Synthesis of novel terminal iridium phosphinidene complexes

Article abstract of DOI:10.1021/om020062t

Stable, crystalline iridium-complexed phosphinidenes, Cp*(L)Ir=PR, are readily synthesized by (a) the reaction of Cp*(L)IrCl₂ (2, L = PPh₃) with LiPHMes* and (b) dehydrohalogenation of Cp*(PH₂R)IrCl₂ (5, R = Mes*, Is, Mes) with in situ capturing of transient Cp*Ir?PR (4) with phosphines, phosphites, arsines, isocyanides, and carbon monoxide (L). Cp*Ir?PR eluded direct detection. The X-ray crystal structures are reported for Cp*(PPh₃)Ir=PMes* (3) and Cp*(CO)Ir=PMes* (15). The more congested 3 has an E configuration for its Ir=P bond, whereas 15 is obtained in its Z form. The ³¹P NMR chemical shifts and ²Jpp coupling constants are diagnostic for the E and Z forms. More shielded phosphinidene resonances and larger coupling constants are typical for the E isomers. These iridium-complexed phosphinidenes react with gem-diiodides to form phosphaalkenes, but not with carbonyl groups.

Full text of DOI:10.1021/om020062t

3196
Organometallics 2002, 21, 3196-3202
Syn th esis of Novel Ter m in a l Ir id iu m P h osp h in id en e
Com p lexes
Arjan T. Termaten,† Tom Nijbacker,† Marius Schakel,† Martin Lutz,‡
Anthony L. Spek,‡ and Koop Lammertsma*,†
Department of Organic and Inorganic Chemistry, Faculty of Sciences, Vrije Universiteit,
De Boelelaan 1083, NL-1081 HV, Amsterdam, The Netherlands, and Bijvoet Center for
Biomolecular Research, Department of Crystal and Structural Chemistry, Utrecht University,
Padualaan 8, NL-3584 CH, Utrecht, The Netherlands
Received J anuary 29, 2002
Stable, crystalline iridium-complexed phosphinidenes, Cp*(L)IrdPR, are readily synthe-
sized by (a) the reaction of Cp*(L)IrCl2 (2, L ) PPh3) with LiPHMes* and (b) dehydrohalo-
genation of Cp*(PH2R)IrCl2 (5, R ) Mes*, Is, Mes) with in situ capturing of transient Cp*Irt
PR (4) with phosphines, phosphites, arsines, isocyanides, and carbon monoxide (L). Cp*Irt
PR eluded direct detection. The X-ray crystal structures are reported for Cp*(PPh3)IrdPMes*
(3) and Cp*(CO)IrdPMes* (15). The more congested 3 has an E configuration for its IrdP
2
bond, whereas 15 is obtained in its Z form. The 31P NMR chemical shifts and J PP coupling
constants are diagnostic for the E and Z forms. More shielded phosphinidene resonances
and larger coupling constants are typical for the E isomers. These iridium-complexed
phosphinidenes react with gem-diiodides to form phosphaalkenes, but not with carbonyl
groups.
In tr od u ction
The reactivity of stable, isolated representatives of
either Schrock- or Fischer-type phosphinidene com-
plexes has hardly been explored, which is in sharp con-
trast with the wealth of novel (strained) organophos-
phorus compounds that could be synthesized from
transient electrophilic species.2-4 The most investigated
species, zirconocene complex Cp2(PMe3)ZrdPMes*,12
reacts, for example, like tantalum complex [N3N]TadPR
(N3N ) (Me3SiNCH2CH2)3N),8 in a phospha-Wittig man-
ner with aldehydes and ketones to give phosphaalkenes.
In our search to expand the availability of phosphin-
idenes, we were attracted to the late transition metals
of group 9 (Co, Rh, Ir) to generate their yet unknown
Cp(L)MdPR complexes. An extensive computational
survey13 suggests these to be less nucleophilic than the
known metallocene-type complexes Cp2(PMe3)ZrdPMes*,
Cp2ModPMes*, and Cp2WdPMes* when the stabilizing
donor ligand L is a phosphine or CO. In the present
study we focus on the transition metal iridium. Berg-
man et al.14 reported earlier on the related, stable
terminal imido complex Cp*IrtNR. The carbene ana-
logue Cp*(PMe3)IrdCH2 with an extra phosphine ligand
is stable below -40 °C,15 whereas the oxo-complex is
stable as a dimer [Cp*IrO]2.16 We will show convenient
synthetic routes to Cp*(L)IrdPR, report X-ray crystal
Phosphinidenes stabilized by transition metal com-
plexes, LnMdPR, are attracting increased attention.
These low-valent organophosphorus species are isolobal
with the well-known carbene and imido complexes.1
Likewise, they can be categorized into electrophilic or
Fischer-type reagents, such as transient (CO)5MdPR (M
) Cr, Mo, W) and (CO)4FedPN-i-Pr2
2-4
and (stable)
cationic [Cp*(CO)nM ) PN-i-Pr2]+ (n ) 2, M ) Ru; n )
3, M ) Mo, W),5 and into stable nucleophilic or Schrock-
type reagents.2 In 1987 Lappert et al.6 reported the first
such complexes for group 6 transition metals, i.e.,
Cp2MdPR (M ) Mo, W; R ) Mes* (supermesityl; 2,4,6-
tri-tert-butylphenyl), CH(SiMe3)2). Other nucleophilic
complexes have been generated with transition metals
from group 4 (Zr),7 5 (Ta),8,9 and 6 (W)10 and even an
actinide (U).11
* Corresponding author. Tel: + 31-20-444-7474. Fax: + 31-20-444-
7488. E-mail: lammert@chem.vu.nl.
† Vrije Universiteit.
‡ Utrecht University.
(1) (a) Cowley, A. H.; Barron, A. R. Acc. Chem. Res. 1988, 21, 81-
87. (b) Cowley, A. H. Acc. Chem. Res. 1997, 30, 445-451.
(2) Dillon, K. B.; Mathey, F.; Nixon, J . F. Phosphorus: The Carbon
Copy; Wiley: Chichester, 1998; Chapter 3.
(3) Mathey, F. Angew. Chem. 1987, 99, 285-296; Angew. Chem.,
Int. Ed. Engl. 1987, 26, 275-286.
(4) (a) Wit, J . B. M.; van Eijkel, G. T.; de Kanter, F. J . J .; Schakel,
M.; Ehlers, A. W.; Lutz, M.; Spek, A. L.; Lammertsma, K. Angew.
Chem. 1999, 111, 2716-2719; Angew. Chem., Int. Ed. 1999, 38, 2596-
2599. (b) Wit, J . B. M.; van Eijkel, G. T.; Schakel, M.; Lammertsma,
K. Tetrahedron 2000, 56, 137-141.
(9) Bonanno, J . B.; Wolckzanski, P. T.; Lobkovsky, E. B. J . Am.
Chem. Soc. 1994, 116, 11159-11160.
(10) Cowley, A. H.; Pellerin, B. J . Am. Chem. Soc. 1990, 112, 6734-
6735.
(11) Arney, D. S. J .; Schnabel, R. C.; Scott, B. C.; Burns, C. J . J .
Am. Chem. Soc. 1996, 118, 6780-6781.
(5) (a) Sterenberg, B. T.; Carty, A. J . J . Organomet. Chem. 2001,
617-618, 696-701. (b) Sterenberg, B. T.; Udachin, K. A.; Carty, A. J .
Organometallics 2001, 20, 2657-2659.
(12) Breen, T. L.; Stephan, D. W. J . Am. Chem. Soc. 1995, 117,
11914-11921.
(6) Hitchcock, P. B.; Lappert, M. F.; Leung, W. P. J . Chem. Soc.,
Chem. Commun. 1987, 1282-1283.
