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Solvate-free bis­(triphenylphosphine)iminium chloride

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Acta Crystallographica Section E: Crystallographic Communications
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The title compound, C36H30NP2⁺·Cl⁻, crystallized in the solvate-free form from a CH3CN/OEt2 solution. The chloride anion and the N atom of the [(Ph3P)2N]⁺ cation are located on a twofold axis, yielding overall symmetry 2 for the cation. The central P—N—P angle [133.0 (3)°] is at the low end of the range of observed P—N—P angles.
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Solvate-free bis(triphenylphosphine)-
iminium chloride
Carsten Knapp* and Rabiya Uzun
Institut fu
¨r Anorganische und Analytische Chemie, Albert-Ludwigs-Universita
¨t
Freiburg, Albertstrasse 21, 79104 Freiburg i. Br., Germany
Correspondence e-mail: carsten.knapp@ac.uni-freiburg.de
Received 25 October 2010; accepted 9 November 2010
Key indicators: single-crystal X-ray study; T= 123 K; mean (C–C) = 0.004 A
˚;
Rfactor = 0.049; wR factor = 0.135; data-to-parameter ratio = 13.9.
The title compound, C
36
H
30
NP
2+
Cl
, crystallized in the
solvate-free form from a CH
3
CN/OEt
2
solution. The chloride
anion and the N atom of the [(Ph
3
P)
2
N]
+
cation are located on
a twofold axis, yielding overall symmetry 2 for the cation. The
central P—N—P angle [133.0 (3)] is at the low end of the
range of observed P—N—P angles.
Related literature
Several bis(triphenylphosphine)iminium chloride structures
containing solvate molecules have been determined. For
[(Ph
3
P)
2
N]ClB(OH)
3
, see: Andrews et al. (1983); for
[(Ph
3
P)
2
N]ClCH
3
C
6
H
5
, see: Weller et al. (1993); for
[(Ph
3
P)
2
N]ClCH
2
Cl
2
, see: Carroll et al. (1996); for [(Ph
3
P)
2
N]-
ClCH
2
Cl
2
H
2
O, see: de Arellano (1997). Other bis(triphenyl-
phosphine)iminium halide structures have been determined:
for [(Ph
3
P)
2
N]BrCH
3
CN, see: Knapp & Uzun (2010); for
[(Ph
3
P)
2
N]I, see: Beckett et al. (2010). For a discussion of the
[(Ph
3
P)
2
N]
+
cation, see: Lewis & Dance (2000). For a
description of the Cambridge Structural Database, see: Allen
(2002). For the synthesis, see: Ruff & Schlientz (1974).
Experimental
Crystal data
C
36
H
30
NP
2+
Cl
M
r
= 574.00
Monoclinic, C2=c
a= 15.094 (3) A
˚
b= 10.499 (2) A
˚
c= 18.615 (4) A
˚
= 99.06 (3)
V= 2913.0 (10) A
˚
3
Z=4
Mo Kradiation
= 0.27 mm
1
T= 123 K
0.30 0.23 0.23 mm
Data collection
Rigaku R-AXIS Spider
diffractometer
Absorption correction: multi-scan
(ABSCOR; Higashi, 2001)
T
min
= 0.924, T
max
= 0.941
7362 measured reflections
2551 independent reflections
2296 reflections with I>2(I)
R
int
= 0.043
Refinement
R[F
2
>2(F
2
)] = 0.049
wR(F
2
) = 0.135
S= 1.24
2551 reflections
183 parameters
H-atom parameters constrained
max
= 0.41 e A
˚
3
min
=0.42 e A
˚
3
Table 1
Selected geometric parameters (A
˚,).
P1—N1 1.5984 (18)
P1—C7 1.795 (3)
P1—C1 1.802 (3)
P1—C13 1.811 (3)
P1—N1—P1
i
133.0 (3)
Symmetry code: (i) xþ1;y;zþ3
2.
Data collection: CrystalClear (Rigaku, 2007); cell refinement:
CrystalClear; data reduction: CrystalClear; program(s) used to solve
structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine
structure: SHELXL97 (Sheldrick, 2008); molecular graphics:
DIAMOND (Brandenburg & Putz, 2010); software used to prepare
material for publication: SHELXL97.
Financial support by the Deutsche Forschungsgemeinschaft
(DFG) and the Universita
¨t Freiburg is gratefully acknowl-
edged.
Supplementary data and figures for this paper are available from the
IUCr electronic archives (Reference: FI2099).
References
Allen, F. H. (2002). Acta Cryst. B58, 380–388.
Andrews, S. J., Robb, D. A. & Welch, A. J. (1983). Acta Cryst. C39, 880–882.
Arellano, M. C. R. de (1997). Private communication (refcode: RAVBUL).
CCDC, Cambridge, England.
