Transformations of aryl isothiocyanates on tetraphosphine tungsten complexes and reactivity of the resulting dithiocarbonimidate ligand

Article abstract of DOI:10.1039/c1dt11201e

Treatment of [WH₄(κ⁴-P4)] (3: P4 = meso-o-C₆H₄(PPhCH₂CH₂PPh ₂)₂) with aryl isothiocyanate ArNCS at 50 °C afforded the dithiocarbonimidate-isocyanide complex [W(κ²-S ₂CNAr)(CNAr)(κ⁴-P4)] (4) in moderate yields. The reaction also produced ArNHCH₃ and a small amount of ArNH ₂. The yield of the hydrodesulfurization product ArNHCH₃ increased when the reaction was conducted under H₂ (up to 0.65 equiv. to 3 for Ar = p-MeC₆H₄ (Tol)). Complex 4 was proposed to be formed via reductive disproportionation of two ArNCS molecules on a zero-valent W species generated by dissociation of H₂ from 3. The reaction of W(0) complex [W(dppe)(κ⁴-P4)] (dppe = Ph ₂PCH₂CH₂PPh₂) with ArNCS also yielded 4 accompanied by free dppe, in contrast to that of [Mo(dppe) (κ⁴-P4)], which had been previously reported to undergo sulfur-atom transfer to phosphine ligands. The dithiocarbonimidate ligands in 4a (Ar = Tol) received the addition of electrophiles [PhMe₂NH][BF ₄], MeI, and PhCOCl selectively at the N atom to afford the cationic dithiocarbamate complexes [W(κ²-S₂CNHTol)(CNTol) (κ⁴-P4)][BF₄] (6), [W{κ²-S ₂CN(Me)Tol}(CNTol)(κ⁴-P4)]I (7), and [W{κ²-S₂CN(COPh)Tol}(CNTol)(κ⁴-P4)] Cl (8). Complexes 4a, 6, 7, and 8 have been characterized by spectroscopic and crystallographic methods, and the donor strengths of their κ²- dithio ligands are discussed. The Royal Society of Chemistry 2011.

Full text of DOI:10.1039/c1dt11201e

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PAPER
Transformations of aryl isothiocyanates on tetraphosphine tungsten
complexes and reactivity of the resulting dithiocarbonimidate ligand†
Qi Xiu Dai, Hidetake Seino* and Yasushi Mizobe*
Received 24th June 2011, Accepted 18th August 2011
DOI: 10.1039/c1dt11201e
4
Treatment of [WH4(k -P4)] (3: P4 = meso-o-C6H4(PPhCH2CH2PPh2)2) with aryl isothiocyanate ArNCS
◦
2
4
at 50 C afforded the dithiocarbonimidate-isocyanide complex [W(k -S2CNAr)(CNAr)(k -P4)] (4) in
moderate yields. The reaction also produced ArNHCH3 and a small amount of ArNH2. The yield of
the hydrodesulfurization product ArNHCH3 increased when the reaction was conducted under H2 (up
to 0.65 equiv. to 3 for Ar = p-MeC6H4 (Tol)). Complex 4 was proposed to be formed via reductive
disproportionation of two ArNCS molecules on a zero-valent W species generated by dissociation of
4
H2 from 3. The reaction of W(0) complex [W(dppe)(k -P4)] (dppe = Ph2PCH2CH2PPh2) with ArNCS
also yielded 4 accompanied by free dppe, in contrast to that of [Mo(dppe)(k -P4)], which had been
4
previously reported to undergo sulfur-atom transfer to phosphine ligands. The dithiocarbonimidate
ligands in 4a (Ar = Tol) received the addition of electrophiles [PhMe2NH][BF4], MeI, and PhCOCl
2
selectively at the N atom to afford the cationic dithiocarbamate complexes [W(k -S2CNHTol)(CNTol)-
4
2
4
2
(k -P4)][BF4] (6), [W{k -S2CN(Me)Tol}(CNTol)(k -P4)]I (7), and [W{k -S2CN(COPh)Tol}(CNTol)-
4
(k -P4)]Cl (8). Complexes 4a, 6, 7, and 8 have been characterized by spectroscopic and crystallographic
2
methods, and the donor strengths of their k -dithio ligands are discussed.
groups and a rigid o-phenylene, is distinct from those of the above
Introduction
representative tetraphosphines having alkyl-chain linkages only.
Although the steric bulk and donating ability seem almost com-
parable between P4 and the bis-dppe system, the accumulation of
Stereochemical control of transition metal complexes by multiden-
tate ligands is an effective method for designing new structures,
unique physical properties, and excellent catalytic functions.
Synthesis and coordination chemistry of tetradentate phosphine
ligands have long been studied since the 1960s.1 A wide variety of
such ligands are majorly classified into linear, tripodal, and other
branched types based on structure (cyclic is also known),2 and
among the linear-type tetraphosphines, those of the general for-
mula R2P(CH2)2PR(CH2)nPR(CH2)2PR2 (n = 1, 2, 3, etc.) are well
known.3–5 We have been investigating the group 6 metal complexes
with a tetraphosphine ligand meso-o-C6H4(PPhCH2CH2PPh2)2
(abbreviated as P4 in this report), which is easily obtained as
4
chelate-ring strains in the k -coordination of P4 makes drastic
divergences from the chemistry of bis-dppe complexes.7 Our
previous studies on Mo and W complexes have revealed structures
and reactivity specific to P4, and recently the tetrahydride complex
4
[WH4(k -P4)] (3) has been synthesized.8 The structure of 3 is
different from the analogous complex [WH4(dppe)2] in some
points, and moreover, the reactivity of 3 is much higher than
[WH4(dppe)2], probably owing to a highly strained geometry
around the W centre and the ability of P4 to change hapticity.9
Subsequent study on the reactions of 3 with CS2 and RNC
4
2
(R = But, 2,6-Me2C6H3) has resulted in isolation of [W(k -
the complex form [M(dppe)(k -P4)] (M = Mo (1), W (2); dppe =
Ph2PCH2CH2PPh2) by heating trans-[M(N2)2(dppe)2] with dppe.6
Via an unconventional bond recombination in the coordination
sphere, two dppe ligands are converted into P4 and an equimolar
benzene under excellent stereocontrol of meso, in spite of the
possible existence of the rac-diastereomer. The unique structure
of P4, in which four P atoms are linked by two flexible ethylene
4
4
S2CH2)(k -P4)] and [W(CNR)2(k -P4)], proving that 3 is not only
a strong hydride donor but also a good precursor of coordinatively
unsaturated species. Such a dual reactivity is generally known for
polyhydride complexes of transition metals,10 and specific bond
formation and cleavage has been performed on the low-valent
intermediates generated by reductive elimination of H2.