(13) Ehlers, A. W.; Baerends, E.-J .; Lammertsma, K. J . Am. Chem.
Soc. 2002, 124, 2831-2838.
(7) Hou, Z.; Breen, T. L.; Stephan, D. W. Organometallics 1993, 12,
3158-3167.
(14) Glueck, D. S.; Wu, J .; Hollander, F. J .; Bergman, R. G. J . Am.
Chem. Soc. 1991, 113, 2041-2054.
(8) Cummins, C. C.; Schrock, R. R.; Davis, W. M. Angew. Chem.
1993, 105, 758-761.
(15) Klein, D. P.; Bergman, R. G. J . Am. Chem. Soc. 1989, 111,
3079-3080.
10.1021/om020062t CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/25/2002

Terminal Iridium Phosphinidene Complexes
Organometallics, Vol. 21, No. 15, 2002 3197
Sch em e 1
B. Deh ydr oh alogen ation -Ligan d Addition Rou te.
Whereas Cp*IrtPR (4) eludes direct detection, it may
serve as a synthon for generating phosphinidene com-
plexes. Therefore, we decided to probe its access by
dehydrohalogenation of novel primary phosphine com-
plexes Cp*Ir(PH2R)Cl2 (5) and immediately capturing
transient 4 with a stabilizing transition metal ligand.
This method proved to be both successful and general,
because of the diversity of ligands that can be used. We
investigated the reaction for the ligands PMe3, PPh3,
PH2Mes*, P(OMe)3, dppe, AsPh3, t-BuNC, XyNC, and
CO, all of which give yields of the complexed phosphin-
idene (3, 6-15) of 80% or more (Table 2).
structures for two of them, and demonstrate their
nucleophilic character.
Resu lts a n d Discu ssion
Iridium-complexed phosphinidenes can be formed
from Cp*(L)IrCl2 (2, L ) PPh3) by reaction with lithium
phosphides and in a more versatile manner by dehy-
drohalogenation with simultaneous ligand addition.
A. Lith iu m P h osp h id e Rou te. Complex 2 is readily
prepared from the [Cp*IrCl2]2 dimer (1) and triphen-
ylphosphine in THF.17 Subsequent addition at room
temperature of 2 equiv of LiPHMes*‚3THF in toluene
results in formation of phosphinidene complex 3,
Mes*PH2 (liberated during reaction), and other organo-
phosphorus products, among which is diphosphine
Mes*PH-PHMes* (Scheme 1). The presence of 3 is
evident from its 31P NMR chemical shifts at δ 687 and
Dehydrohalogenation of 5a , formed from [Cp*IrCl2]2
and primary phosphine PH2Mes*, with 1,8-diazabicyclo-
[5.4.0]undec-7-ene (DBU) in the presence of PPh3 gives
phosphinidene 3 in 86% isolated yield (entry 1), thereby
demonstrating the superiority of this method over that
of the lithium phosphide route. Using the smaller isityl
(Is; 2,4,6-tri-isopropylphenyl) and mesityl (Mes) groups
in complexes 5b and 5c, respectively, results likewise
in the corresponding phosphinidene complexes 6 (entry
2) and 7 (entry 3). These have characteristic low-field
31P NMR chemical shifts for their phosphinidene phos-
phorus atom similar to 3 albeit that they are slightly
more shielded, i.e., δ 664 for 6 and δ 652 for 7 vs δ 687
2
25, and the large J PP coupling constant between the
2
31P nuclei of 102 Hz; the low-field resonance is charac-
teristic for a bent terminal phosphinidene complex.1b
Phosphinidene complex 3 was isolated in 43% yield as
stable, mildly air-sensitive, dark green crystals.
The crystal structure of 3 confirms it to be a mono-
meric, terminal phosphinidene complex in which the
large groups around the IrdP(1) bond are in an anti or
E configuration (Figure 1); selected bond distances and
angles are listed in Table 1. The two-legged piano stool
geometry of 3 has an acute P(1)-Ir(1)-P(2) angle of
86.563(19)° between its two legs. The distortion from
planarity of the phenyl ring of the supermesityl group
may result from repulsion between the bulky Cp* and
ortho tert-butyl groups.
for 3. The large J PP coupling constants of 6 (77 Hz) and
7 (75 Hz) suggest these structures to have an E
configuration like that of the more congested 3 (102 Hz).
However, executing the reaction with the unsubstituted
phenyl group, i.e., Cp*Ir(PH2Ph)Cl2,19 results only in
unidentifiable products. Evidently, the size of the phos-
phinidene substituent is important. Throughout the rest
of the study we used the Mes* group as the substituent
at phosphorus, i.e., 5a .
Reaction of 5a with DBU in the absence of a phos-
phine results mostly in unidentifiable products, thereby
illustrating that Cp*IrtPMes* (4a ) itself is unstable
under the reaction conditions.20
We next explored the use of smaller phosphine
ligands. Dehydrohalogenating 5a with DBU in the
presence of primary phosphine PH2Mes* results in
phosphinidene complex 8 in 85% yield (entry 4). Char-
acteristic are the low-field 31P NMR resonance at δ 715
(2J PP ) 20 Hz) for its phosphinidene group and the high-
field resonance for the primary phosphine ligand at δ
) -84 (1J PH ) 384 Hz), which resembles that of 5a (δ
The 2.2121(5) Å Ir(1)-P(1) bond distance is short
compared to the 2.324 Å for the Ir-PPh3 bond of 218
and indicates double-bond character in accordance with
a recent theoretical survey on phosphinidene com-
plexes.13 The IrdP nature is further supported by the
Ir(1)-P(1)-C(1) angle of 113.73(7)°, which is typical for
a bent phosphinidene complex.6,7 Interestingly, the
2.2483(5) Å Ir(1)-P(2) distance for the Ir-PPh3 bond
of 3 is only marginally longer than the Ir(1)-P(1)
phosphinidene bond and shows the triphenylphosphine
group to have a much stronger stabilizing effect than it
has in 2.
Attempts to synthesize Cp*IrtPR (4), free of the
stabilizing PPh3 ligand, in analogy with the reported
imido complex,14 were unsuccessful. Reaction of [Cp*Ir-
Cl2]2 (1) with lithium phosphide LiPHR‚nTHF (R )
Mes*, Mes) led to a mixture of unidentifiable products.
Apparently, Cp*IrtPR is significantly less stable than
its imido analogue.
1
2
-57.1, J PH ) 397 Hz). Because the J PP coupling
constant is 82 Hz smaller than that of 3, and since the
PH2Mes* ligand is far less bulky than PPh3 (especially
when the Mes* group is rotated away), we presume 8
to have the less congested Z or syn configuration.
Evidently, the preference for an E or Z orientation of
(19) Esteban, M.; Pequerul, A.; Carmona, D.; Lahoz, F. J .; Mart´ın,
A.; Oro, L. A. J . Organomet. Chem. 1991, 402, 421-434.
(20) The first dehydrohalogenation to Cp*(Cl)IrdPHMes* using 1
equiv of DBU was confirmed at temperatures below 0 °C by the
presence of resonances at δ 117 (1J PH ) 404 Hz) and 128 (1J PH ) 363
Hz) in a ratio of 85:15 in the 31P NMR spectrum of the complex reaction
mixture. Ligand addition to this phosphide complex with subsequent
dehydrohalogenation of Cp*(L)(Cl)IrdPHMes* will also render phos-
phinidene complexes, as suggested by a referee. This alternative route
cannot be excluded and may, in fact, compete with the didehydroha-
logenation-ligation sequence. Because in the presence of PPh3 31P
NMR resonances are also observed below 0 °C at δ 480-630, we
conclude that free and/or solvent-complexed Cp*IrdPMes* is a major
reactive intermediate in the reaction mixture.
