Iridium(III)-(hydrido)cyclometallated-imine complexes and metal-promoted hydrolytic cleavage of imines

Article abstract of DOI:10.1023/B:RUCB.0000019891.73897.e4

The room temperature reaction of the complex cis,trans,cis-[Ir(H) ₂(PPh₃)₂(Solv)₂]PF₆ (Solv is a solvent) with the imine PhCH₂N=CHPh in acetone generates (with loss of H₂) the orthometallated complex [Ir(H){PhCH ₂N=CH(o-C₆H₄)}(PPh₃) ₂(Me₂CO)]PF₆ (3) containing a five-membered cyclometallated imine moiety. In MeOH, the reaction at an imine:Ir ratio = 1 leads to the corresponding MeOH analog of 3, while with excess imine, the mixed orthometallated imine/bezylamine complex [Ir(H){PhCH₂N=CH(o-C ₆H₄)}(PPh₃)₂(PhCH₂NH ₂)]PF₆ (4) is formed; the source of the coordinated amine is an Ir-promoted hydrolysis of the imine, the water likely coming from imine. Complexes 3 and 4 are fully characterized by elemental analysis, ¹H and ³¹P{¹H} NMR spectroscopy, and X-ray crystal structure analysis.

Full text of DOI:10.1023/B:RUCB.0000019891.73897.e4

Russian Chemical Bulletin, International Edition, Vol. 52, No. 12, pp. 2715—2721, December, 2003
2715
Iridium(III)ꢀ(hydrido)cyclometallatedꢀimine complexes and metalꢀpromoted
hydrolytic cleavage of imines*
P. Marcazzan, B. O. Patrick, and B. R. Jamesꢀ
Department of Chemistry, The University of British Columbia,
2036 Main Mall, Vancouver, B. C. V6T 1Z1, Canada.
Fax: +1 (604) 822 2847. Eꢀmail: brj@chem.ubc.ca
The room temperature reaction of the complex cis,trans,cisꢀ[Ir(H)2(PPh3)2(Solv)2]PF6
(Solv is a solvent) with the imine PhCH2N=CHPh in acetone generates (with loss of H2)
the orthometallated complex [Ir(H){PhCH2N=CH(oꢀC6H4)}(PPh3)2(Me2CO)]PF6 (3)
containing a fiveꢀmembered cyclometallated imine moiety. In MeOH, the reaction at an
imine : Ir ratio = 1 leads to the corresponding MeOH analog of 3, while with excess imine,
the mixed orthometallated imine/bezylamine complex [Ir(H){PhCH2N=CH(oꢀ
C6H4)}(PPh3)2(PhCH2NH2)]PF6 (4) is formed; the source of the coordinated amine is an
Irꢀpromoted hydrolysis of the imine, the water likely coming from imine. Complexes 3 and 4
1
are fully characterized by elemental analysis, H and 31P{1H} NMR spectroscopy, and Xꢀray
crystal structure analysis.
Key words: crystal structure, hydride ligands, imine ligands, triphenylphosphine ligands,
imine hydrolysis, iridium complexes, orthometallation.
Complexes of the type [M(cod)(PPh3)2]PF6,1,2 (cod
is cyclooctaꢀ1,5ꢀdiene) are well known catalyst precurꢀ
sors for the homogeneous H2ꢀhydrogenation of a variꢀ
ety of unsaturated compounds containing the C=C
H2 and Ar when, at least for the Rh systems, the comꢀ
plexes cisꢀ[M(PPh3)2(Solv)2]+ are typically present.9
Imine binding to Rh centers in systems involving cataꢀ
lyzed hydrogenation of imines has been reported earꢀ
lier.11—13 Our new results on the Rh systems are presented
in Ref. 14. This study focuses on the interaction of imines
with the corresponding Irꢀbased species.
5
(M = Rh, Ir),3,4 C=O and C=N moieties (M = Rh).6
The reactivity of these complexes under H2 in coordiꢀ
nating solvents (e.g., MeOH, acetone, MeCN) is well
documented. For both metals, H2 oxidative addition
and diene reduction to cyclooctane affords the
cis,trans,cisꢀ[M(H)2(PPh3)2(Solv)2]PF6 (Solv is a solvent)
complexes.3,7—9 Our interest in mechanistic aspects of the
homogeneous hydrogenation of imines10,11 prompted inꢀ
vestigations of these species as catalytic precursors because
they are effective at room temperature and 1 atm H2,6
where spectroscopic studies (especially NMR) are renꢀ
dered facile.