Now we have extended our study on 3 to reactivity toward aryl
isothiocyanates11 and discovered diverse reaction pathways. Zero-
valent complex 2 and analogous W(dppe)2 complexes have also
been examined to compare reactivity to isothiocyanates, and the
result of the former complex is unexpected from the preceding
work using the Mo congener 1.12 In addition, further conversion
of the major complex product containing a dithio ligand has
Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-
ku, Tokyo 153-8505, Japan. E-mail: seino@iis.u-tokyo.ac.jp
1
1
† Electronic supplementary information (ESI) available: H and 31P{ H}
NMR spectra of all new complexes. CCDC reference numbers 831904–
831908. For ESI and crystallographic data in CIF or other electronic
format see DOI: 10.1039/c1dt11201e
11822 | Dalton Trans., 2011, 40, 11822–11830
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Scheme 1
revealed that double hydride insertion takes place in the reaction
been carried out, and structural and spectroscopic properties are
discussed.
2
4
of 3 with a related heterocumulene CS2 to give [W(k -S2CH2)(k -
P4)].8 Although the result of the reaction with ArNCS appears
contrasting, a mechanism involving the corresponding complex
Results and discussion
2
4
[W(k -SCH2NAr)(k -P4)] is postulated (Scheme 2). This interme-
diary complex may react directly with H2 to liberate ArNHCH3
or degrade into ArN CH2, which then undergoes hydrogenation.
Any reaction did not take place at lower temperature, and inter-
mediate complexes could not be observed. Attempts to identify
the W species produced together with ArNHCH3 and ArNH2
were unsuccessful, but complexes other than 4 were detected in
the liquid phase by NMR measurement. Complex 4 is probably
formed via a different pathway, as discussed later. It has been
reported that two mols of Cp2ZrHCl react with RNCS (R = aryl
or alkyl) to form [Cp2ZrCl]2(m-S) concomitantly with RN CH2
and a very small amount of RNHCH3.13d Complex 3 reacted with
alkyl isothiocyanates in different ways, and the products could not
be identified.
1. Reaction of [WH4(j4-P4)] with ArNCS
Heating a toluene solution of 3 with 3 equiv. of ArNCS (Ar = p-
MeC6H4 (Tol), Ph, p-ClC6H4) at 50 ◦C resulted in the precipitation
of a brown solid, which was identified as dithiocarbonimidate-
2
4
isocyanide complex [W(k -S2CNAr)(CNAr)(k -P4)] (4) (Scheme
1). Characterization of the new complex 4 is discussed in the next
section. The yields of 4 were 32–45% when the reactions were
carried out under N2 atmosphere, and they slightly increased to
34–60% under H2 atmosphere.
GLC analyses revealed that the liquid phase of these reactions
contained ArNHCH3, ArNH2, and unreacted ArNCS as shown
in Table 1. The majorly formed ArNHCH3 is regarded as the
hydrodesulfurization product from ArNCS, and its yield based
on 3 varied from 12% for Ar = p-ClC6H4 to 45% for Ar =
Tol. The yields also depended on the reaction atmosphere, and
in comparison with the above results under N2, they increased
by about 0.5 times under H2 (up to 67% on 3 for Ar = Tol).
Amounts of the other product ArNH2 are small, and dependence
on Ar group or reaction atmosphere is of no significance for
discussion. It is unclear whether ArNH2 have been formed via
hydrogenation or hydrolysis by a trace of moisture. Formation of
these compounds was not catalytic, because amounts of organic
products and unreacted ArNCS almost reached convergence at
initial 8 h. This fact also confirms that either ArNHCH3 or ArNH2
is not formed via 4 as the intermediate.
Scheme 2
Insertion of RNCS into a metal-H bond has been demonstrated
for many transition metal complexes.13 It has been previously
2. Characterization of complex [W(j2-S2CNAr)(CNAr)(j4-P4)]
Table 1 Amounts of organic compounds (equiv. to W) in the reactions
of 3 with ArNCS; the conditions are shown in Scheme 1
The molecular structure of 4a (Ar = Tol) has been fully determined
by single-crystal X-ray crystallographic analysis. An ORTEP
drawing is shown in Fig. 1 and selected bond distances and angles
are collected in Table 2. The geometry of the metal centre is a
highly distorted pentagonal bipyramid, in which the isocyanide
ligand and one of the sulfur atoms of the dithiocarbonimidate
ligand are occupying axial positions with the S–W–C angle at
173.69(8)◦. The equatorial plane consists of the other S atom
and four P atoms of the tetracoordinated P4. The acute S–W–S
Reaction
atmosphere
Consumed
ArNCS
Ar
ArNHCH3
ArNH2
Tol
N2
H2
N2
H2
N2
H2
2.19
1.76
2.52
2.23
2.07
2.16
0.45
0.67
0.23
0.33
0.12
0.21
0.11
0.15
0.07
0.11
0.08
0.14
Ph
p-ClC6H4
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1
The 31P{ H} NMR spectrum of 4a in CDCl3 solution at
20 ◦C showed two very broad peaks centred at d 46 and 66,
corresponding to the outer and inner P atoms, respectively. The
spectrum changed at -50 ◦C into two pairs of signals, the major set
of which was observed at d 49.9 and 66.9, while the minor appeared
at d 47.4 and 67.3 in a intensity ratio of major/minor = 7/3. Low
Table 2 Selected bonding parameters and IR data for 4a, 6, 7, and 8
4a
6
7
8
˚
Bond distance /A
W–S(1)
W–S(2)
S(1)–C(47)
S(2)–C(47)
C(47)–N(1)
N(1)–C(48)
W–C(55)
2.5474(7) 2.5282(10)
2.5553(7) 2.5541(7)
1.740(3) 1.704(3)
1.777(3) 1.715(4)
1.282(3) 1.335(5)
1.418(4) 1.426(4)
1.947(2) 1.975(3)
1.231(3) 1.196(5)
1.394(3) 1.404(4)
2.5544(13) 2.5361(10)
2.5444(16) 2.5057(10)
1.694(7)
1.726(5)
1.338(8)
1.680(3)
1.704(3)
1.409(5)
temperature H NMR (-50 ◦C) also supported the presence of
1
two species in the above ratio, and the spectra around 20 ◦C
were also broadened severely. These observations are explained
by the syn/anti-isomerism of the dithiocarbonimidate ligand with
respect to the C N bond (Chart 1), whose dynamic exchange
causes broadening of NMR signals.18 Structure I is found in the
crystal as mentioned above, and the other conformation II is
probably equilibrating with I in solution. In contrast to 4a, the
supplementary single-crystal X-ray study of 4c (Ar = p-ClC6H4)
has revealed the structure corresponding to II, in which the Ar
group is directed to the axial S(1) atom as shown in Fig. 2. This
and 4b exhibit NMR spectra similar to 4a.
