Metal complexes with di(N-heterocyclic carbene) ligands bearing a rigid: Ortho -, meta or para -phenylene bridge

Article abstract of DOI:10.1039/c6dt01129b

Three novel dinuclear bis-dicarbene silver(i) complexes of general formula [Ag₂(MeIm-phenylene-MeIm)₂](PF₆)₂ (Im = imidazol-2-ylidene) were synthesized. The corresponding copper(i) and gold(i) complexes were obt

Full text of DOI:10.1039/c6dt01129b

View Article Online
View Journal
Dalton
Transactions
Accepted Manuscript
This article can be cited before page numbers have been issued, to do this please use: M. Monticelli, C.
Tubaro, M. Baron, M. Basato, P. Sgarbossa, C. Graiff, G. Accorsi, T. P. Pell, D. J. Wilson and P. Barnard,
Dalton Trans., 2016, DOI: 10.1039/C6DT01129B.
This is an Accepted Manuscript, which has been through the
Royal Society of Chemistry peer review process and has been
accepted for publication.
Accepted Manuscripts are published online shortly after
acceptance, before technical editing, formatting and proof reading.
Using this free service, authors can make their results available
to the community, in citable form, before we publish the edited
article. We will replace this Accepted Manuscript with the edited
and formatted Advance Article as soon as it is available.
You can find more information about Accepted Manuscripts in the
Information for Authors.
Please note that technical editing may introduce minor changes
to the text and/or graphics, which may alter content. The journal’s
standard Terms & Conditions and the Ethical guidelines still
apply. In no event shall the Royal Society of Chemistry be held
responsible for any errors or omissions in this Accepted Manuscript
or any consequences arising from the use of any information it
contains.
www.rsc.org/dalton

Please do not adjust margins
Dalton Transactions
Page 1 of 12
View Article Online
DOI: 10.1039/C6DT01129B
Journal Name
ARTICLE
Metal complexes with di(N‐heterocyclic carbene) ligands bearing
a rigid ortho‐, meta or para‐phenylene bridge
Received 00th January 20xx,
Accepted 00th January 20xx
Marco Monticelli,a Cristina Tubaro,*,a Marco Baron,a Marino Basato,a Paolo Sgarbossa,b Claudia
Graiff,c Gianluca Accorsi,d Thomas P. Pell,e David J. D. Wilsone and Peter J. Barnard*,e
DOI: 10.1039/x0xx00000x
Three novel dinuclear bis‐dicarbene silver(I) complexes of general formula [Ag2(MeIm‐phenylene‐MeIm)2](PF6)2 (Im =
imidazol‐2‐ylidene) were synthesized. The corresponding copper(I) and gold(I) complexes were obtained by
transmetalation of the di(N‐heterocyclic carbene) ligand from the silver(I) species, and both coordination geometry and
stoichiometry are maintained for all three group 11 metals as expected. The photophysical properties of the Ag(I) and
Au(I) complexes were also investigated and discussed; in particular the most strongly emitting complex was also studied
via DFT calculations. In addition, the ruthenium(II) and iridium(III) complexes [RuCl(MeIm‐(o‐phenylene)‐MeIm)(p‐
cym)](PF6) and [IrClCp*(MeIm‐(o‐phenylene)‐MeIm)](PF6) were prepared and shown to present in these cases a chelating
coordination of the di(N‐heterocyclic carbene) ligand.
www.rsc.org/
patterns on the phenylene ring were found to influence the
bridging versus chelating coordination properties of the
dicarbene ligands. A limited number of examples have been
Introduction
Late transition metal complexes of N‐heterocyclic carbene
(NHC) ligands1 have been intensively investigated over the last
twenty years.2 This attention results from the wide range of
possible applications of complexes of this type in catalysis,3
material science4 and bioinorganic chemistry.5 Recently there
has been much interest in the preparation and study of
luminescent NHC complexes of late transition metals6 e.g.
Cu(I),7 Ag(I),8 Au(I,III),9 Ni(II),10 Pd(II),10,11 Pt(II),10‐12 Ir(III),13
Ru(II).14 Due to the planar nature of NHCs, these donors are
well suited to the synthesis of luminescent dinuclear Au(I)
complexes that support short aurophilic Au∙∙∙Au interactions. A
number of complexes of this type with di(N‐heterocyclic
carbene) ligands (diNHC)15 and a variety of linker groups have
been reported and some of them display fascinating
luminescent properties.16‐21 Generally the di(N‐heterocyclic
carbene) ligands (diNHC) have either an alkyl chain, (CH2)n (n =
1 ‐ 4), or a ortho‐, meta‐ or para‐xylylene as bridging group
between the two carbene moieties.
previously reported in the literature with this class of ligands22‐
35 and, in most cases they involve diNHC groups with the meta‐
phenylene bridge. This choice is justified by the fact that these
ligands commonly behave as CCC‐pincers, as a consequence of
metalation of the carbon in position 2 of the phenylene bridge
(mainly to Ir(III),22,24 Ru(II)26,30 or Pt(II)19).
In the present study, a series of dinuclear silver(I) complexes of
the phenylene bridged NHC ligands were prepared from the
imidazolium salt precursors and Ag2O. The synthesis of the
corresponding gold(I) and copper(I) complexes was readily
achieved through transmetalation of the carbene ligand from
the corresponding silver(I) complexes. Finally, transmetalation
of the dicarbene ligand to iridium(III) and ruthenium(II) was
successful with the ortho‐phenylene ligand only.
Results and discussion
Synthesis of diiimidazolium salts
In this work, we extend our studies to rigid ortho‐, meta‐ and
para‐phenylene bridging groups. The different substitution
The bis(imidazol‐1‐yl)benzene precursors were prepared from
ortho‐, meta‐ or para‐dibromobenzene and imidazole, using
Cu(I) catalysed Ullmann‐type coupling procedure (Scheme 1).
The diimidazolium cations were prepared by alkylation of the
a.
Dipartimento di Scienze Chimiche, Università degli Studi di Padova, via Marzolo
1, 35131 Padova (Italy).
Dipartimento di Ingegneria Industriale, Università degli Studi di Padova, via
b.
bis(imidazole‐1‐yl)arenes
with
methyl
iodide
in
Marzolo 9, 35131 Padova (Italy).
c. Dipartimento di Chimica, Università degli Studi di Parma, Viale delle Scienze
17/A, 43100 Parma (Italy).
dimethylsulfoxide at room temperature, to give the bis‐
imidazolium diiodide salts. The solubility of these compounds
d.
was improved via anion I‐/PF6 exchange, yielding the
CNR NANOTEC ‐ Institute of Nanotechnology c/o Campus Ecotekne, University of
‐
Salento, Via Monteroni ‐ 73100 Lecce (Italy).
e. Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La
Trobe University, Victoria, 3086, Australia, Fax: (+)61 3 9479 1266.
Electronic Supplementary Information (ESI) available: Crystal data for complexes
1a (CCDC 1433307), 1a* (CCDC 1433308), 1b (CCDC 1433309), 2a (CCDC 1433310),
2b (CCDC 1433311) and 5a (CCDC 1433312). See DOI: 10.1039/x0xx00000x
bis(hexafluorophosphate) salts. The same or analogous (with
different nitrogen substituents) diimidazolium cationic
compounds were already reported in the literature, and the
synthesis involved a very similar two‐step procedure.22‐35
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 1
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 2 of 12
ARTICLE
Journal Name
crystallographically independent but very similar cationic
View Article Online
‐
DOI: 10.1039/C6DT01129B
complexes and four PF6 anions are present. The ORTEP views
of one of the two cationic moieties in complex 1a and the
cation in 1b are reported in Figure 1 and Figure 2 respectively
together with the atomic labelling scheme; a list of the most
important bond distances and angles is collected in the
captions. Cationic complexes in 1a as well as in 1b are
dinuclear with two dicarbene ligands bridging the two silver
atoms. In 1a the bridging ligands form a 14‐membered ring
while in 1b the meta isomers of the bridging phenylene cause
the formation of a 16‐membered ring. The conformation of the
two complexes is different, with the cationic moiety of 1b
being centrosymmetric with the inversion center located in the
middle of the 16‐membered ring thus forcing an ‘anti’
conformation, while the 14‐membered ring in the cationic
moiety of 1a shows a ‘syn’ conformation.38 The Ag‐Ccarbene
bond lengths span from 2.076(5) to 2.094(5) Å in 1a and from
2.086(4) to 2.092(4) Å in 1b, and fall in the typical range for
[Ag(NHC)2]+ complexes. Considering the Ccarbene‐Ag‐Ccarbene
bond angle, it deviates only slightly from linearity in the case of
complex 1b (175.16(13)°), while in the case of 1a it is more
deviated (175.8(2) and 170.7(2)° in one of the two
independent cationic moieties and 176.7(2) and 171.5(2)° in
the other). Moreover while in 1b the Ag∙∙∙Ag separation is
7.165(2) Å, in 1a the Ag∙∙∙Ag distance is 3.289(2) and 3.265(1)
in the two independent cationic moieties and this interatomic
separation is slightly shorter than the sum of the Van der
Waals radii for silver. Because of the centrosymmetry of
complex 1b, the mean planes of the phenyl rings are parallel at
a distance of 4.306(2) Å (centroid to centroid separation of
4.409(2) Å), considering the crystal packing it is evident that
Scheme 1. Preparation of diimidazolium salts. Experimental details: i) imidazole,
dibromobenzene, CuO, K2CO3, DMSO, 150 °C, 48 h. ii) MeI, DMSO, room temperature,
12 h. iii) NH4PF6 methanol.
Synthesis of group 11 metal complexes
The silver(I) di(N‐heterocyclic carbene) complexes of general
formula [Ag2(diNHC)2](PF6)2 were synthesized by reaction of
the appropriate diimidazolium bis(hexafluorophosphate) salt
with excess silver(I) oxide in acetonitrile at 65 °C for 24 hours
(Scheme 2). Initially, the synthesis of the silver complexes was
attempted using the diimidazolium diiodide salt with Ag2O in
water for 24 hours at room temperature, followed by anion I‐
‐
/PF6 metathesis. Unfortunately, with this type of procedure,
the obtained solids were not pure and contaminated by an
appreciable quantity of the starting materials, as indicated by
the presence in the 1H‐NMR spectra of the signal
corresponding to the C2‐H protons.
