Synthesis and characterization of iron(II) and ruthenium(II) hydrido hydrazine complexes

Article abstract of DOI:10.1021/ic102519f

Treatment of trans-[MHCl(dmpe)₂] (M = Fe, Ru) with hydrazine afforded the hydrido hydrazine complexes cis- and trans-[MH(N₂H ₄)(dmpe)₂]⁺ which have been characterized by NMR spectroscopy (¹

Full text of DOI:10.1021/ic102519f

ARTICLE
pubs.acs.org/IC
Synthesis and Characterization of Iron(II) and Ruthenium(II) Hydrido
Hydrazine Complexes
Leslie D. Field,*,† Hsiu L. Li,†,‡ Scott J. Dalgarno,§,^ Paul Jensen,‡ and Ruaraidh D. McIntosh^
†School of Chemistry, University of New South Wales, New South Wales 2052, Australia
‡School of Chemistry, University of Sydney, New South Wales 2006, Australia
§Department of Chemistry, University of Missouri—Columbia, Columbia, Missouri 65211, United States
^School of Engineering and Physical Sciences-Chemistry, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, U.K.
S Supporting Information
b
ABSTRACT: Treatment of trans-[MHCl(dmpe)2] (M = Fe,
Ru) with hydrazine afforded the hydrido hydrazine complexes
cis- and trans-[MH(N2H4)(dmpe)2]þ which have been char-
acterized by NMR spectroscopy (1H, 31P, and 15N). Both cis and
trans isomers of the Fe complex and the trans isomer of the Ru
complex were characterized by X-ray crystallography. Reactions
with acid and base afforded a range of N2Hx complexes, including several unstable hydrido hydrazido complexes.
’ INTRODUCTION
Scheme 1
The conversion of dinitrogen to ammonia can be achieved
biologically by the nitrogenase metalloenzymes or industrially by
the HaberꢀBosch process. One feature common to both of these
processes is that iron is the key metal in the active catalyst.1
Ruthenium compounds are also used as industrial catalysts for
ammonia synthesis,2 and ruthenium complexes are of interest as
they frequently stabilize reactive intermediates that are too unstable
to be isolated or characterized on the analogous iron complexes.3
Research into the mechanism of nitrogenase action has highlighted
that metal-bound hydrides4 and hydrazines5 are important potential
reaction intermediates in dinitrogen reduction. Metal complexes
containing both hydride and hydrazine ligands are known for Ru,
Ir, Os, and Re6 although only one example on Fe is known
[FeH(N2H4){P(OEt)3}]þ where the hydride and hydrazine ligands
were shown to be in mutually cis coordination sites.7 None of these
hydrido hydrazine complexes have been structurally characterized.
In this paper we report the synthesis and characterization of
iron and ruthenium phosphine complexes containing both
hydride and hydrazine ligands. This type of metal complex
may play an important role as an intermediate in the Leigh8 or
Tyler9 systems for dinitrogen conversion to ammonia. While
several mechanistic pathways have been proposed for dinitrogen
reduction in iron phosphines and some have been investigated
computationally,10 none of the postulated intermediate struc-
tures have so far contained both hydride and hydrazine ligands.
complex trans-[FeH(N2H4)(dmpe)2]þ (2t) (Scheme 1) in an
approximate ratio of 1.3:1 (by 31P{1H} NMR spectroscopy). This
is probably an equilibrium mixture with competition between
chloride and hydrazine for the metal coordination site. On stand-
ing, yellow needles of the chloride salt of the hydrido hydrazine
complex trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl) formed, and
these were characterized by X-ray crystallography. An ORTEP
depiction of 2t-Cl is shown in Figure 1. The geometry about iron is
that of a slightly distorted octahedron with the hydride and
hydrazine ligands in mutually trans positions. The hydrazine is
bound end-on, and the FeꢀN distance of 2.0927(11) Å is within
the range of those reported for other iron complexes containing
end-on bound hydrazine ligands (2.042(3)ꢀ2.224(5) Å).11,12 The
NꢀN bond length of 1.4635(17) Å is slightly longer than those
reported for other ironꢀhydrazine complexes (1.432(10)ꢀ1.460
Å), including those with side-on or bridging hydrazines,11ꢀ14
although shorter than the bridging hydrazine ligand in
{[PhBPPh3]Fe}2(μꢀη1:η1-N2H4)(μꢀη2:η2-N2H2) (PhBPPh
=
3
PhB(CH2PPh2)3ꢀ) (1.465(3) Å).15 One proton on the terminal
nitrogen is disordered over two positions at 50% occupancy each.
’ RESULTS AND DISCUSSION
Iron Hydrido Hydrazine Complexes. Treatment of trans-
[FeHCl(dmpe)2] (dmpe =1,2-bis(dimethylphosphino)ethane)
(1t) with approximately 6 equiv of hydrazine in tetrahydrofuran
afforded a mixture of the starting material 1t and the hydrazine
Received: December 16, 2010
Published: May 27, 2011
r
2011 American Chemical Society
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ARTICLE
Figure 2. 1Hꢀ N HSQC spectrum of trans-[FeH(N2H4)(dmpe)2]þ-
15
[BPh4]ꢀ (2t-BPh4) (300 K, thf-d8).
Figure 1. ORTEP depiction of trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-
Cl) (50% displacement ellipsoids, chloride counterion, hydrazine sol-
vate, hydrogen atoms on the phosphine ligands, and one of the two
disordered hydrogen atoms on the terminal nitrogen with 50% occu-
pancy have been excluded for clarity). Selected bond lengths (Å) and
angles (deg): Fe1ꢀN1, 2.0927(11); Fe1ꢀP3, 2.1867(4); Fe1ꢀP4,
2.1961(4); Fe1ꢀP2, 2.2050(4); Fe1ꢀP1, 2.2149(4); Fe1ꢀH1,
1.49(2); N1ꢀN2, 1.4635(17); N1ꢀFe1ꢀP3, 95.50(4); N1ꢀFe1ꢀP4,
91.54(3); P3ꢀFe1ꢀP4, 85.914(16); N1ꢀFe1ꢀP2, 92.28(4);
P3ꢀFe1ꢀP2, 171.959(17); P4ꢀFe1ꢀP2, 95.931(17); N1ꢀFe1ꢀP1,
99.37(3); P3ꢀFe1ꢀP1, 91.975(16); P4ꢀFe1ꢀP1, 169.039(16);
P2ꢀFe1ꢀP1, 84.734(17); N1ꢀFe1ꢀH1, 175.9(8); P3ꢀFe1ꢀH1,
85.0(8); P4ꢀFe1ꢀH1, 84.4(8); P2ꢀFe1ꢀH1, 87.4(8); P1ꢀFe1ꢀH1,
84.7(8); N2ꢀN1ꢀFe1, 119.28(8).
The hydrazine complex 2t-Cl is unstable in solution and, in the
absence of excess hydrazine, loses hydrazine and reverts to the
starting material 1t within a matter of hours. NMR data were
acquired as quickly as possible after dissolution of the sample or
in the presence of excess 15N2-hydrazine for the collection of
15N NMR spectra. The pentet at ꢀ28.9 ppm (2JHP = 49 Hz) for
at 68.9 ppm in the 31P{1H} NMR spectrum (broad doublet,
2JHP = 49 Hz, without 1H decoupling) confirm the trans confi-
guration of the complex. The two 15N signals at ꢀ311.1 and
ꢀ371.3 ppm confirm the end-on binding of the hydrazine ligand.
The hydrido hydrazine complex was isolated as ꢀthe tetraphe-
nylborate salt trans-[FeH(N2H4)(dmpe)2]þBPh4 (2t-BPh4)
in moderate yield on addition of NaBPh4 to a solution of 2t-Cl in
methanol under an argon atmosphere. If the anion exchange
reaction was carried out under nitrogen, an appreciable quantitꢀy
of the dinitrogen complex16 trans-[FeH(N2)(dmpe)2]þBPh4
was also formed, underlining the inherent lability of the hydra-
zine ligand. The hydride and phosphine chemical shifts are
similar to those for the Cl salt 2t-Cl.
Figure 3. 15N{1H} spectrum of trans-[FeH(15N2H4)(dmpe)2]þ-
[BPh4]ꢀ (2t-BPh4) (300 K, thf-d8).
1
the hydride ligand in the H NMR spectrum and the singlet
The 15N2 analogue of hydrazine complex 2t-BPh4 was prepared
in an analogous fashion to that used to synthesize unlabeled
2t-BPh4 using 15N2-hydrazine. In the 1H NMR spectrum, both
signals for the nitrogen-bound protons of the coordinated
hydrazine ligand exhibit additional coupling to 15N (1JHN
=
69.4 Hz, 1JHN = 63.9 Hz). In the 15N{1H} spectrum (FigureR3),
the downfieldβsignal (assigned to Nβ) is a doublet of pentets due
to coupling to the other N atom (1JNN = 6.6 Hz) and coupling to
four equivalent P atoms (JNP = 1.9 Hz). The upfield signal (NR)
does not exhibit any discernible coupling to phosphorus,
and this is unusual as in this case, |3JNP| > |2JNP|, unlike the case
for dinitrogen complexes [FeH(N2)(PP)2]þ where typically
|2JNP| > |3JNP|.19 In the 15N spectrum with decoupling of the
low-field proton region, the signal for NR shows an additional
splitting due to the metal-bound hydride ligand which is again
consistent with the nitrogen assignments.
The nitrogen-bound protons of the coordinated hydrazine ligand
of 2t-BPh4 appear at 2.78 and 2.34 ppm in the 1H NMR spectrum.
