Bis-imine-cyclometalated macrocycles: Synthesis, characterization and observation of solution behaviour

Article abstract of DOI:10.1039/c0dt01377c

A novel class of cyclometalated macrocycles [(Cp*Ir) ₂(R-NC-C₆H₂-CN-R)₂] ₂(pyrazine)₂·(OTf)₄ [R = Ph (4a), p-MeOC₆H₄ (4b), p-MeC₆H₄ (4c), p-ClC₆H₄ (4d), Me (4e)]; [(Cp*Rh) ₂(R-NC-C₆H₂-CN-R)₂] ₂(pyrazine)₂·(OTf)₄ [R = Ph (4a′), p-MeOC₆H₄ (4b′), p-MeC₆H₄ (4c′)] and [(Cp*Ir)₂(R-CN-C₆H ₄-NC-R)₂]₂(pyrazine)₂·(OTf) ₄ [R = Ph (5a), p-MeOC₆H₄ (5b)] was stepwise constructed through the double-site C-H activation of aromatic bis-imine substrates. The structures of binuclear complexes and tetranuclear macrocycles were confirmed by single-crystal X-ray diffraction. Isomers were found both in binuclear species and macrocyclic complexes. Flexible substrates led to the existence of isomers for binuclear species, yet gave no isomers after macrocyclic constructions; rigid ones, in contrast, led to isomers only for macrocyclic species. The isomers of tetranuclear macrocycles were thermodynamically stable to reversible transformation on a scale of days. Robust bonding and a certain degree of rigidity were invoked to explain the existence of isomers. This is the first example, to our knowledge, in which coordinated macrocycles containing half-sandwich Cp*M (M = Ir, Rh) fragments have been constructed, without a dynamic reversible process.

Full text of DOI:10.1039/c0dt01377c

View Article Online / Journal Homepage / Table of Contents for this issue
Dynamic Article Links
Dalton
Transactions
Cite this: Dalton Trans., 2011, 40, 4982
www.rsc.org/dalton
PAPER
Bis-imine-cyclometalated macrocycles: synthesis, characterization and
observation of solution behaviour†
Hao Li, Ying-Feng Han and Guo-Xin Jin*
Received 12th October 2010, Accepted 24th February 2011
DOI: 10.1039/c0dt01377c
A novel class of cyclometalated macrocycles [(Cp*Ir)2(R–N C–C6H2–C N–R)2]2-
(pyrazine)2·(OTf)4 [R = Ph (4a), p-MeOC6H4 (4b), p-MeC6H4 (4c), p-ClC6H4 (4d), Me (4e)];
[(Cp*Rh)2(R–N C–C6H2–C N–R)2]2(pyrazine)2·(OTf)4 [R = Ph (4a¢), p-MeOC6H4 (4b¢), p-MeC6H4
(4c¢)] and [(Cp*Ir)2(R–C N–C6H4–N C–R)2]2(pyrazine)2·(OTf)4 [R = Ph (5a), p-MeOC6H4 (5b)] was
stepwise constructed through the double-site C–H activation of aromatic bis-imine substrates. The
structures of binuclear complexes and tetranuclear macrocycles were confirmed by single-crystal X-ray
diffraction. Isomers were found both in binuclear species and macrocyclic complexes. Flexible
substrates led to the existence of isomers for binuclear species, yet gave no isomers after macrocyclic
constructions; rigid ones, in contrast, led to isomers only for macrocyclic species. The isomers of
tetranuclear macrocycles were thermodynamically stable to reversible transformation on a scale of days.
Robust bonding and a certain degree of rigidity were invoked to explain the existence of isomers. This is
the first example, to our knowledge, in which coordinated macrocycles containing half-sandwich Cp*M
(M = Ir, Rh) fragments have been constructed, without a dynamic reversible process.
Introduction
Coordination-driven self-assembly has proven to be an efficient
methodology for constructing well-defined metallosupramolec-
ular macrocycles and cages.1,2 In the past few years, several
groups including those of Severin,3 Therrien4 and ourselves5 have
explored the use of Cp*M (M = Ir, Rh) and (p-cymene)Ru
units as building blocks for discrete architectures. These half-
sandwich units have advantages in solubility, thermal stability and
flexibility in fine-tuning processes, and therefore, are suitable can-
didates for metallosupramolecular assembly.3 As recent research
has revealed, macrocycles/cages which contain Cp*M (M = Ir,
Rh) or (p-cymene)Ru groups show potential in selective guest
encapsulation,6 cation/anion recognition7 and drug delivery.8
The synthetic route to macrocycles containing half-sandwich
metals developed by our group involves “chelating and bridging
ligand” (Fig. 1), with two pairs of chelating site linking two
metal atoms.5,9 The macrocycle-constructing capabilities of such
ligands, with different coordinating sites, including OŸO–OŸO5,9a,b
and OŸN–OŸN,9c,d were investigated. Recently, we have reported
Fig. 1 Synthetic route of half-sandwich macrocycles using “chelating and
bridging ligands” as building blocks.
that the C–H activation of aromatic imines can direct the
iridium-mediated self-assembly, forming tetranuclear macrocycles
Shanghai Key Laboratory of Molecular Catalysis and Innovative Material,
(Scheme 1).10 The most important feature about such macrocycles,
Department of Chemistry, Fudan University, 200433, Shanghai, P. R.
compared with those containing the “chelating and bridging
ligands”, is the replacement of relatively dynamic M–O or M–
N bonds by robust M–C bonds. This can lead to an increase of
the structural stability.
To investigate the influence of M–C bonds on the metal-
losupramolecular macrocyclic systems, we designed a series of
China. E-mail: gxjin@fudan.edu.cn; Fax: +86-21-65641740; Tel: +86-21-
65643776
† CCDC reference numbers 744133 (1a), No. 744134 (1b), No. 744135 (1b¢),
744140 (2a), 744141 (2b), 744136 (3a), 744137 (3b), 744138 (3c), 744139
(3c¢) and 744142 (4a). For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/c0dt01377c. For crystallographic data
in CIF or other electronic format see DOI: 10.1039/c0dt01377c
4982 | Dalton Trans., 2011, 40, 4982–4993
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
Scheme 1 Synthesis of bis-imine-cyclometalated macrocycles.
bis-imine substrates (Fig. 2), which may provide different degrees
of rigidities to the cyclic structures. Detailed observations were
also performed on the solution behaviours of the resulting
cyclic complexes. Herein, we report the full characterization and
further exploration of the bis-imine-containing organometallic
macrocycles. Isomers of tetranuclear macrocycles were observed
when ligands provide both high rigidity and structural stability,
and are not be found when ligands contain rotation axes or labile
coordinate bonds to the metal centers.
cleavage of the C–H bond at room temperature.13 In light of the
Davies’ work, we performed analogous reactions based on bis-
imine substrate L1–L5.