Complexes 1a‐c are light grey solids, soluble in common polar
organic solvents (e.g. acetonitrile and dimethylsulfoxide). The
deprotonation of the diimidazolium salt is confirmed by the
1
absence of the C2‐H signal in the H NMR spectrum of the
reaction products and the formation of the silver complexes is
supported by the presence of the carbene carbon signal in the
13C NMR spectra at δ 180‐185 ppm, in the typical range of
carbene carbons coordinated to a silver(I) center.36,37 The
dinuclear dicationic nature of the complexes with the two
dicarbene ligands bridging the two metal centers is then
further established with the ESI‐MS spectra, which show the
peaks corresponding to the [Ag2L2PF6]+, [Ag2L2]+ and [Ag2L2]2+
fragments. Analogous results have been reported by Hahn et
al. with a para‐phenylene dicarbene ligand having ethyl
instead of methyl groups, as substituents to the nitrogen
atoms in position 1.28a
··· interactions are also present between the phenyl rings of
adjacent molecules (centroid to centroid distance of 4.803(2)
Å) and between the phenyl ring and the imidazole ring of
facing molecules (centroid to centroid distance of 4.299(2) Å)
(see Figure 3).
Figure 1. ORTEP view of one of the two caationic units of complex 1a. Ellipsoids are
drawn at their 30% probability. Hydrogen atooms and PF6‐ anions have been omitted for
clarity. Selected bond distances (Å) and anggles (deg) (data in squared parentheses are
referred to the second cationic unit): C1‐AAg1 2.076(5) [2.092(5)], C28‐Ag1 2.076(5)
[2.085(5)], C14‐Ag2 2.088(5) [2.091(5)], C155‐Ag2 2.088(5) [2.094(5)], C1‐N2 1.345(7)
[1.346(6)], C5‐N2 1.430(7) [1.427(7)], C5‐CC10 1.387(8) [1.379(7)], C10‐N3 1.414(7)
[1.433(7)], C14‐N3 1.347(7) [1.356(6)], C155‐N6 1.360(6) [1.346(7)], C19‐N6 1.410(7)
[1.428(7)], C19‐C24 1.383(7) [1.390(8)], C244‐N7 1.422(7) [1.434(8)], C28‐N7 1.346(6)
Scheme 2. Synthesis of the silver(I) di(N‐heterocyclic carbene) complexes.
The crystal structures of the compounds 1a and 1b have been
fully elucidated by single crystal X‐ray diffraction analysis. The
crystals of 1a and 1b contain cationic complexes and PF6
‐
anions. In particular in the unit cell of 1a two
2 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 3 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
[1.356(7)], Ag1∙∙∙Ag2 3.289(2) [3.265(1)]; C1‐Ag1‐C28 175.8(2) [176.7(2)], C15‐Ag2‐C14
170.7(2) [171.5(2)].
Compound 1a* is a coordination cationic metallopolymer
formed by infinite chains of dimers [Ag2(CH3COO)(diNHC)]
View Article Online
DOI: 10.1039/C6DT01129B
connected by Ag∙∙∙Ag Van der Waals interactions. The
polymeric structure develops along the a axis of the cell. The
symmetric dinuclear complex, which is constructed over a
mirror m orthogonal with respect to the metal∙∙∙metal
separation, is formed by two silver atoms bridged by the
diNHC ligand and by an acetate anion. The diNHC ligand and
the metal atoms form an eight membered ring with a boat
conformation. The Ag atom is bonded to a carbene carbon
atom (C1‐Ag 2.067(4) Å), and an oxygen atom of an acetate
anion (Ag‐O2 2.111(3) Å) in a nearly linear arrangement (C1‐
Ag‐O2 176.63(14)°). The mean planes of the imidazole rings of
the bridging diNHC ligand form a dihedral angle of 64.01(2)°.
The Ag’∙∙∙Ag and Ag∙∙∙Ag’’ separations are 2.9279(8) and
3.0462(7) Å. The polymeric structure develops in a zig zag
chain with an Ag’∙∙∙Ag∙∙∙Ag’’ angle of 148.51(1)°. In the crystals
Figure 2. ORTEP view of the cationic part of complex 1b. Ellipsoids are drawn at their
30% probability. Hydrogen atoms and PF6‐ anions have been omitted for clarity.
Selected bond distances (Å) and angles (deg): C1‐Ag 2.092(4), C14’‐Ag 2.086(4), C1‐N2
1.350(5), C5‐N2 1.431(4), C5‐C6 1.392(5), C6‐C7 1.383(5), C7‐N3 1.437(4), C14‐N3
1.352(5); C14’‐Ag‐C1 175.16(13). Symmetry code for equivalent atoms: ’= 1‐x, ‐y, ‐z.
‐
of compound 1a*, PF6 anions are also present to neutralize
the positive charges. The process leading to the formation of
complex 1a* should involve the hydrolysis of acetonitrile
solvent to ammonium acetate.
Gold(I) and copper(I) complexes were synthesized via
transmetalation of the dicarbene ligand from the
corresponding silver(I) complexes (Scheme 3). The 1H‐NMR
spectra of the gold(I) complexes are similar to those of the
dinuclear silver(I) precursors, thus indicating that the
symmetric dinuclear structure is maintained upon
transmetalation of the ligand. In particular, the 1H NMR signals
of the two hydrogen atoms of the imidazole backbone and the
aromatic signals of phenylene bridge are slightly shifted
downfield in comparison with the corresponding silver(I)
complex; the same shift is observed also in the 13C NMR
spectra for the C4 and C5 carbon atoms. A different behavior is
generally observed for the carbene carbon signal, which is
slightly upfield shifted due to the higher Lewis acidity of the
gold(I) center with respect to the silver(I) one. The formation
of the dinuclear gold(I) complexes is further confirmed by the
ESI‐MS spectra, which present the peaks of the [Au2L2PF6]+ and
[Au2L2]2+ fragments, whose nature is also supported by the
simulation of the isotopic pattern.
Figure 3. Packing diagram of cationic complexes in 1b evidencing the stacking of
adjacent molecules.
Interestingly, in the crystallization process of complex 1a in
acetonitrile, very few crystals of a second species, namely 1a*
,
have been obtained. The ORTEP view of 1a* is shown in Figure
4 and a list of the most important bond distances and angles is
collected in the caption.
Figure 4. ORTEP view of the polymeric structure of complex 1a*. Ellipsoids are drawn at
their 30% probability. Hydrogen atoms have been omitted for clarity. Selected bond
distances (Å) and angles (deg): C1‐N1 1.348(5), C1‐N2 1.352(5), C1‐Ag 2.067(4), C2‐N1
1.462(5), C3‐C4 1.340(6), C3‐N1 1.378(5), C4‐N2 1.382(5), C5‐C6 1.379(5), C5‐C5’
1.383(7), C5‐N2 1.436(5), Ag‐O2 2.111(3), Ag∙∙∙Ag’ 2.9279(8), Ag∙∙∙Ag’’ 3.0462(7); N1‐C1‐
Scheme 3. Synthesis of the gold(I) and coppeer(I) di(N‐heterocyclic carbene) complexes.
N2 104.6(3), N1‐C1‐Ag 128.8(3), N2‐C1‐Ag 126.6(3), C5’‐C5‐N2 119.73(18), C1‐Ag‐O2 The dinuclear complex 2b could be also prepared by heating
176.63(14), C1‐N1‐C3 110.8(3), C1‐N1‐C2 124.1(3), C3‐N1‐C2 125.0(3), C1‐N2‐C4
111.1(3), C1‐N2‐C5 122.9(3), C4‐N2‐C5 126.0(3), C8‐O2‐Ag 126.6(3), Ag’∙∙∙Ag∙∙∙Ag’’
148.51(1). Symmetry code for equivalent atoms: ’ = ½‐x, y, z; ’’ = ‐x, 1‐y, ‐z.
the appropriate diimidazolium diiodide salt with (THT)AuCl in
the presence of a weak base like sodium acetate (Scheme 4).39
The reaction was carried out in DMF at 110 °C for 2 h, diethyl
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 3
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 4 of 12
ARTICLE
Journal Name
ether was used to fully precipitate the crude product, which been recently reported in the literature with silVvieewr(AI)rt,icgleoOlndli(nIe)
−
DOI: 10.1039/C6DT01129B
was then converted to the PF6 complex by way of anion and mercury(II) metal centers. The structure here reported for
metathesis reaction, using KPF6 in water. The NMR complex 2b (as well as for complex 1b) shows the open
characterisation of the complex obtained with this procedure conformation (i).
fully matched that of the complex obtained via trasmetalation
of the diNHC ligand.
Scheme 4. Direct synthesis of complex 2b.
The structure of complexes 2a and 2b has been further
confirmed on the basis of X‐ray crystal structure analysis. In
‐
the crystals of 2a cationic moieties, PF6 anions and acetonitrile
solvent molecules are present. The ORTEP views of the cationic
moieties in complexes 2a and 2b are reported in Figure 5 and
Figure 6 respectively together with the atomic labelling
Figure 5. ORTEP view of the cationic compplex 2a. Ellipsoids are drawn at their 30%
probability. Hydrogen atoms, PF6 anions annd acetonitrile solvent molecule have been
omitted for clarity. Selected bond distances ((Å) and angles (deg): C1‐Au 2.013(5), C1‐N2
‐
scheme; a list of the most important bond distances and
angles is collected in the captions. The cationic moieties are
dinuclear with two dicarbene ligands bridging the two gold
atoms in a very similar manner to what observed in the case of
silver. In particular in complex 2a the two bridging ligands form
a 14‐membered ring with a boat conformation. The complex is
highly symmetric, being constructed over two mutually
perpendicular mirror planes and shows a ‘syn’ conformation.38
The Au∙∙∙Au separation is 3.656(2) Å and the Au‐Ccarbene bond
distance (2.013(5) Å) is in the typical range for analogous NHC‐
Au(I) complexes. The Ccarbene‐Au‐Ccarbene bond angle shows a
slight deviation from linearity (174.1(2)°). In the crystal packing
1.363(5), C5‐N2 1.434(4), C5‐C5’’ 1.392(7); C1‐Au‐C1’’’ 174.1(2). Symmetry code for
equivalent atoms: ’ = 1‐x, y, ½‐z; ’’ = x, y, ½‐z;; ’’’ = 1‐x, y, z.
of complex 2a there is no evidence of ∙∙∙ stacking between
adjacent molecules.
