Straightforward access to chalcogenoureas derived from N-heterocyclic carbenes and their coordination chemistry

Article abstract of DOI:10.1039/d0dt02558e

Chalcogen-based urea compounds supported by a wide range of N-heterocyclic carbenes are synthesised and fully characterised. Coordination of selenoureas is further explored with Group 11 transition metals to form new copper, gold and silver complexes. Sin

Full text of DOI:10.1039/d0dt02558e

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D. J. Nelson, N. V. Tzouras, T. A. C. A. Bayrakdar, S. P. Nolan and K. Van Hecke, Dalton Trans., 2020, DOI:
10.1039/D0DT02558E.
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Pages 3073-3412
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DOI: 10.1039/D0DT02558E
ARTICLE
Straightforward access to chalcogenoureas derived from N-
heterocyclic carbenes and their coordination chemistry
Marina Saab,a David Nelson,*b Nikolaos V. Tzouras,a Tahani A. C. A. Bayrakdar,a Steven P. Nolan,*a
Received 00th January 20xx,
Accepted 00th January 20xx
Fady Nahra*a,c and Kristof Van Hecke*a
DOI: 10.1039/x0xx00000x
Chalcogen-based urea compounds supported by a wide range of N-heterocyclic carbenes are synthesised and fully
characterised. Coordination of selenoureas is further explored with Group 11 transition metals to form new copper, gold
and silver complexes. Single crystal X-ray analyses unambiguously establish the solid-state coordination of these complexes
and show that the geometry of a complex is highly influenced by a combination of electronic properties -mainly -accepting
ability- and steric hindrance of the ligands, as well as the nature of the metal, affording a variety of coordination behaviours.
In this report, we investigate these phenomena using several experimental methods.
be noted that in all approaches, a significant excess of elemental
chalcogen is needed. NHC-derived telluroureas, on the other
hand, are more scarcely reported, owing to the lower reactivity
of elemental tellurium and its more metallic character when
compared to selenium and sulfur.14-16
Introduction
Due to their unique structural properties, reactivity and
coordination characteristics, N-heterocyclic carbenes (NHCs)
have attracted significant attention in the scientific community
over the last decades. Their unique properties have made them
highly useful in several application.1 The quest to better
understand these species, more specifically their electronic and
steric properties, in order to achieve better ligand designs and
ultimately more efficient catalysts, have been a major driving
force for the current research in this field.2-4
Our interest lies in better understanding the π-accepting
ability of commonly used NHCs and its influence on their
coordination behaviour with transition metals as well as the
reactivity of NHC-based complexes in catalysis. To this end, our
approach has been based on synthesising NHC-derived
selenoureas, analysing these by 77Se NMR spectroscopy,5,6 and
investigating trends in their coordination chemistry to transition
metals such as copper, silver and gold.7,8 In addition to revealing
the π-accepting ability of the parent NHC,9-12 selenoureas have
themselves found applications in coordination chemistry with
several transition metals.13-15 Other chalcogen-based
derivatives, such as thio- and telluroureas, have also made an
impact in this field,13-17 although the tellurium analogues are far
less common.14 NHC-based seleno- and thioureas can typically
be synthesised either by deprotonating the corresponding
imidazolium salts using a strong base (e.g. KOtBu, NaH), or by
adding elemental selenium or sulfur to a free NHC species.14,15
Some reports have used K2CO3 in methanol yielding lower
yields, as it generates the strong base KOMe in situ.18 It should
We have recently developed a systematic approach to the
synthesis of NHC-based compounds by means of weak bases
such as K2CO3 and NEt3. In a recent report, we accessed [S(IPr)]
and [Se(IPr)] compounds (IPr = N,N’-bis[2,6-(di-isopropyl)-
phenyl]imidazol-2-ylidene) using NEt3 as the base.19 In this
report, the synthesis of various NHC-based seleno-, thio- and
telluroureas is investigated, using two different weak bases
(K2CO3 and NEt3) (Scheme 1). We have also built on our previous
work concerning the coordination of transition metals to
selenoureas.7,8 The coordination library of the latter to copper,
gold and silver is investigated and compared in more details,
providing a better picture of underlining trends (Scheme 1). All
1
new species have been characterised by H, 13C and 77Se NMR
spectroscopy, elemental analysis, and X-ray crystallography.
Synthesis:
E = Se, S, Te
N
N
N
N
R
R
R
R
Base
X
E
X= Cl, BF4
Coordination behaviour:
N
N
R
R
-
MX2
N
N
Se
R
R
R
N
N
M-X
M+
R
R
or
Se
Se
Se
M
X
R
N
N
Monomeric
structure
Rearranged
structure
a. Department of Chemistry, Ghent University, Krijgslaan 281, Building S3, 9000
Ghent, Belgium. Kristof.VanHecke@UGent.be; Steven.Nolan@UGent.be
b. WestCHEM Department of Pure & Applied Chemistry, University of Strathclyde,
295 Cathedral Street, Glasgow, G1 1XL UK. David.Nelson@strath.ac.uk
c. VITO (Flemish Institute for Technological Research), Boeretang 200, 2400 Mol,
Belgium. Fady.Nahra@Vito.be
Scheme 1. Summary of this work
Electronic Supplementary Information (ESI) available: NMR spectra of new
compounds and complexes prepared during this study. See
DOI: 10.1039/x0xx00000x
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Based on previous and current work, single-crystal X-ray
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DOI: 10.1039/D0DT02558E
Se, S or Te (1.1-3 equiv.)
Base (3 equiv.)
analysis is crucial for the elucidation of the solid-state behaviour
of [Se(NHC)] ligands when coordinated to Group 11 metals;
solid state behaviour differs from solution state behaviour
depending on the electronic and steric properties of the parent
NHC. In this context, we have established that two different
structures for Cu(I) and Au(I) complexes of these ligands can be
obtained in the solid-state: i) the (expected) monomeric
[MCl(L)] or ii) rearranged-type [M(L)2][MCl2] structures. The
coordination chemistry of these ligands with Ag(I) is significantly
more complicated; the solid-state behaviour of the obtained
silver complexes is much more sensitive to the steric and
electronic nature of the ligand, and multiple coordination
environments can be observed when different crystals are
picked from the same batch of the product. Work by Ritch and
co-workers has significantly contributed to the understanding
of these silver species.20
N
N
N
N
R
R
R
R
acetone, 60 °C, 16 h
Cl
E
Scheme 2. Weak base approach to synthesising chalcogen-based ureas
only K2CO3 afforded the desired compound, which was obtained
in 78% yield (Table 1, entry 3). Both strategies were then
attempted with the other eight imidazolium salts, and good
yields of all seleno- and thioureas were obtained with a few
exceptions (Table 1, entries 4-20); the triethylamine route did
not prove successful with alkyl N-substituted compounds (for
which the azolium salts have higher pKa values),21 i.e. ICy and
IAd, whilst K2CO3 performed well for ICy but gave low yield for
[Se(IAd)] and no reaction was observed in the case of [S(IAd)]
(Table 1, entries 17-20). It should be noted that all potassium
carbonate reactions were conducted on a 1-2 g scale while the
use of triethylamine was demonstrated on a smaller scale, as
proof-of-concept.