Only the downfield resonance exhibits weak coupling to 31P, and,
on this basis, we assign this to the protons on the nitrogen bound to
iron (NRH). The 15N chemical shifts of the hydrazine ligand were
The hydrido hydrazine complex 2t-BPh4 is unstable in solu-
tion; however, unlike the chloride salt 2t-Cl which readily loses
hydrazine to regenerate 1t, 2t-BPh4 reacts over time with NꢀN
bond cleavage to form the hydrido ammine complex trans-[FeH-
(NH3)(dmpe)2]þ (3) on standing as observed by 1H, 31P, and
15N NMR spectroscopies. In the several hours required to
acquire the 15N data for 2t-BPh4, the signal for 3 at ꢀ433.7
ppm can already be observed, and small amounts of free 15N2
(ꢀ72.3 ppm) and trans-[FeH(15N2)(dmpe)2]þ (ꢀ48.2 and
ꢀ63.2 ppm)19 are also observable in the 15N NMR spectrum.
1
15
obtained from a 2D Hꢀ N correlation experiment (at natural
abundance) where the 1H resonance at 2.78 ppm correlates to the
1
15N signal at ꢀ373.2 ppm, while the H resonance at 2.34
ppm correlates to the 15N signal at ꢀ311.0 ppm (Figure 2). In
this way the 15N signals at ꢀ373.2 and ꢀ311.0 ppm were assigned
to NR and Nβ, respectively. These shifts are comparable to those
reported for Rh and Ru complexes with end-on bound hydrazine
ligands where δ(NR) appears to high field of δ(Nβ).17,18
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The decomposition reaction proceeds at a relatively slow rate
and is most likely the result of disproportionation. Hydrazine is
known to disproportionate to ammonia and dinitrogen or
diazene especially in the presence of metal complexes.20 Cross-
land and Tyler have reported a similar decomposition of
coordinated hydrazine in trans-[FeH(N2H4)(DMeOPrPE)2]þ
(DMeOPrPE = 1,2-bis(dimethoxypropylphosphino)ethane).1
An authentic sample of the hydrido ammine complex
trans-[FeH(NH3)(dmpe)2]þ[BPh4]ꢀ (3-BPh4) was prepared
independently, in good yield, by reaction of 1t with ammonia in
the presence of sodium tetraphenylborate in ethanol (Scheme 1).
Care had to be taken to maintain an atmosphere of ammonia
when the complex was in solution because there was relatively
facile substitution of ammonia by dinitrogen. The pentet at
1
ꢀ30.1 ppm in the H NMR spectrum and the singlet at 69.0
ppm in the 31P NMR spectrum confirm that the complex has a
1
15
Figure 4. ORTEP depiction of cis-[FeH(N2H4)(dmpe)2]þClꢀ (2c-
Cl) (50% displacement ellipsoids, chloride counterion, hydrazine sol-
vate, hydrogen atoms on the phosphine ligands, and atoms with 20%
occupancy have been excluded for clarity). Selected bond lengths (Å)
and angles (deg): Fe1ꢀN1, 2.095(3); Fe1ꢀP2, 2.172(3); Fe1ꢀP1,
2.2091(11); Fe1ꢀP4, 2.2105(11); Fe1ꢀP5, 2.247(2); Fe1ꢀH1,
1.60(4); N1ꢀN2, 1.462(5); N1ꢀFe1ꢀP2, 170.24(12); N1ꢀFe1ꢀP1,
89.19(10); P2ꢀFe1ꢀP1, 84.40(7); N1ꢀFe1ꢀP4, 88.41(10);
P2ꢀFe1ꢀP4, 96.91(7); P1ꢀFe1ꢀP4, 171.71(5); N1ꢀFe1ꢀP5,
91.00(11); P2ꢀFe1ꢀP5, 97.54(9); P1ꢀFe1ꢀP5, 102.27(5);
P4ꢀFe1ꢀP5, 85.70(5); N1ꢀFe1ꢀH1, 86.9(14); P2ꢀFe1ꢀH1,
85.3(14); P1ꢀFe1ꢀH1, 85.7(14); P4ꢀFe1ꢀH1, 86.2(14);
P5ꢀFe1ꢀH1, 171.7(14); N2ꢀN1ꢀFe1, 117.4(2).
trans geometry in solution. A 2D Hꢀ N correlation experi-
ment shows the 1H NH3 resonance at ꢀ0.09 ppm correlates to a
15N signal at ꢀ433.1 ppm. The 15N labeled analogue of 3 was
prepared by allowing a solution of 15N-labeled hydrazine com-
plex 2t-BPh4 to stand for several days. The nitrogen-bound
1
protons of the coordinated ammonia ligand in the H NMR
spectrum show coupling to 15N (1JHN = 65.5 Hz) as well as to 31
P
(3JHP = 2.9 Hz). Bergman et al. have synthesized this hydrido
ammine complex, albeit with different counterions, via proton-
ation of the amido group in [FeH(NH2)(dmpe)2] with fluorene
or water.21
Crystals of cis-[FeH(N2H4)(dmpe)2]þClꢀ (2c-Cl, Scheme 1)
were obtained from a tetrahydrofuran (THF) solution of a
mixture of 1t, hydrazine, and the hydrazine complex 2t-Cl when
it was left to stand over an extended period (months). Presum-
ably there is an equilibrium between the cis and trans isomers,
and while the equilibrium favors the trans isomer, the cis isomer
forms a stable crystalline solid which precipitates from solution
over time. An ORTEP diagram of 2c-Cl is shown in Figure 4. The
geometry about iron is that of a slightly distorted octahedron
with the hydride and hydrazine ligands occupying mutually cis
coordination sites. The hydrazine ligand is bound end-on, and
the FeꢀN and NꢀN bond distances of 2.095(3) and 1.462(5) Å
are similar to those observed for the trans isomer 2t-Cl.
The multiplet at ꢀ11.2 ppm for the hydride ligand in the 1H
NMR spectrum and the four ddd signals in the 31P NMR
spectrum confirm the presence of two different ligands in
mutually cis coordination sites. 15N NMR signals at ꢀ298.0
and ꢀ377.6 ppm are similar to those for 2t-Cl and confirm the
presence of an end-on bound hydrazine ligand.
by 15N NMR spectroscopy (Scheme 2). In this reaction, the hydride
ligand is presumably protonated and lost as H2 by reaction with acid
and the pendant NH2 of the hydrazine ligand fills the vacant
coordination site resulting in a side-on bound hydrazine. Subsequent
reaction of [Fe(η2-N2H4)(dmpe)2]2þ with acid affords ammonium
as previously described.22
Treatment of 15N-labeled 2t-BPh4 with excess KOtBu in
tetrahydrofuran afforded a complex mixture of reaction products
including the iron diazene complex [Fe(η2-N2H2)(dmpe)2]
(δ(15N) = ꢀ312.8 ppm), the iron(0) dinitrogen complex
[Fe(N2)(dmpe)2] (δ(15N) = ꢀ44.9, ꢀ49.0 ppm), and the
iron(II) dihydride complex [FeH2(dmpe)2] as the major identi-
fiable products (Scheme 3). Both H2 and N2 are products of the
disproportionation of diazene, so the formation of [Fe(N2)-
(dmpe)2] and [FeH2(dmpe)2] in the reaction mixture is not
unreasonable. During the early stages of the reaction, the side-on
bound hydrazine complex [Fe(η2-N2H4)(dmpe)2]2þ (δ(15N) =
ꢀ388.0 ppm) is also observed as a minor product. This is
presumably formed by deprotonation of the metal hydride 2t-
BPh4 and oxidation under the reaction conditions. [Fe(η2-
N2H4)(dmpe)2]2þ is known to form the diazene complex
[Fe(η2-N2H2)(dmpe)2] under basic conditions22 and disap-
pears as the reaction progresses.
The cis isomer 2c-Cl was also obtained by irradiation of a
solution of 1t and hydrazine in tetrahydrofuran (Scheme 1).
Apart from slow crystallization, complex 2c-Cl could not be
isolated isomerically pure in a bulk reaction and the product
typically contained variable amounts of trans isomer 2t-Cl.
Irradiation of 1t in the absence of hydrazine afforded a mixture
of 1t and the cis isomer 1c in an approximate ratio of 7.5:1. The
cis isomer 1c has a hydride resonance at ꢀ10.96 ppm and four
31P resonances at 80.5, 73.6, 67.4, and 53.2 ppm. However, on
standing overnight, 1c reverts back to 1t.
Reactions of Iron Hydrido Hydrazine Complexes. Treat-
ment of 15N-labeled hydrido hydrazine complex 2t-BPh4 with an
excess of a weak acid (2,6-lutidinium triflate) in tetrahydrofuran,
afforded a mixture of reaction products of which the known side-on
bound hydrazine complex [Fe(η2ꢀN2H4)(dmpe)2]2þ (δ(15N) =
ꢀ389.0 ppm)13 and NH4þ (δ(15N) = ꢀ365.4 ppm) were detected
Interestingly, if, instead of the tetraphenylborate salt, the chloride
salt 2t-Cl was treated with KOtBu, the major products appear to
result from single deprotonation of the coordinated hydrazine to
give the hydrido hydrazido complexes [FeH(N2H3)(dmpe)2] as a
mixture of cis (4c) and trans (4t) isomers (Scheme 3). The
products are highly unstable and rapidly decompose to form
[Fe(N2)(dmpe)2], [FeH2(dmpe)2], and a suite of other unidenti-
fied products presumably via the metal diazene complex. Isomers 4c
and 4t have only been characterized as transient species spectro-
scopically, and while the structure of these complexes is speculative
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Scheme 2
Scheme 3
at this stage, the hydride resonances at ꢀ11.27 and ꢀ26.05 ppm for
4c and 4t, respectively, are close to those reported by Bergman for
the analogous hydrido amido complexes cis- and trans-[FeH(NH2)-
(dmpe)2] (ꢀ11.30 and ꢀ25.97 ppm, respectively).23 Four reso-
nances were observed in the 15N NMR spectrum at ꢀ275.9,
ꢀ308.8, ꢀ369.6, and ꢀ378.4 ppm for the two different nitrogen
atoms in the two isomeric complexes. No NH protons were
observed probably due to rapid exchange on the NMR time scale
under the reaction conditions. Only one example of an iron
hydrazido(1ꢀ) complex has been reported so far, cis-[Fe-
(DMeOPrPE)2(N2H3)]þ, where the hydrazido ligand is bound
side-on (δ(15N) = ꢀ375 ppm at room temperature, ꢀ367.6,
ꢀ369.9 ppm at 193 K).24 No iron hydrazido(1ꢀ) complexes have
been reported with a hydride coligand. Hydrazido(1ꢀ) complexes
are considered rare and also known to be unstable.25
Scheme 4
The difference in reactivity between 2t-Cl and 2t-BPh4 is
surprising but could be attributed to their different stabilities,
solubilities, and ease of deprotonation. Complex 2t-BPh4 is more
soluble in the reaction mixture and probably reacts more rapidly
with the tert-butoxide base.