1.438(12) 1.446(5)
1.943(5)
1.229(6)
1.403(7)
1.967(3)
1.198(5)
1.396(4)
C(55)–N(2)
N(2)–C(56)
Bond angle/◦
S(1)–W–S(2)
W–S(1)–C(47)
W–S(2)–C(47)
S(1)–C(47)–S(2)
S(1)–C(47)–N(1)
S(2)–C(47)–N(1)
C(47)–N(1)–C(48)
W–C(55)–N(2)
C(55)–N(2)–C(56)
IR (KBr)/cm-1
68.68(2) 68.22(2)
91.18(9) 89.96(14)
90.08(10) 88.85(11)
109.85(15) 112.9(2)
121.8(2) 120.1(2)
128.3(2) 127.0(2)
121.7(2) 127.2(3)
174.7(2) 177.3(3)
140.2(2) 143.7(3)
67.79(4)
90.02(19) 89.13(13)
89.6(2)
112.5(3)
123.1(4)
124.3(5)
122.2(5)
174.4(4)
143.2(5)
68.12(3)
89.60(13)
113.1(2)
128.4(2)
118.5(2)
115.5(3)
175.4(3)
162.2(4)
n(C N) or n(C–N)a 1512
n(C N) 1773
1361
1374
1199, 1257b
1930
1804, 1887sh 1887
a Dithiocarbonimidate or dithiocarbamate ligand. b Discrimination from
the n(C–N) of the amide group is impossible.
Chart 1
Fig. 1 The molecular structure of 4a showing thermal ellipsoids at 50%
probability. Hydrogen atoms and the phenyl carbons except the ipso
positions are omitted for clarity.
angle at 68.68(2)◦ makes the equatorial S(2) atom deviate from the
pentagonal plane toward the axial S(1) atom. The P(4) atom is also
out of the equatorial plane to the side of the isocyanide ligand. The
two C–S distances are comparable to those of dithiocarbonimidate
complexes possessing an N-aryl or N-alkyl group.14,15 The C(47)–
Fig. 2 The molecular structure of 4c showing thermal ellipsoids at 50%
probability. Hydrogen atoms and the phenyl carbons except the ipso
positions are omitted for clarity.
˚
N(1) bond length of 1.282(3) A is typical for a C–N double bond,
while the IR absorption at 1512 cm-1 for n(C N) is at a relatively
low frequency among analogous complexes.14 The C(47)–N(1)–
C(48) linkage is co-planar to the WS2C ring and bent at 121.7(2)◦.
The Tol group is directed cis to S(2), and this aromatic ring and the
S2CN plane are twisted with respect to each other with the dihedral
angle of 64◦. For the isocyanide ligand, the relatively long C(55)–
N(2) bond and a large deviation from linearity of the C(55)–N(2)–
C(56) linkage indicate strong back-donation from the W centre,
which is also reflected in the very low frequency of n(C N) in the
IR spectrum (1773 cm-1). Such bent structures are often observed
for alkyl isocyanides but rarely for aryl isocyanides.16,17
3. Mechanisms forming [W(j2-S2CNAr)(CNAr)(j4-P4)]
A reaction pathway different from that producing ArNHCH3 is
proposed for the formation of 4. A formal W(0) species is probably
generated by the liberation of H2 from 3 and promotes the reduc-
tive disproportionation of two ArNCS molecules into dithiocar-
bonimidate and isocyanide ligands. Such bond recombinations of
RNCS have been known mostly for group 8–10 metal complexes in
low oxidation states. Complexes of the type [M(S2CNR)(CNR)Ln]
have been obtained selectively by the reactions of Ru(0)19 Rh(I),19,20
11824 | Dalton Trans., 2011, 40, 11822–11830
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and Pt(0)21 complexes. In the cases of Pd(0), Pt(0) and their
precursors, the concomitantly formed isocyanide dissociated from
the metal to result in dithiocarbonimidate complexes.14g,h,15b,21,22
These types of reactions have been reported for Mn(-I), Re(-I), and
Mo(0,I), although the dithiocarbamate complexes are provided via
the following N-protonation.23 Conversion of RNCS into RNC
proceeds on some complexes including W(II) and Mo(0), where
the sulfur atom is accepted by the metal or its fate is unknown.24,25
E. Carmona and co-workers have reported that the zero-valent
molybdenum and tungsten complexes trans-[M(C2H4)2(PMe3)4]
with TolNCS and PhNCS to form 4a and 4b required a higher
temperature (80 ◦C). Reactivity of the complexes having bis-
dppe co-ligands was also tested by using trans-[W(N2)2(dppe)2],
which readily generates coordinatively unsaturated W(0) species.
However, treatment with ArNCS at 80 ◦C resulted not in the
formation of an analogue of 4, but in decomposition giving
sulfides of dppe.29 Stereocontrol of coordination geometry by
P4 may play an important role in providing a wide reaction site
that allows association of two ArNCS molecules and in driving
a severely distorted octahedral intermediate into the relatively
stable pentagonal bipyramidal structure. It is also noticeable that
the reaction of the Mo complex 1 with ArNCS under similar
conditions affords entirely different products, 5 and a monosulfide
of dppe (Scheme 4).12 As many as three TolNCS molecules react
with 1, two of which are converted into TolNC by desulfurization
(M
= Mo, W) react with PhNCS or CS2 to form
[M(S2C2X2)(C2H4)n(PMe3)4-n] (n = 1, 2; X = NPh, S), whose
structures for X = NPh have been proposed as in Chart 2 based on
the single-crystal X-ray crystallography for X = S.26 Similar metal-
lacyclic structures are generated in the reactions of [RhCl(PPh3)3]27
and [CpCo(PMe3)2]28 with certain isothiocyanates, and postulated
as the intermediate of metal-mediated disproportionation of two
isothiocyanate molecules. Formation of 4 probably proceeds via
the analogous complex that is produced by dimerization of ArNCS
in the coordination sphere, and subsequent deinsertion of ArNC
as illustrated in Scheme 3.
2
and the remaining TolNCS binds to the Mo centre in an h manner
at the C S bond. With respect to the S abstraction from TolNCS,
one abstracted S atom moves to the terminal P atom in P4 to
give a dangling P( S)Ph2 moiety and the other one is trapped by
dppe. It is presumed that the electron-donating ability of the W(0)
centre is high enough to promote the reductive disproportionation
of ArNCS, while sulfur atom transfer to tertiary phosphines28,30
proceeds on the less-donating Mo(0) centre.
4. Reactions of dithiocarbonimidate ligand with electrophiles
Dithiocarbonimidate ligands are commonly known to un-
dergo addition of electrophiles such as proton and methylating
agents.14a,e,19,21,23a,31 Electrophilic attack mostly takes place at the
N atom to give a dithiocarbamate ligand, while a few examples
of S-methylation have been reported.23a,31c High nucleophilicity of
the dithiocarbonimidate ligand in 4 is expected, but at the same
time the isocyanide ligand, which is activated by extremely strong
back-donation, probably has electrophilicity at its N atom.32 In
practice, 4a reacted with various electrophiles selectively at the
N atom of the dithiocarbonimidate ligand. Treatment of 4a with
[PhMe2NH][BF4], MeI, and PhCOCl afforded the cationic dithio-
Chart 2
2
4
carbamate complexes [W(k -S2CNHTol)(CNTol)(k -P4)][BF4]
2
4
2
(6), [W{k -S2CN(Me)Tol}(CNTol)(k -P4)]I (7), and [W{k -
4
Scheme 3
S2CN(COPh)Tol}(CNTol)(k -P4)]Cl (8) in 71–85% yields through
N-protonation, N-methylation, and N-benzoylation (Scheme 5).