Results and discussion
a
Table 1. Syntheses of NHC-based chalcogens using K2CO3 and NEt3
Synthesis of NHC-based seleno-, thio- and telluroureas
Entry
1
Products
NEt3
K2CO3
A wide range of imidazolium salts having different electronic
and steric properties were used in this report; these are shown
in Figure 1. Using the weak base approach, we attempted the
synthesis of the corresponding seleno-, thio- and telluroureas
via deprotonation of the imidazolium salts in the presence of
1.1 to 3 equiv. of elemental chalcogen (Scheme 2). Two
different weak bases, namely potassium carbonate (K2CO3) and
triethylamine (NEt3), were used for comparison; K2CO3 affords a
heterogeneous reaction mixture, whilst NEt3 delivers a
homogeneous mixture, more suitable for continuous
processing applications. Typically, 1.5 to 3 equiv. of elemental
chalcogen were needed to achieve good yields when using the
K2CO3 route, while only 1.1 equiv. of chalcogen were needed
with NEt3. The attractiveness of these reagents, from a cost and
practicality points of view, has been well-highlighted in previous
studies.19
[Se(IPr)]
82%
80%
2
3
[S(IPr)]
[Te(IPr)]
99%
NR
>99%
78%b
90%c
95%b
NR
4
[Se(SIPr)]
[S(SIPr)]
82%
99%
NR
5
6
[Te(SIPr)]
[Se(IMes)]
[S(IMes)]
[Te(IMes)]
[Se(SIMes)]
[S(SIMes)]
[Te(SIMes)]
[Se(IPrMe)]
[S(IPrMe)]
[Se(IPrCl)]
[S(IPrCl)]
7
82%
86%
NR
94%b
87%b
NR
8
9
8
65%
71%
NR
71%c
86%b
NR
9
10
11
12
13
14
15
16
17
18
19
20
75%
85%
95%
98%
95%
91%
NR
71%b
87%b
82%b
92%b
94%c
95%c
87%c
99%c
12%c
NR
Using these conditions, the syntheses of IPr-based
chalcogens ([Se(IPr)], [S(IPr)] and [Te(IPr)]) were attempted
initially (Table 1). [Se(IPr)] and [S(IPr)] were successfully
accessed in good yields (Table 1, entries 1-2). As for [Te(IPr)],
[Se(IPr*)]
[S(IPr*)]
iPr
iPr
iPr
iPr
N
N
N
N
N
N
[Se(ICy)]
[S(ICy)]
iPr
iPr
iPr
iPr
Cl
IMes·HCl
Cl
IPr·HCl
Cl
SIPr·HCl
NR
[Se(IAd)]
[S(IAd)]
NR
Cl
iPr
Cl
iPr
iPr
iPr
N
N
NR
N
N
N
N
iPr
iPr
IPrMe·HCl
Cl
SIMes·HCl
iPr
IPrCl·HCl
iPr
aReaction conditions: NHC·HX (1 equiv.) + chalcogen (1.1 equiv.) in acetone (0.2 M)
at 60 oC for 16 h. b1.5 equiv. of chalcogen were used. c3 equiv. of chalcogen were
used. All yields are isolated yields. NR = no reaction
Cl
Cl
Ph
Ph
Ph
Ph
N
N
N
N
N
N
Despite the successful synthesis of a range of compounds,
including [Te(IPr)], no other tellurourea compound was
afforded using either strategy; no reaction was observed in all
Cl
Cl
IPr*·HCl
BF4
ICy·HBF4
Ph
Ph
Ph
Ph
IAd·HCl
Figure 1. Imidazolium salts used in this work.
2 | J. Name., 2012, 00, 1-3
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Figure 2. Molecular structures of [S(IPrMe)] (left), [S(ICy)] (middle) and [Se(IPrMe)] (right) determined by single-crystal X-ray diffraction analysis. Most hydrogen atoms and solvent
molecules are omitted for clarity. Thermal displacement ellipsoids are shown at the 50% probability level. Some selected distances for [S(IPrMe)], C1-S1 = 1.677(1) Å; for [S(ICy)];
C1-S1 = 1.692(2) Å; for [Se(IPrMe)]; C1-Se1 = 1.842(3) Å.
attempts to access [Te(SIPr)], [Te(IMes)] and [Te(SIMes)] (Table the presence of either one or several coordination species. This
1, entries 6, 9 and 10). Based on these results, our initial is especially relevant in the case of Ag-coordinated species as
conclusion was to consider the targeted compounds too observed previously; as for Cu- and Au-coordinated species,
unstable to be formed. In that context and to test this results have consistently afforded only one species with
hypothesis, we attempted to synthesise [Te(SIPr)] and different batches of crystals or different crystals within the
[Te(SIMes)] via the free carbene route. Using 1.1 equiv. of Te same batch.
and 1 equiv. of the corresponding free carbenes, the desired Copper: As previously observed,7 the reaction of CuCl with N-
telluroureas were prepared in 84% and 85%, respectively alkyl substituted selenoureas remains unsuccessful, and a
(Scheme 3). This means that the weak base approach, at least mixture of unidentified products is obtained. However, N-aryl
as utilised herein, is not optimal for tellurourea synthesis. substituted selenoureas readily coordinate to CuCl. X-ray
Efforts to fully understand and optimise this reaction are analyses have shown that the copper complexes adopt so far
ongoing in our laboratories.
two main coordination motifs leading to different solid-state
structures, specifically monomeric [CuCl(L)] complexes or
rearranged-type [Cu(L)2][CuCl2] structures (Table 2). It should
be noted that 2D 1H DOSY (Diffusion-Ordered NMR
SpectroscopY) experiments have always shown that this
behaviour is not translated into solution, as only monomeric
structures have been observed in solution. Upon reacting CuCl
separately with [Se(SIPr)] and [Se(IPrMe)], and after work-up,
single crystals were grown by vapor diffusion of pentane into a
saturated solution of the corresponding products in
dichloromethane. All molecular structures are illustrated in
Figure 3.
Te (1.1 equiv.)
N
N
N
N
R
R
R
R
THF, 60 °C, 16 h
Te
[Te(SIPr)], 84%
[Te(SIMes)], 85%
Scheme 3. Synthesis of the telluroureas via the free carbene route
X-ray diffraction analysis was also performed on some of the
new compounds in order to determine their solid-state
structure. Single crystals of previously unreported compounds
([Se(IPrMe)], [S(IPrMe)] and [S(ICy)]) were grown by vapor
diffusion of pentane into a saturated solution of the product in
dichloromethane. All molecular structures are illustrated in
Figure 2. From the obtained X-ray structures, we note that the
Ccarbene-S bond in the thiourea compounds is not influenced by
the substituents on the aryl groups or the ring backbone (when
comparing IMes and IPrMe, C1-S1 distance for both is 1.677 Å).
It varies more with the N-substitution when going from aryl to
alkyl groups as shown by the C1-S1 distance of 1.692(2) Å in
[S(ICy)], and is in agreement with literature values for similar
compounds.22 As for [Se(IPrMe)], the C-Se bond (1.842(3) Å) is
significantly longer than the C-S bond and is in accordance with
previous values.5,18 Unfortunately, no suitable crystals could be
obtained for any of the telluroureas despite numerous
attempts.
Table 2. Overview of previous and current coordination behaviour of selenoureas to CuCl
N
N
R
R
CuCl (2.5 equiv.)
CHCl3, 4 h, r.t.
N
N
R
[Cu{Se(NHC)}2][CuCl2]
R
or
Se
Se
Cu
Cl
Solid-state coordination to CuCl
[Se(NHC)]
[Se(IPr)]a
Monomeric
Rearranged
Yield (%)
[CuCl{Se(IPr)}]
[CuCl{Se(IPr*)}]
-
81
[Se(IPr*)]a
[Se(IMes)]a
[Se(SIMes)]a
[Se(SIPr)]b
[Se(IPrMe)]c
-
70
90
86
86
93
[Cu{Se(IMes)}2][CuCl2]
[Cu{Se(SIMes)}2][CuCl2]
[Cu{Se(SIPr)}2][CuCl2]
-
-
-
[CuCl{Se(IPrMe)}]
Coordination of selenoureas to coinage metals (Cu, Ag and Au)
Reaction conditions: [Se(NHC)] (1 equiv.) + CuCl (2.5 equiv.) in CHCl3 for 4 h. All
yields are isolated yields. aResults taken from reference [7]. bReported previously7
but crystal structure is not yet reported. cNew complex.
The solid-state behaviour and 77Se NMR shift of Cu-, Au- and Ag-
coordinated selenoureas are next discussed. It should be noted
that multiple crystals from each batch were analysed to confirm
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with [Se(IMes)] (180°). The C-Se-Cu angles (1V0ie4w.8A(rt2ic)l°e Oanlninde
105.9(2)°) are also within range of similarDsOtrIu: 1c0t.u10re39s/(D100D2T-01205558°)E.
The C-Se bonds (1.865(5) and 1.867(5) Å) are within the normal
range of similar structures and are only slightly elongated when
compared to the C-Se bond in the corresponding free
selenourea.5 The main structural difference observed for
[Cu{Se(SIPr)}2][CuCl2], when compared to IMes- and SIMes-
rearranged structures, is the significantly elongated Cu-Se bond
(2.2814(8)-2.2797(8) Å vs 2.2636(0) Å for IMes and 2.2685(8)-
2.2684(8) Å for SIMes), probably due to the additional steric
hindrance induced by the SIPr aryl substitution.
As for [CuCl{Se(IPrMe)}], the C-Se and Cu-Se bonds are similar to
previous IPr- and IPr*-based monomeric structures. The
structure also features a bent C-Se-Cu angle (104.22(8)°) within
range of previous structures. However, the Se-Cu-Cl angle
(164.59(3)°) deviates significantly from a linear geometry and
from other monomeric structures (168.21(3)° for IPr and
165.79(3)° for IPr*). This has significant consequences, since
now the distance between copper and the ipso-carbon on the
N-aryl substituent (Cipso-Cu = 2.940(3) Å) is comfortably within
the sum of the van der Waals radii (ca. 3.1 Å), thus indicating a
possible interaction between the two. Thus far, this
phenomenon has only been observed with gold selenourea
complexes in this series.
