Aryl carbon-chlorine (Ar-Cl) and aryl carbon-fluorine (Ar-F) bond cleavages by rhodium porphyrins

Article abstract of DOI:10.1016/j.jorganchem.2015.05.039

Aryl carbon-chlorine (Ar-Cl) bond cleavage has been achieved with rhodium(III) tetrakis-4-tolylporphyrin chloride (Rh(ttp)Cl) to give Rh(ttp)Ar. For 4-chlorofluorobenzene, the aryl carbon-fluorine (Ar-F) bond cleavage competes with the Ar-Cl bond cleavage. Mechanistic investigations show that the Ar-Cl bond cleavage goes through metalloradical ipso-substitution mechanism, while the Ar-F bond cleavage goes through nucleophilic aromatic substitution. The selectivity of the Ar-F or Ar-Cl bond cleavage can be controlled by tuning the temperature and substrate concentration.

Full text of DOI:10.1016/j.jorganchem.2015.05.039

Journal of Organometallic Chemistry 791 (2015) 82e89
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Aryl carbonechlorine (AreCl) and aryl carbonefluorine (AreF) bond
cleavages by rhodium porphyrins
Ying Ying Qian, Man Ho Lee, Wu Yang, Kin Shing Chan*
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Aryl carbonechlorine (AreCl) bond cleavage has been achieved with rhodium(III) tetrakis-4-
tolylporphyrin chloride (Rh(ttp)Cl) to give Rh(ttp)Ar. For 4-chlorofluorobenzene, the aryl carbon
efluorine (AreF) bond cleavage competes with the AreCl bond cleavage. Mechanistic investigations
show that the AreCl bond cleavage goes through metalloradical ipso-substitution mechanism, while the
AreF bond cleavage goes through nucleophilic aromatic substitution. The selectivity of the AreF or AreCl
bond cleavage can be controlled by tuning the temperature and substrate concentration.
© 2015 Elsevier B.V. All rights reserved.
Received 7 February 2015
Received in revised form
6 May 2015
Accepted 23 May 2015
Available online 27 May 2015
Keywords:
Rhodium porphyrin
Carbonechlorine bond activation
Carbonefluorine bond activation
1. Introduction
mechanism. IrII(ttp) (ttp ¼ tetrakis-4-tolylporphyrinato dianion)
radical, which is generated from reduction of Ir(ttp) (CO)Cl by KOH,
Ar-X bond cleavage is important in organic synthesis, especially
forarylearyl bondformation[1]. Sincearylchloridesaremorereadily
available and less expensive starting materials than aryl bromides
and iodides, the investigation of arylechlorine bond (AreCl) is
important [2]. Moreover, chlorinated dioxins and polychlorinated
biphenyls are toxic chemical waste [3]. The hydrodechlorination is
thus important in waste treatment. The mechanism of enzymatic
dehalogenation of ArX is of very recent interest [4].
There are three kinds of mechanism reported for the AreCl bond
cleavage. First is the oxidative addition mechanism. Oxidative
addition mechanism usually happens with electron rich d8 and d10
metal complexes [5]. For example, RhI(PNP) (PNP ¼ bis(2-(diiso-
propylphosphino)-4-methylphenyl)-amino), reacts with ArCl to give
the AreCl bond oxidative addition product [5a]. The AreCl bond can
also be cleaved through oxidative addition to the Pd center of
Pd0(PtBu3)2 at 80 ꢀC [5e]. Secondly, the AreCl bond can be cleaved
through chlorine atom abstraction. The chlorine atom of ArCl is
abstracted by LCo0(N2) (L ¼ 2,6-bis[2,6-dimethylphenyliminoethyl]
pyridine), which is generated from LCoICH2SiMe3 and H2, to give
LCoCl and Ar radical. The Ar radical further reacts with another
LCo0(N2) to give LCoAr and N2 [6]. Thirdly, the AreCl bond can also
be cleaved by metalloradical ipso-substitution addition-elimination
cleaves the AreCl bond to give IrIII(ttp)Ar [7].
Due to the high bond dissociation energy of AreCl bond
(95 kcal/mol for Ph-Cl), AreH bond cleavage may compete with the
AreCl bond cleavage (112 kcal/mol for Ph-H) [8]. For example,
when the IrI(PNP) complex, which is generated from Ir(PNP)H2 and
norbornene, reacts with ArCl to first give the kinetic AreH bond
oxidative addition product and then converts to the thermody-
namic AreCl bond oxidative addition product [9]. Moreover, the
reaction between [Cp*2ZrIVCH3]þ and chlorobenzene gives ortho-C-
H bond activation first, by the coordination effect of ortho-chlorine
to Zr. Then, the AreCl bond is cleaved by b-Cl elimination [10].
Our group has reported the selective AreCl bond cleavage by
iridium porphyrin. A metalloradical ipso-substitution addition-
elimination mechanism has been proposed for the AreCl bond
cleavage process (Scheme 1) [7]. With the selective AreCl bond
cleavage by iridium porphyrin, we thus have extended our studies
to rhodium porphyrin.
2. Results and discussion
2.1. Conditions optimization of AreCl bond cleavage
Based on the optimal conditions in the reported AreI and AreBr
bond cleavage with Rh(ttp)Cl [11], 10 equivalents of KOH and 10
equivalents of ArCl in benzene at 120 ꢀC were applied for investi-
gation of the AreCl bond cleavage with Rh(ttp)Cl (Table 1, entry 1).
* Corresponding author.
E-mail address: ksc@cuhk.edu.hk (K.S. Chan).
http://dx.doi.org/10.1016/j.jorganchem.2015.05.039
0022-328X/© 2015 Elsevier B.V. All rights reserved.

Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
83
Table 2
Substrate Scopes of AreCl bond cleavage with Rh(ttp)Cl.
Scheme 1. Proposed mechanism for AreCl bond cleavage with Ir(ttp) (CO)Cl.