Ruthenium Hydrido Hydrazine Complexes. Treatment of
trans-[RuHCl(dmpe)2] (5t) with hydrazine afforded trans-[RuH-
(N2H4)(dmpe)2]þClꢀ (6t-Cl) as a white solid (Scheme 4).
Although 6t-Cl loses hydrazine in solution to reform 5t such as
its iron analogue, it does not readily coordinate nitrogen while
dissolved in methanol or ethanol. Thus, the anion exchange with
NaBPh4 in methanol could be carried out under nitrogen and
afforded the complex as the tetraphenylborate salt trans-[RuH-
(N2H4)(dmpe)2]þBPh4ꢀ (6t-BPh4). Crystals of 6t-BPh4 suita-
ble for X-ray crystallography were obtained from a solution of
6t-Cl and NaBPh4 in methanol, and an ORTEP depiction is
shown in Figure 5. There is a slightly distorted octahedral
arrangement of donors about ruthenium with the hydride and
hydrazine (bound end-on) ligands in mutually trans positions.
The RuꢀN distance of 2.2728(13) Å is longer than those
previously reported for ruthenium hydrazine complexes
(2.162(2)ꢀ2.225(3) Å),3,12,18,26 perhaps reflecting the large trans
influence of the hydride ligand. The NꢀN distance of 1.4632(18)
Å is within the range reported for other ruthenium hydrazine
complexes (1.378(10)ꢀ1.479(5) Å).
As for the analogous Fe complex, the pentet at ꢀ20.56 ppm in
1
the H NMR spectrum and the singlet at 41.1 ppm in the
31P{1H} NMR spectrum confirm the trans geometry of
6t-BPh4. The broad resonances at 3.42 and 2.64 ppm correlate
to 15N signals at ꢀ372.9 and ꢀ310.1 ppm for NR and Nβ,
respectively.
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Scheme 5
bridging hydrazido(1ꢀ) ligands, and two examples have been
described with bridging hydride coligands.28
’ CONCLUSIONS
In this paper we have reported the synthesis and characteriza-
tion of a series of iron and ruthenium complexes containing both
hydride and hydrazine ligands. In particular, both cis and trans
isomers of iron and ruthenium were characterized by NMR
spectroscopy (1H, 31P, and 15N) and X-ray crystallography. To
the best of our knowledge, these are the first complexes contain-
ing both hydride and hydrazine ligands to be structurally char-
acterized. The iron hydrido hydrazine complexes are unstable in
solution, and the hydrazine ligand is labileand readily displaced by
chloride or dinitrogen. Tꢀhe coordinated hydrazine in trans-[FeH-
(N2H4)(dmpe)2]þBPh4 (2t-BPh4) breaks down with NꢀN
bond cleavage to give the hydrido ammine complex trans-[FeH-
(NH3)(dmpe)2]þ (3-BPh4). Treatment of 2t-BPh4 with a weak
acid produces [Fe(η2-N2H4)(dmpe)2]2þ with a side-on bound
hydrazine ligand. Treatment with base produces the known iron
diazene complex [Fe(η2-N2H2)(dmpe)2]. Treatment of the
chloride salts of either trans-[FeH(N2H4)(dmpe)2]þ (2t-Cl) or
trans-[RuH(N2H4)(dmpe)2]þ (6t-Cl) with base produces the
hydrazido hydride complexes [MH(N2H3)(dmpe)2] (4t, 4c,
and 7t).
ꢀ
Figure 5. ORTEP depiction of trans-[RuH(N2H4)(dmpe)2]þBPh4
(6t-BPh4) (50% displacement ellipsoids, tetraphenylborate counterion,
and hydrogen atoms on the phosphine ligands have been excluded for
clarity). Selected bond lengths (Å) and angles (deg): Ru1ꢀN1,
2.2728(13); Ru1ꢀP3, 2.3135(5); Ru1ꢀP4, 2.3203(5); Ru1ꢀP1,
2.3263(5); Ru1ꢀP2, 2.3291(6); Ru1ꢀH1, 1.603(13); N1ꢀN2,
1.4632(18); N1ꢀRu1ꢀP3, 95.91(4); N1ꢀRu1ꢀP4, 92.32(4);
P3ꢀRu1ꢀP4, 83.97(2); N1ꢀRu1ꢀP1, 91.52(4); P3ꢀRu1ꢀP1.
172.540(15); P4ꢀRu1ꢀP1, 96.36(2); N1ꢀRu1ꢀP2, 98.32(4);
P3ꢀRu1ꢀP2, 95.39(2); P4ꢀRu1ꢀP2, 169.347(15); P1ꢀRu1ꢀP2,
82.90(2); N1ꢀRu1ꢀH1, 177.5(6); P3ꢀRu1ꢀH1, 85.9(6);
P4ꢀRu1ꢀH1, 86.2(6); P1ꢀRu1ꢀH1, 86.7(6); P2ꢀRu1ꢀH1,
83.2(6); N2ꢀN1ꢀRu1, 117.42(9).
Irradiation of 5t afforded a mixture enriched in the cis isomer
(cis-[RuHCl(dmpe)2], 5c) where the approximate ratio of cis
and trans isomers was 5.7:1, respectively (Scheme 4). Complete
conversion of the trans isomer to the cis isomer was not achieved
despite prolonged irradiation. Unlike the case for iron, where 1c
reverted to the trans isomer 1t on standing overnight, 5c was
stable indefinitely. Addition of hydrazine afforded cis-[RuH-
(N2H4)(dmpe)2]þClꢀ (6c-Cl) (Scheme 4) and variable
amounts of the trans isomer 6t-Cl. The multiplet at ꢀ8.33
’ EXPERIMENTAL SECTION
All manipulations of metal complexes and air-sensitive reagents were
carried out using standard Schlenk techniques or in nitrogen- or argon-
filledgloveboxes. Solvents were dried and distilled undernitrogenor argon
from sodium/benzophenone (tetrahydrofuran, hexane, and diethylether),
calcium hydride (acetonitrile), dimethoxymagnesium (methanol), and
diethoxymagnesium (ethanol). Tetrahydrofuran (inhibitor-free) and pen-
tane were dried and deoxygenated using a Pure Solv 400-4-MD
(Innovative Technology) solvent purification system. Deuterated solvents
were purchased from Aldrich, Merck, or Cambridge Isotope Laboratories.
Tetrahydrofuran-d8, toluene-d8, and benzene-d6 were dried over and
distilled from sodium/benzophenone.
1
ppm in the H NMR spectrum and the four multiplets in the
31P{1H} NMR spectrum at 49.6, 42.3, 39.9, and 31.3
ppm confirm the presence of two different ligands in mutually
cis positions. 15N resonances at ꢀ298.4 and ꢀ374.2 ppm for Nβ
and NR, respectively, were obtained from a 15N2 analogue of 6c-
Cl where couplings to 31P ranging from 2 to 25 Hz were
observed. Crystals of 6c-Cl were examined by X-ray crystal-
lography; although refinement to acceptable publication stan-
dard was not possible, the atom connectivity and stereochemistry
of the complex were clearly demonstrated with the hydrazine and
hydrido ligands in mutually cis positions.
Potassium tert-butoxide was resublimed before use. 2,6-Lutidinium
triflate was prepared by reaction of 2,6-lutidine with an equimolar
amount of triflic acid in toluene. Hydrazine (1 M in tetrahydrofuran)
was purchased from Aldrich and deoxygenated before use. Hydrazi-
Treatment of 6t-Cl with KOtBu afforded the unstable hydrido
hydrazido complex trans-[RuH(N2H3)(dmpe)2] (7t) as well as
[RuH2(dmpe)2] and other unidentified products (Scheme 5).
Only the trans isomer was observed unlike the case for the
analogous iron complexes which were a mixture of cis and trans
isomers (4c/4t). The hydride resonance at ꢀ19.33 ppm is upfield
of the resonance for the hydrido amido complex trans-[RuH-
(NH2)(dmpe)2] (ꢀ16.57 ppm).27 The two resonances in the 15N
spectrum are observed at ꢀ306.8 and ꢀ365.9 ppm and do not
exhibit proton coupling even at 200 K, similar to the analogous
iron hydrido hydrazido complexes 4c/4t. No mononuclear ruthe-
nium hydrazido(1ꢀ) complexes have been reported previously.
Dinuclear and trinuclear ruthenium complexes are known with
ne-15N2 was prepared by Soxhlet extraction of 15N2H4 H2SO4 with
3
liquid ammonia.29 Ammonia saturated ethanol or tetrahydrofuran was
obtained by bubbling anhydrous ammonia gas into the appropriate
solvent for several minutes. The complexes trans-[FeHCl(dmpe)2] (1t)
and trans-[RuHCl(dmpe)2] (5t) were prepared using modifications of
the literature methods.22,30 Irradiation was carried out using a 300 W
high-pressure mercury vapor lamp with the incident beam directed
through a water-filled jacket to filter out infrared radiation.