Gold: Coordination to gold has been much more successful. So
far, we have only reported gold coordination to N-aryl
selenoureas.8 Herein, we extend the N-aryl portfolio to new
selenoureas and further include the successful coordination of
N-alkyl substituted selenoureas to gold(I) chloride using
[AuCl(SMe2)] as the metal precursor (Table 3).
In this manner, N-aryl -[Se(IPrMe)] and [Se(IPrCl)]- and N-alkyl
-[Se(ICy)] and [Se(IAd)]- selenoureas were separately reacted
with [AuCl(SMe2)], and after work up, single crystals of the
previously unreported compounds were grown by vapor
diffusion of pentane into a saturated solution of the
corresponding products in dichloromethane (Table 3 and Figure
4). The corresponding structures were identified as monomeric
for [AuCl{Se(IPrMe)}], [AuCl{Se(IPrCl)}] and AuCl{Se(ICy)}], and as
rearranged for [Au{Se(IAd)}2][AuCl2] (Figure 4). This represents
a clear trend in gold(I) coordination chemistry, as so far only
selenoureas with high -accepting abilities ([Se(SIPr)],
[Se(SIPrOMe)] and [Se(IAd)] with 77Se NMR shift of 190, 185 and
198 ppm, respectively) have led to rearranged structures. In
addition, when we previously investigated the coordination of
Figure 3. Molecular structures of [Cu{Se(SIPr)}2][CuCl2] (top) and [CuCl{Se(IPrMe)}]
(bottom) determined by single-crystal X-ray diffraction analysis. Most hydrogen atoms
and solvent molecules are omitted for clarity. Thermal displacement ellipsoids are shown
at the 50% probability level. See Table 5 for selected bond lengths and angles.
X-ray analysis of the two new species clearly highlights the
difference in behaviour, as two different types of complexes
were obtained (Table 2 and Figure 3); [Se(SIPr)] joins
[Se(SIMes)] and [Se(IMes)] in affording a rearranged structure,
[Cu{Se(SIPr)}2][CuCl2], whilst [Se(IPrMe)] joins [Se(IPr)] and
[Se(IPr*)] in affording a monomeric one, [CuCl{Se(IPrMe)}].
Unfortunately, no clear trend can yet be correlated to the -
accepting ability (or 77Se NMR shift) of the corresponding
selenourea ligands, since both types of behaviour are
manifesting with ligands from across the spectrum. So far, we
can only assert that the monomeric species have only been
observed with mid-range -accepting ligands (δSe = 90-106
ppm). One theory is that the difference in coordination when
comparing SIPr- and IPr-based complexes is due to the clear
difference in -accepting ability (190 vs 90 ppm, respectively).
However SIMes- and IMes-based complexes both give similar
rearranged structures despite their widely different -accepting
abilities (110 vs 27 ppm, respectively) which we propose to be
due to the significantly lower steric demand of IMes and SIMes
versus IPr and SIPr.
[Se(IPrCl)] to gold chloride,
a
rearranged structure,
[Au{Se(IPrCl)}2][AuCl2], was obtained, though it was not suitable
for publication at the time and we were never able to reproduce
it. As a consequence, this result was omitted from these studies.
However, this now offers an insight to the gold trend as we
believe that [Se(IPrCl)] is located at the interface of these two
behaviours; thus, selenoureas with higher -accepting abilities
(δSe > 174 ppm) can be expected to afford rearranged structures
when coordinated to gold(I) chloride.
The Se-Au bond in all three monomeric structures is within
range (2.35-2.36 Å) of previously reported complexes; 2.3614(5)
Å for [AuCl{Se(IPrMe)}], 2.3646(6) Å for [AuCl{Se(IPrCl)}] and
2.3714(6) Å for [AuCl{Se(ICy)}], with a slight elongation in the
The Se-Cu-Se angle in [Cu{Se(SIPr)}2][CuCl2] is 179° (Figure
3), and is in accordance with the analogous structure obtained
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Table 3. Overview of previous and current coordination behaviour of selenoureas to AuCl
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DOI: 10.1039/D0DT02558E
N
N
R
R
[AuCl(SMe2)] (1 equiv.)
acetone, 3 h, r.t.
N
N
R
[Au{Se(NHC)}2][AuCl2]
R
or
Se
Se
Au
Cl
Solid-state coordination to AuCl
[Se(NHC)]
[Se(IPr)]a
Monomeric
Rearranged
Yield
[AuCl{Se(IPr)}]
-
-
99%
[Se(SIPr)]a
[Au{Se(SIPr)}2][AuCl2]
99%
99%
99%
99%
99%
99%
99%
95%
99%
93%
[Se(SIPrOMe)]a
[Se(IPr*)]a
-
[Au{Se(SIPrOMe)}2][AuCl2]
[AuCl{Se(IPr*)}]
[AuCl{Se(IPr*OMe)}]
[AuCl{Se(IMes)}]
[AuCl{Se(SIMes)}]
[AuCl{Se(IPrMe)}]
[AuCl{Se(IPrCl)}]
[AuCl{Se(ICy)}]
-
-
[Se(IPr*OMe)]a
[Se(IMes)]a
[Se(SIMes)]a
[Se(IPrMe)]b
[Se(IPrCl)]c
-
-
-
-
-
[Se(ICy)]b
-
[Se(IAd)]b
[Au{Se(IAd)}2][AuCl2]
Reaction conditions: [Se(NHC)] (1 equiv.) + [AuCl(SMe2)] (1 equiv.) in acetone for 3
h. All yields are isolated yields. aResults taken from reference [8]. bNew complex.
cReported previously8 but crystals were not suitable for publication.
latter case, which is the only N-alkyl based selenourea in this
monomeric series. The C1-Se bond is also within range for the
two N-aryl based complexes; however, [AuCl{Se(ICy)}] presents
a longer bond in comparison (1.889(2) vs 1.874(3) Å and
1.868(3) Å).
All three structures feature a bent C-Se-Au angle with some
noticeable differences (Figure 4). The N-aryl selenoureas,
[AuCl{Se(IPrMe)}] and [AuCl{Se(IPrCl)}], display a slightly larger
angle than all previous complexes in this series; 106.95(9)° and
107.29(9)°, respectively (vs previous range 103.40°-106.94°).
This does not influence the Se-Au-Cl angles which still deviate
from a linear geometry in both complexes but remain within
range of previously reported monomeric gold structures.
The Au-Cipso distances (3.175(3) Å for [AuCl{Se(IPrMe)}] and
3.199(3) Å for [AuCl{Se(IPrCl)}]) are also well within the sum of
the van der Waals radii of the two atoms (ca. 3.36 Å), suggesting
an interaction as in previous gold complexes. In contrast,
[AuCl{Se(ICy)}] deviates somewhat from the norm. It displays
the tightest C-Se-Au angle observed so far (97.38(6)°). The
angled bond is also facing forward and not sideways as
previously observed, most likely due to the absence of the
typical stabilisation brought by the aryl Cipso interaction. Now,
the bent structure tries to minimize steric interactions by
optimising the torsion angle C4-N-Se-Au (89.4(1)°; C4 is the
carbon adjacent to N2). This has significant consequences on
the Se-Au-Cl angle which is now closer to linear geometry
(177.06(2)°, again due to the absence of the aryl Cipso
interaction). Interestingly, new interactions are now observed
between Se1 and both H4 and H10 (2.8121 Å and 2.8102 Å,
respectively); both lengths are well within the sum of the van
der Waals radii of the two atoms (ca. 3.1 Å).
Figure 4. Molecular structures of [AuCl{Se(IPrMe)}] (top), [AuCl{Se(IPrCl)}] (2nd from top),
[AuCl{Se(ICy)}] (3rd from top) and [Au{Se(IAd)}2][AuCl2] (bottom) determined by single-
crystal X-ray diffraction analysis. Most hydrogen atoms and solvent molecules are
omitted for clarity. Thermal displacement ellipsoids are shown at the 50% probability
level. See Table 5 for selected bond lengths and angles.