The structures of 6, 7, and 8 have been fully determined by
single-crystal X-ray analysis. The ORTEP drawings are shown in
Fig. 3–5, and selected bond lengths and angles are listed in Table
2. The coordination geometries of 6–8 are essentially identical
to that of 4a. A number of seven-coordinate W(II) complexes
having dithiocarbamate ligands have been crystallographically
Based on speculation that a W(0) intermediate is the key to the
formation of 4, reactivity of the zero-valent complex 2 toward aryl
isothiocyanates was examined. As expected, treatment of 2 with
3 equiv. of p-ClC6H4NCS in toluene at 50 ◦C gave 4c accompanied
by free dppe (Scheme 4). It was proved that 2 was less reactive than
3 toward ArNCS, which is not electron-deficient, and reactions
Scheme 4
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Scheme 5
Fig. 3 The molecular structure of the cationic part of 6 showing thermal
ellipsoids at 50% probability. The Et2O molecule interacting through
hydrogen bonding is also shown. Hydrogen atoms except the NH group
and the phenyl carbons other than the ipso positions are omitted for clarity.
Fig. 4 The molecular structure of the cationic part of 7 showing thermal
ellipsoids at 50% probability. Hydrogen atoms and the phenyl carbons
except the ipso positions are omitted for clarity. Selected bond lengths
(A) and angles ( ): N(1)–C(63), 1.483(9); C(47)–N(1)–C(63), 118.0(6);
C(48)–N(1)–C(63), 119.8(6).
determined33 and the bonding parameters of 6–8 are compatible
with these regarding the k -dithio ligands. For all the dithiocar-
◦
˚
2
bamate ligands determined here, the geometry around the C(47)–
N(1) bond is essentially planar, and the Tol group is oriented syn
to the equatorial S similarly to 4a. Nonetheless, small distortions
due to steric repulsion and packing effects are observed for 7
and 8, where the dihedral angles between the trigonal planes
around the C(47) and N(1) are 11◦ and 20◦, respectively. For 8, the
corresponding twist along the N(1)–C(63) axis is 10◦, and the tilt
of the Tol and the Ph rings is much larger (69◦ along N(1)–C(48)
and 48◦ along C(63)–C(64)). In accordance with the structural
differences as illustrated in Chart 3, the C–S bonds are shorter and
S2C–N bonds are longer in dithiocarbamate complexes 6–8 than
in the dithiocarbonimidate complex 4a. The C(47)–N(1) distances
elongation is reflected in the low-frequency shift (140–150 cm-1)
of the IR absorption for the C–N stretching mode. The electron-
withdrawing PhCO group further elongates the C(47)–N(1) bond
˚
to 1.409(5) A in 8, as explained by involvement of the resonance
2
III. For comparison, [Mn(CO)3(PMe2Ph)(k -S2CNHCOOEt)] has
the C–S bonds of 1.678(3) and 1.704(3) A and the S2C–N length
˚
34
˚
at 1.363(4) A.
The extent of back-donation to the isocyanide ligand seems
2
compatible to donor strength of the k -dithio ligand, which
decreases in the order 4a > 6, 7 > 8. Although bond distances in the
isocyanide ligands exhibit no significant differences, the bending
of the C–N–C linkage is slightly reduced in 6 and 7 (36.3(3)◦ and
36.8(5)◦ from linearity) as compared with 4a (39.8(2)◦) and that
˚
in 6 and 7 are increased by > 0.05 A in comparison with 4a
owing to the contribution of the resonance structures II. This bond
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NMR study of 7 in CDCl3 at 20 ◦C. Because both 1H and31P signals
were clearly observed, exchange in solution was indicated, which
was as fast as to reach equilibrium within a few minutes but much
slower than the NMR time-scale. There are probably geometrical
isomers 7 and 7¢ present, arisen from the rotation barrier of the
N–CS2 bond. There were no considerable differences between the
NMR signals of 7 and 7¢, and the chemical shifts were comparable
to those of 6. Only one species was observed in the NMR study
of 8, but it is unclear whether the free rotation of the N–C bond
or predominance of one conformer is attributable. The chemical
shift of the outer P atoms for 8 was the most down-field among
the complexes here.
Conclusion
In this study, we have revealed dual reactivity of the tetrahydride
complex 3 bearing a tetraphosphine co-ligand P4. Conversion of
aryl isothiocyanates by 3 proceeds through two different pathways.
One is hydrodesulfurization to give ArNHCH3, and, as far as we
know, such a type of hydrogenation by a well-defined polyhydride
complex is very rare albeit not catalytic. The other is the formation
of a dithiocarbonimidate–isocyanide complex via the alternative
mechanism that two ArNCS molecules undergo reductive dis-
proportionation on a formally W(0) centre. These reactions are
uniquely assisted by the P4 co-ligand and not attainable by other
W and Mo complexes with the related bis-diphosphine ligand
set (e.g. dppe). The resulting dithiocarbonimidate ligand can be
derivatized by the addition of electrophiles, which has provided
a series of N-substituted dithiocarbamate ligands with varied
electronic properties. We will continuously explore the reactivity
of 3 and other P4 complexes toward unsaturated small molecules.
Fig. 5 The molecular structure of the cationic part of 8 showing thermal
ellipsoids at 50% probability. Hydrogen atoms and the phenyl carbons
˚
except the ipso positions are omitted for clarity. Selected bond lengths (A)
and angles (◦): N(1)–C(63), 1.419(5); O(1)–C(63), 1.210(5); C(63)–C(64),
1.504(6); C(47)–N(1)–C(63), 121.1(3); C(48)–N(1)–C(63), 121.9(3).
Experimental
General considerations
All manipulations were carried out by using standard Schlenk
techniques under pure N2 or H2. Solvents were dried by
common methods and distilled under N2 before use. Com-
plexes [W(dppe)(k -P4)]·toluene (2·toluene)6 and [WH4(k -
P4)]·0.5toluene (3·0.5toluene)8 were prepared as described pre-
viously, and other reagents were commercially obtained and used
without further purification. NMR spectra were measured on a
JEOL alpha-400 or a JEOL ECS 400 spectrometer at 20 ◦C, except
those indicated otherwise. Chemical shifts were referred to those
of isotopic impurities for 1H (CD2Cl2 at 5.32 and CDCl3 at 7.26)
4
4
Chart 3
in 8 becomes substantially linear (17.8(4)◦). The same tendency as
the result of the decrease in back bonding is observed also in the
high frequency shift of the n(C N).