Beckett, M. A., Horton, P. N., Hursthouse, M. B. & Timmis, J. L. (2010). Acta
Cryst. E66, o319.
Brandenburg, K. & Putz, H. (2010). DIAMOND. Crystal Impact GbR, Bonn,
Germany.
Carroll, K. M., Rheingold, A. L. & Allen, M. B. (1996). Private communication
(refcode: NAVMEM ). CCDC, Cambridge, England.
Higashi, T. (2001). ABSCOR. Rigaku Corporation, Tokyo, Japan.
Knapp, C. & Uzun, R. (2010). Acta Cryst. E66, o3186.
Lewis, G. R. & Dance, I. (2000). J. Chem. Soc. Dalton Trans. pp. 299–306.
Rigaku (2007). CrystalClear. Rigaku Corporation, Tokyo, Japan.
Ruff, J. K. & Schlientz, W. J. (1974). Inorg. Synth. 15, 84–87.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Weller, F., Nussha
¨r, D. & Dehnicke, K. (1993). Z. Kristallogr. 208, 322–325.
organic compounds
Acta Cryst. (2010). E66, o3185 doi:10.1107/S1600536810046325 Knapp and Uzun o3185
Acta Crystallographica Section E
Structure Reports
Online
ISSN 1600-5368
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Acta Cryst. (2010). E66, o3185
supporting information
Acta Cryst. (2010). E66, o3185 [https://doi.org/10.1107/S1600536810046325]
Solvate-free bis(triphenylphosphine)iminium chloride
Carsten Knapp and Rabiya Uzun
S1. Comment
The title compound [(Ph3P)2N]Cl ([PNP]Cl) is a very important starting material and numerous crystal structures
containing the [(Ph3P)2N]+ cation are known. The Cambridge Structural Database (Allen, 2002) currently contains more
than 1200 structures containing the [(Ph3P)2N]+ cation. Usually this cation is partnered by a bulky cation, while crystal
structures containing small anions and especially halides are rare. Very recently, the crystal structures of solvate-free
[(Ph3P)2N]I (Beckett et al., 2010) and [(Ph3P)2N]Br.CH3CN (Knapp et al., 2010) were published.
Several crystal structures of [(Ph3P)2N]Cl containing solvate molecules have been determined, e.g. [(Ph3P)2N]Cl.B(OH)3
(Andrews et al. (1983)), [(Ph3P)2N]Cl.CH3C6H5, (Weller et al. (1993)), [(Ph3P)2N]Cl.CH2Cl2 (Carroll et al. (1996)),
[(Ph3P)2N]Cl.CH2Cl2.H2O (de Arellano (1997)). Surprisingly, the crystal structure of the parent compound [(Ph3P)2N]Cl
was still unknown.
[(Ph3P)2N]Cl has been synthesized according to a published method (Ruff et al., 1974) and solvate-free single crystals
suitable for X-ray diffraction were obtained by layering a CH3CN solution with diethyl ether. The chlorine anion and the
[(Ph3P)2N]+ cation are located on a 2 axis, yielding overall symmetry 2 of the cation. The central P—N—P angle [133.1
(3)°] is on the low end of the range of observed P—N—P angles. The P-N (1.597 (2) Å) and P-C distances (179.3 (4)–
180.8 (4) Å) are in the expected range.
S2. Experimental
[(Ph3P)2N]Cl has been synthesized according to a published method (Ruff et al., 1974). Single crystals suitable for X-ray
diffraction were obtained by layering a CH3CN solution with diethyl ether.
S3. Refinement
The hydrogen atoms were positioned geometrically and refined using a riding model. The same Uiso value was used for all
H atoms, which refined to 0.031 (3) Å2.
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Acta Cryst. (2010). E66, o3185
Figure 1
View of the ionic unit of [(Ph3P)2N]Cl. Displacement ellipsoids are shown at the 50% probability level and hydrogen
atoms are drawn with arbitrary radii. Symmetry code: (i) 1-x, y, 1.5-z.
Figure 2
View of the surrounding of the chloride anion.