(16) McGhee, W. D.; Foo, T.; Hollander, F. J .; Bergman, R. G. J .
Am. Chem. Soc. 1988, 110, 8543-8545.
(17) Kang, J . W.; Mosely, K.; Maitlis, P. M. J . Am. Chem. Soc. 1969,
91, 5970-5977.
(18) Le Bras, J .; Amouri, H.; Vaissermann, J . J . Organomet. Chem.
1997, 548, 305-307.

3198 Organometallics, Vol. 21, No. 15, 2002
Termaten et al.
F igu r e 1. Displacement ellipsoid plot (50% probability level) of 3. Hydrogen atoms are omitted for clarity.
Ta ble 1. Selected Bon d Dista n ces (Å), An gles
(d eg), a n d Tor sion An gles (d eg) for
Cp *(P P h 3)Ir dP Mes* (3)
mixture of the mononuclear Cp*(dppe)IrdPMes* com-
plex and dinuclear 11 in a ratio of 3:2. Expectedly, the
mononuclear product also has an E configuration, on
the basis of its 31P NMR chemical shift at δ 655.9 and
2J PP value of 83 Hz. We were unable to isolate the
mononuclear product from the reaction mixture, even
when a larger access of dppe was used.
Ir(1)-P(1)
Ir(1)-P(2)
2.2121(5)
2.2483(5)
Ir(1)-P(1)-C(1)
113.73(7)
143.05(4)
86.563(19)
130.39(4)
14.8(3)
P(1)-Ir(1)-Cp(cg)
Ir(1)-Cp(cg) 1.9227(12) P(1)-Ir(1)-P(2)
P(1)-C(1)
P(2)-C(29)
P(2)-C(35)
P(2)-C(41)
1.858(2)
1.839(2)
1.833(2)
1.842(2)
P(2)-Ir(1)-Cp(cg)
C(6)-C(1)-C(2)-C(3)
C(2)-C(1)-C(6)-C(5) -14.1(3)
Non-phosphorus-containing ligands were probed next.
Using triphenylarsine, the heavier congener of PPh3,
results in 12 (93%, entry 8), which we assume to have
an E configuration on the basis of its 31P NMR chemical
shift at δ 655, which is similar to that of 3. Stable
products are also obtained with isocyanide ligands. The
tert-butyl derivative gives phosphinidene complex 13
(91%, entry 9), which we speculate to have a Z config-
uration on the basis of its low-field 31P NMR chemical
shift at δ 740. Likewise, the xylyl derivative gives
phosphinidene 14, which has a similar 31P NMR chemi-
cal shift at δ 757 (93%, entry 10).
Finally, a CO ligand was introduced by leading
gaseous carbon monoxide though the dehydrohalogen-
ating reaction mixture of 5a to give deep red colored
phosphinidene 15 (88%, entry 11). The complex has a
strong IR absorption at 1968 cm-1, which is typical for
a terminal CO ligand. Its very deshielded 31P NMR
chemical shift at δ 805 suggests a Z configuration, which
was confirmed by a single-crystal X-ray structure de-
termination (Figure 2, Table 3). The structure has a
crystallographic mirror plane through C(15), C(12),
Ir(1), C(18), O(1), P(1), C(1), C(4), C(9), and C(11). The
P(1)-Ir(1)-C(18) angle of 94.29(13)° between the two
legs of the piano stool is wider than in 3 and is
attributed to the close proximity of the Mes* substituent
to the CO ligand. The Ir-P(1)-C(1) angle of 113.77(10)°
is remarkably similar to that of 3 and may reflect the
effect of the bulky Mes* group. The Ir(1)-P(1) distance
of 2.1783(8) Å is significantly shorter than in 3, which
may have its origin in their different configurations (E
for 3 and Z for 15) and/or in the different ligand
stabilization (PPh3 for 3 and CO for 15). Phosphinidene
the phosphinidene complex is rather sensitive to the
steric size of the ligand, with larger ones enforcing the
formation of the E form. This is further illustrated in
the next two examples.
Introduction of PMe3, which is also smaller than PPh3,
results in the formation of two isomers of 9 in 85% yield
(entry 5). We assign the E configuration to the major
isomer (92%) on the basis of its phosphinidene reso-
2
nance at δ 629 and the large J PP coupling constant of
84 Hz. The minor Z isomer has a much more deshielded
31P chemical shift for the phosphinidene at δ 727 and a
2
much smaller J PP coupling constant of 18 Hz, both
resembling those of 8.
Two isomers (10) are also formed with trimethyl
phosphite (P(OMe)3; entry 6). In this case the major
isomer (96%) has instead the Z configuration, which we
base on its very low-field 31P NMR chemical shift at δ
797 and small 2J PP coupling constant of 9 Hz; the minor
E isomer, with an 31P NMR chemical shift at δ 680, also
2
has a rather small J PP of 20 Hz.
Performing the dehydrohalogenation of 5a in the
presence of 0.5 equiv of 1,2-bis(diphenylphosphino)-
ethane (dppe), an established dichelating ligand, affords
dinuclear phosphinidene complex 11, (Cp*IrdPMes*)2-
(dppe), in a surprisingly good yield of 82% (entry 7).
Both phosphine groups of dppe serve as a stabilizing
ligand but to different iridium atoms. The single low-
2
field 31P NMR chemical shift at δ 655 and J PP coupling
constant of 69 Hz suggest that both phosphinidene units
have an E configuration for their IrdP bonds. Perform-
ing the reaction with 1.2 equiv of dppe results in a

Terminal Iridium Phosphinidene Complexes
Organometallics, Vol. 21, No. 15, 2002 3199
Ta ble 2. Ir id iu m P h osp h in id en e Com p lexesa
entry
R
L
product
yield (%)
δ
31P (ppm)b
2J PP (Hz)
1
2
3
4
5
Mes*
Is
Mes
Mes*
Mes*
PPh3
PPh3
PPh3
PH2Mes*
PMe3
Cp*(PPh3)IrdPMes* (3)
Cp*(PPh3)IrdPIs (6)
Cp*(PPh3)IrdPMes (7)
Cp*(PH2Mes*)IrdPMes* (8)
Cp*(PMe3)IrdPMes* (9)
86
80
83
85
85
687
664
652
715
629 (92%)
727 (8%)
680 (4%)
797 (96%)
655
655
740
757
805
102
77
75
20
84
18
20
9
6
Mes*
P(OMe)3
Cp*(P(OMe)3)IrdPMes* (10)
94
7
8
9
10
11
Mes*
Mes*
Mes*
Mes*
Mes*
dppe
(Cp*IrdPMes*)2(dppe) (11)
Cp*(AsPh3)IrdPMes* (12)
Cp*(t-BuNC)IrdPMes* (13)
Cp*(XyNC)IrdPMes* (14)
Cp*(CO)IrdPMes* (15)
82
93
91
93
88
69
AsPh3
t-BuNC
XyNC
CO
a
Cp* ) 1,2,3,4,5-pentamethylcyclopentadienyl; Ph ) phenyl; Me ) methyl; Xy ) 2,6-dimethylphenyl; Mes ) 2,4,6-trimethylphenyl; Is
b
) 2,4,6-tri-isopropylphenyl; Mes* ) 2,4,6-tri-tert-butylphenyl; dppe ) 1,2-bis(diphenylphosphino)ethane. In C6D6 as solvent.
Sch em e 2
Sch em e 3
F igu r e 2. Displacement ellipsoid plot (50% probability
level) of 15. Hydrogen atoms are omitted for clarity
(symmetry operation: x, 0.5 - y, z).
dium-complexed phosphinidenes.13 The lower oxophi-
licity of iridium than either the zirconium or tantalum
transition metal complexes may also be a contributing
factor.21
Ta ble 3. Selected Bon d Dista n ces (Å), An gles
(d eg), a n d Tor sion An gles (d eg) for
Cp *(CO)Ir dP Mes* (15)
Ir(1)-P(1)
2.1783(8)
Ir(1)-P(1)-C(1)
113.77(10)
179.2(4)
128.65(4)
94.29(13)
137.07(13)
Phosphinidenes 3 and 15 are sensitive toward acids.