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Journal Name
Regarding the rearranged [Au{Se(IAd)}2][AuCl2] structure, analogue. However, this new structure differs from the latter as
View Article Online
DOI: 10.1039/D0DT02558E
the Se-Au bonds (2.384(1) Å and 2.387(1) Å) are found to be it possesses an outer sphere [AgCl2] counterion. This now puts
within normal range. Again, elongated C1-Se bonds are found it in the category of rearranged complexes, still with a linear
(1.928(7) Å and 1.920(7) Å; longest in the series) along with cationic structure, and the first observed in this series with
tighter C-Se-Au angles (100.5(2)° and 100.9(2)°). This seems to silver. It should be noted that this structure is now in agreement
be a characteristic of N-alkyl based selenoureas. The Se-Cu-Se with the observations made by Ritch and co-workers,20 further
angle in [Au{Se(IAd)}2][AuCl2] is quite close to linear geometry adding to the complexity of silver coordination behaviour. The
(179.34(4)°), and in accordance with previous rearranged reaction of AgCl with [Se(IPrMe)] was also performed and a new
structures in this series.
complex was obtained as indicated by NMR analysis. Luckily, a
Silver: Coordination to silver has been a much trickier 77Se NMR shift was observed (4.89 ppm); however, we were not
endeavour. Selenourea complexation to silver(I) chloride has able to grow any suitable crystals for X-ray analysis despite
displayed a wide range of behaviours in the solid-state, though numerous attempts.
this series only gave monomeric structures in solution (Table 4).
The Se-Ag bond (2.4812(5) Å and 2.4816(5) Å) in
So far, we have identified four types of coordination [Ag{Se(SIPr)}2][AgCl2] is in the same range as other di-
behaviours: i) The tri-coordinated trigonal planar cationic coordinated linear silver complexes in this series, though
structures, when using relatively small N-alkyl based ligands (i.e. significantly longer than analogous gold (2.36-2.39 Å) and
ItBu and ICy), affording an [Ag{Se(ItBu)}3] core with a [AgCl3] copper (2.26-2.28 Å) complexes (Figure 5 and Table 5). The C1-
counterion or [Ag{Se(ICy)}3] core with a chloride counterion. ii) Se bond (1.863(5) Å and 1.867(5) Å) is also within the norm and
The di-coordinated trigonal planar neutral species, when using does not vary significantly when comparing different coinage
a
larger N-alkyl based ligand (i.e. IDD), affording metal complexes. The rearranged species displays a slightly
[AgCl{Se(IDD)}2]. iii) The di-coordinated linear cationic structure larger C1-Se-Ag angle (105.3(2)° and 104.1(2)°) than all previous
bearing an outer-sphere chloride counterion, when using a linear di-coordinated silver complexes in this series. This does
bulky N-aryl based ligand (i.e. IPr), affording [Ag{Se(IPr)}2]Cl. iv) not influence the Se-Ag-Se angle, which is still quite close to
The dimeric structure with a trigonal planar silver environment, linear geometry (178.89(3)°), and in accordance with previous
characteristic of a smaller N-aryl based ligand (i.e. IMes), rearranged structures in this series.
affording neutral [AgCl{-Se(IMes)}]2 species. At this point, it
The dimeric [AgCl{-Se(SIMes)}]2 presents some interesting
seems that both electronic and steric effects are important and features; each of the Se atoms seems to coordinate to both
are significantly influencing the coordination patterns (Table 4). silver moieties, though not entirely in a symmetrical manner
Based on these observations, the reaction of [Se(SIMes)] (2.7067(3) Å for Se1-Ag1 and 2.6579(4) Å for Se1-Ag2), and not
with AgCl was attempted, expecting a dimeric structure which with similar angles (98.82(7)° for C1-Se1-Ag1 and 107.57(7)° for
was observed after X-ray analysis (Figure 5). In that manner, C1-Se1-Ag2). Yet, this is still in agreement with previous results
[AgCl{-Se(SIMes)}]2 was obtained in a similar structure to the obtained with the IMes analogue, and with reports by Ritch and
IMes-analogue. The reaction of [Se(SIPr)] with AgCl was also co-workers on similar compounds.
performed, leading to the expected di-coordinated linear
cationic structure, [Ag{Se(SIPr)}2][AgCl2], similarly to the IPr-
Table 4. Overview of previous and current coordination behaviour of selenoureas to AgCl
AgCl (2 equiv.)
N
N
Various solid-state
coordination behaviours
R
R
CHCl3, r.t., ON
Se
Solid-state coordination to AgCl
[Se(NHC)]
Dimeric
Rearranged
di-coordinated
[Ag{Se(IPr)}2]Cl
Tri-coordinated
Yield (%)
89
98
[Se(IPr)]a
-
-
[Ag{Se(IPr)}2][NO3]b
-
[Se(IMes)]a
[Se(ItBu)]a
[Se(ICy)]a
-
-
-
-
-
-
87
83
78
93
93
94
98
[AgCl{-Se(IMes)}]2
-
-
[Ag{Se(ItBu)}3][0.5{AgCl3}]
-
-
[Ag{Se(ICy)}3]Clc
[Se(IDD)]a
[Se(SIPr)]d
[Se(SIMes)]d
[Se(IPrMe)]d
-
[AgCl{Se(IDD)}2]
-
-
-
-
[Ag{Se(SIPr)}2][AgCl2]
-
-
-
[AgCl{-Se(SIMes)}]2
No crystals obtained
Reaction conditions: [Se(NHC)] (1 equiv.) + AgCl (2 equiv.) in CHCl3 overnight. All yields are isolated yields. aResults taken from reference [7]. bAgNO3 was used instead of
AgCl. cA different coordination behaviour was observed in the same crystal batch and [(Ag{Se(ICy)}2)2{µ-Se(ICy)}][NO3]2 was identified by X-ray analysis.7 dNew complexes.
6 | J. Name., 2012, 00, 1-3
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correlation between δSe for the selenourea ligands and δSe for
View Article Online
DOI: 10.1039/D0DT02558E
the corresponding metal complexes is now updated with the
newly obtained values, and the corrected trends are shown in
Figure 7.
Conclusions
In summary, we describe in this report the synthesis and
characterisation of new chalcogen-based urea compounds
bearing a wide range of N-heterocylic carbenes. A “weak base”
approach has been investigated using either NEt3 or K2CO3 as
base, and good to excellent yields were obtained overall.
Coordination of selenoureas is further investigated with Group
11 transition metals (i.e. copper(I), gold(I) and silver(I)),
affording new copper, gold and silver complexes. Single crystal
X-ray analysis was used to elucidate the solid-state coordination
behaviour of these complexes in an attempt to establish a
correlation between the latter and their corresponding
electronic and steric properties. We showed that the geometry
of a complex is highly influenced by a combination of electronic
properties -mainly -accepting ability- and steric hindrance of
the ligands, as well as the nature of the metal, affording a
variety of coordination behaviours. Ultimately, we believe that
understanding these behaviours, through future in-depth
studies, would allow us better prediction tools.
Figure 5. Molecular structures of [Ag{Se(SIPr)}2][AgCl2] (top) and [AgCl{-Se(SIMes)}]2
(bottom) determined by single-crystal X-ray diffraction analysis. Most hydrogen atoms
and solvent molecules are omitted for clarity. Thermal displacement ellipsoids are shown
at the 50% probability level. See Table 5 for selected bond lengths and angles.
Experimental
Table 5. Selected bond lengths and angles for the newly synthesised complexes
NMR spectra were acquired on a Bruker AV3-400 spectrometer
equipped with a liquid nitrogen cryoprobe, a Bruker AV400
spectrometer with a BBFO-z-ATMA probe or a Bruker Avance II
500MHz equipped with a 5mm triple channel probe head (TXO
Se-M
dist.
2.2814(8)
2.2797(8)
C1-Se
dist.
1.865(5)
1.867(5)
C1-Se-M
angles
104.8(2)
105.9(2)
Se-M-X
anglea
Structure
[Cu{Se(SIPr)}2][CuCl2]
179.28(4)
1
type). H NMR spectra were referenced to residual solvent
[CuCl{Se(IPrMe)}]
[AuCl{Se(IPrMe)}]
[AuCl{Se(IPrCl)}]
[AuCl{Se(ICy)}]
2.2596(4)
2.3614(5)
2.3646(6)
2.3714(6)
1.865(3)
1.874(3)
1.868(3)
1.889(2)
104.22(8)
106.95(9)
107.29(9)
97.38(6)
164.59(3)
172.30(3)
174.00(3)
177.06(2)
signals and 13C{1H} DEPT Q NMR spectra to the deuterated
solvent signal, while chemical shifts are reported in ppm. 77Se
1
NMR spectra were referenced to external standards. [1H, H]
COSY, [1H, 13C] HSQC and [1H, 13C] HMBC spectra were used to
assign signals. X-ray intensity data were collected at 100 K, on a
Rigaku Oxford Diffraction Supernova Dual Source (Cu at zero)
diffractometer equipped with an Atlas CCD detector using 
scans and Cu K ( = 1.54184 Å) or Mo K ( = 0.71073 Å)
radiation. The images were interpreted and integrated with the
program CrysAlisPro.23 Using Olex2,24 the structures were
solved by direct methods using the ShelXS/T structure solution
program and refined by full-matrix least-squares on F2 using the
ShelXL program package.25,26 Non-hydrogen atoms were
anisotropically refined and the hydrogen atoms in the riding
mode with isotropic temperature factors fixed at 1.2 times
U(eq) of the parent atoms (1.5 times for methyl groups). Sulfur,
selenium, tellurium, AgCl, CuCl, triethylamine and potassium
carbonate were obtained from commercial sources and used as
supplied. [AuCl(SMe2)] is prepared according to a known
procedure.27 Reagent grade solvents were always used as
received unless otherwise stated. When the free carbene route
was used for tellurourea synthesis, reactions were performed in
an Argon-filled glovebox using anhydrous solvents.
