Chlorobis(triphenylphosphine)-nickel(I) tetrahydrofuran solvate and an unsolvated trigonal phase of chlorotris(triphenylphosphine)-nickel(I)

Article abstract of DOI:10.1107/S0108270100008350

In [NiCl(C₁₈H₁₅P)₂]·C₄H₈O, the Ni atom is coordinated by three ligands in a distorted trigonal-planar configuration, with a P-Ni-P angle of 111.52 (2)°. In [NiCl(C₁₈H₁₅P)₃], there are three independent molecules in the asymmetric unit, with each Ni-Cl bond on a crystallographic threefold rotation axis. Each Ni centre is tetrahedrally bound. The Ni atoms in both compounds have a d⁹ configuration and a formal oxidation state of Ni^I. A comparison is made between the form of [NiCl(PPh₃)₃] presented here and that of a known toluene solvate.

Full text of DOI:10.1107/S0108270100008350

metal-organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
pairs on the chloride ligand, which brings it in closer proxi-
mity to the metal than the corresponding P atoms. A similar
reasoning was proposed by Brammer & Stevens (1988) in
ISSN 0108-2701
Chlorobis(triphenylphosphine)-
nickel(I) tetrahydrofuran solvate and
an unsolvated trigonal phase of
chlorotris(triphenylphosphine)-
nickel(I)
their analysis of [NiCl2(PPh3)2]. Bulky ligands such as PR3
(R = Ph, Cy) or NR02 (R0 = Ph, SiMe3) can be used for stabi-
lizing low oxidation states and in many cases where the ligands
are not identical, a distorted trigonal±planar geometry results.
Thus, in the three-coordinate trigonal±planar nickel(I) species
[Ni{N(SiMe3)2}(PPh3)2] (Bradley et al., 1972) and the
nickel(II) complex [NiGe{N(SiMe3)2}2(PPh3)2] (Litz et al.,
1997), the PÐNiÐP bond angles are smaller than the
ZÐNiÐP angles (Z = N and Ge, respectively). By com-
parison, in the nickel(0) complex [Ni(PPh3)3] (Dick et al.,
1990) and the nickel(II) moiety [Ni(NPh2)3] (Hope et al.,
1985), all angles around the central nickel are close to 120ꢀ.
The shortest contacts to the nickel centre in (I) occur between
ortho-H atoms on the phenyl rings and nickel: Ni1Á Á ÁH12 2.84,
Dianne D. Ellis* and Anthony L. Spek
Bijvoet Center for Biomolecular Research, Department of Crystal and Structural
Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
Correspondence e-mail: d.d.ellis@chem.uu.nl
Received 17 May 2000
Accepted 8 June 2000
In [NiCl(C18H15P)2]ÁC4H8O, the Ni atom is coordinated by
three ligands in a distorted trigonal±planar con®guration, with
a PÐNiÐP angle of 111.52 (2)ꢀ. In [NiCl(C18H15P)3], there
are three independent molecules in the asymmetric unit, with
each NiÐCl bond on a crystallographic threefold rotation axis.
Each Ni centre is tetrahedrally bound. The Ni atoms in both
compounds have a d9 con®guration and a formal oxidation
state of NiI. A comparison is made between the form of
[NiCl(PPh3)3] presented here and that of a known toluene
solvate.
Ê
NiÁ Á ÁH14 2.94 and Ni1Á Á ÁH26 3.07 A. These are of a similar
magnitude as those observed in [Ni(PPh3)3] (Dick et al.,
1990).
The crystal and molecular structure of [NiCl(PPh3)3], (II),
studied at 150 K is isomorphous with the bromide analogue,
[NiBr(PPh3)3] (Mealli et al., 1983), measured at 293 K.
Compound (II) has slightly shorter cell dimensions [from the
Ê
different van der Waals radii of bromide (1.85 A) compared
Ê
with chloride (1.75 A) and temperature differences], and more
accurate s.u. values on all geometric parameters. There are
Comment
Aryl halides may be cyanated using sodium cyanide in the
presence of
a
catalyst such as tris(triphenylphos-
phine)nickel(0). An important step in the reaction mechanism
is the oxidative addition of an aryl halide to the zero-valent
nickel complex, to form chloro(aryl)bis(triphenylphosphine)-
nickel. Nickel(0) complexes can be stabilized with sterically
demanding phosphine ligands, even so, di- and trivalent
monomeric nickel complexes are relatively uncommon
compared with their palladium and platinum analogues,
possibly due to dif®culties in crystallization. Under fairly harsh
reaction conditions, the two title nickel(I) complexes, (I) and
(II), were formed as by-products in recrystallization processes
(van Soolingen, 1995).