Entry
FG
Temp/ꢀC
CClA/%
1
H (2a)
150
150
150
150
150
200
150
150
3a (62)
3b (7)
However, no AreCl bond cleavage product Rh(ttp)Ph was obtained
after 6 h. Then, THF and PhCN were used as the solvent. No Rh(ttp)
Ph was obtained neither (Table 1, entries 2 and 3). Since changing
the solvent was not effective to achieve the AreCl bond cleavage,
the substrate concentration was increased. When 200 equivalents
of PhCl was used at 150 ꢀC, 31% yield of Rh(ttp)Ph was obtained
(Table 1, entry 5). When the equivalent of PhCl was increased to
780, which is in solvent-free conditions, 62% yield of Rh(ttp)Ph was
isolated (Table 1, entry 6). In order to further increase the product
yield, the temperature effect was investigated. At 120 ꢀC, only 30%
yield of Rh(ttp)Ph was obtained after 3 days (Table 1, entry 7).
When the reaction temperature was raised to 200 ꢀC, although the
reaction rate is faster, the yield of Rh(ttp)Ph was still 61% (Table 1,
entry 8). Therefore, the better functional group compatible of
150 ꢀC was used for further investigations.
2a
3b
4
OMe (2b)
Me (2c)
tBu (2d)
Cl (2e)
F (2f)
CF3 (2g)
NO2 (2h)
3c (29)
3d (85)
3e (47)
3f (63)
3g (74)
3h (71)
5
6c
7
8
a
Rh(ttp)Me (4) was isolated in 43% yield and Rh(ttp)CH2O(4-chlorophenyl) (5)
was isolated in 41% yield.
b
Rh(ttp) (4-chlorobenzyl) (6) was isolated in 11% yield.
Rh(ttp) (4-chlorophenyl) (3e) was isolated in 6% yield.
c
2.3. Mechanistic investigation for AreCl bond cleavage
In order to gain further mechanistic understandings of the
AreCl bond cleavage, mechanistic investigations were carried out.
It has been reported that Rh(ttp)OH, synthesized by ligand substi-
tution with KOH, exists in equilibria with Rh2(ttp)2, Rh(ttp)H and
Rh(ttp)- (Scheme 2) [13]. Since the thermal reductive elimination of
Rh(ttp)OH to Rh2(ttp)2 is very rapid at 120 ꢀC within 1 h [13a],
Rh2(ttp)2, Rh(ttp)H and Rh(ttp)- are sufficiently long lived to be
viable intermediates. Table 3 lists the results of these complexes
with chlorobenzene. Among the three rhodium complexes,
Rh2(ttp)2, which in thermo equilibrium with Rh(ttp) monomer [14],
reacted the fastest with highest total yield (Table 3). Reactions of
chlorobenzene with Rh(ttp)H and Rh(ttp)ꢁKþ also occurred, how-
ever, with much longer reaction times. These two complexes thus
play minor importance. Therefore, Rh2(ttp)2, or more accurately
Rh(ttp) monomer, is the most likely intermediate for AreCl bond
cleavage, likely by a metalloradical substitution as we have previ-
ously established for related iridium (II) porphyrin activation of Ar-
X bonds [7,11]. Two further detailed Ar-X bond cleavage processes
of the metalloradical AreCl bond cleavage still exist. One is the
halogen atom transfer mechanism, and the other is the metal-
loradical ipso-substitution mechanism (Scheme 3). For the halogen
atom transfer mechanism, the aryl radical is generated through
cleavage of the strong AreCl bond (Scheme 3, step i). The aryl
radical can either react with Rh(ttp) radical to give Rh(ttp)Ar or
with chlorobenzene to give biaryl through radical substitution re-
action (Scheme 3, step ii). For the metalloradical ipso-substitution
2.2. Substrate scope of AreCl bond cleavage
Various ArCl reacted with Rh(ttp)Cl to give the corresponding
AreCl bond cleavage products (Table 2). Electron rich 4-chloro-tert-
butylbenzene (2d), electron deficient 1,4-dichlorobenzene (2e), 4-
chlorobenzotrifluoride (2g) and 4-chloronitrobenzene (2h) reac-
ted smoothly with Rh(ttp)Cl to give moderate to high yields of
AreCl bond cleavage products (Table 2, entries 4, 5, 7 and 8).
However, substrates with reactive CeH and CeO bonds, such as 4-
chloroanisole (2b) and 4-chlorotoluene (2c), reacted with Rh(ttp)Cl
to give both the CeH or CeO bond cleavage products besides the
AreCl bond cleavage products (Table 2, entries 2 and 3) [12]. For 4-
chlorofluorobenzene (2f),
a
higher temperature 200 ꢀC was
employed since the AreF bond cleavage competed dominantly
with the AreCl bond cleavage at 150 ꢀC, which will be discussed in
the following section. At 150 ꢀC, still 6% yield of the AreF bond
cleavage product 3e was obtained (Table 2, entry 6).
Table 1
Conditions Optimization of AreCl Bond Cleavage with Rh(ttp)Cl.
mechanism, cleavage of the relative weaker carbonecarbon
p bond
in benzene and subsequent formation of cyclohexadienyl radical
intermediate [15], chlorine radical is then generated (Scheme 3,
Entry
Solvent
n
Temp/ꢀC
Time
Rh(ttp)Ph yield/%
1
2
3
4
5
6
7
8
benzene
THF
10
10
10
120
120
120
150
150
150
120
200
6 h
3 h
3 d
4 h
3 h
4 h
3 d
2 h
/
/
/
/
31
62
30
61
PhCN
benzene
benzene
S.F.a
10
200
780
780
780
S.F.a
S.F.a
Scheme 2. Equilibria between rhodium porphyrin intermediates under basic
conditions.
a
S.F. ¼ solvent-free.

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Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
bond cleavage can be achieved at 120 ꢀC with 10 equivalents of KOH
Table 3
Possible intermediate for AreCl bond cleavage.
and 100 equivalents of 4-chlorofluorobenzene in benzene solvent.
To ensure the product ratios are kinetic, the stability of the
rhodium porphyrin aryls was examined. Rh(ttp) (4-chlorophenyl)
(3e) and Rh(ttp) (4-fluorophenyl) (3f) were then reacted with 4-
chlorofluorobenzene under the reaction conditions (eqs (1) and
(2)). After 3 days, almost all the rhodium porphyrin aryls were
recovered. Thus, the product ratios obtained were kinetic ratios.