Air-sensitive NMR samples were prepared in argon- or nitrogen-filled
gloveboxes or on a high-vacuum line by vacuum transfer of solvent into
1
an NMR tube fitted with a concentric Teflon valve. H, 31P, 15N, and
two-dimensional NMR spectra were recorded on a Bruker DMX600,
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Table 1. Crystallographic Data for trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl), cis-[FeH(N2H4)(dmpe)2]þClꢀ (2c-Cl), and
trans-[RuH(N2H4)(dmpe)2]þBPh4ꢀ (6t-BPh4)
2t-Cl
2c-Cl
6t-BPh4
formula
M (g molꢀ1
cryst syst
space group
a (Å)
C12H40ClFeN3.5P4
448.66
C12H41ClFeN4P4
456.67
C36H57BN2P4Ru
753.60
)
monoclinic
P21/n (No. 14)
9.0906(8)
27.982(2)
9.9025(8)
115.2990(10)
2277.3(3)
1.309
monoclinic
P21/c
monoclinic
P21/n (No. 14)
13.252(3)
18.373(4)
15.893(4)
98.759(10)
3824.5(14)
1.309
16.404(3)
9.0876(14)
17.938(2)
121.583(12)
2278.0(6)
1.332
b (Å)
c (Å)
β (deg)
V (Å3)
Dc (g cmꢀ3
)
Z
4
4
4
T (K)
150(2)
173(2)
100(2)
μ(Mo KR) (mmꢀ1
cryst size (mm)
cryst color
)
1.061
1.062
0.604
0.47 ꢁ 0.22 ꢁ 0.10
yellow
0.23 ꢁ 0.14 ꢁ 0.10
colorless
0.20 ꢁ 0.10 ꢁ 0.10
colorless
cryst habit
needle
prism
block
T(Gaussian)min,max
2θmax (deg)
hkl range
0.775, 0.901
56.66
0.7922, 0.9012
54.24
0.8887, 0.9421
73.14
ꢀ11 11, ꢀ36 36, ꢀ13 13
22 420
ꢀ20 21, ꢀ10 11, ꢀ22 17
15 848
ꢀ20 22, ꢀ30 30, ꢀ26 26
70 455
N
Nind
5488 (Rmerge 0.0248)
4882
5009 (Rint = 0.0283)
4344
18153 (Rint = 0.0512)
12547
Nobs (I > 2σ(I))
goodness of fit
R1 (F, I > 2σ(I))
wR2 (F2, all data)
1.085
1.180
1.019
0.0264
0.0557
0.0391
0.0718
0.1295
0.0702
DMX500, DRX400, or DPX300 NMR spectrometer. The center of 1H
decoupling for 31P spectroscopy of hydride complexes was set at ꢀ10 or
ꢀ20 ppm. 1H NMR spectra were referenced to residual solvent
resonances while 31P spectra were referenced to external neat trimethyl
phosphite at δ 140.85 ppm. 15N NMR spectra were reference to external
neat nitromethane at δ 0.00 ppm. Simulations of spectra for cis-
unsymmetrical complexes were performed iteratively using the simula-
tion program NUMMRIT (SpinWorks), and the signs for coupling
constants are not implied. Infrared spectra were recorded on a Shimadzu
8400 series or a Nicolet Avatar 360 FTIR spectrometer as Nujol mulls.
Electrospray mass spectra were recorded on a Finnigan LCQ mass
spectrometer (at the University of Sydney) or carried out at the
Bioanalytical Mass Spectrometry Facility (at the University of New
South Wales). Crystallographic details are given in Table 1.
Preparation oftrans-[FeH(N2H4)(dmpe)2]þ BPh4ꢀ (2t-BPh4).
trans-[FeHCl(dmpe)2] (1t; 0.117 g, 0.297 mmol) was dissolved in a
solution of hydrazine in thf (3 mL, 1 M, 3 mmol) under argon, and the
solution was stirredovernight during which timea yellowsolid precipitated
from solution. Diethyl ether (10 mL) was added, and the yellow solid was
collected by filtration, washed with diethyl ether (10 mL), and dried in
vacuo. A solution of NaBPh4 (0.12 g, 0.35 mmol) in methanol (5 mL) was
added to a solution of the yellow solid in methanol (5 mL) under argon.
The yellow precipitate formed was collected by filtration, washed with
methanol (10 mL, 5 mL), and dried in vacuo (75.4 mg, 36% yield). Anal.
Calcd for C36H57BFeN2P4 (708.38): C, 61.0; H, 8.1; N, 4.0. Found C,
61.2; H, 8.3; N, 3.9%. 1H NMR (thf-d8, 400 MHz): δ 7.27 (m, 8H, o-Ph),
6.86 (m, 8H, m-Ph), 6.72 (m, 4H, p-Ph), 2.78 (m, 2H, FeNH2), 2.34 (bt,
3JHH = 4.2 Hz, 2H, FeNH2NH2), 1.89 (m, 4H, CH2), 1.76 (m, 4H, CH2),
1.43 (bs, 12H, CH3), 1.33 (bs, 12H, CH3), ꢀ29.75 (p, 2JHP = 50.1 Hz, 1H,
FeH). 1H{31P} NMR (thf-d8, 400 MHz): δ 7.27 (m, 8H, o-Ph), 6.86 (m,
8H, m-Ph), 6.72 (m, 4H, p-Ph), 2.78 (bt, 3JHH = 4.2 Hz, 2H, FeNH2), 2.34
(bt, 3JHH = 4.2 Hz, 2H, FeNH2NH2), 1.89 (m, 4H, CH2), 1.76 (m, 4H,
CH2), 1.43 (s, 12H, CH3), 1.33 (s, 12H, CH3), ꢀ29.75 (s, 1H, FeH).
31P{1H} NMR (thf-d8, 162 MHz): δ 67.4 (s). 15N{1H} NMR (thf-d8,
from HN-HSQC, 41 MHz): δꢀ311.0 (corr with 1H δ2.34, FeNH2NH2),
Preparation of trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl). trans-
[FeHCl(dmpe)2] (1t; 33 mg, 84 μmol) was dissolved in a solution of
hydrazine in thf (0.5 mL, 1 M, 0.5 mmol) under nitrogen to give an orange
solution. After standing for 4 days at room temperature, the yellow needles
formed were collected by filtration and dried in vacuo (27 mg, 76% yield),
mp 128ꢀ (dec.). 1H NMR (thf-d8, 600 MHz): δ 4.41 (b, 2H, NH), 2.71 (b,
2H, NH), 2.30 (b, 4H,CH2), 1.66 (bs, 16H, CH2 and CH3), 1.11 (bs, 12H,
2
1
CH3), ꢀ28.9 (p, JHP = 49 Hz, 1H, FeH). 31P{1H} NMR (thf-d8, 243
ꢀ373.2 (corr with H δ 2.78, FeNH2). IR: 3306 w, 3247 w, 3037 w
MHz): δ 68.9 (s). 31P NMR (thf-d8, 202 MHz): δ 68.8 (bd, 2JHP = 49 Hz).
Yellow needles suitable for X-ray crystallography were grown from a similar
solution of 1t in hydrazine, thf, and thf-d8.
(ν(NꢀH)), 1828 m (ν(FeꢀH)), 1596 m, 1578 m, 1422 s, 1300 w, 1283
m, 1231 w, 1144 w, 1065 w, 1034 w, 930 s, 883 m, 848 m, 832 m, 793 w,
733 s, 702 s, 645 s, 624 m, 612 m cmꢀ1
.
The 15N-labeled analogue of 2t-Cl was prepared in situ by dissolving
1t (28 mg, 71 μmol) in a solution of 15N-hydrazine in thf (0.1 mL, 0.5 M,
50 μmol)/thf-d8 (0.4 mL). The solution contained a mixture of 1t
and 15N-labeled 2t-Cl. 15N{1H} NMR (thf/thf-d8, 30 MHz): δ ꢀ311.1
(s, FeNH2NH2), ꢀ371.3 (s, FeNH2).
The 15N-labeled analogue of 2t-BPh4 was prepared by adding a
solution of 15N2-hydrazine in thf (2.6 mL, 0.6 M, 1.6 mmol) to a solution
of 1t (0.107 g, 0.273 mmol) in ethanol (5 mL) under argon. A solution of
NaBPh4 (0.111 g, 0.324 mmol) in ethanol (5 mL) was then added. The
yellow precipitate was collected by filtration, washed with ethanol, and
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1
dried in vacuo (0.101 g, 52% yield). All H and 31P NMR data were
identical to the above except the following. 1H NMR (thf-d8, 400 MHz):
δ 2.79 (bd, 1JHN = 69.4 Hz, 2H, Fe15NH2), 2.34 (dt, 1JHN 63.9 Hz, 3JHH
= 4.7 Hz, 2H, Fe15NH215NH2). 1H{31P} NMR (thf-d8, 400 MHz): δ
thf-d8 (0.1 mL) under argon to give an orange solution. The reaction
mixture was irradiated for 5ꢀ6 h and then left to stand for several days.