In [NiCl(PPh3)2]ÁTHF (THF is tetrahydrofuran), (I) (Fig. 1),
the nickel ion is coordinated by two PPh3 groups with NiÐP
Ê
distances of 2.2091 (6) and 2.2012 (6) A, and a chloride ion
Ê
Ê
with an NiÐCl distance of 2.1481 (6) A, and lies 0.051 (1) A
out of the PÁ Á ÁPÁ Á ÁCl plane. Complex (I) shows a distorted
trigonal geometry; the PÐNiÐP angle of 111.52 (2)ꢀ is
signi®cantly smaller than the corresponding ClÐNiÐP angles
of 126.98 (2) and 121.33 (2)ꢀ. These angular differences are
thought to be caused by the space requirement of the lone
Figure 1
The displacement ellipsoid plot (PLATON; Spek, 2000) of (I) drawn at
the 50% probability level. H atoms have been omitted for clarity.
ꢁ
Acta Cryst. (2000). C56, 1067±1070
# 2000 International Union of Crystallography Printed in Great Britain ± all rights reserved 1067

metal-organic compounds
Figure 3
The unit cell of (II) projected down the c axis (PLATON; Spek, 2000).
Figure 2
are similar in both complexes, each having one NiÐPÐC
angle slightly wider than the other two. The orientation of the
triphenylphosphine fragments can be described using the
values associated with the NiÐPÐCipsoÐCortho torsion angles
(the smaller of the two values is chosen for this comparison).
In complex (I), these are 71.74 (17), 8.8 (2) and 27.07 (18)ꢀ for
P1, and 47.71 (18), 38.22 (17) and 53.23 (18)ꢀ for P2. All
the triphenylphosphine groups on P1 are orientated in the
same direction; those on P2 also have the same sense but the
signs are reversed (relative to P1) and the range of torsion
angles is fairly compact (the values lie around 45ꢀ). The phenyl
rings on P2 adopt the low-energy (propeller-type) conforma-
tion (Dunitz, 1995). The P1ÐC1 bond adopts an eclipsed
conformation with respect to the NiÐP2 bond [P2ÐNi1Ð
P1ÐC1 = 0.80 (8)ꢀ], whilst all the other PÐC bonds in (I) are
staggered. For complex (II), the NiÐPÐCipsoÐCortho values
are 32.2 (3), 76.2 (3) and 10.0 (3)ꢀ for P1 in molecule 1,
37.6 (3), 19.5 (3) and 80.5 (3) for P2 in molecule 2, and
78.4 (3), 8.5 (3) and 35.7 (3)ꢀ for P3 in molecule 3. The
torsion angles around each PÐC bond again show a wide
distribution, varying from 8 to 80ꢀ. Although these values are
comparable to those observed on P1 of complex (I), one of the
phenyl rings has a different pitch, and all the PÐC bonds in
(II) have staggered conformations with respect to the NiÐX
bonds (X = Cl or P).
A search for X2M(PPh3) trigonal±planar moieties and
X3M(PPh3) tetrahedral structures in the Cambridge Structural
Database (CSD version 5.18, 207 507 entries; Allen &
Kennard, 1993; where X is de®ned as any atom and M is any
transition metal) revealed 38 and 95 examples, respectively. To
our knowledge, only one other trigonal±planar nickel(I)
species, [Ni{N(SiMe3)2}(PPh3)2] (Bradley et al., 1972), has
been structurally characterized. The small number of trigonal±
planar fragments is consistent with the rarity of this coordi-
nation number: the only transition metals elements present
were from groups 10 and 11. Tetrahedral fragments, on the
other hand, occur more widely and encompass a more diverse
range of metals (from groups 6 to 12) in the periodic table.
