Iridium Half-Sandwich Complexes with Di- and Tridentate Bis(pyridylimino)isoindolato Ligands: Stoichiometric and Catalytic Reactivity

Article abstract of DOI:10.1021/om501138t

A series of κ²-(N,N)-coordinated bis(2-pyridylimino)isoindolato (BPI) complexes [CpIr(BPI)Cl], which possess "three-legged piano-stool" structures, with the iridium atom being coordinated by the Cp ligand 2 × N and Cl, were prepared via deproto

Full text of DOI:10.1021/om501138t

Article
pubs.acs.org/Organometallics
Iridium Half-Sandwich Complexes with Di- and Tridentate
Bis(pyridylimino)isoindolato Ligands: Stoichiometric and Catalytic
Reactivity
̈
Astrid L. Muller, Tim Bleith, Torsten Roth, Hubert Wadepohl, and Lutz H. Gade*
̈
Anorganisch-Chemisches Institut, Universitat Heidelberg, Im Neuenheimer Feld 276, 69120 Heidelberg, Germany
*
S Supporting Information
2
ABSTRACT: A series of κ -(N,N)-coordinated bis(2-pyridylimino)-
isoindolato (BPI) complexes [Cp*Ir(BPI)Cl], which possess “three-legged
piano-stool” structures, with the iridium atom being coordinated by the
Cp* ligand 2 × N and Cl, were prepared via deprotonation of the BPIH
ligands with either potassium hydride or LDA and subsequent reaction
+
with [Cp*IrCl ] in THF. Cationic complexes [Cp*Ir(BPI)] containing
2
2
3
κ -(N,N,N)-coordinated BPI ligands were prepared as well as complexes
with bidentate-coordinated BPI ligands, where the chloride ligand was
substituted by either neutral or anionic ligands. Substitution in the ortho-
3
position of the PBI ligands led to the formation of cycloiridated κ -(N,N,C)
species. Upon substitution of the anionic ligand by triphenylphosphine, a
2
product was obtained with a hitherto unobserved κ -(N,N) coordination of
oMe-BPI to the metal center via the deprotonated nitrogen atom of the
isoindole unit and one of the imine nitrogen atoms of the BPI ligand. A series of (para-cymene) osmium half-sandwich
complexes with analogous structures and reactivities to their isoelectronic Cp*Ir(BPI) congeners were also prepared. Finally, it
has been demonstrated that both Ir and Os complexes are catalytically active in the transfer hydrogenation of various ketones and
imines.
INTRODUCTION
Chart 1. Two Different Coordination Modes for BPI Ligands
in Iridium(I) Complexes
■
The coordination chemistry and reactivity of transition metal
complexes is strongly influenced by their ancillary ligands,
which define their steric and electronic properties as well as
1
their stability. Monoanionic meridionally coordinating triden-
tate chelate ligands, frequently referred to as “pincers”, have
been extensively studied as ancillary ligands in organometallic
2
chemistry and molecular catalysis.
Bis(2-pyridylimino)isoindoles (BPIH) are highly modular3,
readily accessible pincers that were first reported in 1952,
while their coordination chemistry has been investigated since
4
the 1970s. To date, BPI complexes with almost the whole
5
−10
range of transition metals have been reported.
BPI ligands
typically coordinate in a meridional tridentate (N,N,N) fashion
to the metal center, as represented by complex A (Chart 1),
although other denticities and coordination modes have also
8
,9
although organometallic iridium(III) compounds in general
display manifold reactivities and offer a range of applications.
17
6
,9,11,12
been observed.
Various examples of applications of BPI
Pentamethylcyclopentadienyl (Cp*) iridium(III) half-sand-
wich complexes have played an important role in the
development of organometallic chemistry. Although the first
complexes in catalysis have been reported, including catalytic
oxidations with iron, cobalt, and ruthenium as well as the
13
14
15
16
18
palladium-catalyzed hydrogenation of CC bonds. Recently,
synthesis of [Cp*IrCl ] was reported in the late 1970s, the
2
2
iridium(I) complexes of the general formula [(BPI)Ir(COD)]
number of Cp*Ir complexes increased dramatically subsequent
(
B) (see Chart 1) have been employed in the catalytic
epoxidation of a wide range of non-electron-rich olefins. In
contrast to the κ -(N,N,N) BPI-coordinated complexes A, the
BPI ligand in B is coordinated in a κ -(N,N) mode to the
iridium center, due to the sterical demand of the COD ligand.
To date, iridium(III) BPI complexes have not been reported,
to the report of a convenient synthesis of this precursor
9
3
Special Issue: Mike Lappert Memorial Issue
Received: November 11, 2014
2
©
XXXX American Chemical Society
A
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2
a
Scheme 1. Synthesis of the κ -(N,N)-Chloro Complexes 1-Cl−5-Cl and Their Isomerization Behavior
a
Reaction conditions: (i) Ligands 1 and 5: KH, THF, rt; [Cp*IrCl ] , −78 °C. (ii) Ligands 2, 3, and 5: LDA, THF, −78 °C; [Cp*IrCl ] , rt. (iii) 4-
2
2
2 2
Cl and 5-Cl: MeOH, rt, 30 min, to give 4[Cl] and 5[Cl]. (iv) 5-Cl: AgOTf, CH Cl , rt, in the dark, to give 5[OTf]. (v) 5-Cl: NaBPh , MeOH, rt, to
2
2
4
give 5[BPh4].
1
9
complex in 1990. Much of the early work in this field was
2
0
devoted to investigations into C−H activation processes.
More recently, the discovery that Cp*Ir complexes are excellent
catalysts for hydrogen transfer reactions has given the field
additional momentum. Complexes bearing additional chelating
21−30
ancillary ligands proved to be particularly promising.
In
contrast, comparatively fewer compounds are known having
31
additional tridentate ligands.
In this paper, we report the preparation of Cp*-iridium half-
sandwich complexes bearing BPI ligands in both bidentate and
tridentate coordination modes, along with a study on the effect
of varying substitution patterns on their coordination chemistry
as well as the way this is reflected in the reactivity of the
complexes. Subsequently, a series of (para-cymene) osmium-
(
II) half-sandwich complexes, showing analogous structures
Figure 1. Molecular structure of [Cp*Ir(oMe-BPI)Cl] (1-Cl)
thermal ellipsoids at 50% probability level). Hydrogen atoms are
omitted for clarity.
and reactivities to their isoelectronic Cp*Ir(BPI) analogues,
were synthesized, and both complexes were found to display
catalytic activity in the transfer hydrogenation of various
ketones and imines.
(
complexes and correspond to the values reported for
RESULTS AND DISCUSSION
21−30
■
structurally related complexes.
As usually observed for
Synthesis of the Chloro Complexes [Cp*Ir(BPI)Cl] (1-
BPI metal complexes, the amido-like N(1)−Ir bond length is
4
Cl−5-Cl) and Isomerization of ortho-Nonsubstituted (R
slightly shorter than the distance associated with the
2
5−7,9
=
[
H) Complexes 4-Cl and 5-Cl. The κ -(N,N)-coordinated
coordinated pyridyl arm N(3)−Ir.
The C(4)−N(4) double
Cp*Ir(BPI)Cl] complexes 1-Cl−5-Cl were prepared via
deprotonation of the BPIH ligands with either potassium
bond of the uncoordinated pyridyl unit adopts an E
configuration with a torsion angle N(1)−C(4)−N(4)−C(14)
of −166.8(2)° (1-Cl), −169.4(2)° (2-Cl), and −174.7(2)° (3-
Cl). Consequently, one of the protons of the isoindole
backbone is located directly above the anisotropy cone of the
pyridyl ring, leading to a chemical shift of 1.30−1.90 ppm to
hydride or LDA and subsequent reaction with [Cp*IrCl ] in
2
2
THF (Scheme 1) and were isolated as orange, air-stable solids
1
13
1
in good yields. The H and C{ H} NMR spectra of 1-Cl−5-
Cl indicate nonsymmetrical coordination of the BPI ligands,
which was also confirmed by single-crystal X-ray structure
analysis of complexes 1-Cl, 2-Cl, and 3-Cl. As a representative
example, the solid-state structure of [Cp*Ir(oMe-BPI)Cl] (1-
Cl) is depicted in Figure 1; selected bond lengths and angles for
all complexes are listed in Table 1.
1
higher field in the H NMR spectrum compared to the free
2
ligand. The analogous effect was observed previously for κ -
9
(N,N)-coordinated [(BPI)Ir(COD)] complexes.
Upon stirring complexes 4-Cl and 5-Cl, which do not
contain any substituents in ortho-position to the pyridine-
4
All three compounds possess “three-legged piano-stool”
structures, with the iridium atom being coordinated by the Cp*
ligand and the three donor atoms N(1), N(3), and Cl. The Ir−
Cp* and Ir−Cl bond lengths are very similar for the three
nitrogen of the BPI ligand (R = H), for 30 min in methanol,
the orange suspension turned into a red solution. Removal of
the solvent gave air-stable, red powders, whose NMR spectra
showed a reduced set of signals for the BPI ligands, indicating
B
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Table 1. Selected Bond Lengths [Å] and Angles [deg] for the Molecular Structures of the Chloro Complexes [Cp*Ir(BPI)Cl]
(1-Cl, 2-Cl, and 3-Cl)
1
-Cl
2-Cl
3-Cl
Ir−N(1)
Ir−N(3)
Ir−Cl(1)
2.0673(17)
2.1551(17)
2.4235(5)
1.7912(9)
85.08(7)
2.057(2)
2.138(2)
2.4036(7)
1.790(1)
83.81(9)
85.88(7)
88.74(6)
−17.7(5)
−169.4(2)
2.074(2)
2.139(2)
2.4166(8)
1.779(1)
83.17(8)
87.84(6)
89.52(6)
8.8(4)
a
Ir−Cp*( )
N(1)−Ir−N(3)
N(1)−Ir−Cl(1)
N(3)−Ir−Cl(1)
N(1)−C(1)−N(2)−C(9)
N(1)−C(4)−N(4)−C(15)
86.41(5)
91.37(5)
−15.7(4)
b
c
−166.8(2)
−174.7(2)
a
b
c
Distance from Ir to Cp* plane. N(1)−C(4)−N(4)−C(18). N(1)−C(4)−N(4)−C(14).
3
+
Figure 2. Solid-state structures of the κ -(N,N,N)-coordinated complex cations [Cp*Ir(BPI] 4[Cl] (left) and 5[Cl] (right) (thermal ellipsoids at
5
0% probability level). Hydrogen atoms are omitted for clarity.
Table 2. Selected Bond Lengths [Å] and Angles [deg] for the Molecular Structures in the Complexes [Cp*Ir(BPI)]X (4[Cl],
5
[Cl], 5[OTf], 5[BPh ])
4
4
[Cl]
5[Cl]
5[OTf]
5[BPh4]
Ir−N(1)
Ir−N(3)
Ir−N(5)
Ir−Cp*( )
Ir−[N,N,N]
2.037(2)
2.115(2)
2.107(2)
1.790(2)
1.319(2)
77.67(9)
76.48(9)
96.07(9)
26.8(4)
2.0276(19)
2.1160(18)
2.1123(19)
1.794(1)
1.283(1)
78.30(8)
79.05(8)
98.43(7)
17.9(3)
2.0313(19)
2.1178(18)
2.1132(18)
1.790(1)
1.299(1)
77.98(7)
77.42(7)
97.86(7)
28.4(3)
2.0341(19)
2.1251(18)
2.113(2)
1.795(1)
1.293(1)
77.37(8)
78.62(7)
98.42(7)
22.6(3)
a
b
N(1)−Ir−N(3)
N(1)−Ir−N(5)
N(3)−Ir−N(5)
c
θ
d
φ
−27.0(4)
−19.8(3)
−23.9(3)
−22.9(3)
d
a
b
c
Distance from Ir to Cp* plane. Molecular plane defined by N(1), N(3), and N(5). Torsion angle C(1)−N(2)−C(9)−N(3). Torsion angle
C(4)−N(4)−C(14)−N(5).
3
their symmetric κ -(N,N,N)-coordination and the formulation
as 4[Cl] and 5[Cl] as represented in Scheme 1.
N(3) and N(5) is slightly longer than to the anionic ligating
nitrogen atom N(1). The iridium atoms are displaced by
1.319(2) Å (4[Cl]) and 1.283(1) Å (5[Cl]) from the
molecular plane defined by the three nitrogens N(1), N(3),
and N(5), which leads to two twisted pyridyl rings of the BPI
ligands, relative to their isoindole backbone.
The reaction of 5-Cl to 5[Cl] was found to take place quite
rapidly in polar solvents, and it was of interest to establish
whether it could be reversed in a nonpolar medium. Heating a
toluene solution of 5[Cl], the reverse reaction was indeed
observed and completed within 2 h. The reversibility of this
To gain insight into the structural details of the complex
geometry in the solid state, single-crystal X-ray structure
analyses of both complexes were carried out (Figure 2).