Compound 2b is isostructural with the silver analogous 1b. In
the dinuclear dicationic moiety the two bridging ligands form a
symmetric 16‐membered ring, with ‘anti’ conformation. The
Au∙∙∙Au separation is 7.140(2) Å and the Ccarbene‐Au‐Ccarbene
Figure 6. ORTEP view of the cationic compplex 2b. Ellipsoids are drawn at their 30%
probability. Hydrogen atoms, PF6 anions annd acetonitrile solvent molecule have been
omitted for clarity. Selected bond distances (Å) and angles (deg): C1‐Au 2.021(5), C14’‐
Au 2.025(5), C1‐N2 1.359(6), C5‐N2 1.437(6)), C5‐C10 1.392(6), C10‐C9 1.388(6), C9‐N3
1.447(6), C14‐N3 1.343(6); C14’‐Au‐C1 175.77(2). Symmetry code for equivalent atoms:
’= ‐x, ‐y, 1‐z.
‐
bond angle shows
a
slight deviation from linearity
(175.68(16)°). The mean planes of the phenyl rings are parallel
at a distance of 4.363(2) Å (centroid to centroid separation of
4.416(2) Å). Considering the crystal packing, ∙∙∙ interactions
are also present between the phenyl rings of adjacent
molecules (centroid to centroid separation of 4.775(2) Å) and
between the phenyl ring and the imidazole ring of faced
molecules (centroid to centroid distance of 4.423(2) Å) (see
Figure 7), in a very similar way to that exhibited by the
corresponding silver complex 1b
.
In the case of di(N‐heterocyclic carbene) ligands bearing a 1,3‐
disubstituted arene linker, two possible structures are
reported in the literature: (i) open ring stretched out
conformation characterized by a long intramolecular Au∙∙∙Au
distance and by intermolecular π∙∙∙π interactions and (ii) a
twisted conformation with a short intramolecular Au∙∙∙Au
distance. Examples of both type (i)40 and type (ii)41,42 have
Figure 7. Packing diagram of cationic commplexes in 2b evidencing the stacking of
adjacent molecules.
4 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 5 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
The transmetalation route allows also the syntheses of the
copper(I) complexes 3a 3c. For example complex 3c, with
Table 1. Photophysical data of the investigated complexes in the solid state (as
View Article Online
DOI: 10.1039/C6DT01129B
powder) at room temperature.
‐
para‐phenylene bridge, shows in the NMR spectra the
expected set of signals, similar to the silver(I) analogue.
Furthermore, in the ESI‐MS spectrum, the fragments
[Cu2L2PF6]+, [Cu2L2]+ and [Cu2L2]2+ can be observed. The copper
complexes are fairly stable, even if a slight darkening of the
powder and of their acetonitrile solution is observed with time
(24‐48 h). Particular care should be taken with the copper
complex 3a, with the ortho‐phenylene diNHC, which could be
synthesized and stored only in strictly anaerobic conditions,
i.e. dry box. By exposure to air of an acetonitrile solution of
complex 3a, it quickly decomposes giving inter alia evolution
products such as [Cu(CH3CN)4]+ (evidenced by X‐ray structure
determination of few isolated crystals) and an organic
species.43 The NMR spectra of the evolved solution show the
presence of the ligand functional groups albeit at markedly
different chemical shift with respect to those observed in the
pristine complex 3a. The value of the C2 carbon resonance at
127.4 ppm, seems to rule out the possibility of coordination to
the copper(I) center.
Complex
max
(nm)a
410
420
460
380
450
478
Φ (%)a
(s)b
M∙∙∙M
distance (Å)
3.266
1a
1b
1c
2a
2b
2c
< 1%
< 1%
< 1%
1.0
5.7
2.8
c
c
7.165
‐
3.657
7.140
15.0 ‐ 234
1.1
0.4
22 ‐ 140
7.213d
a exc = 300 or 330 nm; b exc = 330 nm; c Not detected due to the weakness of the
signal. d From Ref.28
The emission spectra, reported in Figure 9, are centred in the
410 ‐ 480 nm window (blue region). The gold(I) complexes
show a discrete quantum efficiency (up to ~6% for 2b, Table 2)
while the corresponding silver(I) compounds are weak
emitters (PLQY < 1%). Both the shape profiles and the relative
lifetime decays indicate the presence of two emitting states.
For instance, the complexes 1c and 2c show broader and red‐
shifted profiles compared to those involving ligands
a and b.
Moreover, their lifetimes follow a biexponential decay and are
much longer (up to two order of magnitude) than 2a‐b
(unfortunately, the lifetimes of 1a and 1b could not be
measured because of the weakness of the signals). These
optical features suggest a Metal Centered (MC) emission for 1‐
The photophysical properties of both gold(I) and silver(I)
complexes have been investigated at room temperature in the
solid state as powder. All the excitation profiles, reported in
Figure 8 and recorded by monitoring the emission maxima, are
centered in the UV region (below 400 nm) and can be
attributed to the π–π* Ligand Centered (LC) transitions (see
further in the text).19b
2c and a predominant LC character for 1‐2a and 1‐2b 19b,42
.
In order to rationalize the dependence of the PL performances
on the geometrical factors, the aurophilic interaction model44
can be taken into account since it states the central role of the
metal‐metal distance to this regard. Unfortunately, in the
present case the samples have different emitting states (MC
and LC) and a proper correlation cannot be made for the
whole series. For example complexes 2a and 2b (M‐M distance
of 3.66 and 7.14 Å, respectively), having both LC emissive
nature, show different quantum efficiencies (1.0 and 5.7%,
respectively) suggesting that additional factors, rather than the
distance between metals, such as sample geometry and ∙∙∙
crystal stacking, influence the optical properties of the
dinuclear gold(I) complexes.
Figure 8. Excitation spectra (em = max) in the solid state as powder at 298 K. Left
window: 1a (black), 1b (red) and 1c (green). Right window: 2a (black), 2b (red) and 2c
(green).
Figure 9. Emission spectra exc = 300 or 330 nm) in the solid state as powder at 298 K.
Left window: 1a (black), 1b (red) and 1c (green). Right window: 2a (black), 2b (red) and
2c (green). For each window, the profile intensities have been normalized according to
the corresponding quantum efficiencies.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 5
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 6 of 12
ARTICLE
Journal Name
Complex 2b was found to be non‐emissive in acetonitrile
solution both at room temperature and in frozen solution at
77 K. Nonetheless, considering the interesting emitting
properties of complex 2b in the solid state, we decided to
further explore the nature of the observed Uv‐vis transitions
for this complex by performing TDDFT calculations.
The geometry of the cationic part of complex 2b was
optimised at the M06‐L/def2‐SVP level of theory, and the
results were in good agreement with the available X‐ray crystal
structure. In particular, the Au∙∙∙Au distances is ca. 0.15 Å
greater than that obtained from X‐ray crystallography, and the
near‐linear Ccarbene‐Au‐Ccarbene geometry is predicted with an
average bond angle of 174.1o, in agreement with 175.4o from
the available crystal structure.
Table 2. CAM‐B3LYP/def2‐SVP calculated absorbance transitions with acetonitrile
View Article Online
DOI: 10.1039/C6DT01129B
solvent for complex 2b.
λ (nm)
237
235
218
217
205
202
188
f
Assignment
H → L+2
H‐1→ L
H → L+4
H‐1 → L+1
H‐3 → L
H → L+3
H → L+6
0.27
0.13
0.94
0.95
0.27
1.32
0.29
ML‐LCT
ML‐LCT
LC
LC
LC
ML‐LCT
LC, LMCT
Furthermore, natural bond orbital (NBO) calculations provide
for an analysis of the electronic structure and interaction
between Au atoms. The Wiberg bond index (WBI) for the
Au∙∙∙Au interaction in the open form is 0.002‐0.005, indicative
of insignificant aurophilic interactions.45 The Au atoms are
calculated to be positively charged (NPA average of +0.26),
which results in a breaking of the formal 5d10 6s0 electronic
structure of Au(I): the electronic configuration is 5d9.61 6s1.01
6p0.12 from NBO calculations, and the small amount of
hybridization is a further confirmation of very weak (or non‐
existent) aurophilic interaction in this system. The simple van
der Waals interaction between two M+ centres may be
calculated using the London formula as
Figure 11. UV‐visible absorbance spectra from acetonitrile solution for complex 2b (3.0
× 10‐5 M).
Synthesis of Ir(III) and Ru(II) diNHC complexes
3IM M2 
The transmetalation synthetic procedure was then used with
partial success for the synthesis of dicarbene ruthenium(II) and
iridium(III) complexes. The reaction of the silver(I) complex 1a
with [IrCl2Cp*]2 or [RuCl2(p‐cymene)]2 at room temperature in
acetonitrile, using a Ag:M ratio 1:1 (M = Ir) or 1:2 (M = Ru),
affords complexes 4a and 5a respectively (Scheme 5).
In both cases monocationic complexes are obtained, in which
one di(N‐heterocyclic carbene) ligand is chelating the metal
center. The coordination sphere is completed by one chloride
ligand and by an aromatic ring (Cp* for the iridium(III) and p‐
cymene for the ruthenium(II) complex). The ESI‐MS spectra
support indeed this formulation and show the fragments
corresponding to [IrClCp*L]+ or to [RuClL(p‐cymene)]+
respectively. The coordination of the carbene ligand to the
metal center is further supported by the chemical shift of the
carbene carbon in the 13C‐NMR spectra, 157.0 for C2‐Ir and
179.5 for C2‐Ru, in the typical range of carbene carbons
coordinated respectively to an iridium(III) or ruthenium(II)
center.47
Eint

6
4 r(M  M )


1
2
where IM+ is the ionization potential (20.5 eV for Au+), M+ is
the polarizability (1.72 Å3), and r(M1‐M2) is the metal‐metal
distance. For complex 2b, Eint is 0.04 kJ/mol at the optimized
bond distance, again reflecting the small Au∙∙∙Au interaction in
the complex.46
Molecular orbital contour plots for the highest occupied
molecular orbital (HOMO) and the lowest unoccupied
molecular orbital (LUMO) of complex 2b were calculated at the
CAM‐B3LYP/def2‐SVP level of theory and are shown in Figure
10. These contour plots show that the LUMO is primarily
associated with a * antibonding orbital located on the aryl‐
linker with a smaller component lying on the NHC units. The
HOMO is primarily ligand centred (69%), with a smaller
contribution (31%) from the Au(I) 5d orbitals. TD‐DFT has been
employed to calculate the nature of the transitions involved in
the electronic absorption spectra (Table 2), which are, as
expected, best described as a combination of LC and ML‐LCT
processes.