2.5. Mechanistic investigation of AreF bond cleavage
Entry Rh(ttp)X
Time Yield 3a/% Yield 1a/% Yield 3e/% Total yield/%
1
2
3
Rh2(ttp)2 1b 1 h
22
8
30
7
/
/
10
/
/
39
8
30
In order to find out the origin of the selectivity, mechanistic
investigations of AreF bond cleavage were carried out. The AreF
bond cleavage of fluorobenzene in benzene with KOH was achieved
with 77% yield of Rh(ttp)Ph (eq (3)). To rule out the possibility of
direct CeH activation of benzene, fluorobenzene was reacted with
Rh(ttp)Cl in benzene-d6 with 10 equivalents of KOH. Only Rh(ttp)Ph
in 50% yield was obtained without any Rh(ttp)Ph-d5 (eq (4)).
Moreover, Rh(ttp)C6H5 in C6D6 with KOH (10 equiv) at 120 ꢀC in 1
day did not exchange to give any Rh(ttp)C6D5, so Rh(ttp)Ph is not
formed from the AreH bond cleavage of benzene.
Rh(ttp)H 1c 1 d
Rh(ttp)ꢁKþ
1 d
1d
step iii). The chlorine radical can either react with Rh(ttp) radical to
give Rh(ttp)Cl or with chlorobenzene to give 1,4-dichlorobenzene
[15]. Rh(ttp) radical can further react with 1,4-dichlorobenzene,
which is more reactive than chlorobenzene towards radical sub-
stitution with iridium(II) porphyrin [15], to give Rh(ttp) (4-
chlorophenyl) (Scheme 3, step iv; Table 3, entry 1). Since Rh(ttp)
(4-chlorophenyl) was obtained from the reaction between
Rh2(ttp)2 and chlorobenzene, and no biaryl was observed by
GCeMS analysis, the metalloradical ipso-substitution mechanism
rather than the chlorine atom transfer process operates.
Then, Rh(ttp)H, Rh2(ttp)2 and Rh(ttp)- were tested with 1,4-
difluorobenzene or fluorobenzene. Neither Rh(ttp)H nor Rh2(ttp)2
gave any AreF bond cleavage product (Table 5, entries 1 and 2).
Rh(ttp)- however, reacted with fluorobenzene to give 40% yield of
Rh(ttp)Ph (3a) (Table 5, entry 3). Therefore, Rh(ttp)- is the most
reasonable intermediate for AreF bond cleavage through nucleo-
philic aromatic substitution mechanism as we have identified in
the iridium analogues in the AreF bond cleavage [16].
2.4. Competitive AreF and AreCl bond cleavage
Interestingly, during the substrate investigation of the AreCl
bond cleavage, it was found that the much stronger AreF bond
(~125 kcal/mol) [8] cleavage can compete with the AreCl bond
(~95 kcal/mol) [8] cleavage (Table 2, entry 6 and footnote c). We
therefore optimized the conditions to achieve selective AreF bond
cleavage. Initially, Rh(ttp)Cl reacted with 4-chlorofluorobenzene
under solvent-free conditions at 200 ꢀC to give the AreCl bond
cleavage product (3f) as the major product with 6% of the AreF
bond cleavage product (3e) (Table 4, entry 1). When the reaction
temperature was lowered to 150 ꢀC, the AreF bond cleavage
product Rh(ttp) (4-chlorophenyl) (3e) formed exclusively (Table 4,
entry 2). A lower reaction temperature at 120 ꢀC gave the AreF
bond cleavage product 3e in 92% yield almost exclusively (Table 4,
entry 3). Moreover, 100 equivalents of 4-chlorofluorobenzene was
enough for the selective AreF bond cleavage reaction (Table 4,
entry 4). However, in the polar solvent, THF, unknown complexes
together with only small amount AreF and AreCl bond cleavage
products were obtained (Table 4, entry 5). Therefore, selective AreF
Scheme 3. Possible mechanisms for AreCl bond cleavage.

Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
85
Table 4
Conditions optimization for the competitive AreF and AreCl bond cleavage with rhodium porphyrin complexes.
Entry
n
Temp/ꢀC
Time
Yield 3e (CFA)/%
Yield 3f (CClA)/%
Total yield/%
1
2
3
S.F.
S.F.
S.F.
100
100
200
150
120
120
120
1.5 h
2 h
10 h
1 d
6
82
92
91
10
63
trace
/
trace
6
69
82
92
91
16
4
5a
1 d
a
THF was used as solvent.
Table 5
Possible intermediate for AreF bond cleavage.
Entry
Rh(ttp)X
FG
Yield CFA/%
1
Rh2(ttp)2 1b
Rh(ttp)H 1c
Rh(ttp)ꢁKþ 1d
F
F
H
/
/
40
2
3a
a
18% Rh(ttp) (2-fluorophenyl) was obtained.
Scheme 4. Proposed mechanism for competitive AreCl and AreF Bond cleavage with
Rh(ttp)Cl.
homolytic cleavage of AreCl bond by Rh(ttp) radical operates.
Likely the homolysis of Rh2(ttp)2 into RhII(ttp) radical is much faster
than the reaction with KOH to give Rh(ttp)ꢁKþ, the AreCl bond
cleavage then becomes dominant. Therefore, the selectivity of
AreCl or AreF bond cleavage can be controlled by reaction tem-
perature and substrate concentration.
2.6. Proposed mechanism for competitive AreF and AreCl bond
cleavage
3. Conclusions
From the above mechanistic investigations, we suggest that the
AreCl bond is cleaved by RhII(ttp) radical through metalloradical
ipso-substitution, while the AreF bond is cleaved by Rh(ttp)-
through nucleophilic aromatic substitution (Scheme 4). From the
competitive AreF and AreCl bond cleavage reactions by Rh(ttp)Cl,
the AreF bond cleavage was selective at lower temperature (120 ꢀC)
and the AreCl bond cleavage was selective at higher temperature
(200 ꢀC). We reason the results as follows. First, the dissociation of
Rh2(ttp)2 to RhII(ttp) monomer requires high temperature. More-
over, at 120 ꢀC, Rh2(ttp)2 does not cleave the AreCl bond due to the
strong AreCl bond strength (95 kcal/mol) [8]. Thus, the Rh(ttp)- can
be generated under basic conditions and cleave the AreF bond at
lower temperature through nucleophilic substitution, which is a
heterolytic cleavage. At 200 ꢀC, in solvent-free conditions, the
In summary, the AreCl bond of aryl chlorides can be cleaved
successfully by Rh(ttp)Cl/KOH through metalloradical ipso-substi-
tution mechanism to give
a variety of Rh(ttp)Ar. For 4-
chlorofluorobenzene, selective AreF bond cleavage was achieved.
