Reactions of TaF5 with activated arenes. Synthesis of [4-(OH)-3-(OCH3)C6H3CH(OH)][4-(OH)-3-(OCH 3)C6H3CHO][TaF6], a rare example of protonated aldehyde

Article abstract of DOI:10.1016/j.poly.2013.12.015

The rare example of protonated aldehyde salt [4-(OH)-3-(OCH ₃)C₆H₃CH(OH)][4-(OH)-3-(OCH₃)C ₆H₃CHO][TaF₆], 1, was isolated in the solid state by the reaction of 4-hydroxy-3-methoxybenzaldehyde (vanillin) with TaF₅ in dichloromethane. The product 1 was characterized by X-ray diffraction and IR spectroscopy. The 1:1 reaction of TaF₅ with N,N-dimethylaniline in CH₂Cl₂ cleanly afforded [TaF ₄(NMe₂C₆H₅)₂][TaF ₆], 2, which was identified by NMR spectroscopy. Attempts of crystallization of 2 resulted in the isolation of the ammonium salt [NHMe ₂C₆H₅][TaF₆], 3.

Full text of DOI:10.1016/j.poly.2013.12.015

Polyhedron 70 (2014) 6–10
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Reactions of TaF5 with activated arenes. Synthesis
of [4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6H3CHO][TaF6],
a rare example of protonated aldehyde
b
Mohammad Hayatifar a, Fabio Marchetti a, Guido Pampaloni a, , Stefano Zacchini
⇑
a Università di Pisa, Dipartimento di Chimica e Chimica Industriale, Via Risorgimento 35, I-56126 Pisa, Italy
b Dipartimento di Chimica Fisica e Inorganica, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
a r t i c l e i n f o
a b s t r a c t
Article history:
The rare example of protonated aldehyde salt [4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6H3-
CHO][TaF6], 1, was isolated in the solid state by the reaction of 4-hydroxy-3-methoxybenzaldehyde
(vanillin) with TaF5 in dichloromethane. The product 1 was characterized by X-ray diffraction and IR
spectroscopy. The 1:1 reaction of TaF5 with N,N-dimethylaniline in CH2Cl2 cleanly afforded [TaF4(NMe2-
C6H5)2][TaF6], 2, which was identified by NMR spectroscopy. Attempts of crystallization of 2 resulted in
the isolation of the ammonium salt [NHMe2C6H5][TaF6], 3.
Received 11 November 2013
Accepted 13 December 2013
Available online 21 December 2013
Keywords:
Tantalum pentafluoride
Crystal structure
Protonated aldehydes
Vanillin
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
[11]. Radical salts lacking of electron-donor substituents have been
produced in low yields by the same method.
The isolation of uncommon cations has been possible in view of
the availability of large, non coordinating and weakly-basic anions
such as carboranes or fluorinated tetraphenylborates [1].
Niobium(V) and tantalum(V) haloanions (or mixed alkoxo-
haloanions) have revealed to be effective for the stabilization of
reactive cationic species such as O-protonated ketones [2], O-
methylated ketones [3], diglyme [4], thioethers [5], indanyl- and
anthryl cations [6].
3MF5 þ Arene ! ½Areneꢀ½M2F11ꢀ þ MF4
ð1Þ
Arene ¼ alkyl-; alkoxy-; fluoro- and nitro-substituted benzenes
In general, adventitious hydrolysis [4,5], activation of the organ-
ic substrate [8] and the solvent [5] are the possible proton sources
for those reactions involving niobium and tantalum pentafluorides
and leading to the protonation of the organic reactant.
The reactions of MF5 with arenes bearing electron-donor sub-
stituents proceed through the initial coordination of the organic
moiety to the metal fluoride [7], followed by activation. Thus are-
nium salts of formula [2,4-(OMe)2C6H5][M2F11] (M = Nb, Ta) have
been isolated in the solid state at room temperature from MF5/
1,3-dimethoxybenzene: they are robust species which resist ther-
mal treatment in CHCl3 [8]. Previously reported dialkoxybenzeni-
um ions were detected at room temperature in concentrated
H2SO4 [9] or, at low temperature, by using conventional superaci-
dic systems (e.g. SbF5/HF) [10].