The yellow precipitate was collected by filtration and washed with
diethyl ether (5 mL). The solid contained a mixture of cis and trans
isomers in an approximate ratio of 7.8:1 (79 mg, 81% yield). 1H NMR
(thf-d8, 400 MHz): δ 5.04 (br m, 1H, FeNHH), 4.65 (br m, 1H,
FeNHH), 2.98 (m, 2H, NH2), 2.66 (m, 1H, CH2), 2.14 (m, 1H, CH2),
1.99 (d, JHP = 9 Hz, 3H, CH3), 1.92 (d, JHP = 8 Hz, 3H, CH3),
1.87ꢀ1.94 (m, 1H, CH2), 1.78 (d, 2JHP = 7 Hz, 3H, CH3), 1.62ꢀ1.76
(m, 2H, CH2), 1.52 (m, 1H, CH2), 1.48 (d, 2JHP = 6 Hz, 3H, CH3), 1.44
(d, 2JHP = 7 Hz, 3H, CH3), 1.37 (m, 1H, CH2), 1.31 (d, 2JHP = 6 Hz, 3H,
2.79 (dt, 1JHN = 69.4 Hz, 3JHH = 4.7 Hz, 2H, Fe15NH2), 2.34 (dt, 1JHN
=
63.9 Hz, JHH = 4.7 Hz, 2H, Fe15NH215NH2). 15N{1H at 2.5 ppm}
3
NMR (thf-d8, 41 MHz): δ ꢀ311.3 (dp, 1JNN = 6.6 Hz, 3JNP = 1.9 Hz,
Fe15NH215NH2), ꢀ373.4 (dd, JNN = 6.6 Hz, JNꢀhydride = 1.1 Hz,
Fe15NH215NH2). 15N{1H at 2.5, ꢀ30 ppm} NMR (thf-d8, 41 MHz):
δ ꢀ311.3 (dp, 1JNN = 6.6 Hz, 3JNP = 1.9 Hz, Fe15NH215NH2), ꢀ373.4
1
2
2
2
(d, JNN = 6.6 Hz, Fe15NH215NH2). ESI (acetonitrile): m/z 432
1
[5%, FeH(15N2H4)(dmpe)2(CH3CN)þ], 396 [100, Fe(dmpe)2-
(CH3CN)ꢀHþ], 355 [43, Fe(dmpe)2ꢀHþ], 308 [22], 280 [23,
Fe(15N2H4)(dmpe)(CH3CN)ꢀHþ], 219 [30, Fe(CH3CN)4ꢀHþ].
IR: 3352 w, 3300 w, 3236 w, 3160 w, 3043 w (ν(NꢀH)), 2056 w,
1828 m (ν(FeꢀH)), 1592 m, 1578 m, 1422 m, 1300 w, 1282 m, 1231 w,
1138 w, 1065 w, 1034 w, 930 s, 908 m, 884 m, 832 m, 792 w, 732 s, 700 s,
CH3), 1.17(m, 1H, CH2), 1.05(d, 2JHP = 8 Hz, 3H, CH3), 0.97 (d, 2JHP
7 Hz, 3H, CH3), ꢀ11.23 (dddd, 2JHP = 36.7 Hz, 2JHP = 51.8 Hz, 2JHP
=
=
63.3 Hz, JHP = 54.2 Hz, FeH). H{31P} NMR (thf-d8, 400 MHz): δ
5.04 (br m, 1H, FeNHH), 4.65 (br m, 1H, FeNHH), 2.98 (m, 2H,
NH2), 2.66 (m, 1H, CH2), 2.14 (m, 1H, CH2), 1.99 (s, 3H, CH3), 1.92
(s, 3H, CH3), 1.87ꢀ1.94 (m, 1H, CH2), 1.78 (s, 3H, CH3), 1.62ꢀ1.76
(m, 2H, CH2), 1.52 (m, 1H, CH2), 1.48 (s, 3H, CH3), 1.44 (s, 3H,
CH3), 1.37 (m, 1H, CH2), 1.31 (s, 3H, CH3), 1.17 (m, 1H, CH2), 1.05
(s, 3H, CH3), 0.97 (s, 3H, CH3), ꢀ11.23 (s, 1H, FeH). 31P{1H} NMR
(thf-d8, 162 MHz): δ 72.8 (m, 1P, PA), 68.8 (m, 1P, PB), 66.9 (m, 1P,
PC), 57.5 (m, 1P, PD).
2
1
645 m, 612 s cmꢀ1
.
Preparation oftrans-[FeH(NH3)(dmpe)2]þ[BPh4]ꢀ (3-BPh4).
trans-[FeHCl(dmpe)2] (1t; 110 mg, 0.28 mmol) was dissolved in
ammonia saturated ethanol (5 mL) under nitrogen to give a deep orange
solution. After several minutes, a color change to yellow was observed. A
solution of NaBPh4 (120 mg, 0.35 mmol in 5 mL of ammonia saturated
ethanol) was added to the reaction mixture. The precipitate formed was
collected by filtration, washed with ammonia saturated ethanol (3 mL),
and dried invacuo togivea yellow crystalline solid (72mg, 37% yield), mp
208 ꢀC (dec.). Anal. Calcd for C36H56BFeNP4 (693.36): C, 62.4; H, 8.1;
N, 2.0. Found: C, 62.1; H, 8.1; N, 2.0%. 1H NMR (thf-d8, 400 MHz): δ
7.26 (m, 8H, o-Ph), 6.86 (m, 8H, m-Ph), 6.71 (m, 4H, p-Ph), 1.78 (m,
8H, CH2), 1.34 (bs, 12H, CH3), 1.30 (bs, 12H, CH3), ꢀ0.09 (b, 3H,
FeNH3), ꢀ30.08 (p, 2JHP = 49.5 Hz, 1H, FeH). 1H{31P} NMR (thf-d8,
400 MHz): δ 7.26 (m, 8H, o-Ph), 6.86 (m, 8H, m-Ph), 6.71 (m, 4H,
p-Ph), 1.78 (m, 8H, CH2), 1.34 (s, 12H, CH3), 1.30 (s, 12H, CH3),
ꢀ0.09 (b, 3H, FeNH3), ꢀ30.08 (s, 1H, FeH). 31P{1H} NMR (thf-d8, 162
MHz): δ 69.0 (s). 15N{1H} NMR (thf-d8, 41 MHz, from HN-HSQC):
The 15N-labeled analogue of 2c-Cl was prepared in situ by allowing a
solution of 1t (33 mg, 84 μmol) in 15N2-hydrazine in thf (0.3 mL, 0.5 M,
0.15 mmol)/thf-d8 (0.1 mL) to stand for 1 month. The solution
contained a mixture of 1t, 15N-labeled 2t-Cl, and 15N-labeled 2c-Cl in
an approximate ratio of 29:3:1. 15N{1H} NMR (thf/thf-d8, 30 MHz):
δ ꢀ298.0 (s, FeNH2NH2), ꢀ377.6 (s, FeNH2).
Preparation of cis- and trans-[FeH(N2H3)(dmpe)2] (4c and
4t). A suspension of trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl; 30.8 mg,
72.5 μmol) and KOtBu (30.4 mg, 0.271 mmol) in tetrahydrofuran
(0.5 mL) was shaken under argon for several minutes; then the solvent
was removed under reduced pressure. Benzene-d6 was added by vacuum
transfer to the residue to afford a dark orange solution.
Compound 4c. 1H NMR (benzene-d6, 400 MHz): δ 1.89 (d, 2JHP = 8
Hz, 3H, CH3), 1.72 (d, 2JHP = 8 Hz, 3H, CH3), 1.23 (d, 2JHP = 6 Hz, 3H,
CH3), 1.18 (d, 2JHP = 5 Hz, 3H, CH3), 0.93 (d, 2JHP = 7 Hz, 3H, CH3),
0.89 (d, 2JHꢀP = 7 Hz, 3H, CH3), 0.87 (d, 2JHP = 5 Hz, 3H, CH3), 0.61
1
δ ꢀ433.1 (corr with H δ ꢀ0.09, FeNH3). ESI (acetonitrile): m/z
415 [98%, FeH(NH3)(dmpe)2(CH3CN)þ], 398 [70, FeH(dmpe)2-
(CH3CN)þ], 357 [100, FeH(dmpe)2þ], 265 [80, FeH(NH3)(dmpe)-
(CH3CN)þ], 248 [54, FeH(dmpe)(CH3CN)þ]. IR: 3354 w, 3281 w,
3048 m, 3032 m (ν(NꢀH)), 1836 (ν(FeꢀH)), 1579 w, 1422 s, 1304 w,
1297 m, 1286 m, 1263 m, 1179 w, 1157 w, 1121 w, 1066 w, 1032 w, 997 w,
929 s, 909 m, 886 s, 866 w, 846 m, 834 m, 805 w, 793 w, 753 w, 730 m, 704
2
(d, JHP = 5 Hz, 3H, CH3), ꢀ11.27 (m, FeH) (CH2 resonances
obscured by overlapping signals). 1H{31P} NMR (benzene-d6, 400
MHz): δ 1.89 (s, 3H, CH3), 1.72 (s, 3H, CH3), 1.23 (s, 3H, CH3),
1.18 (s, 3H, CH3), 0.93 (s, 3H, CH3), 0.89 (s, 3H, CH3), 0.87 (s, 3H,
CH3), 0.61 (s, 3H, CH3), ꢀ11.27 (s, FeH) (CH2 resonances obscured
by overlapping signals). 31P{1H} NMR (benzene-d6, 162 MHz): δ 72.5
(m, 1P), 70.3 (m, 1P), 66.0 (m, 1P), 59.6 (m, 1P).
s, 644 m, 611 m cmꢀ1
.
[FeH(15NH3)(dmpe)2]þ[BPh4]ꢀ (3t-BPh4) was observed on al-
lowing [FeH(15N2H4)(dmpe)2]þ[BPh4]ꢀ (2t-BPh4) to stand in thf-d8
solution. All 1H and 31P NMR data were identical to the above except
the following: 1H NMR (thf-d8, 400 MHz): δ ꢀ0.10 (dp, 1JHN 65.5 Hz,
3JHP = 2.9 Hz, Fe15NH3). 15N{1H} (thf-d8, 41 MHz): δ ꢀ433.7 (s).
