)
–4
–668.1 (t,t,t) –112.4 (t,t)
–147.1 (d,d,t)
118, 87, 44 46
–708.2 (t,t)
–149.8 (t)
–179.8 (t)
–149.5 (t)
–180.8 (t)
48
50
–715.1 (t,t)
[SnF4(THF)2] (220 K)
trans isomer
cis isomer
–775.4 (q)
–775.3 (t,t)
–166.7 (s)
–166.2 (t)
–178.8 (t)
–163.8 (s)
–167.8 (t)
–184.4 (t)
–181.0 (s)
–167.1
1910
1918
2074
1983
2266
2096
n.o.
54
50
61
trans-[SnF4(pyridine)2]
[SnF4{Me2N(CH2)2NMe2}]
–670.8 (q)
[e]
[SnF4(MeCN)2]
[SnF4{MeO(CH2)2OMe}]
(190 K)
n.o.[f]
–753.8 (t,t)
2233
2189
–183.3
[a] In CH2Cl2/10% CDCl3. [b] Ligand chemical shifts are: o-C6H4(PMe2)2 –55 ppm; o-C6H4(PPh2)2 –13 ppm; Ph2P(CH2)2PPh2 –13 ppm;
Et2P(CH2)2PEt2 –18 ppm; Me2P(CH2)2PMe2 –48 ppm; Cy2P(CH2)2PCy2 +2 ppm; PMe3 –62 ppm; PCy3 +11.5 ppm. [c] Coordination shift
(δcomplex –δligand). [d] 119Sn NMR spectra were typically recorded at 250 K. [e] Insufficently soluble to record spectrum. [f] n.o. = not
observed in temperature range 295–180 K.
2774
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2773–2782

SnF4 Complexes with PR3 Ligands. Comparision of Hard and Soft Donor Ligands
FULL PAPER
Figure 2. Structure of [SnF4{Et2P(CH2)2PEt2}] showing the atom
numbering scheme. Ellipsoids are drawn at the 50% probability
level and H atoms omitted for clarity. A twofold axis passes
through Sn1 and the centre of the C1–C1a bond. Symmetry opera-
tion, a: –x, y, 1/2–z.
Figure 1. Structure of trans-[SnF4(PCy3)2] showing a partial atom
numbering scheme. Cyclohexyl groups are numbered cyclically
starting at the P-bonded C atom. Ellipsoids are drawn at the 50%
probability level and H atoms omitted for clarity. Sn1 is positioned
on a centre of symmetry. Symmetry operation, a: –x, –y, 2–z.
Other SnF4 Complexes: A small number of complexes of
hard N- or O-donor ligands, previously obtained directly
from SnF4, were re-prepared in this study for comparison
purposes from [SnF4(MeCN)2], viz [SnF4(L–L)] (L–L =
2,2Ј-bipyridyl, 1,10-phenanthroline, N,N,NЈNЈ-tetramethyl-
ethanediamine and 1,2-dimethoxyethane) and [SnF4(pyrid-
ine)2]. The complexes with N donor ligands are unaffected
by exposure to air for several hours, although moisture-sen-
sitive in solution. They are much less readily decomposed
than the phosphane complexes. The solid [SnF4(L)2] [L =
THF or L2 = MeO(CH2)2OMe] are very deliquescent. The
19F{1H} and 119Sn NMR spectroscopic data are shown in
Table 1. Although the ranges overlap, there is a general shift
to lower frequency in the 119Sn NMR shifts with donor, P
Ǟ N Ǟ O. The complexes with L–L = 2,2Ј-bipyridyl, 1,10-
phenanthroline, Me2N(CH2)2NMe2 have the expected cis
geometry, whilst the [SnF4(pyridine)2] is the trans isomer.
In contrast to the N donor complexes, the ether adducts,
[SnF4{MeO(CH2)2OMe}] and [SnF4(THF)2], are under-
going rapid neutral ligand exchange in solution at ambient
temperatures, and only at low temperatures was it possible
to record 19F{1H} and 119Sn NMR spectroscopic data.
These revealed that in CH2Cl2 solution at 220 K the THF
complex was a mixture of cis and trans isomers in approxi-
mately equal amounts. On the basis of IR and Mössbauer
data Tudela[18] concluded that the [SnF4LЈ2] (LЈ = pyridine
or THF) were trans isomers in the solid state. Crystals of
[SnF4{MeO(CH2)2OMe}] and [SnF4(1,10-phenanthroline)]
were grown from CH2Cl2/n-hexane. The structure of the
former shows (Table 4, Figure 3) the expected cis geometry
with Sn–O = 2.156(2), 2.144(2) Å, which are shorter than
those in trans-[SnCl4(THF)2][23] but significantly longer
than the Sn–O distances in phosphane oxide adducts of
plexes are 27-line patterns (triplet of triplets of triplets), the
spectra typically being recorded at 250 K to reduce any line
broadening due to the onset of reversible ligand dissoci-
ation. The modest solubility necessitated long accumula-
tions, and in some cases the weakest outer lines of the mul-
tiplets were rather unclear, although the various couplings
were readily extracted (Table 1). The trends in the various
NMR parameters will be discussed in a later section in
comparison with those of related complexes (see below).
The structure of [SnF4{Et2P(CH2)2PEt2}] was determined
and confirms the cis geometry deduced from the NMR
studies (Table 3, Figure 2). The Sn–P distance is 2.606(1) Å,
shorter than in the trans-[SnF4(PCy3)2] [2.654(1) Å], and
also shorter than the value in cis-[SnCl4{Et2P(CH2)2PEt2}]
[2.648(2) Å] described below. The Sn–Ftrans-F 1.986(2) Å is
significantly longer than Sn–Ftrans-P 1.953(2) Å, a pattern
which is found in most adducts of SnX4 (X = Cl, Br or I)
with soft donor ligands.[6–10]
Table 3. Selected bond lengths [Å] and angles [°] for
[SnF4{Et2P(CH2)2PEt2}].[a]
Sn1–F1
Sn1–F2
Sn1–P1
P1···P1a
F1–Sn1–F2
F1–Sn1–F2a
F1–Sn1–F1a
F2–Sn1–F2a
P1–Sn1–P1a
Sn1–P1–C2
1.9863(17)
1.9532(16)
2.6058(9)
3.409(2)
92.60(7)
91.36(7)
174.29(10)
92.29(10)
81.70(4)
P1–C1
P1–C2
P1–C4
1.821(3)
1.815(3)
1.814(3)
P1–Sn1–F1
P1–Sn1–F2
P1–Sn1–F1a
P1–Sn1–F2a
Sn1–P1–C1
Sn1–P1–C4
84.66(5)
93.14(6)
91.02(5)
173.40(5)
102.52(9)
116.34(10)
114.54(10)
[a] Symmetry operation, a: –x, y, ½–z.