The displacement ellipsoid plot (PLATON; Spek, 2000) of one molecule
of (II) drawn at the 50% probability level. H atoms have been omitted for
clarity. Symmetry operations used to generate equivalent positions: (A)
x + y, x, z; (B) y, x y, z.
three independent molecules in (II), with each Ni and Cl atom
on a crystallographic threefold rotation axis; Fig. 2 shows a
view of one molecule and Fig. 3 the packing diagram. Overall,
each molecule is tetrahedrally coordinated at the Ni atoms
and lies on the three (independent) crystallographic axes. The
orientation of the molecules in the asymmetric unit is the same
as in other [(Ph3P)3MX] derivatives (M/X = Co/Cl, Rh/NO,
Ir/NO, Ni/Br, Cu/Cl, Cu/Br and Ag/Br), with two MÐX
vectors pointing in one direction, whilst the third has the
opposite polarity.
The NiÐP and NiÐCl bond dimensions in (II) are consis-
tent within the three molecules, and are comparable to those
found in the (toluene) solvated form of the same compound,
[NiCl(PPh3)3]ÁC7H8 (Cassidy & Whitmire, 1991). The major
differences involve the bond angles: in (II), the ClÐNiÐP
value of 110.71 (3)ꢀ is larger than in the solvated form
[average ClÐNiÐP angle of 104.3 (40)ꢀ], and the PÐNiÐP
value of 108.21 (3)ꢀ is signi®cantly smaller than the value of
114.2 (55)ꢀ found in [NiCl(PPh3)3]ÁC7H8. Solvent, crystal-
lization procedures and other effects may be causing differ-
ences in the molecular environment. In the case of (II), the
symmetry of the molecule is coincident with the lattice
symmetry element, as observed in other [(Ph3E)3MX] (E = P,
As, Sb; X = halide or pseudo-halides FBF3, OClO3) moieties
[see, for example, Bowmaker et al. (1997)].
Comparisons of the geometric parameters in (I) and (II)
show some distinctions. The PÐC bonds in (I) are shorter on
average than those of (II) [mean values are 1.824 (7) versus
Ê
1.838 (2) A], with a broader spread of values in (I). The CÐ
PÐC bond angles are more consistent in both complexes
[103.7 (9) versus 102 (3)ꢀ], except that in (II), there is a wider
variation within each molecule. The average NiÐPÐC angles
ꢁ
1068 Ellis and Spek [NiCl(C18H15P)2]ÁC4H8O and [NiCl(C18H15P)3]
Acta Cryst. (2000). C56, 1067±1070

metal-organic compounds
Data collection
Experimental
Enraf±Nonius CAD-4 diffract-
ometer
w/2ꢂ scans
10742 measured re¯ections
5286 independent re¯ections
4500 re¯ections with I > 2ꢄ(I)
Rint = 0.055
ꢂmax = 27.49ꢀ
Complex (I) was formed by decomposition of chloro(phenyl)bis(tri-
phenylphosphine)nickel (van Soolingen, 1995) in a mixture of hexane
and THF at 313 K. Complex (II) was formed by decomposition
of chloro(2-thienyl)bis(triphenylphosphine)nickel (van Soolingen,
1995) in a mixture of hexane and toluene, with two equivalents of
triphenylphosphine, at 333 K.
h = 24 ! 23
k = 23 ! 24
l = 13 ! 0
3 standard re¯ections
frequency: 60 min
intensity decay: <1%
Re®nement
Compound (I)
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.031
wR(F2) = 0.066
S = 1.016
5286 re¯ections
533 parameters
H-atom parameters constrained
w = 1/[ꢄ2(Fo2) + (0.0260P)2
+ 0.0482P]
Crystal data
3
where P = (Fo2 + 2Fc2)/3
(Á/ꢄ)max = 0.001
[NiCl(C18H15P)2]ÁC4H8O
Dx = 1.341 Mg m
Mo Kꢁ radiation
Cell parameters from 25
re¯ections
Mr = 690.80
Monoclinic, P21=c
3
Ê
Áꢅmax = 0.30 e A
Ê
3
a = 16.4393 (16) A
Ê
0.52 e A
Áꢅmin
=
ꢂ = 11.56±12.23ꢀ
ꢃ = 0.769 mm
T = 150 (2) K
Ê
b = 11.2773 (12) A
1
Ê
c = 18.463 (2) A
ꢀ = 90.140 (9)ꢀ
V = 3422.9 (6) A
Z = 4
3
Ê
Plate, yellow
0.55 Â 0.55 Â 0.05 mm
X-ray data were collected using Zr ꢀ-®ltered Mo Kꢁ radiation. The
THF molecule in complex (I) is rotationally disordered, but re®ne-
ment of the atom positions corresponding to a second orientation
proved to be unstable. The unit cell of (I) is close to orthorhombic [ꢀ =
90.140 (9)ꢀ], but successive twinning matrices did not provide a stable
re®nement. Flack (1983) parameter re®nement included 272 Friedel
Data collection
Enraf±Nonius CAD-4 diffract-
ometer
w/2ꢂ scans
Absorption correction: scan
(North et al., 1968)
Tmin = 0.664, Tmax = 0.953
16135 measured re¯ections
7820 independent re¯ections
6179 re¯ections with I > 2ꢄ(I)
Rint = 0.036
max = 27.46ꢀ
ꢂ
h = 21 ! 21
k = 0 ! 14
pairs but was inconclusive and re®nement of the TWIN/BASF
l = 23 ! 23
3
Ê
Ê
parameter gave a value of 0.19 (2) A. Three solvent voids of 35.5 A
were found in complex (II) using PLATON (Spek, 2000). The closest
contacts to the main molecules are to H atoms on the phenyl groups.