Selected bond lengths and angles are listed in Table 2. The X-
ray diffraction analysis of 4[Cl] and 5[Cl] established the
3
structural details confirming the κ -(N,N,N)-coordination of
the BPI ligand at the iridium center and the presence of a
nonbonded chloride counterion. As expected, the bond
between the iridium atom and the neutral nitrogen atoms
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Scheme 2. Reactivity of [Cp*Ir(oMe-BPI)Cl] (1-Cl) toward Neutral and Anionic Ligands
isomerization reaction reflects the hemilabile character of the
BPI ligands, which appeared to be promising for the application
in catalytic reactions presented below.
coordinated acetonitrile are observed more downfield from
free acetonitrile. It was not possible to obtain single crystals of
1-MeCN[BPh ] suitable for X-ray diffraction analysis. How-
4
3
The κ -(N,N,N)-coordination in the BPI derivatives could be
ever, by slow diffusion of n-pentane into a saturated solution in
propionitrile, we could obtain crystals of the analogous
propionitrile complex [Cp*Ir(oMe-BPI)(EtCN)]BPh4 (1-
specifically achieved through substitution of the chloride ligands
by weakly coordinating anions. Whereas reaction of 5-Cl with
silver triflate gave [Cp*Ir(tBu-BPI)]OTf (5[OTf]) (Scheme
EtCN[BPh ]), as determined by X-ray diffraction, which is
4
1
), stirring with sodium tetraphenylborate in methanol yielded
shown in Figure 3 along with selected bond distances and
angles. The propionitrile ligand coordinates almost linearly to
the iridium center (Ir−N(6)−C(31) 171.5°) with an Ir−N(6)
distance of 2.081 Å, which is within the normal range for such
[
Cp*Ir(tBu-BPI)]BPh (5[BPh ]), which precipitated as a red
4
4
solid from the reaction mixture. The solid-state structures of
the cations determined by single-crystal X-ray structure analysis
established molecular structures analogous to that of 5[Cl] (see
Supporting Information). No influence of the counterion on
the complex geometries was observed; selected bond lengths
and angles are given in Table 2.
32
complexes.
Whereas the Cp*Ir complex with the ortho-substituted oMe-
3
BPI ligand is incapable of forming a κ -(N,N,N)-coordinated
Cp*Ir(BPI) species because of the steric bulk of the two methyl
3
Reactivity of the ortho-Methyl-Substituted Cp*Ir-
groups, it was possible to generate a tridentate κ -(N,N,C)
(oMe-BPI) Chloro Complex 1-Cl. We had observed that
coordination mode of the BPI ligand. The cyclometalated
complex [Cp*Ir(oMe-BPI′)] (1-BPI′) was obtained as a dark
brown solid in 64% yield from the reaction of the chloro
complex [Cp*Ir(oMe-BPI)Cl] (1-Cl) with sodium hydroxide
in acetonitrile at room temperature (Scheme 2). To gain insight
into the structural details of the complex, single crystals of 1-
BPI′ were grown and characterized by X-ray diffraction. As
shown in Figure 4, the BPI ligand coordinates as a dianionic
ligand with the pyridyl nitrogen atom N(3), the amido nitrogen
atom N(1) of the isoindole unit, and the cyclometalated carbon
atom C(15) of the second pyridyl ring bonded to the iridium
complexes 1-Cl and 2-Cl with ortho-substituted BPI ligands did
not isomerize in polar solvents to the κ -coordinated species
and subsequently found that tridentate (N,N,N) coordination
of the BPI ligand could not be induced by treating a solution of
3
1
-Cl in methanol with chloride abstractors such as NaBPh or
4
KPF . However, using acetonitrile as the solvent generates the
cationic solvate complex [Cp*Ir(oMe-BPI)(MeCN)]BPh (1-
MeCN[BPh ]), which was isolated as an orange, air-stable solid
in 78% yield (Scheme 2). The NMR spectra of 1-
MeCN[BPh ] show similar signal patterns to the chloro
complex 1-Cl, indicating the presence of the κ -(N,N)-
6
4
4
4
2
5
atom. Finally, the η -coordinated Cp* ligand completes the
coordinated BPI ligand. Furthermore, the signals of the
coordination sphere of the half-sandwich complex. Due to the
D
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In order to gain insight into the formation of 1-BPI′, the
reaction between 1-Cl and NaOH was carried out in deuterated
acetonitrile and followed by NMR spectroscopy. The cyclo-
iridation was found to proceed through an intermediate 1-X,
which was formed within a few minutes after the addition of
aqueous sodium hydroxide. In contrast to the observations by
2
Bro
̈
ring et al., the NMR spectra of 1-X indicate a κ -(N,N)-
coordinated species (Figure 5). A possible intermediate, which
Figure 3. Molecular structure of the complex cation in 1-EtCN[BPh4]
(
thermal ellipsoids at 50% probability level). Hydrogen atoms are
omitted for clarity. Selected bond distances [Å] and angles [deg]: Ir−
N(1) 2.057(2), Ir−N(3) 2.134(2), Ir−N(6) 2.081(2), Ir−Cp*
1
.821(1), N(1)−Ir−N(3) 83.45(9), N(1)−Ir−N(6) 82.72(9),
N(3)−Ir−N(6) 88.15(9), Ir−N(6)−C(31) 171.5(2).
1
Figure 5. Aromatic section of the H NMR spectra after addition of
NaOH(aq) to a solution of 1-Cl in CD CN (a) after 5 min: mixture of
3
1
1
-Cl and 1-X; (b) after 25 min: 1-X; (c) after 4 h: mixture of 1-X and
-BPI′; (d) after 9 h: 1-BPI′.
is also in accordance with its 13C{ H} spectrum, might be the
hydroxo complex [Cp*Ir(oMe-BPI)(OH)], resulting from
abstraction of the chloro ligand. Unfortunately, all attempts
to isolate this species failed, and 1-BPI′ was obtained after
workup as the sole product.
Next, we investigated the substitution of the chloride ligand
of complex [Cp*Ir(oMe-BPI)Cl] (1-Cl) by other anionic
ligands, a transformation that proved impossible to control for
1
Figure 4. Molecular structure of the cyclometalated complex 1-BPI′
(
thermal ellipsoids at 50% probability level). Hydrogen atoms are
omitted for clarity. Selected bond distances [Å] and angles [deg]: Ir−
N(1) 2.036(3), Ir−N(3) 2.182(3), Ir−C(15) 2.089(3), Ir−Cp*
1
.824(1), N(1)−Ir−N(3) 79.41(10), N(1)−Ir−C(15) 80.95(11),
N(3)−Ir−C(15) 104.55(11), C(4)−N(4)−C(14) 118.9(3), C(1)−
N(2)−C(9) 120.1(3).
5
-Cl and only led to the formation of the tridentate-
rigid structure of the BPI ligand, the interbond angles N(1)−
Ir−N(3) (79.4°) and N(1)−Ir−C(15) (81.0°) are considerably
smaller than the angle N(3)−Ir−C(15) (104.6°) between the
iridium atom and the pyridyl nitrogens. The NMR spectra of 1-
BPI′ in CD Cl are consistent with its structure in the solid
coordinated, cationic BPI complexes [Cp*Ir(tBu-BPI)]X (X
= OTf, Br, I). Treating a solution of 1-Cl in acetone with
sodium iodide readily afforded halide exchange and the
generation of [Cp*Ir(oMe-BPI)I] (1-I) (Scheme 2). The
molecular structure of 1-I is shown in Figure 6 along with
selected bond distances and angles. It confirms a three-legged
piano-stool configuration around the metal center similar to the
one observed for the chloro complex 1-Cl, with an Ir−I
distance of 2.7129 Å.
2
2
state. As expected, resonances for nine aromatic protons are
1
observed in the H NMR spectra, with the signals of the N-
coordinated side arm being detected at similar chemical shifts
1
3
1
to those of the chloro complex 1-Cl. In the C{ H} NMR
spectrum, the signal of the cyclometalated carbon atom is
Addition of triphenylphosphine and thallium hexafluoro-
phosphate to a solution of 1-Cl in THF gave the cationic
phosphine complex [Cp*Ir(oMe-BPI)(PPh )]PF (1-
observed at 122.4 ppm. In recent studies by Wicholas and
3
Bro
̈
ring, an analogous κ -(N,N,C)-coordination mode of the
3
6
BPI ligand in square planar palladium complexes [Pd(oMe-
PPh [PF ]) as an air-stable, orange solid in 62% yield. The
3 6
BPIH′)X] (X = Cl, OAc) has been described, resulting from
formulation of 1-PPh [PF ] as depicted in Scheme 2 was
3
6
6
,11
sterical strain by terminal methyl groups.
In these cases, the
confirmed by the observation of the molecular ion peaks [M −
3
+
reaction proceeds through a symmetrical κ -(N,N,N)-coordi-
nated species, which is converted to the cyclopalladated
complex by pyridine ring rotation and subsequent C−H
PF ] in the HR FAB mass spectra and an X-ray diffraction
6
analysis (Figure 7). The molecular structure of 1-PPh [PF ]
3
6
illustrates a hitherto unobserved bidentate coordination of
oMe-BPI to the iridium center via the deprotonated nitrogen
6
activating of the heteroaromatic ligand.
E
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mass spectra as well as elemental analysis were in accordance
with the formation of [Cp*Ir(oMe-BPI)(N )] (1-N ) (Scheme
3
3
2
), containing an azido ligand and the BPI ligand in a bidentate
binding mode. The characteristic ν(N ) band was detected at
2
3
034 cm− in the IR spectrum (ν(NaN ) = 2140 cm ).
1
−1 37
3
Single crystals of the azido complex 1-N were analyzed by X-
3
ray diffraction, and its molecular structure is depicted in Figure
8
. There are two independent molecules in the unit cell, which
Figure 6. Solid-state structure of 1-I (thermal ellipsoids at 50%
probability level, hydrogen atoms are omitted for clarity). Selected
bond lengths [Å] and angles [deg]: Ir−N(1) 2.061(6), Ir−N(3)
2
.158(5), Ir−I 2.713(1), Ir−Cp* 1.798(3), N(1)−Ir−N(3) 83.7(2),
N(1)−Ir−I 86.92 (17), N(3)−Ir−I 95.25(18).
Figure 8. Molecular structure of 1-N3 (thermal ellipsoids at 50%
probability level, only one of the two independent molecules is
shown). Hydrogen atoms are omitted for clarity. Selected bond
distances [Å] and angles [deg], values in square brackets refer to the
second independent molecule: Ir(1)−N(1) 2.066(3) [2.064(3)],
Ir(1)−N(3) 2.154(3) [2.142(3)], Ir(1)−N(6) 2.118(3) [2.119(3)],
N(6)−N(7) 1.194(4) [1.193(4)], N(7)−N(8) 1.162(4) [1.158(4)],
Ir−Cp* 1.790(2) [1.792(2)], N(1)−Ir(1)−N(3) 82.62(10)
[
(
[
83.81(11)], N(1)−Ir(1)−N(6) 84.98(11) [85.04(11)], N(3)−Ir-
1)−N(6) 87.30(11) [86.86(11)], Ir(1)−N(6)−N(7) 121.2(2)
125.2(2)], N(6)−N(7)−N(8) 176.3(4) [174.4(4)].
mainly differ in the rotational orientation of the Cp* ligand and
the free o-Me pyridyl arm. As expected, the azido ligand
coordinates to the iridium center in a bent fashion (Ir−N(6)−
N(7) 121° and 125°). The Ir−N(6) bond length of 2.12 Å lies
Figure 7. Solid-state structure of the complex cation in 1-PPh [PF ]
3
6
(
thermal ellipsoids at 50% probability level). Hydrogen atoms are
omitted and the phenyl rings of the PPh ligand are represented by the
3
ipso-C atoms for clarity. Selected bond lengths [Å] and angles [deg]:
Ir−N(1) 2.131(3), Ir−N(2) 2.130(3), Ir−P(1) 2.3258(12), Ir−Cp*
38,39
within the normal range for similar complexes.
Heating a solution of 1-N in toluene led to nonselective
3
1
.821(2), N(1)−Ir−N(2) 61.22(13), N(1)−Ir−P(1) 87.25(10),
decomposition of the complex, whereas photolysis with a Hg
lamp at room temperature selectively converted 1-N3 to
N(2)−Ir−P(1) 91.46(10), N(1)−C(1)−N(2) 108.6(4), N(1)−
C(4)−N(4) 120.7(4).
[
Cp*Ir(oMe-BPI)(N)] (1-N), which could be isolated as a
dark green solid in 92% yield (Scheme 3). Single-crystal X-ray
atom N(1) of the isoindole unit and one of the imine nitrogen
atoms, N(2), of the BPI ligand. This may be due to the steric
diffraction of 1-N indicated that photolysis of 1-N led to
3
elimination of N and the formation of an essentially planar
2
bulk of the PPh ligand and its interference with the ortho-
3
(
rmsd 0.017 Å) five-membered iridacycle bearing a N−N
substituted pyridyl ring of the BPI.
chelate ligand (Figure 9). The new chelate ligand is coordinated
to the iridium atom via the isoindole nitrogen atom N(1) and
the nitrogen atom N(3) derived from the azido ligand, which is
Compared to the coordination via the pyridine nitrogen
atom N(3) in, for example, 1-Cl, the unusual coordination via
N(2) reduces steric strain between the phosphine ligand and
the pyridyl ring of the coordinated side arm of the BPI ligand.
The NMR spectra of 1-PPh [PF ] are consistent with the
Scheme 3. Photolysis of Azido Complex 1-N3
3
6
unsymmetrical coordination mode of the BPI ligand as well as
the presence of an unidentified, minor isomer (18%).
Due to their reactivity, azido complexes of late transition
metals represent interesting starting materials for the synthesis
33−35
of new reactive compounds.