When L1 was treated with [Cp*IrCl2]2 in the presence of an
excess of sodium acetate, significant change of colour was observed
from orange to dark red, affording the dark red solid 1a in
1
moderate yields (Scheme 2). The H NMR spectrum indicates
that two C–H bonds in the middle phenyl group were activated,
which was also confirmed by the single crystal structure. The two
activated C–H bonds were para, probably due to a steric hindrance
effect (Fig. 3a). The two Cp* groups and two Cl atoms adopted
trans-conformation, respectively, which minimized the energy of
the structure. The Ir–NCH N, Ir–CAr bond lengths and the CAr–Ir–
NCH angles are typical compared with those of reported Cp*Ir
N
cyclometalated complexes.12,14
Ligands L2–L5 could also undergo the same kind of reactions,
affording 1b–1e as major products. Effects of substituent groups
on the speed of reactions were observed (Scheme 2). For L2
and L3, which contain strong electron-donor groups, the double-
site cyclometalations occurred more quickly, whereas the rate of
formation of electron-acceptor-containing 1d was relatively slow.
This result could be explained by the different electron densities at
the N atoms, which affect the coordinating abilities.15 The Cp*Rh
group also proved to be capable of mediating the double-site
cyclometalations, giving 1a¢–1c¢ as major products (Scheme 2).
However, the reaction rates were lower than those of Cp*Ir. Single
crystal structures of 1b and 1b¢ were obtained (Fig. 3b, c).
Interestingly, two cyclometalation reactions of the same phenyl
group seemed favoured. When [Cp*IrCl2]2 and L1 reacted in
the ratio of 1 : 2, the major product was still 1b. Although
favored stoichiometrically, no mono-cyclometalated product was
found.
Fig. 2 Structures of bis-imine substrates.
Results and discussion
Bis-imine substrates H2L1–H2L7 can be synthesized using the
Schiff-base condensation reaction.11 When undergoing the cy-
clometalation, L1–L5 will give completely rigid structures,
whereas L6 and L7 will give free rotation axes, allowing the change
of directions between two metal centres.
Binuclear cyclometalated complexes of 1a–1e and 1a¢–1c¢
Davies et al. have reported the C–H activation of aromatic imine
substrates in the presence of sodium acetate.12 The acetate ion is
believed to act as both catalyst and base, promoting the facile
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4982–4993 | 4983
©

View Article Online
Scheme 2 Synthesis of 1a–1e and 1a¢–1c¢.
˚
Fig. 3 (a) ORTEP view of 1a (ellipsoids at the 30% probability level). Hydrogen atoms have been omitted for clarity. Selected bond lengths (A) and
angles (◦): Ir(1)–C(2) 2.029(4), Ir(1)–N(1) 2.102(4); C(2)–Ir(1)–N(1) 77.54(15), C(4)–N(1)–Ir(1) 115.8(3). (b) ORTEP view of 1b. Selected bond lengths
◦
˚
(A) and angles ( ): Ir(1)◦–C(2) 2.049(1), Ir(1)–N(1) 2.096(8); C(2)–Ir(1)–N(1) 77.60(41), C(4)–N(1)–Ir(1) 116.6(8). (c) ORTEP view of 1b¢. Selected bond
˚
lengths (A) and angles ( ): Rh(1)–C(2) 2.028(6), Rh(1)–N(1) 2.095(6); C(2)–Rh(1)–N(1) 78.41(21), C(4)–N(1)–Rh(1) 115.2(7).
Binuclear cyclometalated complexes of 2a and 2b
Synthesis and characterization of tetranuclear
bis-imine-cyclometalated macrocycles
Similarly to those of L1–L5, cyclometalations of L6 and L7
were performed in the presence of NaOAc, affording 2a and
2b, respectively (Scheme 3). The structures of 2a and 2b were
confirmed by single-crystal X-ray diffraction, showing that the
C–H activations occurred at the ortho-sites of two imine groups
(Fig. 4).
However, unlike the completely rigid species of complexes 1a–
e, both 2a and 2b gave evidence of isomers in solution. In the 1H
NMR spectra of 2a (Fig. 5), peaks attributed to the CH N group
and the Cp* groups were split into two equal parts, indicating
different chemical environments of the phenyl group. The existence
of isomers is probably due to the different configurations of the
metal atoms (Fig. 5). A similar phenomenon does not occur for
1a–e and 1a¢–1c¢.
Macrocycle-constructed reactions were performed, using the binu-
clear cyclometalated species as building blocks. After the treatment
with AgOTf, 1a–1e can reacted with bridging pyrazine ligands,
affording 3a–3e, respectively (Scheme 4). 1H NMR indicated
that the bis-imine substrates and bridging ligands were in a 1 : 1
ratio. Single-crystal X-ray diffraction studies for 3a–3c showed
tetranuclear macrocyclic structures (Fig. 6). 3a–3c were almost
˚
square, with dimensions of 6.96 and 6.98 A for Ir ◊ ◊ ◊ Ir non-
bonding distances in 3a and very similar dimensions for 3b and
3c. In all the three structures, the two middle phenyl groups in the
bis-imine substrates were parallel to each other, respectively, as
well as two pyrazine ligands. Cp*Rh-containing macrocycles can
also be synthesized using a similar protocol (Scheme 4), affording
Scheme 3 Synthesis of 2a and 2b.
This journal is
4984 | Dalton Trans., 2011, 40, 4982–4993
The Royal Society of Chemistry 2011
©

View Article Online
˚
˚
Fig. 4 (a) ORTEP view of 2a (ellipsoids at the 30% probability level). Hydrogen atoms have been omitted for clarity. Selected bond lengths (A) and
◦
angles ( ): Ir(1)–C(1) 2.030(6), Ir(1)–N(1) 2.092(4), N(1)–C(7) 1.292(7); C(1)–Ir(1)–N(1) 78.1(2). (b) ORTEP view of 2b. Selected bond lengths (A) and
angles (◦): Ir(1)–C(1) 2.049(1), Ir(1)–N(1) 2.096(8), N(1)–C(7) 1.289(5); C(1)–Ir(1)–N(1) 77.6(0).
Fig. 5 Top: two proposed structures of isomers of 2a; bottom: 1H NMR spectrum of 2a in CDCl3.
3a¢–3c¢. The single-crystal structure of 3c¢ reveals a tetranuclear
cyclic structure, similar to those of 3a–3c (Fig. 6d).
Complexes 2a and 2b could also react with pyrazine, after
treatment with AgOTf, giving 4a and 4b as products, respectively
(Scheme 5). Significant change of colour from yellow to red
after the addition of pyrazine indicated the coordination of N
atoms to the Ir centres. A tetranuclear rectangular single-crystal
structure of 4a was obtained (Fig. 7), with the dimensions of
Scheme 4 Synthesis of 3a–3e and 3a¢–3c¢.