Herein we report an extension of the investigation on the reac-
tivity of TaF5 [12]1 with activated arenes. To the purpose, a function-
alized aromatic aldehyde, [4-(OH)-3-(OCH3)C6H3CHO, vanillin], and
an aromatic amine, N,N-dimethylaniline, have been considered.
The reactions have afforded the rare example of crystallographi-
cally-characterized protonated aldehyde [4-(OH)-3-(OCH3)C6H3CH
(@OAH)][4-(OH)-3-(OCH3)C6H3CHO][TaF6], and the ionic derivative
[TaF4(NMe2C6H5)2][TaF6], respectively.
2. Results and discussion
Furthermore, deeply-coloured solutions of arene radical cation
salts have been obtained by treatment of the appropriate monocy-
clic aromatic compound with MF5 (M = Nb, Ta), according to Eq. (1)
The reaction of a dichloromethane suspension of TaF5 with van-
illin in molar ratio 1:1 afforded
a complicated mixture of
1
⇑
Corresponding author. Tel.: +39 0502219219; fax: +39 0502219246.
E-mail addresses: fabmar@dcci.unipi.it (F. Marchetti), pampa@dcci.unipi.it
(G. Pampaloni).
The pentafluoride of tantalum(V) has tetranuclear structure in the solid state [A.F.
Wells, Structural Inorganic Chemistry, 5th ed., Clarendon Press, Oxford, 1993 and Ref.
12]. For sake of simplicity, the empirical formula TaF5 will be used throughout the
present paper.
URL: http://www.dcci.unipi.it/~pampa/ (G. Pampaloni).
0277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.12.015

M. Hayatifar et al. / Polyhedron 70 (2014) 6–10
7
HO
MeO
CHO
MeO
HO
OMe
OH
O
[TaF6]
TaF5
CH
H
CH
CH Cl , r.t.
2
2
O
1
Scheme 1. Reaction of TaF5 with vanillin.
unidentified products, according to NMR spectroscopy. The crystal-
line salt [4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6H3
CHO][TaF6], 1, was isolated in moderate amount by crystallization
from the reaction mixture (Scheme 1); the use of higher vanillin/
TaF5 molar ratios resulted in yield decreasing.
Once isolated in the crystalline form, 1 is nearly insoluble in
chlorinated solvents, while it undergoes quick degradation in more
polar solvents (e.g. acetonitrile): these facts prevented a clear NMR
characterization of 1. The IR spectrum of 1 features a broad band
centered at 3376 cmꢁ1, due to overlap of stretching vibrations of
the covalent OH bond and of the Oꢂ ꢂ ꢂH–O hydrogen bonding inter-
action. Vanillin, characterized by a different hydrogen bonding net-
work, involving the OH group as proton-donor and the aldehydic
oxygen as proton-acceptor [13], shows a broad absorption at lower
wavenumbers (3212 cmꢁ1) [14]. The most salient feature of the IR
spectrum of 1 is the absence of a strong absorption in the C@O car-
bonyl stretching region (a weak signal is present at 1622 cmꢁ1). A
similar situation was reported for protonated 1-pyrene carboxal-
dehyde and 9-antraldehyde [15]. This fact may be the consequence
of elongation of the C@O aldehydic bond [1.26(2) and 1.22(2) Å]
with respect to free vanillin [1.202–1.206 Å], due to the formation
of the hydrogen-bonded dimer (vide infra).
Fig. 1. ORTEP representation of the content of the asymmetric unit of the unit cell of
{[4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6H3CHO]}[TaF6], 1, with key
atoms labeled. Displacement ellipsoids are at the 50% probability level.
EPR analysis on the 1:1 reaction mixture TaF5/vanillin was car-
ried out after addition of acetonitrile, however no tantalum(IV)
derivatives were detected2. This outcome suggests that radical spe-
cies do not form in the course of the reaction [11], therefore the pro-
tonation of the organic compound cannot proceed via a redox
process followed by H transfer (redox reactions were recognized
for a series of TaF5/alkoxyarene systems) [11].