AreF bond cleavage by Rh(ttp)- through nucleophilic aromatic
substitution is identified. Selective AreF bond cleavage is achieved
at lower temperature and selective AreCl bond cleavage is achieved
at higher temperature.
4. Experimental section
Unless otherwise noted, all chemicals were obtained from
commercial suppliers and used without further purification.

86
Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
Hexane for chromatography was distilled from anhydrous calcium
chloride. Benzene and THF used as solvent were distilled from so-
dium. Thin-layer chromatography was performed on precoated
silica gel 60 F254 plates for thin-layer analyses for the reaction
mixture. All preparation reactions were carried out in a teflon
screw-head stoppered pressure tube in N2 heated in drilled holes in
an aluminum block. All reactions were carried out without light
irradiation by wrapping with aluminum foil. Silica gel (Merck, 70-
230 and 230e400 mesh) was used for column chromatography for
rhodium porphyrin aryls in air. Rh(ttp)Cl [17] Rh2(ttp)2 [18] Rh(ttp)
H [18] and Rh(ttp)ꢁNaþ [19] were prepared according to the liter-
ature procedures.
pump cycles, purged with N2 and heated at 150 ꢀC under N2 for
4 h. Excess benzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). No product
was isolated.
4.1.5. Reaction of Rh(ttp)Cl with PhCl, and KOH in benzene at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (7.0 mg, 0.125 mmol)
and PhCl (2a) (0.26 mL, 2.48 mmol) were added in benzene
(0.8 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 150 ꢀC under N2 for
3 h. Excess benzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp)Ph (3a) [11] (3.2 mg, 0.004 mmol, 31%) was collected.
1H NMR and 13C NMR spectra were recorded on a Bruker DPX-
300 at 300 MHz or Bruker AV400 spectrometer at 400 MHz and
Bruker DPX-300 at 75 MHz or Bruker AV400 at 100 MHz respec-
tively. Chemical shifts were reported with reference to the residual
Rh(ttp)Ph (3a) 1H NMR (CDCl3, 400 MHz)
2.69 (s, 12H), 4.75 (t, 2H, J ¼ 7.6 Hz), 5.22 (t, 1H, J ¼ 7.1 Hz), 7.52 (t,
8H, J ¼ 7.8 Hz), 8.00 (d, 4H, J ¼ 7.7 Hz), 8.06 (d, 4H, J ¼ 7.6 Hz), 8.75
(s, 8H).
d
0.26 (d, 2H, J ¼ 8.0 Hz),
solvent protons in C6D6 (
d
7.15 ppm) or in CDCl3 (
d
7.26 ppm) as the
internal standard. 19F NMR spectra were recorded on a Varian XL-
400 spectrometer at 376 MHz. Chemical shifts were referenced
with the external standard fluorine in C6H5CF3 using a sealed
melting point tube and put into the NMR tube (d ¼ 0.00 ppm).
Chemical shifts (d) were reported as part per million (ppm) in (d)
scale downfield from C7H5F3.Coupling constants (J) are reported in
4.1.6. Reaction of Rh(ttp)Cl with PhCl, and KOH at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in PhCl (2a) (1.0 mL, 9.53 mmol). The red
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 150 ꢀC under N2 for 4 h. Excess chloroben-
zene was removed by vacuum distillation. The red residue was
purified by column chromatography on silica gel eluting with a
solvent mixture of hexane/CH2Cl2 (1:1). Red solid Rh(ttp)Ph (3a)
[11] (6.3 mg, 0.007 mmol, 62%) was collected.
hertz (Hz) [20]. Chemical shifts (d) were reported as part per million
(ppm). Coupling constants (J) were reported in Hertz (Hz).
High-resolution mass spectra (HRMS) were performed on a
ThermoFinnigan MAT 95 XL mass spectrometer in fast atom
bombardment (FAB) mode using 3-nitrobenzyl alcohol (NBA) ma-
trix and CH2Cl2 as the solvent or in electrospray ionization (ESI)
mode using MeOH/CH2Cl2 (1/1) as the solvent.
4.1.7. Reaction of Rh(ttp)Cl with PhCl, and KOH at 120 ꢀC
4.1. Experimental procedure
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in PhCl (2a) (1.0 mL, 9.53 mmol). The red
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 120 ꢀC under N2 for 3 days. Excess chloro-
benzene was removed by vacuum distillation. The red residue was
purified by column chromatography on silica gel eluting with a
solvent mixture of hexane/CH2Cl2 (1:1). Red solid Rh(ttp)Ph (3a)
[11] (3.1 mg, 0.004 mmol, 30%) was collected.
4.1.1. Reaction of Rh(ttp)Cl with PhCl, and KOH in benzene
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (7.0 mg, 0.125 mmol)
and PhCl (2a) (0.013 mL, 0.124 mmol) were added in benzene
(1.0 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 120 ꢀC under N2 for
6 h. Excess benzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). No product
was isolated.
4.1.8. Reaction of Rh(ttp)Cl with PhCl, and KOH at 200 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in PhCl (2a) (1.0 mL, 9.53 mmol). The red
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 200 ꢀC under N2 for 2 h. Excess chloroben-
zene was removed by vacuum distillation. The red residue was
purified by column chromatography on silica gel eluting with a
solvent mixture of hexane/CH2Cl2 (1:1). Red solid Rh(ttp)Ph (3a)
[11] (6.2 mg, 0.007 mmol, 61%) was collected.
4.1.2. Reaction of Rh(ttp)Cl with PhCl, and KOH in THF
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (7.0 mg, 0.125 mmol)
and PhCl (2a) (0.013 mL, 0.124 mmol) were added in THF (1.0 mL).
The red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 120 ꢀC under N2 for 3 h. Excess THF
was removed by vacuum distillation. The red residue was purified
by column chromatography on silica gel eluting with a solvent
mixture of hexane/CH2Cl2 (1:1). No product was isolated.