Preparation of cis-[FeH(N2H4)(dmpe)2]þClꢀ (2c-Cl). trans-
[FeHCl(dmpe)2] (18 mg, 46 μmol) was dissolved in a solution of
hydrazine in thf (0.3 mL, 1 M, 0.3 mmol) and thf-d8 (0.1 mL) under
nitrogen to give an orange solution. After 2 days, yellow needles of
trans-[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl) were formed. After 2.5
months, the yellow needles had re-dissolved and new prismatic crystals
of cis-[FeH(N2H4)(dmpe)2]þClꢀ (2c-Cl) formed and these were
suitable for X-ray crystal analysis. The solution contained a mixture of
1t, 2t-Cl, and 2c-Cl in an approximate ratio of 1.5:1:9. 1H NMR (thf/thf-
d8, 300 MHz, high fieldonly): δ ꢀ11.2 (dddd, 2JHP = 36.7 Hz, 2JHP = 51.8
Hz, 2JHP = 64.6 Hz, 2JHP = 53.0 Hz, FeH). 31P{1H} NMR(thf/thf-d8, 121
MHz): δ 73.2 (ddd, 2JP P = 17.6 Hz, 2JP P = 39.2 Hz, 2JP P = 29.2 Hz,
Compound 4t. 1HNMR(benzene-d6, 400MHz):δ1.76 (m, 4H, CH2),
1.42 (m, 4H, CH2), 1.38 (bs, 12H, CH3), 1.13 (bs, 12H, CH3), ꢀ26.05 (p,
2JHP = 46 Hz, FeH). 1H{31P} NMR (benzene-d6, 400 MHz): δ 1.76 (m,
4H, CH2), 1.42 (m, 4H, CH2), 1.38 (s, 12H, CH3), 1.13 (s, 12H, CH3),
ꢀ26.05 (s, FeH). 31P{1H} NMR (benzene-d6, 162 MHz): δ 72.0 (s).
The 15N-labeled analogues of 4c and 4t were prepared similarly by
reaction of 15N-labeled 2t-Cl (13 mg, 30 μmol) and KOtBu (21 mg, 0.19
mmol) in tetrahydrofuran (2 mL) and extraction with pentane (7 mL).
Compound 4c. 1H NMR (toluene-d8, 400 MHz): δ 1.90 (d, 2JHP = 8
Hz, 3H, CH3), 1.72 (d, 2JHP = 8 Hz, 3H, CH3), 1.23 (d, 2JHP = 6 Hz, 3H,
CH3), 1.19 (d, 2JHP = 5 Hz, 3H, CH3), 0.91 (d, 2JHP = 7 Hz, 3H, CH3),
0.90 (d, 2JHP = 5 Hz, 3H, CH3), 0.87 (d, 2JHP = 6 Hz, 3H, CH3), 0.64 (d,
2JHP = 6 Hz, 3H, CH3), ꢀ11.39 (m, FeH) (CH2 resonances obscured by
overlapping signals). 1H{31P} NMR (toluene-d8, 400 MHz): δ 1.90 (s,
3H, CH3), 1.72 (s, 3H, CH3), 1.23 (s, 3H, CH3), 1.19 (s, 3H, CH3), 0.91
(s, 3H, CH3), 0.90 (s, 3H, CH3), 0.87 (s, 3H, CH3), 0.64 (s, 3H, CH3),
ꢀ11.39 (s, FeH) (CH2 resonances obscured by overlapping signals).
31P{1H} NMR (toluene-d8, 162 MHz): δ 72.5 (m, 1P), 70.6 (m, 1P),
66.3 (m, 1P), 59.4 (m, 1P).
A
B
A
C
A D
1P, PA), 69.4 (ddd, JP P = 101.3 Hz, 2JP P = 38.5 Hz, 1P, PB), 68.1
2
(ddd, 2JP P = 25.4 Hz,B1P, PC), 57.4 (dddB, 1P, PD).
C
D
AlternCative synthesis: Compound 1t (90.7 mg, 0.231 mmol) was
D
dissolved in a solution of hydrazine in thf (0.8 mL, 1 M, 0.8 mmol) and
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Compound 4t: 1HNMR(toluene-d8, 400 MHz): δ1.97 (m, 4H, CH2),
1.43 (bs, 12H, CH3), 1.33 (m, 4H, CH2), 1.00 (bs, 12H, CH3), ꢀ27.66 (p,
2JHꢀP = 48 Hz, FeH). 1H{31P} NMR (toluene-d8, 400 MHz): δ 1.97 (m,
4H, CH2), 1.43 (s, 12H, CH3), 1.33 (m, 4H, CH2), 1.00 (s, 12H, CH3),
ꢀ27.66 (s, FeH). 31P{1H} NMR (toluene-d8, 162 MHz): δ 70.0 (s).
Compounds 4c/4t. 15N{1H} NMR (toluene-d8, 41 MHz, 198K): δ
ꢀ275.9 (m), ꢀ308.8 (m), ꢀ369.6 (b), ꢀ378.4 (b). 15N NMR (toluene-
d8, 41 MHz, 198 K): δꢀ275.9 (m), ꢀ308.8 (m), ꢀ369.6(b), ꢀ378.4 (b).
Preparation of trans-[RuH(N2H4)(dmpe)2]þClꢀ (6t-Cl).
trans-[RuHCl(dmpe)2] (5t; 26.9 mg, 61.4 μmol) was dissolved in a
solution of hydrazine in thf (0.3 mL, 1 M, 0.3 mmol) and thf-d8 (0.2 mL)
under argon to give a nearly colorless solution. After standing for 3 days
at room temperature, the fine colorless needles of trans-[RuH(N2H4)-
(dmpe)2]þClꢀ formed were collected by filtration under nitrogen and
(s, 1H, RuH). 31P{1H} NMR (thf-d8, 162 MHz): δ 56.3 (ddd, 2JP P
=
=
A
B
23.2 Hz, 2JP P = 28.3 Hz, 2JP P = 13.6 Hz, 1P, PA), 48.3 (ddd, 2JP P
C
A D
304.5 Hz, 2JPA P = 23.7 Hz, 1P, PB), 38.6 (ddd, 2JP P = 14.5 Hz, 1P,BPCC),
27.3 (ddd, 1P, DPD).
B
C D
Preparation of cis-[RuH(N2H4)(dmpe)2]þClꢀ (6c-Cl). A solu-
tion of 5c in thf-d8 as prepared above was treated with a solution of
hydrazine (0.5 mL, 1 M, 0.5 mmol) under argon. After standing for
approximately 1 month, colorless crystals of 6c-Cl formed and were
collected by filtration and washed with hexane (3 ꢁ 1 mL; 8 mg, 24%
yield). 1H NMR (thf-d8, 500 MHz):δ 6.15 (bm, 1H, RuNHH), 5.53 (bm,
1H, RuNHH), 3.26 (br, 2H, NH2), 2.50 (m, 2H, CH2), 2.00 (m, 1H,
CH2), 1.97 (d, 2JHP = 8 Hz, 3H, CH3), 1.92 (d, 2JHP = 7 Hz, 3H, CH3),
1.79ꢀ1.87 (m, 2H, CH2), 1.75 (d, 2JHP = 7 Hz, 3H, CH3), 1.58ꢀ1.66 (m,
1H, CH2), 1.51 (d, 2JHP = 6 Hz, 3H, CH3), 1.47 (d, 2JHP = 7 Hz, 3H,
CH3), 1.30 (d, 2JHP = 6 Hz, 3H, CH3), 1.26ꢀ1.18 (m, 2H, CH2), 1.20 (d,
2JHꢀP = 8 Hz, 3H, CH3), 1.16 (d, 2JHP = 7 Hz, 3H, CH3), ꢀ8.33 (dm, 2
1
washed with diethyl ether (4 ꢁ 1 mL; 24 mg, 83% yield). H NMR
2
(MeOH, 500 MHz, high field only): δ ꢀ20.1 (p, JHP = 21 Hz, 1H,
JHP = 86.1 Hz, RuH). 1H{31P} NMR(thf-d8, 500 MHz):δ6.15(d, 2JHH
=
RuH). 31P{1H} NMR (MeOH, 202 MHz): δ 41.1 (s).
11.5 Hz, 1H, RuNHH), 5.53 (d, 2JHH = 11.5 Hz, 1H, RuNHH), 3.26 (br,
2H, NH2), 2.50 (m, 2H, CH2), 2.00 (m, 1H, CH2), 1.97 (s, 3H, CH3),
1.92 (s, 3H, CH3), 1.79ꢀ1.87 (m, 2H, CH2), 1.75 (s, 3H, CH3),
1.58ꢀ1.66 (m, 1H, CH2), 1.51 (s, 3H, CH3), 1.47 (s, 3H, CH3), 1.30
(s, 3H, CH3), 1.18ꢀ1.26 (m, 2H, CH2), 1.20 (s, 3H, CH3), 1.16 (s, 3H,
CH3), ꢀ8.33 (s, 1H, RuH). 31P{1H} NMR(thf-d8, 202 MHz): δ 49.6 (m,
1P, PA), 42.3 (m, 1P, PB), 39.9 (m, 1P, PC), 31.3 (m, 1P, PD).
The 15N-labeled analogue of 6t-Cl was prepared in situ by allowing a
solution of 5t and 5c in 15N2-hydrazine in thf and thf-d8 to stand for
several days. The solution contained a mixture of 5t, 5c, 15N-labeled 6t-
Cl, and 15N-labeled 6c-Cl in an approximate ratio of 2.4:6.8:1:4.2.
15N{31P, 1H} NMR (thf/thf-d8, 51 MHz): δ ꢀ309.7 (d, 1JNN = 6.1 Hz,
RuNH2NH2), ꢀ370.5 (d, RuNH2). 15N{1H} NMR (thf/thf-d8, 51
1
3
MHz): δ ꢀ309.7 (dp, JNN = 6.1 Hz, JNP = 1.6 Hz, RuNH2NH2),
ꢀ370.5 (d, RuNH2). 15N NMR (thf/thf-d8, 51 MHz): δ ꢀ309.7 (bt,
1JNH = 60 Hz, RuNH2NH2), ꢀ370.5 (bt, 1JNH 70 Hz, RuNH2).