Addition of HCl results in the rapid formation of Cp*Ir-
(L)Cl2 and Mes*PH2. In contrast to Cp2(PMe3)Zrd
PMes*, neither reacts with simple gem-dichlorides, such
as CH2Cl2 and CHCl3, but transfer of the phosphinidene
unit does occur with gem-diiodides. Thus, 3 reacts slowly
at 60 °C with CH2I2 to give the known phosphaalkene
1622 and Cp*Ir(PPh3)I2 (the diiodo analogue of 3),
whereas the same reaction using 15 occurs already at
room temperature. Both phosphinidene complexes react
cleanly with CHI3 to give a 3:1 mixture of the Z and E
isomers of the known phosphaalkene 17,23 again with
the reaction using 15 being the fastest. We speculate
that this difference in behavior between 3 and 15 may
be of a steric nature (E vs Z and PPh3 vs CO), although
Ir(1)-Cp(cg) 1.9132(10) Ir(1)-C(18)-O(1)
Ir(1)-C(18)
P(1)-C(1)
C(18)-O(1)
1.849(3)
1.849(3)
1.142(4)
P(1)-Ir(1)-Cp(cg)
P(1)-Ir(1)-C(18)
C(18)-Ir(1)-Cp(cg)
C(2a)-C(1)-C(2)-C(3) -10.2(4)
15 is the first Schrock-type complex to have a Cp* and
CO ligand at the transition metal.
C. Rea ctivities. Small-scale experiments were per-
formed for 3 and 15 to explore their reactivity (Scheme
3). No reactions were observed with carbonyl compounds
such as benzaldehyde and acetone, neither at ambient
nor at elevated temperatures. This behavior contrasts
that of the “phospha-Wittig” reactivity of Cp2(PMe3)-
ZrdPMes* and (N3N)TadPR that enables the conver-
sion of carbonyl compounds into phosphaalkenes.8,12
However, the results are in line with a recent theoretical
study that predicts a decreased nucleophilicity for iri-
(21) Nugent, W. A.; Mayer, J . M. Metal-Ligand Multiple Bonds;
Wiley: New York, 1989.

3200 Organometallics, Vol. 21, No. 15, 2002
Termaten et al.
added slowly to an orange suspension of 2 (0.66 g, 1.0 mmol)
in toluene (10 mL) and stirred overnight. After removal of the
solvent the brown-green residue was extracted into n-pentane
(50 mL) and filtered to remove LiCl. After removal of the
solvent, the residue was washed with cold n-pentane (10 mL)
to remove Mes*PH2 and crystallized from toluene/n-pentane
at -20 °C to give large green-black crystals of 3 (376 mg, 0.43
mmol, 43%). Mp: 222-224 °C. 31P NMR (C6D6): δ 686.6 (d,
differences in electronic character (charge on P and
strength of the IrdP bond) may contribute. These
aspects are a topic of future study.
Con clu sion s
In this paper, two synthetic routes toward novel
iridium phosphinidene complexes are described. One
uses the reaction of Cp*(L)IrCl2 (2) with LiPHMes*,
which we investigated for L ) PPh3. The other more
versatile, high-yielding, and thereby superior method
employs dehydrohalogenation of Cp*(PH2R)IrCl2 (5)
with in situ capturing of transient Cp*IrtPR (4) with
stabilizing ligands, such as phosphines, phosphites,
arsines, isocyanides, and carbon monoxide. Attempts to
detect Cp*IrtPR (4) were unsuccessful. The X-ray
crystal structures for Cp*(PPh3)IrdPMes* (3) and Cp*-
(CO)IrdPMes* (15) showed the IrdP bond of these
phosphinidene complexes to have E and Z configura-
tions, respectively. The 31P NMR chemical shifts of the
phosphinidene phosphorus of 3 and 6-15, and where
2
2J PP ) 102 Hz, IrdP), 24.8 (d, J PP ) 102 Hz, Ir-PPh3). 1H
4
NMR (C6D6): δ 1.34 (d, J PC ) 1.30 Hz, 15H, C5(CH3)5, 1.51
(s, 9H, p-C(CH3)3), 1.61 (s, 18H, o-C(CH3)3), 7.07-7.19 (m, 9H,
PPh3), 7.48 (s, 2H, m-Mes*), 7.92 (m, 6H, PPh3). 13C{1H} NMR
(C6D6): δ 9.75 (s, C5(CH3)5), 32.2 (s, o-C(CH3)3), 32.3 (s,
p-C(CH3)3), 34.6 (s, p-C(CH3)3), 38.5 (s, o-C(CH3)3), 94.0 (d, 2J PC
3
) 3.7 Hz, C5(CH3)5), 120.5 (s, m-Mes*), 127.1 (d, J PC ) 10.0
Hz, m-PPh3), 129.2 (d, 4J PC ) 2.2 Hz, p-PPh3), 135.6 (d, 2J PC
)
1
10.5 Hz, o-PPh3), 136.8 (d, J PC ) 52.7 Hz, i-PPh3), 145.3 (s,
1
3
o-Mes*), 145.9 (s, p-Mes*), 168.6 (dd, J PC ) 106 Hz, J PC
)
21.1, i-Mes*). HRMS: calcd for C46H59P2Ir 866.37207; found
866.37055.
[Cp *(P H2Mes*)Ir Cl2] (5a ). Mes*PH2 (0.21 g, 0.75 mmol)
was added to a dark orange solution of [Cp*IrCl2]2 (0.25 g, 0.31
mmol) in CH2Cl2 (25 mL), which was stirred for 4 h at 40 °C
and filtered to remove insoluble material. After concentrating
the solution, n-pentane (30 mL) was added slowly to cause
precipitation of an orange crystalline product, which was
isolated by filtration, washed with n-pentane (25 mL), and
dried in vacuo to give 5a (0.33 g, 0.49 mmol, 79%). Mp: 219-
2
applicable the magnitude of the J PP coupling constant,
are diagnostic for the E and Z forms. The Z form is
preferred with smaller ligands and the E form with
bulky ones.
Phosphinidene complexes 3 and 15 are unreactive
toward carbonyl groups. Phosphaalkenes are obtained
in the reaction of 3 and 15 with gem-diiodides, such as
CH2I2 and CHI3, and “re-formation” of PH2Mes* and
Cp*Ir(L)Cl2 occurs on treatment with HCl. The reactiv-
ity of 15 is slightly higher than that of 3.
1
220 °C (dec). 31P NMR (CDCl3): δ -57.1 (t, J PH ) 397 Hz).
4
1H NMR (CDCl3): δ 1.32 (s, 9H, p-C(CH3)3), 1.33 (d, J PH
)
1
1.0 Hz, 15H, C5(CH3)5), 1.55 (s, 18H, o-C(CH3)3), 6.76 (d, J PH
) 397 Hz, 2H, PH2), 7.49 (d, J PH ) 2.8 Hz, 2H, m-Mes*). 13C-
4
{1H} NMR (CDCl3): δ 8.50 (d, J PC ) 0.8 Hz, C5(CH3)5), 31.1
3
4
(s, p-C(CH3)3), 33.0 (d, J PC ) 1.5 Hz, o-C(CH3)3), 34.9 (s,
3
2
p-C(CH3)3), 38.0 (d, J PC ) 2.2 Hz, o-C(CH3)3), 91.8 (d, J PC
)
1
3.3 Hz, C5(CH3)5), 115.7 (d, J PC ) 38.6 Hz, i-Mes*), 122.3 (d,
Exp er im en ta l Section
2
3J PC ) 10.0 Hz, m-Mes*), 152.4 (s, p-Mes*), 155.8 (d, J PC
)
5.2 Hz, o-Mes*). IR (KBr, cm-1): ν(PH) 2421, 2376. HRMS:
calcd for C28H46PCl2Ir 676.23431; found 676.23327. Anal. Calcd
for C28H46PCl2Ir: C, 49.69; H, 6.86; P, 4.58. Found: C, 49.59;
H, 6.68; P, 4.68.