4.1.9. Reaction of Rh(ttp)Cl with 4-chloroanisole, and KOH at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-chloroanisole (2b) (1.0 mL). The red
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 150 ꢀC under N2 for 1 day. Excess 4-
chloroanisole was removed by vacuum distillation. The red res-
idue was purified by column chromatography on silica gel eluting
with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid Rh(ttp) (4-
methoxyphenyl) (3b) [11] (4.0 mg, 0.001 mmol, 7%), Rh(ttp)Me (4)
[12b] (0.7 mg, 0.005 mmol, 43%) and Rh(ttp)CH2O(4-chlorophenyl)
(5) (4.0 mg, 0.005 mmol, 41%) were collected. Rh(ttp) (4-
4.1.3. Reaction of Rh(ttp)Cl with PhCl, and KOH in PhCN
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (7.0 mg, 0.125 mmol)
and PhCl (2a) (0.013 mL, 0.124 mmol) were added in PhCN (1.0 mL).
The red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 120 ꢀC under N2 for 3 days. Excess
PhCN was removed by vacuum distillation. The red residue was
purified by column chromatography on silica gel eluting with a
solvent mixture of hexane/CH2Cl2 (1:1). No product was isolated.
4.1.4. Reaction of Rh(ttp)Cl with PhCl, and KOH in benzene at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (7.0 mg, 0.125 mmol)
and PhCl (2a) (0.013 mL, 0.124 mmol) were added in benzene
(1.0 mL). The red mixture was degassed for three freeze-thaw-
methoxyphenyl) (3b) 1H NMR (CDCl3, 400 MHz)
d 0.15 (d, 2H,
J ¼ 7.9 Hz), 2.69 (s, 12H), 2.77 (s, 3H), 4.44 (d, 2H, J ¼ 9.1 Hz), 7.53 (t,
8H, J ¼ 6.6 Hz), 8.01 (d, 4H, J ¼ 7.4 Hz), 8.06 (d, 4H, J ¼ 7.4 Hz), 8.76
(s, 8H). Rh(ttp)Me (4) 1H NMR (CDCl3, 400 MHz)
d
ꢁ5.82 (d, 3H,

Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
87
J ¼ 3.0 Hz), 2.96 (s, 12H), 7.53 (d, 8H, J ¼ 7.5 Hz), 8.01 (dd, 4H, J ¼ 2.4,
8.4 Hz), 8.07 (dd, 4H, J ¼ 2.4, 8.4 Hz), 8.73 (s, 8H). Rh(ttp)CH2O(4-
chlorophenyl) (5), Rf ¼ 0.72 (hexane/CH2Cl2 ¼ 1:1). 1H NMR
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp) (4-fluorophenyl) (3f) [11] (6.5 mg, 0.008 mmol, 63%) was
collected. Rh(ttp) (4-fluorophenyl) (3f) 1H NMR (CDCl3, 300 MHz)
(CDCl3, 400 MHz)
d
ꢁ1.83 (d, 2H, J ¼ 3.2 Hz), 2.71 (s, 12H), 3.56 (d,
d
0.16 (dd, 2H, 4JH-F ¼ 1.8, J ¼ 8.9 Hz), 2.69 (s, 12H), 4.55 (dd, 2H, 3JH-
¼ 8.6, J ¼ 8.9 Hz), 7.54 (d, 8H, J ¼ 6.3 Hz), 7.99 (dd, 4H, J ¼ 2.2,
2H, J ¼ 8.8 Hz), 6.33 (d, 2H, J ¼ 8.8 Hz), 7.54 (m, 8H), 8.00 (m, 8H),
8.71 (s, 8H). Calcd. For (C55H42ClN4ORh)þ: m/z 912.2097 Found: m/z
912.2094.
F
8.5 Hz), 8.02 (dd, 4H, J ¼ 2.2, 8.7 Hz), 8.74 (s, 8H).
4.1.14. Reaction of Rh(ttp)Cl with 4-chlorobenzotrifluoride, and
KOH at 150 ꢀC
4.1.10. Reaction of Rh(ttp)Cl with 4-chlorotoluene, and KOH at
150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-chlorobenzotrifluoride (2g) (1.0 mL).
The red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 150 ꢀC under N2 for 1 day. Excess 4-
chlorobenzotrifluoride was removed by vacuum distillation. The
red residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp) (4-trifluoromethylphenyl) (3g) (8.1 mg, 0.008 mmol, 74%)
was collected. Rh(ttp) (4-trifluoromethylphenyl) (3g), Rf ¼ 0.58
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-chlorotoluene (2c) (1.0 mL). The red
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 150 ꢀC under N2 for 1 day. Excess 4-
chlorotoluene was removed by vacuum distillation. The red res-
idue was purified by column chromatography on silica gel eluting
with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid Rh(ttp) (4-
toly) (3c) [11] (3.0 mg, 0.003 mmol, 29%), Rh(ttp) (4-Cl)Bn (9) [12a]
(1.2 mg, 0.001 mmol, 11%) were collected. Rh(ttp) (4-toly) (3c) 1H
(hexane/CH2Cl2 ¼ 1:1). 1H NMR (CDCl3, 400 MHz)
d 0.34 (d, 2H,
NMR (CDCl3, 400 MHz)
d
0.17 (d, 2H, J ¼ 6.9 Hz), 1.08 (s, 3H), 2.69 (s,
J ¼ 8.3 Hz), 2.69 (s, 12H), 5.01 (d, 2H, J ¼ 8.7 Hz), 7.54 (t, 8H,
12H), 4.61 (d, 2H, J ¼ 8.4 Hz), 7.52 (t, 8H, J ¼ 6.0 Hz), 8.01 (d, 4H,
J ¼ 8.7 Hz), 8.05 (d, 4H, J ¼ 8.6 Hz), 8.75 (s, 8H). Rh(ttp) (4-Cl)Bn (9)
J ¼ 6.5 Hz), 8.00 (d, 4H, J ¼ 7.6 Hz), 8.06 (d, 4H, J ¼ 7.6 Hz), 8.80 (s,
8H). 13C NMR (CDCl3, 100 MHz)
d 21.69, 30.00, 120.09, 123.10,
1H NMR (CDCl3, 400 MHz)
d
ꢁ3.83 (d, 2H, J ¼ 3.9 Hz), 2.71 (s, 12H),
127.62, 128.88, 131.62, 131.93, 133.88, 134.26, 137.59, 138.98, 143.10.