The Royal Society of Chemistry 2011
This journal is
Dalton Trans., 2011, 40, 4982–4993 | 4985
©

View Article Online
◦
˚
Fig. 6 (a) Complex cation of 3a (C: gray, N: blue gray, O: red, Ir: blue). Selected bond lengths (A) and angles ( ): Ir(1)–C(1) 2.073(0), Ir(1)–N(1)
2.064(5), Ir(1)–N(2) 2.142(5), N(1)–C(2) 1.310(2); C(1)–Ir(1)–N(1) 77.2(6), N(1)–Ir(1)–N(2) 89.9(6), C(1)–Ir(1)–N(2) 86.0(2), (b) Complex cation of 3b.
◦
˚
Selected bond lengths (A) and angles ( ): Ir(1)–C(1) 2.019(9), Ir(1)–N(1) 2.067(1), Ir(1)–N(2) 2.083(2), N(1)–C(2) 1.292(6); C(1)–Ir(1)–N(1) 77.9(1),
◦
˚
N(1)–Ir(1)–N(2) 87.0(5), C(1)–Ir(1)–N(2) 88.5(5). (c) Complex cation of 3c. Selected bond lengths (A) and angles ( ): Ir(1)–C(1) 2.070(2), Ir(1)–N(1)
2.068(6), Ir(1)–N(2) 2.113(1), N(1)–C(2) 1.257(3); C(1)–Ir(1)–N(1) 78.8(6), N(1)–Ir(1)–N(2) 87.1(6), C(1)–Ir(1)–N(2) 86.0(8). (d) Complex cation of 3c¢
(C: gray, N: blue gray, O: red, Rh: turquoise). Selected bond lengths (A) and angles ( ): Rh(1)–C(1) 2.022(9), Rh(1)–N(1) 2.078(3), Rh(1)–N(2) 2.095(6),
◦
˚
N(1)–C(2) 1.272(5); C(1)–Rh(1)–N(1) 78.4(3), N(1)–Rh(1)–N(2) 90.2(9), C(1)–Rh(1)–N(2) 87.1(5).
Scheme 5 Synthesis of 4a and 4b.
˚
˚
8.4 and 7.0 A for the Ir ◊ ◊ ◊ Ir non-bonding distances. Different
groups, with a distance of 2.60 A between the O atom in OTf
from those in the binuclear species, the Cp* groups in the crystal
structure of 4a faced inward and partially filled one side of the
macrocycle, so forming a half-open cavity in which two OTf ions
were encapsulated. Guest ion A was surrounded by four Cp*
ion and H atom in the nearest methyl group of Cp*, indicating a
weak intermolecular hydrogen bond. The other guest ion B was
in between two bis-imine fragments. The middle phenyl groups of
the bis-imine fragments were facing the guest ion, with a distance
4986 | Dalton Trans., 2011, 40, 4982–4993
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
◦
˚
Fig. 7 (a) Side views of complex cation of 4a (C: gray, N: blue gray, O: red, F: pink, S: yellow, Ir: blue). Selected bond lengths (A) and angles ( ): Ir(1)–C(1)
2.043(9), Ir(1)–N(1) 2.120(5), Ir(1)–N(2) 2.123(3), N(1)–C(2) 1.277(4); C(1)–Ir(1)–N(1) 77.9(4), N(1)–Ir(1)–N(2) 88.4(9), C(1)–Ir(1)–N(2) 84.1(5). (b) Top
view of the complex cation of 4a.
˚
of 3.45 A between the centre of one phenyl group and F atoms
indicated, as no splitting for the four CH N groups were found
in their NMR spectra.
˚
of guest ion, and 3.57 A between the centre of the other phenyl
group and O atoms of OTf ion.
A proposed two-side attack is proposed for the existence of
isomers for 3a–3e and 3a¢–3c¢. After the dissociation of M–
Cl bonds in the binuclear complex, the metal centres could be
attacked by the N atom of pyrazine from either side of the planar
bis-imine substrate. Therefore, when metal centre A and B from
two different binuclear fragments were connected by the bridging
ligand, the configuration of them could be the same or different, as
a consequence of the two-side attack (Fig. 10a). The configurations
of A¢ and B¢—the other metal atoms of each binuclear complex—
were determined by those of metal centre A and B, because of
the rigid structure of L1–L5. Thus, two isomers were formed
and could not transform easily, since the transformation of
configurations requires the breaking of two relatively robust Ir–
N/Rh–N bonds at the same time, which was unlikely to happen
(Fig. 10b).
This explanation is supported by our group’s previous results,9,16
in which no tetranuclear macrocycles showed similar evidence
of isomers. This might be owing to the reasons below: (i) the
highly symmetrical structure of the binuclear building blocks will
not give different configurations with pyrazine attack the metal
centres from different sides,9a,b and (ii) the relatively weak M–O
bonds might be easily broken, allowing the facile transformation
of different configurations. It is noticeable that M–C bond cannot
guarantee the existence of isomers, for one of our group’s re-
ported terephthalic-acid-cyclometalated macrocycles also showed
no evidence of isomers16 and may indicate that the existence
of M–O bonds was one of the key factors for the absence of
isomers.
Solution behaviour of bis-imine-containing tetranuclear
macrocycles
One obvious feature about the bis-imine activated macrocycles
was the robust bonding of metal centres and organic lig-
ands/substrates. Hence these cyclometalation-containing macro-
cycles show higher structural stability compared with those
containing Ir–O or Rh–O bonds reported previously by us and
other groups.3–8 Observations were performed to elucidate effects
of stabilities on solution behaviours.
The 1H NMR spectra of 3a–3e and 3a¢–3c¢ (Fig. 8a shows
the example of 3e) showed equal splitting of all the peaks when
using CDCl3 as solvent. Further investigations were employed
for 3e (3e was chosen because it gives the simplest 1H NMR
spectrum), and demonstrated that the phenomenon could be
explained by existence of isomer pairs in a ratio of 1 : 1. One of
the isomers had a poor solubility in CH3OH (which is also the
reason why it was not detected and reported at the first place:10
this isomer is barely detectable by 1H NMR when using CD3OD
as solvent) but had a good solubility in CHCl3; the other one, on
the contrary, had a much poorer solubility in CHCl3 and a better
one in CH3OH. Separations of the two isomers were realized by
repeated recrystallization from CHCl3. In the 1H NMR spectra of
the separated isomers, no division of any peaks occurred. It was
worth noting that a high energy barrier between those pairs of
isomers was indicated since no sign of in-solution transformation
between isomers was detected, even after days of heating in 40 ◦C.
Significant change of chemical shift in the 1H NMR spectra of the
separated isomers were found when using CDCl3 and CD3OD as
solvent, respectively (Fig. 8b), due to the difference of polarities
of solvents.