Gen er a l Da ta . All experiments were performed in flame-
dried glassware and under an atmosphere of dry nitrogen or
argon. Solvents were distilled (under N2) from sodium (tolu-
ene), sodium benzophenone (THF), diphosphoruspentoxide
(CH2Cl2, CHCl3), or lithium aluminum hydride (n-pentane,
n-hexane). Deuterated solvents were dried over 4 Å molecular
sieves (CDCl3, C6D6). All solid starting materials were dried
[Cp *(P H2Is)Ir Cl2] (5b). In a fashion similar to that de-
scribed for 5a , IsPH2 (0.18 g, 0.75 mmol) was used to give
orange crystals of 5b (0.34 g, 0.54 mmol, 87%). Mp: 210-212
1
°C (dec). 31P NMR (CDCl3): δ -76.8 (triplet, J PH ) 395 Hz).
1
in vacuo. H, 13C, and 31P NMR spectra were recorded at 300
3
1H NMR (CDCl3): δ 1.25 (d, J HH ) 6.9 Hz, 6H, p-CH(CH3)2),
K on a Bruker Avance 250 spectrometer at 250.13, 62.90, and
101.25 MHz, respectively. 1H NMR spectra were referenced
to CHCl3 (δ 7.27 ppm) or C6D5H (δ 7.17 ppm), 13C NMR spectra
to CDCl3 (δ 77.16 ppm) or C6D6 (δ 128.06 ppm), and 31P NMR
spectra to external 85% H3PO4. IR spectra were recorded on a
Mattson-6030 Galaxy FTIR spectrophotometer, and high-
resolution mass spectra (HRMS) on a Finnigan Mat 900
spectrometer. Elemental analyses were performed by Mik-
roanalytisches Labor Pascher, Remagen-Bandorf, Germany.
[Cp*IrCl2]2,24 Cp*(PPh3)IrCl2,17 IsPH2,25 Mes*PH2,26 and
LiPHMes*‚3THF7 were prepared according to literature pro-
cedures. MesPH2 was prepared, analogously to IsPH2, by
LiAlH4 reduction of MesPCl2.27
3
4
1.30 (d, J HH ) 6.6 Hz, 12H, o-CH(CH3)2), 1.58 (d, J PH ) 2.7
Hz, 15H, C5(CH3)5), 2.90 (sep, 3J HH ) 6.9 Hz, 1H, p-CH(CH3)2),
3.18 (sep, 3J HH ) 6.6 Hz, 2H, o-CH(CH3)2), 5.83 (d, 1J PH ) 395
Hz, 2H, PH2), 7.08 (d, 4J PH ) 3.3 Hz, 2H, m-Is). 13C{1H} NMR
(CDCl3): δ 8.73 (s, C5(CH3)5), 24.0 (s, p-CH(CH3)2), 24.4 (s,
o-CH(CH3)2), 32.2 (d, 3J PC ) 9.5 Hz, o-CH(CH3)2), 34.5 (s, p-CH-
(CH3)2), 92.3 (d, 2J PC ) 3.2 Hz, C5(CH3)5), 114.1 (d, 1J PC ) 52.9
3
4
Hz, i-Is), 121.8 (d, J PC ) 8.3 Hz, m-Is), 152.8 (d, J PC ) 2.4
Hz, p-Is), 153.0 (d, 2J PC ) 7.4 Hz, o-Is). IR (KBr, cm-1): ν(PH)
2400, 2371. HRMS: calcd for C25H40PCl2Ir 634.18738; found
634.18513.
[Cp *(P H2Mes)Ir Cl2] (5c). In a fashion similar to that
described for 5a , MesPH2 (0.10 g, 0.66 mmol) was used to give
orange crystals of 5c (0.25 g, 0.45 mmol, 73%), which retained
a small amount of CH2Cl2 (0.2 equiv). Mp: 228-230 °C (dec).
[Cp *(P P h 3)Ir dP Mes*] (3). A freshly prepared solution of
LiPHMes*‚3THF (1.0 g, 2.0 mmol) in toluene (20 mL) was
1
1
31P NMR (CDCl3): δ -75.1 (triplet, J PH ) 398 Hz). H NMR
(CDCl3): δ 1.55 (d, 4J PH ) 2.6 Hz, 15H, C5(CH3)5), 2.34 (s, 3H,
p-CH3), 2.42 (s, 6H, o-CH3), 5.85 (d, 1J PH ) 397.7 Hz, 2H, PH2),
(22) Appel, R.; Casser, C.; Immenkeppel, M.; Knoch, F. Angew.
Chem. 1984, 96, 905-906; Angew. Chem., Int. Ed. Engl. 1984, 23, 895-
896.
(23) (a) Appel, R.; Immenkeppel, M. Z. Anorg. Allg. Chem. 1987,
553, 7-14. (b) Goede, S.; Bickelhaupt, F. Chem. Ber. 1991, 124, 2677-
2684.
(24) White, C.; Yates, A.; Maitlis, P. M. Inorg. Synth. 1992, 29, 228-
234.
(25) van den Winkel, Y.; Bastiaans, H. M. M.; Bickelhaupt, F. J .
Organomet. Chem. 1991, 405, 183-194.
(26) Cowley, A. H.; Kilduff, J . E.; Newman, T. H.; Pakulski, M. J .
Am. Chem. Soc. 1982, 104, 5820-5821.
6.97 (d, J PH ) 2.7 Hz, 2H, m-Mes). 13C{1H} NMR (CDCl3): δ
4
3
8.53 (s, C5(CH3)5), 21.3 (s, p-CH3), 22.1 (d, J PC ) 8.9 Hz,
o-CH3), 92.3 (d, 2J PC ) 3.3 Hz, C5(CH3)5), 116.6 (d, 1J PC ) 51.3
3
4
Hz, i-Mes), 129.5 (d, J PC ) 8.3 Hz, m-Mes), 141.4 (d, J PC
)
2.5 Hz, p-Mes), 142.1 (d, 2J PC ) 7.7 Hz, o-Mes). IR (KBr, cm-1):
(27) Nief, F.; Mathey, F. Tetrahedron 1991, 47, 6673-6680.

Terminal Iridium Phosphinidene Complexes
Organometallics, Vol. 21, No. 15, 2002 3201
ν(PH) 2396, 2346. Anal. Calcd for C19H28PCl2Ir‚0.2CH2Cl2:
C, 40.64; H, 5.05; P, 5.46. Found: C, 40.30; H, 4.87; P, 5.48.
[Cp *(P P h 3)Ir dP Mes*] (3) fr om 5a . A yellow-orange solu-
tion of 5a (135 mg, 0.20 mmol) in CH2Cl2 (2.5 mL) was added
dropwise to a solution of DBU (59.8 µL, 0.40 mmol) and PPh3
(52.5 mg, 0.20 mmol) in toluene (5 mL) and stirred for an
additional 5 min. After removal of the solvents the residue
was extracted with n-pentane (25 mL), filtered, and concen-
trated to give 3 (149 mg, 0.172 mmol, 86%). The spectroscopic
data are identical to those described above. The same proce-
dure was used to prepare compounds 6-15.