LUMO
HOMO
Figure 10. CAM‐B3LYP/def2‐SVP molecular orbitals of the cationic part of complex 2b.
6 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 7 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
2.051(5), C1‐N2 1.353(7), C5‐N2 1.428(7), C5‐C10 1.396(7), C10‐N3 1.424(7), C14‐
N3 1.381(7), C14‐Ru1 2.035(5), Cl‐Ru1 2.4182(13), Ru1‐CT 1.734(5); CT‐Ru1‐Cl
View Article Online
126.7(2), CT‐Ru1‐C1 128.2(2), CT‐Ru1‐C14 128.9(2), C14‐Ru1‐C1 88.4(2), C14‐
DOI: 10.1039/C6DT01129B
Ru1‐Cl 84.4(2), C1‐Ru1‐Cl 85.4(2). CT is the centroid of the p‐cymene ligand.
The ruthenium center shows
a distorted tetrahedral
coordination environment considering the two carbene carbon
atoms of the chelating ligand, the chlorine atom and the
centroid of the p‐cymene molecule. The chelating ligand forms
a 7‐member coordination ring with a boat conformation. The
Ccarbene‐Ru‐Ccarbene bond angle is 88.4(2)°, and the Ccarbene‐Ru‐Cl
bond angles are 84.4(2) and 85.4(2)° while the bond angles at
the ruthenium atom involving the centroid of the p‐cymene
ligand are wider spanning from 126.7(2) to 128.9(2)° as usually
observed in other ruthenium (arene) NHC complexes in the
literature.49 The Ccarbene‐Ru, Ru‐Cl and Ru‐C bond distances for
the p‐cymene ligand lie in the usual range.
Scheme 5. Synthesis of the iridium(III) and ruthenium(II) di(N‐heterocyclic
carbene) complexes.
The iridium(III) complex tends to slowly (in ca. 10 days) react in
solution and, in the NMR spectra, appears a second set of
signal, related to the new species 4a’, formed by replacement
of the chloride ligand with a deuterated acetonitrile solvent
molecule. The formation of the dicationic complex
Unfortunately, reaction of the silver complexes 1b,c with
[RuCl2(p‐cymene)]2 or [IrCl2Cp*]2 in acetonitrile in different
reaction conditions (molar ratios of the reagents, temperature,
reaction time) does not allow the isolation of a pure product.
For example the 1H‐NMR spectra of the ruthenium(II) reaction
mixtures show the signals of free p‐cymene, probably due to
decomposition processes, whose presence is also apparent
from the dark‐green color of the reaction mixture. In the
literature22a,24a the coordination of meta‐phenylene based
dicarbene is often accompanied also by the metalation of the
C2 carbon atom of the aromatic bridge; however, it is
important to underline that generally the adopted synthetic
procedure is different from the one used in this work and
involves the deprotonation of the carbene proligand with a
strong base in the presence of the proper metal precursor.
[IrCp*L(CD3CN)]2+
(4a’) has been supported by a qualitative
test, that is by addition of AgPF6 to a freshly prepared solution
of complex 4a: a new set of NMR signal emerges and coincides
with that observed on 4a standing. The changes observed in
the 1H and 13C‐NMR spectra further point to the formation of a
dicationic complex: in particular, the signals of the dicarbene
ligand move downfiled, as a consequence of the increased
positive charge on the complex, with the exception of the
carbene carbon, which instead moves upfield (150.3 for 4a’
and 157.0 for 4a). This is a consequence of the higher Lewis
acidity of the metal center and a similar behavior has been
already reported for other iridium(III) or palladium(II)
complexes.47a,48
Conclusions
The crystal structure of complex 5a has been fully elucidated
by X‐ray diffraction analysis and in the crystals of 5a, cationic
In this work, we have synthesized three different dinuclear
silver(I) complexes of general formula [Ag2(diNHC)2](PF6)2
bearing bridging di(N‐heterocyclic carbene) ligands with
phenylene linkers between the carbene moieties. The
transmetalation of the diNHC ligand from silver(I) complexes
to gold(I) and copper(I) was successful, and the copper(I) and
gold(I) complexes displayed the same coordination geometries
as the precursor Ag(I) complexes. The same transmetallation
procedure furnished chelating complexes of ruthenium(II) and
iridium(III) with the ortho‐phenylene bridged dicarbene ligand.
We are currently exploring possible catalytic applications of
the resulting complexes, for example in transfer
hydrogenation.
‐
moieties, PF6 anions and acetonitrile solvent molecules are
present. The ORTEP view of the cationic complex in 5a is
reported in Figure 12 together with the atomic labelling
scheme; a list of the most important bond distances and
angles is collected in the caption.
Experimental
All manipulations of air and moisture sensitive compounds
were carried out using standard Schlenk techniques under an
atmosphere of argon or nitrogen or using a dry‐box. The
reagents were commercially available and generally used as
received. All solvents were purified and dried by standard
methods. The 1,1’‐(phenylene)bis(imidazole) precursors were
Figure 12. ORTEP view of the cationic complex in 5a. Ellipsoids are drawn at their
‐
30% probability. Hydrogen atoms, PF6 anions and acetonitrile molecules have
been omitted for clarity. Selected bond distances (Å) and angles (deg): C1‐Ru1
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 7
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 8 of 12
ARTICLE
Journal Name
prepared according to literature procedures.35 Generally NMR CH Ar), 7.91 (s, 2H, CH), 8.02 ‐ 8.04 (m, 1H, CH Ar), 9.25 (s, 2H,
View Article Online
DOI: 10.1039/C6DT01129B
1
spectra were recorded either on a Bruker Avance 300 (300.1 NCHN). 31P{ H} NMR (CD3CN, 121 MHz): δ ‐144.6 (heptet, PF6).
MHz for H, 75.5 MHz for 13C and 121.5 MHz for 31P) or on a [H2(Lpara)](PF6)2. White solid, yield 80%. H NMR (CD3CN, 300
1
1
Bruker Avance 400 (400 MHz for H and 100 MHz for 13C) at MHz): δ 3.96 (s, 6H, CH3), 7.58 (s, 2H, CH), 7.82 (s, 2H, CH), 7.85
1
298 K unless otherwise stated; chemical shifts (δ) are reported (s, 4H, CH Ar), 8.96 (s, 2H, NCHN). 31P{1H} NMR (CD3CN, 121
1
in units of ppm relative to the residual solvent signals (for H MHz): δ ‐144.6 (heptet, PF6).
and 13C) or to 85% H3PO4 (for 31P). ESI‐MS analyses were General procedure for the syntheses of the silver(I)
performed using a LCQ‐Duo (Thermo‐Finnigan) operating in complexes [Ag2L2](PF6)2, 1a‐1c.
positive ion mode. Instrumental parameters: capillary voltage
[H2L](PF6)2 (0.10 g, 0.19 mmol) and Ag2O (0.12 g, 0.52 mmol)
10 V, spray voltage 4.5 kV, capillary temperature 200 °C, mass
were placed in a two neck round bottom flask. Subsequently,
scan range from 150 to 2000 amu, N2 was used as sheath gas,
CH3CN (10 mL) was added and the reaction mixture was stirred
and the He pressure inside the trap was kept constant. The
for 24 hours at 65 °C. Afterwards, it was filtered through Celite
pressure directly read by an ion gauge (in the absence of the
and the filtrate was concentrated at low pressure. Addition of
N2 stream) was 1.33 × 10−5 Torr. Sample solutions were
diethyl ether (10 mL) afforded the product as a white solid,
prepared by dissolving the compounds in acetonitrile and were
that was filtered and dried under vacuum.
1a. Grey solid, yield 40%. 1H NMR (CD3CN, 300 MHz): δ 3.81 (s,
directly infused into the ESI source by a syringe pump at
8μL/min flow rate. Elemental analysis were carried out by the
microanalytical laboratory of Chemical Sciences Department
(University of Padova) with a Fisons EA 1108 CHNS‐O
apparatus.
General procedure for the synthesis of the 1,1’‐dimethyl‐3,3’‐
(phenylene)bis(imidazolium) diiodide salts [H2L]I2.
6H, CH3), 7.04 (s, 2H, CH), 7.20 (s, 2H, CH), 7.37 (m, 2H, CH Ar),
7.47 (m, 2H, CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 39.1
(CH3), 123.6 (CH), 124.2 (CH), 128.7 (CH Ar), 131.3 (CH Ar),
135.8 (C Ar), 186.7 (CAg). ESI‐MS+ (CH3CN): m/z 836.88
[Ag2L2PF6]+, 690.97 [Ag2L2]+, 346.09 [Ag2L2]2+. Crystals of
complex 1a were obtained by slow diffusion of diethyl ether
CH3I (120 μL, 1.9 mmol) was added to a solution of the into a solution of the complex.
appropriate 1,1’‐(phenylene)bis(imidazole) (0.55 g, 0.74 mmol) 1b. Grey solid, yield 32%. 1H NMR (CD3CN, 300 MHz): δ 3.97 (s,
3
in DMSO (1 mL). The reaction mixture was stirred for 24 hours 6H, CH3), 7.31 (m, 1H, CH Ar), 7.38 (d, JHH = 1.8 Hz, 2H, CH),
at room temperature and an orange solution was obtained. 7.48 (d, 3JHH = 1.8 Hz, 2H, CH), 7.56 (m, 3H, CH Ar). 13C{1H} NMR
Addition of CH2Cl2 (35 mL) affords the product as an off‐white (CD3CN, 75 MHz): δ 39.2 (CH3), 120.5 (CH Ar), 122.7 (CH), 124.5
solid, which was filtered and dried under vacuum. The NMR (CH), 124.9 (CH Ar), 131.0 (CH Ar), 141.5 (C Ar), 181.7 (CAg).
spectra of the diimidazolium salts compare well with those ESI‐MS+ (CH3CN): m/z 836.88 [Ag2L2PF6]+, 691.04 [Ag2L2]+,
reported in the literature.32b,33,35
346.19 [Ag2L2]2+. Crystals of complex 1b were obtained by
1
[H2(Lortho)]I2. White solid, yield 94%. H NMR (d6‐DMSO, 300 diffusion of vapours between diethyl ether and an acetonitrile
MHz): δ 3.92 (s, 6H, CH3), 7.74 (s, 2H, CH), 7.85 (s, 2H, CH), 7.93 solution of the complex.
(s, 4H, CH Ar), 9.45 (s, 2H, NCHN).