Results and Discussion
The stoichiometric reaction between PhCH2N=CHPh
and cis,trans,cisꢀ[Ir(H)2(PPh3)2(Me2CO)2]PF6 (1),8
which is formed in situ from [Ir(cod)(PPh3)2]PF6 (2) and
H2 in acetone, occurs under Ar in acetone at ∼20 °C
(when complex 1 persists in solution) to produce the
orthometallated complex [Ir(H){PhCH2N=CH(oꢀ
C6H4)}(PPh3)2(Me2CO)]PF6 (3) (Scheme 1).
In this complex, the benzylidenearyl group of the
imine, σꢀbound through the Nꢀatom, has undergone oxiꢀ
dative addition of an orthoꢀCH group. The reaction of
complex 1 with excess imine similarly produces comꢀ
pound 3. The structure of complex 3 is shown in Fig. 1,
and the selected structural parameters are given in Table 1.
The PPh3 ligands are mutually trans, and the acetone
ligand is trans to the metallated orthoꢀC atom within the
distorted octahedral structure. The somewhat longer Ir—O
and C(15)—O distances, noted previously for other
The more forcing reaction conditions generally reꢀ
quired for H2ꢀhydrogenation of imines results, at least in
part, from the smaller enthalpic gain associated with
H2ꢀsaturation of the C=X moieties when X = N or O
(∼–60 kJ mol–1
)
relative to the C=C group
(∼–130 kJ mol–1).10 We thus initiated studies of the coorꢀ
dination of imines to the dihydrido complexes at stoichioꢀ
metric and catalytic substrate/catalyst ratios both under
* Materials were presented at the Mark Vol´pin Memorial Inꢀ
ternational Symposium "Modern Trends in Organometallic and
Catalytic Chemistry" dedicated to his 80th anniversary.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2570—2576, December, 2003.
1066ꢀ5285/03/5212ꢀ2715 $25.00 © 2003 Plenum Publishing Corporation

2716
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003
Marcazzan et al.
also been discussed previously.15 A comparison of the
N(1)—C(7) and N(1)—C(8) bond lengths for the imine
ligand shows that the former corresponds to the C=N
bond; this observed endocyclic orthometallation (vs. a
possible exocyclic orthometallation when the C=N group
is outside of the ring) is expected for this imine in its
thermodynamically favoured Eꢀisomeric form.17 (Further
comments on the Xꢀray structure will be discussed beꢀ
low).
Scheme 1
The IR data for complex 3 are consistent with the
literature data for the related IrCl(H){MeN=CH(oꢀ
C6H4)}(PPh3)2 complex formed by displacement of N2
from transꢀIrCl(N2)(PPh3)2 by the reaction with
MeN=CHPh.18 The ν(IrH) band is seen at 2211 cm–1
,
while the cyclometallated C=N moiety gives rise to a
band at 1607 cm–1 compared to that of the free imine
(1644 cm–1), and is consistent with η1ꢀbinding through
the N atom lone pair.18,19 The ν(CO) band for the coordiꢀ
nated acetone is seen at 1651 cm–1 (vs. 1715 cm–1 for free
acetone), being consistent with the literature data.7
The 31P{1H} NMR spectrum of complex 3 in acꢀ
1
etoneꢀd6 shows a singlet at δ 17.05. The H NMR specꢀ
trum contains the expected triplet at δ –16.35 (2JH,P
=
17 Hz) for the hydride, a shift that is downfield of the
2
hydride signals of 1 (δ –27.70, JH,P = 16 Hz),8,14
IrIIIꢀacetone complexes,15,16 reflect the strong transꢀinꢀ
fluence of the orthoꢀC ligand. The large Ir—C(1)—C(15)
angle of 134.6° suggests that the acetone Me groups may
be subjected to steric repulsions by the Ir(PPh3)2 moiety,
and the P(1)—Ir—P(2) angle of 169.2° also indicates that
the phosphine ligands are bent away slightly from the
acetone ligand toward each other; such a behaviour has
which is consistent with the small transꢀinfluence of
the Nꢀatom in complex 3.20 The upfieldꢀshifted resoꢀ
nances for the aromatic protons of the orthometallated
ring were assigned by the 1Hꢀ1H COSY NMR data and on
the basis of the respective multiplicities and integration
data.14 The CH=N signal is also shifted upfield (δ 7.67 vs.