PMe3). 1H NMR (C6D6): δ 1.50 (s, 9H, p-C(CH3)3), 1.56 (s, 15H,
2
C5(CH3)5), 1.61 (d, J PH ) 9.5 Hz, 9H, PMe3), 1.75 (s, 18H,
o-C(CH3)3), 7.48 (s, 2H, m-Mes*). 13C{1H} NMR (C6D6): δ 10.5
1
3
(s, C5(CH3)5), 20.6 (dd, J PC ) 38.1 Hz, J PC ) 13.5 Hz, PMe3),
4
32.2 (s, p-C(CH3)3), 32.5 (d, J PC ) 8.9 Hz, o-C(CH3)3), 34.7 (s,
2
p-C(CH3)3), 38.7 (s, o-C(CH3)3), 93.0 (d, J PC ) 3.7 Hz, C5-
(CH3)5), 120.4 (s, m-Mes*), 145.6 (s, p-Mes*), 145.7 (s, o-Mes*),
1
3
169.6 (dd, J PC ) 108.4 Hz, J PC ) 19.2 Hz, i-Mes*). HRMS:
calcd for C31H53P2Ir 680.32513; found 680.32644. Minor isomer
(8%) (Z)-9. 31P NMR (C6D6): 726.6 (d, J PP ) 17.6 Hz, IrdP),
2
2
1
-41.7 (d, J PP ) 17.6 Hz, Ir-PMe3). H NMR (C6D6): δ 0.95
(d, J PH ) 9.4 Hz, 9H, PMe3), 1.46 (s, 9H, p-C(CH3)3), 1.64 (s,
2
[Cp *(P P h 3)Ir dP Is] (6). 6 was prepared from 5b (127 mg,
0.20 mmol), DBU (59.8 µL, 0.40 mmol), and PPh3 (52.5 mg,
0.20 mmol) to give dark orange-red crystals (131 mg, 0.159
mmol, 80%). Mp: 140-142 °C. 31P NMR (C6D6): δ 663.8 (d,
2J PP ) 77 Hz, IrdP), 27.3 (d, 2J PP ) 77 Hz, Ir-PPh3). 1H NMR
18H, o-C(CH3)3), 1.99 (bs, 15H, C5(CH3)5), 7.45 (s, 2H, m-Mes*).
[Cp *(P (OMe)3)Ir dP Mes*] (10). 10 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and P(OMe)3
(24 µL, 0.20 mmol) as a mixture of two isomers of 10 (136 mg,
0.187 mmol, 94%) obtained as dark purple-red crystals. Major
3
(CDCl3): δ 1.15 (d, J HH ) 6.7 Hz, 6H, o-CH(CH3)2), 1.42 (d,
2
isomer (96%) (Z)-10. 31P NMR (C6D6): δ 797.0 (d, J PP ) 8.8
4
3J HH ) 6.9 Hz, 6H, p-CH(CH3)2), 1.46 (d, J PH ) 1.1 Hz, 15H,
2
Hz, IrdP), 101.6 (d, J PP ) 8.8 Hz, P(OCH3)3). 1H NMR
3
C5(CH3)5), 1.57 (d, J HH ) 6.8 Hz, 6H, o-CH(CH3)2), 3.02 (sep,
3J HH ) 6.9 Hz, 1H, p-CH(CH3)2), 3.57 (sep, 3J HH ) 6.8 Hz, 2H,
o-CH(CH3)2), 7.00-7.15 (m, 9H, PPh3), 7.13 (s, 2H, m-Is), 7.92-
7.99 (m, 6H, PPh3). 13C{1H} NMR (CDCl3): δ 9.44 (s, C5(CH3)5),
23.2 (s, p-CH(CH3)2), 24.7 (bs, o-CH(CH3)2), 25.0 (s, o-CH-
(CH3)2), 30.1 (bs, o-CH(CH3)2), 34.9 (s, p-CH(CH3)2), 93.6 (d,
(C6D6): δ 1.43 (s, 9H, p-C(CH3)3), 1.61 (s, 18H, o-C(CH3)3), 2.02
(d, 4J PH ) 2.1 Hz, 15H, C5(CH3)5), 3.05 (d, 3J PH ) 11.9 Hz, 9H,
P(OCH3)3), 7.46 (s, 2H, m-Mes*). 13C{1H} NMR (C6D6): δ 10.1
4
(s, C5(CH3)5), 31.9 (s, p-C(CH3)3), 32.6 (d, J PC ) 7.2 Hz,
o-C(CH3)3), 34.8 (s, p-C(CH3)3), 39.1 (s, o-C(CH3)3), 50.9 (d, 2J PC
2
3
2J PC ) 3.8 Hz, C5(CH3)5), 119.6 (s, m-Is), 127.3 (d, J PC ) 10.1
) 4.1 Hz, P(OCH3)3), 96.6 (d, J PC ) 4.8 Hz, C5(CH3)5), 120.9
Hz, m-PPh3), 129.4 (d, 4J PC ) 2.2 Hz, p-PPh3), 135.8 (d, 2J PC
10.7 Hz, o-PPh3), 137.1 (d, J PC ) 52.0 Hz, i-PPh3), 143.6 (s,
o-Is), 146.9 (s, p-Is). HRMS: calcd for C43H53P2Ir 824.32513;
found 824.32622.
)
(s, m-Mes*), 145.0 (s, o-Mes*), 146.4 (s, p-Mes*), 168.9 (dd,
3
1J PC ) 102 Hz, J PC ) 3 Hz, i-Mes*). HRMS: calcd for
1
C
31H53O3P2Ir 728.30988; found 728.30834. Minor isomer (4%)
(E)-10. 31P NMR (C6D6): 680.3 (d, 2J PP ) 20.4 Hz, IrdP), 105.6
2
(d, J PP ) 20.4 Hz, Ir-P(OCH3)3).
[Cp *(P P h 3)Ir dP Mes] (7). 7 was prepared from 5c (110 mg,
0.20 mmol), DBU (59.8 µL, 0.40 mmol), and PPh3 (52.5 mg,
0.20 mmol) to give dark orange-red crystals (123 mg, 0.166
mmol, 83%). Mp: 165-167 °C. 31P NMR (C6D6): δ 651.8 (d,
2J PP ) 75 Hz, IrdP), 27.9 (d, 2J PP ) 75 Hz, Ir-PPh3). 1H NMR
[(Cp *Ir dP Mes*)2d p p e] (11). 11 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and dppe
(39.8 mg, 0.10 mmol) as dark red crystals (132 mg, 0.082 mmol,
2
82%). Mp: >205 °C (dec). 31P NMR (C6D6): δ 654.8 (d, J PP
)
2
1
4
69 Hz, IrdP), 10.1 (d, J PP ) 69 Hz, dppe). H NMR (C6D6): δ
1.26 (s, 30H, C5(CH3)5), 1.53 (s, 18H, p-C(CH3)3), 1.71 (s, 36H,
o-C(CH3)3), 3.31 (bs, 4H, CH2), 7.04-7.10 (m, 4H, p-PPh2),
7.17-7.25 (m, 8H, o-PPh2), 7.52 (s, 2H, m-Mes*), 7.85-7.93
(m, 8H, m-PPh2). 13C{1H} NMR (C6D6): δ 9.63 (s, C5(CH3)5),
(C6D6): δ 1.42 (d, J PH ) 1.46 Hz, 15H, C5(CH3)5), 2.31 (s, 6H,
o-CH3), 2.39 (s, 3H, p-CH3), 6.85 (bs, 2H, m-Mes), 7.03-7.19
(m, 9H, PPh3), 7.89-7.97 (m, 6H, PPh3). 13C{1H} NMR
3
3
(C6D6): δ 9.33 (d, J PC ) 0.5 Hz, C5(CH3)5), 19.9 (d, J PC ) 6.4
2
Hz, o-CH3), 21.2 (s, p-CH3), 93.7 (d, J PC ) 3.7 Hz, C5(CH3)5),
1
3
3
23.7 (dd, J PC ) 31.1 Hz, J PC ) 21.2 Hz, CH2), 32.3 (s,
o-C(CH3)3), 32.5 (s, p-C(CH3)3), 34.7 (s, p-C(CH3)3), 38.7 (s,
o-C(CH3)3), 93.6 (m, C5(CH3)5), 120.6 (s, m-Mes*), 127.8 (s,
127.4 (d, J PC ) 10.1 Hz, m-PPh3), 128.3 (s, m-Mes), 129.5 (d,
4J PC ) 2.2 Hz, p-PPh3), 131.3 (d, J PC ) 3.5 Hz, o-Mes), 134.4
2
2
1
(s, p-Mes), 135.7 (d, J PC ) 10.6 Hz, o-PPh3), 136.4 (d, J PC
)
m-PPh2), 129.5 (s, p-PPh2), 134.4 (m, o-PPh2), 135.9 (d, 1J PC
)
1
3
51.9 Hz, i-PPh3), 164.1 (dd, J PC ) 90.3 Hz, J PC ) 16.9 Hz,
i-Mes). HRMS: calcd for C37H41P2Ir 740.23126; found 740.23122.
