Syntheses and properties of molecular nickel(II) hydride, methyl, and nickel(I) complexes supported by trimethylphosphane and (2-diphenylphosphanyl)thiophenolato and -naphtholato ligands

Article abstract of DOI:10.1016/j.jorganchem.2009.01.023

(2-Diphenylphosphanyl)thiophenol (P^pSH) or (3-diphenylphosphanyl)-2-thionaphthol (P^nSH) react with Ni(PMe₃)₄ to form NiH(P^pS)(PMe₃)₂ (1) or NiH(P^nS)(PMe₃)₂ (2). 1,3-Bis(diphenylphosphanyl)propane (P^P) replaces the monodentate phosphane ligands to give NiH(P^pS)(P^P) (3). NiMe(OMe)(PMe₃) or NiMe₂(PMe₃)₃ react with P^pSH to form NiMe(P^pS)(PMe₃) (4) and NiMe(P^pS)(PMe₃)₂ (5), respectively, and P^nSH affords NiMe(P^nS)(PMe₃)₂ (6), NiMe(P^nS)(PMe₃) (7). Dissociation of PMe₃ ligands induces transformation of 1 to Ni(P^pS)(PMe₃)₂ (8) and Ni(P^pS)₂. Crystal and molecular structures are given for 1, 5-8, and dynamic solution spectra (NMR, EPR) are discussed.

Full text of DOI:10.1016/j.jorganchem.2009.01.023

Journal of Organometallic Chemistry 694 (2009) 1869–1876
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Journal of Organometallic Chemistry
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Syntheses and properties of molecular nickel(II) hydride, methyl, and nickel(I)
complexes supported by trimethylphosphane and
(2-diphenylphosphanyl)thiophenolato and -naphtholato ligands
Peter B. Kraikivskii a,b,1, Markus Frey b, Hamdi A. Bennour b, Armin Gembus b, Ralf Hauptmann b,
Ingrid Svoboda c, Hartmut Fuess c, Vitaly V. Saraev a,1, Hans-Friedrich Klein b,
Department of Chemistry, Irkutsk State University, Str. K. Marksa, 1, Irkutsk 664003, Russia
*
a
b Eduard-Zintl-Institut für Anorganische und Physikalische Chemie der Technischen, Universität Darmstadt, Petersenstrasse 18, 64287 Darmstadt, Hessen, Germany
c Fachgebiet Strukturforschung, Fachbereich Material- und Geowissenschaften der Technischen Universität Darmstadt, Petersenstrasse 23, 64287 Darmstadt, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
(2-Diphenylphosphanyl)thiophenol (P^pSH) or (3-diphenylphosphanyl)-2-thionaphthol (P^nSH) react
with Ni(PMe3)4 to form NiH(P^pS)(PMe3)2 (1) or NiH(P^nS)(PMe3)2 (2). 1,3-Bis(diphenylphosphanyl)pro-
pane (P^P) replaces the monodentate phosphane ligands to give NiH(P^pS)(P^P) (3). NiMe(OMe)(PMe3)
or NiMe2(PMe3)3 react with P^pSH to form NiMe(P^pS)(PMe3) (4) and NiMe(P^pS)(PMe3)2 (5), respec-
tively, and P^nSH affords NiMe(P^nS)(PMe3)2 (6), NiMe(P^nS)(PMe3) (7). Dissociation of PMe3 ligands
induces transformation of 1 to Ni(P^pS)(PMe3)2 (8) and Ni(P^pS)2. Crystal and molecular structures are
given for 1, 5–8, and dynamic solution spectra (NMR, EPR) are discussed.
Received 9 November 2008
Received in revised form 10 January 2009
Accepted 16 January 2009
Available online 22 January 2009
Keywords:
Chelates
Nickel
Ó 2009 Elsevier B.V. All rights reserved.
P,S Ligands
Structure elucidation
1. Introduction
showed by Heimbach [7]. Others have considered the mechanism
of how cationic nickel complexes arise from Ni(PPh3)4 and boron
Although numerous examples of hydridonickel(II) complexes
have been described [1] no molecular compound of the type
NiH(X)(D)3 is known to date with X as anionic and D as neutral
donor ligands. Such species have been proposed as key intermedi-
ates in homogeneous catalysis (isomerisation and oligomerisation
of olefins), and the type NiH(X)(D)2 with [O,P]-chelating (OC
(CF3)2CH2PPh2) is represented by a crystal and molecular structure
[2,3]. This line of investigation is also prompted by the industrial
application of chelate chalcogenic ligands in SHOP-type processes
[4–6]. Using trimethylphosphane and chelating (2-diphenylphos-
phanyl)thiophenolato ligands we have found an easy access to
the title compounds and report here on their characterisation
and reactivity. Closely related methylnickel complexes were also
part of the study. Most authors, proposing mechanisms for the
reactions catalyzed with nickel complexes, avoid introducing
odd-electron species into the catalytic cycle. This reluctance is
understandable as long as transformation of nickel(0) and nickel(II)
states into that of nickel(I) is poorly understood.
trifluoride etherate [8]. Symproportionation of phosphine com-
plexes of Ni(0) and Ni(II) is regarded to be the key step. Also the
possibility of disproportionation of Ni(II) hydride complexes giving
ꢀ
Ni(I) species was shown for the systems Ni(PPh3)4 – Brønsted acid.
Chelate chalcogenic ligands allow one to prepare stable and readily
crystallized Ni(II) hydrides and Ni(II) alkyl complexes [9] as well.
These compounds can be good models to gain an insight into the
intrigue of how the elusive Ni(I) complexes come to exist. Besides,
there is an interesting and insufficiently explored question on the
possible formation of nickel(I) complexes in the systems with che-
lating ligands. This question is topical since nickel(I) species are
supposed to be involved in catalytic olefin oligomerisation reac-
tions [10–12]. The system under investigation is shown to contain
several molecular Ni(I) compounds. One of them could be isolated
and its molecular structure elucidated.