Rigidity should also be considered to explain why no isomers
were present for 4a and 4b. The binuclear building blocks of
them exhibited free rotation axes, so that the determination of one
metal centre’s configuration had no effect on the other. Therefore,
one favorable configuration of the macrocyclic structure could be
obtained from the stepwise transformation of each metal centre,
which only required the cleavage of one Ir–N/Rh–N bond. Steric
hindrance or template effect of guest ions might also be a driving
However, for the cases of 4a and 4b, no sign of isomers was
observed in 1H NMR (Fig. 9). Highly symmetrical structures were
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4982–4993 | 4987
©

View Article Online
Fig. 8 (a) 1H NMR spectrum of isomers of 3e in CDCl3, blue and red spots correspond to the two different isomers as determined by NMR of separated
isomers. (b) 1H NMR spectra of a separated isomer of 3e in CDCl3 and CD3OD as solvent.
Fig. 9 (a) 1H NMR spectrum of 6a in CDCl3 and (b) 1H NMR spectrum of 7 in CD3OD.
4988 | Dalton Trans., 2011, 40, 4982–4993
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
Fig. 10 (a) Proposed two-side attack process and (b) proposed structures of tetranuclear isomers.
force, as indicated by the crystal structure of 4a. An increase of Synthesis of bis-imine ligand L1–L7
flexibility should also aid a favorable configuration to be obtained.
The bis-imine ligands L1–L7 were prepared from a modified
method of literature procedures.11 Corresponding aldehydes and
amines were reacted in a ratio of 1 : 2 in chloroform overnight at
room temperature. Solid products were obtained after the removal
Conclusion
1
of solvent, an after washing in CH3OH several times. H NMR
spectra were consistent with reported ones for L1,11a L2,11b L3,11b
Stepwise constructions of bis-imine-cyclometalated macrocycles
were investigated. The synthetic route was established for various
substrates (L1–L7) and metal fragments (Cp*Ir or Cp*Rh). The
structures of binuclear complexes and tetranuclear macrocycles
were confirmed by single-crystal X-ray diffraction. Isomers were
found both in binuclear species and macrocyclic complexes. More
flexible substrates led to the existence of isomers of binuclear
species, yet gave no isomers after macrocyclic construction; rigid
substrates, in contrast, led to isomers only for macrocyclic species.
The isomers of tetranuclear macrocycles were thermodynamically
stable to reversible transformation on a scale of days. Robust
bonding and a degree of rigidity were proposed as requirements for
the existence of isomers. This is the first example, to our knowledge,
that coordinate macrocycles containing half-sandwich Cp*M (M =
Ir, Rh) fragments were constructed, without showing a dynamic
reversible process. The results may help in understanding the
influence of M–C bonds on the solution behaviour of coordinate
macrocycles, while and the stability of this type of bis-imine-
cyclometaled macrocycle may benefit future researches, such as
in controllable release of guest molecules.
L511a and L6.11c
1
L1: Yellow, yield: 88%. H NMR (400 MHz, CDCl3, ppm) d
8.42 (s, 2H, HC N); 8.10 (s, 4H); 7.57 (d, 4H); 7.42 (m, 4H); 7.30
(m, 2H).
1
L2: Yellow, yield: 90%. H NMR (400 MHz, CDCl3, ppm) d
8.54 (s, 2H, HC N); 8.00 (s, 4H); 7.27 (d, 4H); 6.95 (d, 4H); 3.86
(s, 6H, OMe).
1
L3: Yellow, yield: 93%. H NMR (400 MHz, CDCl3, ppm) d
8.53 (s, 2H, HC N); 8.00 (s, 4H); 7.19 (m, 8H); 2.38 (s, 6H, Me).
1
L4: Yellow, yield: 91%. H NMR (400 MHz, CDCl3, ppm) d
8.50 (s, 2H, HC N); 8.01 (s, 4H); 7.36 (d, 4H); 7.20 (d, 4H).
L5: Pale yellow, yield: 90%. 1H NMR (400 MHz, CDCl3, ppm)
d 8.26 (s, 2H, HC N); 7.71 (s, 4H, C6H4); 3.50 (s, 6H, Me).
1
L6: Yellow, yield: 82%. H NMR (400 MHz, CDCl3, ppm) d
8.63 (s, 2H, HC N); 7.94 (m, 4H); 7.50 (m, 6H); 7.33 (s, 4H).
1
L7: Yellow, yield: 92%. H NMR (400 MHz, CDCl3, ppm) d
8.45 (s, 2H, HC N); 7.86 (d, 4H); 7.25 (d, 4H); 6.99 (d, 4H); 3.86
(s, 6H, OMe).
Preparation of binuclear complexes 1a–1e and 1a¢–1c¢
A mixture of [Cp*MCl2]2 (0.1 mmol, M = Ir, Rh), NaOAc (0.6
mmol), and corresponding substrates L1–L5 (0.1 mmol) was
stirred at 40 ◦C in 20 mL of dichloromethane for 8–18 h. The
mixture was filtered and evaporated to afford black/dark red solids
which were further purified by silica gel column chromatography
(CH2Cl2–EA = 95 : 5) to afford pure cyclometalated compounds
in yields of 70–78%.
Experimental
General procedures and materials
All reactions and manipulations were performed under a nitrogen
atmosphere, using standard Schlenk techniques. However, once
the reactions were completed, subsequent work-ups were done
without precaution, as the compounds are air-stable. Solvents
were purified by standard methods prior to use. [Cp*IrCl2]2 was
prepared according to the reported procedures.17 1H NMR spectra
were measured on a VAVCE-DMX 400 Spectrometer in CD3OD
or CDCl3. Elemental analysis was performed on Elementar vario
EL III Analyzer. IR (KBr) spectra were recorded on the Nicolet
FT-IR spectrophotometer.
1a: Black, 13 h, yield: 76%. Anal. Calc. for C40H44Cl2Ir2N2: C
47.66, H 4.40, N 2.78. Found: C 47.58, H 4.37, N 2.83%. 1H NMR
(400 MHz, CDCl3, ppm): d 8.42 (s, 2H, HC N); 8.10 (s, 2H); 7.58
(d, 4H); 7.42 (m, 4H); 7.31 (m, 2H); 1.45 (s, 30H, C5Me5). 13C NMR
(CDCl3, ppm): d 175.78 (Ir–C), 159.60 (HC N), 152.03, 151.50,
135.38, 128.97, 127.35, 122.60, 88.97 (C5Me5), 8.85 (C5Me5). IR
(KBr): nC = 1551 cm-1.