2.384(1)
2.387(1)
2.4812(5)
2.4816(5)
1.920(7)
1.928(7)
1.863(5)
1.867(5)
100.5(2)
100.9(2)
105.3(2)
104.1(2)
98.82(7)d
[Au{Se(IAd)}2][AuCl2]
[Ag{Se(SIPr)}2][AgCl2]
[AgCl{-Se(SIMes)}]2
179.34(4)
178.89(3)
123.93(2)
2.7067(3)b 1.868(3)
2.6579(4)c 1.868(3) 107.57(7)e 126.93(2)
Distances are in (Å) and angles are in (°). aX = Cl or Se depending on coordination.
bSe1-Ag1 bond distance. cSe1-Ag2 bond distance. dC1-Se1-Ag1 angle. eC1-Se1-Ag2
angle.
77Se NMR: Next, we attempted to record the 77Se spectra for all
newly synthesised coinage-metal selenourea complexes (Figure
6). Of the nine complexes herein reported, only five showed
clear signals in the 77Se spectrum (two silver and three gold
selenourea complexes). The 77Se resonances are typically very
weak for the coordinated complexes, and extended analyses
are required, even on a cryoprobe-equipped spectrometer; the
copper and silver complexes were particularly challenging to
analyse and, despite numerous attempts, none of the new
copper complexes showed any 77Se NMR signals. The linear
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DOI: 10.1039/D0DT02558E
Figure 6. Overview of previous and current (values in red) chemical shifts of selenourea ligands, and their copper, silver, and gold complexes. All NMR data were acquired at 300 K
in chloroform-d solution.
General procedure for the synthesis of chalcogenoureas
[Se(IPr)]
Method 1: IPr·HCl (2 g, 4.70 mmol), K2CO3 (1.95 g, 14.12 mmol,
3 equiv.) and selenium (0.408 g, 5.18 mmol, 1.1 equiv.) were
mixed together in acetone (20 mL) in a vial provided with a
o
stirring bar. The mixture was stirred at 60 C for 16 h. The
solvent was evaporated and the residue was filtered through
silica using DCM which was then evaporated to yield a white
powder. Yield: 1.76 g, 3.76 mmol, 80%.
Method 2: IPr·HCl (100 mg, 0.24 mmol), NEt3 (0.098 mL, 0.71
mmol, 3 equiv.) and selenium (20.4 mg, 0.26 mmol, 1.1 equiv.)
were mixed together in acetone (1 mL) in a vial equipped with
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The
solvent was evaporated and the residue was filtered through
silica using DCM which was then evaporated to yield a white
1
powder. Yield: 90.2 mg, 0.19 mmol, 82%. H NMR (CDCl3, 400
MHz): δH 7.48 (t, J = 8 Hz 2H, Ar CH), 7.31 (d, J = 7.8 Hz, 4H, Ar
CH), 7.01 (s, 2H, N(CH)2N), 2.69 (sept, J = 6.9 Hz, 4H, CHMe2),
1.34 (d, J = 6.9 Hz, 12H, CH3), 1.20 (d, J = 6.9 Hz, 12H, CH3).
13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 162.3 (C=Se), 146.3
(Ar C), 134.5 (Ar C), 130.3 (Ar CH), 124.4 (Ar CH), 121.2
(N(CH)2N), 29.1 (CHMe2), 24.5 (CH3), 23.5 (CH3). The data
obtained matched the reported values.28
Figure 7. Updated plot of δSe for copper, silver, and gold complexes of selenourea ligands
versus δSe of the corresponding ligand. Dots in red circles represent the new additions to
[S(IPr)]
Method 1: IPr·HCl (2 g, 4.70 mmol), K2CO3 (1.95 g, 14.12 mmol,
this series.
3 equiv.) and sulfur (0.166 g, 5.18 mmol, 1.1 equiv.) were mixed
8 | J. Name., 2012, 00, 1-3
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together in acetone (20 mL) in a vial equipped with a stirring (CHMe2), 24.9 (CH3), 24.5 (CH3). The data obtainedVmiewaAtcrthicleedOntlhinee
bar. The mixture was stirred at 60 oC for 16 h. The solvent was reported values.9
DOI: 10.1039/D0DT02558E
evaporated and the residue was filtered through silica using
DCM which was then evaporated to yield a white powder. Yield: [S(SIPr)]
1.96 g, 4.66 mmol, 99%.
Method 1: SIPr·HCl (2 g, 4.68 mmol), K2CO3 (1.94 g, 14.05 mmol,
Method 2: IPr·HCl (100 mg, 0.24 mmol), NEt3 (0.098 mL, 0.071 3 equiv.) and sulfur (0.225 g, 7.02 mmol, 1.5 equiv.) were mixed
mmol, 3 equiv.) and sulfur (8.3 mg, 0.259 mmol, 1.1 equiv.) together in acetone (20 mL) in a vial equipped with a stirring
were mixed together in acetone (1 mL) in a vial equipped with bar. The mixture was stirred at 60 oC for 16 h. The solvent was
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The evaporated and the residue was filtered through silica using
solvent was evaporated and the residue was filtered through DCM which was then evaporated to yield a white powder. Yield:
silica using DCM which was then evaporated to yield a white 1.88 g, 4.45 mmol, 95%.
1
powder. Yield: 97.9 mg, 0.23 mmol, 99%. H NMR (CDCl3, 400 Method 2: SIPr·HCl (100 mg, 0.234 mmol), NEt3 (0.097 mL, 0.702
MHz): δH 7.46 (t, J = 8 Hz, 2H, Ar CH), 7.30 (d, J = 7.8 Hz, 4H, Ar mmol, 3 equiv.) and sulfur (8.3 mg, 0.258 mmol, 1.1 equiv.)
CH), 6.84 (s, 2H, N(CH)2N), 2.76 (sept, J = 6.9 Hz, 4H, CHMe2), were mixed together in acetone (1 mL) in a vial equipped with
o
1.32 (d, J = 6.9 Hz, 12H, CH3), 1.22 (d, J = 6.9 Hz, 12H, CH3). a stirring bar. The mixture was stirred at 60 C for 16 h. The
13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 167.2 (C=S), 146.6 solvent was evaporated and the residue was filtered through
(Ar C), 133.9 (Ar C), 130.1 (Ar CH), 124.3 (Ar CH), 119.1 silica using DCM which was then evaporated to yield a white
(N(CH)2N), 29.0 (CHMe2), 24.3 (CH3), 23.5 (CH3). The data powder. Yield: 108.2 mg, 0.256 mmol, 99%. 1H NMR (CDCl3, 400
obtained matched the reported values.29
MHz): δH 7.39 (t, J = 8 Hz, 2H, Ar CH), 7.24 (d, J = 7.7 Hz, 4H,
ArCH), 4.03 (s, 4H, N(CH2)2N), 3.08 (sept., J = 6.9 Hz, 4H, CHMe2),
1.35 (d, J = 6.8 Hz, 12H, CH3), 1.32 (d, J = 7 Hz, 12H, CH3). 13C{1H}
[Te(IPr)]
IPr·HCl (100 mg, 0.24 mmol), K2CO3 (97.6 mg, 0.71 mmol, 3 DEPT Q NMR (CDCl3, 101 MHz): δC 184.5 (C=S), 147.6 (Ar C),
equiv.) and tellurium (45.0 mg, 0.35 mmol, 1.5 equiv.) were 134.9 (Ar C), 129.6 (Ar CH), 124.5 (Ar CH), 50.4 (N(CH2)2N), 29.2
mixed together in acetone (20 mL) in a vial equipped with a (CHMe2), 24.7 (CH3), 24.5 (CH3). The data obtained matched the
stirring bar. The mixture was stirred at 60 C for 16 h. The reported values.30
o
solvent was evaporated and the residue was filtered through
Celite using DCM which was then evaporated to yield a greyish [Se(IMes)]
1
powder. Yield: 94.7 mg, 0.18 mmol, 78%. H NMR (CDCl3, 400 Method 1: IMes·HCl (2 g, 5.87 mmol), K2CO3 (2.432 g, 17.60
MHz): δH 7.51 (t, J = 8 Hz, 2H, Ar CH), 7.32 (d, J = 7.8 Hz, 4H, Ar mmol, 3 equiv.) and selenium (0.694 g, 8.80 mmol, 1.5 equiv.)