hydrogen bond parameters are given in Table 2. The O(6)ꢂ ꢂ ꢂO(3)
distance [2.48(2) Å] is typical of a strong H-bond, as previously
found in the very few other examples of protonated aldehydes re-
ported in the literature [15]. As a consequence of the protonation
of O(6) and formation of the strong O(6)ꢁH(6)ꢂ ꢂ ꢂO(3) hydrogen
bond, the two C@O aldehyde units [C(8)–O(3) 1.26(2) Å; C(18)–
O(6) 1.22(2) Å] are sensibly elongated compared to free vanillin
[1.202–1.206 Å] [13]. In addition, the hydroxyl O(1)ꢁH(1) group
of the non-protonated vanillin is involved as donor in a weaker
hydrogen bond towards the hydroxyl O(4) atom of a second
protonated vanillin, resulting in an infinite chain of alternate pro-
tonated and non-protonated molecules. An intramolecular
Instead, the formation of 1 is presumably the result of H+ cap-
ture from the reaction medium, assisted by the high-stability of
the [TaF6]ꢁ anion, which can be generated upon asymmetric dis-
ruption of the tetranuclear frame of TaF5 [12,16,17]. In principle,
uncontrolled traces of water [5], the solvent and the reactant itself
constitute the possible proton sources. The latter probably plays a
significant role, in view of the favourable acidity (the pKa value of
vanillin in water is 7.496) [18]. Attempts aimed to identify the
side-products of the reaction did not provide conclusive
information.
After several attempts, X-ray quality crystals of 1 were obtained
by layering with heptane a dichloromethane solution of 1, thus
allowing a full characterization. An ORTEP representation of the con-
tent of the asymmetric unit of the unit cell of 1 is reported in Fig. 1,
whereas the main bonding parameters are summarized in Table 1.
The salt is composed by an octahedral [TaF6]ꢁ anion and a H-
bonded {[4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6-
H3CHO]}+ dimeric cation consisting of one protonated and one
non protonated vanillin molecules. Protonation has occurred at
the aldehyde O(6)-atom and the dimer is formed because of a
strong H-bond involving O(6) and H(6) as donor and the free alde-
hydic O(3) atom of the non-protonated vanillin as acceptor. A rep-
resentation of the cationic dimer is reported in Fig. 2, whereas its
O(1)ꢁH(1)ꢂ ꢂ ꢂO(2) hydrogen bond is present as well as
a
O(4)ꢁH(4)ꢂ ꢂ ꢂF(5) contact, the latter involving the O(4)ꢁH(4) hy-
droxyl group of the free vanillin as donor and the [TaF6]ꢁ anion
as acceptor (Table 2). The presence of several strong and weak
OꢁHꢂ ꢂ ꢂO and OꢁHꢂ ꢂ ꢂF hydrogen bonds results in the ordered 3-D
packing of the salt as represented in Fig. S1 (Supporting informa-
tion). It must be noticed that, in crystalline vanillin, a hydrogen
bond network is present, involving the hydroxyl group as donor
and the aldehydic oxygen as acceptor [13] (Fig. S2).
We extended the present study to the reactivity of tantalum
pentafluoride with arene molecules containing a nitrogen-based
substituent. The clearest result was obtained by the 1:1 reaction
of TaF5 with N,N-dimethyalaniline, which was carried out in
dichloromethane. This reaction selectively afforded a green solu-
tion of the well-soluble salt [TaF4(NMe2C6H5)2][TaF6], 2. This com-
pound has been characterized by NMR on a green CD2Cl2 reaction
mixture. The N-bound methyls resonate as single peaks in both 1H
and 13C NMR spectra (d = 3.28 and 48.0 ppm, respectively). Such
resonances are significantly low-field shifted compared to what
2
A similar procedure allowed us to identify stable M(IV) species in the reactions of
arenes with MF5 (M = Nb, Ta) [11a,b].

8
M. Hayatifar et al. / Polyhedron 70 (2014) 6–10
Table 1
Main bond distances (Å) and angles (°) of 1.