N
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4982–4993 | 4989
©

View Article Online
1b: Dark red, 12 h, yield: 75%. Anal. Calc. for C42H48Cl2Ir2N2O2:
1
C 47.23, H 4.53, N 2.62. Found: C 47.16, H 4.24, N 2.72%. H
NMR (400 MHz, CDCl3, ppm): d 8.36 (s, 2H, HC N); 8.06 (s,
2H); 7.52 (d, 4H); 6.92 (d, 4H); 3.86 (s, 6H, OMe); 1.46 (s, 30H,
C5Me5). 13C NMR (400 MHz, CDCl3–CD3OD 4 : 1, 50 ◦C): d
174.86 (Ir–C), 158.99 (HC N), 158.74, 151.37, 145.28, 135.03,
123.46, 113.85, 88.88 (C5Me5), 55.39 (OMe), 8.58 (C5Me5). IR
(KBr): nC = 1534 cm-1.
N
1c: Dark red, 12 h, yield: 78%. Anal. Calc. for C42H48Cl2Ir2N2:
1
C 48.68, H 4.67, N 2.70. Found: C 48.45, H 4.39, N 2.83%. H
NMR (400 MHz, CDCl3, ppm): d 8.37 (s, 2H, HC N); 8.07 (s,
2H); 7.45 (d, 4H); 7.20 (d, 4H); 2.41 (s, 6H, Me); 1.48 (s, 30H,
C5Me5). IR (KBr): nC = 1560 cm-1.
N
1d: Black, 18 h, yield: 70%. Anal. Calc. for C40H42Cl4Ir2N2: C
44.61, H 3.93, N 2.60. Found: C 44.29, H 3.57, N 2.66%. 1H NMR
(400 MHz, CDCl3, ppm): d 8.39 (s, 2H, HC N); 8.10 (s, 2H);
7.54 (d, 4H); 7.40 (d, 4H); 1.50 (s, 30H, C5Me5). IR (KBr): nC
=
N
1556 cm-1.
1e: Dark red, 8 h, yield: 78%. Anal. Calc. for C30H40Cl2Ir2N2:
1
C 40.76, H 4.56, N 3.17. Found: C 40.39, H 4.77, N 3.26%. H
NMR (400 MHz, CDCl3, ppm): d 8.31 (s, 2H, HC N); 7.88 (s,
2H); 3.91 (t, 6H); 1.71 (s, 30H, C5Me5). IR (KBr): nC = 1560
N
cm-1.
1a¢: Dark red, 18 h, yield: 71%. Anal. Calc. for C40H44Cl2Rh2N2:
1
C 57.92, H 5.35, N 3.38. Found: C 57.58, H 5.37, N 3.23%. H
NMR (400 MHz, CDCl3, ppm): d 8.42 (s, 2H, HC N); 8.10 (s,
2H); 7.58 (d, 4H); 7.42 (m, 4H); 7.31 (m, 2H); 1.45 (s, 30H, C5Me5).
IR (KBr): nC = 1550 cm-1.
N
1b¢: Dark red, 12 h, yield: 68%. Anal. Calc. for
C42H48Cl2Rh2N2O2: C 56.71, H 5.44, N 3.15. Found: C 56.66,
1
H 5.24, N 3.12%. H NMR (400 MHz, CDCl3, ppm): d 8.36 (s,
2H, HC N); 8.04 (s, 2H); 7.50 (d, 4H); 6.90 (d, 4H); 3.79 (s, 6H,
OMe); 1.50 (s, 30H, C5Me5). IR (KBr): nC = 1538 cm-1.
N
1c¢: Dark red, 12 h, yield: 72%. Anal. Calc. for C42H48Cl2Rh2N2:
C 58.82, H 5.64, N 3.27. Found: C 58.59, H 5.60, N 3.41. 1H NMR
(400 MHz, CDCl3, ppm): d 8.32 (s, 2H, HC N); 8.01 (s, 2H); 7.42
(d, 4H); 7.21 (d, 4H); 2.40 (s, 6H, Me); 1.47 (s, 30H, C5Me5). IR
(KBr): nC = 1561 cm-1.
N
Preparation of binuclear complexes 2a and 2b
A mixture of [Cp*IrCl2]2 (0.1 mmol), NaOAc (0.6 mmol), and
corresponding substrates L6 or L7 (0.1 mmol) was stirred at 40 ◦C
in 20 mL of dichloromethane for 8–10 h. The mixture was filtered
and evaporated to afford red solids which were further purified by
silica gel column chromatography (CH2Cl2–EA = 98 : 2) to afford
isomers of cyclometalated compounds in yields of 82–92%.
2a: Red, 10 h, yield: 82%. Anal. Calc. for C40H44Cl2Ir2N2: C
47.66, H 4.40, N 2.78. Found: C 47.37, H 4.25, N 2.71%. 1H NMR
(400 MHz, CDCl3, ppm): d 8.52 (d, 2H, HC N); 8.28 (m, 2H);
7.92 (m, 2H); 7.53–7.73 (m, 4H); 7.29 (m, 2H); 7.10 (m, 2H); 1.44
(d, 30H, C5Me5). IR (KBr): nC = 1586 cm-1.
N
2b: Red, 8 h, yield: 92%. Anal. Calc. for C42H48Cl2Ir2N2O2: C
1
47.23, H 4.53, N 2.62. Found: C 47.36, H 4.26, N 2.52%. H
NMR (400 MHz, CDCl3, ppm): d 8.22, 8.25 (d, 2H, HC N);
7.06–7.63 (m, 6H); 7.39 (d, 2H); 6.61–6.64 (m, 2H); 3.93 (d, 6H,
OMe); 1.51 (d, 30H, C5Me5). 13C-NMR (CDCl3, ppm): d 174.00,
173.68 (Ir–C); 162.77, 162.73 (HC N); 150.56, 150.53; 140.54,
140.47; 131.54, 131.47; 123.25, 123.22; 108.96, 108.94; 89.15, 89.04
4990 | Dalton Trans., 2011, 40, 4982–4993
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
(C5Me5); 55.17 (OMe); 9.01, 8.94 (C5Me5). IR (KBr): nC N = 1588
3e: yields: 56% (route A), 70% (routed B). Anal. Calc. for
C72H88F12Ir4N8O12S4: C 36.29, H 3.72, N 4.70. Found C 36.11,
H, 3.70, N 4.58%. 1H NMR (400 MHz, CD3OD, ppm): d 8.67 (s,
4H, HC N); 8.11 (s, 8H, pyrazine); 7.84 (s, 4H, Ph); 4.02 (s, 12H,
Me); 1.69 (s, 60H, C5Me5). 1H NMR (400 MHz, CDCl3, ppm): d
8.59 (s, 4H, HC N in isomer A); 8.48 (s, 4H, HC N in isomer B);
8.43 (s, 8H, pyrazine in isomer B); 8.12 (s, 8H, pyrazine in isomer
A); 4.06 (s, 12H, Me in isomer B); 3.87 (s, 12H, Me in isomer A);
1.73 (60H, C5Me5 in isomer A); 1.65 (60H, (60H, C5Me5 in isomer
cm-1.