8.50 for the free imine), which is again consistent with
η1ꢀNꢀbinding.18,21
Table 1. Selected bond lengths (d) and angles (ω) for complex 3
More generally, orthometallated compounds have exꢀ
tensively been reviewed, and those containing Nꢀdonor
ligands form complexes that almost exclusively have a
fiveꢀmembered ring structure.21 The mechanistic pathꢀ
way invokes the usual insertion reaction, typical of a nuꢀ
cleophilic metal center with coordinated, relatively basic
phosphines.18 In the formation of complex 3 from 1 (see
Scheme 1), the imine presumably displaces initially a solꢀ
vent ligand, bringing an ortho CH group close to the
metal,18 this being accompanied by reductive elimination
of the hydrido ligands as H2, which was detected in soluꢀ
tion at δH 4.35. The CH oxidative addition, likely proꢀ
moted by the electron density of the Nꢀdonor,18 then
yields complex 3. Similarly to the earlier Ir work,18
our study in acetoneꢀd6 ruled out solvent as the hyꢀ
dride source. Of interest, the reaction of MeN=CHPh
with [RhCl(CO)2]2, containing the more electronꢀwithꢀ
drawing CO ligands, produces the η1ꢀNꢀimine complex
cisꢀRhCl(CO)2(MeN=CHPh) rather than an orthoꢀ
metallated derivative.18 It should be noted that our group
has reported recently on related orthoꢀmetallation of
semicarbazones (substituted imines) at the Rh centers.22
Bond
d/Å
Angle
ω/deg
Ir(1)—P(1)
Ir(1)—P(2)
Ir(1)—O(1)
Ir(1)—N(1)
Ir(1)—C(1)
Ir(1)—H(1)
N(1)—C(7)
N(1)—C(8)
C(1)—C(2)
C(1)—C(6)
C(6)—C(7)
C(8)—C(9)
C(15)—O(1)
2.3161(8)
2.3390(9)
2.203(2)
2.153(3)
2.013(4)
1.48(3)
1.293(5)
1.471(5)
1.398(5)
1.417(5)
1.439(5)
1.511(5)
1.227(5)
Ir(1)—O(1)—C(15) 134.6(3)
Ir(1)—N(1)—C(7) 112.7(2)
Ir(1)—C(1)—C(2) 129.1(3)
Ir(1)—C(1)—C(6) 113.7(3)
P(1)—Ir(1)—P(2) 169.21(3)
P(1)—Ir(1)—O(1) 93.49(7)
P(1)—Ir(1)—N(1) 93.00(8)
P(1)—Ir(1)—C(1) 88.13(9)
P(1)—Ir(1)—H(1) 85(1)
P(2)—Ir(1)—O(1) 92.68(7)
P(2)—Ir(1)—N(1) 95.61(8)
P(2)—Ir(1)—C(1) 87.04(9)
P(2)—Ir(1)—H(1) 86(1)
O(1)—Ir(1)—H(1) 92(1)
N(1)—Ir(1)—C(1) 79.7(1)
N(1)—Ir(1)—H(1) 176(1)
C(1)—Ir(1)—O(1) 171.7(1)
C(1)—Ir(1)—H(1) 96(1)
C(1)—C(6)—C(7) 115.9(3)
C(7)—N(1)—C(8) 121.0(3)
C(15)—C(16) 1.502(6)

IrIIIꢀCyclometallatedꢀimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003 2717
C(33)
C(45)
C(46)
C(34)
C(35)
C(44)
C(47)
C(32)
C(3)
C(2)
C(43)
C(31)
C(29)
C(30)
H(1)
C(42)
C(17)
C(4)
C(48)
C(50)
C(1)
P(1)
C(28)
C(27)
P(2)
C(24)
C(19)
C(37)
C(15)
Ir(1)
C(48)
C(5)
C(6)
C(33)
C(36)
C(41)
C(38)
C(25)
O(1)
N(1)
C(53)
C(20)
C(51)
C(26)
C(16)
C(7)
C(39)
C(40)
C(23)
C(21)
C(22)
C(52)
C(8)
C(9)
C(14)
C(10)
C(13)
C(12)
Fig. 1. ORTEP diagram for [IrH{PhCH2N=CH(oꢀC6H4)}(PPh3)2(Me2CO)]PF6 (3), with 50% probability ellipsoids.
C(11)
Scheme 2
The corresponding MeOH analog of complex 3 was
formed similarly from a 1 : 1 reaction of complex 1 with
PhCH2N=CHPh in MeOH, but was not isolable. The
in situ species, however, was readily identified by solution
31P{1H} NMR (CD3OD, δP, 18.01 (s)) and 1H NMR:
2
δ
H –16.07 (t, 1 H, Ir(H), JH,P = 16 Hz); 5.02 (s, 2 H,
3
CH2); 6.30 (t, 1 H, pꢀC6H4, JH,H = 6.5 Hz); 6.63
(d, 1 H, oꢀC6H4, 3JH,H = 6.5 Hz); 6.74 (m, 2 H, mꢀC6H4,
3JH,H = 6.5 Hz); 7.10—7.65 (m, 35 H, H arom.); 7.77
(s, 1 H, N=CH). However, when a fourꢀfold exꢀ
cess of imine was added to a MeOH solution of
8
cis,trans,cisꢀ[Ir(H)2(PPh3)2(MeOH)2]PF6
under
Ar, spontaneous precipitation of the orthoꢀ
metallated complex [Ir(H){PhCH2N=CH(oꢀ
C6H4)}(PPh3)2(PhCH2NH2)]PF6 (4) slowly occurred
(Scheme 2).