Eur. J. Inorg. Chem. 2006, 2773–2782
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2775

M. F. Davis, M. Clarke, W. Levason, G. Reid, Michael Webster
FULL PAPER
SnF4, which lie in the range of ca. 2.045(3)–2.088(5) Å.[18] may be compared with that of [SnCl4(1,10-phenan-
The latter complexes show no dissociation in solution, throline)],[24] which possess Sn–N = 2.234(7)–2.251(8) Å.
which is indicative of stronger binding of the phosphane One can also compare the literature data on [SnX4(2,2Ј-
oxide ligands compared to the ethers. The differences in the bipyridyl)] for which Sn–N are X = F [2.181(3), 2.183(3) Å],
distances Sn–Ftrans-F [1.926(2), 1.927(2) Å] and Sn–Ftrans-O X = Cl [2.247(4), 2.226(4) Å], X = Br [2.23(1), 2.23(1) Å],
[1.921(2), 1.923(2) Å] are much less than in the phosphane X = I [2.28(2) Å].[16,25,26] The 2,2Ј-bipyridyl series shows the
complex described previously. The structure of [SnF4(1,10- longest Sn–N bonds in the iodide and the shortest in the
phenanthroline)] [Sn–N = 2.157(7) Å] (Table 5, Figure 4) fluoride, with the chloride and bromide less clearly discrimi-
nated, support for the fluoride being the strongest Lewis
acid of the four halides.
Table 4. Selected bond lengths [Å] and angles [°] for
[SnF4{MeO(CH2)2OMe}].
Table 5. Selected bond lengths [Å] and angles [°] for [SnF4(1,10-
phenanthroline)]·MeOH.[a]
Sn1–F1
Sn1–F2
Sn1–O1
O1–C1
1.9263(17)
1.9210(18)
2.1559(19)
1.463(3)
Sn1–F3
Sn1–F4
Sn1–O2
O2–C3
O2–C4
O1···O2
1.9274(17)
1.9234(18)
2.144(2)
1.454(3)
1.463(3)
2.673(3)
Sn1–F1
Sn1–F2
N1···N1a
F1–Sn1–F2
F2–Sn1–F2a
F1–Sn1–N1
N1–Sn1–N1a
Sn1–N1–C1
1.887(5)
1.860(6)
2.670(13)
93.3(3)
99.2(4)
88.0(3)
Sn1–N1
N1–C1
N1–C6
F1–Sn1–F2a
F1–Sn1–F1a
F2–Sn1–N1
2.157(7)
1.339(11)
1.349(10)
91.9(3)
172.0(3)
168.4(3)
O1–C2
1.456(3)
C2–C3
F2–Sn1–F4
1.502(4)
99.27(8)
F1–Sn1–F3 170.07(7)
F–Sn1–F (the rest) 92.09(8)–93.93(8) O2–Sn1–O1 76.88(8)
76.5(3)
126.4(5)
F2–Sn1–O2
169.84(8)
F4–Sn1–O1 167.62(8)
Sn1–N1–C6
115.1(5)
F–Sn1–O (the rest) 84.27(8)–93.07(8)
[a] Symmetry operation, a: 1–x, 1/2–y, z.
Sn1–O1–C1
Sn1–O1–C2
O1–C2–C3
117.34(18)
111.60(15)
107.0(2)
Sn1–O2–C3 112.38(17)
Sn1–O2–C4 121.09(17)
O2–C3–C2
106.5(2)
Figure 4. Structure of [SnF4(1,10-phenanthroline)]·MeOH showing
the atom numbering scheme. Ellipsoids are drawn at the 40% prob-
ability level and H atoms omitted for clarity. The tin atom is on a
twofold axis. Symmetry operation, a: 1–x, 1/2–y, z.
Other Tin(IV) Halide Adducts: For comparison several
new complexes of SnX4 (X = Cl, Br or I) with phosphane or
arsane ligands were also prepared, in these cases by direct
reaction of SnX4 with the appropriate ligand in anhydrous
Figure 3. Structure of [SnF4{MeO(CH2)2OMe}] showing the atom
numbering scheme. Ellipsoids are drawn at the 50% probability
level and H atoms omitted for clarity.
Table 6. Selected NMR spectroscopic data for SnX4 (X = Cl, Br or I) complexes.[a]
Compound
δ(31P{1H})[b]
∆P[c]
δ(119Sn)[d]
1J(31P-119Sn)
Ref.
[SnCl4{o-C6H4(PMe2)2}]
[SnBr4{o-C6H4(PMe2)2}]
[SnI4{o-C6H4(PMe2)2}]
–28.1
–31.9
–59.5 (243 K)
–4.9
–20.9
–18.8
–13.9
–
–
–
27
23
–5
13
27
–5.5
–1
–
–616 (t)
–1188 (t)
n.o.[e]
945
581
240
1049
1005
890
890
–
this work
this work
this work
[SnCl4{Et2P(CH2)2PEt2}]
[SnCl4{Me2P(CH2)2PMe2}]
[SnCl4{Ph2P(CH2)2PPh2}]
[SnCl4{o-C6H4(PPh2)2}]
[SnCl4{o-C6H4(AsMe2)2}]
[SnBr4{o-C6H4(AsMe2)2}]
[SnCl4{MeC(CH2AsMe2)3}]
[SnBr4{MeC(CH2AsMe2)3}]
–615 (t)
–617 (t)
–626 (t)
–607.5 (t)
–675 (s)
–1354 (s)
–696 (s)
–1290 (s)
this work
[9]
[9]
[9]
[9]
[9]
–
–
–
–
–
–
this work
this work
–
[a] In CH2Cl2/10% CDCl3. [b] Ligand chemical shifts are: o-C6H4(PMe2)2 –55 ppm; o-C6H4(PPh2)2 –13 ppm; Ph2P(CH2)2PPh2 –13 ppm;
Et2P(CH2)2PEt2 –18 ppm; Me2P(CH2)2PMe2 –48 ppm; Cy2P(CH2)2PCy2 +2 ppm; PMe3 –62 ppm; PCy3 +11.5 ppm. [c] Coordination
shift (δcomplex –δligand). [d] 119Sn NMR spectra were typically recorded at 250 K. [e] n.o. = not observed in temperature range 295–180 K.