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Acta Cryst. (2010). E66, o3185
Bis(triphenylphosphanylidene)iminium chloride
Crystal data
C36H30NP2+·Cl
Mr = 574.00
Monoclinic, C2/c
Hall symbol: -C 2yc
a = 15.094 (3) Å
b = 10.499 (2) Å
c = 18.615 (4) Å
β = 99.06 (3)°
V = 2913.0 (10) Å3
Z = 4
F(000) = 1200
Dx = 1.309 Mg m−3
Mo radiation, λ = 0.71073 Å
Cell parameters from 1435 reflections
θ = 2.2–27.5°
µ = 0.27 mm−1
T = 123 K
Block, colourless
0.30 × 0.23 × 0.23 mm
Data collection
Rigaku R-AXIS Spider
diffractometer
Radiation source: sealed tube
Graphite monochromator
Detector resolution: 10.0000 pixels mm-1
ω scans and/or φ scans
Absorption correction: multi-scan
(ABSCOR; Higashi, 2001)
Tmin = 0.924, Tmax = 0.941
7362 measured reflections
2551 independent reflections
2296 reflections with I > 2σ(I)
Rint = 0.043
θmax = 25.0°, θmin = 2.2°
h = −17→17
k = −12→11
l = −20→22
Refinement
Refinement on F2
Least-squares matrix: full
R[F2 > 2σ(F2)] = 0.049
wR(F2) = 0.135
S = 1.24
2551 reflections
183 parameters
0 restraints
Primary atom site location: structure-invariant
direct methods
Secondary atom site location: difference Fourier
map
Hydrogen site location: inferred from
neighbouring sites
H-atom parameters constrained
w = 1/[σ2(Fo2) + 10.5312P]
where P = (Fo2 + 2Fc2)/3
(Δ/σ)max < 0.001
Δρmax = 0.41 e Å−3
Δρmin = −0.42 e Å−3
Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full
covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and
torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry.
An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2,
conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2σ(F2) is
used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based
on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)
xyzU
iso*/Ueq
Cl1 0.5000 0.80128 (11) 0.7500 0.0264 (3)
P1 0.53916 (5) 0.32003 (8) 0.82724 (4) 0.0175 (2)
N1 0.5000 0.2594 (4) 0.7500 0.0200 (8)
C1 0.45695 (19) 0.4133 (3) 0.86442 (16) 0.0177 (6)
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Acta Cryst. (2010). E66, o3185
C2 0.4358 (2) 0.5349 (3) 0.83690 (17) 0.0206 (7)
H2 0.4700 0.5724 0.8038 0.030 (3)*
C3 0.3645 (2) 0.6011 (3) 0.85815 (19) 0.0262 (8)
H3 0.3505 0.6844 0.8399 0.030 (3)*
C4 0.3135 (2) 0.5461 (4) 0.90596 (19) 0.0293 (8)
H4 0.2639 0.5908 0.9193 0.030 (3)*
C5 0.3353 (2) 0.4258 (3) 0.9342 (2) 0.0288 (8)
H5 0.3009 0.3891 0.9675 0.030 (3)*
C6 0.4070 (2) 0.3582 (3) 0.91427 (18) 0.0258 (7)
H6 0.4220 0.2761 0.9340 0.030 (3)*
C7 0.57029 (19) 0.1897 (3) 0.88839 (17) 0.0182 (7)
C8 0.6079 (2) 0.2160 (3) 0.96055 (18) 0.0247 (7)
H8 0.6183 0.3018 0.9758 0.030 (3)*
C9 0.6297 (2) 0.1184 (3) 1.00954 (18) 0.0260 (7)
H9 0.6548 0.1365 1.0585 0.030 (3)*
C10 0.6148 (2) −0.0064 (3) 0.98669 (19) 0.0261 (8)
H10 0.6298 −0.0738 1.0204 0.030 (3)*
C11 0.5784 (2) −0.0344 (3) 0.91551 (19) 0.0242 (7)
H11 0.5685 −0.1204 0.9005 0.030 (3)*
C12 0.5563 (2) 0.0643 (3) 0.86618 (18) 0.0224 (7)
H12 0.5316 0.0457 0.8171 0.030 (3)*
C13 0.6391 (2) 0.4148 (3) 0.82560 (17) 0.0216 (7)
C14 0.6520 (2) 0.5357 (3) 0.85535 (18) 0.0232 (7)
H14 0.6081 0.5726 0.8804 0.030 (3)*
C15 0.7303 (2) 0.6030 (3) 0.8482 (2) 0.0299 (8)