Preparation of tetranuclear complexes 3a–3e and 3a¢–3c¢
Route A. Pyrazine (0.1 mmol) was added to a suspension
of [Cp*MCl2]2 (0.1 mmol, M = Ir, Rh) in CH3OH at room
temperature and stirred for 5 h. Ag(CF3SO3) (0.4 mmol) was added
to the resulting yellow precipitate and stirred for 2 h. NaOAc (0.6
mmol) and corresponding substrate L1–L5 (0.1 mmol) were added
and kept stirring for an additional 12 h. Solvent was removed in
vacuum, and the residue was extracted with CH2Cl2. Further pu-
rification by silica gel column chromatography (CH2Cl2–CH3OH =
9 : 1) afforded isomers of tetranuclear complexes as a red solids in
yields of 54–58%.
B). IR (KBr): nC = 1536 cm-1.
N
3a¢: yields: 54% (route A), 62% (route B). Anal. Calc. for
C92H96F12Rh4N8O12S4: C 48.60, H 4.26, N 4.93. Found: C 48.81, H
4.59, N 4.79%. 1H NMR (400 MHz, CD3OD, ppm): d 8.88 (d, 4H,
HC N); 8.25 (s, 8H, pyrazine); 8.20 (d, 4H, Ar–H); 7.48–7.53 (m,
12H, Ph); 7.21–7.33 (m, 8H, Ph); 1.60 (s, 60H, C5Me5). 1H NMR
(400 MHz, CDCl3, ppm): d 8.78 (s, 4H, HC N); 8.67 (s, 4H,
HC N); 8.54 (s, 8H, pyrazine); 8.25 (s, 8H, pyrazine); 7.30–7.12
(m, 40H, Ph); 1.51–1.48 (d, 120H, C5Me5). IR (KBr): nC N = 1556
cm-1.
Route B. Ag(CF3SO3) (51 mg, 0.2 mmol) was added to
a solution of the corresponding binuclear complex 1a–1e or
1a¢–1c¢ (0.1 mmol) in CH3OH (20 mL) at room temperature
and stirred for 3 h, followed by filtration to remove insoluble
materials. Pyrazine (0.1 mmol) was added to the filtrate and
stirred for 12 h. The solvent was removed, and the residue was
extracted with CH2Cl2. Further purification by silica gel column
chromatography (CH2Cl2–CH3OH = 9 : 1) afforded isomers of
tetranuclear complexes as a red solid in yields of 60–72%.
3b¢: yields: 53% (route A), 63% (route B). Anal. Calc. for
C96H104F12Rh4N8O16S4: C 48.17, H 4.38, N 4.68. Found: C 48.10,
1
H 4.30, N 4.53%. H NMR (400 MHz, CDCl3, ppm): d 8.63 (s,
4H, HC N); 8.41 (s, 8H, pyrazine); 8.11 (d, 4H, Ar–H); 7.36
(d, 8H, Ar–H); 7.11 (d, 8H, Ar–H); 3.93 (s, 12H, OCH3); 1.50 (s,
1
3a: yields: 56% (route A), 72% (route B). Anal. Calc. for
C92H96F12Ir4N8O12S4: C 42.00, H 3.68, N 4.26. Found: C 41.82,
H 3.63, N 4.09%. 1H NMR (400 MHz, CD3OD, ppm): d 8.86 (d,
4H, HC N); 8.29 (s, 8H, pyrazine); 8.24 (d, 4H, Ar–H); 7.49–
7.58 (m, 12H, Ph); 7.28–7.30 (m, 8H, Ph); 1.52 (s, 60H, C5Me5).
1H NMR (400 MHz, CDCl3, ppm): d 8.79 (s, 4H, HC N); 8.69
(s, 4H, HC N); 8.56 (s, 8H, pyrazine); 8.26 (s, 8H, pyrazine);
7, 50–7.01 (m, 40H, Ph); 1.56–1.51 (d, 120H, C5Me5). IR (KBr):
60H, C5Me5). H NMR (400 MHz, CDCl3, ppm): d 8.58 (s, 4H,
HC N); 8. 48 (s, 4H, HC N); 8.40 (d, 16H, pyrazine); 8.18–7.16
(m, 40H, Ar–H); 3.90–3.81 (d, 24H, OCH3); 1.57–1.56 (d, 120H,
C5Me5). IR (KBr): nC = 1556 cm-1.
N
3c¢: yields: 58% (route A), 60% (routed B). Anal. Calc. for
C96H104F12Rh4N8O12S4: C 49.49, H 4.50, N 4.81. Found: C 49.40,
1
H 4.72, N 4.76%. H NMR (400 MHz, CDCl3, ppm): d 8.69 (s,
4H, HC N); 8.40 (s, 8H, pyrazine); 8.25 (d, 4H, Ar–H); 7.28
nC = 1555 cm-1.
(d, 8H, Ar–H); 7.00 (d, 8H, Ar–H); 2.41 (s, 12H, CH3); 1.54 (s,
N
1
3b: yields: 58% (route A), 75% (routed B). Anal. Calc. for
60H, C5Me5). H NMR (400 MHz, CDCl3, ppm): d 8.60 (s, 4H,
C96H104F12Ir4N8O16S4: C 41.91, H 3.81, N 4.07. Found: C 41.78,
H 3.54, N 4.33%. H NMR (400 MHz, CDCl3, ppm): d 8.62 (s,
4H, HC N); 8.40 (s, 8H, pyrazine); 8.14 (d, 4H, Ar–H); 7.36
HC N); 8.41 (s, 4H, HC N); 8.40–8.35 (d, 16H, pyrazine); 8.18–
1
7.11 (m, 40H, Ar–H); 2.40–2.39 (d, 24H, OCH3); 1.56 (d, 120H,
C5Me5). IR (KBr): nC = 1531 cm-1.
N
(d, 8H, Ar–H); 7.14 (d, 8H, Ar–H); 3.91 (s, 12H, OCH3); 1.57
1
(s, 60H, C5Me5). H NMR (400 MHz, CDCl3, ppm): d 8.60 (s,
4H, HC N); 8. 51 (s, 4H, HC N); 8.47–8.44 (d, 16H, pyrazine);
Preparation of tetranuclear complexes 4a and 4b
8.20–7.11 (m, 40H, Ar–H); 3.90–3.82 (d, 24H, OCH3); 1.57–1.56
(d, 120H, C5Me5). IR (KBr): nC = 1556 cm-1.
Ag(CF3SO3) (0.2 mmol) was added to a solution of corresponding
binuclear complex 2a and 2b (0.1 mmol) in CH3OH (20 mL) at
room temperature and stirred for 3 h, followed by filtration to
remove insoluble materials. Pyrazine (0.1 mmol) was added to the
filtrate and stirred for 12 h. The solvent was removed and the
residue was extracted with CH2Cl2. Further purification by silica
gel column chromatography (CH2Cl2–CH3OH = 9 : 1) afforded
pure tetranuclear complexes as red solids in yields of 75–78%.