2776
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2773–2782

SnF4 Complexes with PR3 Ligands. Comparision of Hard and Soft Donor Ligands
FULL PAPER
dichloromethane, and the NMR spectra were recorded oxygen, and whilst the mechanism remains obscure, the use
(Table 6). Like other complexes of this type, they are very of 18O2 in these reactions showed that the source of the
moisture sensitive and also dioxygen sensitive to varying oxygen is O2, not water as in a halogenation/hydrolysis
degrees in solution,[9,27] but also much more soluble in chlo- mechanism.[27] The phosphane complexes of tin(IV) fluo-
rocarbons than their tin(IV) fluoride analogues. The 119Sn ride made in the present study also show varying degrees of
chemical shifts are surprisingly similar for corresponding oxygen sensitivity, especially in solution. The [SnF4(PCy3)2]
complexes of SnF4 and SnCl4, but those of SnBr4 and SnI4 is particularly sensitive and even brief exposure to air of a
show much more deshielded resonances (Table 6). The CH2Cl2 solution produced substantial oxidation. The
1J(119Sn-31P) coupling constants fall with halogen F Ͼ Cl [SnF4(PMe3)2] and the diphosphane complexes are less
Ͼ Br Ͼ I. The structure of cis-[SnCl4{Et2P(CH2)2PEt2}] rapidly air-oxidised, but modest amounts of phosphane ox-
was determined (Table 7, Figure 5) and provides a direct ides can be detected by 31P NMR in solutions exposed to
comparison with the fluoride structure discussed above. air for some hours. In these systems the phosphane oxide
Again there is a marked difference between Sn–Cltrans-Cl binds strongly to the SnF4 (cf. ref.[19]), and thus in contrast
[2.453(1) Å] and Sn–Cltrans-P [2.408(1) Å] with Sn–P = to the extensively dissociated SnI4 systems[27] the formation
2.648(2) Å. Other structurally characterised phosphane of phosphane oxide is stoichiometric, because the phos-
complexes of SnCl4 are trans-[SnCl4(PEt3)2] [Sn–P = phane oxides remove the SnF4 by complexation preventing
2.615(5) Å],[20] trans-[SnCl4(κ1-Ph2PCH2PPh2)2] [Sn–P = further reaction. Crystals of [SnF4(OPPh3)2] were obtained
2.649(1) Å],[21] and cis-[SnCl4{Ph2P(CH2)2PPh2}] [Sn–P = over several days from a CH2Cl2 solution of the products
2.679(2), 2.653(2) Å, Sn–Cl = 2.402(2), 2.406(2), 2.408(2), of melting [SnF4(MeCN)2] with excess PPh3. The structure
2.447(2) Å].[28]
(Figure 6, Table 8) shows it to be the trans isomer, and the
bond lengths are entirely in keeping with our previous con-
clusions[19] that SnF4 is the strongest Lewis acid of the four
tin(IV) halides towards O donor phosphane oxide ligands.
Table 7. Selected bond lengths [Å] and angles [°] for
[SnCl4{Et2P(CH2)2PEt2}].[a]
Sn1–Cl1
Sn1–Cl2
P1–C4
P1···P1a
Cl1–Sn1–Cl2
Cl1–Sn1–Cl1a
Cl1–Sn1–P1
P1–Sn1–P1a
Sn1–P1–C4
2.4529(14)
2.4084(14)
1.824(6)
3.422(3)
90.16(5)
174.00(7)
84.19(5)
80.49(7)
114.0(2)
Sn1–P1
P1–C2
P1–C5
2.6481(17)
1.821(6)
1.825(5)
Cl1–Sn1–Cl2a 93.97(5)
Cl2–Sn1–Cl2a 92.99(7)
Cl2–Sn1–P1
Sn1–P1–C2
Sn1–P1–C5
171.65(5)
117.0(2)
102.09(18)
P1–C5–C5a–P1a 67.7(6)
[a] Symmetry operation, a: 1–x, y, 1/2–z.
Figure 6. Structure of trans-[SnF4(Ph3PO)2] showing a partial atom
numbering scheme. Phenyl groups are numbered cyclically starting
at the ipso C atom. Ellipsoids are drawn at the 50% probability
level and H atoms omitted for clarity. Sn1 is positioned on a centre
of symmetry. Symmetry operation, a: –x, 1–y, 1–z.
Table 8. Selected bond lengths [Å] and angles [°] for trans-
[SnF4(Ph3PO)2]·2CH2Cl2.
Sn1–F1
Sn1–F2
P1–C1
P1–C13
F1–Sn1–F2
F2–Sn1–O1
O1–P1–C1
O1–P1–C13
1.928(3)
1.934(3)
1.792(5)
1.797(6)
90.56(12)
91.79(13)
108.0(2)
111.4(2)
Sn1–O1
O1–P1
P1–C7
2.050(3)
1.523(3)
1.795(5)
F1–Sn1–O1
Sn1–O1–P1
O1–P1–C7
89.06(13)
146.3(2)
112.5(2)
Figure 5. Structure of [SnCl4{Et2P(CH2)2PEt2}] showing the atom
numbering scheme. Ellipsoids are drawn at the 40% probability
level and H atoms omitted for clarity. The tin atom is on a twofold
axis. Symmetry operation, a: 1–x, y, 1/2–z.
Reactions with Dioxygen: We have reported elsewhere[9]
Attempted Preparation of Tertiary Arsane Complexes: In
that mixtures of phosphanes or diphosphanes and SnX4 (X contrast to the results with phosphane ligands, repeated
= Cl, Br or I) in chlorocarbon solution air-oxidise readily attempts to isolate complexes of SnF4 with tertiary arsanes
to the corresponding phosphane oxides. Catalytic amounts including AsMe3, o-C6H4(AsMe2)2 and MeC(CH2AsMe2)3
of SnI4 can be used to cleanly generate phosphane oxides were unsuccessful. The reaction of [SnF4(MeCN)2] or
from the corresponding phosphanes using dry air or di- [SnF4(THF)2] in CH2Cl2 or toluene with o-C6H4(AsMe2)2,
Eur. J. Inorg. Chem. 2006, 2773–2782
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2777

M. F. Davis, M. Clarke, W. Levason, G. Reid, Michael Webster
Table 9. Selected bond lengths [Å] and angles [°] for [SnBr4{MeC(CH2AsMe2)3}].
FULL PAPER
Sn1–Br1
Sn1–Br2
2.5708(6)
2.5479(5)
Sn1–Br3
Sn1–Br4
2.6340(5)
2.5807(5)
Sn1–As1
As1–C6
2.6932(5)
1.930(4)
Sn1–As2
As2–C8
2.7095(6)
1.935(3)
As1–C7
As3–C10
As1–C3
1.932(3)
1.966(3)
1.953(4)
As2–C9
As3–C11
As2–C4
1.928(3)
1.972(3)
1.954(3)
As3–C5
1.987(3)
As1···As2
Br3–Sn1–Br4
Br1–Sn1–As2
As1–Sn1–As2
C–As2–C
3.712(1)
Br–Sn1–Br (ca. 90°)
Br–Sn1–As (ca. 90°)
Br2–Sn1–As1
C–As1–C
91.979(17)–94.850(17)
82.905(16)–90.337(16)
174.623(16)
101.08(16)–108.21(15)
93.50(15)–98.69(16)
170.563(15)
173.739(14)
86.791(16)
99.62(13)–107.75(14)
C–As3–C
which is a very strongly coordinating ligand towards many 2.5479(5) Å], and with the axial Br–Sn–Br unit bent
d-block metals,[29] resulted in white solids of variable com- towards the neutral ligand (Br3–Sn1–Br4 = 170.6°), as
position which appeared to be mixtures of the starting com- found in tin(IV) halide structures with a variety of soft do-
plex, possibly [SnF4{o-C6H4(AsMe2)2}] and SnF4. The IR nors.[6–9] The Sn–As [2.6932(5), 2.7095(6) Å] are slightly
spectra showed the presence of the diarsane, a broad υ(SnF) shorter than those in the only other structurally character-
1
at ca. 570 cm–1, and usually some MeCN or THF. The H ised tin–arsane complexes [SnI4{o-C6H4(AsMe2)2}]
NMR spectra of these products in CD2Cl2 solution showed [2.716(2),
2.752(2) Å],[9]
and
trans-[SnCl4(AsPh3)2]
only MeCN or THF and “free” o-C6H4(AsMe2)2 [as o- [2.762(1) Å].[30] The wide As–Sn–As angle [86.79(2)°] in the
C6H4(AsMe2)2 is a liquid, this is evidence for coordination present complex reflects the six-membered chelate ring
of the diarsane to tin in the solids]. The 19F{1H} NMR present and compares with 78.43(7)° in [SnI4{o-
spectra showed no resonances at room temperature, but be- C6H4(AsMe2)2}] which contains a five-membered ring.