Recently, the first terminal
iridium nitrido complexes were prepared by Burger and
Schneider via thermolysis or photolysis of the corresponding
36
iridium azido complexes. When a methanolic solution of
chloro complex 1-Cl and sodium azide was stirred for 2 h at
room temperature, an orange solid was obtained. NMR, IR and
F
DOI: 10.1021/om501138t
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Organometallics
Article
an iridium(I) diazenido (a) and an iridium(III) hydrazinediido
species (b, c) represented in Scheme 4.
Scheme 4. Resonance Structures of the Possible Binding
Modes in 1-N
In order to further elucidate the electronic structure of the
iridacycle, the complex was modeled by DFT. Two scenarios
were considered in detail that are based on an 18 electron
count for iridium: either Ir(I) is coordinated to a Cp* ligand
and has two dative single bonds to an uncharged BPI ligand or
Ir(III) receives six electrons from the two N-donors in addition
to the six electrons shared with the Cp* ligand (see Scheme 4).
For comparison, two reference molecules were considered,
[Cp*Ir(NH) ] and [Cp*Ir(NH ) (NH )], which possess
Figure 9. Molecular structure of 1-N (thermal ellipsoids at 50%
probability level). Hydrogen atoms are omitted for clarity. Selected
bond distances [Å] and angles [deg]: Ir(1)−N(1) 1.994(3), Ir(1)−
N(3) 1.926(3), Ir(1)−Cp* 1.823(2), N(2)−N(3) 1.378(4), N(2)−
C(1) 1.334(5), C(1)−N(1) 1.352(5), N(1)−C(4) 1.419(5), C(4)−
N(5) 1.274(5), N(1)−Ir(1)−N(3) 79.74(13), N(1)−C(1)−N(2)
2
2
2
3
1
12.8(3), N(3)−N(2)−C(1) 118.3(3), C(1)−N(2)−N(3)−Ir(1)
oxidation states of +I and +III, respectively. NPA showed a
slightly positive charge for Ir in 1-N (+0.32e) that is in the usual
range for Ir(III) complexes. With the help of NBO analysis,
three nonbonding electron pairs were assigned to the Ir center
in compound 1-N as well as in the Ir(III) reference compound,
while in the Ir(I) reference four nonbonding pairs were found.
Moreover, Wiberg bond indices (WBIs) for the Ir−N bonds
showed that there is a multiple bond between the Ir center and
N(3) (WBI: 1.107) and a single bond between Ir and N(1)
(WBI: 0.658). Second-order contributions as well as the
orientation of the orbitals indicate an iridacycle with delocalized
electrons. All of these findings strongly support that the
resonance structure corresponding to the Ir(III) complex c best
represents the bonding (Scheme 4). This is also in good
agreement with the previous interpretation for comparable
−
1.0(4), N(2)−C(1)−N(1)−Ir(1) −4.4(4), N(3)−N(2)−C(1)−
N(1) 3.5(5).
bonded to the imino nitrogen atom N(2) of the BPI ligand.
The NMR spectra of 1-N are consistent with its structure in the
solid, and, in particular, the singlet of the Cp* protons in the
1
H NMR spectrum is observed at 2.01 ppm, hence 0.81 ppm
downfield compared to the corresponding resonance in 1-N . A
3
similar chemical shift for the Cp* ligand was found for other
Cp*Ir half-sandwich complexes with only an additional
3
4,38,40,41
bidentate chelate ligand in their coordination sphere.
Mayer and Suzuki previously reported that photolysis of
Cp*Ir azido complexes [Cp*Ir(S CNR or 2-Spy)(N )]
2
2
3
(
S CNR = N,N-dialkyldithiocarbamate; 2-Spy = 2-pyridine-
2 2
3
8,41
thiolate) afforded similar five-membered iridacycles by
iridacycles by Meyer et al. and Suzuki et al.
elimination of N and insertion of a nitrogen atom of the
In Figure 10 orbitals that contribute to the non-σ-bonding of
the iridacycle are shown. As required for an aromatic ring, Ir
2
3
8,41
azide into the Ir−S or Ir−N(py) bond.
The bond lengths of
the planar chelate ring were described as intermediate between
typical single and double bonds, and the metallacycles were
interpreted as iridacyclopentadienyl-like moieties. The molec-
ular structure of [Cp*Ir(oMe-BPI)(N)] (1-N) (see Figure 9)
also provides support for an electron-delocalized five-
membered chelate ring. The bonds Ir(1)−N(1) (1.994 Å)
and Ir(1)−Ir(N3) (1.926 Å) are shorter than Ir−N single
contributes with its d -orbital to the π-system (see orbitals
xz
2
2
π(N(1)−Ir) and HOMO−1), while the filled d -, d -, and
d -orbitals are nonbonding at the iridium center. Since the
xy
x −y
2
z
interaction between the p-orbital at N(1) and the d -orbital at
xz
Ir is small, the antibonding MO to π(N(1)−Ir) is also occupied
(HOMO−1). Therefore, the N(1)−Ir bond is best described as
a single bond, but the lone pair at N(3) (HOMO−4) also has
the appropriate symmetry to interact with the iridium center.
This interaction, not explicitly depicted in the natural bond
orbitals of Figure 10, renders the Wiberg bond index between
N(3) and Ir larger than 1.
42−44
bonds in iridium diazenido complexes (2.008−2.050 Å)
but longer than the typical values for Cp*Ir(imido) complexes
4
5
(
∼1.73 Å). Furthermore, they were found to be similar to the
reported Ir−N distances of the iridacycles characterized by
Mayer and Suzuki (1.911 and 1.946 Å).
distance (1.378 Å) is intermediate between single and double
3
8,41
The N(3)−N(2)
Isomerization Behavior and Reactivity of the ortho-
Fluorine-Substituted Cp*Ir(oF-BPI) Chloro Complex 3-
Cl. We found that there is a subtle influence of the substituent
in ortho-position of the BPI pyridyl ring on the isomerization
and reaction behavior of the Cp*Ir(BPI) complexes. The oF-
BPIH ligand (3) possesses a fluorine substituent in ortho-
position, whose sterical demand lies between the ones of a
proton and a methyl group. In analogy with the complexes 4-Cl
and 5-Cl, we examined the isomerization of [Cp*Ir(oF-BPI)Cl]
bonds involving the corresponding atoms (NN(diazenido):
4
2−44
46
1
(
.20−1.28 Å;
N−N(hydrazine): 1.47 Å;
N−N-
47
pyridazine): 1.346 Å ). Finally, the C−N bonds N(1)−
C(1) (1.352 Å) and N(2)−C(1) (1.334 Å) were also found to
lie in the normal range between amine and imine bonds
(
compare 1-N : N(1)−C(4) 1.400(4) [1.405(4)] Å; N(2)
3
C(1) 1.306(4) [1.296(4)] Å and N(4)C(4) 1.268(4)
[
1.283(4)] Å). In principal, the structure of compound 1-N
(3-Cl) in methanol-d by NMR spectroscopy. Instantaneously
4
19
1
appears to be best represented by the resonance structures of
after dissolving the complex, the F{ H} NMR spectrum
G
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Article
Figure 11. 19F{ H} NMR spectrum: equilibrium between the (N,N)-
and the (N,N,N)-coordinated species 3-Cl and 3[Cl] at rt in
methanol-d4.
1
Scheme 5. Isomerization Behavior of 3-Cl in Methanol and
Synthesis of 3[BPh ] and 3-N
4
3
Figure 10. Selected natural bond orbitals of 1-N. All orbitals depicted
participate in the non-sigma-bonding of the iridacycle. HOMO,
LUMO, and LUMO+1 are not shown, because they describe parts of
the Ir−Cp* interaction.
2
displayed the two signals of the κ -(N,N)-coordinated species
3
3
(
(
-Cl (−53.91 and −71.01 ppm) as well as one signal of the κ -
N,N,N)-coordinated complex [Cp*Ir(oF-BPI)]Cl 3[Cl]
−52.23 ppm) (Figure 11). After 15 min, an equilibrium
between the two species appeared, and the ratio of these two
−1
isomers changed with the temperature [ΔS = 39.3 ± 1.4 J K
−1
−1
mol , ΔH = 9.6 ± 0.5 kJ mol ]. The experimentally
determined thermodynamic data show that the κ -coordinated
2
species 3-Cl is enthalpically slightly favored in methanol. On
3
the other hand, the κ -coordinated, ionic species 3[Cl] is
entropically strongly favored.
Treatment of a solution of 3-Cl/3[Cl] in methanol with
3
sodium tetraphenylborate led to the clean formation of κ -
coordinated complex [Cp*Ir(oF-BPI)]BPh (3[BPh ]) as a red
4
4
Figure 12. Molecular structure of the complex cation [Cp*Ir(oF-
solid in 93% yield (Scheme 5). Single crystals suitable for X-ray
+
BPI)] in 3[BPh ] (thermal ellipsoids at 50% probability level).
4
diffraction were obtained by slow diffusion of n-pentane in a
Hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and
concentrated solution of 3[BPh ] in dichloromethane at 7 °C
4
angles [deg]: Ir−N(1) 2.056(2), Ir−N(3) 2.115(2), Ir−N(5)
3
(Figure 12). The BPI ligand is again κ -(N,N,N)-coordinated at
2
.187(2), Ir−Cp* 1.786(1), N(1)−Ir−N(3) 77.23(8), N(1)−Ir−
the iridium atom, the bond angle N(3)−Ir−N(5) (104.80°)
N(5) 78.25(8), N(3)−Ir−N(5) 104.80(8).
being slightly larger than in 5[Cl], 5[OTf], and 5[BPh ]
4
(around 98°). This can be attributed to the stronger sterical
H
DOI: 10.1021/om501138t
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Organometallics
Article
2
3
repulsion between the pyridyl rings due to the fluorine
Scheme 6. Synthesis of κ -(N,N)- and κ -(N,N,N)-
a
substituents.
Coordinated Osmium Half-Sandwich Complexes
2
Finally the κ -coordination of oF-BPI could be enforced by
treatment of a solution of 3-Cl/3[Cl] in methanol with sodium
azide at room temperature. The product [Cp*Ir(oF-BPI)(N )]
3
(
3-N ) was isolated as an orange, air-stable solid in 76% yield.
3
The IR spectrum of 3-N proves the coordination of the azido
3
ligand and exhibits the characteristic ν(N ) band at the same
3
−1
wavenumber as in 1-N (2034 cm ). The NMR spectra display
3
two sets of signals for the BPI ligand, indicating the presence of
2
a κ -(N,N)-coordinated BPI complex. The structural assign-
ment based on the spectroscopic data could be confirmed by
single-crystal X-ray structure analysis for azido complex 3-N3
(Figure 13).
a
Reaction conditions: (i) LDA, THF, −78 °C; [(p-Cym)OsCl ] , rt.
2
2
(
ii) 7-Cl: MeOH, 30 min, rt, to form 7[Cl]. (iii) 7[Cl]: NaBPh ,
4
MeOH, rt, to afford 7[BPh4].
Figure 13. Molecular structure of [Cp*Ir(oF-BPI)(N )] (3-N )
3
3
(
thermal ellipsoids at 50% probability level). Hydrogen atoms are
omitted for clarity. Selected bond lengths [Å] and angles [deg]: Ir−
N(1) 2.0668(15), Ir−N(3) 2.1425(16), Ir−N(6) 2.1122(16), N(6)−
N(7) 1.200(2), N(7)−N(8) 1.158(2), Ir−Cp* 1.785(1), N(1)−Ir−
N(3) 82.75(6), N(1)−Ir−N(6) 87.53(7), N(3)−Ir−N(6) 84.44(6),
N(6)−N(7)−N(8) 174.89(19), Ir−N(6)−N(7) 122.17(13).
Synthesis and Reactivity of Osmium(II) Half-Sandwich
Complexes Bearing BPI Ligands. Given the interesting
coordination chemistry and reactivity of the Cp*Ir(BPI)
complexes, we synthesized a series of isoelectronic (para-
cymene) osmium(II) half-sandwich complexes (p-Cym)Os-
(BPI). Reaction of the protio ligands oF-BPIH (3) and tBu-
BPIH (5) with LDA and, subsequently, with the osmium
precursor [(p-Cym)OsCl2]2 led to the formation of the
complexes [(p-Cym)Os(BPI)Cl] 6-Cl and 7-Cl as dark red
Figure 14. Molecular structure of the complex cation [(p-Cym)Os-
+
(tBu-BPI)] in 7[BPh ] (thermal ellipsoids at 50% probability level).
4
solids in 69% (6-Cl) and 82% (7-Cl) yield, respectively
Hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and
1
(Scheme 6). The H NMR spectra of 6-Cl and 7-Cl display the
angles [deg]: Os−N(1) 2.0419(17), Os−N(3) 2.1231(17), Os−N(5)
2
.1208(18), Os−Cym 1.679(1), N(1)−Os−N(3) 76.98(7), N(1)−
typical patterns of four diastereotopic doublets of the aromatic
para-cymene protons between 6.12 and 5.62 ppm, due to the
stereogenic osmium center. For compound 6-Cl, two signals
Os−N(5) 77.83(7), N(3)−Os−N(5) 94.39(6).