4a: Red, yield: 75%. Anal. Calc. for C92H96F12Ir4N8O12S4: C
42.00, H 3.68, N 4.26. Found: C 41.79, H 3.31, N 4.17%. 1H NMR
(400 MHz, CD3OD, ppm): d 8.56 (s, 4H, HC N); 8.44 (s, 8H,
pyrazine); 7.89 (m, 4H, Ar–H); 7.89 (m, 8H, Ar–H); 7.56 (d, 4H,
Ar–H); 7.37 (m, 4H, Ar–H); 7.00–7.05 (m, 4H, Ar–H); 1.29 (s,
N
3c: yields: 54% (route A), 63% (routed B). Anal. Calc. for
C96H104F12Ir4N8O12S4: C 42.91, H 3.90, N 4.17. Found: C 42.73,
1
H 3.71, N 4.26%. H NMR (400 MHz, CDCl3, ppm): d 8.69 (s,
4H, HC N); 8.43 (s, 8H, pyrazine); 8.28 (d, 4H, Ar–H); 7.39
(d, 8H, Ar–H); 7.06 (d, 8H, Ar–H); 2.42 (s, 12H, CH3); 1.54 (s,
1
60H, C5Me5). H NMR (400 MHz, CDCl3, ppm): d 8.63 (s, 4H,
HC N); 8.49 (s, 4H, HC N); 8.44–8.40 (d, 16H, pyrazine); 8.19–
7.10 (m, 40H, Ar–H); 2.41–2.39 (d, 24H, OCH3); 1.56 (d, 120H,
C5Me5). IR (KBr): nC = 1555 cm-1.
N
3d: yields: 54% (route A), 60% (routed B). Anal. Calc. for
C92H92Cl4F12Ir4N8O12S4: C 39.91, H 3.35, N 4.05. Found: C 39.65,
H 3.04, N 4.02%. 1H NMR (400 MHz, CD3OD, ppm): d 8.75 (s,
4H, HC N); 8.13–8.15 (m, 12H, pyrazine and Ar–H); 7.49 (d,
8H, Ar–H); 7.22 (d, 8H, Ar–H); 1.57 (s, 60H, C5Me5). 1H NMR
(400 MHz, CDCl3, ppm): d 8.55 (s, 4H, HC N); 8. 42 (s, 4H,
HC N); 8.13–7.13 (m, 56H, pyrazine and Ar–H); 1.59–1.56 (d,
1
60H, C5Me5). H NMR (400 MHz, CDCl3, ppm): d 8.60 (s, 4H,
HC N); 8.24 (s, 8H, pyrazine); 7.83–7.81 (d, 4H, Ph); 7.58–7.56
(d, 4H, Ph); 7.40–7.38 (d, 8H, Ph); 7.17–6.98 (m, 8H, Ph); 6.70–
6.67 (d, 8H, Ph); 1.26 (s, 60H, C5Me5). IR (KBr): nC = 1584
N
120H, C5Me5). IR (KBr): nC = 1551 cm-1.
cm-1.
N
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4982–4993 | 4991
©

View Article Online
4b: Red, yield: 78%. Anal. Calc. for C96H104F12Ir4N8O16S4: C
41.91, H 3.81, N 4.07. Found: C 41.63, H 3.66, N 3.98%. 1H NMR
(400 MHz, CD3CN, ppm): d 8.83 (s, 4H, HC N); 8.63 (s, 8H,
pyrazine); 8.55 (m, 4H, Ar–H); 7.82 (d, 4H, Ar–H); 7.60 (d, 4H,
Ar–H); 7.73 (m, 4H, Ar–H); 6.86 (m, 4H, Ar–H); 3.98 (s, 12H,
OCH3); 1.60 (s, 60H, C5Me5). 1H NMR (400 MHz, CDCl3, ppm):
d 8.75 (s, 4H, HC N); 8.42 (s, 8H, pyrazine); 8.16–7.59 (m, 8H,
Ph); 7.36–7.35 (d, 8H, Ph); 7.11–6.68 (m, 12H, Ph); 1.43 (s, 60H,
least-squares restraints were used, which corresponding to six
thermal parameters of C46 and two bond distances of S2–C46.
The cell contents (C368H392N32O52F48S16Ir16) include the atoms in
the absence of two triflate anions.
In all complexes, hydrogen atoms which could be found were
placed in geometrically calculated positions with fixed isotropic
thermal parameters.
C5Me5).IR (KBr): nC = 1586 cm-1.
N
Acknowledgements
This work was supported by the National Science Foundation of
China (20721063), Shanghai Science and Technology Committee
(08DZ2270500, 08DJ1400103), Shanghai Leading Academic Dis-
cipline Project (B108), and the National Basic Research Program
of China (2009CB825300, 2010DFA41160).
X-Ray crystallography
All single crystals were obtained from slow diffusion of hexane
or diethyl ether into CH2Cl2 or CH3OH solutions of the cor-
responding compounds. All the determinations of unit cell and
intensity data were performed with graphite-monochromated Mo-
˚
Ka radiation (l = 0.71073 A). All the data were collected at room
References
temperature using the w scan technique. These structures were
solved by direct methods, using Fourier techniques, and refined
on F2 by a full-matrix least-squares method. All the calculations
were carried out with the SHELXTL18 program.
1 For reviews, see: (a) D. L. Caulder and K. N. Raymond, Acc. Chem.
Res., 1999, 32, 975; (b) G. F. Swiegers and T. J. Malefetse, Chem. Rev.,
2000, 100, 3483; (c) F. A. Cotton, C. Lin and C. A. Murillo, Acc. Chem.
Res., 2001, 34, 759; (d) B. J. Holliday and C. A. Mirkin, Angew. Chem.,
Int. Ed., 2001, 40, 2022; (e) C. H. M. Amijs, G. P. M. van Klink and G.
van Koten, Dalton Trans., 2006, 308; (f) J. L. Boyer, M. L. Kuhlman and
T. B. Rauchfuss, Acc. Chem. Res., 2007, 40, 233; (g) B. H. Northrop, H.-
B. Yang and P. J. Stang, Chem. Commun., 2008, 5896; (h) E. Zangrando,
M. Casanova and E. Alessio, Chem. Rev., 2008, 108, 4979; (i) S. J. Lee
and W. Lin, Acc. Chem. Res., 2008, 41, 521; (j) M. Yoshizawa, J. K.
Klosterman and M. Fujita, Angew. Chem., Int. Ed., 2009, 48, 3418.
2 Selected examples include: (a) M. M. Olmstead, M. F. Maestre and R.
H. Fish, J. Am. Chem. Soc., 1992, 114, 10647; (b) K. K. Klausmeyer,
S. R. Wilson and T. B. Rauchfuss, J. Am. Chem. Soc., 1999, 121, 2705;
(c) K. Yamanari, S. Yamamoto, R. Ito, Y. Kushi, A. Fuyuhiro, N.