low ca. 210 K, two new broad resonances at δ = –138 and
–152 were observed, which seem reasonable for [SnF4{o-
C6H4(AsMe2)2}], but no F–F coupling was resolved even at
190 K. The data suggest that [SnF4{o-C6H4(AsMe2)2}]
forms in the reaction, but that it is extensively dissociated
in solution and even use of a substantial excess of diarsane
does not produce a pure product. In the cases of AsMe3 or
MeC(CH2AsMe2)3 there was little evidence for coordina-
tion to SnF4. In contrast, arsane complexes of SnX4 (X =
Cl, Br or I) form readily,[9] and indeed [SnI4{o-
C6H4(AsMe2)2}] is one of the very small number of struc-
turally characterised neutral ligand adducts of SnI4. The
explanation of this marked difference to phosphanes proba-
bly arises from the fact the SnF4 is a very hard Lewis acid
Figure 7. Structure of [SnBr4{MeC(CH2AsMe2)3}] showing the
with contracted tin acceptor orbitals, and correspondingly
has less ability to bind the large soft arsenic centre. For
many transition-metal systems the differences between
binding corresponding phosphanes and arsanes is small,
but becomes very significant with high oxidation state and/
or harder metal centres of the 3d series such as FeIV, NiIV
or MnII, where the phosphanes result in significantly more
atom numbering scheme. Ellipsoids are drawn at the 50% prob-
ability level and H atoms omitted for clarity.
Comparisons and Conclusions
This work has provided the first examples of SnF4 ad-
stable complexes.[29] Our results suggest similar discrimi- ducts with soft phosphane ligands and also a considerable
nation by SnF4.
amount of spectroscopic and structural data on comparable
In the course of this work the [SnX4{MeC(CH2As- complexes with hard N- or O-donor ligands and with the
Me2)3}] (X = Cl or Br) were prepared from the appropriate heavier tin(IV) halides. The structural data discussed in pre-
1
SnX4 and triarsane in CH2Cl2 and their H NMR spectra ceding sections clearly show that for a fixed hard neutral
show the triarsane bound as a bidentate to a six-coordinate ligand the Sn–ligand bond lengths are shortest in the fluo-
tin centre. The 119Sn NMR chemical shifts of δ = –696 ride complexes, consistent with SnF4 being the strongest
and –1290 ppm (Table 6) are typical of SnX4As2 donor Lewis acid. The corresponding data for cis-
sets.[9] The structures were confirmed by a X-ray study of [SnX4{Et2P(CH2)2PEt2}] (X = F or Cl), which are exact
[SnBr4{MeC(CH2AsMe2)3}] (Table 9, Figure 7), which analogues (isostructural), also show the shortest Sn–P bond
showed a distorted octahedral tin centre with Sn–Brtrans-Br in the fluoride, indicating that similar trends hold with the
[2.5807(5), 2.6340(5) Å] longer than Sn–Brtrans-As [2.5708(6), soft (but strong σ-donor) phosphorus. The longer Sn–P
2778
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2773–2782

SnF4 Complexes with PR3 Ligands. Comparision of Hard and Soft Donor Ligands
FULL PAPER
togyric ratio of the isotope. Microanalytical measurements on new
complexes were performed by the microanalytical service at Strath-
clyde University.
bond in trans-[SnF4(PCy3)2] is almost certainly due to steric
effects caused by the bulky cyclohexyl substituents (PCy3
has a cone angle of ca. 170°). However, the instability of
SnF4 adducts of arsanes suggests that towards even softer
ligands, SnCl4 will be more strongly coordinated.
[SnF4{o-C6H4(PMe2)2}]: [SnF4(MeCN)2] (0.276 g, 1.0 mmol) was
dissolved in CH2Cl2 (20 mL) and o-C6H4(PMe2)2 (0.198 g,
1.0 mmol) added and the mixture stirred overnight at ambient tem-
peratures. The white precipitate was filtered off and dried in vacuo.
Yield 0.205 g, 52%. C10H16F4P2Sn·CH2Cl2 (477.8): calcd. C 27.6,
These studies have also produced a wealth of NMR spec-
troscopic data (Table 1 and Table 6), but although several
empirical trends in the chemical shifts and coupling con-
stants with change in halide or neutral ligand can be dis-
cerned, the patterns are complicated, indicating several
competing factors are present. Thus, the 119Sn chemical
shifts show consistent low frequency shifts with X: Cl Ǟ F
Ǟ Br Ǟ I, the same as observed in halostannates(IV),[31,32]
evidence that electronegativity is not the dominant fac-
tor.[33] Low frequency shifts also occur with neutral donor
atoms P Ǟ N Ǟ O. The 31P chemical shifts and the coordi-
nation shifts (δcomplex –δligand) for the phosphane complexes
are not systematic with changes in halide co-ligand. Al-
though phosphanes mostly show high frequency coordina-
tion shifts when bound to transition metals, both high and
low frequency shifts have been observed in p-block element
complexes, and the reasons remain obscure.[33,34] The
1J(31P-119Sn) coupling constants are largest for the fluorides
1
H 3.8; found C 26.9, H 3.8. H NMR (300 MHz, CDCl3, 25 °C):
2
δ = 1.87 (t, J+5JP–H = 4 Hz, 12 H, Me), 5.4 (CH2Cl2), 7.75–7.81
(m, 4 H, C H ) ppm. IR (Nujol): ν = 564 (s), 534 (s) υ(SnF) cm–1.
˜
6
4
[SnCl4{o-C6H4(PMe2)2}]: A solution of SnCl4 (0.12 mL, 1.0 mmol)
in CH2Cl2 (5 mL) was added to o-C6H4(PMe2)2 (0.198 g, 1.0 mmol)
in CH2Cl2 (20 mL) producing an immediate white precipitate. After
30 min the solid was filtered off and dried in vacuo. Yield 0.427 g,
93%. C10H16Cl4P2Sn (458.7): calcd. C 26.2, H 3.5; found C 25.9,
1
2
H 3.2. H NMR (300 MHz, CDCl3, 25 °C): δ = 1.97 (t, J+5JP–H
= 4.4 Hz, 12 H, Me), 7.75–7.81 (m, 4 H, C6H4) ppm. IR (Nujol):
ν = 307 (s), 296 (s) υ(SnCl) cm–1.