1
9
1
are detected in the F{ H} NMR spectrum at −68.24 and
coordination of the BPI ligand, similar to the corresponding
−
47.97 ppm, the latter representing the fluorine atom of the
[Cp*Ir(BPI)]X complexes 5[Cl], 5[OTf], and 5[BPh ], as
4
coordinated BPI pyridyl unit. The formulation of 6-Cl and 7-Cl
as depicted in Scheme 6 was confirmed by the observation of
illustrated in Figure 14. The Os−N(1) distance of 2.0419 Å is
slightly shorter than the distances between the osmium center
and the neutral pyridine nitrogen atoms N(3) and N(5)
(2.1231 and 2.1208 Å), as observed in the Cp*Ir(III)
complexes discussed above.
+
the molecular ion peaks [M + H] in their HR DART mass
spectra. Complex 7-Cl was found to isomerize in methanol,
3
yielding the cationic, κ -(N,N,N)-coordinated species [(p-
Cym)Os(tBu-BPI)]Cl (7[Cl]) (Scheme 6), and addition of
sodium tetraphenylborate gave [(p-Cym)Os(tBu-BPI)]BPh4
Catalytic Transfer Hydrogenation of Ketones and
Imines with Cp*Ir(BPI) and (p-Cym)Os(BPI) Complexes.
The application of transfer hydrogenation catalysts based on
half-sandwich Cp*Ir complexes was first reported in 1999 by
(
7[BPh ]) via anion exchange. Single crystals of 7[BPh ]
4
4
were obtained, and X-ray diffraction confirmed the tridentate
I
DOI: 10.1021/om501138t
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Article
4
8
Ikariya and Noyori. Since then, a multitude of diverse Cp*Ir
Table 4. Transfer Hydrogenation of Various Ketones and
Imines Catalyzed by 3-Cl
a
systems has been published that are easily accessible and
versatile precatalysts for this reaction. Complexes 1-Cl, 3-Cl,
-Cl, and 7-Cl were tested as precatalysts for activity in the
49
5
transfer hydrogenation of ketones and imines from iPrOH/
KOH at 80 °C. In a first screening of the catalytic performance,
we examined the reduction of cyclohexanone and acetophe-
none with catalyst loadings of 5 mol %. Both ketones were
converted to the corresponding alcohols in goodin the case
of 3-Cl and 7-Cl in quantitativeyields within 1 or 2 h of
reaction time (Table 3). The Cp*Ir(BPI) complex 3-Cl
displayed the highest catalytic activity for both substrates and
was used in the subsequent reactions.
Table 3. Transfer Hydrogenation of Ketones Catalyzed by
Cp*Ir(BPI) and (p-Cym)Os(BPI) Half-Sandwich
a
Complexes
NMR yield [%]
entry
substrate
catalyst
t = 1 h
t = 2 h
1
2
3
4
5
6
7
8
cyclohexanone
1-Cl
3-Cl
5-Cl
7-Cl
1-Cl
3-Cl
5-Cl
7-Cl
68
>99
38
85
74
>99
98
89
acetophenone
92
96
>99
68
51
97
>99
a
Reaction conditions: Substrate (0.4 mmol, 1.0 equiv), KOH (0.2
a
Reaction conditions: Ketone (0.2 mmol, 1.0 equiv), KOH (0.1 mmol,
.5 equiv), catalyst (0.01 mmol, 5 mol %), and 1,3,5-trimethox-
ybenzene (TMB) (0.05 mmol, 0.25 equiv) reacted in 1.0 mL of iPrOH
at reflux temperature. Yields were determined by H NMR
spectroscopy relative to TMB as internal standard.
mmol, 0.5 equiv), 3-Cl (0.004 mmol, 1 mol %), and 1,3,5-
trimethoxybenzene (TMB) (0.1 mmol, 0.25 equiv) reacted in 1.0
mL of iPrOH at reflux temperature. Yields were determined by H
NMR spectroscopy relative to TMB as internal standard. Reactant
0
1
1
b
was completely consumed.
Under the optimized reaction conditions (see Supporting
Information) and a catalyst loading of 1 mol %, compound 3-Cl
was tested in the hydrogen transfer of a series of ketones (Table
2
ligand in a hitherto unobserved κ -(N,N)-coordination of oMe-
BPI to the metal center via the deprotonated nitrogen atom of
the isoindole unit and one of the imine nitrogen atoms of the
BPI ligand. Furthermore, we synthesized a series of (para-
cymene) osmium half-sandwich complexes, showing analogous
structures and reactivities to their isoelectronic Cp*Ir(BPI)
congeners. Finally, we demonstrated that both Ir and Os
complexes are catalytically active in the transfer hydrogenation
of various ketones and imines.
4
), which were converted to the corresponding hydrogenated
species in good yields. Transfer hydrogenation of imines
afforded the corresponding amines in low to moderate yields.
The lower activity of the Cp*Ir(BPI) catalyst in these reactions
may be due to the fact that both imines and the generated
amines can act as competing ligands and thus deactivate the
catalytically active species (substrate and product inhibition).
EXPERIMENTAL SECTION
CONCLUSIONS
■
■
General Procedures and Materials. All manipulations, except as
indicated otherwise, were carried out under an inert gas atmosphere by
using standard Schlenk techniques or a glovebox. Argon 5.0, purchased
from Messer Group GmbH, was used after drying over Granusic
phosphorus pentoxide (granulated). Solvents were dried over activated
alumina columns by using a solvent purification system (M. Braun SPS
In summary, we have synthesized Cp*-iridium half-sandwich
complexes bearing BPI ligands in various coordination modes.
2
Starting from κ -(N,N)-coordinated chlorido complexes
[
Cp*Ir(BPI)Cl], the effect of varying substitution patterns of
the BPI ligands on the coordination chemistry was studied,
showing a subtle influence on the reactivity of the complexes
depending on the substituent in ortho-position of the pyridyl
50
800) or according to standard literature procedures and degassed
and stored in glass ampules under an argon atmosphere. Diethyl ether
and n-pentane were distilled from sodium/potassium alloy, tetrahy-
drofuran and benzene from potassium, methanol from magnesium,
dichloromethane and chloroform from calcium hydride, and toluene
from sodium. The same procedures were used to dry the deuterated
solvents. Degassed solvents were obtained by three successive freeze−
pump−thaw cycles. NMR spectra were recorded on Bruker Advance II
(400 MHz) and Bruker Advance III (600 MHz) spectrometers.
Chemical shifts (δ) are reported in parts per million (ppm) and are
+
nitrogen atom. Cationic complexes [Cp*Ir(BPI)] containing
κ -(N,N,N)-coordinated BPI ligands were prepared as well as
complexes with bidentate coordinated BPI ligands, where the
chloride ligand was substituted by either neutral or anionic
ligands. In this context, we also obtained the cycloiridated κ -
3
3
(
N,N,C)-coordinated compound 1-BPI′ as well as the
phosphine complex 1-PPh [PF ], which contains the BPI
3
6
J
DOI: 10.1021/om501138t
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Organometallics
Article
1
0
10
13
13
referenced to the residual proton or carbon signals of the solvents in
22.5 (C /C ′), 18.3 (C ′), 17.9 (C ), 9.12 (C(CH ) Cp*). HRMS
3
1
13
1
51
19
1
31
1
+
+
the case of H and C{ H} NMR spectra. For F{ H} and P{ H}
NMR spectra, H PO and CCl F were used as external standards,
(ESI ): m/z calcd for C H ClIrN ([M + H] ) 770.2596; found
36 40 5
770.2594. Anal. (%) Calcd for C H ClIrN : C 56.20, H 5.11, N 9.10.
3
4
3
36 39
5
respectively. The following abbreviations were used: s (singlet), d
doublet), t (triplet), sept (septet), and m (multiplet). For atom
numbering of the BPI ligands and the para-cymene ligand, see
Supporting Information. High-resolution mass spectra were acquired
on Bruker ApexQe hybrid 9.4 T FT-ICR (ESI, DART) and Jeol JMS-
Found: C 56.39, H 5.38, N 8.95.
(
[Cp*Ir(oF-BPI)Cl] (3-Cl). The synthetic procedure of this compound
was the same as that of 2-Cl, using oF-BPIH (3) (200 mg, 0.597
mmol) instead of pentBPIH to give 3-Cl as an orange, air-stable solid.
Crystals suitable for an X-ray diffraction study were obtained from
slow diffusion of n-pentane in a solution of 3-Cl in dichloromethane at
7
00 magnetic sector (EI, FAB, LIFDI) spectrometers at the mass
1
spectrometry facility of the Institute of Organic Chemistry of
Heidelberg. IR spectra were recorded on an Excalibur 3100 FT-IR
spectrometer by Varian as potassium bromide pellets. Elemental
analyses were carried out in the Microanalysis Laboratory of the
Heidelberg Chemistry Department. Unless otherwise stated, all
chemicals were purchased from commercial suppliers and were used
without further purification. The following compounds were
7 °C. Yield: 322 mg, 77%. H NMR (600.1 MHz, C D , 295 K): δ
6
6
3
2
1
6
7
(ppm) = 8.08 (d, J = 7.5 Hz, 1H, H ), 6.96 (m, 3H, H , H , H ′),
HH
7
1
2
6
6.78 (m, 1H, H ), 6.72 (m, 1H, H ′), 6.66 (m, 2H, H ′, H ′), 6.22 (d,
3
8
3
8
J
= 7.9 Hz, 1H, H ′), 5.91 (d, J = 7.7 Hz, 1H, H ), 1.37 (s, 15H,
13 1
HH
HH
Cp*). C{ H} NMR (150.9 MHz, C D , 295 K): δ (ppm) = 163.5 (d,
6
6
1
9
1
9
3
JCF = 237.9 Hz, C ′), 162.8 (d, J = 232.9 Hz, C ), 161.9 (d, J
=
=
CF
CF
5
4
4
5
1
7.02 Hz, C ′), 160.5 (C ′), 158.8 (C ), 156.0 (C ), 141.7 (d, J
CF
5
2
7
3
3
7
3
synthesized according to literature procedures: oMe-BPIH (1),
8.11 Hz, C ′), 140.8 (C ), 140.6 (d, J = 10.4 Hz, C ), 131.9 (C ′),
CF
5
3
Me
9
54
19
1
1
2
2
4
pentBPIH (2), Xyl-BPIH (4), tBu-BPIH (5), [Cp*IrCl ] ,
130.3 (C ), 129.7 (C ′), 124.1 (C ′), 121.7 (C ), 119.6 (d, J = 3.7
2
2
CF
55
6 4 6 2 8
[
(p-Cym)OsCl ] . For synthesis and characterization of oF-BPIH
Hz, C ), 113.0 (d, J = 4.6 Hz, C ′), 103.1 (d, J = 31.2 Hz, C ),
2
2
CF
CF
2
8
(
3) and 1-X, see Supporting Information.
Cp*Ir(oMe-BPI)Cl] (1-Cl). To a solution of oMe-BPIH (1) (308
mg, 0.941 mmol, 1.0 equiv) in THF (12 mL) was added KH (188 mg,
.70 mmol, 5.0 equiv). After stirring for 1 h the reaction mixture was
cooled to −78 °C and [Cp*IrCl ] (413 mg, 0.518 mmol, 0.55 equiv)
102.0 (d, J = 36.8 Hz, C ′), 86.9 (C(CH ) Cp*), 9.1 (C(CH )
CF
3
3
19 1
[
Cp*). F{ H} NMR (376.3 MHz, C D , 295 K): δ (ppm) = −52.3 (s,
6
6
+
F), −68.3 (s, F′). HRMS (ESI ): m/z calcd for C H ClF IrN ([M +
2
8
26
2
5
+
4
H] ) 698.1469; found 698.1467. Anal. (%) Calcd for C H ClF IrN :
28 25 2 5
2
2
C 48.24, H 3.61, N 10.04. Found: C 48.20, H 3.87, N 9.87.
Me
was added. The reaction mixture was stirred overnight at rt, and the
solvent was removed in vacuo. The residue was extracted with toluene
and filtered through a pad of Celite. After evaporation of the solvent,
the crude product was washed with diethyl ether and n-pentane to
afford the product 1-Cl as an orange, air-stable solid. Single crystals
suitable for X-ray diffraction were obtained by slow diffusion of n-
pentane in a solution of 1-Cl in dichloromethane. Yield: 593 mg, 91%.