Kubota, T. Fukuo and R. Arakawa, Angew. Chem., Int. Ed., 2001, 40,
2268; (d) P. H. Dinolfo and J. T. Hupp, Chem. Mater., 2001, 13, 3113;
(e) Y. Yamamoto, H. Suzuki, N. Tajima and K. Tatsumi, Chem.–Eur.
J., 2002, 8, 4734; (f) V. Blanco, M. Chas, D. Abella, C. Peinador and
J. M. Quintela, J. Am. Chem. Soc., 2007, 129, 13978; (g) R.-T. Liao,
W.-C. Yang, P. Thanasekaran, C.-C. Tsai, M. Sathiyendiran, Y.-H. Liu,
T. Rajendran, H.-M. Lin, T.-W. Tseng and K.-L. Lu, Chem. Commun.,
2008, 3175; (h) A. Rit, T. Pape and F. E. Hahn, J. Am. Chem. Soc.,
2010, 132, 4572.
The pentamethylcyclopentadienyl ligand of complex 2a was
strongly disordered because of rotation at room temperature,
and it was also refined to two idealized positions (68 : 32). The
120 thermal parameters of 20 atoms, (C11–C20/C11¢–C20¢), were
restrained. Some unknown solvents are strongly disordered and
cannot be refined properly, as a result, the SQUEEZE19 algorithm
was used to omit all of these disordered fragments.
In complex 2b, two restraints were used to restrain both bond
distance of C22–Cl2 and angle distance of Cl2 Cl2_#1 (symmetry
code #1: 2 - x, y, 3/2 - z).
In complex 3a, all atoms of the two triflate anions were refined
isotropically because of non-positive definition and other non-
hydrogen atoms were refined anisotropically. Two of the four
triflate anions and some unknown solvents are strongly disordered
and cannot be refined properly, as a result, the SQUEEZE19
algorithm was used to omit all of these disordered fragments.
Three pairs of atoms (O2, S1, F2, and O2¢ S1¢, F2¢) with C45/S1
triflate anion and all O and F atoms with C46/S2 were treated
using a disorder mode. All 67 restraints were used to restrain the
geometry of both triflate anions (C45/S1, C45¢/S1¢ and C46/S2)
to get better results.
Because the diffraction points are not very high quality and
there is some trailing, the error of refinement of complex 3b is
slightly larger, as a result, the reported parameters on the unit cell
axes are also large.
In complex 3c, the bond distance of C47–F2 was restrained so
that the geometry of the triflate anion was improved, the thermal
ellipsoids of atom N1 was restrained, 13 least-squares restraints
were used, of which 12 thermal parameters of C47 and N1, and one
bond distance C47–F2 were restrained. Some unknown solvents
are strongly disordered and cannot be refined properly, as a result,
the SQUEEZE19 algorithm was used to omit all of these disordered
fragments.
In the asymmetric unit of complex 4a, two of the four triflate
anions and some unknown solvents are strongly disordered and
cannot be refined properly, as a result, the SQUEEZE19 algorithm
was used to omit all of these disordered fragments. The H atoms
of the water molecule could not restrained and were deleted. Eight
3 K. Severin, Chem. Commun., 2006, 3859.
4 B. Therrien, Eur. J. Inorg. Chem., 2009, 2445.
5 Y.-F. Han, W.-G. Jia, W.-B. Yu and G.-X. Jin, Chem. Soc. Rev., 2009,
38, 3419.
6 Y.-F. Han, W.-G. Jia, Y.-J. Lin and G.-X. Jin, Angew. Chem., Int. Ed.,
2009, 48, 6.
7 (a) M.-L. Lehaire, R. Scopelliti, H. Piotrowski and K. Severin, Angew.
Chem., Int. Ed., 2002, 41, 1419; (b) G.-L. Wang, Y.-J. Lin, H. Berke and
G.-X. Jin, Inorg. Chem., 2010, 49, 2193.
8 B. Therrien, G. Su¨ss-Fink, P. Govindaswamy, A. K. Renfrew and P. J.
Dyson, Angew. Chem., Int. Ed., 2008, 47, 3773.
9 (a) Y.-F. Han, Y.-J. Lin, W.-G. Jia and G.-X. Jin, Organometallics, 2008,
27, 4088; (b) Y.-F. Han, Y.-J. Lin, W.-G. Jia, G.-L. Wang and G.-X. Jin,
Chem. Commun., 2008, 1807; (c) W.-G. Jia, Y.-F. Han, Y.-J. Lin, L.-H.
Weng and G.-X. Jin, Organometallics, 2009, 28, 3459; (d) W.-Z. Zhang,
Y.-F. Han, Y.-J. Lin and G.-X. Jin, Dalton Trans., 2009, 8426.
10 Y.-F. Han, H. Li, L.-H. Weng and G.-X. Jin, Chem. Commun., 2010,
46, 3556.
11 (a) T. Kajimoto and J. Tsuji, J. Org. Chem., 1983, 48, 1685; (b) J.
Lewkowski and M. Dziegielewski, Heteroat. Chem., 2010, 20, 431;
(c) B. J. E. Reich, A. K. Justice, B. T. Beckstead, J. H. Reibenspies
and S. A. Miller, J. Org. Chem., 2004, 69, 1357; (d) S. Sellarajah, T.
Lekishvili, C. Bowring, A. R. Thompsett, H. Rudyk, C. R. Birkett, D.
R. Brown and I. H. Gilbert, J. Med. Chem., 2004, 47, 5515.
12 D. L. Davies, O. Al-Duaij, J. Fawcett, M. Giardiello, S. T. Hilton and
D. R. Russell, Dalton Trans., 2003, 4132.
13 L. Li, W. W. Brennessel and W. D. Jones, Organometallics, 2009, 28,
3492.
4992 | Dalton Trans., 2011, 40, 4982–4993
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
14 L. Li, W. W. Brennessel and W. D. Jones, J. Am. Chem. Soc., 2008, 130,
12414.
18 G. M. Sheldrick, SHELXL-97, Universita¨t Go¨ttingen, Germany,
1997.
19 (a) P. Van Der Sluis and A. L. Spek, Acta Crystallogr., Sect. A: Found.
Crystallogr., 1990, 46, 194; (b) A. L. Spek, PLATON, A Multipurpose
Crystallographic Tool, Utrecht University, Utrecht, The Netherlands,
2005; (c) Farrugia, WINGX, 1999.
15 A. D. Ryabov, Chem. Rev., 1990, 90, 403.
16 W.-B. Yu, Y.-F. Han, Y.-J. Lin and G.-X. Jin, Organometallics, 2010,
29, 2827.
17 C. White, A. Yates and P. M. Maitles, Inorg. Synth., 1992, 29, 228.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 4982–4993 | 4993
©