The 15N-labeled analogue of 6c-Cl was prepared in situ by allowing a
solution 5t and 5c in 15N2-hydrazine in thf and thf-d8 to stand for several
days. The solution contained a mixture of 5t, 5c, 15N-labeled 6t-Cl, and
15N-labeled 6c-Cl in an approximate ratio of 2.4:6.8:1:4.2. 15N{31P, 1H}
NMR (thf/thf-d8, 51 MHz): δ ꢀ298.4 (d, 1JNN = 4.6 Hz, RuNH2NH2),
ꢀ374.2 (d, RuNH2). 15N{1H} NMR (thf/thf-d8, 51 MHz): δ ꢀ298.4
ꢀ
Preparation of trans-[RuH(N2H4)(dmpe)2]þ BPh4 (6t-
BPh4). Compound 5t (29.8 mg, 68.1 μmol) was dissolved in a solution
of hydrazine in thf (0.4 mL, 1 M, 0.4 mmol) and thf-d8 (0.25 mL) under
argon. The white solid formed was collected by filtration under nitrogen
and washed with diethyl ether (3 ꢁ 1 mL). A solution of NaBPh4 (27
mg, 79 μmol) in methanol (1 mL) was added to a solution of the white
solid in methanol (0.5 mL). Compound 6t-BPh4 was formed as a white
solid which was collected by filtration, washed with methanol (2 ꢁ
0.5 mL), and dried in vacuo (36 mg, 70% yield). Anal. Calcd for
C36H57BN2P4Ru (753.71): C, 57.4; H, 7.6; N, 3.7. Found: C, 57.4; H,
7.5; N, 3.4%. 1H NMR (thf-d8, 500 MHz): δ 7.27 (m, 8H, o-Ph), 6.86
(m, 8H, m-Ph), 6.72 (m, 4H, p-Ph), 3.42 (br, 2H, RuNH2), 2.64 (b, 2H,
RuNH2NH2), 1.57ꢀ1.77 (m, 8H, CH2), 1.40 (bs, 24H, CH3), ꢀ20.56
(p, 2JHP = 22 Hz, 1H, RuH). 1H{31P} NMR (thf-d8, 500 MHz): δ 7.27
(m, 8H, o-Ph), 6.86 (m, 8H, m-Ph), 6.72 (m, 4H, p-Ph), 3.42 (br, 2H,
RuNH2), 2.64 (b, 2H, RuNH2NH2), 1.71 (m, 4H, CH2), 1.63 (m, 4H,
CH2), 1.40 (bs, 24H, CH3), ꢀ20.56 (s, 1H, RuH). 31P{1H} NMR (thf-
d8, 202 MHz): δ 41.1 (s). 15N{1H} NMR (thf-d8, from HN-HSQC, 41
MHz): δ ꢀ310.1 (corr with 1H δ 2.64, RuNH2NH2), ꢀ372.9 (corr with
1H δ 3.42, RuNH2). ESI (acetonitrile): m/z 444.08 [20%, RuH-
(dmpe)2(CH3CN)þ], 435.05 [20, RuH(N2H4)(dmpe)2þ], 403.06
[20, RuH(dmpe)2þ]. IR: 3367 w, 3322 w, 3257 w (ν(NꢀH)), 1929 s
(ν(RuꢀH)), 1596 m, 1578 m, 1422 s, 1299 w, 1284 m, 1134 w, 1081 w,
1034 w, 933 s, 910 m, 887 m, 835 m, 794 w, 734 s, 702 s, 648 s,
613 s cmꢀ1. Crystals suitable for X-ray crystallography were grown from
a solution of 6t-Cl and NaBPh4 in methanol.
(dd, 1JNN = 4.6 Hz, 3JNP = 4.6 Hz, RuNH2NH2), ꢀ374.2 (ddt, 3JNP
=
3
25.3 Hz, JNP = 1.9 Hz, RuNH2). 15N NMR (thf/thf-d8, 51 MHz): δ
ꢀ298.4 (t, 1JNH = 64.3 Hz, RuNH2NH2), ꢀ374.2 (td, 1JNH = 71.5 Hz,
3JNP = 25.3 Hz, RuNH2).
Preparation of trans-[RuH(N2H3)(dmpe)2] (7t). A suspension
of 6t-Cl (31 mg, 66 μmol) and KOtBu (32 mg, 0.29 mmol) in
tetrahydrofuran (1 mL) was stirred under nitrogen for several minutes;
then the solvent was removed under reduced pressure. The residue was
extracted with pentane (6 mL), filtered through Celite, and the filtrate
evaporated to dryness under reduced pressure to afford 7t as an off-white
solid. 1H NMR (benzene-d6, 300 MHz): δ 5.77 (b, NH), 1.89 (m, 4H,
CH2), 1.44 (bs, 12H, CH3), 1.17 (m, 4H, CH2), 1.02 (bs, 12H, CH3),
2
1
ꢀ19.33 (p, JHP = 21.7 Hz, RuH). H{31P} NMR (benzene-d6, 300
MHz): δ 5.76 (b, NH), 1.89 (m, 4H, CH2), 1.44 (s, 12H, CH3), 1.17 (m,
4H, CH2), 1.02 (s, 12H, CH3), ꢀ19.33 (s, RuH). 31P{1H} NMR
(benzene-d6, 122 MHz): δ 42.0 (s).
The 15N-labeled analogue of 7t was prepared similarly by reaction of
15N-labeled 6t-Cl (28 mg, 59 μmol) and KOtBu (28 mg, 0.25 mmol) in
tetrahydrofuran (2 mL) and extraction with hexane (6 mL). 1H NMR
(benzene-d6, 400 MHz): δ 5.54 (b, NH), 1.93 (m, 4H, CH2), 1.44 (bs,
12H, CH3), 1.17 (m, 4H, CH2), 1.02 (bs, 12H, CH3), ꢀ19.28 (dp, 2JHP
21.7 Hz, 2JHꢀN 8.1 Hz, RuH). 1H{31P} NMR (benzene-d6, 400 MHz):
δ 5.54 (b, NH), 1.93 (m, 4H, CH2), 1.44 (s, 12H, CH3), 1.17 (m, 4H,
CH2), 1.02 (s, 12H, CH3), ꢀ19.28 (d, 2JHN = 8.1 Hz, RuH). 31P{1H}
NMR (benzene-d6, 162 MHz): δ 42.0 (s). 15N{1H} NMR (benzene-d6,
41 MHz): δ ꢀ306.8 (s), ꢀ365.7 (bs). 15N NMR (benzene-d6, 41
MHz): δ ꢀ306.8 (s), ꢀ365.9 (bs).
Preparation of cis-[RuHCl(dmpe)2] (5c). A solution of 5t (31.5
mg, 71.9 μmol) in thf-d8 (0.5 mL) was irradiated for 2 h under argon.
The solution contained a mixture of the cis and trans isomers in an
approximate ratio of 5.7:1. 1H NMR (thf-d8, 400 MHz): δ 1.61ꢀ1.82
(m, 4H, CH2), 1.56 (m, 6H, CH3), 1.46ꢀ1.59 (m, 2H, CH2), 1.41 (m,
6H, CH3), 1.32 (d, 2JHP = 7 Hz, 3H, CH3), 1.23ꢀ1.39 (m, 2H, CH2),
1.26 (d, 2JHP = 6 Hz, 6H, CH3), 1.15 (d, 2JHP = 8 Hz, 3H, CH3), ꢀ8.52
(dddd, 2JHP = 104.0 Hz, 2JHP = 22.0 Hz, 2JHP = 30.7 Hz, 2JHP = 24.3 Hz,
’ ASSOCIATED CONTENT
1
1H, RuH). H{31P} NMR (thf-d8, 400 MHz): δ 1.64ꢀ1.76 (m, 4H,
S
Supporting Information. Crystallographic data for trans-
b
CH2), 1.57 (s, 3H, CH3), 1.55 (s, 3H, CH3), 1.46ꢀ1.59 (m, 2H, CH2),
1.42 (s, 3H, CH3), 1.41 (s, 3H, CH3), 1.32 (d, 2JHP = 7 Hz, 3H, CH3),
1.23ꢀ1.39 (m, 2H, CH2), 1.26 (s, 6H, CH3), 1.15 (s, 3H, CH3), ꢀ8.52
[FeH(N2H4)(dmpe)2]þClꢀ (2t-Cl), cis-[FeH(N2H4)(dmpe)2]þ-
Clꢀ (2c-Cl), and trans-[RuH(N2H41)(dmpe)2]þBPh4ꢀ (6t-BPh4)
(cif), and figures showing selected H, 31P{1H} (cif) and figures
5475
dx.doi.org/10.1021/ic102519f |Inorg. Chem. 2011, 50, 5468–5476

Inorganic Chemistry
ARTICLE
showing 15N{1H} NMR spectra for complexes cis-[FeH(N2H3)-
(dmpe)2] (4c), trans-[FeH(N2H3)(dmpe)2] (4t), andtrans-[RuH-
(N2H3)(dmpe)2] (7t) (pdf). This material is available free of charge
via the Internet at http://pubs.acs.org.
(15) Saouma, C. T.; M€uller, P.; Peters, J. C. J. Am. Chem. Soc. 2009,
131, 10358.
(16) Hills, A.; Hughes, D. L.; Jimenez-Tenorio, M.; Leigh, G. J.
J. Organomet. Chem. 1990, 391, C41.
(17) Heaton, B. T.; Jacob, C.; Page, P. Coord. Chem. Rev. 1996,
154, 193.
(18) Field, L. D.; Li, H. L.; Dalgarno, S. J. Inorg. Chem. 2010,
’ AUTHOR INFORMATION
49, 6214.
Corresponding Author
*E-mail: L.Field@unsw.edu.au.
(19) Field, L. D.; Hazari, N.; Li, H. L.; Luck, I. J. Magn. Reson. Chem.
2003, 41, 703.
(20) (a) Schrock, R. R.; Glassman, T. E.; Vale, M. G. J. Am. Chem.
Soc. 1991, 113, 725. (b) Glassman, T. E.; Vale, M. G.; Schrock, R. R.