[Cp*Ir(Xyl-BPI )Cl] (4-Cl). The synthetic procedure of this
Me
compound was the same as that of 2-Cl, using Xyl-BPIH (4)
(50.0 mg, 0.093 mmol) instead of pentBPIH to give 4-Cl as an orange,
air-stable solid. Yield: 56.0 mg, 67%. H NMR (600.1 MHz, CD Cl ,
295 K): δ (ppm) = 8.77 (s, 1H, H ), 8.23 (s, 1H, H ′), 7.98 (m, 2H,
1
2
2
9
9
7
7
2
11
3
H , H ′), 7.71 (s, 1H H ), 7.35 (s, 1H, H ′), 7.32 (d, J = 8.5 Hz,
HH
6
11
6
13
13
1H, H ), 7.27 (s, 1H, H ), 7.09 (m, 3H, H ′, H , H ′), 6.29 (s, 1H,
1
3
2
14
14
14
14
15
H NMR (399.9 MHz, CD Cl , 295 K): δ (ppm) = 7.88 (d, J = 7.4
H ′), 2.45 (s, 6H, H /H ′), 2.44 (s, 6H, H /H ′), 2.38 (s, 3H, H ),
15 13 1
2
2
7
HH
2
7
1
Hz, 1H, H ), 7.60 (m, 2H, H , H ′), 7.42 (m, 1H, H ), 7.20 (m, 1H,
2.10 (s, 3H, H ′), 1.58 (s, 15H, Cp*). C{ H} NMR (150.9 MHz,
1
3
6
3
5 4 4
H ′), 7.13 (d, J = 8.1 Hz, 1H, H ), 6.98 (d, J = 7.5 Hz, 1H,
CD Cl , 295 K): δ (ppm) = 162.1 (C ′), 161.9 (C ′), 159.8 (C ),
5 9 9 1 3 12
HH
HH
2
2
6
3
8
3
H ′), 6.94 (d, J = 7.3 Hz, 1H, H ), 6.78 (d, J = 7.8 Hz, 1H,
155.3 (C ), 151.8 (C ), 147.0 (C ′), 139.9 (C ′/C ′), 139.0 (C /
HH
HH
8
3
2
10
12 1 12 12 1 3 8 8
H ′), 6.40 (d, J = 7.7 Hz, 1H, H ′), 3.03 (s, 3H, H ), 2.52 (s, 3H,
C ′), 138.9 (C ), 138.7 (C /C ′), 138.6 (C ′/C ′), 138.1 (C /C ′),
7 7 8 8 7 7 10
HH
1
0
13
1
H ′), 1.53 (s, 15H, Cp*). C{ H} NMR (100.6 MHz, CD Cl , 295
136.6 (C /C ′), 136.1 (C /C ′), 136.0 (C /C ′), 132.7 (C ), 131.8
10 3 13 13 2
2
2
5
5
9
4
4
K): δ (ppm) = 162.5 (C /C ′), 162.0 (C ), 160.5 (C /C ′), 159.2
(C ′), 130.2 (C ), 129.8 (C ), 129.1 (C ′), 125.5 (C ′), 124.6
11 11 6 2 6
5
5
9
4
4
3
7
7
(
C /C ′), 158.2 (C ′), 157.5 (C /C ′), 140.4 (C ′), 138.4 (C /C ′),
(C ′), 124.3 (C ), 123.0 (C ), 122.2 (C ), 116.0 (C ′), 87.0
7
7
3
1
1
2
14 14 14 14 15
1
1
8
38.1 (C /C ′), 132.7 (C ), 130.4 (C ), 129.8 (C ′), 124.5 (C ′),
(C(CH ) Cp*), 21.3 (C /C ′), 21.3 (C /C ′), 20.5 (C ′), 20.1
15 +
3
6
2
8
2
8
6
8‘
22.1 (C ), 121.7 (C /C ), 121.6 (C /C ), 117.9 (C ′), 112.3 (C ),
(C ), 9.3 (C(CH ) Cp*). HRMS (ESI ) m/z calcd for C H ClIrN
3 46 48 5
+
10
10
7.3 (C(CH ) Cp*), 29.4 (C ), 24.6 (C ′), 9.4 (C(CH ) Cp*).
([M + H] ) 898.3222; found 898.3160. Anal. (%) Calcd for
C H ClIrN : C 61.55, H 5.28, N 7.80. Found: C 61.56, H 5.66, N
3
3
+
+
HRMS (ESI ): m/z calcd for C H ClIrN ([M + H] ) 690.1970;
30
32
5
46 47
5
found 690.1967. Anal. (%) Calcd for C H ClIrN : C 52.28, H 4.53,
7.70.
30
31
5
N 10.16. Found: C 52.39, H 4.23, N 9.72.
Cp*Ir(pentBPI)Cl] (2-Cl). A solution of LDA (39.4 mg, 0.368
[Cp*Ir(tBu-BPI)Cl] (5-Cl). The synthetic procedure of this
compound was the same as that of 1-Cl, using tBu-BPIH (5) (111
mg, 0.270 mmol) instead of oMe-BPIH to give 5-Cl as an orange, air-
stable solid. Yield: 124 mg, 71%. H NMR (600.1 MHz, C
[
mmol, 1.5 equiv) in THF (2 mL) was added to a solution of
pentBPIH (2) (100 mg, 0.245 mmol, 1.0 equiv) in THF (6 mL) at
1
D
, 295 K):
6
6
3
9
3
9
−
78 °C. After the addition was completed the solution was warmed to
room temperature and stirred for another 30 min. Then the reaction
mixture was added dropwise via cannula to a suspension of
δ (ppm) = 8.55 (d, JHH = 6.3 Hz, H ), 8.52 (d, JHH = 5.4 Hz, H ′),
3 2 4 6
8.22 (d, JHH = 7.4 Hz, H ), 7,43 (d, JHH = 2.3 Hz, 1H, H ), 7.13 (m,
6
1
1
8
3
1H, H ′), 6.97 (m, 1H, H ), 6.78 (m, 2H, H ′, H ′), 6.61 (d, JHH = 7.7
2
3
4
8
[
Cp*IrCl ] (108 mg, 0.135 mmol, 0.55 equiv) in THF (4 mL),
Hz, 1H, H ′), 6.39 (dd, 1H, JHH = 6.3 Hz, JHH = 2.3 Hz, 1H, H ),
11 11 11 11
2
2
and the suspension was stirred overnight at room temperature. The
solvent was removed in vacuo, and the residue dissolved in toluene and
filtered over a pad of Celite. After drying in vacuo, the crude product
was washed with diethyl ether and n-pentane to give 2-Cl as an orange,
air-stable solid. Crystals suitable for an X-ray diffraction study were
obtained from slow diffusion of n-pentane in a solution of 2-Cl in
1.29 (s, 15H, Cp*), 1.00 (2, 9H, H /H ′), 0.99 (2, 9H, H /H ′).
3 1 7
1
C{ H} NMR (150.9 MHz, C D , 295 K): δ (ppm) = 163.2 (C ′),
6
6
5
5
5
5
4
4
7
160.5 (C /C ′), 160.2 (C /C ′), 160.1 (C ′), 158.5 (C ), 155.7 (C ),
9
9
3
3
1
152.7 (C ), 147.6 (C ′), 140.4 (C ′), 131.7 (C ), 129.0 (C ), 128.4
1
2
2
6
8
8
(C ′), 123.3 (C ′), 120.5 (C ), 118.9 (C ), 116.1 (C ), 114.8 (C ′),
6
10
10
10
10
112.6 (C ′), 85.4 (C(CH ) Cp*), 33.4 (C /C ′), 33.3 (C /C ′),
3
1
11
11
11
11
+
dichloromethane at 7 °C. Yield: 143 mg, 76%. H NMR (600.1 MHz,
29.2 (C /C ′), 28.9 (C /C ′), 8.3 (C(CH ) Cp*). HRMS (ESI ):
3
3
2
+
C D , 295 K): δ (ppm) = 8.23 (d, J = 7.6 Hz, 1H, H ), 7.10 (s, 1H,
m/z calcd for C H ClIrN ([M + H] ) 774.2909; found 774.2916.
6
6
HH
36 44
5
6
1
3
2
H ), 6.99 (m, 1H, H ), 6.85 (d, J = 7.5 Hz, 1H, H ′), 6.81 (m, 1H,
Anal. (%) Calcd for C H ClIrN : C 55.90, H 5.60, N 9.05. Found: C
55.51, H 5.65, N 8.58.
HH
36 43 5
1
6
11a
11b
11
H ′), 6.74 (s, 1H, H ′), 4.32 (m, 1H, H /H ), 3.05 (m, 2H, H ′),
1
1a
11b
9
9a
9b
Me
2
2
4
.99 (m, 1H, H /H ), 2.54 (m, 2H, H ′), 2.45 (m, 1H, H /H ),
[Cp*Ir(Xyl-BPI )]Cl (4[Cl]). Complex 4-Cl (30.0 mg, 30.4 μmol)
was dissolved in methanol (2 mL), and the solution was stirred at rt
for 30 min. By removal of the solvent under vacuum, the product
4[Cl] was isolated as a red, air-stable solid. Single crystals suitable for
X-ray structure analysis were obtained by cooling a saturated solution
of 4[Cl] in methanol to 7 °C. Yield: 27.6 mg, 92%. H NMR (399.9
MHz, CD OD, 295 K): δ (ppm) = 8.90 (d, J = 2.2 Hz, 2H, H ),
9a
9b
13
13
.17 (m, 1H, H /H ), 1.84 (s, 3H, H ′), 1.74 (s, 3H, H ), 1.79 (m,
10
10
13
1
H, H , H ′), 1.40 (s, 15H, Cp*). C{ H} NMR (150.9 MHz,
1
2
12
5
C D , 295 K): δ (ppm) = 166.1 (C ), 163.3 (C ′), 162.8 (C ′), 159.8
6
6
4
5
4
7
8
7
8
(
(
(
C ′), 157.4 (C ), 157.2 (C ), 144.8 (C /C ), 143.8 (C ′/C ′), 140.9
3 7 8 3 7 8 1
1
C ′), 133.3 (C /C ), 132.9 (C ), 129.7 (C ′/C ′), 129.5 (C ), 129.0
1
2
6
2
6
4
9
C ′), 124.4 (C ′), 122.3 (C ), 121.3 (C ), 114.4 (C ′), 86.2 (C(CH )
3
3
H
H
1
1
11
9
9
10
10
3
4
7
2
Cp*), 39.2 (C ), 34.7 (C ′), 29.2 (C ), 28.6 (C ′), 22.8 (C /C ′),
8.29 (dd, J = 8.4 Hz, J = 2.3 Hz, 2H, H ), 7.85 (s, 2H, H ), 7.63
HH HH
K
DOI: 10.1021/om501138t
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
d, 3JHH = 8.4 Hz, 2H, H ), 7.25 (s, 4H, H ), 7.15 (s, 2H, H ), 2.48
6
14
13
(ESI ): m/z calcd for C H IrN ([M − BPh ] ) 738.3148; found
+
+
(
(
(
1
(
9
36
43
5
4
15
14
13
1
−
−
s, 6H, H ), 2.35 (s, 12H, H ), 1.48 (s, 15H, Cp*). C{ H} NMR
100.6 MHz, CD OD, 295 K): δ (ppm) = 163.9 (C ), 156.8 (C ),
51.3 (C ), 143.6 (C ), 141.0 (C ), 140.6 (C ), 138.9 (C ), 136.9
C ), 136.3 (C ), 131.9 (C ), 126.0 (C ), 125.7 (C ), 124.8 (C ),
738.3155. HRMS (ESI ): m/z calcd for C H B ([BPh ] ) 319.1664;
found 319.1654. Anal. (%) Calcd for C H BIrN : C 68.16, H 6.01, N
60 63 5
6.62. Found: C 68.04, H 6.14, N 6.62.
[Cp*Ir(oMe-BPI)MeCN]BPh (1-MeCN[BPh ]). A mixture of 1-Cl
(80.0 mg, 0.116 mmol, 1.0 equiv) and NaBPh (43.7 mg, 0.128 mmol,
1.1 equiv) in 5 mL of acetonitrile was stirred for 4 h at room
temperature. The mixture was filtered through ALOX,; then the filtrate
was evaporated to dryness. The residue was dissolved in dichloro-
methane and filtered over a pad of Celite to remove excess NaBPh4.
24 20 4
4
5
3
9
1
7
12
10
3
8
13
6
11
2
4 4
14
15
0.2 (C(CH ) Cp*), 21.5 (C ), 20.6 (C ), 9.2 (C(CH ) Cp*).
3
3
4
+
+
HRMS (ESI ): m/z calcd for C H IrN ([M − Cl] ) 862.3461;
46
47
5
found 862.3459. Anal. (%) Calcd for C H ClIrN ·3CH OH: C
46
47
5
3
5
9.23, H 5.98, N 7.05. Found: C 59.04, H 5.54, N 7.54.
Cp*Ir(tBu-BPI)]Cl (5[Cl]). Complex 5-Cl (50.0 mg, 64.6 μmol) was
[
dissolved in methanol (2 mL), and the solution was stirred at room
temperature for 30 min. By removal of the solvent under vacuum, the
product 5[Cl] was isolated as a red, air-stable solid. Single crystals
suitable for X-ray structure analysis were obtained by cooling a
saturated solution of 5[Cl] in benzene to 7 °C. Yield: 46.4 mg, 94%.
Drying afforded the product 1-MeCN[BPh ] as an orange, air-stable
solid. Suitable crystals for an X-ray diffraction study of the
4
corresponding propionitrile complex 1-EtCN[BPh ] were obtained
4
by slow diffusion of n-pentane in a saturated solution of 1-
1
MeCN[BPh ] in propionitrile. Yield: 63.3 mg, 78%. H NMR
4
1
3
3
H NMR (399.9 MHz, CD Cl , 295 K): δ (ppm) = 9.68 (d, J = 6.2
(600.1 MHz, CD Cl , 295 K): δ (ppm) = 7.91 (d, J = 7.4 Hz, 1H,
2
2
HH
2
2
HH
9
2
1
3
2
7
7
1
Hz, 2H, H ), 7.93 (m, 2H, H ), 7.61 (m, 2H, H ), 7.49 (dd, J = 6.1
Hz, J = 2.3 Hz, 2H, H ), 7.45 (d, J = 2.3 Hz, 2H, H ), 1.47 (s,
5H, Cp*), 1.35 (s, 18H, H ). C{ H} NMR (100.6 MHz, CD Cl ,
95 K): δ (ppm) = 165.8 (C ), 161.3 (C ), 156.5 (C ), 155.4 (C ),
38.4 (C ), 131.9 (C ), 122.5 (C /C ), 122.4 (C /C ), 121.8 (C ),
8.7 (C(CH ) Cp*), 35.5 (C ), 30.4 (C ), 9.4 (C(CH ) Cp*).