1c. Grey solid, yield 20%. 1H NMR (CD3CN, 300 MHz): δ 3.98 (s,
1
[H2(Lmeta)]I2. White solid, yield 95%. H NMR (d6‐DMSO, 300 6H, CH3), 7.39 (s, 2H, CH), 7.54 (s, 2H, CH), 7.65 (s, 4H, CH Ar).
MHz): δ 3.99 (s, 6H, CH3), 7.99 (s, 3H, CH Ar), 8.02 (s, 2H, CH), 13C{1H} NMR (CD3CN, 75 MHz): δ 39.7 (CH3), 122.3 (CH), 124.4
8.29 (s, 1H, CH Ar), 8.36 (s, 2H, CH), 9.86 (s, 2H, NCHN).
(CH), 125.4 (CH Ar), 141.0 (C Ar), 180.0 (CAg). ESI‐MS+ (CH3CN):
[H2(Lpara)]I2. White solid, yield 91%. H NMR (d6‐DMSO, 300 m/z 836.89 [Ag2L2PF6]+, 691.04 [Ag2L2]+, 346.22 [Ag2L2]2+.
1
MHz): δ 3.97 (s, 6H, CH3), 8.00 (s, 2H, CH), 8.09 (s, 4H, CH Ar) General procedure for the syntheses of gold(I) complexes
8.38 (s, 2H, CH), 9.87 (s, 2H, NCHN).
[Au2L2](PF6)2 2a‐2c.
General procedure for the synthesis of the 1,1’dimethyl‐3,3’‐
(phenylene)bis(imidazolium) bis(hexafluorophosphate) salts
[H2L](PF6)2.
A solution of AuCl(SMe2) (0.031 g, 0.105 mmol) in acetonitrile
(5 mL) was added to a solution of [Ag2L2](PF6)2 (0.051 g, 0.052
mmol) in the same solvent (5 mL). The reaction mixture was
A solution of NH4PF6 (0.28 g, 1.7 mmol) in MeOH (1 mL) was stirred for 2 hours at room temperature. Afterwards, it was
added to solution of 1,1’‐dimethyl‐3,3’‐ filtered on Celite and the filtrate was concentrated at low
a
(phenylene)bisimidazolium diiodide (0.30 g, 0.61 mmol) in pressure. Addition of diethyl ether (15 mL) afforded the
MeOH (4 mL). The mixture was stirred for two hours at room product as a white solid, which was filtered and dried under
temperature, giving a white solid that was filtered and dried vacuum.
under vacuum.
2a. White solid, yield 30%. Anal. Calcd for C28H28N8Au2F12P2: C,
1
[H2(Lortho)](PF6)2. White solid, yield 76%. H NMR (CD3CN, 300 28.98; H, 2.43; N, 9.66%. Found: C, 29.09; H, 2.40; N, 9.36%. 1H
MHz): δ 3.90 (s, 6H, CH3), 7.35 (d, JHH = 1.8 Hz, 2H, CH), 7.46 NMR (CD3CN, 300 MHz): δ 3.82 (s, 6H, CH3), 7.03 (d, 3JHH = 1.5
3
(d, 3JHH = 1.8 Hz, 2H, CH), 7.73 ‐ 7.76 (m, 2H, CH Ar), 7.88 ‐ 7.91 Hz, 2H, CH), 7.21 (d, 3JHH = 1.5 Hz, 2H, CH), 7.42 (m, 2H, CH Ar),
(m, 2H, CH Ar), 8.66 (s, 2H, NCHN). 31P{1H} NMR (CD3CN, 121 7.51 (m, 2H, CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 38.0
MHz): δ ‐144.6 (heptet, PF6).
(CH3), 123.9 (CH), 124.5 (CH), 129.1 (CH Ar), 131.9 (CH Ar),
1
[H2(Lmeta)](PF6)2. White solid, yield 76%. H NMR (CD3CN, 300 135.5 (C Ar), 185.3 (CAu). ESI‐MS+ (CH3CN): m/z 1015.08
MHz): δ 3.98 (s, 6H, CH3), 7.60 (s, 2H, CH), 7.81 ‐ 7.88 (m, 3H, [Au2L2PF6]+, 435.42 [Au2L2]2+. Crystals of complex 2a were
8 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 9 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
obtained by diffusion of vapours between diethyl ether and an CAr not detected. ESI‐MS+ (CH3CN): m/z 746.95 [Cu2L2PF6]+,
View Article Online
DOI: 10.1039/C6DT01129B
acetonitrile solution of the complex.
601.25 [Cu2L2]+, 301.33 [Cu2L2]2+.
1
2b. White solid, yield 38%. Anal. Calcd for C28H28N8Au2F12P2: C, 3c. Off‐white solid, yield 30%. H NMR (CD3CN, 300 MHz): δ
28.98; H, 2.43; N, 9.66%. Found: C, 28.75; H, 2.49; N, 10.06%. 3.99 (s, 6H, CH3), 7.34 (d, 3JHH = 1.8 Hz, 2H, CH), 7.47 (d, 3JHH
=
1H NMR (CD3CN, 300 MHz): δ 3.98 (s, 6H, CH3), 7.36 ‐ 7.44 (m, 1.8 Hz, 2H, CH) 7.61 (s, 4H, CH Ar). 13C{1H} NMR (CD3CN, 75
6H, CH + CH Ar), 7.64 (m, 2H, CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 39.1 (CH3), 122.2 (CH), 124.7 (CH), 125.9 (CH Ar), 137.2
MHz): δ 38.5 (CH3), 122.4 (CH Ar), 123.3 (CH), 124.5 (CH), 126.6 (C Ar), 177.2 (CCu). ESI‐MS+ (CH3CN): m/z 747.05 [Cu2L2PF6]+,
(CH Ar), 131.2 (CH Ar), 140.3 (C Ar), 183.2 (CAu). ESI‐MS+ 601.13 [Cu2L2]+, 301.22 [Cu2L2]2+.
(CH3CN): m/z 1015.09 [Au2L2PF6]+, 435.40 [Au2L2]2+. Crystals of In situ synthesis of the copper complex 3a.
complex 2b were obtained by diffusion of vapours between
diethyl ether and an acetonitrile solution of the complex.
2c. White solid, yield 46%. Anal. Calcd for C30H31Au2F12N9P2
This compound was prepared in situ using the same procedure
described in the previous section, however the reaction was
carried out in a dry box in deuterated acetonitrile and the
1
(
2c∙CH3CN) C, 29.99; H, 2.60; N, 10.49%. Found: C, 30.97; H,
colorless solution was analyzed. H NMR (CD3CN, 300 MHz): δ
1
3.75 (s, 6H, CH3), 7.01 (d, 3JHH = 1.8 Hz, 2H, CH), 7.05 (d, 3JHH
=
2.65; N, 10.19%. H NMR (CD3CN, 300 MHz): δ 4.00 (s, 6H,
CH3), 7.40 (s, 2H, CH), 7.52 (s, 2H, CH), 7.74 (s, 4H, CH Ar).
13C{1H} NMR (CD3CN, 75 MHz): δ 39.2 (CH3), 122.5 (CH), 124.6
(CH), 126.1 (CH Ar), 139.8 (C Ar), 183.8 (CAu). ESI‐MS+ (CH3CN):
m/z 1015.07 [Au2L2PF6]+, 435.33 [Au2L2]2+.
1.8 Hz, 2H, CH), 7.56 (m, 2H, CH Ar), 7.64 (m, 2H, CH Ar).
13C{1H} NMR (CD3CN, 75 MHz): δ = 38.8 (CH3), 123.2 (CH),
123.3 (CH), 129.3 (CH Ar), 131.0 (CH Ar), 137.4 (C Ar), 180.1
(CCu). Upon standing 12 hours in air, the color of the solution
turned yellow and a new spectrum was recorded. The main
Direct synthesis of gold(I) complex 2b.
To a stirred slurry of (THT)AuCl (0.09 g, 0.28 mmol) and the signals are assigned to species 3a*. 1H NMR (CD3CN, 300 MHz):
diimidazolium diiodide salt (0.15 g, 0.28 mmol) in DMF (10 mL) δ 4.51 (s, 6H, CH3), 8.08 (m, 2H, CH Ar), 8.19 (d, JHH = 2.1 Hz,
at 110 °C was added sodium acetate (0.09 g, 1.21 mmol). The 2H, CH), 8.49 (m, 2H, CH Ar), 8.65 (d, JHH = 2.1 Hz, 2H, CH).
3
3
reaction mixture was stirred at this temperature for 2 h and 13C{1H} NMR (CD3CN, 75 MHz): δ = 42.6 (CH3), 119.3 (CH),
filtered while hot. The filtrate was cooled to room 119.5 (CH Ar), 123.7 (C Ar), 127.4 (NCN), 131.7 (CH), 132.7 (C
temperature and diethyl ether (50 mL) was added to Ar). 1H NMR (d6‐DMSO, 400 MHz): δ 4.60 (s, 6H, CH3), 8.12 (m,
precipitate the complex as a white powder. The crude product 2H, CH Ar), 8.67 (bs, 2H, CH), 8.80 (m, 2H, CH Ar), 9.50 (bs, 2H,
was dissolved in water, filtered and a saturated solution of CH). 13C{1H} NMR (d6‐DMSO, 100 MHz): δ 41.7 (CH3), 118.3
KPF6 in water (2 mL) was added. The resultant precipitate was (CH), 118.9 (CH Ar), 123.2 (C Ar), 127.4 (NCN), 130.8 (CH),
recrystallized from a mixture of acetonitrile and diethyl ether. 131.7 (C Ar).
Yield: 0.06 g, 37%. H NMR (d6‐DMSO, 400 MHz): δ 4.01 (s, Synthesis of the iridium(III) complex [IrClCp*(Lortho)](PF6), 4a.
1
12H, CH3), 7.45 (t, 3JHH = 8.0 Hz, 2H, CH Ar), 7.63 (t, JHH = 2.0 Hz,
A solution of [IrCl2Cp*]2 (0.026 g, 0.033 mmol) in CH3CN (7 mL)
3
4
2H, CH Ar), 7.70 (dd, JHH = 8.0 Hz, JHH = 2.0 Hz, 4H, CH Ar),
was added to a solution of the silver complex 1a (0.031 g,
0.031 mmol) in the same solvent (7 mL). The reaction mixture
was stirred for 5 hours at room temperature. Afterwards, it
was filtered through Celite and the filtrate was concentrated at
low pressure. Addition of diethyl ether (15 mL) afforded the
product as a yellow solid, which was filtered and dried under
vacuum. Yield 20%. Anal. Calcd for C24H29N4ClF6IrP: C, 38.63; H,
3.92; N, 7.51%. Found: C, 36.34; H, 3.71; N, 6.61%. The
elemental analysis confirm the expected C/H/N ratio, however
3
3
7.75 (d, JHH = 1.7 Hz, 4H, CH), 7.81 (d, JHH = 1.7 Hz, 4H, CH).