H15 0.7385 0.6868 0.8674 0.030 (3)*
C16 0.7957 (2) 0.5487 (4) 0.8137 (2) 0.0314 (9)
H16 0.8488 0.5950 0.8098 0.030 (3)*
C17 0.7839 (2) 0.4266 (3) 0.78468 (19) 0.0275 (8)
H17 0.8292 0.3888 0.7616 0.030 (3)*
C18 0.7054 (2) 0.3602 (3) 0.78966 (18) 0.0249 (7)
H18 0.6964 0.2777 0.7688 0.030 (3)*
Atomic displacement parameters (Å2)
U11 U22 U33 U12 U13 U23
Cl1 0.0250 (6) 0.0205 (6) 0.0352 (7) 0.000 0.0095 (5) 0.000
P1 0.0157 (4) 0.0178 (4) 0.0194 (4) 0.0007 (3) 0.0037 (3) 0.0004 (3)
N1 0.0140 (17) 0.026 (2) 0.0199 (19) 0.000 0.0030 (14) 0.000
C1 0.0184 (15) 0.0189 (16) 0.0147 (14) 0.0012 (12) −0.0006 (12) −0.0041 (13)
C2 0.0217 (16) 0.0205 (17) 0.0194 (16) −0.0022 (13) 0.0028 (13) −0.0014 (14)
C3 0.0228 (16) 0.0240 (18) 0.0309 (18) 0.0045 (14) 0.0014 (14) −0.0018 (15)
C4 0.0186 (16) 0.036 (2) 0.033 (2) 0.0056 (14) 0.0048 (14) −0.0104 (17)
C5 0.0274 (18) 0.0265 (18) 0.036 (2) −0.0023 (15) 0.0161 (15) −0.0018 (17)
C6 0.0232 (17) 0.0279 (18) 0.0270 (18) 0.0008 (14) 0.0057 (14) 0.0038 (15)
C7 0.0161 (15) 0.0199 (16) 0.0192 (16) 0.0005 (12) 0.0044 (12) 0.0004 (13)
C8 0.0263 (17) 0.0210 (17) 0.0272 (18) −0.0010 (14) 0.0055 (14) 0.0006 (15)
C9 0.0280 (18) 0.0304 (19) 0.0188 (16) 0.0008 (14) 0.0012 (13) 0.0025 (15)
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C10 0.0230 (17) 0.0273 (18) 0.0287 (19) 0.0028 (14) 0.0062 (14) 0.0135 (15)
C11 0.0252 (17) 0.0151 (16) 0.0330 (19) 0.0000 (13) 0.0072 (14) 0.0033 (14)
C12 0.0177 (15) 0.0261 (18) 0.0236 (17) −0.0016 (13) 0.0036 (13) −0.0018 (15)
C13 0.0163 (15) 0.0246 (17) 0.0238 (17) 0.0001 (13) 0.0026 (12) 0.0033 (14)
C14 0.0235 (17) 0.0186 (16) 0.0276 (18) −0.0014 (13) 0.0040 (13) −0.0024 (14)
C15 0.0240 (17) 0.0280 (19) 0.036 (2) 0.0052 (15) −0.0003 (15) −0.0018 (16)
C16 0.0163 (16) 0.043 (2) 0.033 (2) −0.0046 (15) −0.0021 (14) 0.0123 (17)
C17 0.0205 (16) 0.032 (2) 0.0305 (19) 0.0033 (14) 0.0050 (14) 0.0089 (16)
C18 0.0195 (16) 0.0311 (19) 0.0237 (17) 0.0026 (14) 0.0020 (13) −0.0027 (15)
Geometric parameters (Å, º)
P1—N1 1.5984 (18) C8—H8 0.9500
P1—C7 1.795 (3) C9—C10 1.385 (5)
P1—C1 1.802 (3) C9—H9 0.9500
P1—C13 1.811 (3) C10—C11 1.384 (5)
N1—P1i1.5984 (18) C10—H10 0.9500
C1—C2 1.394 (4) C11—C12 1.390 (5)
C1—C6 1.409 (5) C11—H11 0.9500
C2—C3 1.390 (5) C12—H12 0.9500
C2—H2 0.9500 C13—C14 1.386 (5)
C3—C4 1.390 (5) C13—C18 1.410 (4)
C3—H3 0.9500 C14—C15 1.401 (5)
C4—C5 1.387 (5) C14—H14 0.9500
C4—H4 0.9500 C15—C16 1.383 (5)
C5—C6 1.392 (5) C15—H15 0.9500
C5—H5 0.9500 C16—C17 1.392 (5)
C6—H6 0.9500 C16—H16 0.9500
C7—C12 1.386 (4) C17—C18 1.391 (5)
C7—C8 1.401 (4) C17—H17 0.9500
C8—C9 1.377 (5) C18—H18 0.9500
N1—P1—C7 106.82 (17) C8—C9—C10 119.3 (3)
N1—P1—C1 112.50 (12) C8—C9—H9 120.3
C7—P1—C1 107.33 (15) C10—C9—H9 120.3
N1—P1—C13 113.24 (13) C11—C10—C9 121.1 (3)
C7—P1—C13 107.11 (14) C11—C10—H10 119.5
C1—P1—C13 109.49 (15) C9—C10—H10 119.5
P1—N1—P1i133.0 (3) C10—C11—C12 119.5 (3)
C2—C1—C6 120.2 (3) C10—C11—H11 120.3
C2—C1—P1 119.2 (2) C12—C11—H11 120.3
C6—C1—P1 120.2 (2) C7—C12—C11 120.1 (3)
C3—C2—C1 119.7 (3) C7—C12—H12 119.9
C3—C2—H2 120.1 C11—C12—H12 119.9
C1—C2—H2 120.1 C14—C13—C18 119.7 (3)
C4—C3—C2 120.4 (3) C14—C13—P1 124.1 (2)