˜
[SnBr4{o-C6H4(PMe2)2}]: Prepared similarly to the chloride as a
yellow solid. Yield 93%. C10H16Br4P2Sn (636.5): calcd. C 18.9, H
1
2.5; found C 18.7, H 2.4. H NMR (300 MHz, CDCl3, 25 °C): δ =
1.95 (t, 2J+5JP–H = 4.5 Hz, 12 H, Me), 7.75–7.81 (m, 4 H,
C H ) ppm. IR (Nujol): ν = 205 (sh), 202 (s), 199 (sh), 196 (s)
˜
6
4
and much larger for trans-P–Sn–P than for cis-P–Sn–P ar- υ(SnBr) cm–1.
rangements (Table 1), whilst the 1J(19F-119Sn) couplings are
[SnI4{o-C6H4(PMe2)2}]: Prepared similarly to the chloride as a
larger in the phosphane complexes than in the N- or O-
brown powder. Yield 80%. C10H16I4P2Sn (824.5): calcd. C 14.6, H
1
donor ligand cases. The J(19F-119Sn)F–trans-F are markedly
1
2.0; found C 14.6, H 1.9. H NMR (300 MHz, CDCl3, 25 °C): δ =
larger than 1J(19F-119Sn)F–cis-F in the phosphane complexes,
but this difference is small or absent in the complexes with
harder donor co-ligands. A more detailed understanding of
the factors responsible for these trends must await further
work on related systems.
1.83 (t, 2J+5JP–H = 4.8 Hz, 12 H, Me), 7.75–7.81 (m, 4 H,
C6H4) ppm.
[SnF4{o-C6H4(PPh2)2}]: [SnF4(MeCN)2] (0.276 g, 1.00 mmol) was
suspended in CH2Cl2 (20 mL) and a solution of o-C6H4(PPh2)2
(0.446 g, 1.00 mmol) in CH2Cl2 (5 mL) added and the mixture
stirred for 8 h at ambient temperatures. The white precipitate was
filtered off and dried in vacuo. Yield 0.17 g, 27%. C30H24F4P2Sn
(641.2): calcd. C 56.2, H 3.8; found C 56.9, H 4.1. 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 7.30–7.68 (m, Ph) ppm. IR (Nujol):
Given that stable complexes of soft phosphane donor li-
gands have now been prepared for the hard Lewis acid
SnF4, similar complexes should be obtainable for other
main-group fluorides. Studies to explore this are underway.
ν = 574 (s), 557 (s), 526 (s) υ(SnF) cm–1.
˜
[SnF4(PMe3)2]: [SnF4(MeCN)2] (0.277 g, 1.00 mmol) was sus-
pended in CH2Cl2 (10 mL), trimethylphosphane (0.167 g,
2.20 mmol) was added and stirred at room temperature for 1 h.
Some of the CH2Cl2 was removed in vacuo and then dry hexane
(20 mL) was added. A white solid precipitated out which was fil-
tered off under nitrogen and dried in vacuo. Yield 0.250 g, 68%.
C6H18F4P2Sn·2CH2Cl2 (516.7): calcd. C 18.6, H 4.3; found C 18.3,
Experimental Section
All compounds were made under dinitrogen using dry solvents and
standard Schlenk and glove box techniques. SnF2, SnCl4, SnBr4
and SnI4 were obtained from Aldrich and used as received.
[SnF4(MeCN)2] was made as described.[18] Ligands were obtained
from Aldrich: PMe3, PPh3, PCy3, AsMe3, Me2P(CH2)2PMe2,
Et2P(CH2)2PEt2, Cy2P(CH2)2PCy2, or were made by literature
methods: o-C6H4(PPh2)2, Ph2P(CH2)2PPh2, o-C6H4(PMe2)2, o-
C6H4(AsMe2)2, MeC(CH2AsMe2)3.[35–38] 2,2Ј-Bipyridyl and 1,10-
phenanthroline were dried by heating in vacuo, 1,2-dimethoxye-
thane was dried with sodium and freshly distilled. Pyridine and
Me2N(CH2)2NMe2 were dried by distillation from BaO, tetra-
hydrofuran was dried by distillation from Na-benzophenone ketyl,
MeCN and CH2Cl2 from CaH2. IR spectra were recorded as Nujol
1
H 4.5. H NMR (300 MHz, CDCl3, 25 °C): δ = 1.68 (m, Me), 5.4
(CH Cl ) ppm. IR (Nujol): ν = 546 (br) υ(SnF) cm–1.
˜
2
2
[SnF4(PCy3)2]: [SnF4(MeCN)2] (0.277 g, 1.00 mmol) was suspended
in CH2Cl2 (10 mL), tricyclohexylphosphane (0.588 g, 2.10 mmol)
was added and stirred at room temperature for 3 h. No precipi-
tation had occurred so the solution was reduced to ca. 5 mL in
vacuo and then dry hexane (5 mL) was added. A white solid pre-
cipitated out which was filtered off under nitrogen and dried in
vacuo. Yield 0.45 g, 60%. C32H66F4P2Sn·1/2CH2Cl2 (750.0): calcd.
1
mulls on a Perkin–Elmer PE 983G spectrometer, H NMR spectra
1
C 54.9, H 8.5; found C 54.4, H 8.8. H NMR (300 MHz, CDCl3,
in CDCl3, CD2Cl2 or CD3NO2 solutions on a Bruker AV300,
31P{1H}, 19F{1H} and 119Sn NMR spectra on a Bruker DPX400
and referenced to 85% H3PO4, CFCl3 and neat SnMe4 respectively.
The 119Sn NMR spectra were recorded from solutions containing
[Cr(acac)3] as a relaxation agent and without proton decoupling to
avoid NOE diminution of the signal due to the negative magne-
25 °C): δ = 1.29–2.34 (m, Cy), 5.4 (CH Cl ) ppm. IR (Nujol): ν =
˜
2
2
557 (s), 535 (s) υ(SnF) cm–1.
[SnF4{Et2P(CH2)2PEt2}]: [SnF4(MeCN)2] (0.278 g, 1.00 mmol) was
suspended in CH2Cl2 (20 mL), 1,2-bis(diethylphosphanyl)ethane
(0.28 mL, 1.20 mmol) was added dropwise and stirred for 1.5 h.