In the crystallographic analysis of 6, the hydrogen atom attached
to the N(1) has been found in the Fourier maps, and its existence
is further evidenced by the Et2O molecule at the neighbor, which is
probably acting as a hydrogen-bond acceptor (N ◊ ◊ ◊ O = 2.956(6)
A, H ◊ ◊ ◊ O = 2.10(8) A). Although IR absorption due to the N–H
bond could not be specified, the NH proton was clearly determined
by 1H NMR measurement as a singlet of 1H intensity (d 7.79 in
CDCl3 at 40 ◦C), which disappeared after adding D2O. In contrast
to 4a, the NMR spectra of 6 were well resolved, and attributed to
single species. The appearance of two 31P signals support that the
cation of 6 (also 7 and 8) possesses a mirror symmetry in NMR
criteria. While the chemical shifts of the inner P atoms at lower
field were almost equal between 6 and 4a, the high-field outer P
signal of 6 shifted to down field by > 6 ppm from that of 4a. Unlike
for 6, the presence of two isomers in a 3 : 1 ratio was revealed by the
1
or to external 85% H3PO4 (0 ppm) for 31P. For the H data, the
signals due to P4 are omitted. IR spectra were recorded on a
JASCO FT/IR-420. Elemental analyses were done with a Perkin–
Elmer 2400 series II CHN analyzer. GLC and GC-MS analyses
were performed with a Shimadzu GC-14B gas chromatograph
and a GC-MS QP-5050 spectrometer equipped with a CBP1 or
CBP10 fused silica capillary column (25 m length ¥ 0.25 mm i.d.),
and organic compound were quantitatively determined by using
PhCH2CH2Ph as the internal standard.
˚
˚
Reaction of 3 with TolNCS
A toluene solution (5 mL) of 3·0.5toluene (0.099 g, 0.10 mmol) and
TolNCS (0.046 g, 0.31 mmol) was stirred under N2 atmosphere
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at 50 ◦C for 30 h.
A
brown precipitate of [W(k -
difficult to determine due to severely broad signals; d 46 (vbr,
outer P of the minor), 47 (vbr, outer P of the major), 65 (vbr,
inner P of the major), 66 (vbr, inner P of the minor). IR (KBr,
cm-1): 1511 s (n(C N)), 1742 brvs (n(C N)). Anal. calcd for
C63.5H54Cl2N2P4S2W: C, 59.22; H, 4.23; N, 2.18%. Found C, 59.16;
H, 4.15, N, 2.07%.
Similar reaction of 3·0.5toluene (0.095 g, 0.10 mmol) with p-
ClC6H4NCS (0.051 g, 0.30 mmol) under H2 atmosphere gave
4c·0.5toluene (0.043 g, 34% yield).
2
4
S2CNTol)(CNTol)(k -P4)]·0.5toluene (4a·0.5toluene) was filtered
off and dried under vacuum (0.052 g, 40% yield). The liquid
phase was analyzed by GLC and GC-MS to determine the organic
compounds. Recrystallization of 4a from THF/hexane afforded
brown prismatic crystals of 4a·THF, which were suitable for single-
crystal X-ray diffraction study. 1H NMR (CD2Cl2, 20 ◦C): d 2.20,
2.23 (s, 3H each, C6H4Me), 5.26 (br d, J = 7.2 Hz, NC6H4), 6.37 (br,
2H, NC6H4), 6.65, 6.87 (br d, J = 7.6 Hz, 2H each, NC6H4), 2.34
◦
1
(s, 1.5H, 0.5toluene). H NMR (CDCl3, 20 C): d 2.27 (vbr, 6H,
C6H4Me), 5.16 (vbr, 2H, NC6H4), other signals of NC6H4 groups
appeared as very broad signals in the region of 6.0 - 7.0, 2.36 (s,
1.5H, 0.5toluene). 1H NMR (CDCl3, -50 ◦C): d 2.15, 2.19, 2.25 (br,
total 6H, ca. 0.7 : 1 : 0.3 ratio), 5.14 (br, 2H), 6.24 (br, 1.4H), 6.52
Reaction of 2 with TolNCS
A mixture of 2·toluene (0.130 g, 0.0930 mmol) and TolNCS
(0.049 g, 0.33 mmol) in toluene (5 mL) was stirred under N2
atmosphere at 80 ◦C for 20 h. The resulting brown precipitate was
filtered and dried under vacuum to give 4a·0.5toluene as brown
solid (0.062 g, 53% yield).
1
(br, 0.6H), 6.62 (br, 2H), 6.80 (br, 1.4H). 31P{ H} NMR (CDCl3,
20 ◦C): Existence of two species was observed, although their
ratio was difficult to determine due to severely broad signals; d
1
42–49 (vbr, outer P), 63–69 (vbr, inner P). 31P{ H} NMR (CDCl3,
Reaction of 2 with PhNCS
-50 ◦C): d 47.4 (br, outer P of the minor), 49.9 (br, outer P of the
major), 66.9 (br, inner P of the major), 67.3 (br, inner P of the
minor), major : minor = 7 : 3. IR (KBr, cm-1): 1512 s (n(C N)),
1773 brs (n(C N)). Anal. calcd for C65.5H60N2P4S2W: C, 63.08;
H, 4.85; N, 2.25%. Found C, 62.90; H, 4.75, N, 2.03%.
Similar reaction of 3·0.5toluene (0.101 g, 0.106 mmol) with Tol-
NCS (0.051 g, 0.34 mmol) under H2 atmosphere gave 4a·0.5toluene
(0.057 g, 43% yield).
Similar reaction of 2·toluene (0.137 g, 0.0983 mmol) with PhNCS
◦
(38 mL, 0.32 mmol) in toluene (5 mL) at 80 C for 22 h gave 4b
(0.067 g, 58% yield).
Reaction of 2 with p-ClC6H4NCS
Similar reaction of 2·toluene (0.132 g, 0.0949 mmol) and p-
◦
ClC6H4NCS (0.053 g, 0.31 mmol) at 50 C for 20 h gave brown
solid of 4c·0.5toluene (0.058 g, 47% yield).
Reaction of 3 with PhNCS
Reaction of 4a with [PhMe2NH]BF4
PhNCS (0.044 g, 0.33 mmol) was added into a 5 mL toluene
solution of 3·0.5toluene (0.098 g, 0.10 mmol). After this solution
A CH2Cl2 solution (4 mL) of 4a·0.5toluene (0.098 g, 0.078 mmol)
and [PhMe2NH]BF4 (0.017 g, 0.080 mmol) was stirred under
N2 atmosphere at room temperature for 24 h. Addition of ether
(18 mL) to the concentrated solution (3 mL) formed red crystals
◦
2
was stirred under N2 atmosphere at 50 C for 30 h, [W(k -
4
S2CNPh)(CNPh)(k -P4)] (4b) was deposited as brown precipitate,
which was filtered off and dried under vacuum (0.053 g, 45% yield).
1H NMR (CDCl3): d 5.31 (d, J = 7.6 Hz, 2H, o-H of NPh), 6.63
(t, J = 7.6 Hz, 1H, p-H of NPh), 6.81 (t, J = 7.6 Hz, 2H, m-H
of NPh), 6.3–6.85 (br, 2H, NPh), remaining 3H of NPh group is
2
4
of [W(k -S2CNHTol)(CNTol)(k -P4)]BF4·2Et2O (6·2Et2O), from
which solvating Et2O molecules were removed by drying under
1
vacuum (0.086 g, 85% yield). H NMR (CDCl3): d 2.24, 2.28
1
overlapping with aromatic signals of P4. 31P{ H} NMR (CDCl3):
(s, 3H each, C6H4Me), 5.29, 6.71, 6.85, 7.00 (d, J = 8.0 Hz, 2H
Existence of two species was observed, although their ratio was
difficult to determine due to severely broad signals; d 45 (vbr, outer
P of the minor), 47 (vbr, outer P of the major), 65 (vbr, inner P of
the major and minor). IR (KBr, cm-1): 1518 m (n(C N)), 1807
brs (n(C N)). Anal. calcd for C60H52N2P4S2W: C, 61.44; H, 4.47;
N, 2.39%. Found C, 61.56; H, 4.51, N, 2.03%.
each, NC6H4), 7.77 (br, 1H, NH, overlapping with the signals
of P4, shifted to 7.79 at 40 ◦C and disappeared by addition of
1
D2O). 31P{ H} NMR (CDCl3): d 56.6 (AA¢XX¢ pattern with 183
W
W
satellites, JPW = 167 Hz, outer P), 66.5 (AA¢XX¢ pattern with 183
satellites, JPW = 197 Hz, inner P), JAX + JAX¢ = 22 Hz. IR (KBr, cm-1):
1084 vs (n(B–F)), 1361 s (n(C–N)), 1804 brs, 1887 sh (n(C N)).