2. Results and discussion
The fundamental possibility of nickel(I) complex formation
through the symproportionation of Ni(0) and (II) complexes was
Reacting pentane solutions of Ni(PMe3)4 with (2-diphenylphos-
phanyl)thiophenol (Eq. (1)) gives a red solution from which upon
cooling deep red rectangular plates of 1 are grown in 10% yield.
With a fivefold excess of PMe3 improved yields of 30–40% are
reproducibly obtained, also with Ni(1,5-cyclooctadiene)(PMe3)2
* Corresponding author. Tel.: +49 6151 16 2173; fax: +49 6151 16 4173.
E-mail address: hfklein@ac1.ac.chemie.tu-darmstadt.de (H.-F. Klein).
1
DAAD Fellow (1.1 – 30.6.2007).
0022-328X/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2009.01.023

1870
P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
as Ni(0) reagent. Crystals of 1 are stable in air at 20 °C for at least
three days. Solutions of 1 in absolute pentane rapidly deposit green
Ni(P^pS)2 [13,14] with evolution of H2 but retain their red colour to
some degree (Eq. (3)). Under 1 bar of ethene the dismutation of 1 in
solution is accelerated, and under 1 bar of carbon monoxide the red
colour disappears. In a similar synthesis using (3-diphenylphos-
phanyl)2-thionaphthol (Eq. (2)) sparingly soluble 2 was isolated
showing similar chemical and spectral properties.
also observed in the crystal of 1 (Fig. 1). The most significant bond
length (Ni–H 1.503(32) Å) lies in the expected range, while Ni–P
and Ni–S bond lengths are found on the short side. The chelate ring
shows a relaxed bite angle (P1–Ni–S = 90.58(3)°) and with a sum of
internal angles (539.9°) close to the ideal value (540°) is planar.
An improved stability of the nickel hydride was attempted by
introducing 1,3-bis(diphenylphosphanyl)propane as a chelating
phosphane. In THF containing a fivefold excess of trimethylphos-
phane ligand displacement (Eq. (4)) is complete after five minutes,
and sparingly soluble 3 is isolated as orange solid in 90% yield.
Ph2
P
PPh2
When compared with 1 the m(NiH) band of 3 is shifted to higher
Ni(PMe3)4
Ni(PMe3)4
2 1
Ni(H)(PMe3)2
+
wavenumbers by 17 cmꢀ1, and the NiH resonance experiences a
low-field shift by 3 ppm. Both values are compatible with a re-
duced polarisation Ni+Hꢀ and a more covalent NiH bond in 3 aris-
- 2 PMe3
S
SH
1
ing from the stronger
p-accepting diphosphane ligand. In THF
ð1Þ
solution dismutation of 3 (Eq. (5)) starts after 20 minutes at
20 °C and appears to be only marginally slower than that of Eq.
(3), and again under 1 bar of ethene formation of Ni(P^pS)2 is
accelerated. From the mother liquor Ni[Ph2P(CH2)3PPh2]2 [15] is
crystallised in 64% yield. While the chelate bite (ꢁ90°) of the anio-
nic (P^pS) and (P^nS) ligands raises the thermal stability of hydri-
donickel(II) compounds with 18 metal valence electrons, the
diphosphane does not, because in its stable conformation the P-do-
nor atoms cannot span equatorial positions (ꢁ120°).
Ph2
P
PPh2
+
Ni
(H)(PMe3)2
- 2 PMe3
S
SH
2
ð2Þ
ð3Þ
Ph2
P
S
Ph2
Ni(PMe )
+
Ni
3 4
P
H
- H2
Ph2
S
P
Ph2P(CH2)3PPh2
+
Ni
1
P
Ph2
CH2
CH2
- 2 PMe3
ð4Þ
S
P
Ph2
The NiH function is recognized in the infrared spectra by con-
spicuous
(NiH) bands (1: 1893 cmꢀ1, 2: 1883 cmꢀ1) which in
CH2
m
the 1H NMR spectra correspond with doublet resonances (1:
2JHP = 41 Hz) indicating dissociation of trimethylphosphane li-
gands. At 203 K the signal becomes a doublet of triplets suggesting
a trigonal bipyramidal molecular geometry. This is confirmed in
the 31P spectrum of 1 and 2 recorded at 203 K where three P atoms
display two doublets of doublets. With the known angular depen-
dence of P,P coupling they appear to reside in a trigonal plane leav-
ing apical positions for S and H atoms. This molecular structure is
3
Ph2
P
S
2 3
Ni
Ni[Ph P(CH ) PPh ]
2 2
+
2
2 3
- H2
S
P
Ph2
ð5Þ
With information of the new hydridonickel compounds at hand
methylnickel complexes are expected to exist in similar composi-
tion. Syntheses as described earlier make these model compounds
readily accessible. (2-Diphenylphosphanyl)thiophenol reacts with
NiMe(OMe)(PMe3) (Eq. (6)) or NiMe2(PMe3)3 (Eq. (7)) to afford
methylnickel complexes 4 and 5 depending on the concentration
of trimethylphosphane in solution during synthesis and workup.
Yields are generally higher than with hydride 1 and accordingly
are subject to a concurring formation of Ni(P^pS)2. Sparingly solu-
ble 6 and 7 were obtained in a similar way (Eqs. (8) and (9)). The
orange crystals of 4, the red needles of 5, the red microcrystals of
6, and orange prismatic crystals are stable in air for at least two
weeks, as after that time characteristic infrared bands d(NiCH3)
at 1184 cmꢀ1 (4), at 1158 cmꢀ1 (5), at 1157 cmꢀ1 (6), and at
1219 cmꢀ1 (7) and in the 1H NMR at 20 °C doublets for NiCH3
groups (4: –0.37 ppm, 3J(PH) = 8 Hz; 5: –0.33 ppm, 3J(PH) = 9 Hz;
6: –0.20 ppm, 3J(PH) = 10 Hz; 7: –0.29 ppm, 3J(PH) = 10.5 Hz) are
fully present. Additional coupling with PMe3 phosphorus nuclei
is observed at 203 K indicating the expected ligand dynamics.