HRMS (ESI ): m/z calcd for C H IrN ([M − Cl] ) 774.2909;
found 774.2916. Anal. (%) Calcd for C H ClIrN : C 55.90, H 5.60,
H ), 7.66 (m, 2H, H , H ′), 7.47 (m, 1H, H ), 7.31 (m, 8H, o-CH
HH
4
8
4
6
1 6 6 8
BPh
CH BPh
), 7.25 (m, 2H, H ′, H ), 7.03 (m, 2H, H ′, H ), 7.01 (m, 8H, m-
HH
HH
4
11
13
1
3
3
1
2
1
8
4
), 6.85 (t, JHH = 7.2 Hz, 4H, p-CH BPh
4
), 6.71 (d, JHH = 7.8
2
2
7
4
5
9
8
3
2
10
Hz, 1H, H ′), 6.44 (d, JHH = 7.7 Hz, 1H, H ′), 2.69 (s, 3H, H ), 2.48
3
1
2
8
2
8
6
10
13
1
(s, 3H, H ′), 2.38 (s, 3H, NCCH
), 1.51 (s, 15H, Cp*). C{ H}
3
10
11
1
NMR (150.9 MHz, CD Cl , 295 K): δ (ppm) = 164.5 (q, JBC = 49.3
3
3
2 2
+
+
5
5
4‘
9
Hz, ipso-CB BPh ), 161.6 (C /C ′), 160.6 (C ), 159.5 (C ), 159.1
4
9 4 7 7 3
36
43
5
5
5
(C /C ′), 158.8 (C ′), 157.8 (C ), 140.2 (C /C ′), 139.5 (C ), 138.6
36
43
5
7
7
3
1
N 9.05. Found: C 55.76, H 5.59, N 9.09.
Cp*Ir(tBu-BPI)]OTf (5[OTf]). Method A: To a solution of 5-Cl (60.0
(C /C ′), 136.2 (m, o-CH BPh ), 132.0 (C ′), 131.4 (C ), 131.0
1 3 2 6
4
[
(C ′), 126.0 (q, J = 2.7 Hz, m-CH BPh ), 124.9 (C ′), 123.3 (C ),
BC
4
2 8 2 8
mg, 77.6 μmol, 1.0 equiv) in dichloromethane (3 mL) was added
AgOTf (20.0 mg, 77.6 μmol, 1.0 equiv), and the reaction mixture was
stirred for 30 min in the dark. The solvent was removed in vacuo, and
the residue dissolved in toluene and filtered over a pad of Celite. After
drying in vacuo, the product 5[OTf] was precipitated in a mixture of
dichloromethane/n-pentane as a red, air-stable solid. Yield: 64.7 mg,
122.5 (C /C ), 122.4 (C /C ), 122.1 (p-CH BPh ), 121.5 (CN), 118.9
4
6
8
10
10
(C ′), 111.7 (C ′), 90.5 (C(CH ) Cp*), 29.3 (C ), 24.6 (C ′), 9.3
(C(CH ) Cp*), 3.7 (NCCH ). HRMS (ESI ): m/z calcd for
C H IrN ([M − MeCN − BPh ] ) 654.2209; found 654.2192.
HRMS (ESI ): m/z calcd for C H B ([BPh ] ) 319.1664; found
3
+
3
3
+
3
0
31
5
4
−
−
24
20
4
319.1660. Anal. (%) Calcd for C H BIrN : C 66.33, H 5.37, N 8.29.
56
54
5
9
4%. Method B: To a methanolic solution of 5[Cl] (60.0 mg, 0.078
Found: C 65.40, H 5.39, N 8.18. Due to cocrystallization with variable
amounts of solvent, correct elemental analyses could not be obtained
despite numerous attempts.
mmol, 1.0 equiv) was added AgOTf, and the reaction mixture was
stirred for 30 min in the dark. The solvent was removed in vacuo, and
the residue dissolved in toluene and filtered over a pad of Celite. After
drying in vacuo, the product 5[OTf] was obtained as a red, air-stable
solid. Yield: 66.1 mg, 96%. Crystals suitable for an X-ray diffraction
study were obtained by cooling a saturated solution of 5[OTf] in
[Cp*Ir(oMe-BPI′)] (1-BPI′). To a suspension of 1-Cl (96.5 mg,
0.140 mmol) in 4 mL of acetonitrile was added 0.1 mL of NaOH
solution (0.3 M), and the reaction mixture turned to an orange
solution and was stirred for 9 h. The solvent of the dark brown mixture
was removed in vacuo; then, the residue was dissolved in 8 mL of
toluene and washed with water (3 × 10 mL). Drying the organic phase
1
benzene to 7 °C. H NMR (399.9 MHz, C D , 295 K): δ (ppm) =
6
6
3
9
2
3
9
.78 (d, J = 6.2 Hz, 2H, H ), 7.98 (m, 2H, H ), 7.90 (dd, J = 6.2
HH HH
4
8
4
6
Hz, J = 2.1 Hz, 2H, H ), 7.56 (d, J = 2.1 Hz, 2H, H ), 7.05 (m,
over MgSO and subsequent evaporation of the solvent gave the
HH
HH
4
1
11
13
1
2
H, H ), 1.30 (s, 15H, Cp*), 1.03 (s, 18H, H ). C{ H} NMR
cyclometalated compound 1-BPI′ as a dark green, air-stable solid.
Single crystals suitable for an X-ray diffraction analysis were obtained
from slow diffusion of n-pentane into a saturated solution of 1-BPI′ in
7
4
5
(
100.6 MHz, C D , 295 K): δ (ppm) = 165.6 (C ), 160.5 (C /C ),
6 6
4
5
9
3
1
8
1
56.4 (C /C ), 155.6 (C ), 138.7 (C ), 131.3 (C ), 123.0 (C ), 122.1
2
6
10
11
1
(
C ), 121.5 (C ), 88.1 (C(CH ) Cp*), 34.9 (C ), 29.9 (C ), 8.7
C(CH ) Cp*). F{ H} NMR (376.3 MHz, C D , 295 K): δ (ppm) =
dichloromethane at 7 °C. H NMR (600.1 MHz, CD Cl , 295 K): δ
3
2
2
1
9
1
3
7
1
1
(
(ppm) = 8.24 (d, J = 7.5 Hz, 1H, H ′), 7.97 (m, 1H, H /H ′), 7.77
3
6
6
HH
+
+
1 1 2 2 3
−
77.26 (s, CF ). MS (ESI ): m/z (%) = 738.3 (100) [M − OTf] . MS
(m, 1H, H /H ′), 7.50 (m, 2H, H , H ′), 7.43 (t, J = 7.6 Hz, 1H,
3
HH
−
−
+
7 6 8 3 8
(
ESI ): m/z (%) = 149.1 (100) [OTf] . HRMS (ESI ): m/z calcd for
H ), 7.91 (m, 2H, H , H ), 6.73 (d, J = 7.5 Hz, 1H, H ′), 2.79 (s,
HH
+
10 10 13 1
C H IrN ([M − OTf] ) 738.3142; found 738.3154. Anal. (%)
Calcd for C H F IrN O S·0.5CH Cl : C 48.96, H 5.02, N 7.41.
Found: C 48.90, H 4.96, N 6.98.
Cp*Ir(tBu-BPI)]BPh4 (5[BPh ]). Sodium tetraphenylborate (44.1
3H, H ), 2.48 (s, 3H, H ′), 1.31 (s, 15H, Cp*). C{ H} NMR
3
6
43
5
4 4 9
48
61
3
5
3
2
2
(150.9 MHz, CD Cl , 295 K): δ (ppm) = 164.0 (C /C ′), 161.7 (C ),
5 5 4 4 9 7
2
2
161.0 (C ), 159.8 (C ′), 155.6 (C /C ′), 152.6 (C ′), 150.9 (C ′),
3 3 7 3 3 2 2
[
139.9 (C /C ′), 139.0 (C ), 138.4 (C /C ′), 130.74 (C /C ′), 129.7
2 2 8 6 1 1 1 1
4
mg, 0.129 mmol, 1.0 equiv) was added to a solution of 5[Cl] (100 mg,
.129 mmol, 1.0 equiv) in 4 mL of methanol and stirred for 15 min at
room temperature. The precipitate was filtered off, washed with water
3 × 1 mL) and methanol (2 × 1 mL), and dried in vacuo to yield
[BPh ] as a red powder. Crystals suitable for an X-ray diffraction
(C /C ′), 122.6 (C ), 122.4 (C ′), 121.6 (C /C ′), 121.0 (C /C ′),
6 8 10 10
0
120.6 (C ), 120.3 (C ′), 88.5 (C(CH ) Cp*), 30.7 (C ), 23.4 (C ′),
+ +
3
9.2 (C(CH ) Cp*). HRMS (FAB ): m/z calcd for C H IrN ([M] )
3
30 30
5
(
653.2130; found 653.2157. Anal. (%) Calcd for C H IrN : C 55.20,
30 30 5
5
H 4.63, N 10.73. Found: C 55.33, H 4.85, N 10.65.
4
study were obtained by slow diffusion of n-pentane in a saturated
[Cp*Ir(oMe-BPI)I] (1-I). To a solution of 50.0 mg of 1-Cl (58.0
μmol, 1.0 equiv) in 8 mL of acetone was added a solution of 20.8 mg
of NaI (139 μmol, 2.5 equiv) in 2 mL of acetone. After stirring for 1 h
the solvent was removed under reduced pressure and the crude
product was dissolved in toluene. The solution was filtered through a
pad of Celite, and the filtrate was evaporated to dryness to give 1-I as
an orange solid. Single crystals suitable for an X-ray diffraction study
were obtained by slow diffusion on n-pentane into a solution of 1-I in
1
solution of 5[BPh ] in dichloromethane. Yield: 120 mg, 88%. H
NMR (600.1 MHz, CD Cl , 295 K): δ (ppm) = 8.25 (d, J = 6.1
Hz, 2H, H ), 7.86 (m, 2H, H ), 7.58 (m, 2H, H ), 7.45 (d, J = 2.3
Hz, 2H, H ), 7.23 (m, 8H, o-CH BPh ), 7.17 (dd, J = 6.1 Hz, J
=
4
4
3
2
2
HH
9
2
1
4
HH
6
3
4
4
HH
HH
8
3
2.3 Hz, 2H, H ), 6.93 (m, 8H, m-CH BPh ), 6.78 (t, J = 7.2 Hz,
H, p-CH BPh ), 1.28 (s, 18H, H ), 1.26 (s, 15H, Cp*). C{ H}
4
7
4 HH
11
13
1
NMR (150.9 MHz, CD Cl , 295 K): δ (ppm) = 166.2 (C ), 163.9 (m,
2
2
4
5
9
3
1
ipso-CB), 161.3 (C ), 156.7 (C ), 151.0 (C ), 137.6 (C ), 135.9 (q,
dichloromethane. Yield: 43.9 mg, 97%. H NMR (600.1 MHz, C D ,
6
6
3
1
2
3
2
6
JCB = 1.4 Hz, o-CH BPh ), 131.9 (C ), 125.6 (q, J = 2.8 Hz, m-CH
295 K): δ (ppm) = 8.08 (d, J = 7.4 Hz, 1H, H ), 7.10 (m, 2H, H ,
4
CB
HH
6
2
8
7
6
1
7
BPh ), 122.6 (C ), 122.3 (C ), 121.7 (p-CH BPh ), 121.4 (C ), 88.4
H ′), 7.05 (m, 1H, H ′), 6.92 (m, 1H, H ), 6.77 (m, 1H, H ), 6.74 (m,
4
4
1
0
11
1 3 2 3
(C(CH ) Cp*), 35.2 (C ), 29.9 (C ), 8.8 (C(CH ) Cp*). HRMS
1H, H ′), 6.64 (d, J = 7.6 Hz, 1H, H ′), 6.56 (d, J = 7.2 Hz, 1H,
3
3
HH
HH
L
DOI: 10.1021/om501138t
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
8
3
8
10
10
10
13
1
H ′), 6.15 (d, J = 7.2 Hz, 1H, H ), 2.98 (s, 3H, H ), 2.47 (s, 3H,
3H, H ′), 2.18 (s, 3H, H ), 2.08 (s, 15H, Cp*). C{ H} NMR
HH
1
0
13
1
5 4
H ′), 1.36 (s, 15H, Cp*). C{ H} NMR (150.9 MHz, C D , 295 K):
(150.9 MHz, C D , 295 K): δ (ppm) = 162.6 (C ′), 159.7 (C ′), 158.0
9 5 9 4 7 7
6
6
6
6
5
9
4
5
δ (ppm) = 162.7 (C ′), 161.4 (C ), 159.8 (C ′), 159.5 (C ), 157.0
(C ′), 156.4 (C ), 155.8 (C ), 155.4 (C ), 137.7 (C ), 137.4 (C ′),
9
4
3
7
7
3
3 3 1 2 1
(
1
(
(
(
C ′), 156.2 (C ), 140.4 (C ′), 137.4 (C ′), 137.0 (C ), 132.1 (C ),
133.4 (C ), 130.5 (C ′), 130.3 (C ), 126.3 (C ′), 125.9 (C ′), 121.7
8 2 8 6 6 6
1
1
2
6
2
29.8 (C ), 129.1 (C ′), 124.1 (C ′), 121.7 (C ), 121.5 (C ), 119.8
(C ), 121.1 (C ), 177.7 (C ′), 177.1 (C ), 177.1 (C ), 111.2 (C ′),
8
8
6
10
10 10
C ), 117.2 (C ′), 113.4 (C ′), 87.4 (C(CH ) Cp*), 34.5 (C ), 24.5
87.2 (C(CH ) Cp*), 24.3 (C ′), 23.2 (C ), 10.3 (C(CH ) Cp*). MS
+ +
3
3
3
1
0
+
C ′), 9.4 (C(CH ) Cp*). HRMS (FAB ): m/z calcd for C H IIrN
(LIFDI ): m/z calcd for C H IrN ([M] ) 668.22; found 668.23.