Anal. calcd for C62H57BF4N2P4S2W: C, 57.78; H, 4.46; N, 2.17%.
Found C, 57.43; H, 4.28, N, 2.10%.
Similar reaction of 3·0.5toluene (0.096 g, 0.10 mmol) with
PhNCS (0.039 g, 0.29 mmol) under H2 atmosphere gave 4b
(0.070 g, 60% yield).
Reaction of 4a with MeI
Reaction of 3 with p-ClC6H4NCS
Methyl iodide (8.0 mL, 0.13 mmol) was added into a THF solution
(5 mL) of 4a·0.5toluene (0.136 g, 0.109 mmol). After stirring
the solution at room temperature for 18 h, brick red precipitate
was formed. This was filtered off and dissolved in 3 mL of
CH2Cl2 followed by addition of ether (18 mL). Red brown crystals
A toluene solution (5 mL) of 3·0.5toluene (0.106 g, 0.111 mmol)
and p-ClC6H4NCS (0.057 g, 0.34 mmol) was stirred un-
der N2 atmosphere at 50 ◦C for 12 h.
A brown pre-
4
cipitate of [W(S2CNC6H4Cl-p)(CNC6H4Cl-p)(k -P4)]·0.5toluene
(4c·0.5toluene) was filtered off and dried under vacuum (0.046 g,
32% yield). 1H NMR (CDCl3): d 5.19 (br d, J = 8.0 Hz, C6H4Cl),
6.2–6.8 (vbr, 2H, C6H4Cl), 6.72 (d, J = 8.0 Hz, C6H4Cl), 6.93 (br,
2
4
of [W(k -S2CN(Me)Tol)(CNTol)(k -P4)]I·2CH2Cl2 (7·2CH2Cl2)
were formed, which lost CH2Cl2 solvate after drying under vacuum
(0.104 g, 71% yield). NMR measurements showed the existence
◦
2H, C6H4Cl), 2.36 (s, 1.5H, 0.5toluene). 31P{ H} NMR (CDCl3):
of two geometrical isomers in solution (3 : 1 in CDCl3 at 20 C).
1
Existence of two species was observed, although their ratio was
1H NMR (CDCl3): d 2.23 (br s, 3H, C6H4Me, signals of both
11828 | Dalton Trans., 2011, 40, 11822–11830
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Table 3 Crystallographic data for 4a·THF, 6·2Et2O, 7·2CH2Cl2, and 8·CH2Cl2
4a·THF
6·2Et2O
7·2CH2Cl2
8·CH2Cl2
Formula
FW
C66H64N2OP4S2W
1273.11
P21/n (no. 14)
16.299(2)
14.918(2)
23.741(2)
90
98.9410(4)
90
5703(10)
4
C70H77N2O2BF4P4S2W
1437.06
P1 (no. 2)
C65H63Cl4IN2P4S2W
1512.81
P21/c (no. 14)
17.357(3)
11.468(2)
32.634(6)
90
104.0979(7)
90
6300(2)
C70H63Cl3N2OP4S2W
1426.50
P21/c (no. 14)
14.372(2)
25.725(4)
16.962(3)
90
91.4789(9)
90
6263(18)
4
¯
Space group
˚
a/A
11.907(2)
15.051(2)
19.189(3)
9077.147(5)
89.331(5)
76.838(5)
3261.8(9)
2
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
V/A
Z
4
rc/g cm-3
1.483
2.259
1.463
1.993
1.595
2.705
1.511
2.187
m/mm-1
Crystal size/mm
transmn factor
unique reflns (Rint
obsd reflnsa
variables
0.20 ¥ 0.12 ¥ 0.08
0.716–0.835
13 574 (0.0295)
11141
914
0.0295
0.40 ¥ 0.20 ¥ 0.05
0.522–0.905
15 322(0.040)
12775
855
0.0400
0.25 ¥ 0.20 ¥ 0.20
0.328–0.582
14 995 (0.077)
11714
778
0.0556
0.25 ¥ 0.15 ¥ 0.05
0.698–0.896
14 877 (0.047)
11092
811
0.0372
)
b
R1
wR2
c
0.0958
1.013
0.1145
1.029
0.1541
1.009
0.0816
1.013
Gofd
a Fo > 2 s(Fo2). b R1 = RꢀFo| - |Fcꢀ/R|Fo| for Fo > 2s(Fo2). c wR2 = [Rw(Fo - Fc2)2/Rw(Fo2)2]1/2 for all unique data, where w = [s(Fo2) + a Fo
+
2
2
2
2
b]-1. d gof = [Rw(Fo - Fc2)2/{(no. of reflns obsd) – (no. of variables)}]1/2
.
2
isomers are overlapping), 2.27 (s, 3H of the major, C6H4Me), 2.40
(s, 3H of the minor, C6H4Me), 2.89 (s, NMe of the minor), 2.96
(s, NMe of the major), these two signals are overlapping with
the CH2 signals of P4, 5.23, 6.25, 6.69, 6.94 (d, J = 8.4 Hz,
2H of the major, NC6H4), 5.27, 6.58, 6.71 (d, J = 8.4 Hz, 2H
Rigaku Mercury-CCD diffractometer equipped with a graphite-
˚
monochromatized Mo-Ka source (l = 0.71070 A). Data were
processed using the CrystalClear program package35 and corrected
for absorption. Single crystals of 4c·2.25CH2Cl2 were obtained
by recrystallization from CH2Cl2/hexane. This crystal system
contained three independent molecules in the asymmetric unit,
one of which had considerable disorder. Therefore, the results
of this structure determination are provided as supplementary
information, and included in the ESI.† Details for other crystals
are listed in Table 3. Structure solution and refinements were
performed by using the CrystalStructure program package.36
The positions of non-hydrogen atoms were determined by Pat-
terson methods (PATTY37) and subsequent Fourier synthesis
(DIRDIF9938). These were refined with anisotropic thermal
parameters by full-matrix least-squares techniques. The NH
hydrogen in 6·2Et2O and all the H atoms in the complex part
of 3·THF were found in Fourier maps and refined isotropically.
Other hydrogens were placed at the calculated positions and
included at the final stages of the refinements. The hydrogen atoms
of the disordered moieties in 6·2Et2O and 7·2CH2Cl2 were not
located.