The voids could not be assigned to any material used in the
preparation of the crystal. All H atoms were constrained and allowed
to ride on their C atoms with Uiso(H) = 1.2Ueq(C).
3 standard re¯ections
frequency: 60 min
intensity decay: <1%
Re®nement
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.096
S = 1.018
7820 re¯ections
406 parameters
H-atom parameters constrained
w = 1/[ꢄ2(Fo2) + (0.0469P)2
+ 2.2443P]
For both compounds, data collection: locally modi®ed CAD-4
Software (Enraf±Nonius, 1989); cell re®nement: SET4 (de Boer &
Duisenberg, 1984); data reduction: HELENA (Spek, 1997);
program(s) used to solve structure: DIRDIF (Beurskens et al., 1997);
program(s) used to re®ne structure: SHELXL97 (Sheldrick, 1997);
molecular graphics: PLATON (Spek, 2000); software used to prepare
material for publication: PLATON.
where P = (Fo2 + 2Fc2)/3
(Á/ꢄ)max = 0.002
3
Ê
Áꢅmax = 0.76 e A
3
Ê
0.60 e A
Áꢅmin
=
Compound (II)
Crystal data
Crystals were kindly provided by Dr J. van Soolingen, Dr T.
H. A. Peters and Professor Dr L. Brandsma, Utrecht
University, The Netherlands. The authors would also like to
thank Professor K. Whitmire for providing additional infor-
3
[NiCl(C18H15P)3]
Mr = 880.97
Trigonal, P3
Dx = 1.341 Mg m
Mo Kꢁ radiation
Cell parameters from 25
re¯ections
Ê
Ê
a = 19.0125 (8) A
b = 19.0125 (8) A
ꢂ = 11.71±13.88ꢀ
1
Ê
c = 10.4507 (7) A
ꢃ = 0.654 mm
T = 150 (2) K
ꢁ = 90.00ꢀ
V = 3271.6 (3) A
Z = 3
Table 2
Selected geometric parameters (A, ) for (II).
3
Ê
Block, yellow
0.50 Â 0.25 Â 0.25 mm
ꢀ
Ê
Ni1ÐCl1
Ni1ÐP1
Ni2ÐCl2
2.2933 (17)
2.3082 (9)
2.2858 (16)
Ni2ÐP2
Ni3ÐP3
Ni3ÐCl3
2.2887 (9)
2.2966 (9)
2.2982 (16)
Table 1
Selected geometric parameters (A, ) for (I).