[Cp *(P H2Mes*)Ir dP Mes*] (8). 8 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and Mes*PH2
(55.6 mg, 0.20 mmol) as a dark purple powder (150 mg, 0.170
mmol, 85%). The compound could not be recrystallized properly
due to high solubility and therefore contains minor impurities.
48.4 Hz, i-PPh2), 145.2 (s, o-Mes*), 145.8 (s, p-Mes*), 170.1
(dd, J PC ) 105.3 Hz, J PC ) 15.6 Hz, i-Mes*). Anal. Calcd for
82H112P4Ir2: C, 61.32; H, 7.03; P, 7.71. Found: C, 60.23; H,
1
3
C
7.03; P, 7.46. HRMS could not be obtained due to the high
molecular weight of the compound (1606.12). Performing the
reaction with 1.2 equiv of dppe resulted in a 2:3 mixture of 11
and the mononuclear compound, [Cp*(dppe)IrdPMes*]. 31P
2
31P NMR (C6D6): δ 714.7 (d, J PP ) 20 Hz, IrdP), -84.4 (dt,
NMR (C6D6): δ 655.9 (d, 2J PP ) 83 Hz, IrdP), 14.8 (dd, 2J PP
83 Hz, J PP ) 40 Hz, Ir-PPh2-CH2CH2PPh2), -9.0 (d, J PP
40 Hz, Ir-PPh2-CH2CH2PPh2).
)
)
2
1
1J PH ) 384 Hz, J PP ) 20 Hz, Ir-PH2Mes*). H NMR (C6D6):
δ 1.27 (s, 9H, p-C(CH3)3), 1.42 (s, 9H, p-C(CH3)3), 1.48 (s, 18H,
o-C(CH3)3), 1.66 (s, 15H, C5(CH3)5), 1.70 (s, 18H, o-C(CH3)3),
3
3
1
3
[Cp *(AsP h 3)Ir dP Mes*] (12). 12 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and AsPh3
(61.2 mg, 0.20 mmol) as dark orange-red crystals (169 mg,
0.186 mmol, 93%). Mp: 173-174 °C. 31P NMR (C6D6): δ 654.9
6.68 (dd, 2H, J PH ) 384 Hz, J PH ) 8.2 Hz, PH2), 7.45 (d, 2H,
4J PH ) 2.1 Hz, m-Mes*), 7.56 (bs, 2H, m-Mes*). 13C{1H} NMR
(C6D6): δ 9.94 (s, C5(CH3)5), 31.5 (s, p-C(CH3)3), 32.0 (s,
p-C(CH3)3), 32.4 (d, J PC ) 7.0 Hz, o-C(CH3)3), 33.6 (d, J PC
2.7 Hz, o-C(CH3)3), 34.6 (s, p-C(CH3)3), 34.8 (s, p-C(CH3)3), 38.5
4
4
)
1
(s, IrdP). H NMR (C6D6): δ 1.40 (s, 15H, C5(CH3)5), 1.51 (s,
3
2
9H, p-C(CH3)3), 1.66 (s, 18H, o-C(CH3)3), 7.06-7.22 (m, 9H,
AsPh3), 7.47 (s, 2H, m-Mes*), 7.89-7.93 (m, 6H, AsPh3). 13C-
{1H} NMR (C6D6): δ 9.98 (s, C5(CH3)5), 32.2 (s, p-C(CH3)3), 32.4
(d, J PC ) 0.9 Hz, o-C(CH3)3), 39.1 (s, o-C(CH3)3), 94.2 (d, J PC
3
) 3.3 Hz, C5(CH3)5), 120.4 (s, m-Mes*PH2), 122.0 (d, J PC
)
1
8.6 Hz, m-Mes*PdIr), 125.6 (d, J PC ) 36.5 Hz, i-Mes*PH2),
4
4
(d, J PC ) 7.1 Hz, o-C(CH3)3), 34.6 (s, p-C(CH3)3), 38.6 (s,
145.7 (s, o-Mes*), 146.2 (s, o-Mes*), 149.7 (d, J PC ) 2.4 Hz,
p-Mes*), 153.9 (d, 2J PC ) 4.9 Hz, o-Mes*), 169.1 (d, 1J PC ) 99.2
Hz, i-Mes*PdIr). HRMS: calcd for C46H75P2Ir 882.49725;
found 882.49653.
o-C(CH3)3), 91.4 (s, C5(CH3)5), 120.4 (s, m-Mes*), 128.1 (s,
m-AsPh3), 129.4 (s, p-AsPh3), 134.9 (s, o-AsPh3), 137.3 (d, 3J PC
) 3.1 Hz, i-AsPh3), 145.9 (s, o-Mes*), 146.0 (s, p-Mes*), 168.9
1
(d, J PC ) 112 Hz, i-Mes*). HRMS: calcd for C46H59AsPIr
[Cp *(P Me3)Ir dP Mes*] (9). 9 was prepared from 5a (135
mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and PMe3 (0.20
mL of a 1.0 M solution in toluene, 0.20 mmol) as a mixture of
two isomers obtained as a dark purple-red powder (116 mg,
0.171 mmol, 85%). Major isomer (92%) (E)-9. 31P NMR (C6D6):
910.31989; found 910.32009.
[Cp *(t-Bu NC)Ir dP Mes*] (13). 13 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and t-BuNC
(23 µL, 0.20 mmol) as large dark pink-red crystals (125 mg,
0.182 mmol, 91%). Mp: 144-146 °C. 31P NMR (C6D6): δ 740.1
2
2
δ 629.3 (d, J PP ) 83.5 Hz, IrdP), -37.3 (d, J PP ) 83.5 Hz,

3202 Organometallics, Vol. 21, No. 15, 2002
Termaten et al.
1
(s, IrdP). H NMR (C6D6): δ 0.94 (s, 9H, CN-C(CH3)3), 1.44
2J PH ) 39.7 Hz, (Z)-17, 73%), 293.1 (d, 2J PH ) 26.4 Hz, (E)-17,
1
(s, 9H, p-C(CH3)3), 1.69 (s, 18H, o-C(CH3)3), 2.09 (s, 15H, C5-
27%). H and 13C NMR are as reported in the literature.23
(CH3)5), 7.52 (s, 2H, m-Mes*). 13C{1H} NMR (C6D6): δ 10.0 (s,
Cr ysta l Str u ctu r e Deter m in a tion of Com p lexes 3 a n d
15. X-ray intensities were measured on a Nonius KappaCCD
diffractometer with rotating anode (λ ) 0.71073 Å). The
structures were solved with automated Patterson methods
(DIRDIF97)28 and refined with SHELXL9729 against F2 of all
reflections. Molecular illustration, structure checking, and
calculations were performed with the PLATON package.30
Cr ysta l Str u ctu r e Deter m in a tion of 3. C46H59IrP2, Mr
) 866.07, black block, 0.27 × 0.20 × 0.11 mm3, temp ) 150(2)
K, triclinic, space group P1h (No. 2), a ) 9.7474(1) Å, b )
14.4034(2) Å, c ) 16.9057(2) Å, R ) 64.8313(5)°, â ) 78.2842(5)°,
γ ) 72.4545(5)°, V ) 2040.49(4) Å3, Z ) 2, F ) 1.410 g/cm3.