13C NMR (d6‐DMSO, 100 MHz): δ 37.9 (NCH3), 121.3 (CH Ar),
123.0 (CH), 124.2 (CH), 125.5 (CH Ar), 130.3 (CH Ar), 139.0 (CH
Ar), 181.8 (CAu). ESI‐MS+ (CH3OH): m/z 1015.2
+
[C28H28N8Au2]PF6 , calcd 1015.14. m/z 435.3 [C28H28N8Au2]2+,
calcd 435.26.
General procedure for the syntheses of the copper(I)
complexes [Cu2L2](PF6)2, 3b and 3c.
the values are lower than the estimated ones probably
1
CuI (0.032 g, 0.017 mmol) was added to a solution of the because of a small amount of silver salt. H NMR (CD3CN, 300
appropriate complex [Ag2L2](PF6)2 (0.041 g, 0.042 mmol) in MHz): δ 1.42 (s, 15H, CH3), 3.92 (s, 6H, CH3), 7.38 (d, 3JHH = 2.1
acetonitrile (5 mL). The reaction mixture was stirred for one Hz, 2H, CH), 7.49 (d, 3JHH = 2.1 Hz, 2H, CH), 7.52 (m, 2H, CH Ar),
hour. Afterwards, it was filtered through Celite and the filtrate 7.62 (m, 2H, CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 9.1 (CH3),
was concentrated at low pressure. Addition of diethyl ether 40.1 (NCH3), 94.0 (CCp*), 124.7 (CH), 127.3 (CH), 129.6 (CH Ar),
(10 mL) affords the product as a white/grey solid, which was 130.7 (CH Ar), 134.2 (C Ar), 157.0 (CIr). ESI‐MS+ (CH3CN): m/z
filtered and dried under vacuum. Unfortunately, the instability 601.26 [IrClCp*L]+, 363.19 [IrClCp*]+. The NMR solution of
of the products does not allow to obtain good elemental complex 4a slowly evolves and in ca. 10 days a second similar
analyses. For this reason, the products were characterised only set of signals emerges. The new signals can be attributed to
by means of spectroscopic techniques.
the dicationic species [IrCp*L(CD3CN)](PF6)2 (4a’), in which the
1
3b. Off‐white solid, yield 29%. H NMR (CD3CN, 300 MHz): δ = chloride ligand has been substituted by an deuterated
4.00 (s, 6H, CH3), 7.09 (m, 1H, CH Ar), 7.35 (d, 3JHH = 1.8 Hz, 2H, acetonitrile solvent molecule. To confirm this, [IrClCp*L](PF6)
CH), 7.49, (s, 1H, CH Ar), 7.52 (d, 3JHH = 1.8 Hz, 2H, CH), 7.58 (m, 4a (5.5 mg, 0.0074 mmol) and AgPF6 (7.5 mg, 0.0134 mmol, 3.5
2H, CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 39.2 (CH3), 122.2 eq.) were placed in a vial. Afterwards CD3CN (1.0 ml) was
(CH Ar), 124.1 (CH Ar), 124.7 (CH), 130.5 (CH Ar), 177.7 (CCu), added and the solution was heated at 50 °C for two hours,
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 9
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 10 of 12
ARTICLE
Journal Name
1
giving complete conversion of complex 4a in 4a’. H NMR lifetimes in the ns‐

s range were determined with the single
View Article Online
DOI: 10.1039/C6DT01129B
(CD3CN, 300 MHz): δ 1.50 (s, 15H, CH3), 3.77 (s, 6H, CH3), 7.50 photon counting technique by means of the same Edinburgh
(d, 3JHH = 2.1 Hz, 2H, CH), 7.58 (m, 4H, CH + CH Ar), 7.68 (m, 2H, FLS980 spectrometer using pulsed NanoLED excitation sources
CH Ar). 13C{1H} NMR (CD3CN, 75 MHz): δ 9.3 (CH3), 39.8 (NCH3), at 330 nm, (pulse width
 0.3 ns, after deconvolution). Solid
96.4 (CCp*), 125.8 (CH), 127.3 (CH), 129.8 (CH Ar), 131.3 (CH samples, em have been calculated by corrected emission
Ar), 133.2 (C Ar), 150.3 (CIr). ESI‐MS+ (CH3CN): m/z 585.17 spectra obtained from an apparatus consisting of a barium
[IrCp*L(HDO)]+, 565.34 [IrCp*L]+, 303.38 [IrCp*L(CH3CN)]2+, sulphate coated integrating sphere (4 or 6 inches), a 450W Xe
283.32 [IrCp*L]2+.
lamp and a R928 photomultiplier tube signal detectors,
following the procedure described by De Mello et al.52
Experimental uncertainties are estimated to be ± 8% for
lifetime determinations, ± 20% for emission quantum yields.
Theoretical Methods
Synthesis of the ruthenium(II) complex [RuCl(Lortho)(
cymene)](PF6), 5a.
p‐
Complex 1a (0.042 g, 0.043 mmol) and [RuCl2(p‐cymene)]2
(0.053 g, 0.086 mmol) were placed in a two neck round
bottom flask. Subsequently, CH3CN (5 mL) was added and the Density functional theory (DFT) calculations were carried out
reaction mixture was stirred for one hour at room within the Gaussian 09 suite of programs.53 Ground state
temperature. Afterwards, it was filtered through Celite and the geometries were optimised in the absence of solvent with the
filtrate was concentrated at low pressure. Addition of diethyl M06‐L functional54 in conjunction with the def2‐SVP basis set
ether (10 mL) afforded the product as an orange solid, which and associated core potential.55 Single‐point energy
was filtered and dried under vacuum. Yield 23%. Anal. Calcd calculations were carried out with the def2‐TZVP basis set and
for C24H28N4ClF6PRu∙CH3CN: C, 44.93; H, 4.50; N, 10.08. Found: core potential. The polarisable continuum model (PCM)56 self‐
C, 44.98; H, 4.25; N, 10.30%. 1H NMR (CD3CN, 300 MHz): δ 0.85 consistent reaction field (SCRF) was used to model solvent
(d, 3JHH = 6.9 Hz, 6H, CH(CH3)2), 1.65 (hept, 1H, CH(CH3)2), 1.94 effects at the gas‐phase optimised geometries with a solvent
(s superimposed to the deuterated solvent signal, 3H, CH3), of acetonitrile, consistent with the experimental system.
4.04 (s, 6H, NCH3), 5.20 (d, 3JHH = 6.3 Hz, 2H, CH Ar p‐cymene), Frontier MO energies were calculated using DFT MOs
3
5.32 (d, JHH = 6.3 Hz, 2H, CH Ar p‐cymene), 7.39 (s, 2H, CH), (including solvent effects) with M06‐L and CAM‐B3LYP57 An
7.48 (m, 4H, CH Ar + CH), 7.62 (m, 2H, CH Ar). 13C{1H} NMR SCF convergence criteria of 10‐8 a.u. was employed
(CD3CN, 75 MHz): δ 18.7 (CH3 p‐cymene), 22.7 (CH(CH3)2), 31.8 throughout.
(CH(CH3)2), 40.8 (NCH3), 86.1 (CH Ar p‐cymene), 91.6 (CH Ar p‐
cymene), 124.5 (CH), 127.2 (CH), 128.9 (CH Ar), 130.2 (CH Ar),
134.4 (C Ar), 179.5 (CRu). ESI‐MS+ (CH3CN): m/z 509.05
[RuClL(p‐cymene)]+, 415.82 [RuCl(p‐cymene)PF6]+, 375.01
[RuClL]+, 311.86 [RuCl(CH3CN)(p‐cymene)]+. Crystals of
complex 5a were obtained by diffusion of vapours between
diethyl ether and an acetonitrile solution of the complex.
X‐ray crystal structure determination of compounds 1a, 1a*,
1b, 2a, 2b and 5a.
Acknowledgements
C.T. thanks the University of Padova for financial support
(CPDA140431). M.M. thanks Fondazione Cassa di Risparmio di
Padova e Rovigo (www.fondazionecariparo.it) for a PhD grant.
G.A. thanks thanks Italian projects PON R&C 2007‐2013
“MAAT” Molecular NAnotechnology for HeAlth and
EnvironmenT (PON02 00563 3316357) and EFOR‐Energia da
FOnti Rinnovabili (Iniziativa CNR per il Mezzogiorno L.
191/2009 art. 2 comma 44).
The crystallographic data for all complexes were collected on a
Bruker Smart Apex II single‐crystal diffractometer working with
monochromatic Mo‐Kα radiation and equipped with an area
detector.50 The structures were solved by direct methods and
refined against F2 with SHELXL‐2014/751 with anisotropic
thermal parameters for all non‐hydrogen atoms. Idealized
geometries were assigned to the hydrogen atoms. Details for
the X‐ray data collection are reported in the supporting
information. Crystallographic data have been deposited with
the Cambridge Crystallographic Data Centre as supplementary
publication. Copies of the data can be obtained free of charge
on application to the CCDC, 12 Union Road, Cambridge CB2
Notes and references
1
(a) S. P. Nolan, N‐Heterocyclic Carbenes, Effective Tools for
Organometallic Synthesis. Weinheim: Wiley‐VCH; 2014. (b) S.
Diez‐Gonzalez, N‐Heterocyclic Carbenes: From Laboratory
Curiosities to Efficient Synthetic Tools. Cambridge: RSC
Catalysis Series, RSC; 2010. (c) C. S. J. Cazin, N‐Heterocyclic
Carbenes in Transition Metal Catalysis and Organocatalysis,
in Catalysis by Metal Complexes. vol. 32. Heidelberg:
Springer; 2010. (d) O. Kühl, Functionalised N‐heterocyclic
carbene complexes. John Wiley and Sons; 2010. (e) F.
Glorius, N‐Heterocyclic Carbenes in Transition Metal
Catalysis, in Topics in Organometallic Chemistry, vol. 21,
Heidelberg: Springer; 2007.
(a) F. E. Hahn and M. C. Jahnke, Angew. Chem. Int. Ed., 2008,
47, 3122. (b) W. A. Herrmann, Angew. Chem. Int. Ed., 2002,
41, 1290. (c) D. Bourissou, O. F. Guerret, P. Gabbaï and G.