2.84 (d, 2H, J ¼ 8.4 Hz), 5.80 (d, 2H, J ¼ 8.4 Hz), 7.55 (t, 8H,
J ¼ 7.2 Hz), 7.96 (d, 4H, J ¼ 8.0 Hz), 8.06 (d, 4H, J ¼ 7.8 Hz), 8.69 (s,
8H).
Calcd. for (C55H40F3N4Rh)þ: m/z 916.2255 Found: m/z 916.2258.
4.1.15. Reaction of Rh(ttp)Cl with 4-nitrochlorobenzene, and KOH at
150 ꢀC
4.1.11. Reaction of Rh(ttp)Cl with 4-chloro-tert-butylbenzene, and
KOH at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-nitrochlorobenzene (2h) (1.0 mL).
The red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 150 ꢀC under N2 for 1 day. Excess 4-
nitrochlorobenzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp) (4-nitrophenyl) (3h) [11] (7.6 mg, 0.008 mmol, 71%) was
collected. Rh(ttp) (4-nitrophenyl) (3h) 1H NMR (CDCl3, 400 MHz)
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-chloro-tert-butylbenzene (2d)
(1.0 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 150 ꢀC under N2 for 1
day. Excess 4-chloro-tert-butylbenzene was removed by vacuum
distillation. The red residue was purified by column chromatog-
raphy on silica gel eluting with a solvent mixture of hexane/CH2Cl2
(1:1). Red solid Rh(ttp) (4-tert-butylphenyl) (3d) [11] (9.2 mg,
0.010 mmol, 85%) was collected. Rh(ttp) (4-tert-butylphenyl) (3d)
d
0.37 (d, 2H, J ¼ 8.2 Hz), 2.70 (s,12H), 5.61 (d, 2H, J ¼ 9.1 Hz), 7.55 (t,
8H, J ¼ 5.9 Hz), 8.00 (d, 4H, J ¼ 7.2 Hz), 8.06 (d, 4H, J ¼ 7.1 Hz), 8.83
1H NMR (CDCl3, 400 MHz)
2.70 (s, 12H), 4.80 (d, 2H, J ¼ 8.8 Hz), 7.53 (t, 8H, J ¼ 6.4 Hz), 8.03 (d,
4H, J ¼ 7.2 Hz), 8.08 (d, 4H, J ¼ 7.5 Hz), 8.78 (s, 8H).
d
0.23 (d, 2H, J ¼ 8.5 Hz), 0.35 (s, 9H),
(s, 8H).
4.1.16. Reaction of Rh2(ttp)2 with PhCl
Rh2(ttp)2 (1b) (9.3 mg, 0.006 mmol) was added in PhCl (2a)
(1.0 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 120 ꢀC under N2 for
1 h. Excess chlorobenzene was removed by vacuum distillation. The
red residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp)Cl (1a) (0.7 mg, 0.001 mmol, 7%), Rh(ttp) (4-chlorophenyl)
(3e) [11] (1.0 mg, 0.001 mmol, 10%) and Rh(ttp)Ph (3a) [11] (2.2 mg,
0.003 mmol, 22%) were collected.
4.1.12. Reaction of Rh(ttp)Cl with 1,4-dichlorobenzene, and KOH at
150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 1,4-dichlorobenzene (2e) (1.0 mL). The
red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 150 ꢀC under N2 for 1 day. Excess 1,4-
dichlorobenzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp) (4-chlorophenyl) (3e) [11] (5.0 mg, 0.006 mmol, 47%) was
collected. Rh(ttp) (4-chlorophenyl) (3e) 1H NMR (CDCl3, 400 MHz)
4.1.17. Reaction of Rh(ttp)H with PhCl
Rh(ttp)H (1c) (9.3 mg, 0.012 mmol) was added into PhCl (2a)
(1.0 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 120 ꢀC under N2 for 1
day. Excess chlorobenzene was removed by vacuum distillation.
The red residue was purified by column chromatography on silica
gel eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp)Ph (3a) [11] (0.8 mg, 0.001 mmol, 8%) was collected.
d
0.16 (d, 2H, J ¼ 8.8 Hz), 2.70 (s,12H), 4.78 (d, 2H, J ¼ 8.8 Hz), 7.54 (t,
8H, J ¼ 6.0 Hz), 8.00 (d, 4H, J ¼ 4.5 Hz), 8.07 (d, 4H, J ¼ 4.6 Hz), 8.79
(s, 8H).
4.1.13. Reaction of Rh(ttp)Cl with 4-chlorofluorobenzene, and KOH
at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol) and KOH (7.0 mg,
0.125 mmol) were added in 4-chlorofluorobenzene (2f) (1.0 mL).
The red mixture was degassed for three freeze-thaw-pump cycles,
purged with N2 and heated at 200 ꢀC under N2 for 1 day. Excess 4-
chlorofluorobenzene was removed by vacuum distillation. The red
residue was purified by column chromatography on silica gel
4.1.18. Reaction of Rh(ttp)ꢁKþ with PhCl
Rh(ttp)ꢁKþ (1d) (9.3 mg, 0.012 mmol) was added into PhCl (2a)
(1.0 mL). The red mixture was degassed for three freeze-thaw-
pump cycles, purged with N2 and heated at 120 ꢀC under N2 for 1
day. Excess chlorobenzene was removed by vacuum distillation.

88
Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
The red residue was purified by column chromatography on silica
gel eluting with a solvent mixture of hexane/CH2Cl2 (1:1). Red solid
Rh(ttp)Ph (3a) [11] (3.0 mg, 0.004 mmol, 30%) was collected.
4.1.24. Reaction between Rh(ttp) (4-fluorophenyl) and 4-
fluorochlorobenzene with 10 equiv KOH at 120 ꢀC for 3 days in
benzene solvent
Rh(ttp) (4-fluorophenyl) (3f) (10.0 mg, 0.010 mmol), KOH
(6.2 mg, 0.11 mmol, 10 equiv) and 4-fluorochlorobenzene (2f)
(0.24 ml, 200 equiv) were added in benzene (1.0 mL). The mixture
was degassed for three freeze-thaw-pump cycles, purged with N2
and heated at 120 ꢀC for 3 day. Excess benzene was removed by
vacuum distillation. The brown residue was purified by column
chromatography on alumina eluting with a mixture of hexane/
CH2Cl2 (2:1). Purple solid of Rh(ttp) (4-fluorophenyl) (3f) [11]
(9.3 mg, 0.010 mmol, 93%) and Rh(ttp) (4-chlorophenyl) (3e) [11]
(trace, < 5%) were isolated.