1
of the minor, NC6H4). 31P{ H} NMR (CDCl3): d 56.3 (AA¢XX¢
pattern with 183W satellites, JPW = 170 Hz, outer P), 66.1 (AA¢XX¢
pattern with 183W satellites, JPW = 195 Hz, inner P), JAX + JAX¢
=
21 Hz, for the major isomer; 55.9 (AA¢XX¢ pattern, outer P), 66.4
(AA¢XX¢ pattern, inner P), JAX + JAX¢ = 21 Hz, for the minor
isomer. 183W satellites were not resolved due to low concentration
and signal overlapping. IR (KBr, cm-1): 1374 s (n(C–N)), 1887 brvs
(n(C N)). Anal. calcd for C63H59IN2P4S2W: C, 56.35; H, 4.43; N,
2.09%. Found C, 56.43; H, 4.32, N, 2.08%.
Reaction of 4a with PhCOCl
PhCOCl (12 mL, 0.103 mmol) was added to a THF solution
(5 mL) of 4a·0.5toluene (0.102 g, 0.0819 mmol), and the mix-
ture was stirred at room temperature for 12 h. The deposited
purple solid was filtered off and recrystallized from CH2Cl2
2
(3 mL)/hexane (15 mL) to give purple crystals of [W{k -
4
S2CN(COPh)Tol}(CNTol)(k -P4)]Cl·CH2Cl2 (8·CH2Cl2: 0.099 g,
85% yield). 1H NMR (CDCl3): d 2.23, 2.27 (s, 3H each, C6H4Me),
5.27, 6.27, 6.71, 6.91 (d, J = 8.4 Hz, 2H each, NC6H4), 5.30 (s,
Acknowledgements
1
2H, CH2Cl2). 31P{ H} NMR (CDCl3): d 60.0 (AA¢XX¢ pattern
We thank Ms. Yukiko Tanzawa for experimental assistance. This
work was supported by Grant-in-Aid for Scientific Research on
Priority Areas (No. 18065005, “Chemistry of Concerto Catalysis”
to Y.M.) and Grant-in-Aid for Scientific Research (B) (No.
21350033 to H.S.) from the Ministry of Education, Culture, Sports,
Science and Technology, Japan. H.S. gratefully acknowledges the
special fund of Institute of Industrial Science, The University
of Tokyo. Q.X.D. is grateful to the grant from the GCOE
program (Chemistry Innovation through Cooperation of Science
and Engineering).
with 183W satellites, JPW = 170 Hz, outer P), 64.2 (AA¢XX¢ pattern
with 183W satellites, JPW = 194 Hz, inner P), JAX + JAX¢ = 17 Hz.
IR (KBr, cm-1): 1199 s, 1257 s (n(C–N)), 1682 s (n(C O)), 1930
brvs (n(C N)). Anal. calcd for C70H63Cl3N2OP4S2W: C, 58.94; H,
4.45; N, 1.96%. Found C, 58.60; H, 4.42; N, 1.98%
X-Ray crystallography
Single crystals were mounted on cryoloops with oil and
cooled to 113 K. All diffraction studies were performed on a
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Dalton Trans., 2011, 40, 11822–11830 | 11829
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369; (d) R. S. Amim, M. R. L. Oliveira, G. J. Perpe´tuo, J. Janczak, L.
D. L. Miranda and M. M. M. Rubinger, Polyhedron, 2008, 27, 1891;
(e) B. Singh, M. G. B. Drew, G. Kociok-Kohn, K. C. Molloy and N.
Singh, Dalton Trans., 2011, 40, 623.
Notes and references
1 (a) W. Hewertson and H. R. Watson, J. Chem. Soc., 1962, 1490; (b) J.
Ellermann and K. Dorn, Chem. Ber., 1966, 99, 653; (c) R. B. King and
P. N. Kapoor, J. Am. Chem. Soc., 1969, 91, 5191.
16 Reference 12 and those therein.
2 Reviews: (a) F. A. Cotton and B. Hong, Prog. Inorg. Chem., 1992, 40,
179; (b) H. A. Mayer and W. C. Kaska, Chem. Rev., 1994, 94, 1239;
(c) J.-C. Hierso, R. Amardeil, E. Bentabet, R. Broussier, B. Gautheron,
P. Meunier and P. Kalck, Coord. Chem. Rev., 2003, 236, 143.
3 R. B. King, Acc. Chem. Res., 1972, 5, 177.
4 (a) D. L. DuBois, W. H. Myers and D. W. Meek, J. Chem. Soc., Dalton
Trans., 1975, 1011; (b) R. Ro¨mer, C. Gradert, A. Bannwarth, G. Peters,
C. Na¨ther and F. Tuczek, Dalton Trans., 2011, 40, 3229.
5 (a) S. A. Laneman, F. R. Fronczek and G. G. Stanley, J. Am. Chem.
Soc., 1988, 110, 5585; (b) M. E. Broussard, B. Juma, S. G. Train, W.-J.
Peng, S. A. Laneman and G. G. Stanley, Science, 1993, 260, 1784.
6 (a) C. Arita, H. Seino, Y. Mizobe and M. Hidai, Chem. Lett., 1999, 28,
611; (b) C. Arita, H. Seino, Y. Mizobe and M. Hidai, Bull. Chem. Soc.
Jpn., 2001, 74, 561.
7 (a) H. Seino, D. Watanabe, T. Ohnishi, C. Arita and Y. Mizobe, Inorg.
Chem., 2007, 46, 4784; (b) D. Watanabe, S. Gondo, H. Seino and Y.
Mizobe, Organometallics, 2007, 26, 4909; (c) F. Niikura, H. Seino and
Y. Mizobe, Organometallics, 2009, 28, 1112.
17 (a) N. L. Wagner, F. E. Laib and D. W. Bennett, J. Am. Chem. Soc.,
2000, 122, 10856; (b) S. P. Semproni, W. S. McNeil, R. A. Baillie, B.
O. Patrick, C. F. Campana and P. Legzdins, Organometallics, 2010, 29,
867.
18 H. Kessler and D. Leibfritz, Tetrahedron, 1970, 26, 1805.
19 R. O. Harris, J. Powell, A. Walker and P. V. Yaneff, J. Organomet.
Chem., 1977, 141, 217.
20 (a) D. H. M. W. Thewissen and H. L. M. Van Gaal, J. Organomet.
Chem., 1979, 172, 69; (b) D. H. M. W Thewissen, J. Organomet. Chem.,
1980, 192, 115.
21 F. L. Bowden, R. Giles and R. N. Haszeldine, J. Chem. Soc., Chem.
Commun., 1974, 578.
22 W. Bertleff and H. Werner, Chem. Ber., 1982, 115, 1012.
23 (a) S. R. Finnimore, R. Goddard, S. D. Killops, S. A. R. Knox and P.
Woodward, J. Chem. Soc., Dalton Trans., 1978, 1247; (b) H. Brunner,
H. Buchner and J. Wachter, J. Organomet. Chem., 1983, 244, 247.
24 J. C. Bryan, S. J. Geib, A. L. Rheingold and J. M. Mayer, J. Am. Chem.
Soc., 1987, 109, 2826.