C4—C3—H3 119.8 C18—C13—P1 116.1 (3)
C2—C3—H3 119.8 C13—C14—C15 119.5 (3)
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C5—C4—C3 119.9 (3) C13—C14—H14 120.3
C5—C4—H4 120.0 C15—C14—H14 120.3
C3—C4—H4 120.0 C16—C15—C14 120.7 (3)
C4—C5—C6 120.7 (3) C16—C15—H15 119.6
C4—C5—H5 119.6 C14—C15—H15 119.6
C6—C5—H5 119.6 C15—C16—C17 120.2 (3)
C5—C6—C1 119.0 (3) C15—C16—H16 119.9
C5—C6—H6 120.5 C17—C16—H16 119.9
C1—C6—H6 120.5 C18—C17—C16 119.6 (3)
C12—C7—C8 119.5 (3) C18—C17—H17 120.2
C12—C7—P1 121.5 (2) C16—C17—H17 120.2
C8—C7—P1 118.9 (2) C17—C18—C13 120.3 (3)
C9—C8—C7 120.5 (3) C17—C18—H18 119.9
C9—C8—H8 119.8 C13—C18—H18 119.9
C7—C8—H8 119.8
C7—P1—N1—P1i−179.94 (11) C12—C7—C8—C9 −0.9 (5)
C1—P1—N1—P1i62.54 (12) P1—C7—C8—C9 177.8 (2)
C13—P1—N1—P1i−62.27 (13) C7—C8—C9—C10 0.4 (5)
N1—P1—C1—C2 −76.9 (3) C8—C9—C10—C11 0.1 (5)
C7—P1—C1—C2 165.9 (2) C9—C10—C11—C12 −0.1 (5)
C13—P1—C1—C2 50.0 (3) C8—C7—C12—C11 0.9 (5)
N1—P1—C1—C6 95.5 (3) P1—C7—C12—C11 −177.8 (2)
C7—P1—C1—C6 −21.7 (3) C10—C11—C12—C7 −0.4 (5)
C13—P1—C1—C6 −137.7 (3) N1—P1—C13—C14 132.3 (3)
C6—C1—C2—C3 −0.8 (5) C7—P1—C13—C14 −110.2 (3)
P1—C1—C2—C3 171.6 (2) C1—P1—C13—C14 5.9 (3)
C1—C2—C3—C4 −0.8 (5) N1—P1—C13—C18 −46.0 (3)
C2—C3—C4—C5 1.7 (5) C7—P1—C13—C18 71.5 (3)
C3—C4—C5—C6 −1.0 (5) C1—P1—C13—C18 −172.5 (2)
C4—C5—C6—C1 −0.5 (5) C18—C13—C14—C15 1.1 (5)
C2—C1—C6—C5 1.4 (5) P1—C13—C14—C15 −177.2 (3)
P1—C1—C6—C5 −170.9 (3) C13—C14—C15—C16 −1.8 (5)
N1—P1—C7—C12 −2.0 (3) C14—C15—C16—C17 0.8 (5)
C1—P1—C7—C12 118.9 (3) C15—C16—C17—C18 1.0 (5)
C13—P1—C7—C12 −123.6 (3) C16—C17—C18—C13 −1.7 (5)
N1—P1—C7—C8 179.3 (2) C14—C13—C18—C17 0.7 (5)
C1—P1—C7—C8 −59.8 (3) P1—C13—C18—C17 179.1 (3)
C13—P1—C7—C8 57.7 (3)
Symmetry code: (i) −x+1, y, −z+3/2.

Supplementary resources (2)

... Crystals of TPEAC · Cl and TBAC · Cl were obtained by evaporation of methanol at room temperature in the glove box. The crystal structures of PPN · Cl [26] and TBA · Cl [27] were added as references. TPEAC · Cl and TBAC · Cl crystallize in orthorhombic space group Pbca and monoclinic space group C12/c1, respectively. ...
Article
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Organic halide salts in combination with metal or organic compound are the most common and essential catalysts in ring‐opening copolymerizations (ROCOP). However, the role of organic halide salts was neglected. Here, we have uncovered the complex behavior of organic halides in ROCOP of epoxides or aziridine with cyclic anhydride. Coordination of the chain‐ends to cations, electron‐withdrawing effect, leaving ability of halide atoms, chain‐end basicity/nucleophilicity, and terminal steric hindrance cause three types of side reactions: single‐site transesterification, substitution, and elimination. Understanding the complex functions of organic halide salts in ROCOP led us to develop highly active and selective aminocyclopropenium chlorides as catalysts/initiators. Adjustable H‐bonding interactions of aminocyclopropenium with propagating anions and epoxides create chain‐end coordination process that generate highly reactive carboxylate and highly selective alkoxide chain‐ends.