Absorption correction based on multiple measured reflections
(PLATON,30 routine MULABS, µ ) 3.38 mm-1, 0.54-0.71
transmission); 51 672 measured reflections up to (sin θ/λ)max
) 0.65 Å-1, of which 9232 were unique (Rint ) 0.0491). R [I >
2σ(I)]: R1 ) 0.0200, wR2 ) 0.0475. R [all reflections]: R1 )
0.0219, wR2 ) 0.0484. S ) 1.061.
Cr ysta l Str u ctu r e Deter m in a tion of 15. C29H44IrOP, Mr
) 631.81, dark red plate, 0.24 × 0.24 × 0.09 mm3, temp )
130(2) K, orthorhombic, space group Pnma (No. 62), a )
18.0642(1) Å, b ) 14.7379(1) Å, c ) 10.5269(1) Å, V ) 2802.56-
(4) Å3, Z ) 4, F ) 1.497 g/cm3. Analytical absorption correction
(PLATON,30 routine ABST, µ ) 4.84 mm-1, 0.32-0.53 trans-
mission); 75 667 measured reflections up to (sin θ/λ)max ) 0.90
Å-1, of which 8861 were unique (Rint ) 0.0490). R [I > 2σ(I)]:
R1 ) 0.0287, wR2 ) 0.0742. R [all reflections]: R1 ) 0.0485,
wR2 ) 0.0815. S ) 0.891.
4
C5(CH3)5), 31.5 (s, C(CH3)3), 32.1 (s, C(CH3)3), 32.1 (d, J PC
)
7.5 Hz, o-C(CH3)3), 34.9 (s, p-C(CH3)3), 39.1 (s, o-C(CH3)3), 55.3
(s, NC(CH3)3), 95.4 (s, C5(CH3)5), 121.5 (s, m-Mes*), 142.9 (bs,
CN), 145.4 (s, p-Mes*), 146.3 (s, o-Mes*), 167.6 (d, 1J PC ) 97.2
Hz, i-Mes*). IR (KBr, cm-1): ν(CN) 2120, 2076. HRMS: calcd
for C33H53NPIr 687.35443; found 687.35474.
[Cp *(XyNC)Ir dP Mes*] (14). 14 was prepared from 5a
(135 mg, 0.20 mmol), DBU (59.8 µL, 0.40 mmol), and XyNC
(26.3 mg, 0.20 mmol) as large dark pink-red crystals (137 mg,
0.186 mmol, 93%). Mp: 151-154 °C. 31P NMR (C6D6): δ 757.1
1
(s, IrdP). H NMR (C6D6): δ 1.18 (s, 9H, p-C(CH3)3), 1.66 (s,
18H, o-C(CH3)3), 2.05 (s, 15H, C5(CH3)5), 2.14 (s, 6H, XyCH3),
6.76 (s, 3H, m,p-Xy), 7.33(s, 2H, m-Mes*). 13C{1H} NMR
(C6D6): δ 10.1 (s, C5(CH3)5), 19.5 (s, XyCH3), 31.7 (s, p-C(CH3)3),
4
32.6 (d, J PC ) 6.9 Hz, o-C(CH3)3), 34.5 (s, p-C(CH3)3), 38.8 (s,
o-C(CH3)3), 96.7 (s, C5(CH3)5), 120.9 (s, m-Mes*), 125.9 (s, p-Xy),
127.7 (s, m-Xy), 131.2 (bs, i-Xy), 134.7 (s, o-Xy), 145.2 (s,
p-Mes*), 146.9 (s, o-Mes*), 154.6 (bs, CN), 166.8 (d, 1J PC ) 93.7
Hz, i-Mes*). IR (KBr, cm-1): ν(CN) 2064, 2023. HRMS: calcd
for C37H53NPIr 735.35443; found 735.35360.
[Cp *(CO)Ir dP Mes*] (15). 15 was prepared from 5a (250
mg, 0.37 mmol), DBU (112 µL, 0.75 mmol), and carbon
monoxide (which was passed through the reaction mixture)
as deep red crystals (205 mg, 0.325 mmol, 88%). Mp: 156-
157 °C. 31P NMR (C6D6): δ 804.6 (s, IrdP). 1H NMR (C6D6): δ
1.43 (s, 9H, p-C(CH3)3), 1.56 (s, 18H, o-C(CH3)3), 1.90 (s, 15H,
C5(CH3)5), 7.49 (s, 2H, m-Mes*). 13C{1H} NMR (C6D6): δ 9.75
4
(s, C5(CH3)5), 31.9 (s, p-C(CH3)3), 32.6 (d, J PC ) 7.3 Hz,
o-C(CH3)3), 34.8 (s, p-C(CH3)3), 38.5 (s, o-C(CH3)3), 99.0 (s, C5-
(CH3)5), 121.2 (s, m-Mes*), 145.0 (s, o-Mes*), 148.8 (s, p-Mes*),
164.5 (d, 1J PC ) 89.4 Hz, i-Mes*), 179.0 (s, CO). IR (KBr, cm-1):
ν(CO) 1968 (s). HRMS: calcd for C29H44OPIr 632.27588; found
632.27560.
Ack n ow led gm en t. This work was supported by The
Netherlands Foundation for Chemical Sciences (CW)
with financial aid from The Netherlands Organization
for Scientific Research (NWO). Dr. H. Zappey is ac-
knowledged for measuring high-resolution mass spectra.
Rea ction of 15 w ith CH2I2 a n d CHI3 on NMR Sca le. A
small excess of CH2I2 (0.12 mmol) was added to a dark red
solution of 15 (0.10 mmol) in n-pentane (0.5 mL). The orange-
red precipitate of Cp*(CO)IrI2, formed quantitatively over a
period of 48 h at room temperature, was removed by decanting
the solution and washing the residue twice with n-pentane (1
mL). The combined n-pentane solutions were evaporated to
yield 16 as a yellow solid (16). Performing the reaction with
CHI3 resulted in the formation of orange-colored 17.
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra of
compounds 3, 5a -c, and 6-15. Crystallographic data for
compounds 3 and 15. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM020062T
(28) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF97 program system; Technical Report of the Crystallography
Laboratory: University of Nijmegen, The Netherlands, 1997.
(29) Sheldrick, G. M. SHELXL-97, program for crystal structure
refinement; University of Go¨ttingen: Germany, 1997.
1
Cp *(CO)Ir I2: H NMR (CDCl3): δ 2.20 (s, 15H, C5(CH3)5).
13C{1H} NMR (CDCl3): δ 10.8 (s, C5(CH3)5), 100.2 (s, C5(CH3)5),
164.1 (s, CO). IR (KBr, cm-1): ν(CO) 2018 (s). 16: 31P NMR
(CDCl3): δ 289.7 (t, 2J PH ) 30.4 Hz). 1H and 13C NMR were as
reported in the literature.22 17: 31P NMR (CDCl3): δ 310.2 (d,
(30) Spek, A. L. PLATON, a multipurpose crystallographic tool;
Utrecht University: The Netherlands, 2001.