Bertrand, Chem. Rev., 2000, 100, 39. (d) A. J. Arduengo, R. L.
Harlow and M. J. Kline, J. Am. Chem. Soc., 1991, 113, 361. (e)
W. A. Herrmann, T. Weskamp and V. P. W. Böhm, Adv.
Organomet. Chem., 2001, 48, 1.
1EZ,
U.K.
(fax,
(+44)
1223
336033;
e‐mail,
deposit@ccdc.cam.ac.uk).
Photophysical measurements
2
Uncorrected emission spectra were obtained with an
Edinburgh FLS980 spectrometer equipped with a peltier‐
cooled Hamamatsu R928 photomultiplier tube (185‐850 nm).
An Edinburgh Xe900 450 W Xenon arc lamp was used as
exciting light source. Corrected spectra were obtained via a
calibration curve supplied with the instrument. Emission
10 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins

Page 11 of 12
Dalton Transactions
Please do not adjust margins
Journal Name
ARTICLE
3
4
(a) M. Scholl, T. M. Trnka, J. P. Morgan and R. H. Grubbs, 14 (a) U. Son, K. H. Park, Y.‐S. Lee, B. Y. Kim, C. H. Choi, M. S.
View Article Online
Tetrahedron Lett., 1999, 40, 2247. (b) J. Huang, H. Z. Schanz,
E. D. Stevensenand S. P. Nolan, Organometallics, 1999, 18
Lah, Y. H. Jang, D.‐J. Jang and Y. K. DCOhIu: 1n0g.1,0I3n9o/Crg6D. TC0h1e12m9B.,
2004, 43, 6896. (b) G. Duan and V. W.‐W. Yam, Chem. ‐ Eur.
J., 2010, 16, 12642. (c) J. Dinda, S. Liatard, J. Chauvin, D.
Jouvenot and F. Loiseau, Dalton Trans., 2011, 40, 3683. (d) D.
G. Brown, N. Sanguantrakun, B. Schulze, U. S. Schubert and
C. P. Berlinguette, J. Am. Chem. Soc., 2012, 134, 12354. (e) G.
J. Barbante, P. S. Francis, C. F. Hogan, P. R. Kheradmand, D. J.
D. Wilson and P. J. Barnard, Inorg. Chem., 2013, 52, 7448. (f)
V. Leigh, W. Ghattas, R. Lalrempuia, H. Müller‐Bunz, M. T.
Pryce and M. Albrecht, Inorg. Chem., 2013, 52, 5395.
,
5375. (c) W. A. Herrmann, M. Elison, J. Fischer, C. Köcher and
G. R. J. Artus, Angew Chem. Int. Ed., 1995, 34, 2371. (d) L.
Mercs and M. Albrecht, Chem. Soc. Rev., 2010, 39, 1903.
(a) M. C. Gather, A. Köhnen and K. Meerholz, Adv. Mater.,
2011, 23, 233. (b) R. D. Costa, E. Ortí, H. J. Bolink, S. Graber,
C. E. Housecroft and E. C. Constable, Adv. Funct. Mater.,
2010, 20, 1511. (c) T. Sajoto, P. I. Djurovich, A. Tamayo, M.
Yousufuddin, R. Bau, M. E. Thompson, R. J. Holmes and S. R.
Forrest, Inorg. Chem., 2005, 44, 7992. (d) Y. Unger, A. Zeller, 15 (a) M. Poyatos, J. A. Mata and E. Peris, Chem. Rev., 2009,
S. Ahrens and T. Strassner, Chem. Commun., 2008, 3263.
(a) K. M. Hindi, M. J. Panzner, C. A. Tessier, C. L. Cannon and
W. J. Youngs, Chem. Rev., 2009, 109, 3859. (b) A. Melaiye, R.
109, 3677. (b) J. A. Mata, M. Poyatos and E. Peris, Coord.
Chem. Rev., 2007, 251, 841. (c) A. Biffis, C. Tubaro and M.
Baron, Adv. Organomet. Chem., 2015, 63, 203.
5
S. Simons, A. Milsted, F. Pingitore, C. Wesdemiotis, C. A. 16 P. J. Barnard, M. V. Baker, S. J. Berners‐Price, B. W. Skelton
Tessier and W. J. Youngs, J. Med. Chem., 2004, 47, 973. (c) and A. H. White, Dalton Trans., 2004, 1038.
M. L. Teyssot, A. S. Jarrousse, M. Manin, A. Chevry, S. Roche, 17 V. J. Catalano and A. O. Etogo, J. Organomet. Chem., 2005,
F. Norre, C. Beaudoin, L. Morel, D. Boyer, R. Mahiou and A. 690, 6041.
Gautier, Dalton Trans., 2009, 34, 6894. (d) D. Brackemeyer, 18 P. J. Barnard, L. E. Wedlock, M. V. Baker, S. J. Berners‐Price,
A. Hervé, C. Schulte to Brinke, M. C. Jahnke and F. E. Hahn, J.
Am. Chem. Soc., 2014, 136, 7841. (e) C. Bazzicalupi, M.
D. A. Joyce, B. W. Skelton and J. H. Steer, Angew. Chem., Int.
Ed., 2006, 45, 5966.
Ferraroni, F. Papi, L. Massai, B. Bertrand, L. Messori, P. 19 (a) C. Tubaro, M. Baron, M. Costante, M. Basato, A. Biffis, A.
Gratteri, A. Casini, Angew. Chem. Int. Ed., 2016, 55, 4256. (f)
J.‐J. Zhang, C.‐M. Che and I. Ott, J. Organomet. Chem., 2015,
782, 37. (g) J. F. Arambula, R. McCall, K. J. Sidoran, D. Magda,
N. A. Mitchell, C. W. Bielawski, V. M. Lynch, J. L. Sesslerg and
Gennaro, A. A. Isse, C. Graiff and G. Accorsi, Dalton Trans.,
2013, 10952. (b) M. Baron, C. Tubaro, A. Biffis, M. Basato, C.
Graiff, A. Poater, L. Cavallo, N. Armaroli and G. Accorsi, Inorg.
Chem., 2012, 51, 1778.
K. Arumugam, Chem. Sci., 2016,
7
, 1245.
20 A. Biffis, M. Cipani, C. Tubaro, M. Basato, M. Costante, E.
6
7
R. Visbal and M. C. Gimeno, Chem. Soc. Rev., 2014, 43, 3551.
(a) K. Matsumoto, N. Matsumoto, A. Ishii, T. Tsukuda, M.
Hasegawa and T. Tsubomura, Dalton Trans., 2009, 6795. (b) 21 T. P. Pell, D. J. D. Wilson, B. W. Skelton, J. L. Dutton and P. J.
V. J. Catalano, L. B. Munro, C. E. Strasser and A. F. Samin,
Inorg. Chem., 2011, 50, 8465.
(a) X. Zhang, S. Gu, Q. Xia and W. Chen, J. Organomet. Chem., 22 (a) R. J. Rubio, G. T. S. Andavan, E. B. Bauer, T. K. Hollis, J.
Bressan, A. Venzo and C. Graiff, New J. Chem., 2013, 37,
4176.
Barnard,
Inorg.
Chem.,
2016,
http://dx.doi.org/10.1021/acs.inorgchem.6b00222.
8
9
2009, 694, 2359. (b) A.
Poethig
and
T.
Strassner,
Cho, F. S. Tham and B. Donnadieu, J. Organomet. Chem.,
2005, 690, 5353. (b) G. T. S. Andavan, E. B. Bauer, C. S. Letko,
Organometallics, 2011, 30, 6674.
(a) R. Visbal, I. Ospino, J. M. López‐de‐Luzuriaga, A. Laguna
and M. C. Gimeno, J. Am. Chem. Soc., 2013, 135, 4712. (b) S.
T. K. Hollis and F. S. Tham, J. Organomet. Chem., 2005, 690,
5938. (c) J. Cho, T. K. Hollis, T. R. Helgerta and E. J. Valente,
Gonell, M. Poyatos and E. Peris, Dalton Trans., 2016, 45
,
Chem. Commun., 2008, 5001. (d) J. Cho, T. K. Hollis, E. J.
5549. (c) F.‐F. Hung, W.‐P. To, J.‐J. Zhang, C. Ma, W.‐Y. Wong
and C.‐M. Che, Chem.‐Eur. J., 2014, 20, 8604.
Valente and J. M. Trate, J. Organomet. Chem., 2011, 696,
373. (e) X. Zhang, A. M. Wright, N. J. DeYonker, T. K. Hollis, N.
I. Hammer, C. E. Webster and E. J. Valente, Organometallics,
2012, 31, 1664. (f) T. R. Helgert, T. K. Hollis and E. J. Valente,
Organometallics, 2012, 31, 3002. (g) A. J. Huckaba, T. K.
Hollis, T. O. Howell, H. U. Valle and Y. Wu, Organometallics,
2013, 32, 69. (h) X. Zhang, B. Cao, E. J. Valente and T. K.
Hollis, Organometallics, 2013, 32, 752. (i) S. W. Reilly, G.
Akurathi, H. K. Box, H. U. Valle, T. K. Hollis and C. E. Webster,
J. Organomet. Chem.. 2016, 802, 32. (j) S. W. Reilly, C. E.
10 E.Q.‐X. Liu, F.‐B. Xu, Q.‐S. Li, H.‐B. Song and Z.‐Z. Zhang,
Organometallics, 2004, 23, 610.
11 Q.‐X. Liu, H.‐B. Song, F.‐B. Xu, Q.‐S. Li, X.‐S. Zeng, X.‐B. Leng
and Z.‐Z. Zhang, Polyhedron, 2003, 22, 1515.
12 (a) Y. Unger, D. Meyer and T. Strassner, Dalton Trans., 2010,
39, 4295. (b) Y. Unger, D. Meyer, O. Molt, C. Schildknecht, I.
Münster, G. Wagenblast and T. Strassner, Angew. Chem., Int.
Ed., 2010, 49, 10214. (c) R. Wai‐Yin Sun, A. Lok‐Fung Chow,
X.‐H. Li, J. J. Yan, S. Sin‐Yin Chui and C.‐M. Che, Chem. Sci.,
Webster, T. K. Hollis and H. U. Valle, Dalton Trans., 2016, 45
2823.
,
2011,
2, 728‐736. (d) P. Pinter, H. Mangold, I. Stengel, I.