In place of the acetone ligand in complex 3, comꢀ
plex 4 contains benzylamine that is derived from hydrolyꢀ
sis of the imine (Scheme 2); benzaldehyde, the hydrolysis
coꢀproduct, was detected in the filtrate by GLC and
1H NMR analyses. The source of the H2O has not been
established; it could come from the MeOH, although

2718
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003
Marcazzan et al.
this was dried over Mg turnings in the presence of I2
and distilled from the Mg methoxide formed.23 The imine
is a more likely source, especially as excess imine is
needed in MeOH to generate the mixed orthometallated
imine/amine complex 4. That hydrolysis in acetone is not
seen, even in the presence of excess imine, could be due
to acetone competing successfully with the H2O molꢀ
ecules for the coordination site that is presumably reꢀ
quired for the metalꢀpromoted hydrolysis. The lower coꢀ
ordinating ability of MeOH (vs. acetone)24 could account
for the accessibility of a coordination site for the H2O
molecules. The distorted octahedral structure of comꢀ
plex 4 is shown in Fig. 2, and it is remarkably similar to
the structure of complex 3 after replacement of the coorꢀ
dinated acetone with benzylamine. The bond lengths and
angles (Table 2) are very close to those in complex 3, and
even the Ir—N(2)amine distance is the same as the Ir—O
distance in molecule 3.
The Ir—P, Ir—C, and Ir—N(1)imine bond lengths in
both complexes are close to those reported for the related
IrIII complexes,16,25—27 while the Ir—H distances are inꢀ
termediate between some experimentally determined valꢀ
ues (e.g., 1.43 Å)26 and "experimentally fixed" distances
(e.g., 1.60 Å).16
The IR data for complex 4, like those for complex 3,
reveal the ν(IrH) and ν(C=N) bands, as well as ν(NH)
for the amine at 3301 cm–1 (vs. 3373 cm–1 for free
PhCH2NH2) and, of course, no ν(CO) band. Because of
substitution of the amine ligand in more strongly coordiꢀ
nating solvents (see below), NMR characterization (inꢀ
1
cluding Hꢀ13C HETCOR and 13C APT experiments14)
of isolated complex 4 was accomplished in CD2Cl2. Obꢀ
served are: a 31P{1H} singlet at δP 15.04, the hydride signal
2
at δH –17.63 (t, JH,P = 17 Hz), the nonꢀaromatic, benꢀ
zylideneꢀamine protons at δH 5.05 (s, PhCH2N=C) and
7.30 (s, N=CH), and overlapping signals due to coordiꢀ
C(50)
C(49)
C(51)
C(48)
C(54)
C(55)
C(53)
C(46)
C(45)
C(44)
C(52)
C(3)
C(56)
C(47)
C(40)
C(57)
P(2)
C(43)
C(4)
C(5)
C(2)
C(1)
C(42)
C(41)
H(50)
C(33)
C(6)
C(7)
C(32)
Ir(1)
C(21)
C(11)
N(2)
C(10)
C(9)
N(1)
C(8)
C(15)
C(31)
C(20)
C(28)
C(12)
C(23)
P(1)
C(16)
C(13)
C(30)
C(19)
C(24)
C(29)
C(22)
C(14)
C(34)
C(17)
C(25)
C(18)
C(39)
C(27)
C(26)
C(35)
C(36)
C(38)
C(37)
Fig. 2. ORTEP diagram for [IrH{PhCH2N=CH(oꢀC6H4)}(PPh3)2(PhCH2NH2)]PF6 (4), with 50% probability ellipsoids.

IrIIIꢀCyclometallatedꢀimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003 2719
Table 2. Selected bond lengths (d) and angles (ω) for complex
4•2 CH2Cl2
nation of imines using the corresponding Rh precursor
complexes,14 studies that will be presented elsewhere. The
occurrence of hydrolysis and the formation of a mixed
imine—amine, square planar RhI species, under condiꢀ
tions when an initially observed orthometallation of the
imine is not retained, can play a key role in catalysis. The
metalꢀpromoted hydrolytic cleavage of imines is not new;
for example, we have reported28 on the Ru systems that
generate species with coordinated benzylamine formed
from the same initially coordinated PhCH2N=CHPh
imine.