CH), 7.20 (s, 2H, N(CH)2N), 2.59 (sept, J = 6.9 Hz, 4H, CHMe2), were mixed together in acetone (20 mL) in a vial equipped with
o
1.38 (d, J = 6.8 Hz, 12H, CH3), 1.18 (d, J = 6.9 Hz, 12H, CH3). a stirring bar. The mixture was stirred at 60 C for 16 h. The
13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 146.0 (C=Te), 138.1 solvent was evaporated and the residue was filtered through
(Ar C), 135.6 (Ar C), 130.6 (Ar CH), 124.5 (Ar CH), 123.5 silica using DCM which was then evaporated to yield an off-
(N(CH)2N), 29.7 (CHMe2), 24.7 (CH3), 23.5 (CH3). The data white powder. Yield: 2.114 g, 5.514 mmol, 94%.
obtained matched the reported values.18
Method 2: IMes·HCl (100 mg, 0.293 mmol), NEt3 (0.122 mL, 0.88
mmol, 3 equiv.) and selenium (25.48 mg, 0.323 mmol, 1.1
equiv.) were mixed together in acetone (1 mL) in a vial equipped
[Se(SIPr)]
Method 1: SIPr·HCl (2 g, 4.68 mmol), K2CO3 (1.94 g, 14.05 mmol, with a stirring bar. The mixture was stirred at 60 oC for 16 h. The
3 equiv.) and selenium (1.109 g, 14.05 mmol, 3 equiv.) were solvent was evaporated and the residue was filtered through
mixed together in acetone (20 mL) in a vial equipped with a silica using DCM which was then evaporated to yield an off-
o
stirring bar. The mixture was stirred at 60 C for 16 h. The white powder. Yield: 92.2 mg, 0.241 mmol, 82%. 1H NMR (CDCl3,
solvent was evaporated and the residue was filtered through 400 MHz): δH 7.02 (s, 4H, Ar CH), 6.96 (s, 2H, N(CH)2N), 2.35 (s,
silica using DCM which was then evaporated to yield a white 6H, CH3), 2.13 (s, 12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101
powder. Yield: 1.98 g, 4.22 mmol, 90%.
MHz): δC 157.8 (C=Se), 139.6 (Ar C), 135.5 (Ar C), 134.4 (Ar C),
Method 2: SIPr·HCl (100 mg, 0.23 mmol), NEt3 (0.097 mL, 0.70 129.4 (Ar CH), 120.3 (N(CH)2N), 21.3 (CH3), 18.2 (CH3). The data
mmol, 3 equiv.) and selenium (20.3 mg, 0.26 mmol, 1.1 equiv.) obtained matched the reported values.8
were mixed together in acetone (1 mL) in a vial equipped with
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The [S(IMes)]
solvent was evaporated and the residue was filtered through Method 1: IMes·HCl (2 g, 5.87 mmol), K2CO3 (2.432 g, 17.60
silica using DCM which was then evaporated to yield a white mmol, 3 equiv.) and sulfur (0.282 g, 8.80 mmol, 1.5 equiv.) were
powder. Yield: 99.7 mg, 0.212 mmol, 82%. 1H NMR (CDCl3, 400 mixed together in acetone (20 mL) in a vial equipped with a
o
MHz): δH 7.40 (t, J = 8 Hz, 2H, Ar CH), 7.24 (d, J = 8 Hz, 4H, Ar stirring bar. The mixture was stirred at 60 C for 16 h. The
CH), 4.03 (s, 4H, N(CH2)2N), 3.06 (sept., J = 6.9 Hz, 4H, CHMe2), solvent was evaporated and the residue was filtered through
1.39 (d, J = 6.8 Hz, 12H, CH3), 1.32 (d, J = 7 Hz, 12H, CH3). 13C{1H} silica using DCM which was then evaporated to yield a greyish
DEPT Q NMR (CDCl3, 101 MHz): δC 184.3 (C=Se), 147.3 (Ar C), powder. Yield: 1.728 g, 5.139 mmol, 87%.
135.4 (Ar C), 129.5 (Ar CH), 124.6 (Ar CH), 51.5 (N(CH2)2N), 29.3 Method 2: IMes·HCl (100 mg, 0.293 mmol), NEt3 (0.122 mL,
0.880 mmol, 3 equiv.) and sulfur (10.3 mg, 0.322 mmol, 1.1
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equiv.) were mixed together in acetone (1 mL) in a vial equipped a stirring bar. The mixture was stirred at 60 C for 16 h. The
View Article Online
with a stirring bar. The mixture was stirred at 60 oC for 16 h. The solvent was evaporated and the residue was filtered through
DOI: 10.1039/D0DT02558E
solvent was evaporated and the residue was filtered through silica using DCM which was then evaporated to yield a white
silica using DCM which was then evaporated to yield a greige powder. Yield: 0.969 g, 1.955 mmol, 89%.
powder. Yield: 84.8 mg, 0.252 mmol, 86%. 1H NMR (CDCl3, 400 Method 2: IPrMe·HCl (20 mg, 0.044 mmol), NEt3 (0.019 mL, 0.132
MHz): δH 7.01 (s, 4H, Ar CH), 6.79 (s, 2H, N(CH)2N), , 2.34 (s, 6H, mmol, 3 equiv.) and selenium (3.8 mg, 0.049 mmol, 1.1 equiv.)
CH3), 2.15 (s, 12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): were mixed together in acetone (1 mL) in a vial equipped with
δC 163.6 (C=S), 139.4 (Ar C), 135.9 (Ar C), 133.8 (Ar C), 129.4 (Ar a stirring bar. The mixture was stirred at 60 C for 16 h. The
CH), 118.2 (N(CH)2N), 21.3 (CH3), 18.0 (CH3). The data obtained solvent was evaporated and the residue was filtered through
matched the reported values.31
silica using DCM which was then evaporated to yield a white
powder. Yield: 16.4 mg, 0.033 mmol, 75%. 1H NMR (CDCl3, 400
MHz): δH 7.48 (t, J = 8 Hz, 2H, Ar CH), 7.31 (d, J = 7.8 Hz, 4H, Ar
[Se(SIMes)]
Method 1: SIMes·HCl (2 g, 5.833 mmol), K2CO3 (2.418 g, 17.50 CH), 2.61 (sept., J = 6.9 Hz, 4H, CHMe2), 1.94 (s, 6H, CH3(imid)),
mmol, 3 equiv.) and selenium (1.382 g, 17.50 mmol, 3 equiv.) 1.36 (d, J = 6.8 Hz, 12H, CH(CH3)2), 1.21 (d, J = 6.9 Hz, 12H,
were mixed together in acetone (20 mL) in a vial equipped with CH(CH3)2). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 159.5
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The (C=Se), 146.5 (Ar C), 132.8 (Ar C), 130.2 (CCH3(imid)), 124.5 (Ar
solvent was evaporated and the residue was filtered through CH), 124.3 (Ar CH), 29.2 (CHMe2), 24.4 (CH3), 24.0 (CH3), 10.5
silica using DCM which was then evaporated to yield an off- (CH3(imid)). 77Se NMR (CDCl3, 76MHz): δSe 105.2. CHN Calculated
white powder. Yield: 1.596 g, 4.142 mmol, 71%.
for C29H40N2Se: C, 70.28; H, 8.14; N, 5.65. Found: C, 69.78; H,
Method 2: SIMes·HCl (100 mg, 0.292 mmol), NEt3 (0.12 mL, 8.43; N, 5.98.