Eur. J. Inorg. Chem. 2006, 2773–2782
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2779

M. F. Davis, M. Clarke, W. Levason, G. Reid, Michael Webster
FULL PAPER
Table 10. Crystal data and structure refinement details.[a]
Compound
[SnF4(Ph3PO)2]·2CH2Cl2
[SnF4{Et2P(CH2)2PEt2}]
[SnF4{MeO(CH2)2OMe}]
Formula
M
C38H34Cl4F4O2P2Sn
921.08
C10H24F4P2Sn
400.92
C4H10F4O2Sn
284.81
Crystal system
Space group
a [Å]
monoclinic
P21/n (no. 14)
8.8697(16)
14.771(4)
14.446(4)
90
95.236(16)
90
1884.7(8)
2
monoclinic
C2/c (no. 15)
8.8994(12)
11.663(3)
14.774(4)
90
104.257(12)
90
1486.2(5)
4
monoclinic
P21/n (no. 14)
6.2957(15)
20.987(6)
6.693(2)
90
111.941(15)
90
820.2(4)
4
b [Å]
c [Å]
α [°]
β [°]
γ [°]
U [Å3]
Z
µ [mm–1
F(000)
]
1.101
924
1.956
800
3.137
544
Total no. of observations (Rint
Unique observations
)
)
)
21329 (0.138)
4312
0.681, 1.000
232, 0
0.98
–0.83 to +0.74
0.058, 0.106
0.135, 0.131
9486 (0.053)
1708
0.726, 1.000
78, 0
1.07
–0.64 to +0.69
0.030, 0.053
0.042, 0.056
6388 (0.037)
1867
0.651, 1.000
100, 0
1.14
–0.76 to +0.48
0.023, 0.054
0.027, 0.056
Min., max. transmission
No. of parameters, restraints
Goodness-of-fit on F2
Resid. electron density [e·Å–3
R1, wR2 [I Ͼ 2σ(I)][b]
R1, wR2 (all data)
]
Compound
[SnF4(1,10-phenanthroline)]·MeOH
[SnF4(PCy3)2]
[SnCl4{Et2P(CH2)2PEt2}]
Formula
M
C13H12F4N2OSn
406.94
C36H66F4P2Sn
755.52
C10H24Cl4P2Sn
466.72
Crystal system
Space group
a [Å]
tetragonal
I41/a (no. 88)
9.471(3)
9.471(3)
29.964(8)
90
triclinic
monoclinic
C2/c (no. 15)
9.708(3)
12.177(2)
16.301(5)
90
107.108(12)
90
1841.7(9)
4
2.122
928
8628 (0.049)
2100
0.722, 1.000
80, 0
1.05
–0.88 to +1.65
0.054, 0.112
0.092, 0.126
¯
P1 (no. 2)
8.251(2)
9.868(3)
11.832(4)
77.192(15)
85.601(10)
69.240(15)
878.3(4)
1
b [Å]
c [Å]
α [°]
β [°]
90
90
γ [°]
U [Å3]
Z
2687.8(15)
8
1.948
1584
9075 (0.097)
1539
0.569, 1.000
96, 1
1.04
µ [mm–1
F(000)
]
0.864
398
18769 (0.088)
4030
0.778, 1.000
196, 0
1.05
–0.69 to +0.97
0.051, 0.101
0.070, 0.108
Total no. of observations (Rint
Unique observations
Min., max. transmission
No. of parameters, restraints
Goodness-of-fit on F2
Resid electron density [e·Å–3
R1, wR2 [I Ͼ 2σ(I)][b]
R1, wR2 (all data)
]
–1.12 to +1.17
0.072, 0.180
0.128, 0.207
Compound
[SnBr4{MeC(CH2AsMe2)3}]
Formula
M
C11H27As3Br4Sn
822.42
Crystal system
Space group
a [Å]
monoclinic
P21/c (no. 14)
11.371(2)
12.839(2)
15.227(2)
90
91.731(10)
90
2221.9(6)
4
12.766
1528
22702 (0.064)
5084
b [Å]
c [Å]
α [°]
β [°]
γ [°]
U [Å3]
Z
µ [mm–1
F(000)
]
Total no. of observations (Rint
Unique observations
Min., max. transmission
No. of parameters, restraints
Goodness-of-fit on F2
0.767, 1.000
179, 0
1.03
Resid electron density [e·Å–3
R1, wR2 [I Ͼ 2σ(I)][b]
R1, wR2 (all data)
]
–0.91 to +0.84
0.026, 0.050
0.045, 0.053
2
[a] Common items: temperature = 120 K; wavelength (Mo-Kα) = 0.71073 Å; θmax. = 27.5°. [b] R1 = Σ|| Fo|–|Fc||/Σ|Fo|. wR2 = [Σw(Fo
–
2 2
4 1/2
Fc ) /ΣwFo
] .
2780
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2773–2782

SnF4 Complexes with PR3 Ligands. Comparision of Hard and Soft Donor Ligands
FULL PAPER
The white precipitate was filtered off and dried in vacuo. Yield
enediamine (0.15 g, 1.00 mmol) was added and the mixture stirred
for 12 h. The white precipitate was filtered off and dried in vacuo.
0.32 g, 80%. C10H24F4P2Sn (400.95): calcd. C 29.9, H 6.0; found
1
C 29.0, H 6.0. H NMR (300 MHz, CDCl3, 25 °C): δ = 2.13–2.07 Yield 0.14 g, 54%. C6H16F4N2Sn·1/2CH2Cl2 (277.4): calcd. C 22.1,
(m, 2 H, CH ), 1.37–1.26 (m, 6 H, Me) ppm. IR (Nujol): ν = 553
H 4.9, N 7.9; found C 22.3, H 5.1, N 8.1. 1H NMR (300 MHz,
˜
2
(m), 526 (s) υ(SnF) cm–1.
CDCl3, 25 °C): δ = 2.89 (s, 12 H, Me), 3.02 (s, 4 H, CH2) ppm. IR
(Nujol): ν = 570 (s), 547 (s) υ(SnF) cm–1.
˜
[SnF4{Cy2P(CH2)2PCy2}]: [SnF4(MeCN)2] (0.278 g, 1.00 mmol)
was suspended in CH2Cl2 (10 mL), 1,2-bis(dicyclohexylphos-
phanyl)ethane (0.444 g, 1.05 mmol) in CH2Cl2 (5 mL) was added.
This was stirred under nitrogen for 3 h. No precipitation had oc-
curred so the solution was reduced to ca. 5 mL in vacuo and then
dry hexane (5 mL) was added. Again no significant precipitate was
observed so the solvent was removed in vacuo to give a white solid.
Yield 0.51 g, 83%. C26H48F4P2Sn·1/2CH2Cl2 (826.1): calcd. C 48.2,
[SnF4(THF)2]: Was made as described.[18] 1H NMR (300 MHz,
CDCl3, 25 °C): δ = 2.1 (br., 2 H, CH2), 4.4(br., 2 H, CH2) ppm. IR
(Nujol): ν = 600 (vbr) υ(SnF), 1013 (br), 845 (m) υ(COC) cm–1.