Complex 3 in the presence of excess imine at 1 atm H2
is an inactive hydrogenation catalyst for imines because
of precipitation of neutral dihydrido species such as
Ir(H)2{PhCH2N=CH(oꢀC6H4)}(PPh3)2.14
Bond
d/Å
Angle
ω/deg
Ir(1)—P(1)
Ir(1)—P(2)
Ir(1)—N(1)
Ir(1)—N(2)
Ir(1)—C(1)
Ir(1)—H(50)
N(1)—C(7)
N(1)—C(8)
N(2)—C(15)
C(1)—C(2)
C(1)—C(6)
C(5)—C(6)
C(6)—C(7)
C(8)—C(9)
2.331(1)
2.323(1)
2.167(3)
2.202(3)
2.041(4)
1.52(4)
1.282(5)
1.480(5)
1.495(5)
1.413(5)
1.409(5)
1.400(5)
1.450(5)
1.505(5)
Ir(1)—N(1)—C(7) 113.6(3)
Ir(1)—N(1)—C(8) 124.9(2)
Ir(1)—C(1)—C(2) 129.9(3)
Ir(1)—C(1)—C(6) 114.1(3)
P(1)—Ir(1)—P(2)
167.41(3)
P(1)—Ir(1)—N(1) 95.8(1)
P(1)—Ir(1)—N(2) 92.2(1)
P(1)—Ir(1)—C(1)
88.9(1)
P(1)—Ir(1)—H(50) 85(2)
P(2)—Ir(1)—N(1) 94.9(1)
P(2)—Ir(1)—N(2) 93.2(1)
P(2)—Ir(1)—C(1)
86.7(1)
P(2)—Ir(1)—H(50) 84(2)
N(1)—Ir(1)—N(2) 96.5(1)
N(1)—Ir(1)—C(1) 78.6(1)
N(1)—Ir(1)—H(50) 175(2)
N(1)—C(7)—C(6) 117.9(4)
N(1)—C(8)—C(9) 117.3(3)
N(2)—Ir(1)—C(1) 175.0(1)
N(2)—Ir(1)—H(50) 88(2)
N(2)—C(15)—C(16) 110.9(4)
C(1)—Ir(1)—H(50) 97(2)
C(1)—C(6)—C(7) 115.8(3)
Experimental
C(15)—C(16) 1.504(6)
All manipulations were performed under Ar using standard
Schlenk and/or dryꢀbox techniques. Solvents were dried acꢀ
cording to standard procedures;23 and deuterated solvents
were also dried and degassed prior to use. The complex
[Ir(cod)(PPh3)2]PF6 (2) was prepared according to a published
method,29 using IrCl3•3H2O purchased from Colonial Metꢀ
als Inc. Nꢀbenzylidenebenzylamine (PhCH2N=CHPh from
Aldrich) was purified by distillation and stored under Ar. H2
(Praxair, Extra Dry) was used as received.
nated amine at δH 2.80 (m, CH2NH2 and CH2NH2). The
NMR spectra were recorded at ∼20 °C on a Bruker AVꢀ300
spectrometer (300 MHz for 1H, 121 MHz for 31P{1H}), with
residual solvent protons (1H) and external standard 85% H3PO4
upfieldꢀshifted resonances for the orthometallated ring
3
and a doublet at δ 5.70 (2 H, JH,H = 7 Hz) are also
(
31P{1H}) being used as references; the oꢀ, mꢀ, and pꢀC6H4
present. Based on the 1Hꢀ13C HETCOR data, the latꢀ
ter resonance is attributed to the orthoꢀprotons of the
coordinated PhCH2NH2 group that each couple to the
neighbouring metaꢀprotons; these orthoꢀprotons are thus
strongly affected by the coordination of the amine, and
πꢀarene interactions with Ph groups of the PPh3 ligands
may be present.
notation used for the orthometallated ring is defined as for the
free imine. GLC analyses were performed on a temperatureꢀ
programmable Hewlett—Packard 5890A instrument fitted with
an HP 17 capillary column and a flame ionization detector, and
using He as carrier gas. IR spectra (KBr pellets) were recorded
on an ATI Mattson Genesis Series FTIR instrument; IR bands
are reported in wavenumbers (cm–1). Microanalyses were perꢀ
formed by P. Borda in the analytical laboratory of this deꢀ
partment.