Ph2
P
PPh2
- MeOH
CH3
Ni
NiMe(OMe)(PMe3)
+
Fig. 1. Molecular structure of
1 (ORTEP plot with hydrogen atoms omitted);
PMe3
S
SH
selected bond lengths [Å] and angles [°]: Ni–H 1.46(3), Ni–S 2.237(9), Ni–P1
2.1465(8), Ni–P2 2.2132(9), Ni–P3 2.183(10); P1–Ni–S1 90.61(3), S1–Ni–H
174.6(12), P1–Ni–P2 116.05(3), P1–Ni–P3 127.09(4), P2–Ni–P3 115.47(4), P2–Ni–
H 90.5(12), P3–Ni–H 83.2(12).
4
ð6Þ

P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
1871
Ph2
P
PPh2
SH
CH3
Ni
NiMe2(PMe3)3
+
PMe3
- MeH
- PMe3
S
PMe3
5
ð7Þ
Ph2
P
PPh2
SH
CH3
Ni
NiMe2(PMe3)3
+
PMe3
- MeH
- PMe3
S
PMe3
6
ð8Þ
Ph2
P
PPh2
CH3
Ni
NiMe2(PMe3)3
+
- MeH
- 2PMe3
S
PMe3
SH
7
ð9Þ
Fig. 3. Molecular structure of
6
(ORTEP plot with hydrogen atoms omitted);
As compounds 5, 6, and 7 form crystals suitable for X-ray dif-
fraction we can compare the molecular structures (Figs. 2–4) of
closely related methylnickel complexes with 16 and 18 metal va-
lence electrons.
selected bond lengths [Å] and angles [°]: Ni–C23 1.977(5), Ni–S1 2.281(1), Ni–P1
2.186(1), Ni–P2 2.243(1), Ni–P3 2.253(1); P1–Ni–S1 84.18(5), P1–Ni–P2 120.36(5),
P1–Ni–P3 127.61(5), P2–Ni–P3 111.73(5), P1–Ni–C23 92.72(15), P2–Ni–C23
90.86(15), P3–Ni–C23 91.73(15), S1–Ni–C23 176.61(15).
Methylnickel complex 7 adopts a square planar geometry with
the methyl group trans to the sulfur donor (Fig. 2) while 5 and 6
show a trigonal bypyramidal arrangement with three equatorial
P donor atoms. NiC, NiS, and NiP bond lengths in 7 are on the short
side of expected values indicating the absence of steric crowding
and a balanced trans influence of the NiCH3 group. The sums of
internal angles in the three metallacycles (5: 537.8°, 6: 525.7°, 7:
538.5°) indicate planarity, and the bite angles are smaller than in
1. The NiS bond lengths in 5 and 6 are elongated by 8 pm when
compared with that in 7 and exceed that in 1 by 3 pm while the an-
gles SNiCH3 or SNiH show no significant difference. This observa-
tion suggests stronger NiS p-bonding in 7 than in 1 or 5, 6.
The present studies allow a conclusion of the most reasonable
ways to the alkyl and hydride nickel(II) complexes with thiopheno-
Fig. 4. Molecular structure of
7 (ORTEP plot with hydrogen atoms omitted);
selected bond lengths [Å] and angles [°]: Ni–S1 2.1997(7), Ni–P1 2.1403(7), Ni–P2
2.1888(8), C23–Ni 1.975(3); P1–Ni–P2 177.37(3), P1–Ni–S1 89.14(3), P2–Ni–S1
93.37(3), C23–Ni–S1 178.32(8), C23–Ni–P1 89.20(8), C23–Ni–P2 88.28(8).
lato and thionaphtholato ligands. Our experience in complex syn-
theses led us to test compounds 1 and 5 for generating Ni(I)
complexes. When the temperature was carefully controlled dihy-
drogen began evolving at ꢀ10 °C and a green solid of Ni(P^pS)2
precipitated. Filtering a decomposed solution of 1 affords micro-
crystalline Ni(P^pS)2 and a red solution containing free trimethyl-
phosphine that on cooling yields red crystals of the composition
Ni(P^pS)(PMe3)2 (8). These are air-sensitive and under argon
decompose above –10 °C. In the solid state and in solution 8 is
paramagnetic. In the studied system (Eq. (10)) complex 8 gives a
strong EPR signal (Fig. 5). In the ‘‘parallel” region of the spectrum
one can see a resolved HFS for three 31P nuclei, with two of them
Fig. 2. Molecular structure of
5 (ORTEP plot with hydrogen atoms omitted);
selected bond lengths [Å] and angles [°]: Ni–C25 2.007(5), Ni–S1 2.261(1), Ni–P1
2.164(1), Ni–P2 2.226 (1), Ni–P3 2.210 (1); P1–Ni–S1 88.47(5), P1–Ni–P2 115.62(4),
P1–Ni–P3 125.75(5), P2–Ni–P3 118.62(4), P1–Ni–C25 99.2(2), P2–Ni–C25 89.4(2),
P3–Ni–C25 89.8(2), S1–Ni–C25 177.2(2).

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P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
a
b
2700
3300
3500
22990000
33110000
3300
3500
37030700
2700
G
Fig. 5. Experimental (a) and model (b) EPR spectra of 8, solid state (powder),
T = 77 K. g = 2.008, g\ = 2.140, A (1P) = 45 G, A\ (1P) 6 23 G, A (2P) = 67 G, A\
k
k
k
(2P) = 57 G, T = 77 K.