3
30 32
5
30 31 6
+
[M + H] ) 782.1326; found 782.1304. Anal. (%) Calcd for
Anal. (%) Calcd for C H IrN : C 53.95, H 4.68, N 12.58. Found: C
30 31 6
C H IIrN ·CH Cl : C 43.01, H 3.84, N 8.19. Found: C 43.50, H
53.34, H 5.10, N 12.69.
[Cp*Ir(oF-BPI)]Cl (3[Cl]). The κ -(N,N)-coordinated complex 3-Cl
(8.0 mg, 11.8 μmol) was dissolved in methanol-d (0.5 mL) and stirred
3
0
31
5
2
2
2
3
.91, N 7.89.
Cp*Ir(oMe-BPI)PPh ]PF (1-PPh [PF ]). A mixture of 1-Cl (50.0
[
3
6
3
6
4
mg, 72.5 μmol, 1.0 equiv), PPh (27.9 mg, 79.8 μmol, 1.1 equiv), and
at room temperature for 15 min. Within this time, an equilibrium
3
2
3
TlPF (20.9 mg, 79.8 μmol, 1.1 equiv) in 5 mL of THF was stirred for
between the κ -(N,N) and κ -(N,N,N) species 3-Cl and 3[Cl] has
appeared with a ratio of 0.47:1 (3-Cl:3[Cl]). Compound 3[Cl] could
not be isolated, and the NMR data were determined from the mixture
6
1
h at room temperature. The crude product was dissolved in toluene
and filtered through a pad of Celite. The filtrate was dried, and the
residue was washed with diethyl ether (3 × 2 mL). Drying in vacuo
afforded the product 1-PPh [PF ] as an orange, air-stable solid. Single
1
19
of 3-Cl and 3[Cl]. H{ F} NMR (399.9 MHz, CD OD, 295 K): δ
3
7
2
1
(ppm) = 8.17 (m, 2H, H ), 7.99 (m, 2H, H ), 7.73 (m, 2H, H ), 7.48
3
6
3
8
3
6
crystals suitable for X-ray structure analysis were obtained by slow
evaporation of a concentrated benzene solution at 7 °C. Yield: 47.7
(d, J = 7.9 Hz, 2H, H ), 7.35 (d, J = 8.0 Hz, 2H, H ), 1.37 (s,
HH HH
13
1
15H, Cp*).1 C{ H} NMR (150.9 MHz, CD OD, 295 K): δ (ppm) =
9 4 5
3
1
mg, 62%. H NMR (399.9 MHz, CD Cl , 295 K): δ (ppm) = 7.73 (m,
163.21 (d, JCF = 239.1 Hz, C ), 162.2 (C ), 155.5 (C ), 145.3 (m,
2
2
7
7
7
3
1
2
8
6
6
H, o-CH PPh ), 7.66 (m, 2H, H , H ′), 7.34 (m, 9H, m-CH, p-CH
C ), 139.7 (C ), 132.3 (C ), 122.3 (C ), 121.5 (C ), 108.4 (m, C ),
3
1
1
2
2
6
6
19
1
PPh ), 7.24 (m, 2H, H /H ′, H /H ′), 7.12 (m, 1H, H /H ′), 7.06 (m,
89.1 (C(CH
, 295 K): δ (ppm) = −52.23 (s, 2F).
[Cp*Ir(oF-BPI)]BPh (3[BPh ]). Sodium tetraphenylborate (24.6 mg,
) Cp*), 8.0 (C(CH ) Cp*). F{ H} NMR (396.3 MHz,
3 3
3
1
1
6
6
8
8
3
2
H, H /H ′, H /H ′), 6.85 (m, 2H, H , H ′), 6.46 (d, J = 7.8 Hz,
C D
6 6
HH
2
2
10
10
10
10
1
H, H /H ′), 2.65 (s, 3H, H /H ′), 2.56 (s, 3H, H /H ′), 1.66 (d,
4
4
5
13
1
J
= 1.8 Hz, 15H, Cp*). C{ H} NMR (150.9 MHz, CD Cl , 295
0.072 mmol, 1.0 equiv) was added to a suspension of 3-Cl/3[Cl] (50.0
mg, 0.072 mmol, 1.0 equiv) in 3 mL of methanol and stirred for 30
min at room temperature. The precipitate was filtered off, washed with
water (3 × 1 mL) and methanol (2 × 1 mL), and dried in vacuo to
HP
2
2
4
5
5
9
9
K): δ (ppm) = 174.7 (C ), 160.5 (C /C ′), 158.5 (C /C ′), 158.1
9
9
4
5
5
7
7
7
(
C /C ′), 155.7 (C ′), 152.4 (C /C ′), 138.6 (C /C ′), 138.2 (C /
7 3 3 2
C ′), 135.4 (C /C ′), 134.7 (d, J = 10.8 Hz, o-CH PPh ), 133.1
CP
3
3
3
1
1
1
1
(
(
1
(
(
(
(
9
C /C ′), 131.4 (p-CH PPh ), 131.3 (C /C ′), 130.2 (C /C ′), 128.4
yield 3[BPh
diffraction study were obtained by slow diffusion of n-pentane in a
saturated solution of 3[BPh ] in dichloromethane. Yield: 65.6 mg,
93%. H NMR (600.1 MHz, CD Cl , 295 K): δ (ppm) = 7.90 (m, 2H,
H ), 7.83 (m, 2H, H ), 7.61 (m, 2H, H ), 7.30 (d, JHH = 7.9 Hz, 2H,
] as a red powder. Crystals suitable for an X-ray
4
3
3
2
2
2
2
d, J = 10.7 Hz, m-CH PPh ), 125.6 (C /C ′), 124.1 (C /C ′),
CP
3
6
6
6
6
8
8
8
8
20.1 (C /C ′), 118.9 (C /C ′), 113.3 (C /C ′), 112.2 (C /C ′), 93.9
4
2
10
10
10
10
1
d, J = 2.3 Hz, C(CH ) Cp*), 24.2 (C /C ′), 23.9 (C /C ′), 9.5
2
2
CP
3
31
1
2
7
1
3
C(CH ) Cp*) ppm. P{ H} NMR (161.9 MHz, CD Cl , 295 K): δ
3
2
2
1
6
3
8
ppm) = 17.9 (s), −144.5 (sept, JPF = 709.1 Hz, PF ). HRMS
H ), 7.22 (m, 8H, o-CH), 6.98 (d, JHH = 8.0 Hz, 2H, H ), 6.92 (m,
6
+
+
3
11
FAB ): m/z calcd for C H IrN P ([M − PF ] ) 916.3120; found
8H, m-CH), 6.77 (t, JHH = 7.2 Hz, 4H, p-CH), 1.23 (s, 15H, H ).
48
46
5
6
1
3
1
16.3125. Due to cocrystallization with variable amounts of solvent,
C{ H} NMR (150.9 MHz, CD
Cl , 295 K): δ (ppm) = 164.0 (q,
2 2
1JCB = 49.5 Hz, ipso-CB), 163.1 (d, JCF = 255.9 Hz, C ), 162.0 (C ),
155.8 (C ), 144.8 (m, C ), 137.9 (C ), 135.9 (m, o-CH, BPh ), 132.4
(C ), 125.6 (q, J = 2.8 Hz, m-CH, BPh ), 122.7 (C ), 121.9 (C ),
1
9
4
correct elemental analyses could not be obtained despite numerous
attempts.
5
7
3
4
1
3
2
6
[
Cp*Ir(oMe-BPI)(N )] (1-N ). To a suspension of 1-Cl (100 mg,
3
3
CB 4
8
0
.145 mmol, 1.0 equiv) in methanol (4 mL) was added NaN (9.43
121.7 (p-CH, BPh ), 108.2 (m, C ), 89.0 (C(CH ) Cp*), 9.1 (C(CH )
4 3 3
19 1
3
mg, 0.145 mmol, 1.0 equiv), and the mixture was stirred for 2 h at
room temperature. Then, the reaction mixture was evaporated to
dryness, and the residue was dissolved in toluene and filtered over a
pad of Celite. The solvent was removed in vacuo to yield the azido
Cp*). F{ H} NMR (376.3 MHz, CD Cl , 295 K): δ (ppm) =
2 2
+
−51.58 (s, 2F). HRMS (ESI ): m/z calcd for C H F IrN ([M −
28
25
2
5
+
−
BPh ] ) 662.1707; found 662.1705. HRMS (ESI ): m/z calcd for
4
−
C H B ([BPh ] ) 319.1664; found 319.1634. Anal. (%) Calcd for
24
20
4
complex 1-N as an orange, air-stable solid. Single crystals suitable for
C H BF IrN : C 63.67, H 4.62, N 7.14. Found: 62.82, H 4.73, N
52 45 2 5
3
X-ray diffraction were obtained by slow diffusion of n-pentane in a
7.22. Due to cocrystallization with variable amounts of solvent,
improved elemental analyses could not be obtained despite numerous
attempts.
1
solution of 1-N in dichloromethane. Yield: 89.8 mg, 89%. H NMR
3
3
(
600.1 MHz, C D , 295 K): δ (ppm) = 8.09 (d, J = 7.7 Hz, 1H,
6
6
HH
2
3
6
6
7
H ), 7.29 (d, J = 7.9 Hz, 1H, H ′), 7.12 (m, 2H, H , H ′), 6.93 (m,
[Cp*Ir(oF-BPI)(N )] (3-N ). To a suspension of 3-Cl/3[Cl] (30.0
HH
3
3
1
7
1
3
1
1
H, H ), 6.82 (m, 1H, H ), 6.75 (m, 1H, H ′), 6.68 (d, J = 7.5 Hz,
mg, 0.043 mmol, 1.0 equiv) in methanol (1.5 mL) was added NaN3
(2.80 mg, 0.043 mmol, 1.0 equiv), and the mixture was stirred for 2 h
at room temperature. The precipitate was filtered off, dissolved in
benzene, and filtered over a pad of Celite. The solvent of the filtrate
was removed in vacuo, and the crude product was washed with n-
HH
2
3
8
3
H, H ′), 6.57 (d, J = 7.5 Hz, 1H, H ′), 6.14 (d, J = 7.2 Hz, 1H,
HH
10
HH
8
10
13
1
H ), 2.71 (s, 3H, H ), 2.48 (s, 3H, C ′), 1.26 (s, 15H, Cp*). C{ H}
9
5
NMR (150.9 MHz, C D , 295 K): δ (ppm) = 162.1 (C ′), 159.7 (C ),
6
6
4
9
4
5
3
1
(
1
(
ν
(
59.1 (C ′), 158.9 (C ), 157.1 (C ), 155.9 (C ′), 139.7 (C ), 136.7
7 7 3 1 1 2
C ′), 136.4 (C ), 131.7 (C ′), 129.0 (C ), 128.6 (C ′), 123.7 (C ′),
pentane to yield 3-N as an orange, air-stable solid. Single crystals
3
2
6
8
8
6
20.8 (C ), 120.6 (C ′), 119.1 (C ), 116.6 (C ′), 113.2 (C ′), 85.1
suitable for X-ray diffraction were obtained by slow diffusion of n-
1
0
10
C(CH ) Cp*), 26.6 (C ), 23.6 (C ′), 7.7 (C(CH ) Cp*). IR (KBr):
pentane in a concentrated solution of 1-N in dichloromethane at 7
3
3
3
−
1
+
1
̃
(cm ) = 2034 (s, N ). HRMS (FAB ): m/z calcd for C H IrN
°C. Yield: 23.0 mg, 76%. H NMR (399.9 MHz, CD Cl , 295 K): δ
3
30 31
8
2
2
+
3
2
7
7
[M] ) 696.2301; found 696.2296. Anal. (%) Calcd for C H IrN : C
(ppm) = 7.88 (d, J = 7.4 Hz, 1H, H ), 7.79 (m, 2H, H , H ′), 7.44
30
31
8
HH
1 1 3 6
5
1.78, H 4.49, N 16.10. Found: 52.00, H 4.57, N 15.34.