Dissolution of complex 4 in acetoneꢀd6 generates imꢀ
mediately an 8 : 1 mixture of complexes 4 and 3, as
2
[N,oꢀCꢀ(NꢀBenzilidenebenzylaminato)]hydrido(aceꢀ
tone)bis(triphenylphosphine)iridium(III) hexafluorophosphate,
[Ir(H){PhCH2N=CH(oꢀC6H4)}(PPh3)2(Me2CO)]PF6 (3). A red
solution of complex 2 (0.100 g, 0.103 mmol) in acetone (3 mL)
was stirred under H2 (1 atm) for 1 h at ∼20 °C. To the resulting
pale yellow solution, PhCH2N=CHPh (19.5 µL, 0.103 mmol)
was added under Ar, and the mixture was stirred for 24 h; the
volume was then reduced to ∼1 mL to afford spontaneous preꢀ
cipitation of a cream solid that was collected, washed with Et2O
(3×4 mL), and dried in vacuo. Yield of complex 3 was 0.090 g
(78%). Found (%): C, 57.11; H, 4.46; N, 1.39. C53H49F6IrNOP3.
Calculated (%): C, 57.09; H, 4.43; N, 1.26. IR, ν/cm–1: 2211
(Ir—H); 1651 (C=O); 1607 (C=N); 1580. 1H NMR (acetoneꢀ
evidenced by the NMR data for 4, δP 15.57 (d, JH,P
=
2
15 Hz); δH –17.42 (t, JH,P = 16 Hz), showing that
the benzylamine ligand is partially displaced by acetone.
The upfieldꢀshifted resonances for the orthometallated
ring of each complex and signals due to free (δH 1.28
(s, CH2NH2) and 4.47 (s, CH2NH2)) and coordinated
(δH 2.80—2.92 (m, CH2NH2 and CH2NH2)) benzylamine
were also identified. The upfieldꢀshifted signals of the
orthoꢀprotons of the coordinated PhCH2NH2 were seen
3
at δH 5.72 (d, 2 H, JH,H = 7 Hz). Free imine was not
detected, showing that orthometallation is retained. The
NMR spectra in acetoneꢀd6 are timeꢀdependent, and the
ratio of the two species increasingly favoured complex 3
that became the only species observed after several days.
The very different behaviour of the systems in acetone
and in alcohol is important in the catalytic H2ꢀhydrogeꢀ
2
d6), δ: –16.35 (t, 1 H, IrH, JH,P = 17 Hz); 2.10 (s, 6 H,
3
MeCOMe); 5.22 (s, 2 H, CH2); 6.40 (t, 1 H, pꢀC6H4, JH,H
=
3
6.5 Hz); 6.71 (d, 1 H, oꢀC6H4, JH,H = 6.5 Hz); 6.86 (m, 2 H,
mꢀC6H4, 3JH,H = 6.5 Hz); 7.00—7.60 (m, 35 H, H arom.); 7.67
(s, 1 H, N=CH). 31P{1H} NMR (acetoneꢀd6), δ: 17.05 (s).

2720
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003
Marcazzan et al.
[N,oꢀCꢀ(NꢀBenzilidenebenzylaminato)]hydrido(benzylꢀ
amine)bis(triphenylphosphine)iridium(III) hexafluorophosphate,
[Ir(H){PhCH2N=CH(oꢀC6H4)}(PPh3)2(PhCH2NH2)]PF6 (4).
A red suspension of 2 (0.080 g, 0.082 mmol) in MeOH (3 mL)
was stirred under H2 (1 atm) for 1 h at ∼20 °C. The resulting
pale yellow solution was treated with excess PhCH2N=CHPh
(60.0 µL, 0.330 mmol) under Ar, and the mixture was stirred for
48 h, during which time spontaneous precipitation of a cream
solid occurred. The product was collected, washed with Et2O
(3×4 mL), and dried in vacuo. Yield of complex 4 was 0.050 g
(52%). Found (%): C, 58.89; H, 4.94; N, 2.32. C57H52F6IrN2P3.
Calculated (%): C, 58.80; H, 4.47; N, 2.40. IR, ν/cm–1: 3301
(N—H); 2208 (Ir—H); 1605 (C=N); 1576. 1H NMR (CD2Cl2),
This work was financially supported by the Natural
Sciences and Engineering Research Council of Canada
(NSERC).
References
1. R. R. Schrock and J. A. Osborn, J. Am. Chem. Soc., 1971,
93, 2397.
2. L. M. Haines and E. Singleton, J. Chem. Soc., Dalton Trans.,
1972, 1891.
3. R. R. Schrock and J. A. Osborn, J. Am. Chem. Soc., 1976, 98,
4450, and the references therein.
4. R. H. Crabtree, H. Felkin, and G. E. Morris, J. Organomet.
Chem., 1977, 141, 205.
5. R. R. Schrock and J. A. Osborn, J. Chem. Soc., Chem.
Commun., 1970, 567.
6. (a) A. Levi, G. Modena, and G. Scorrano, J. Chem. Soc.,
Chem. Commun., 1975, 6; (b) C. J. Longley, T. J. Goodwin,
and G. Wilkinson, Polyhedron, 1986, 5, 1625.