... In the past we have used the large and only weakly coordinating bis(triphenyl-λ 5 -phosphanylidene)ammonium cation ([Ph 3 PNPPh 3 ] + ≡ [PNP] + ) to structurally investigate small and simple anions [25,[30][31][32][33]. The concept of weakly coordinating cations is of current interest [34][35][36] ...
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The previously unknown dianions [H6Cl4O2]2− and [H6Br4O2]2− were prepared as their bis(triphenyl-λ5-phosphanylidene)ammonium ([Ph3PNPPh3]+ ≡ [PNP]+) salts from [PNP]+ halides and aqueous hydrochloric or hydrobromic acid, respectively. The crystal structures of the two salts [PNP]2[H6Cl4O2] and [PNP]2[H6Br4O2] are reported. The unprecedented dianions [H6Cl4O2]2− and [H6Br4O2]2−, which represent a section of the structure of halide-rich hydrochloric or hydrobromic acid, are discussed. Quantum-chemical calculations support the findings. The crystal structure of [PNP][HBr2], a rare example for a crystallographically determined hydrogen dibromide structure, is presented as well.Graphical Abstract The dianions [H6Cl4O2]2− and [H6Br4O2]2− were prepared as their [PNP]+ salts and structurally characterized.
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Organic halide salts in combination with metal or Lewis acids are the most common and essential catalysts in ring‐opening copolymerizations (ROCOP). However, the role of organic halide salts was neglected. Here, we have uncovered the complex behavior of organic halide in ROCOP of epoxides or aziridines with cyclic anhydrides. Coordination of the chain‐end cations, electron‐withdrawing effect, leaving ability of halide atoms, chain‐end basicity/nucleophilicity, and terminal steric hindrance cause three types of side reactions: single‐site transesterification, substitution, and elimination. Understanding the complex functions of organic halide salts in ROCOP led us to develop highly active and selective aminocyclopropenium chlorides as catalysts/initiators. Adjustable H‐bonding interactions of aminocyclopropenium with propagating anions and epoxides create chain‐end coordination processes that generate highly reactive carboxylate and highly selective alkoxide chain ends.
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The halogen bond has previously been explored as a versatile tool in crystal engineering and anion coordination chemistry, with mechanochemical synthetic techniques having been shown to provide convenient routes towards cocrystals. In an effort to expand our knowledge on the role of halogen bonding in anion coordination, here we explore a series of cocrystals formed between 3‐iodoethynylpyridine and 3‐iodoethynylbenzoic acid with halide salts. In total, we report the single‐crystal X‐ray structures of six new cocrystals prepared by mechanochemical ball milling, with all structures exhibiting C≡C−I⋅⋅⋅X− (X=Cl, Br) halogen bonds. Whereas cocrystals featuring a pyridine group favoured the formation of discrete entities, cocrystals featuring a benzoic acid group yielded an alternation of halogen and hydrogen bonds. The compounds studied herein were further characterized by 13C and 31P solid‐state nuclear magnetic resonance, with the chemical shifts offering a clear and convenient method of identifying the occurrence of halogen bonding, using the crude product obtained directly from the mechanochemical ball milling. Whereas the 31P chemical shifts were quickly able to identify the occurrence of cocrystallization, 13C solid‐state NMR was diagnostic of both the occurrence of halogen bonding and of hydrogen bonding. Cocrystal engineering using the 3‐iodoethynyl moiety as a halogen bond donor is explored using mechanochemistry. X‐ray diffraction and solid‐state nuclear magnetic resonance spectroscopy highlight the roles of the halogen bonds and hydrogen bonds in determining the resulting structures.
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Metathesis reactions of [PNP]Cl ([PNP] ⁺ ≡ bis(triphenyl- λ⁵ -phosphanylidene)ammonium) with Na 2 [SO 4 ] or K[HSO 4 ] in water yield [PNP] 2 [SO 4 ] and [PNP][HSO 4 ], respectively, as colorless solids. Reactions under basic conditions lead to a partial decomposition of the weakly coordinating [PNP] ⁺ cation. N -Diphenylphosphine-triphenylphosphazene, triphenylphosphinimine, and benzene were identified as decomposition products by NMR spectroscopy. The compounds [PNP] 2 [SO 4 ] and [PNP][HSO 4 ] were characterized by multinuclear NMR and vibrational spectroscopy. [PNP][HSO 4 ] could be crystallized from acetonitrile-diethyl ether giving single crystals with and without additional acetonitrile solvate molecules. The [HSO 4 ] ⁻ anions form dimers in the solid state in both structures, which are held together by O–H⋯O hydrogen bonds. At T = 127 K the [HSO 4 ] ⁻ anions in the crystal structure of solvate free [PNP][HSO 4 ] are ordered, while at T = 300 K and in the structure containing additional acetonitrile solvate molecules a disorder of the [HSO 4 ] ⁻ anions over two positions is observed, for the latter even at 150 K.