˜
[SnCl4{MeC(CH2AsMe2)3}]:
MeC(CH2AsMe2)3
(0.384 g,
1.0 mmol) was dissolved in CH2Cl2 (10 mL) under nitrogen. To this
solution SnCl4 (0.26 g, 1.0 mmol) was added and an immediate
white precipitate formed. This was filtered off and dried in vacuo
to give a white powder. Yield 0.21 g, 33%. 1H NMR (300 MHz,
CDCl3, 25 °C): δ = 1.03 (s, 6 H, AsMe), 1.35 (s, 3 H, CMe), 1.73
1
H 7.5; found C 49.2, H 8.3. H NMR (300 MHz, CDCl3, 25 °C):
δ = 2.21–1.255 (m, CH , Cy), 5.4 (CH Cl ) ppm. IR (Nujol): ν =
˜
2
2
2
560 (s), 530 (s) υ(SnF) cm–1.
(s, 12 H, AsMe), 1.77 (s, 2 H, CH2), 2.39 (d, 2J = 12 Hz, 2 H, CH2)
2
2.54 (d, J = 12 Hz, 2 H, CH ) ppm. IR (Nujol): ν = 310 (sh), 302
˜
[SnF4{Ph2P(CH2)2PPh2}]: [SnF4(MeCN)2] (0.28 g, 1.0 mmol) was
suspended in CH2Cl2 (15 mL), 1,2-bis(diphenylphosphanyl)ethane
(0.42 g, 1.05 mmol) in CH2Cl2 (10 mL) was added and the mixture
stirred for 3 h. Most of the solvent was removed in vacuo and the
white precipitate was filtered off and dried in vacuo. Yield 0.46 g,
78%. C26H24F4P2Sn·1/2CH2Cl2 (635.6): calcd. C 50.0, H 4.0; found
2
(s), 280 (sh) υ(SnCl) cm–1.
[SnBr4{MeC(CH2AsMe2)3}]:
MeC(CH2AsMe2)3
(0.384 g,
1.0 mmol) was dissolved in CH2Cl2 (10 mL) under nitrogen. To this
solution SnBr4 (0.438 g, 1.0 mmol) was added and an immediate
yellow precipitate formed in a yellow solution. This was filtered
and the filtrate was left to stand to give yellow crystals. Yield 0.18 g,
22%. C11H27As3Br4Sn (822.4): calcd. C 16.1, H 3.3; found C 15.3,
H 3.1. 1H NMR (300 MHz, CDCl3, 25 °C): δ = 1.04 (s, 6 H,
AsMe), 1.37 (s, 3 H, CMe), 1.70 (br., 12 H, AsMe), 1.78 (br., 2 H,
CH2), 2.32 (br., 2 H, CH2) 2.55 (br., 2 H, CH2) ppm. IR (Nujol):
1
C 49.6, H 3.7. H NMR (300 MHz, CDCl3, 25 °C): δ = 7.89–7.45
(m, 5 H, Ph), 5.4 (CH2Cl2). 2.81 (br, 1 H, CH2) ppm. IR (Nujol):
ν = 566 (br) υ(SnF) cm–1.
˜
[SnCl4{Et2P(CH2)2PEt2}]: SnCl4 (0.260 g, 1.00 mmol) was dis-
solved in CH2Cl2 (15 mL), 1,2-bis(diethylphosphanyl)ethane
(0.245 mL, 1.05 mmol) was added and stirred for 2 h. Immediate
precipitation occurred, and the solid was filtered off and dried in
ν = 215 (sh), 207 (s), 199 (s) υ(SnBr) cm–1.
˜
X-ray Experimental: Crystals were grown from anhydrous CH2Cl2
solutions of the complexes by vapour diffusion of n-hexane under
dinitrogen. Brief details of the crystal data and refinement are given
in Table 10. Data collections were carried out with a Bruker-Non-
ius Kappa CCD diffractometer with graphite-monochromated Mo-
Kα radiation (λ = 0.71073 Å) and with the crystals held at 120 K
in a nitrogen gas stream. Structure solution and refinement were
routine[39–41] except as discussed below, with in all cases H atoms
added in calculated positions. The [SnF4(1,10-phenanthroline)]·
MeOH complex showed, after identifying the tin residue, two
peaks in the difference electron-density map associated with a sol-
vent molecule. The larger of the peaks positioned on a twofold axis
(proposed as an O atom) with the second peak and its symmetry
related peak being a disordered C atom of an adventitious MeOH
solvate molecule. No attempt was made to position H atoms on
this residue.
vacuo to give
a white crystalline solid. Yield 0.45 g, 96%.
C10H24Cl4P2Sn·CH2Cl2 (551.7): calcd. C 23.95, H 4.8; found C
23.5, H 5.0. 1H NMR (300 MHz, CDCl3, 25 °C): δ = 2.12–2.11 (m,
6 H, CH2), 1.39–1.21 (m, 6 H, Me), 5.4 (CH2Cl2) ppm. IR (Nujol):
ν = 318 (sh), 307 (sh), 282 (br) υ(SnCl) cm–1.
˜
[SnF4(2,2Ј-bipyridyl)]: [SnF4(MeCN)2] (0.276 g, 1.00 mmol) was
suspended in CH2Cl2 (10 mL) and a solution of 2,2Ј-bipy (0.156 g,
1.00 mmol) in CH2Cl2 (5 mL) added and the mixture refluxed for
2 h. The white precipitate was filtered off and dried in vacuo. Yield
1
0.365 g, 97%. H NMR (300 MHz, CD3NO2, 25 °C): δ = 9.41 (s,
1 H), 9.15 (s, 1 H), 8.99 (s, 1 H), 8.49 (s, 1 H) ppm. IR (Nujol): ν
˜
= 580 (s), 560, 520 (sh) υ(SnF) cm–1.
[SnF4(1,10-phenanthroline)]: Prepared similarly to the above. Yield
1
60%. H NMR (300 MHz, CDCl3, 25 °C): δ = 9.35 (m, 2 H), 9.16
(m, 2 H), 8.45 (m, 4 H) ppm. IR (Nujol): ν = 587 (s), 566 (s) υ(SnF)
˜
CCDC-299706 [for F/O(P)], -299707 [for F/P(Et2)], -299708 [for F/
O(Me)], -299709 (for F/N), -299710 [for F/P(R3)], -299711 (for Cl/
P), -299712 (for Br/As) contain the supplementary crystallographic
data for this paper (the atoms in parentheses indicate the atoms
bonded to Sn). These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
cm–1.
[SnF4{MeO(CH2)2OMe}]:
1,2-Dimethoxyethane
(0.1 mL,
1.0 mmol) was added to a solution of [SnF4(MeCN)2] (0.276 g,
1.0 mmol) in CH2Cl2 (10 mL), and the mixture stirred at reflux for
2 h. The white precipitate was filtered off and dried in vacuo. Yield
1
77%. H NMR (300 MHz, CDCl3, 200 K): δ = 3.98 (s, 3 H, Me),
4.25 (s, 2 H, CH ) ppm. IR (Nujol): ν = 609 (s), 584 (s), 540 (m)
˜
2
υ(SnF) cm–1.
Acknowledgments
[SnF4(pyridine)2]: Pyridine (0.16 g, 2.0 mmol) was added to a solu-
tion of [SnF4(MeCN)2] (0.186 g, 0.67 mmol) in CH2Cl2 (10 mL).