4.1.19. Reaction between Rh(ttp)Cl and 4-chlorofluorobenzene with
10 equiv KOH at 200 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (6.7 mg, 0.12 mmol,
10 equiv) were added to 4-chlorofluorobenzene (2f) (1.0 mL). The
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 200 ꢀC for 1.5 h. Excess 4-
chlorofluorobenzene was removed by vacuum distillation. The
brown residue was purified by column chromatography on silica
gel eluting with a mixture of hexane/CH2Cl2 (1:1). Purple solid of
Rh(ttp) (4-chlorophenyl) (3e) [11] (0.7 mg, 0.001 mmol, 6%) and
Rh(ttp) (4-fluorophenyl) (3f) [11] (7.2 mg, 0.008 mmol, 63%) were
isolated.
4.1.25. Reaction between Rh(ttp) (4-chlorophenyl) and 4-
chlorofluorobenzene with 10 equiv KOH at 200 ꢀC for 3 days
Rh(ttp) (4-chlorophenyl) (3e) (10.0 mg, 0.010 mmol), KOH
(6.2 mg, 0.11 mmol, 10 equiv) were added into 4-
fluorochlorobenzene (2f) (1.0 mL). The mixture was degassed for
three freeze-thaw-pump cycles, purged with N2 and heated at
200 ꢀC for 3 days. Excess 4-chlorofluorobenzene was removed by
vacuum distillation. The brown residue was purified by column
chromatography on alumina eluting with a mixture of hexane/
CH2Cl2 (2:1). Purple solid of Rh(ttp) (4-chlorophenyl) (3e) [11]
(9.8 mg, 0.010 mmol, 98%) and Rh(ttp) (4-fluorophenyl) (3f) [11]
(trace, < 5%) were isolated.
4.1.20. Reaction between Rh(ttp)Cl and 4-chlorofluorobenzene with
10 equiv KOH at 150 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (6.7 mg, 0.12 mmol,
10 equiv) were added to 4-chlorofluorobenzene (2f) (1.0 mL). The
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 150 ꢀC for 2 h. Excess 4-chlorofluorobenzene
was removed by vacuum distillation. The brown residue was pu-
rified by column chromatography on silica gel eluting with a
mixture of hexane/CH2Cl2 (1:1). Purple solid of Rh(ttp) (4-
chlorophenyl) (3e) [11] (9.6 mg, 0.010 mmol, 82%) and Rh(ttp) (4-
fluorophenyl) (3f) [11] (trace, < 5%) were isolated.
4.1.26. Reaction of fluorobenzene with Rh(ttp)Cl in benzene
A mixture of Rh(ttp)Cl (1a) (30.0 mg, 0.037 mmol), 10 equiv of
KOH (20.8 mg, 0.37 mmol) and fluorobenzene (0.30 mL, 3.7 mmol)
with benzene (1.50 mL, 18.5 mmol) were degassed for three freeze-
thaw-pump cycles and heated at 120 ꢀC under N2 for 1 d. The
solvent was then removed in vacuum and the red crude mixture
was purified by silica gel column chromatography eluting with a
solvent mixture of hexane: CH2Cl2 (1:1) to give Rh(ttp)Ph (3a) [11]
(23.1 mg, 0.028 mmol, 77%).
4.1.21. Reaction between Rh(ttp)Cl and 4-chlorofluorobenzene with
10 equiv KOH at 120 ꢀC
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (6.7 mg, 0.12 mmol,
10 equiv) were added to 4-chlorofluorobenzene (2f) (1.0 mL). The
mixture was degassed for three freeze-thaw-pump cycles, purged
with N2 and heated at 120 ꢀC for 10 h. Excess 4-
chlorofluorobenzene was removed by vacuum distillation. The
brown residue was purified by column chromatography on silica
gel eluting with a mixture of hexane/CH2Cl2 (1:1). Purple solid of
Rh(ttp) (4-chlorophenyl) (3e) [11] (10.1 mg, 0.011 mmol, 92%) was
isolated.
4.1.27. Reaction of fluorobenzene with Rh(ttp)Cl in C6D6
A mixture of Rh(ttp)Cl (1a) (30.0 mg, 0.037 mmol), 10 equiv of
KOH (20.8 mg, 0.37 mmol) and fluorobenzene (0.30 mL, 3.7 mmol)
with C6D6 (1.50 mL, 18.5 mmol) were degassed for three freeze-
ethawpump cycles and heated at 120 ꢀC under N2 for 1 d. The
solvent was then removed in vacuum and the red crude mixture
was purified by silica gel column chromatography eluting with a
solvent mixture of hexane: CH2Cl2 (1:1) to give Rh(ttp)Ph (3a) [11]
(15.3 mg, 0.018 mmol, 50%).
4.1.22. Reaction between Rh(ttp)Cl and 4-chlorofluorobenzene with
10 equiv KOH at 120 ꢀC in benzene solvent
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (6.7 mg, 0.12 mmol,
10 equiv) and 4-chlorofluorobenzene (2f) (0.15 mL, 100 equiv) were
added in benzene (1.0 mL). The mixture was degassed for three
freeze-thaw-pump cycles, purged with N2 and heated at 120 ꢀC for
1 day. Excess benzene was removed by vacuum distillation. The
brown residue was purified by column chromatography on silica
gel eluting with a mixture of hexane/CH2Cl2 (1:1). Purple solid of
Rh(ttp) (4-chlorophenyl) (3e) [11] (10.7 mg, 0.011 mmol, 91%) and
Rh(ttp) (4-fluorophenyl) (3f) [11] (trace, < 5%) were isolated.
4.1.28. Reaction of 1,4-difluorobenzene with Rh2(ttp)2
A solution of Rh2(ttp)2 (1b) (15.0 mg, 0.010 mmol), 1,4-
difluorobenzene (0.19 mL, 1.9 mmol) in benzene (0.93 mL,
8.5 mmol) was degassed for three freeze-thaw-pump cycles and
heated at 120 ꢀC under N2 for 1 d. The solvent was then removed in
vacuum and the red crude mixture was purified by silica gel column
chromatography eluting with a mixture of hexane: CH2Cl2 (1:1) to
give an unidentified mixture of complexes.