0.875 mmol, 3 equiv.) and selenium (25.3 mg, 0.321 mmol, 1.1
equiv.) were mixed together in acetone (1 mL) in a vial equipped [S(IPrMe)]
with a stirring bar. The mixture was stirred at 60 oC for 16 h. The Method 1: IPrMe·HCl (1.00 g, 2.207 mmol), K2CO3 (0.915 g, 6.62
solvent was evaporated and the residue was filtered through mmol, 3 equiv.) and sulfur (0.106 g, 3.31 mmol, 1.5 equiv.) were
silica using DCM which was then evaporated to yield an off- mixed together in acetone (20 mL) in a vial equipped with a
o
white powder. Yield: 73.1 mg, 0.190 mmol, 65%. 1H NMR stirring bar. The reaction was stirred at 60 C for 16 h. the
(CDCl3, 400 MHz): δH 6.98 (s, 4H, Ar C–H), 4.00 (s, 4H, N(CH2)2N), solvent was evaporated and the residue was filtered through
2.32 (s, 12H, CH3), 2.31 (s, 6H, CH3). 13C{1H} DEPT Q NMR (CDCl3, silica using DCM which was then evaporated to yield a white
101 MHz): δC 180.3 (C=S), 138.6 (Ar C), 136.4 (Ar C), 135.1 (Ar powder. Yield: 0.861 g, 1.92 mmol, 87%.
C), 129.7 (Ar CH), 48.9 (N(CH2)2N), 21.3 (CH3), 18.0 (CH3). The Method 2: IPrMe·HCl (20.0 mg, 0.044 mmol), NEt3 (0.019 mL,
data obtained matched the reported values.8
0.132 mmol, 3 equiv.) and sulfur (1.6 mg, 0.049 mmol, 1.1
equiv.) were mixed together in acetone (1 mL) in a vial equipped
with a stirring bar. The mixture was stirred at 60 oC for 16 h. The
[S(SIMes)]
Method 1: SIMes·HCl (2 g, 5.833 mmol), K2CO3 (2.418 g, 17.4978 solvent was evaporated and the residue was filtered through
mmol, 3 equiv.) and sulfur (0.280 g, 8.749 mmol, 1.5 equiv.) silica using DCM which was then evaporated to yield a white
were mixed together in acetone (20 mL) in a vial equipped with powder. Yield: 16.8 mg, 0.038 mmol, 85%. 1H NMR (CDCl3, 400
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The MHz): δH 7.46 (t, J = 8 Hz, 2H, Ar CH), 7.30 (d, J = 7.7 Hz, 4H, Ar
solvent was evaporated and the residue was filtered through CH), 2.67 (sept., J = 6.9 Hz, 4H, CHMe2), 1.89 (s, 6H, CH3(imid)),
silica using DCM which was then evaporated to yield a greyish 1.32 (d, J = 6.8 Hz, 12H, CH(CH3)2), 1.22 (d, J = 6.7 Hz, 12H,
powder. Yield: 1.698 g, 5.016 mmol, 86%.
CH(CH3)2). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 165.2
Method 2: SIMes·HCl (100 mg, 0.292 mmol), NEt3 (0.12 mL, (C=S), 146.9 (Ar C), 132.2 (Ar C), 130.0 (CCH3(imid)), 124.6 (Ar CH),
0.875 mmol, 3 equiv.) and sulfur (10.3 mg, 0.321 mmol, 1.1 121.9 (Ar CH) 29.1 (CHMe2), 24.4 (CH3), 23.9 (CH3), 10.28
equiv.) were mixed together in acetone (1 mL) in a vial equipped (CH3(imid)). CHN Calculated for C29H40N2S: C, 77.63; H, 8.99; N,
with a stirring bar. The mixture was stirred at 60 oC for 16 h. The 6.24. Found: C, 77.51; H, 8.81; N, 6.24.
solvent was evaporated and the residue was filtered through
silica using DCM which was then evaporated to yield a greige [Se(IPrCl)]
powder. Yield: 70.1 mg, 0.207 mmol, 71%. 1H NMR (CDCl3, 400 Method 1: IPrCl·HCl (1.00 g, 2.025 mmol), K2CO3 (0.839 g, 6.074
MHz): δH 6.97 (s, 4H, Ar CH), 4.00 (s, 4H, N(CH2)2N), 2.32 (s, 12H, mmol, 3 equiv.) and selenium (0.239 g, 3.037 mmol, 1.5 equiv.)
CH3), 2.30 (s, 6H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): were mixed together in acetone (9 mL) in a vial equipped with
o
δC 181.2 (C=S), 138.4 (Ar C), 136.7 (Ar C), 134.7 (Ar C), 129.6 (Ar a stirring bar. The mixture was stirred at 60 C for 16 h. The
CH), 47.7 (N(CH2)2N), 21.3 (CH3), 17.9 (CH3). The data obtained solvent was evaporated and the residue was filtered through
matched the reported values.32
silica using DCM which was then evaporated to yield a white
powder. Yield: 0.891 g, 1.660 mmol, 82%.
[Se(IPrMe)]
Method 2: IPrCl·HCl (100 mg, 0.205 mmol), NEt3 (0.084 mL, 0.607
Method 1: IPrMe·HCl (1.00 g, 2.207 mmol), K2CO3 (0.915 g, 6.621 mmol, 3 equiv.) and selenium (17.6 mg, 0.222 mmol, 1.1 equiv.)
mmol, 3 equiv.) and selenium (0.261 g, 3.310 mmol, 1.5 equiv.) were mixed together in acetone (1 mL) in a vial equipped with
o
were mixed together in acetone (20 mL) in a vial equipped with a stirring bar. The mixture was stirred at 60 C for 16 h. The
10 | J. Name., 2012, 00, 1-3
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solvent was evaporated and the residue was filtered through [S(IPr*]
silica using DCM which was then evaporated to yield a white Method 1: IPr*·HCl (1.00 g, 1.05 mmol), K2CO3 (0.437 g, 3.16
powder. Yield: 104.2 mg, 0.194 mmol, 95%. 1H NMR (CDCl3, 400 mmol, 3 equiv.) and sulfur (0.101 g, 3.16 mmol, 3 equiv.) were
MHz): δH 7.54 (t, J = 7.8 Hz, 2H, Ar CH), 7.34 (d, J = 7.8 Hz, 4H, Ar mixed together in acetone (5 mL) in a vial equipped with a
ARTICLE
View Article Online
DOI: 10.1039/D0DT02558E
o
CH), 2.62 (sept., J = 6.9 Hz, 4H, CHMe2), 1.35 (d, J = 6.8 Hz, 12H, stirring bar. The reaction was stirred at 60 C for 16 h. the
CH3), 1.26 (d, J = 6.9 Hz, 12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, solvent was evaporated and the residue was filtered through
101 MHz): δC 162.2 (C=Se), 146.9 (Ar C), 131.4 (Ar CH), 131.2 (Ar silica using DCM which was then evaporated to yield a white
C), 124.6 (Ar CH), 115.5 (N(CCl)2N), 29.6 (CHMe2), 24.0 (CH3), powder. Yield: 0.945 g, 0.999 mmol, 95%.
24.0 (CH3). The data obtained matched the reported values.8
Method 2: IPr*·HCl (100 mg, 0.105 mmol), NEt3 (0.044 mL, 0.316
mmol, 3 equiv.) and sulfur (3.7 mg, 0.116 mmol, 1.1 equiv.)
[S(IPrCl)]
were mixed together in acetone (1 mL) in a vial equipped with
o
Method 1: IPrCl·HCl (1 g, 2.024 mmol), K2CO3 (0.839 g, 6.072 a stirring bar. The mixture was stirred at 60 C for 16 h. The
mmol, 3 equiv.) and sulfur (0.0974 g, 3.037 mmol, 1.5 equiv.) solvent was evaporated and the residue was filtered through
were mixed together in acetone (20 mL). The reaction was silica using DCM which was then evaporated to yield a white
stirred at 60 oC for 16 h. The solvent was evaporated and the powder. Yield: 90.5 mg, 0.096 mmol, 91%. 1H NMR (CDCl3, 400
residue was filtered through silica using DCM which was then MHz): δH 7.32 (d, J = 7,2 Hz, 8H, Ar CH), 7.22-7.1 (m, 24H, Ar CH),
evaporated to yield a white powder. Yield: 0.8612 g, 1.919 6.86-6.83 (m, 12H, Ar CH), 5.46 (s, 4H, CH(Ph)2), 5.29 (s, 2H,
mmol, 87%.
N(CH2)2N), 2.22(s, 6H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101
Method 2: IPrCl·HCl (100 mg, 0.205 mmol), NEt3 (0.084 mL, MHz): δC 165.6 (C=S), 143.7 (Ar C), 142.9 (Ar C), 141.8 (Ar C),
0.6073 mmol, 3 equiv.) and sulfur (7.2 mg, 0.225 mmol, 1.1 139.4 (Ar C), 133.3 (Ar C), 130.4 (Ar C), 130.1 (Ar CH), 129.5 (Ar
equiv.) were mixed together in acetone (1 mL) in a vial equipped CH), 128.4 (Ar CH), 128.2 (Ar CH), 126.5 (Ar CH), 126.4 (Ar CH),
with a stirring bar. The mixture was stirred at 60 oC for 16 h. The 118.9 (CHimid), 51.8 (CHPh2), 22.0 (CH3). The data obtained
solvent was evaporated and the residue was filtered through matched the reported values.33
silica using DCM which was then evaporated to yield a white
powder. Yield: 98.1 mg, 0.200 mmol, 98%. 1H NMR (CDCl3, 400 [Se(ICy)]
MHz): δH 7.52 (t, J = 7.8 Hz, 2H, Ar CH), 7.33 (d, J = 7.8 Hz, 4H, Ar ICy·HBF4 (1.00 g, 3.12 mmol), K2CO3 (1.30 g, 9.37 mmol, 3 equiv.)