Fig. 6. Molecular structure of
8 (ORTEP plot with hydrogen atoms omitted);
selected bond lengths [Å] and angles [°]: Ni–S1 2.241(1), Ni–P1 2.147(9), Ni–P2
2.184(1), Ni–P3 2.199(1); P1–Ni–S1 91.07(3), P1–Ni–P2 123.91(3), P1–Ni–P3
116.02(4), P2–Ni–P3 118.57(4), P1–Ni–S1 91.08(3), P2–Ni–S1 97.01(4), P3–Ni–S1
94.04(4).
being equivalent. The lines are non-uniformly broadened which
seems to result from a statistic dispersion of the geometric param-
eters of the Ni(I) complex included in a diamagnetic crystalline
matrix. In a monocrystalline state complex 8 gives almost no EPR
signal up to T = 5 K which is indicative of the antiferromagnetic
character of the exchange interaction between Ni(I) ions in the
crystal. In a powdered state complex 8 gives an intensive EPR sig-
nal even at T = 77 K. Hence the presence of HFS in the EPR spec-
ether solution under argon (Eq. (11)). This fact allows one to con-
clude that in the systems based on chelating P,S ligands nickel(I)
complexes are formed as decomposition products of nickel hy-
drides. The disproportionation appears to go through a dinickel
intermediate as shown in Eq. (10).
trum for
a solid sample of complex 8 is attributable to a
diamagnetic dilution of the system with monocrystals of complex
Ph2
8. The ratio between the components of the g-factor g\ > g ꢁ 2 is
Ph2
k
P
P
characteristic of tetrahedral Ni(I) complexes with
a trigonal
-100C, Ar
-H2
PMe3
PMe3
distortion [10]. The EPR based conclusion on the geometrical struc-
ture of complex 8 is in excellent agreement with the X-ray data
(see Fig. 6 ).
A rational synthesis proceeds by shifting an equilibrium to-
wards formation of 8 by adding trimethylphosphine to a mixture
of Ni(PMe3)4 and freshly prepared Ni(P^pS)2 in THF. Although all
attempts to isolate the dinickel intermediate (Eq. (10)) have so
far failed, the effect of excess trimethylphosphine points to its
presence.
2
2
Ni(H)(PMe3)2
Ni
S
1
S
8
ð11Þ
A similar disproportionation of the nickel hydride(II) NiH(CH3-
COO)(PPh3)2 giving a nickel(I) complex is known for the system
Ni(PPh3)4/CH3COOH [8]. Despite a great number of publications
devoted to nickel complex catalysts, the question of the structure
of the active species remains open. The majority of researchers tra-
ditionally assume that the oligomerization of olefins is performed
by Ni(II) hydride complexes and follows a Ni–H addition/elimina-
tion course. These assumptions are based on the classic works of
Tolman [16,17] and others concerned with NMR identification of
Ni(II) hydride model complexes [3–6]. On the other hand, accord-
ing to the EPR data, the process of formation of the nickel complex
catalysts includes the generation and stabilization of Ni(I) com-
plexes, independent of the metal valence state in the initial com-
pound [8–12].
Ph2
Ph2
P
P
S
S
- 2 PMe3
+ 2 PMe3
Ni
Ni
Ni
Ni(PMe3)4
+
S
S
P
Ph2
P
Ph2
Me3P
PMe3
- 2 PMe3
+ 2 PMe3
Ph2
P
PMe3
PMe3
Our research shows that the Ni(II) hydride complexes readily
turn into Ni(I) complexes that remain intact in solution. Conse-
quently, one should not neglect the chance that Ni(I) complexes
are directly relevant to the catalytic conversions of olefinic
hydrocarbons.
Ni
2
S
8
ð10Þ
To elucidate whether Ni(I) complex 8 can be obtained directly
from Ni(II) hydride 1 we examined transformations of dissolved
complex 1. A diethyl ether solution of complex 1, stable in a solid
form, was prepared at –10 °C (Method d, Section 3). After twenty
minutes, the EPR signal of complex 8 was recorded, after 2 h the
signal intensity peaked. Thus, complex 8 can be also prepared by
the slow disproportionation of hydride 1 at ꢀ10 °C in a diethyl
Photoactivation is one of activation methods for nickel complex
catalytic systems. A possibility of photoactivation of the nickel(II)
catalytic system in catalytic acetylene cyclotrimerization and eth-
ylene dimerization was demonstrated [18]. The formation of Ni(I)
species in this system was detected with EPR spectroscopy. Four-
teen different complexes [19] were obtained when Ni(II) com-
plexes were gamma-irradiated (2). Noteworthy, all the data were

P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
1873
gained for complex systems without isolation. As to information on
the possible photoreduction of Ni(II) organometallic complexes
into those of Ni(I), we failed to find it. In this connection, we stud-
ied the UV photoreduction of complex 5. A toluene solution of
complex 5 in a sealed quartz ampoule was UV-irradiated (Method
b, Section 3). After 2 h the EPR signal of Ni(I) complex 8 appeared. It
peaked after 8 h of the irradiation. Thus we also obtained the Ni(I)
complex through the photoreduction of Ni(II) alkyl complex 5 (Eq.
(12)).
and drying in vacuo. Yield 10.1 g (21%); m.p. 165–168 °C. IR (Nujol)
m
= 2547 cmꢀ1(SH). 1H NMR (200 MHz, CDCl3, 296 K): d 7.87–7.24
(m, 16H, CH), 4.10 (s, 1H, SH) ppm. 31P NMR (81 MHz, CDCl3,
296 K): d –11.7 (s). C22H17PS (344.4): Calc.: C, 76.72; H, 4.97.
Found: C, 76.58; H, 4.99%.
3.3. Hydrido(2-diphenylphosphanyl)thiophenolato[P,S]bis(trimethyl-
phosphane)nickel (1) [25]
Ni(PMe3)4 (1.30 g, 3.60 mmol) in pentane (80 mL) containing
1.4 g of trimethylphosphane was combined with (2-diphenylphos-
phanyl)thiophenol (1.05 g, 3.60 mmol) and stirred for 30 min. The
red solution was filtered and cooled to –27 °C to form light red
plates of 1. Yield 670 mg (37%); decomp. >65 °C. IR (Nujol)
Ph2
P
Ph2
P
CH3
PMe3
PMe3
hν
- CH3
Ni
.