{[4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-(OCH3)C6H3CHO)]}+ cation
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(1)–C(6)
C(4)–C(8)
C(1)–O(1)
C(6)–O(2)
C(8)–O(3)
C(7)–O(2)
O(3)–C(8)–C(4)
1.41(3)
1.36(3)
1.41(3)
1.46(3)
1.30(3)
1.42(3)
1.39(3)
1.34(2)
1.38(2)
1.26(2)
1.50(2)
119.9(19)
C(11)–C(12)
C(12)–C(13)
C(13)–C(14)
C(14)–C(15)
C(15)–C(16)
C(11)–C(16)
C(14)–C(18)
C(11)–O(4)
C(16)–O(5)
C(18)–O(6)
C(17)–O(5)
O(6)–C(18)–C(14)
1.35(3)
1.39(3)
1.38(3)
1.40(3)
1.34(3)
1.46(3)
1.47(3)
1.34(3)
1.37(2)
1.22(2)
1.42(2)
124(2)
[TaF6]ꢁ anion
Ta(1)–F(1)
Ta(1)–F(3)
1.886(18)
1.857(18)
1.85(2)
Ta(1)–F(2)
Ta(1)–F(4)
Ta(1)–F(6)
1.81(2)
1.846(19)
1.90(2)
Ta(1)–F(5)
F(5)–Ta(1)–F(3)
F(4)–Ta(1)–F(6)
170.7(9)
177.6(10)
F(2)–Ta(1)–F(1)
178.4(9)
Sum angles at C(1): 360(3)°; sum angles at benzene ring; 720(4)°.
3194 cmꢁ1 in the solid state IR spectrum (N–H stretching vibra-
tion). The resonance at 40.0 ppm in the 19F-spectrum is diagnostic
for the presence of the [TaF6]ꢁ anion.
The formation of 3 appears to be the consequence of H+ capture
from the reaction medium, presumably made possible by the pres-
ence of adventitious water, Scheme 2.
3. Conclusions
In this paper, we have described the synthesis and the struc-
tural properties of a rare example of protonated-aldehyde salt, as
obtained from the reaction of TaF5 with vanillin. The product
consists of an octahedral [TaF6]ꢁ anion and a H-bonded {[4-(OH)-
Fig. 2. The H-bonded dimeric {[4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-
(OCH3)C6H3CHO]}+ cation present in 1. The dashed line represents the O(6)–
H(6)ꢂ ꢂ ꢂO(3) hydrogen bond.
3-(OCH3)C6H3CH(=O–H)][4-(OH)-3-(OCH3)C6H3CHO)]}+
dimeric
cation, formally made of one vanillin molecule linked to one alde-
hyde-O-atom-protonated vanillin. The combination of the acidity
of vanillin [18] with the high stability of the [TaF6]ꢁ ion may be
the driving force for the formation of such product.
On the other hand, the reaction of N,N-dimethylaniline with
TaF5 selectively produces the ionic derivative [TaF4(NMe2C6H5)2]
[TaF6]. The solid state isolation of the relevant ammonium salt
has been presumably made possible by the action of adventitious
water.
Table 2
Hydrogen bonds for 1 [Å and °].
D–Hꢂ ꢂ ꢂA
d(D–H)
d(Hꢂ ꢂ ꢂA)
d(Dꢂ ꢂ ꢂA)
<(DHA)
O(1)–H(1)ꢂ ꢂ ꢂO(4)#1
O(1)–H(1)ꢂ ꢂ ꢂO(2)
0.84
0.84
0.84
0.84
2.04
2.15
2.07
1.64
2.754(15)
2.610(18)
2.91(3)
143.2
114.2
176.1
171.8
O(4)–H(4)ꢂ ꢂ ꢂF(5)#2
O(6)–H(6)ꢂ ꢂ ꢂO(3)#1
2.48(2)
Symmetry transformations used to generate equivalent atoms: #1 ꢁx + 3/2,yꢁ1/2,z
#2 ꢁx + 3/2,y + 1/2,z.
4. Experimental
4.1. General procedures
is seen in uncoordinated N,N-dimethylaniline (d = 2.89 and 40.50,
respectively) [19], thus suggesting the engagement of the amino-
group in coordination to the metal centre. The 19F NMR spectrum
consists of a resonance at 40.3 ppm, accounting for the [TaF6]ꢁ an-
ion [16,17,20] and indicating the occurrence of asymmetric cleav-
age of the tetranuclear Ta4F20 frame upon addition of the organic
reactant [16,17]. As often occurs, the resonance due to the
[TaF4]+ moiety is not observed in the 19F spectrum of compound
2 [20].
All of the attempts to obtain X-ray quality crystals of 2 failed.