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So far unknown bis(triarylphosphoranylidene)iminium cations [PPN]+ with one fluorine atom in para- ([PPN-1F]+), two in meta- ([PPN-2F]+) or three in para- and meta- position of the phenyl rings ([PPN-3F]+) were obtained by a new developed one-pot reaction. For a full characterization of these first mentioned halogenated [PPN]+ cations IR and Raman spectroscopy in comparison with quantum-chemical calculations as well as ESI+ spectrometry, NMR spectroscopy and single crystal X-ray diffraction were used. To test the quality as good weakly coordinating cations (WCCs) and the associated ability to stabilize labile anions the electrostatic potential as well as the fluoride ion affinity were calculated and compared with the results of the unsubstituted and the so far unknown perfluorinated [PPN-5F]+ cations.
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While hydrogen bridging is very common in boron chemistry, halogen bridging is rather rare. The simplest halogen-bridged boron compounds are the [B2X7](-) anions (X = F, Cl, Br, I), of which only [B2F7](-) has been reported to exist experimentally. In this paper a detailed theoretical and synthetic study on the [B2X7](-) anions is presented. The structures of [B2X7](-) anions have been calculated at the MP2/def2-TZVPP level of theory, and their local minima have been shown to be of C2 symmetry in all cases. The bonding situation varies significantly between the different anions. While in [B2F7](-) the bonding is mainly governed by electrostatics, the charge is almost equally distributed over all atoms in [B2I7](-) and additional weak iodine···iodine interactions are observed. This was shown by an atoms in molecules (AIM) analysis. The thermodynamic stability of the [B2X7](-) anions was estimated in all phases (gas, solution, and solid state) based on quantum-chemical calculations and estimations of the lattice enthalpies using a volume-based approach. In the gas phase the formation of [B2X7](-) anions from [BX4](-) and BX3 is favored in accord with the high Lewis acidity of the BX3 molecules. In solution and in the solid state only [B2F7](-) is stable against dissociation. The other three anions are borderline cases, which might be detectable under favorable conditions. However, experimental attempts to identify [B2X7](-) (X = Cl, Br, I) anions in solution by (11)B NMR spectroscopy and to prepare stable [PNP][B2X7] salts failed.
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Three new compounds containing the bis(triphenylphosphane)iminium cation (PPN(+)) with ClO4(-), BF4(-) and [AgCl2](-) as counter anions have been synthesized and structurally characterized. The two derivatives with ClO4(-) and BF4(-) were found to be isostructural by single crystal X-ray diffraction. Interestingly, the three compounds show extremely potent antiproliferative effects against the human cancer cell line SKOV3. To gain insights into the possible mechanisms of biological action, several intracellular targets have been considered. Thus, DNA binding has been evaluated, as well as the effects of the compounds on the mitochondrial function. Furthermore, the compounds have been tested as possible inhibitors of the seleno-enzyme thioredoxin reductase.
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The title crystal structure is a new triclinic polymorph of [(Ph3P)2N]Cl·(B(OH)3) or C36H30NP2⁺·Cl⁻·BH3O3. The crystal structure of the ortho­rhom­bic polymorph was reported by [Andrews et al. (1983). Acta Cryst. C39, 880–882]. In the crystal, the [(Ph3P)2N]⁺ cations have no significant contacts to the chloride ions nor to the boric acid mol­ecules. This is indicated by the P—N—P angle of 137.28 (8)°, which is in the expected range for a free [(Ph3P)2N]⁺ cation. The boric acid mol­ecules form inversion dimers via pairs of O—H⋯O hydrogen bonds, and each boric acid mol­ecule forms two additional O—H⋯Cl hydrogen bonds to one chloride anion. These entities fill channels, created by the [(Ph3P)2N]⁺ cations, along the c-axis direction.
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A new synthesis of bis(triphenyl-λ(5)-phosphanylidene)ammonium fluoride ((Ph3PNPPh3)F, abbreviated as (PNP)F), is described. The title compound has been fully characterized by multinuclear NMR spectroscopy, vibrational spectroscopy, elemental analysis and single crystal and powder X-ray diffraction for the first time. In the solid state (PNP)F exists as a covalent molecular compound, in which the fluoride ion is asymmetrically bonded to the two phosphorus atoms of the [PNP](+) cation. The phosphorus-fluorine bond with 181.98(13) pm is surprisingly long and the longest P-F bond in any phosphorane. (PNP)F can be assumed to be a very good source of reactive fluoride. To investigate the fluoride ion donating properties, (PNP)F was reacted with a range of different fluoromethylsilanes MenSiF4-n (n = 0-4). Reactions of (PNP)F with the fluoromethylsilanes were performed in aceto- or propionitrile and in 1,2-dimethoxyethane under inert conditions. The resulting hypervalent fluoromethylsilicates [MenSiF5-n](-) (n = 0-3) were fully characterized by multinuclear NMR and vibrational spectroscopy and single crystal X-ray diffraction. From the reaction of (PNP)F with Me4Si in acetonitrile, the starting materials were recovered unchanged. To aid the understanding of the experimental results the fluoride ion affinities (FIA) for these silanes have been calculated by DFT calculations on the PBE0/def2-TZVPP level of theory. The fluoride ion affinity in the series of MenSiF4-n (n = 0-4) decreases with the number of methyl groups and is too low for Me4Si to bind a fluoride ion under these reaction conditions.