Ni
ð12Þ
PMe3
PMe3
S
S
m
= 1893 cmꢀ1(NiH). 1H NMR (500 MHz, [D8]THF, 203 K): d 7.71–
8
5
6.86 (m, 14H, CH), 1.15 (s, 18H, PCH3), –19.9 (dt,2JP,H = 45 and
In closing we would like to point out that we did not anticipate
Ni(I) species to be formed so readily in the examined systems as it
proved to occur. Our study shows that chelate chalcogenic ligands
facilitate the generation of Ni(I) complexes.
The monovalent oxidation state of nickel has received increas-
ing attention in recent years, in part due to its active role in a
number of catalytic processes including biochemical reactions
[26–39,40], nickel mediated cross-coupling reactions to make
new C–C bonds [39,40–46], alkene oligomerization by heteroge-
neous [47–60] and homogeneous nickel catalysts [61–62], and
other processes [63–67]. We hope that the results presented here
will help to appreciate the role of Ni(I) in these processes.
54 Hz, 1H, NiH) ppm. 13C NMR (125 MHz, [D8]THF, 203 K): d
163.6 (d, JP,C = 51 Hz, C1), 140.6 (dt, JP,C = 34 Hz, JP,C = 10 Hz,
2
1
3
1
C2), 136.7 (d, JP,C = 44.9 Hz, C3), 133.8 (s, CH4), 133.1 (d,
3JP,C = 12.1 Hz, CH5), 130.1 (d, JP,C = 16.8 Hz, CH6), 129.3 (s, CH7),
3
3
2
129.1 (d, JP,C = 8.0 Hz, CH8), 128.9 (d, JP,C = 8.6 Hz, CH9), 120.0
(s, CH10), 15.6 (s, PCH3) ppm.
2
31P NMR (202 MHz, [D8]THF, 203 K): d = 57.5 (t, JP,P = 154 Hz,
2
1P, PPh), –14.4 (d, JP,P = 154 Hz, 2P, PMe) ppm. C24H33NiP3S
(505.2): Calc.: C, 57.06; H, 6.58; P, 18.39. Found: C, 57.80; H,
6.95; P, 17.81% (see Scheme 1).
3.4. Hydrido(3-diphenylphosphanyl)2-
thionaphtholato[P,S]bis(trimethylphosphane)nickel (2)
3. Experimental
Ni(PMe3)4 (430 mg, 1.18 mmol) in diethyl ether (30 mL) con-
taining 0.5 g of trimethylphosphane at –30 °C was combined with
(3-diphenylphosphanyl)2-thionaphthol (408 mg, 1.18 mmol) in
diethyl ether (50 mL). On warming, the mixture turned orange
red and was stirred at 20 °C for 16 h and filtered. From the filtrate
at –27 °C red crystals of 2 were obtained. Yield 560 mg (63%); de-
3.1. General procedures and materials
Standard vacuum techniques were used in manipulations of
volatile and air-sensitive materials. Ni(PMe3)4 [20], NiMe2(PMe3)3
[21], NiMe(OMe)(PMe3) [22], (2-diphenylphosphanyl)thiophenol
[23], (3-diphenylphosphanyl)2-thionaphthol [23] and were syn-
thesized according to literature procedures. C, H, P, S analyses of
air-sensitive solids were carried by H. Kolbe microanalytical labo-
ratory, Mülheim/Ruhr. Infrared spectra (4000–400 cmꢀ1), as ob-
tained from Nujol mulls between KBr discs, were recorded on a
Bruker FRA 106 spectrometer. Mass spectra were obtained on a
Varian MAT spectrometer. EPR spectra were recorded with Bruker
ESP 300E. The EPR spectra were simulated with our own program
[24], in which the hyperfine interaction (HFI) is limited to the sec-
ond-order term and where the main axes of the g-tensor and the
HFI tensors coincide.
comp. >75 °C. IR (Nujol)
m
= 1883 cmꢀ1(NiH). 1H NMR (500 MHz,
[D8]THF, 190 K): d 7.73–6.24 (m, 16H, CH), 1.01 (s, 18H, PCH3),
2
–19.9 (dt, JP,H = 40 and 50 Hz, 1H, NiH) ppm. 31P NMR (202 MHz,
2
[D8]THF, 190 K): d 46.8 (t, JP,P = 152 Hz, 1P, PPh), –22.2 (d,
2JP,P = 152 Hz, 2P, PMe) ppm. C28H35NiP3S (554.7): Calc.: C, 60.63,
H, 6.36; P, 16.75; S, 5.78. Found: C, 60.13, H, 6.95; P, 16.81%.
3.5. Hydrido(2-diphenylphosphanyl)thiophenolato[P,S]-1,3-
bis[(diphenylphosphanyl)-propane]nickel (3) [25]
1H, 13C and 31P NMR spectra were obtained from Bruker
AVANCE 500, ARX 300 and AM 200 spectrometers. 13C and 31P
NMR resonances were obtained with broad-band proton decou-
pling. Assignment of 13C signals was supported by DEPT trace.
Melting points were measured in capillaries sealed under argon
and are uncorrected.
Ni(PMe3)4 (840 mg, 2.31 mmol) in THF (60 mL) containing
880 mg of trimethylphosphane was combined with (2-diphenyl-
phosphanyl)thiophenol (670 mg, 2.30 mmol) and stirred for
5 min. 1,3-Bis(diphenylphosphanyl)propane (950 mg, 2.30 mmol)
in THF (30 mL) was added, and the volatiles were removed in va-
cuo. The orange residue was washed with two 20 mL portions of
pentane and dried in vacuo. Yield 1.57 g (89%); decomp. >91 °C.