25 T. A. Manuel, Inorg. Chem., 1964, 3, 1703.
26 E. Carmona, A. Galindo, A. Monge, M. A. Munoz, M. L. Poveda and
C. Ruiz, Inorg. Chem., 1990, 29, 5074.
8 Q. X. Dai, H. Seino and Y. Mizobe, Eur. J. Inorg. Chem., 2011, 141.
9 H. Seino, C. Arita, M. Hidai and Y. Mizobe, J. Organomet. Chem.,
2002, 658, 106.
10 (a) G. G. Hlatky and R. H. Crabtree, Coord. Chem. Rev., 1985, 65, 1;
(b) Recent Advances in Hydride Chemistry, ed. M. Peruzzini and R.
Poli, Elsevier, Amsterdam, 2001.
27 M. Cowie and J. A. Ibers, Inorg. Chem., 1976, 15, 552.
28 H. Werner, S. Lotz and B. Heiser, J. Organomet. Chem., 1981, 209, 197.
29 Reaction of trans-[Mo(N2)2(dppe)2] with PhNCS has been reported
to give an S-containing Mo complex and free PhNC: F. Minzoni, C.
Pelizzi and G. Prater, J. Organomet. Chem., 1982, 231, C6.
30 H. Werner and B. Juthani, J. Organomet. Chem., 1981, 209, 211.
31 (a) D. J. Miller and M. R. DuBois, J. Am. Chem. Soc., 1980, 102, 4925;
(b) C. C. Hadjikostasa, G. A. Katsoulosa and S. K. Shakhatreha, Inorg.
Chim. Acta, 1987, 133, 129; (c) J. Li, D. Miguel, D. Morales, V. Riera,
A. Aguirre-Pe´rez and S. Garcia-Granda, Dalton Trans., 2003, 3264.
32 (a) A. Mayr and C. M. Bastos, Prog. Inorg. Chem., 1992, 40, 1; (b) A. C.
Filippou, in Organic Synthesis via Organometallics, ed. G. Helmchen,
J. Dibo, D. Flubacher and B. Wiese, F. Vieweg & Sohn, Braunschweg,
1997, p. 97; (c) A. J. L. Pombeiro, M. F. C. Guedes da Silva and R. A.
Michelin, Coord. Chem. Rev., 2001, 218, 43.
33 (a) J. L. Templeton and B. C. Ward, Inorg. Chem., 1980, 19, 1753; (b) J.
L. Templeton and B. C. Ward, J. Am. Chem. Soc., 1981, 103, 3743; (c) E.
Carmona, L. Contreras, M. L. Poveda, L. J. Sanchez, J. L. Atwood and
R. D. Rogers, Organometallics, 1991, 10, 61; (d) C. G. Young, M. A.
Bruck, P. A. Wexler, M. D. Carducci and J. H. Enemark, Inorg. Chem.,
1992, 31, 587; (e) P. J. Lim, D. A. Slizys, E. R. T. Tiekink and C. G.
Young, Inorg. Chem., 2005, 44, 114.
34 R. D. Adams and M. Huang, Polyhedron, 1998, 17, 2759.
35 CrystalClear 1.3.6, Rigaku/MSC, The Woodlands, TX, USA, 2006.
36 CrystalStructure 3.8.2, Rigaku/MSC, The Woodlands, TX, USA,
2007.
37 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman, S. Garcia-
Granda, R. O. Gould, J. M. M. Smits and C. Smykall, PATTY:
The DIRDIF program system, Technical report of the crystallography
laboratory, University of Nijmegen, Nijmegen, The Netherlands, 1992.
38 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman,
R. de Gelder, R. Israel and J. M. M. Smits, DIRDIF99: The
DIRDIF-99 program system, Technical report of the crystallography
laboratory, University of Nijmegen, Nijmegen, The Netherlands,
1999.
11 Reviews: (a) H. Werner, Coord. Chem. Rev., 1982, 43, 165; (b) J. Louie,
Curr. Org. Chem., 2005, 9, 605.
12 T. Ohnishi, H. Seino, M. Hidai and Y. Mizobe, J. Organomet. Chem.,
2005, 690, 1140.
13 (a) S. D. Robinson and A. Sahajpal, J. Organomet. Chem., 1976, 111,
C26; (b) S. D. Robinson and A. Sahajpal, Inorg. Chem., 1977, 16,
2722; (c) J. F. Leboeuf, J. C. Leblance and C. Moise, J. Organomet.
Chem., 1987, 335, 331; (d) M. Wang, S. Lu, M. Bei, H. Guo and Z.
Jin, J. Organomet. Chem., 1993, 447, 227; (e) A. Antinolo, F. Carrillo-
Hermosilla, S. Garcia-Yuste, M. Freitas, A. Otero, S. Prashar, E.
Villasenor and M. Fajardo, Inorg. Chim. Acta, 1997, 259, 101; (f) L. D.
Field, W. J. Shaw and P. Turner, Organometallics, 2001, 20, 3491; (g) L.
D. Field, W. J. Shaw and P. Turner, Chem. Commun., 2002, 46; (h) G
Albertin, S. Antoniutti and G. Roveda, Inorg. Chim. Acta, 2005, 358,
3093.
14 (a) R. Schierl, U. Nagel and W. Beck, Z. Naturforsch., 1984, 39b, 649;
(b) Y.-P. Tian, C.-Y. Duan, Z.-L. Lu, X.-Z. You, H.-K. Fun and B.-C.
Yip, Polyhedron, 1996, 15, 1495; (c) S. B. Schougaard, K. F. Thomas,
S. Larsen, H. O. Sorensen, D. R. Greve and T. Bjornholm, Acta
Crystallogr., Sect. C: Cryst. Struct. Commun., 1998, 54, 470; (d) M.
B. Dinger and W. Henderson, J. Chem. Soc., Dalton Trans., 1998, 1763;
(e) D. E. Schwarz and T. B. Rauchfuss, Chem. Commun., 2000, 1123;
(f) A. Mallard, J. Marrot, C. Simonnet-Jegat and F. Secheresse, Inorg.
Chim. Acta, 2007, 360, 3436; (g) K.-E. Lee, X. Chang, Y.-J. Kim, H.
S. Huh and S. W. Lee, Organometallics, 2008, 27, 5566; (h) Y. Kim, H.
Jeon, K. Lee and S. W. Lee, J. Organomet. Chem., 2010, 695, 2258.
15 Dithiocarbonimidate ligands having an electron-withdrawing N-
substituents (CN, COOEt, SO2R) show relatively short C–S and long
C–N distances: (a) F. A. Cotton and C. B. Harris, Inorg. Chem., 1968,
7, 2140; (b) J. Ahmed, K. Itoh, I. Matsuda, F. Ueda, Y. Ishii and J. A.
Ibers, Inorg. Chem., 1977, 16, 620; (c) C. J. Burchell, S. M. Aucott, H.
L. Milton, A. M. Z. Slawin and J. D. Woollins, Dalton Trans., 2004,
11830 | Dalton Trans., 2011, 40, 11822–11830
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