Nonetheless one of these attempts led to the low-yield isolation
of the ammonium salt [NHMe2C6H5][TaF6], 3. The 1H NMR of this
latter clearly displays a broad resonance ascribable to the nitro-
gen-bonded proton, at d = 9.03 ppm. The presence of the NH moi-
ety has been confirmed by a medium absorption occurring at
All manipulations of air and/or moisture sensitive compounds
were performed under atmosphere of pre-purified argon using
standard Schlenk techniques. The reaction vessels were oven dried
at 150 °C prior to use, evacuated (10ꢁ2 mmHg) and then filled with
nitrogen. TaF5 was purchased from Apollo Sci. (99% purity), sub-
limed prior to use and stored in sealed glass tubes under argon
atmosphere. The organic reactants were commercial products (Sig-
ma–Aldrich) stored under argon atmosphere as received. Solvents
(Sigma–Aldrich) were distilled before use from appropriate drying
agents. Infrared spectra were recorded at 298 K on FT IR Spectrum
One Perkin Elmer Spectrometer, equipped with UATR sampling
accessory. NMR spectra were recorded at 293 K on Bruker Avance
DRX400 instrument equipped with BBFO broadband probe. The
chemical shifts for 1H and 13C spectra were referenced to the
non-deuterated aliquot of the solvent, while the chemical shifts

M. Hayatifar et al. / Polyhedron 70 (2014) 6–10
9
F
F
F
NMe2
Me2
H2O
NHMe2 [TaF6]
N
N
TaF5
[TaF6]
CH2Cl2, r.t.
Me2
F
3
2
Scheme 2. Reaction of TaF5 with N,N-dimethylaniline.
for 19F spectra were referenced to CFCl3. 1H and 13C NMR
assignments were assisted by HSQC and HMBC experiments [21].
Carbon, hydrogen and nitrogen analyses were performed on Carlo
Erba mod. 1106 instrument. The fluoride content was determined
by fluoride ion selective electrode, after boiling the sample in alka-
line solution. Tantalum was analyzed as Ta2O5 obtained by high
temperature treatment of the solid sample with HNO3 solution,
followed by calcination in a platinum crucible.
4.4. X-ray crystallographic study
Crystal data and collection details for 1 are listed in Table 3. The
diffraction experiments were carried out on Bruker APEX II diffrac-
tometer equipped with CCD detector and using Mo K
a radiation.
Data were corrected for Lorentz polarization and absorption effects
(empirical absorption correction SADABS) [22]. The structures were
solved by direct methods and refined by full-matrix least-squares
based on all data using F2 [22]. All non-hydrogen atoms were re-
fined with anisotropic displacement parameters. H-atoms were
placed in calculated positions and treated isotropically using the
1.2 fold Uiso value of the parent atom except methyl protons, which
were assigned the 1.5 fold Uiso value of the parent C-atom. The O-
bonded H-atoms were initially located in the Fourier map but,
then, they were refined with a riding model. Similar U restraints
(s.u. 0.01) were applied to the C, O and F atoms. The F-atoms were
restrained to an isotropic like behaviour (ISOR line in SHELXL; s.u.
0.01).
4.2. Preparation of [4-(OH)-3-(OCH3)C6H3CH(@OAH)][4-(OH)-3-
(OCH3)C6H3CHO] [TaF6] 1
TaF5 (0.129 g, 0.467 mmol) was allowed to react with vanillin
(0.072 g, 0.470 mmol) in CH2Cl2 (15 mL). The mixture was stirred
for 15 h at room temperature, and the colour progressively chan-
ged from colourless to green. The final mixture was filtered in or-
der to remove some dark-green precipitate; the filtrated green
solution was layered with heptane and stored at room temperature
for 72 h. Hence a crop of green crystals of 1 were collected. Yield:
0.101 g, 36% (based on Ta). Anal. Calc. for C16H17F6O6Ta: C, 32.01; H,
2.85; F, 18.99; Ta, 30.14. Found: C, 31.75; H, 2.70; F, 18.12; Ta,
Appendix A. Supplementary data
28.95%. IR (solid state):
1574vs-br (C@O), 1511vs-sh, 1506vs, 1467m-s, 1434m, 1410w,
m
= 3376m-br (OꢁH), 2961w, 2921w,
CCDC 949676 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: +44 1223 336 033; or e-mail: deposit@ccdc.cam.ac.uk.