Cp*Ir(oMe-BPI)(N)] (1-N). An orange suspension of 1-N (50.0 mg,
(m, 1H, H ), 7.25 (m, 1H, H ′), 7.16 (d, J = 7.7 Hz, 1H, H ′), 7.98
HH
3 5 6 8 8
[
(dd, J = 7.7 Hz, J = 2.0 Hz, 1H, H ), 6.71 (m, 2H, H , H ′), 6.58
3
HH
HF
3 2 13 1
7
1.9 μmol) in 2 mL of toluene was photolyzed with a Hg lamp at
(d, J = 7.7 Hz, 1H, H ′), 1.59 (s, 15H, Cp*). C{ H} NMR (100.6
HH
1 9 9
room temperature for 2 d, whereupon the reaction mixture turned into
a green solution. The solvent was removed in vacuo to yield compound
MHz, CD Cl , 295 K): δ (ppm) = 163.5 (d, J = 238.5 Hz, H /H ′),
2
2
CF
1 9 9 5 5 4
163.0 (d, J = 253.8 Hz, H /H ′), 161.7 (C /C ′), 161.5 (C ′),
CF
4 5 5 3 7 7
1
-N as a dark green solid. Single crystals were obtained from slow
159.7 (C ), 156.6 (C /C ′), 142.6 (d, J = 8.3 Hz, H /H ′), 142.3
CF
3 7 7 3 3 1
diffusion of n-pentane into a saturated solution of 1-N in toluene.
Yield: 47.0 mg, 98%. H NMR (600.1 MHz, C D , 295 K): δ (ppm) =
(d, J = 10.4 Hz, H /H ′), 140.8 (C ), 131.7 (C ′), 131.2 (C ),
CF
1
1 2 2 4 6
130.4 (C ′), 124.6 (C ′), 122.0 (C ), 120.6 (d, J = 3.2 Hz, H ′),
6
6
CF
3
6
3
2
4 6 2 8 8
7
.90 (d, J = 8.0 Hz, 1H, H ), 7.31 (d, J = 7.9 Hz, 1H, H ), 7.19
113.6 (d, J = 4.9 Hz, H ), 104.2 (d, J = 31.5 Hz, H /H ′), 103.1
HH
HH
CF
CF
7
7
3
6
2 8 8
(
(
m, 1H, H ′), 7.08 (m, 2H, H ), 6.76 (d, J = 7.9 Hz, 1H, H ′), 6.71
(d, J = 36.8 Hz, H /H ′), 87.4 (C(CH ) Cp*), 9.3 (C(CH ) Cp*).
HH
CF
3
3
1
2
8
1
8
19 1
m, 1H, H ), 6.64 (m, 2H, H ′, H ′), 6.47 (m, 2H, H ′, H ), 2.46 (s,
F{ H} NMR (376.3 MHz, CD Cl , 295 K): δ (ppm) = −57.36 (s,
2
2
M
DOI: 10.1021/om501138t
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
−
1
15
14
10
17
11
18
F), −69.65 (s, F′). IR (KBr): ν
̃
(cm ) = 2034 (s, N ). HRMS
(C ), 76.1 (C ), 34.7 (C ), 30.9 (C ), 29.0 (C ), 21.2 (C ), 16.7
3
+
+
12
+
+
(
FAB ): m/z calcd for C H F IrN ([M] ) 704.1799; found
(C ). HRMS (ESI ): m/z calcd for C H N Os ([M − Cl] )
2
8
25
2
8
36 42
5
−
−
7
04.1814. HRMS (ESI ): m/z calcd for C H B ([BPh ] )
736.3055; found 736.3050. Anal. (%) Calcd for C H ClN Os: C
2
4
20
4
36 42 5
3
19.1664; found 319.1634. Due to cocrystallization with variable
56.12, H 5.49, N 9.09. Found: C 55.29, H 5.49, N 8.53. Due to
cocrystallization with variable amounts of solvent, improved elemental
analyses could not be obtained despite numerous attempts.
amounts of solvent, correct elemental analyses could not be obtained
despite numerous attempts.
[(p-Cym)Os(oF-BPI)Cl] (6-Cl). A solution of LDA (30.5 mg, 0.285
[(p-Cym)Os(tBu-BPI)]BPh4 (7[BPh ]). Sodium tetraphenylborate
4
mmol, 1.5 equiv) in THF (2 mL) was added dropwise to a solution of
oF-BPIH (3) (63.6 mg, 0.190 mmol, 1.0 equiv) in THF (4 mL) at −78
(8.88 mg, 0.026 mmol, 1.0 equiv) was added to a solution of 7[Cl]
(20.0 mg, 0.026 mmol, 1.0 equiv) in 2.5 mL of methanol, and the
mixture was stirred for 30 min at room temperature. The precipitate
was filtered off, washed with water (3 × 1 mL) and methanol (2 × 1
°
C. After the addition was completed the solution was warmed to
room temperature and stirred for another 30 min. Then the reaction
mixture was added dropwise via cannula to a suspension of [(p-
Cym)OsCl ] (75.0 mg, 0.095 mmol, 0.55 equiv) in THF (4 mL), and
mL), and dried in vacuo to yield 7[BPh ] as a dark purple powder.
4
2
2
Crystals suitable for an X-ray diffraction study were obtained by slow
the suspension was stirred overnight at room temperature. The solvent
was removed in vacuo, and the residue dissolved in toluene and filtered
over a pad of Celite. After drying in vacuo, the crude product was
washed with diethyl ether (3 × 3 mL) and n-pentane (3 × 3 mL) to
4
1
1
give 6-Cl as a dark red solid. Yield: 88.2 mg, 67%. H NMR (600.1
3
2
MHz, C D , 295 K): δ (ppm) = 8.06 (d, J = 7.5 Hz, 1H, H ), 6.94
6
6
HH
1
7
6
1
7
2
6
(
6
1
(
2
=
m, 3H, H , H ′, H ′), 6.70 (m, 2H, H ′, H ), 6.58 (m, 2H, H ′, H ),
3
4
8
3
.2 (dd, J = 7.8 Hz, J = 2.5 Hz, 1H, H ′), 5.92 (d, J = 5.4 Hz,
HH
HH
HH
H, H1 ), 5.89 (m, 1H, H ), 5.84 (d, J = 5.4 Hz, 1H, H ), 5.42
2b
8
3
13b
HH
m, 1H, H1 ), 5.29 (d, J = 5.5 Hz, 1H, H ), 2.19 (m, 1H, H ),
3a
3
12a
15
HH
10
3
16a
16b
3
.13 (s, 3H, H ), 0.84 (d, J = 6.8 Hz, 3H, H /H ), 0.80 (d, J
HH
16b 13
HH
6.8 Hz, 3H, H1 /H ). C{ H} NMR (150.9 MHz, C D , 295 K):
6a
1
6
6
1
9
9
1
δ (ppm) = 163.2 (d, J = 400.5 Hz, C /C ′), 163.1 (d, J = 400.5
CF
4‘
CF
9
9
5
4
5
Hz, C /C ′), 163.5 (C ), 162.9 (C ′), 158.2 (C ), 156.0 (C ), 141.8
3
7
3
7
3
1
(
1
1
(
2
d, J = 7.8 Hz, C ′), 140.4 (m, C , C ), 131.5 (C ′), 130.4 (C ),
CF
1
2
2
4
6
29.7 (C ′), 124.0 (C ′), 122.6 (C ), 120.0 (d, J = 3.4 Hz, C ′),
CF
4
6
8
8
14
12.7 (d, J = 4.5 Hz, C ), 102.2 (m, H , H ′), 94.2 (C ), 92.1
CF
1
1
13a
13b
12a
12b
15
C ), 76.1 (C ), 75.6 (C ), 73.7 (C ), 73.4 (C ), 31.2 (C ),
2.4 (C1 /C ), 22.0 (C16a/C ), 18.4 (C ). F{ H} NMR (376.3
6a
16b
16b
10 19
1
MHz, C D , 295 K): δ (ppm) = −47.97 (s, F), −68.25 (s, F′). HRMS
6
6
+
+
(
DART ): m/z calcd for C H ClF N Os ([M + H] ) 696.1381;
28 25 2 5
found 696.1372. Anal. (%) Calcd for C H ClF N Os: C 48.44, H
28
24
2
5
3
.48, N 10.09. Found: C 49.17, H 3.96, N 9.03.
(p-Cym)Os(tBu-BPI)Cl] (7-Cl). The synthetic procedure of this
compound was the same as that of 6-Cl, using tBu-BPIH (5) (165 mg,
[
0
2
.400 mmol) instead of oF-BPIH to give 7-Cl as dark red solid. Yield:
1
13 mg, 69%. H NMR (600.1 MHz, THF-d , 295 K): δ (ppm) = 8.67
8
3
9
3
9‘
(
d, J = 6.4 Hz, 1H, H ), 8.24 (d, J = 5.3 Hz, 1H, H ), 7.77 (d,
HH HH
3
2
1
1
6
8
JHH = 7.5 Hz, 1H, H ), 7.28 (m, 1H, H ), 7.05 (m, 3H, H ′, H , H ′),
6
6
‘
3
8
3
.95 (s, 1H, H ), 6.76 (d, J = 6.3 Hz, 1H, H ), 6.20 (d, J = 7.7
HH HH
2
3
14b
3
Hz, 1H, H ′), 6.11 (d, J = 5.2 Hz, 1H, H ), 5.85 (d, J = 5.3
HH
HH
15b
3
15a
3
Hz, 1H, H ), 5.66 (d, J = 5.2 Hz, 1H, H ), 5.62 (d, J = 5.3
HH
HH
Hz, 1H, H1 ), 2.45 (m, 1H, H ), 2.23 (s, 3H, H ), 1.31 (s, 9H, H ),
4a
17
12
11
11
3
18a
18b
1
J
.29 (s, 9H, H ′), 1.09 (d, J = 6.9 Hz, 3H, H /H ), 1.04 (d,
HH
18a 18b 13 1
3
= 6.9 Hz, 3H, H /H ). C{ H} NMR (150.9 MHz, THF-d ,
8
HH
5
4
7
7
2
95 K): δ (ppm) = 164.3 (C ′), 164.0 (C ′), 162.2 (C ), 161.8 (C ′),
4 9 5 9 3 3
1
58.2 (C ), 157.9 (C ), 156.5 (C ), 149.2 (C ′), 141.3 (C /C ′), 132.3
3
3
1
1
2
2
(
(
(
C /C ′), 130.3 (C ), 129.6 (C ′), 124.5 (C ′), 121.6 (C ), 120.6
6 8 8 6 16 13
C ), 116.9 (C ), 116.1 (C ′), 113.1 (C ′), 94.2 (C ), 93.6 (C ), 77.2
1
4b
14a
15a
14a
15a
15b
10
C
), 76.3 (C /C ), 76.2 (C /C ), 73.7 (C ), 35.2 (C ′),
10 17 11 11 18a 18a
3
C
5.0 (C ), 32.1 (C ), 30.3 (C /C ′), 22.9 (C /C18b), 22.8 (C
/
1
8b
+
12
+
), 18.6 (C ). HRMS (DART ): m/z calcd for C H N Os ([M +
36
43
5
H] ) 772.2822; found 772.2803. Anal. (%) Calcd for C H ClN Os:
36
42
5
C 56.12, H 5.49, N 9.08. Found: C 55.45, H 5.40, N 8.68.
(p-Cym)Os(tBu-BPI)]Cl (7[Cl]). Complex 7-Cl (40.0 mg, 51.9
[
μmol) was dissolved in methanol (2 mL), and the solution was stirred
for 60 min at room temperature, whereupon the color changed from
red to purple. By removal of the solvent under vacuum, the product
7
9
=
[Cl] was isolated as a dark purple, air-stable solid. Yield: 36.8 mg,
1
3
1%. H NMR (600.1 MHz, CD OD, 295 K): δ (ppm) = 8.98 (d, J
3
HH
9
2
1
5.8 Hz, 2H, H ), 7.88 (m, 2H, H ), 7.56 (m, 2H, H ), 7.39 (s, 2H,
6
3
8
3
15
H ), 7.36 (d, J = 5.6 Hz, 2H, H ), 6.12 (d, J = 4.6 Hz, 2H, H ),
HH
HH
3
14
3
17
5
1
.96 (d, J = 4.6 Hz, 2H, H ), 1.96 (sept, J = 6.7 Hz, 1H, H ),
HH HH
12
11
3
18
.63 (s, 3H, H ), 1.29 (s, 18H, H ), 0.93 (d, J = 6.8 Hz, 6H, H ).
HH
1
3
1
7
C{ H} NMR (150.9 MHz, CD OD, 295 K): δ (ppm) = 165.9 (C ),
3
4
5
9
3
1
1
63.1 (C ), 157.0 (C ), 154.2 (C ), 136.2 (C ), 131.6 (C ), 122.0
2
6
8
6
8
16
13
(
C ), 121.0 (C /C ), 120.6 (C /C ), 96.8 (C ), 92.9 (C ), 76.5
N
DOI: 10.1021/om501138t
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Kα radiation, sealed tube, graphite monochromator: complexes 3-Cl,
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ASSOCIATED CONTENT
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*
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Supporting Information
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̈
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Corresponding Author
E-mail: lutz.gade@uni-hd.de. Fax: (+49) 6221-545609. Tel:
+49) 6221-548443.
*
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Notes
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(
ACKNOWLEDGMENTS
■
2
A.L.M. thanks Florian Mulks for help with the complex
syntheses. T.B. thanks the Fonds der Chemischen Industrie for
(
́
the doctoral Kekule fellowship and the Studienstiftung des
Deutschen Volkes for a doctoral fellowship. T.R. gratefully
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DOI: 10.1021/om501138t
Organometallics XXXX, XXX, XXX−XXX

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