IR (Nujol)
m
= 1910 cmꢀ1 (NiH). 1H NMR (200 MHz, [D8]THF,
3.2. (3-Diphenylphosphanyl)2-thionaphthol
296 K): d 7.65–6.61 (m, 34H, CH), 2.62–0.94 (m, 6H, CH2), –16.9
2-Thionaphthol (20 g, 125 mmol) in 200 mL of TMEDA/cyclo-
hexane (1:1) was dilithiated [10] using nBuLi (2.5 M) (249 mL,
624 mmol) at 25 °C. After cooling to 0 °C chlorodiphenylphosphane
(22.4 mL, 125 mmol) in cyclohexane (50 mL) was added dropwise
under stirring within 1 h. After 16 h at 25 °C the mixture was
hydrolised with water (30 mL), and toluene (200 mL) was added.
The organic layer was washed with three portions (200 mL) of ace-
tic acid (5%). After phase separation the volatiles were removed in
vacuo and the residue was dissolved in warm ethanol (60 mL). Pale
yellow microcrystals were formed that were isolated by filtration
10
S
4
1
2
5
9
9
8
P
7
3
6
2
5
Scheme 1. Assignment of aromatic 13C signals in 1, 3 and 4.

1874
P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
(dt, 2JP,H = 59 and 22 Hz, 1H, NiH) ppm. 31P NMR (81 MHz, [D8]THF,
243 K): d 61.9 (t, JP,P = 74 Hz, 1P, PPh), –14.2 (d, JP,P = 74 Hz, 2P,
PCH2) ppm. C45H41NiP3S (765.5): Calc.: C, 70.61; H, 5.40; P,
12.14. Found: C, 70.64; H, 5.99; P, 11.70%.
3.9. Methyl(3-diphenylphosphanyl)-2-
thionaphtholato[P,S](trimethylphosphane)nickel (7)
2
2
700 mg (3.88 mmol) of NiMe(OMe)(PMe3) in THF were com-
bined with 1.31 g (3.80 mmol) of (3-diphenylphosphino)-2-thio-
naphthol. After 10 min. the volatiles were removed in vacuo and
the residue was extracted with pentane. Crystallization at room
temperature afforded 880 mg of methylnickel complex 7 as orange
prismatic rods. Yield: 44%. m.p. 139–142 °C. IR (Nujol)
3.6. Methyl(2-diphenylphosphanyl)thiophenolato[P,S](trimethylphos-
phane)nickel (4) [25]
NiMe(OMe)(PMe3) (1.35 g, 7.40 mmol) in THF (50 mL) was
combined with (2-diphenylphosphanyl)thiophenol (2.14 g,
7.30 mmol) in THF (30 mL). After stirring for 10 min the volatiles
were evaporated and the residue was extracted with two 50 mL
portions of pentane over a glass-sinter disc (G3). Crystallisation
afforded orange prisms of 4. Yield 1.77 g (54%); m.p. 117–119 °C,
m
= 1219 cmꢀ1(dNiCH3). 1H NMR (500 MHz, [D8]THF, 190 K): d
7.60–7.52 (m, 4H, CH); 7.39 – 7.31 (m, 9H, CH); 7.28–7.26 (m,
2H, CH); 7.19 (m, 1H, CH); 1.08 (s(br), 9H, PCH3); –0.29 (d,
3JP,H = 10.5 Hz, 3H, NiCH3) ppm. 31P NMR (202 MHz, [D8]THF,
2
193 K):
d
50.02 (d, JP,H = 31.4 Hz, 1P, PPh2); –22.7 (d,
decomp. >125 °C. IR (Nujol)
m
= 1183 cmꢀ1(dNiCH3). 1H NMR
2JPMe,PPh = 46.9 Hz, 1P, PCH3) ppm. C26H28NiP2S (493.2): Calc.: C,
63.31; H, 5.72; P, 12.56; S, 6.50. Found: C, 63.69; H, 5.31; P,
11.67; S, 6.77%.
(200 MHz, [D8]THF, 223 K): d 7.60–6.71 (m, 14H, CH), 1.35 d,
3
2JP,H = 8.5 Hz, 9 H, PCH3), –0.37 (d,d JP,H = 9.4 and 8.5 Hz, 3H,
NiCH3) ppm. 13C NMR (125 MHz, [D8]THF, 300 K): d 161.3 (d,
1
2JP,C = 39.0 Hz, C1), 136.8 (d, JP,C = 55.3 Hz, C2), 134.1 (d,
3.10. (2-Diphenylphosphanyl)thiophenolato[P,S]bis(trimeth-
ylphosphane)nickel (8)
3JP,C = 10.1 Hz, C4), 133.7 (s, C3), 132.6 (s, CH5), 131.1 (s, CH6),
3
130.7 (s, CH7), 129.8 (d, JP,C = 12.6 Hz, CH8), 129.1 (d,
3
2JP,C = 10.1 Hz, CH9), 121.4 (d, JP,C = 5.0 Hz, CH10), 13.3 (d,
3.10.1. Method a
2
1JP,C = 26.4 Hz, PCH3), –7.6 (d, JP,C = 22.6 Hz, NiCH3) ppm. 31P
Ni(PMe3)4 (1.50 g, 4.10 mmol) in diethyl ether (50 mL) contain-
ing 1.0 g of trimethylphosphane was combined with (2-diphenyl-
phosphanyl)thiophenol (1.22 g, 4.10 mmol) and stirred for 60 min
at –50 °C. The resulting red solution was filtered at –50 °C. Then
it was carefully warmed to –10 °C and kept at this temperature
for 2 h. Warming was accompanied by evolving gaseous dihydro-
gen and forming a small amount of green thinly dispersed precip-
itate. During this the solution slightly changed its colour keeping
within red gamut. The solution was filtered at –10 °C, and cooling
to –27 °C gave red crystals of 8. Yield 250 mg (12%). Decomp. 42–
2
NMR (81 MHz, [D8]THF, 203 K): d 62.6 (d, JP,P = 301 Hz, 1P, PPh),
2
–1.3 (d, JP,P = 301 Hz, 1P, PCH2) ppm. C22H26NiP2S (443.2): Calc.:
C, 59.63; H, 5.91; P, 13.98. Found: C, 59.68; H, 5.80; P, 13.91%.