7. J. R. Shapley, R. R. Schrock, and J. A. Osborn, J. Am. Chem.
Soc., 1969, 91, 2816.
8. R. H. Crabtree, P. C. Demou, D. Eden, J. M. Mihelcic,
C. A. Parnell, J. M. Quirk, and G. E. Morris, J. Am. Chem.
Soc., 1982, 104, 6994.
2
δ: –17.63 (t, 1 H, IrH, JH,P = 17 Hz); 2.80 (m, 4 H, NH2,
CH2NH2); 5.05 (s, 2 H, CH2N=); 5.70 (d, 2 H, oꢀC6H5,
3JH,H = 7 Hz); 6.55 (t, 1 H, pꢀC6H4, 3JH,H = 6.5 Hz); 6.75—7.50
(m, 41 H, H arom.); 7.30 (s, 1 H, N=CH). 31P{1H} NMR
(CD2Cl2), δ: 15.04 (s).
Xꢀray diffraction analyses. Yellow crystals of complexes 3
and 4 were grown by slow evaporation of a 1 : 1 CH2Cl2—hexanes
solution of the respective complexes. The needleꢀlike crystals
of 3, C53H49F6IrNOP3 (M = 1115.11), are monoclinic, space
group P21/n, a = 11.6903(9), b = 15.498(2), c = 25.7533(7) Å,
β = 96.6599(9)°, V = 4634.6(5) Å3, dcalc = 1.598 g cm–3
4. Yellow plateletꢀlike crystals of 4•2 CH2Cl2,
,
Z
=
9. P. Marcazzan, M. B. Ezhova, B. O. Patrick, and B. R.
James, C. R. Chimie, 2002, 5, J. Osborn issue, 373 .
10. B. R. James, Catalysis Today, 1997, 37, 209.
11. P. Marcazzan, B. O. Patrick, and B. R. James, Organometalꢀ
lics, 2003, 22, 1177.
C59H56Cl4F6IrN2P3 (M = 1334.03), are also monoclinic, space
group P21/n, a = 12.7932(4), b = 20.5806(4), c = 21.3390(7) Å,
β = 92.469(2)°, V = 5613.2(2) Å3, dcalc = 1.576 g cm–3, Z = 4.
The crystallographic data for 3 and 4•2 CH2Cl2 can be obtained
from the Cambridge Crystallographic Data Centre.ꢀ
12. (a) G.ꢀJ. Kang, W. R. Cullen, M. D. Fryzuk, B. R. James,
and J. P. Kutney, J. Chem. Soc., Chem. Commun., 1988,
1466; (b) W. R. Cullen, M. D. Fryzuk, B. R. James, J. P.
Kutney, G.ꢀJ. Kang, G. Herb, I. S. Thorburn, and
R. Spogliarich, J. Mol. Catal., 1990, 62, 243; (c) A. G.
Becalski, W. R. Cullen, M. D. Fryzuk, B. R. James, G. J.
Kang, and S. J. Rettig, Inorg. Chem., 1991, 30, 5002.
13. M. D. Fryzuk and W. E. Piers, Organometallics, 1990, 9, 986.
14. P. Marcazzan, Ph. D. Thesis, The University of British Coꢀ
lumbia, Vancouver, 2002.
15. R. H. Crabtree, G. G. Hlatky, C. P. Parnell, B. E. Segmüller,
and R. J. Uriarte, Inorg. Chem., 1984, 23, 354.
16. K. Gruet, R. H. Crabtree, D. H. Lee, L. LiableꢀSands, and
A. L. Rheingold, Organometallics, 2000, 19, 2228.
17. M. Crespo, M. Martinez, J. Sales, X. Solans, and M. Fontꢀ
Bardía, Organometallics, 1992, 11, 1288.
18. (a) J. F. van Baar, K. Vrieze, and D. J. Stufkens, J. Organomet.
Chem., 1975, 85, 249; (b) J. F. van Baar, K. Vrieze, and D. J.
Stufkens, J. Organomet. Chem., 1975, 97, 461.
19. M. Calligaris and L. Randaccio, in Comprehensive Coordinaꢀ
tion Chemistry, Eds. G. Wilkinson, R. D. Gillard, and J. A.
McCleverty, Pergamon Press, Oxford, 1987, 2, 715.