Fig. S1 reports a view of the crystal packing of 1 along the crystal-
lographic (A) a-axis, (B) b-axis and (C) c-axis. Fig. S2 represents the
hydrogen-bond linking in solid vanillin. Supplementary data asso-
ciated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.poly.2013.12.015.
1301s, 1272s, 1169s, 1124m, 1024m, 866w-m, 824w, 783w,
734w-m cmꢁ1
.
The reaction of TaF5 (0.30 mmol) with vanillin (0.30 mmol), car-
ried out in CD2Cl2 (1.0 mL), afforded a green solution which was
analyzed by NMR.
detected.
A mixture of unidentified products was
4.3. Isolation of [NHMe2C6H5][TaF6], 3, and NMR characterization of
[TaF4(NMe2C6H5)2][TaF6] 2
Table 3
A suspension of TaF5 (0.205 g, 0.743 mmol) in dichloromethane
(15 mL) was treated with N,N-dimethylaniline (0.095 mL,
0.750 mmol), and the resulting mixture was stirred for 18 h at
room temperature. The final product 3 was obtained as colourless
crystalline material upon crystallization from the green reaction
solution layered with heptane, at ꢁ30 °C. Yield: 0.041 g, 13% (based
on Ta). Anal. Calc. for C8H12F6NTa: C, 23.03; H, 2.90; N, 3.36; F,
27.33; Ta, 43.38. Found: C, 23.12; H, 2.74; N, 3.28; F, 26.86; Ta,
Crystal data and details of the structure refinement for 1.
Formula
C16H17F6O6Ta
Fw
T (K)
k (Å)
Crystal system
Space group
a (Å)
b (Å)
600.25
100(2)
0.71073
orthorhombic
Pbca
13.284(6)
16.258(7)
17.939(8)
3874(3)
43.20%. IR (solid state):
2891w, 1600w-m, 1489s, 1468m-s, 1416m, 1361w-m, 1131s,
1082m, 1048m, 1025m, 985s, 898vs, 771s, 761vs, 696vs cmꢁ1 1H
m
= 3194m (NꢁH), 3068w, 2977w,
c (Å)
Cell volume (Å3)
.
Z
8
NMR (CD2Cl2): d = 9.03 (br, 1 H, NH), 7.67–7.55 (m, 5 H, Ph),
3.43, 3.41 (s, 6 H, Me) ppm. 13C NMR (CD2Cl2): d = 141.6 (ipso-
Ph), 131.2, 131.1, 119.9 (Ph), 48.2 (Me) ppm. 19F NMR (CD2Cl2):
d = 40.0 ([TaF6]ꢁ) ppm.
The addition of N,N-dimethylaniline (0.080 mL, 0.632 mmol) to
TaF5 (0.150 g, 0.634 mmol) in CD2Cl2 (0.60 mL) quickly afforded a
green solution which was analyzed by NMR spectroscopy, thus
allowing the characterization of 2. 1H NMR (CD2Cl2): d = 7.50,
7.42, 7.31 (m, 5 H, Ph), 3.28 (s, 6 H, Me) ppm. 13C NMR (CD2Cl2):
d = 148.1 (ipso-Ph), 129.5, 125.8, 119.1 (Ph), 48.0 (Me) ppm. 19F
NMR (CD2Cl2): d = 40.3 ([TaF6]ꢁ) ppm.
Dcalc (g cmꢁ3
)
2.058
5.761
2304
0.18 ꢃ 0.16 ꢃ 0.10
2.27–25.03
26350
3409 [Rint = 0.1391]
3409/170/262
1.173
l
(mmꢁ1
F(000)
)
Crystal size, mm
h Limits (°)
Reflections collected
Independent reflections
Data/restraints /parameters
Goodness of fit (GOF) on F2
R1 (I > 2
r
(I))
0.1004
0.2535
2.749/ꢁ3.098
wR2 (all data)
Largest difference peak and hole (e Åꢁ3
)

10
M. Hayatifar et al. / Polyhedron 70 (2014) 6–10
(b) F. Marchetti, G. Pampaloni, C. Pinzino, J. Organomet. Chem. 696 (2011)
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