3.7. Methyl(2-diphenylphosphanyl)thiophenolato[P,S]bis(trimethyl-
phosphane)nickel(5) [25]
NiMe2(PMe3)3 (1.20 g, 3.70 mmol) in diethyl ether (50 mL) was
combined with (2-diphenylphosphanyl)thiophenol (1.07 g,
3.66 mmol) in diethyl ether (50 mL) and stirred for 15 min. The
volatiles were evaporated and the residue was extracted with
50 mL of pentane containing 0.5 g of trimethylphosphane, and
the red solution was kept at –27 °C to yield dark red needles of
5. Yield 1.29 g (67%); m.p. 118–123 °C, decomp. >132 °C. IR (Nujol)
47 °C. IR (Nujol)
m (qPCH3). MS (70 eV): m/z (%) = 58(4),
= 934 cmꢀ1
77(3), 109(5), 183(17.2), 215(24.5), 293(59), 337(20.4), 369(37),
428(2), 644(100). MS of Ni(P^pS)2 (70 eV): m/z (%) = 58(3.3),
77(3.3), 107(5.8), 152(10), 183(72.5), 215(26.6), 243(7.5),
293(32.5), 337(5.8), 369(17.5), 428(5), 644 (100). EPR (X-Band,
m
= 1158 cmꢀ1(dNiCH3). 1H NMR (500 MHz, [D8]THF, 297 K): d
T = 77 K) g = 2.008, g\ = 2.140, A (1P) = 45 G, A\ (1P) 6 23 G, A
k
k
k
2
7.55–6.69 (m, 14H, CH), 1.13 (d, JP,H = 6 Hz, 18H, PCH3), –0.33 (d,
(2P) = 67 G, A\ (2P) = 57 G.
3JP,H = 9 Hz, 3H, NiCH3) ppm. 13C NMR (75 MHz, [D8]THF, 297 K):
2
1
d 159.5 (d, JP,C = 41.5 Hz, C1), 135.4 (d, JP,C = 52.3 Hz, C2), 133.1
1
3
3.10.2. Method b
(d, JP,C = 36.7 Hz, C3), 132.7 (d, JP,C = 6.3 Hz, CH4), 132.1 (d,
3JP,C = 11.5 Hz, CH5), 130.9 (s, CH6), 129.5 (s, CH7), 128.7 (s,
Complex 8 was prepared in situ by photochemical reduction of
5 in an EPR ampoule. Complex 5 (50 mg) in 1.5 mL of toluene was
sealed in an EPR ampoule which was irradiated by light of wave-
lengths 20000–24000 cmꢀ1 with the EPR signal intensity being
measured every 2 h. After 8 h the intensity reached its maximum.
The resulting solution was deep red, attempts to crystallise the
product failed.
2
4
CH8), 127.8 (d, JP,C = 13.0 Hz, CH9), 119.3 (d, JP,C = 4.6 Hz, CH10),
1
2
13.3 (d, JP,C = 9.3 Hz, PCH3), ꢀ8.3 (d, JP,C = 21.5 Hz, NiCH3) ppm.
31P NMR (81 MHz, [D8]THF, 193 K): d 45.8 (t, JP,P = 179 Hz, 1P,
2
2
PPh), –17.3 (d, JP,P = 179 Hz, 2P, PCH3) ppm. C25H35NiP3S (519.2):
Calc.: C, 57.83; H, 6.79; P, 17.90. Found: C, 57.68; H, 6.83; P, 17.86%.
3.8. Methyl(3-diphenylphosphanyl)-2-
thionaphtholato[P,S]bis(trimethylphosphane)nickel (6)
3.10.3. Method c
Ni(PMe3)4 (1.50 g, 4.10 mmol) in THF (50 mL) containing 1.0 g
of trimethylphosphane was combined with Ni(P^pS)2 (2.7 g,
4.10 mmol) and stirred for 3 h at –10 °C. The volatiles were evapo-
rated, and the residue was extracted with 30 mL of diethyl ether
containing 0.5 g of trimethylphosphane. The red solution at
–27 °C gave red crystals of 8 (IR, EPR). Yield 270 mg (12%).
NiMe2(PMe3)3 (720 mg, 2.30 mmol) in THF (30 mL) at –30 °C
was combined with (3-diphenylphosphanyl)-2-thionaphthol
(790 mg, 2.30 mmol) in THF (30 mL) and stirred for 15 min at
20 °C. The volatiles were evaporated and the residue was extracted
with 80 mL of pentane containing 0.6 g of trimethylphosphane,
and the red solution was kept at –27 °C to yield dark red plates
of 6. Yield 890 mg (59%); m.p. 101–103 °C. IR (Nujol)
m
= 1157 cmꢀ1 (dNiCH3). 1H NMR (500 MHz, [D8]THF, 190 K):
3.10.4. Method d
2
Complex 1 (500 mg, 1 mmol) was dissolved in diethyl ether
(20 mL) containing 300 mg of trimethylphosphane at –10 °C. The
solution was kept at –10 °C for 2 h and then filtered. The red filtrate
was cooled to –27 °C to give red crystals of 8 (IR, EPR). Yield
300 mg (60%).
d = 7.8–7.2 (m, 16H, CH), 1.10 (d, JP,H = 7 Hz, 18H, PCH3), –0.20
(d, JP,H = 10 Hz, 3H, NiCH3) ppm. 31P NMR (202 MHz, [D8]THF,
3
193 K): d 36.9 (s(br), 1P, PPh), –25.3 (s(br), 2P, PCH3) ppm.
C29H37NiP3S (569.3): Calc.: C, 61.18; H, 6.55; P, 16.34; S, 5.64.