ꢀ
Ê
Cl1ÐNi1ÐP1
P1ÐNi1ÐP1i
Cl2ÐNi2ÐP2
110.71 (3)
108.21 (3)
111.79 (3)
P2iiÐNi2ÐP2
P3iiiÐNi3ÐP3
P3ÐNi3ÐCl3
107.06 (3)
108.03 (3)
110.88 (3)
Ni1ÐCl1
Ni1ÐP2
2.1481 (6)
2.2012 (6)
Ni1ÐP1
2.2091 (6)
111.52 (2)
Cl1ÐNi1ÐP2
Cl1ÐNi1ÐP1
126.98 (2)
121.33 (2)
P2ÐNi1ÐP1
Ni1ÐP1ÐC111ÐC116
Ni1ÐP1ÐC111ÐC112
Ni1ÐP1ÐC121ÐC126
Ni1ÐP1ÐC121ÐC122
Ni1ÐP1ÐC131ÐC132
Ni2ÐP2ÐC211ÐC212
Ni2ÐP2ÐC211ÐC216
Ni2ÐP2ÐC221ÐC222
32.2 (3)
149.7 (3)
96.1 (3)
76.2 (3)
10.0 (3)
37.6 (3)
145.5 (3)
19.5 (3)
Ni2ÐP2ÐC221ÐC226
Ni2ÐP2ÐC231ÐC232
Ni2ÐP2ÐC231ÐC236
Ni3ÐP3ÐC321ÐC322
Ni3ÐP3ÐC321ÐC326
Ni3ÐP3ÐC331ÐC336
Ni3ÐP3ÐC331ÐC332
166.1 (2)
91.5 (3)
80.5 (3)
8.5 (3)
175.0 (3)
35.7 (3)
146.8 (3)
P2ÐNi1ÐP1ÐC1
Cl1ÐNi1ÐP2ÐC31
Cl1ÐNi1ÐP2ÐC19
Cl1ÐNi1ÐP2ÐC25
Ni1ÐP1ÐC1ÐC2
Ni1ÐP1ÐC1ÐC6
Ni1ÐP1ÐC7ÐC12
Ni1ÐP1ÐC7ÐC8
0.80 (8)
143.72 (8)
91.84 (8)
24.01 (8)
71.74 (17)
103.30 (16)
8.8 (2)
Ni1ÐP1ÐC13ÐC14
Ni1ÐP1ÐC13ÐC18
Ni1ÐP2ÐC19ÐC24
Ni1ÐP2ÐC19ÐC20
Ni1ÐP2ÐC25ÐC30
Ni1ÐP2ÐC25ÐC26
Ni1ÐP2ÐC31ÐC32
Ni1ÐP2ÐC31ÐC36
27.07 (18)
156.44 (16)
132.25 (16)
47.71 (18)
138.92 (16)
38.22 (17)
129.36 (15)
53.23 (18)
171.54 (17)
Symmetry codes: (i) y; x y; z; (ii) 1 y; 1 ‡ x y; z; (iii) 1 y; x y; z.
ꢁ
Acta Cryst. (2000). C56, 1067±1070
Ellis and Spek [NiCl(C18H15P)2]ÁC4H8O and [NiCl(C18H15P)3] 1069

metal-organic compounds
Bradley, D. C., Hursthouse, M. B., Smallwood, R. J. & Welch, A. J. (1972). J.
Chem. Soc. Chem. Commun. pp. 872±873.
Brammer, L. & Stevens, E. D. (1988). Acta Cryst. C45, 400±403.
Cassidy, J. M. & Whitmire, K. H. (1991). Acta Cryst. C47, 2094±2098.
Dick, D. G., Stephan, D. W. & Campana, C. F. (1990). Can. J. Chem. 68, 628±
632.
mation pertaining to [NiCl(PPh3)3]ÁC7H8. The investigations
were supported by the Netherlands Foundation for Chemical
Research (SON) with ®nancial aid from the Netherlands
Organization of Scienti®c Research (NWO).
Dunitz, J. D. (1995). X-ray Analysis and the Structure of Organic Molecules,
2nd ed. Basel: VCH.
Enraf±Nonius (1989). CAD-4 Software. Version 5.0. Enraf±Nonius, Delft, The
Netherlands.
Flack, H. D. (1983). Acta Cryst. A39, 876±881.
Hope, H., Olmstead, M. M., Murray, B. D. & Power, P. P. (1985). J. Am. Chem.
Soc. 107, 712±713.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: FG1605). Figures for molecules 2 and 3 of
compound (II) are also available. Services for accessing these data are
described at the back of the journal.
Litz, K. E., Bender, J. E. IV, Kampf, J. W. & Banaszak Holl, M. M. (1997).
Angew. Chem. Int. Ed. Engl. 36, 496±498.
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ꢁ
1070 Ellis and Spek [NiCl(C18H15P)2]ÁC4H8O and [NiCl(C18H15P)3]
Acta Cryst. (2000). C56, 1067±1070