Organometallics 1991, 10, 4046. (c) Block, E.; Ofori-Okai, G.; Kang, H.;
Zubieta, J. J. Am. Chem. Soc. 1992, 114, 758. (d) Schrock, R. R.;
Glassman, T. E.; Vale, M. G.; Kol, M. J. Am. Chem. Soc. 1993,
115, 1760. (e) Schrock, R. R.; Vale, M. G. Inorg. Chem. 1993,
32, 2767. (f) Coucouvanis, D.; Mosier, P. E.; Demadis, K. D.; Patton,
S.; Malinak, S. M.; Kim, C. G.; Tyson, M. A. J. Am. Chem. Soc. 1993,
115, 12193. (g) Kuwata, S.; Mizobe, T.; Hidai, M. Inorg. Chem. 1994,
33, 3619. (h) Schollhammer, P.; Petillon, F. Y.; Poder-Guillou, S.;
Saillard, J. Y.; Talarmin, J.; Muir, K. W. Chem. 1996, 2633. (i) Hitchcock,
P. B.; Hughes, D. L.; Maguire, M. J.; Marjani, K.; Richards, R. L. J. Chem.
Soc., Dalton Trans. 1997, 4747. (j) Nakajima, Y.; Inagaki, A.; Suzuki, H.
Organometallics 2004, 23, 4040. (k) Takei, I.; Dohki, K.; Kobayashi, K.;
Suzuki, T.; Hidai, M. Inorg. Chem. 2005, 44, 3768.
’ ACKNOWLEDGMENT
We gratefully acknowledge financial support from the Australian
Research Council.
’ REFERENCES
(1) Crossland, J. L.; Tyler, D. R. Coord. Chem. Rev. 2010, 254, 1883.
(2) Maxwell, G. R. Synthetic Nitrogen Products, A Practical Guide to
the Products and Processes; Kluwer: New York, 2004.
(3) See for example: Sellmann, D.; Kappler, J.; Moll, M.; Knoch, F.
Inorg. Chem. 1993, 32, 960.
(4) (a) Igarashi, R. Y.; Laryukhin, M.; Dos Santos, P. C.; Lee, H.-I.;
Dean, D. R.; Seefeldt, L. C.; Hoffman, B. M. J. Am. Chem. Soc. 2005,
127, 6231. (b) Leigh, G. J. Eur. J. Biochem. 1995, 229, 14. (c) Eady, R. R.;
Leigh, G. J. J. Chem. Soc., Dalton Trans. 1994, 2739.
(5) Barney, B. M.; Yang, T.-C.; Igarashi, R. Y.; Dos Santos, P. C.;
Laryukhin, M.; Lee, H.-I.; Hoffman, B. M.; Dean, D. R.; Seefeldt, L. C.
J. Am. Chem. Soc. 2005, 127, 14960.
(21) Fox, D. J.; Bergman, R. G. Organometallics 2004, 23, 1656.
(22) Field, L. D.; Li, H. L.; Magill, A. M. Inorg. Chem. 2009, 48, 5.
(23) Fox, D. J.; Bergman, R. G. J. Am. Chem. Soc. 2003, 125, 8984.
(24) Crossland, J. L.; Balesdent, C. G.; Tyler, D. R. Dalton Trans.
2009, 4420.
(25) (a) McCleverty, J. A.; Rae, A. E.; Wolochowicz, I.; Bailey, N. A.;
Smith, J. M. A. J. Chem. Soc., Dalton Trans. 1983, 71. (b) Murray, R. C.;
Schrock, R. R. J. Am. Chem. Soc. 1985, 107, 4557. (c) Latham, I. A.; Leigh,
G. J. J. Chem. Soc., Dalton Trans. 1986, 399. (d) Schrock, R. R.; Liu, A. H.;
O’Regan, M. B.; Finch, W. C.; Payack, J. F. Inorg. Chem. 1988, 27, 3574.
(e) Shapiro, P. J.; Henling, L. M.; Marsh, R. E.; Bercaw, J. E. Inorg. Chem.
1990, 29, 4560. (f) Sellmann, D.; Kern, W.; P€ohlmann, G.; Knoch, F.;
Moll, M. Inorg. Chim. Acta 1991, 185, 155.
(26) (a) Mashima, K.; Kaneyoshi, H.; Kaneko, S.; Tani, K.; Nakamura,
A. Chem. Lett. 1997, 569. (b) Sellmann, D.; Engl, K.; Heinemann, F. W.;
Sieler, J. Eur. J. Inorg. Chem. 2000, 1079. (c) Zhang, Q.-F.; Zheng, H.; Wong,
W.-Y.; Wong, W.-T.; Leung, W.-H. Inorg. Chem. 2000, 39, 5255.
(d) Takemoto, S.; Kawamura, H.; Yamada, Y.; Okada, T.; Ono, A.;
Yoshikawa, E.; Mizobe, Y.; Hidai, M. Organometallics 2002, 21, 3897.
(e) Sellmann, D.; Hille, A.; Rosler, A.; Heinemann, F. W.; Moll, M. Inorg.
Chim. Acta 2004, 357, 3336. (f) Sellmann, D.; Hille, A.; Rosler, A.;
Heinemann, F. W.; Moll, M.; Brehm, G.; Schneider, S.; Reihar, M.; Hess,
B. A.; Bauer, W. Chem.—Eur. J. 2004, 10, 819.
(6) (a) Hough, J. J.; Singleton, E. J. Chem. Soc., Chem. Commun.
1972, 371. (b) Ashworth, T. V.; Singleton, E.; Hough, J. J. J. Chem. Soc.,
Dalton Trans. 1977, 1809. (c) Xu, W.; Lough, A. J.; Morris, R. H. Inorg.
Chem. 1996, 35, 1549. (d) Xu, W.; Lough, A. J.; Morris, R. H. Can. J.
Chem. 1997, 75, 475. (e) Albertin, G.; Antoniutti, S.; Bacchi, A.;
Bordignon, E.; Dolcetti, P. M.; Pelizzi, G. J. Chem. Soc., Dalton Trans.
1997, 4435. (f) Albertin, G.; Antoniutti, S.; Bacchi, A.; Bergamo, M.;
Bordignon, E.; Pelizzi, G. Inorg. Chem. 1998, 37, 479. (g) Albertin, G.;
Antoniutti, S.; Bordignon, E.; Menegazzo, F. J. Chem. Soc., Dalton Trans.
2000, 1181. (h) Albertin, G.; Antoniutti, S.; Bacchi, A.; Fregolent, B.;
Pelizzi, G. Eur. J. Inorg. Chem. 2004, 1922.
(7) Albertin, G.; Antoniutti, S.; Bordignon, E.; Pattaro, S. J. Chem.
Soc., Dalton Trans. 1997, 4445.
(8) (a) Leigh, G. J.; Jimenez-Tenorio, M. J. Am. Chem. Soc. 1991,
113, 5862. (b) Hills, A.; Hughes, D. L.; Jimenez-Tenorio, M.; Leigh,
G. J.; Rowley, A. T. J. Chem. Soc., Dalton Trans. 1993, 3041. (c) Hall,
D. A.; Leigh, G. J. J. Chem. Soc., Dalton Trans. 1996, 3539.
(9) Gilbertson, J. D.; Szymczak, N. K.; Tyler, D. R. J. Am. Chem. Soc.
2005, 127, 10184.
(27) Kaplan, A. W.; Ritter, J. C. M.; Bergman, R. G. J. Am. Chem. Soc.
1998, 120, 6828.
(10) Yelle, R. B.; Crossland, J. L.; Szymczak, N. K.; Tyler, D. R. Inorg.
Chem. 2009, 48, 861.
(28) (a) Jenke, T.; Stoeckli-Evans, H.; S€uss-Fink, G. J. Organomet.
Chem. 1990, 391, 395. (b) Jahncke, M.; Neels, A.; Stoeckli-Evans, H.;
S€uss-Fink, G. J. Organomet. Chem. 1998, 565, 97. (c) Takei, I.; Dohki, K.;
Kobayashi, K.; Suzuki, T.; Hidai, M. Inorg. Chem. 2005, 44, 3768.
(29) (a) Glassman, T. E.; Vale, M. G.; Schrock, R. R. J. Am. Chem.
Soc. 1992, 114, 8098. (b) Smith, M. R.; Cheng, T. Y.; Hillhouse, G. L.
J. Am. Chem. Soc. 1993, 115, 8638.
(30) (a) Baker, M. V.; Field, L. D. J. Organomet. Chem. 1988,
354, 351. (b) Baker, M. V.; Field, L. D. J. Chem. Soc., Chem. Commun.
1988, 546.
(11) (a) Zdilla, M. J.; Verma, A. K.; Lee, S. C. Inorg. Chem. 2008,
47, 11382. (b) Yu, Y.; Brennessel, W. W.; Holland, P. L. Organometallics
2007, 26, 3217. (c) Rath, S. P.; Olmstead, M. M.; Balch, A. L. Inorg.
Chem. 2004, 43, 6357. (d) Sellmann, D.; Shaban, S. Y.; Heinemann,
F. W. Eur. J. Inorg. Chem. 2004, 4591. (e) Sellmann, D.; Friedrich, H.;
Knoch, F. Z. Naturforsch., B: J. Chem. Sci. 1994, 49, 660. (f) Sellmann, D.;
Soglowek, W.; Knoch, F.; Ritter, G.; Dengler, J. Inorg. Chem. 1992,
31, 3711. (g) Casey, M. T.; Guinan, P.; Canavan, A.; McCann, M.;
Cardin, C.; Kelly, N. B. Polyhedron 1991, 10, 483. (h) Goedken, V. L.;
Peng, S.-M.; Molin-Norris, J.; Park, Y. J. Am. Chem. Soc. 1976, 98, 8391.
(12) Sellmann, D.; Blum, N.; Heinemann, F. W. Z. Naturforsch., B:
J. Chem. Sci. 2001, 56, 581.
(13) Field, L. D.; Li, H. L.; Dalgarno, S. J.; Turner, P. Chem.
Commun. 2008, 1680.
(14) (a) Crossland, J. L.; Zakharov, L. N.; Tyler, D. R. Inorg. Chem.
2007, 46, 10476. (b) Sellmann, D.; Kreutzer, P.; Huttner, G.; Frank, A.
Z. Naturforsch., B: J. Chem. Sci. 1978, 33, 1341.
5476
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