Found: C, 60.63; H, 6.47; P, 17.09; S, 4.98%.

P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
1875
3.11. Crystal structure analyses
tals were kept under paraffin oil for protection against humidity.
For single crystal data collection the crystals were placed in pre-
mounted Cryoloops from Hampton Research and cooled down to
100 K, covered with a protecting oil film. Data collection was per-
formed using an Xcalibur diffractometer from Oxford Diffraction,
equipped with the Enhance source option and Sapphire CCD detec-
Crystal data are presented in Tables 1 and 2. Data collection:
Complex 1: A crystal was sealed under argon in a glass capillary
and mounted on an Oxford Xcalibur diffractometer. Reflections
were measured using graphite-monochromated Mo K
a radiation;
Lp correction and absorption correction based on -scans were
W
tor in u and x-scan mode, respectively. The structure was solved
applied. The structure was solved by direct and conventional Fou-
rier methods. All non-hydrogen atoms were treated with a riding
model in idealized positions. Complexes 5, 6 and 7: Selected crys-
by direct methods using SHELXS und refined using SHELXL-97. H atoms
were added at idealized positions. Complex 8: A crystal of 8 was
mounted on a glass capillary with silicone grease, quickly put into
the cold nitrogen stream of the cooling device of the goniometer
and measured on a STOE IPDSII diffractometer. An initial structural
model was obtained by direct methods using SHELXS-97. The remain-
ing atoms were obtained from difference Fourier maps, followed by
least-squares refinement cycles. Refinements were performed
using SHELXL-97. After anisotropic refinement of this model, H atoms
were added at idealized positions.
Table 1
Crystal data for compounds 1 and 8.
1
8
Empirical formula
Formula mass
Crystal size
Crystal system
Space group
a (Å)
C24H33NiP3S
505.18
C24H32NiP3S
504.18
0.50 ꢂ 0.36 ꢂ 0.02
0.36 ꢂ 0.20 ꢂ 0.1
Triclinic
Triclinic
Acknowledgements
ꢁ
ꢁ
P1
P1
9.237(1)
11.775(1)
13.026(1)
71.37(1)
80.02(1)
82.48(1)
1317.9(2)
2
9.098(7)
11.650(9)
12.937(8)
72.533(2)
81.091(3)
82.969(1)
1288.29(3)
2
b (Å)
c (Å)
We are grateful to Prof. J.J. Schneider for providing laboratory
facilities, to Prof. K.-P. Dinse for a generous share of an EPR spec-
trometer, to Prof. W. Haase for magnetic measurements, to Prof.
B. Albert for a part of the crystallography. P.K. thanks DAAD for a
research stipendium, and H.A.B. is grateful for a scholarship of
the Lybian state.
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (g/cm3)
1.237
1.006
1.300
1.03
l(Mo K
a
) (mmꢀ1
)
Appendix A. Supplementary material
Temperature (K)
Data collected range (°)
301(2)
8.3 P 2
150
H
P 52.7
1.9 P 2H P 54.2
h
k
l
ꢀ6 P h P 11
ꢀ14 P k P 14
ꢀ16 P l P 16
8836
5274
293
1.351
0.0404
0.1316
ꢀ11 P h P 11
ꢀ14 P k P 14
ꢀ16 P l P 16
19766
5588 (Rint = 0.0547)
262
1.027
0.0398
0.0931
CCDC 705060, 705061, 705062, 708341 and 705063 contain the
supplementary crystallographic data for complexes 1, 5, 6, 7 and 8.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_re-
quest/cif. Supplementary data associated with this article can be
No. of reflections measured
No. unique data
Parameters
Goodness-of-fit on F2
found,
in
the
online
version,
at
doi:10.1016/
R1 [I P 2
wR2 (all data)
r(I)
j.jorganchem.2009.01.023.
References
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Table 2
Crystal data for compounds 5–7.
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5
6
7
Empirical formula C25H35NiP3S
C29H37NiP3S
569.27
C26H28NiP2S
493.19
Formula mass
Crystal size (mm)
Crystal system
Space group
a (Å)
519.21
0.40 ꢂ 0.20 ꢂ 0.06 0.16 ꢂ 0.16 ꢂ 0.08 0.32 ꢂ 0.28 ꢂ 0.14
Monoclinic
P21/n
Monoclinic
P21/n
Monoclinic
P21/n
10.465(2)
10.532(2)
24.233(3)
100.66(1)
2624.8(8)
4
13.5939(8)
13.9297(7)
15.0138(8)
94.366(5)
2834.7(3)
4
1.334
0.944
100(2)
4.9 P 2
9.0995(6)
12.8266(4)
20.6562(6)
96.155(4)
2397.00(19)
4
1.367
1.041
100(2)
4.72 P 2H P 52.72
b (Å)
c (Å)
b (°)
V (Å3)
Z
Dcalc (g/cm3)
1.314
l(Mo K
a
) (mmꢀ1) 1.012
Temperature (K)
Data collected
range (°)
h
k
l
No. reflections
measured
No. unique data
100(2)
4.6 P 2
H
P 52.4
H
P 52.7
ꢀ11 P h P 13
ꢀ12 P k P 13
ꢀ30 P l P 27
21543
ꢀ15 P h P 16
ꢀ17 P k P 17
ꢀ18 P l P 18
23007
ꢀ11 P h P 11
ꢀ15 P k P 16
ꢀ25 P l P 25
20568
5350
(Rint = 0.0561)
278
5783
(Rint = 0.0943)
313
4899 (Rint = 0.0943)
Parameters
Goodness-of-fit
on F2
275
1.049
1.040
1.097
R1 [I P 2r(I)]
0.0502
0.0987
0.0684
0.1206
0.0355
0.1039
wR2 (all data)

1876
P.B. Kraikivskii et al. / Journal of Organometallic Chemistry 694 (2009) 1869–1876
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