4.1.23. Reaction between Rh(ttp)Cl and 4-chlorofluorobenzene with
10 equiv KOH at 120 ꢀC in THF
Rh(ttp)Cl (1a) (10.0 mg, 0.012 mmol), KOH (6.7 mg, 0.12 mmol,
10 equiv) and 4-chlorofluorobenzene (2f) (0.15 mL, 100 equiv) were
added in THF (1.0 mL). The mixture was degassed for three freeze-
thaw-pump cycles, purged with N2 and heated at 120 ꢀC for 1 day.
Excess THF was removed by vacuum distillation. The brown residue
was purified by column chromatography on silica gel eluting with a
mixture of hexane/CH2Cl2 (1:1). Purple solid of Rh(ttp) (4-
chlorophenyl) (3e) [11] (1.0 mg, 0.001 mmol, 10%) and Rh(ttp) (4-
fluorophenyl) (3f) [11] (0.7 mg, 0.001 mmol, 6%) were isolated.
4.1.29. Reaction of 1,4-difluorobenzene with Rh(ttp)H
A
solution of Rh(ttp)H (1c) (15.0 mg, 0.019 mmol), 1,4-
difluorobenzene (0.19 mL, 1.9 mmol) in benzene (0.93 mL,
8.5 mmol) was degassed for three freeze-thaw-pump cycles and
heated at 120 ꢀC under N2 for 1 d. The solvent was then removed in
vacuum and the red crude mixture was purified by silica gel column
chromatography eluting with a mixture of hexane: CH2Cl2 (1:1) to
give an unidentified mixture of complexes.

Y.Y. Qian et al. / Journal of Organometallic Chemistry 791 (2015) 82e89
89
4.1.30. Reaction of fluorobenzene with Rh(ttp)ꢁKþ precursor
Rh(ttp)SiEt3 with KOH
(b) S. Safe, Toxicology 21 (1990) 51.
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(2009) 3812;
A mixture of Rh(ttp)SiEt3 (15.0 mg, 0.017 mmol) and 10 equiv of
KOH (9.6 mg, 0.17 mmol) and fluorobenzene (0.17 mL, 1.7 mmol) in
benzene (1 mL) were degassed for three freeze-thaw-pump cycles
and heated at 120 ꢀC under N2 for 4 d. The solvent was then
removed by vacuum and the red crude mixture was purified by
silica gel column chromatography eluting with a mixture of hex-
(d) S. Akzinnay, F. Bisaro, C.S.J. Cazin, Chem. Commun. (2009) 5752;
(e) K.A. Cannon, M.E. Geuther, C.K. Kelly, S. Lin, A.H.R. MacArthur, Organo-
metallics 30 (2011) 4067.
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(b) K.A.P. Payne, C.P. Quezada, K. Fisher, M.S. Dunstan, F.A. Collins, H. Sjuts,
C. Levy, S. Hay, S.E.J. Rigby, David Leys, Nature 517 (2015) 513.
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Chem. Soc. 128 (2006) 2808;
ane: CH2Cl2 (1:1) to give Rh(ttp)Ph (3a) (6.0 mg, 7 mmol, 40%) and
Rh(ttp) (2-fluorophenyl) (2.7 mg, 3
mmol, 18%). Rh(ttp) (2-fluo-
rophenyl) Rf ¼ 0.58 (hexane: CH2Cl2 ¼ 1:1). 1H NMR (CDCl3,
(b) Y. Shi, M. Li, Q. Hu, X. Li, H. Sun, Organometallics 28 (2009) 2206;
300 MHz)
d
0.01 (m, 1H), 2.69 (s, 12H), 4.48 (t, 1H, J ¼ 7.3 Hz), 4.68
€
(c) Y. Chen, H. Sun, U. Florke, X. Li, Organometallics 27 (2008) 270;
(dd, 1H, J ¼ 7.3, 1JH-F ¼ 8.3 Hz), 5.28 (dd, 1H, J ¼ 7.3, 7.5 Hz) 7.53 (t,
8H, J ¼ 7.3 Hz), 8.02 (dd, 4H, J ¼ 2.2, 8.6 Hz), 8.07 (dd, 4H, J ¼ 2.2,
(d) J. Blum, M. Weitzberg, J. Organomet. Chem. 122 (1976) 261;
(e) F. Barrios-Landeros, B.P. Carrow, J.F. Hartwig, J. Am. Chem. Soc. 131 (2009)
8141;
(f) T.T. Tsou, J.K. Kochi, J. Am. Chem. Soc. 101 (1979) 6319;
(g) D.S. Surry, S.L. Buchwald, Chem. Sci. 1 (2010) 13.
8.6 Hz), 8.79 (s, 8H). 13C NMR (CDCl3, 75 MHz)
d
21.76, 107.43 (d, 1JC-
1
¼ 25.2 Hz), 112.10, (d, JC-Rh ¼ 27.8 Hz), 119.43, 122.09, 122.87,
F
127.52, 131.75, 132.30, 133.75, 134.25, 137.38, 139.18, 143.55. 19F
[6] (a) D. Zhu, F.F.B.J. Janssen, P.H.M. Budzelaar, Organometallics 29 (2010) 1897;
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(c) D. Zhu, I. Thapa, I. Korobkov, S. Gambarotta, P.H.M. Budzelaar, Inorg. Chem.
50 (2011) 9879.
NMR (CDCl3, 376 MHz)
d
ꢁ45.15 (s, 1F, o-F). Calcd for
(C54H40N4FRh)þ: m/z 866.2238. Found: m/z 866.2287.
[7] C.W. Cheung, K.S. Chan, Organometallics 30 (2011) 4999.
[8] Y.R. Luo, Comprehensive Handbook of Chemical Bond Energies, CRC Press,
Boca Raton, FL, 2007.
Acknowledgments
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(b) H. Wu, M.B. Hall, Dalton Trans. (2009) 5933.
We thank the Research Grants Council (No 400212) of the
HKSAR and a Special Equipment Grant (SEG/CUHK09) from Uni-
versity Grants Committee for financial support.
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(b) H.S. Fung, Y.W. Chan, C.W. Cheung, K.S. Choi, S.Y. Lee, Y.Y. Qian, K.S. Chan,
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Appendix A. Supplementary data
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.jorganchem.2015.05.039.
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