This was stirred at reflux under nitrogen for 2 h. The white precipi-
tate was filtered off and dried in vacuo. Yield 80%. 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 9.00 (m, 2 H), 8.2 (m, 1 H), 7.7 (m,
We thank EPSRC for support (GR/T09613/01).
[1] P. G. Harrison (Ed.), The Chemistry of Tin, Blackie, London,
1984.
[2] P. G. Harrison, in Comprehensive Coordination Chemistry (Eds.:
G. Wilkinson, R. D. Gillard, J. A. McCleverty), Pergamon
Press, Oxford, 1987, vol. 3., chap. 26.
2 H) ppm. IR (Nujol): ν = 568 (s) υ(SnF) cm–1.
˜
[SnF4{Me2N(CH2)2NMe2}]: [SnF4(MeCN)2] (0.276 g, 1.0 mmol)
was suspended in CH2Cl2 (10 mL), N,N,NЈNЈ-tetramethylethyl-
Eur. J. Inorg. Chem. 2006, 2773–2782
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
2781

M. F. Davis, M. Clarke, W. Levason, G. Reid, Michael Webster
FULL PAPER
[3]
[4]
[5]
[23] G. R. Willey, T. J. Woodman, R. J. Deeth, W. Errington, Main
Group Met. Chem. 1998, 21, 583–591.
[24] V. J. Hall, E. R. T. Tiekink, Z. Kristallogr. 1996, 211, 247–250.
[25] V. N. Zakharov, A. V. Yatsenko, A. L. Kamyshnyi, L. A. As-
lanov, Koord. Khim. 1991, 17, 789–794; (Chem. Abstr. 1991,
115, 291749v).
[26] K. A. Paseshnichenko, L. A. Aslanov, A. V. Yatsenko, S. V.
Medvedev, Koord. Khim. 1984, 10, 1279–1284; (Chem. Abstr.
1984, 101, 220263 g).
[27] W. Levason, R. Patel, G. Reid, J. Organomet. Chem. 2003, 688,
280–282.
P. G. Harrison, B. C. Lane, J. J. Zuckerman, Inorg. Chem. 1972,
11, 1537–1543.
E. W. Abel, S. K. Bhargava, K. G. Kite, V. Sik, Inorg. Chim.
Acta 1981, 49, 25–30.
a) S. J. Ruzicka, A. E. Merbach, Inorg. Chim. Acta 1976, 20,
221–229; b) S. J. Ruzicka, C. M. P. Favez, A. E. Merbach, In-
org. Chim. Acta 1977, 23, 239–247.
S. E. Dann, A. R. J. Genge, W. Levason, G. Reid, J. Chem.
Soc., Dalton Trans. 1996, 4471–4478.
S. E. Dann, A. R. J. Genge, W. Levason, G. Reid, J. Chem.
Soc., Dalton Trans. 1997, 2207–2213.
A. R. J. Genge, W. Levason, G. Reid, J. Chem. Soc., Dalton
Trans. 1997, 4549–4554.
A. R. J. Genge, W. Levason, G. Reid, Inorg. Chim. Acta 1999,
288, 142–149.
W. Levason, M. L. Matthews, R. Patel, G. Reid, M. Webster,
New J. Chem. 2003, 27, 1784–1788.
[6]
[7]
[8]
[9]
[10]
[28] F. Kunnkel, K. Dehnicke, Z. Naturforsch., Teil B 1995, 50, 848–
850.
[29] a) L. F. Warren, M. A. Bennett, Inorg. Chem. 1976, 15, 3126–
3140; b) W. Levason, Comments Inorg. Chem. 1990, 9, 331–361.
[30] M. F. Mahon, N. L. Moldovan, K. C. Molloy, A. Muresan, I.
Silaghi-Dumitrescu, L. Silaghi-Dumitrescu, Dalton Trans.
2004, 4017–4021.
[31] P. A. W. Dean, D. F. Evans, J. Chem. Soc. A 1968, 1154–1166.
[32] K. B. Dillon, A. Marshall, J. Chem. Soc., Dalton Trans. 1984,
1245–1247.
[11]
[12]
A. A. Woolf, J. Inorg. Nucl. Chem. 1956, 3, 285–288.
J. P. Clark, V. M. Langford, C. J. Wilkins, J. Chem. Soc. A 1967,
792–794.
[13] C. E. Michelson, D. S. Dyer, R. O. Ragsdale, J. Inorg. Nucl.
Chem. 1970, 32, 833–838.
[14] C. J. Wilkins, H. M. Haendler, J. Chem. Soc. 1965, 3174–3178.
[15] S. H. Hunter, V. M. Langford, G. A. Rodley, C. J. Wilkins, J.
Chem. Soc. A 1968, 305–308.
[33] J. Mason (Ed.), Multinuclear NMR, Plenum, NY, 1987.
[34] M. Sigl, A. Schier, H. Schmidbauer, Eur. J. Inorg. Chem. 1998,
203–210.
[35] R. D. Feltham, R. S. Nyholm, A. Kasenally, J. Organomet.
Chem. 1967, 7, 285–288.
[16] A. D. Adley, P. H. Bird, A. R. Fraser, M. Onyszchuk, Inorg.
Chem. 1972, 11, 1402–1409.
[17] M. Bork, R. Hoppe, Z. Anorg. Allg. Chem. 1996, 622, 1557–
1563.
[18] a) D. Tudela, F. Rey, Z. Anorg. Allg. Chem. 1989, 575, 202–
208; b) D. Tudela, F. Patron, Inorg. Synth. 1997, 31, 92–93.
[19] M. F. Davis, W. Levason, G. Reid, M. Webster, Polyhedron
2006, 25, 930–936.
[20] G. G. Mather, G. M. McLaughlin, A. Pidcock, J. Chem. Soc.,
Dalton Trans. 1973, 1823–1827.
[21] D. Dakternieks, H. Zhu, E. R. T. Tiekink, Main Group Met.
Chem. 1994, 17, 519–535.
[22] N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, R. G. Pritch-
ard, J. Chem. Soc., Chem. Commun. 1994, 695–696.
[36] H. C. E. McFarlane, W. McFarlane, Polyhedron 1983, 2, 303–
304.
[37] A. M. Aguiar, J. Beisler, J. Org. Chem. 1964, 29, 1660–1662.
[38] E. P. Kyba, S. T. Liu, R. L. Harris, Organometallics 1983, 2,
1877–1879.
[39] G. M. Sheldrick, SHELXS-97, Program for crystal structure
solution, University of Göttingen, Germany, 1997.
[40] G. M. Sheldrick, SHELXL-97, Program for crystal structure re-
finement, University of Göttingen, Germany, 1997.
[41] G. M. Sheldrick, SADABS, Bruker-Nonius area detector scaling
and absorption correction (V2.10), University of Göttingen,
Germany, 2003.
Received: March 6, 2006
Published Online: May 2, 2006
2782
www.eurjic.org
© 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2006, 2773–2782