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The title compound, C36H30NP2⁺·Br⁻·C2H3N, crystallized from a CH3CN/OEt2 solution as an acetonitrile solvate. The central P—N—P angle [142.88 (10)°] is significantly larger than in the corresponding chloride and iodide structures.
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The title compound, C36H30NP2⁺·I⁻, was obtained accidently from crystallization of a reaction mixture containing [(Ph3P)2N]OH and B(OH)3, which was contaminated with MeI. There are two independent [(Ph3P)2N]⁺ cations and two I⁻ anions within the asymmetric unit. The central PNP angles are non-linear [137.6 (2) and 134.4 (2)°] and the phenyl substituents on P centres adopt different conformations within these two cations.
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The Cambridge Structural Database (CSD) now contains data for more than a quarter of a million small-molecule crystal structures. The information content of the CSD, together with methods for data acquisition, processing and validation, are summarized, with particular emphasis on the chemical information added by CSD editors. Nearly 80% of new structural data arrives electronically, mostly in CIF format, and the CCDC acts as the official crystal structure data depository for 51 major journals. The CCDC now maintains both a CIF archive (more than 73000 CIFs dating from 1996), as well as the distributed binary CSD archive; the availability of data in both archives is discussed. A statistical survey of the CSD is also presented and projections concerning future accession rates indicate that the CSD will contain at least 500000 crystal structures by the year 2010.
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An account is given of the development of the SHELX system of computer programs from SHELX-76 to the present day. In addition to identifying useful innovations that have come into general use through their implementation in SHELX, a critical analysis is presented of the less-successful features, missed opportunities and desirable improvements for future releases of the software. An attempt is made to understand how a program originally designed for photographic intensity data, punched cards and computers over 10000 times slower than an average modern personal computer has managed to survive for so long. SHELXL is the most widely used program for small-molecule refinement and SHELXS and SHELXD are often employed for structure solution despite the availability of objectively superior programs. SHELXL also finds a niche for the refinement of macromolecules against high-resolution or twinned data; SHELXPRO acts as an interface for macromolecular applications. SHELXC, SHELXD and SHELXE are proving useful for the experimental phasing of macromolecules, especially because they are fast and robust and so are often employed in pipelines for high-throughput phasing. This paper could serve as a general literature citation when one or more of the open-source SHELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.
Article
Analysis of the 752 crystals in the Cambridge Structural Database containing [Ph3PNPPh3]+ ([PPN]+) cations has revealed mutually attractive interactions between the cations leading to the formation of supramolecular motifs. The cation is flexible due to P–N–P bending: calculation of single point energies for an idealised [H3PNPH3]+ fragment show a flat energy well for the cation, with there being less than 1 kcal mol−1 difference in energy between P–N–P angles of 130–180°. The most populated conformation is that with a P–N–P angle in the range 140–145°. The types of inter-cation interaction can be classified by a combination of the N–PP angle, the N–PP–N torsion angle and the four intermolecular PP distances between neighbouring cations. Interactions with an N–PP angle of greater than 125° indicate a sixfold phenyl embrace (6PE), whilst those at more acute angles form expanded phenyl embraces with neighbouring cations either parallel (PEPE) or orthogonal (OEPE). The PEPE and OEPE are differentiated by torsion angle or intermolecular PP separations. Computation of the energies of attraction between the cations gives values in the ranges 7.0–10.5, 7.9–11.1 and 8.6–13.0 kcal mol−1 for the 6PE, OEPE and PEPE respectively. The individual embraces combine to form zigzag chains of cations leading to either columnar or layered structures. The crystal lattice formed does not depend on anion size or charge.
Private communication (refcode: NAVMEM ). CCDC
  • K M Carroll
  • A L Rheingold
  • M B Allen
Carroll, K. M., Rheingold, A. L. & Allen, M. B. (1996). Private communication (refcode: NAVMEM ). CCDC, Cambridge, England.
  • K Brandenburg
  • H Putz
Brandenburg, K. & Putz, H. (2010). DIAMOND. Crystal Impact GbR, Bonn, Germany.