Münster and T. Strassner, Organometallics, 2016, 35, 273. 23 M. Albrecht, R. H. Crabtree, J. Mata and E. Peris, Chem.
(e) M. Tenne, S. Metz, G. Wagenblast, I. Münster and T.
Commun., 2002, 32.
Strassner, Organometallics, 2015, 34, 4433. (f) H. Leopold, A. 24 Y. Canac, C. Lepetit, M. Abdalilah, C. Duhayon and R.
Tronnier, G. Wagenblast, I. Münster and T. Strassner,
Organometallics, 2016, 35, 959.
Chauvin, J. Am. Chem. Soc., 2008, 130, 8406.
25 (a) M. Raynal, R. Pattacini, C. S. J. Cazin, C. Vallée, H. Olivier‐
13 (a) F. Kessler, R. D. Costa, D. Di Censo, R. Scopelliti, E. Orti, H.
J. Bolink, S. Meier, W. Sarfert, M. Grätzel, M. K. Nazeeruddin
and E. Baranoff, Dalton Trans., 2012, 41, 180. (b) F. Monti, F.
Kessler, M. Delgado, J. Frey, F. Bazzanini, G. Accorsi, N.
Armaroli, H. J. Bolink, E. Ortí, R. Scopelliti, M. K. Nazeeruddin
and E. Baranoff, Inorg. Chem., 2013, 52, 10292. (c) Y. Zhou, J.
Bourbigou and P. Braunstein, Organometallics, 2009, 28,
4028. (b) W. Zuo and P. Braunstein, Organometallics, 2010,
29, 5535. (c) W. Zuo and P. Braunstein, Dalton Trans., 2012,
41, 636. (d) N. Darmawan, C.‐H. Yang, M. Mauro, M. Raynal,
S. Heun, J. Pan, H. Buchholz, P. Braunstein and L. De Cola,
Inorg. Chem., 2013, 52, 10756. (e) M. Jagenbrein, A. A.
Danopoulos and P. Braunstein, J. Organomet. Chem., 2015,
775, 169.
Jia, W. Li, H. Fei and M. Zhou, Chem. Commun., 2013, 49
,
3230. (d) G. J. Barbante, E. H. Doeven, P. S. Francis, B. D.
Stringer, C. F. Hogan, P. R. Kheradmand, D. J. D. Wilson and 26 L. Mercs, A. Neels, H. Stoeckli‐Evans and M. Albrecht, Inorg.
P. J. Barnard, Dalton Trans., 2015, 44, 8564. (e) B. D. Stringer, Chem., 2011, 50, 8188.
L. M. Quan, P. J. Barnard, D. J. D. Wilson and C. F. Hogan, 27 (a) A. R. Chianese, A. Mo, N. L. Lampland, R. L. Swartz and P.
Organometallics, 2014, 33, 4860.
T. Bremer, Organometallics, 2010, 29, 3019. (b) A. R.
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1‐3 | 11
Please do not adjust margins

Please do not adjust margins
Dalton Transactions
Page 12 of 12
ARTICLE
Journal Name
Chianese, S. E. Shaner, J. A. Tendler, D. M. Pudalov, D. Y. 49 (a) J. DePasquale, M. Kumar, M. Zeller and E. T. Papish,
View Article Online
Shopov, D. Kim, S. L. Rogers and A. Mo, Organometallics,
2012, 31, 7359. (c) A. R. Chianese, M. J. Drance, K. H. Jensen,
Organometallics, 2013, 32, 966. (b) DMO.I: 1P0o.1y0a3t9o/Cs,6DET.01M12a9sB‐
Marzá, M. Sanaú and E. Peris, Inorg. Chem., 2004, 43, 1793.
S. P. McCollom, N. Yusufova, S. E. Shaner, D. Y. Shopov and J. 50 APEX II v2012.2‐0 Software User Guide, SAINT, version 7.06a,
A. Tendler, Organometallics, 2014, 33, 457.
28 (a) A. Rit, T. Pape and F. E. Hahn, Organometallics, 2011, 30
SADABS, version 2.01, Bruker AXS Inc., Madison, WI, 2008.
51 G. M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr.,
2008, 64, 112‐122.
,
6393. (b) R. Maity, A. Rit, C. Schulte to Brinke, J. Kösters and
F. E. Hahn, Organometallics, 2013, 32, 6174.
29 Y.‐M. Zhang, J.‐Y. Shao, C.‐J. Yao and Y.‐W. Zhong, Dalton
Trans., 2012, 41, 9280.
30 B. K. Rana, V. Bertolasi, S. Pal, P. Mitra and J. Dinda, J. Mol.
Struct., 2013, 1049, 458.
31 S. Zlatogorsky, C. A. Muryn, F. Tuna, D. J. Evans and M. J.
Ingleson, Organometallics, 2011, 30, 4974.
32 (a) D. Munz, A. Poethig, A. Tronnier and T. Strassner, Dalton
Trans., 2013, 42, 7297. (b) A. Tronnier and T. Strassner,
Dalton Trans., 2013, 42, 9847.
33 A. R. Naziruddin, Z.‐J. Huang, W.‐C. Lai, W.‐J. Lin and W.‐S.
Hwang, Dalton Trans., 2013, 42, 13161.
52 J. C. De Mello, H. F. Wittmann and R. H. Friend, Adv. Mat.,
1997, 9, 230.
53 M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci,
G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P.
Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L.
Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J.
Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, T. Vreven, J. A. Montgomery, J. E. Peralta, F. Ogliaro,
M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N.
Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A.
Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N.
Rega, J. M. Millam, M. Klene, J. E. Knox, J. B. Cross, V.
Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann,
O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski,
R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P.
Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, Ö.
Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski and D. J. Fox,
Gaussian 09, Revision A.1, Gaussian 09, Revision A.1,
Gaussian, Inc.: Wallingford CT, 2009.
34 (a) W. D. Clark, G. E. Tyson, T. K. Hollis, H. U. Valle, E. J.
Valente, A. G. Oliver and M. P. Dukes, Dalton Trans., 2013,
42, 7338. (b) V. Charra, P. de Frémont, P.‐A. R. Breuil, H.
Olivier‐Bourbigou and P. Braunstein, J. Organomet. Chem.,
2015, 795, 25.
35 (a) V. C. Vargas, R. J. Rubio, T. K. Hollis and M. E. Salcido,
Org. Lett., 2003, 5, 4847. (b) C. Tubaro, A. Biffis, C. Gonzato,
M. Zecca and M. Basato, J. Mol. Catal. A: Chem., 2006, 248
,
93. (c) J. Z. Vlahakis, S. Mitu, G. Roman, E. P. Rodriguez, I. E. 54 Y. Zhao and D. G. Truhlar, J. Chem. Phys., 2006, 125, 194101.
Crandall and W. A. Szarek, Biorg. Med. Chem., 2011, 19
,
55 F. Weigend and R. Ahlrichs, Phys. Chem. Chem. Phys., 2005,
6525.
7, 3297.
36 (a) H. M. J. Wang and I. J. B. Lin, Organometallics, 1998, 17
,
56 J. Tomasi, B. Mennucci and R. Cammi, Chem. Rev., 2005, 105,
972. (b) J. C. Garrison and W. J. Youngs, Chem. Rev., 2005,
105, 3978.
37 Y.‐F. Han, G.‐X. Jin and F. E. Hahn, J. Am. Chem. Soc., 2013,
135, 9263.
2999.
57 T. Yanai, D. P. Tew and N. C. Handy, Chem. Phys. Lett., 2004,
393, 51.
38 R. Zhong, A. Pöthig, D. C. Mayer, C. Jandl, P. J. Altmann, W. A.
Herrmann and F. E. Kühn, Organometallics, 2015, 34, 2573
39 P. J. Barnard, M. V. Baker, S. J. Berners‐Price, B. W. Skelton
and A. H. White, Dalton Trans., 2004, 1038.
40 (a) A. Herbst, C. Bronner, P. Dechambenoit and O. S. Wenger,
Organometallics, 2013, 32, 1807. (b) J. Vaughan, D. J. Carter,
A. L. Rohl, M. I. Ogden, B. W. Skelton, P. V. Simpson and D. H.
Brown, Dalton Trans., 2016, 45, 1484. (c) T. P. Pell, B. D.
Stringer, C. F. Hogan, D. J. D. Wilson and P. J. Barnard,
unpublished results.
41 (a) D. H. Brown, G. L. Nealon, P. V. Simpson, B. W. Skelton,
and Z. Wang, Organometallics, 2009, 28, 1965. (b) J. C. C.
Chen and I. J. B. Lin, J. Chem. Soc., Dalton Trans., 2000, 839.
(c) A. Caballero, E. Díez‐Barra, F. A. Jalón, S. Merino, A. M.
Rodríguez and J. Tejeda, J. Organomet. Chem., 2001, 627
263.
,
42 F. Jean‐Baptiste dit Dominique, H. Gornitzka, A. Sournia‐
Saquet and C. Hemmert, Dalton Trans., 2009, 340.
43 (a) J. R. Ames, M. A. Houghtaling, D. L. Tellian and T. P.
Mitchell, Can. J. Chem., 1997, 75, 28. (b) Z. Shi and R. P.
Thummel, J. Org. Chem., 1995, 60, 5935.
44 P. Pyykkö, Angew. Chem. Int. Ed., 2004, 43, 4412.
45 J. Muñiz, E. Sansores, J. A. Reyes‐nava, V. H. Ramos‐sanchez
and A. Olea, Int. J. Quant. Chem., 2011, 111, 4378.
46 L. Magnko, M. Schweizer, G. Rauhut, M. Schütz, H. Stoll and
H.‐J. Werner, Phys. Chem. Chem. Phys., 2002, 4, 1006.
47 (a) A. Volpe, A. Sartorel, C. Tubaro, L. Meneghini, M. Di
Valentin, C. Graiff and M. Bonchio, Eur. J. Inorg. Chem., 2014,
665. (b) C. Tubaro, D. Bertinazzo, M. Monticelli, O. Saoncella,
A. Volpe, M. Basato, D. Badocco, P. Pastore, C. Graiff and A.
Venzo, Eur. J. Inorg. Chem., 2014, 1524.
48 G. Buscemi, M. Basato, A. Biffis, A. Gennaro, A. A. Isse, M. M.
Natile and C. Tubaro, J. Organomet. Chem., 2010, 695, 2359.
12 | J. Name., 2012, 00, 1‐3
This journal is © The Royal Society of Chemistry 20xx
Please do not adjust margins