20. H. D. Kaesz and R. B. Saillant, Chem. Rev., 1972, 72, 231.
21. I. Omae, Chem. Rev., 1979, 79, 287.
The Xꢀray diffraction data were collected at 173 K on a
Rigaku/ADSC CCD area detector with graphite monochromated
MoꢀKα radiation. For complex 3, of the 37530 reflections colꢀ
lected, 10205 were unique (Rint = 0.047), the corresponding
numbers for 4 being 46909 and 12040 (Rint = 0.052); equivalent
reflections were merged. Data were collected and processed usꢀ
ing the d*TREK program,30 and corrected for the Lorentz and
polarization effects. The structures were solved by direct methꢀ
ods31 and expanded using Fourier techniques.32 The nonꢀH atꢀ
oms were refined anisotropically; the H atoms bound to Ir were
refined isotropically, and the rest were included in fixed posiꢀ
tions. For 4, two CH2Cl2 molecules were found in the asymmetꢀ
ric unit. The final cycle of fullꢀmatrix leastꢀsquares refinement
for 3 was based on 9884 observed reflections (I > 0.00σ(I )) and
590 variable parameters, the corresponding numbers for 4 being
11720 and 688. Neutral atom scattering factors were taken from
Cromer and Waber.33 Anomalous dispersion effects were inꢀ
34
cluded in Fcalc
;
the values of ∆f´ and ∆f´´35 and the mass atꢀ
tenuation coefficients36 were those of Creagh and coworkers.
All calculations were performed using teXsan37 crystallographic
software. The final reliability factors for 3 were R1 = 0.027
(based on 7787 reflections with I > 3σ(I )) and wR2 = 0.077
(on F 2, all data), with the corresponding numbers for 4 being
R1 = 0.031 (8723 reflections) and wR2 = 0.087.
22. M. B. Ezhova, B. O. Patrick, B. R. James, M. E. Ford, and
B. F. J. Waller, Izv. Akad. Nauk, Ser. Khim., 2003, 2562
[Russ. Chem. Bull., Int. Ed., 2003, 52, No. 12].
ꢀ
These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Camꢀ
bridge Crystallographic Data Centre, 12, Union Road, Camꢀ
bridge CB2 1EZ, UK; fax: (internat.) +44ꢀ1223/336ꢀ033;
Eꢀmail: deposit@ccdc.cam.ac.uk.
23. D. D. Perrin, W. L. F. Amarego, and D. R. Perrin, Purificaꢀ
tion of Laboratory Chemicals, Pergamon Press, Oxford, 1980.
24. J. E. Huheey, E. A. Keiter, and R. L. Keiter, Inorganic
Chemistry, Harper Collins, New York, 1993, p. 370.

IrIIIꢀCyclometallatedꢀimine complexes
Russ.Chem.Bull., Int.Ed., Vol. 52, No. 12, December, 2003 2721
25. D. Carmona, J. Ferrer, M. Lorenzo, M. Santander, S. Ponz,
F. J. Lahoz, and L. A. Oro, Chem. Commun., 2002, 870.
26. D.ꢀH. Lee, J. Chen, J. W. Faller, and R. H. Crabtree, Chem.
Commun., 2001, 213.
27. S. Grundemann, A. Kovacevic, M. Albrecht, J. W. Faller,
and R. H. Crabtree, Chem. Commun., 2001, 2274.
28. D. E. Fogg and B. R. James, Inorg. Chem., 1995, 34, 2557.
29. R. H. Crabtree and G. E. Morris, J. Organomet. Chem.,
1977, 135, 395.
30. d*TREK: Area Detector Software. Version 4.4, Molecular
Structure Corporation, The Woodlands, TX 77381, USA
1996—1998.
31. A. Altomare, M. C. Burla, G. Cammalli, M. Cascarano,
C. Giacovazzo, A. Guagliardi, A. G. G. Moliterni,
G. Polidori, and A. Spagna, SIR97, J. Appl. Cryst., 1999,
32, 115.
Program System, Technical Report of the Crystallography
Laboratory, University of Nijmegen, The Netherlands, 1994.
33. D. T. Cromer and J. T. Waber, International Tables for XꢀRay
Crystallography, The Kynoch Press, Birmingham, UK, 1974,
4, Table 2.2 A.
34. J. A. Ibers and W. C. Hamilton, Acta Crystallogr., 1964,
17, 781.
35. D. C. Creagh and W. J. McAuley, International Tables for
XꢀRay Crystallography, Ed. A. J. C. Wilson, Kluwer Acaꢀ
demic Publishers, Boston, 1992, C, 219, Table 4.2.6.8.
36. D. C. Creagh and J. H. Hubbell, International Tables for
XꢀRay Crystallography, Ed. A. J. C. Wilson, Kluwer Acaꢀ
demic Publishers, Boston, 1992, C, 200, Table 4.2.4.3.
37. teXsan: Crystal Structure Analysis Package, Molecular Strucꢀ
ture Corporation, The Woodlands, TX 77381, USA,
(1996—1998).
32. P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman,
R. de Gelder, R. Israel, and J. M. M. Smits, The DIRDIFꢀ94
Received July 31, 2003