CH), 2.67 (sept., J = 6.8 Hz, 4H, CHMe2), 1.31 (d, J = 6.8 Hz, 12H), and selenium (0.740 g, 9.37 mmol, 3 equiv.) were mixed
1.27 (d, J = 6.9 Hz, 12H). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): together in acetone (14 mL) in a vial equipped with a stirring
δC 166.3 (C=S), 147.2 (Ar C), 131.0 (Ar C), 130.6 (Ar CH), 124.5 bar. The mixture was stirred at 60 oC for 16 h. The solvent was
(Ar CH), 113.6 (N(CCl)2N), 29.5 (CHMe2), 24.0(CH3), 24.0 (CH3). evaporated and the residue was filtered through silica using
CHN Calculated for C27H34N2Cl2S: C, 66.24; H, 7.00; N, 5.72. DCM which was then evaporated to yield a white powder. Yield:
Found: C, 66.24; H, 7.14; N, 6.35.
0.846 g, 2.72 mmol, 87%. 1H NMR (CDCl3, 400 MHz): δH 6.88 (s,
2H, N(CH)2N), 4.88 (tt, 2H, J = 11.8, 3.8 Hz, NCH), 2.12–2.08 (m,
4H, CH2), 1.88–1.84 (m, 4H, CH2), 1.76–1.73 (m, 2H, CH2), 1.53–
[Se(IPr*)]
Method 1: IPr*·HCl (1.00 g, 1.05 mmol), K2CO3 (0.437 g, 3.16 1.36 (m, 8H, CH2), 1.24–1.14 (m, 2H, CH2). 13C{1H} DEPT Q NMR
mmol, 3 equiv.) and selenium (0.249 g, 3.16 mmol, 3 equiv.) (CDCl3, 101 Hz): δC 153.3 (C=Se), 115.8 (N(CH)2N), 58.0 (NCH),
were mixed together in acetone (20 mL) in a vial equipped with 32.7 (CH2), 25.5 (CH2), 25.5 (CH2). The data obtained matched
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The the reported values.6
solvent was evaporated and the residue was filtered through
silica using DCM which was then evaporated to yield a white [S(ICy)]
powder. Yield: 0.982 g, 0.989 mmol, 94%.
ICy·HBF4 (1.00 g, 3.12 mmol), K2CO3 (1.30 g, 9.37 mmol, 3 equiv.)
Method 2: IPr*·HCl (100 mg, 0.105 mmol), NEt3 (0.044 mL, 0.316 and sulfur (0.300 g, 9.37 mmol, 3 equiv.) were mixed together
mmol, 3 equiv.) and selenium (9.2 mg, 0.116 mmol, 1.1 equiv.) in acetone (13.6 mL) in a vial equipped with a stirring bar. The
were mixed together in acetone (1 mL) in a vial equipped with reaction was stirred at 60 oC for 16 h. The solvent was
o
a stirring bar. The mixture was stirred at 60 C for 16 h. The evaporated and the residue was filtered through silica using
solvent was evaporated and the residue was filtered through DCM which was then evaporated to yield a white powder. Yield:
silica using DCM which was then evaporated to yield a white 0.86 g, 3.2 mmol, 99%. 1H NMR (CDCl3, 400 MHz): δH 6.72 (s, 2H,
powder. Yield: 99.3 mg, 0.100 mmol, 95%. 1H NMR (CDCl3, 400 N(CH)2N), 4.88 (tt, 2H, J = 11.8, 3.8 Hz, NCH), 2.08–2.05 (m, 4H,
MHz): δH 7.39-7.37 (m, 8H, Ar C-H), 7.22-7.08 (m, 20H, Ph), 6.85- CH2), 1.87–1.83 (m, 4H, CH2), 1.75–1.72 (m, 2H, CH2), 1.51–1.34
6.81 (m, 12H, Ar CH), 5.42 (s, 4H, CH(Ph)2), 5.37 (s, 2H, (m, 8H, CH2), 1.24–1.12 (m, 2H, CH2). 13C{1H} DEPT Q NMR
N(CH2)2N), 2.22(s, 6H, Me). 13C{1H} DEPT Q NMR (CDCl3, 101 (CDCl3, 101 MHz): δC 160.0 (C=S), 113.8 (N(CH)2N), 55.9 (NCH),
MHz): δC 161.0 (C=S), 143.5 (Ar C), 142.9 (Ar C), 141.7 (Ar C), 32.6 (CH2), 25.6 (CH2), 25.6 (CH2). HRMS m/z calcd for C15H24N2S
139.6 (Ar C), 134.0 (Ar C), 130.5 (Ar C), 130.2 (Ar CH), 129.5 (Ar (M+H+) 265.17; found 265.1741.
CH), 128.3 (Ar CH), 128.2 (Ar CH), 126.6 (Ar CH), 126.4 (Ar CH),
121.0 (CHimid), 51.9 (CHPh2), 22.0 (CH3). The data obtained [Se(IAd)]
matched the reported values.5
IAd·HCl (2.00 g, 5.36 mmol), K2CO3 (2.22 g, 16.09 mmol, 3
equiv.) and selenium (1.270 g, 16.09 mmol, 3 equiv.) were
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mixed together in acetone (24 mL) in a vial equipped with a Hz, 12H, CH3). ). 13C{1H} DEPT Q NMR (CDCl3, 126 MHz): δC
View Article Online
o
stirring bar. The mixture was stirred at 60 C for 16 h. The 152.9 (C=Se), 145.8 (Ar C), 131.9 (Ar CH), 130.9 (CCH3(imid)
DOI: 10.1039/D0D)T,01225568.8E
solvent was evaporated and the residue was filtered through (Ar C), 125.8 (Ar CH), 29.3 (CHMe2), 24.6 (CH3), 24.0 (CH3), 10.4
silica using DCM which was then evaporated to yield a brown (CH3(imid)).
powder. Yield: 0.2673 g, 0.643 mmol, 12%. 1H NMR (300 MHz;
General procedure for the Ag(I)-coordination to selenoureas
CDCl3): δH 6.98 (s, 2H, CHimid), 2.76 (m, 12H, CH2), 2.21 (s, 6H,
CH), 1.74 (dd, J = 12.1 Hz, 12H, CH2). 13C{1H} DEPT Q NMR (101
MHz, CDCl3): δC 148.0 (C=Se), 115.6 (CHimid), 62.1 (CN), 40.2
(CH2), 36.1 (CH2), 30.3 (CH). 77Se NMR (CDCl3, 76 MHz): δSe
198.3. The data obtained matched the reported values.6
[Ag{Se(SIPr)}2][AgCl2]
A vial equipped with a stirring bar was charged with [Se(SIPr)]
(100 mg, 0.213 mmol) and AgCl (61 mg, 0.426 mmol, 2.0 equiv.)
in chloroform (2 mL). The reaction was stirred at room
temperature overnight. Afterwards, the solvent was
evaporated and the residue was filtered through Celite using
DCM which was then evaporated to yield a white powder. Yield:
General procedure for the synthesis of telluroureas via free NHCs
[Te(SIPr)]
A vial equipped with a stirring bar was charged with free SIPr 121.9 mg, 93%. 1H NMR (CDCl3, 400 MHz): δH 7.47 (t, J =7.7 Hz,
(100 mg, 0.256 mmol) and elemental tellurium (32.6 mg, 0.256 2H, Ar CH), 7.28 (d, J = 7.8 Hz, 4H, Ar CH), 4.09 (s,4H, NCH2), 2.91
mmol) in THF (10 mL) under argon. The reaction was stirred at (m, 4H, CHMe2), 1.37 (d, J = 6.8 Hz, 12H, CH3), 1.31 (d, J = 6.9 Hz,
room temperature for 16 h. The reaction was then filtered 12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 181.4
through Celite using DCM which was then evaporated to yield a (C=Se, determined by HSQC), 146.8 (Ar C), 130.7 (Ar C), 125.4
greige powder. Yield: 103 mg, 0.198 mmol, 77%. 1H NMR (CDCl3, (Ar CH), 52.0 (N(CH)2N), 29.3 (CHMe2), 24.9 (CH3), 24.7 (CH3).
400 MHz): δH 7.43 (t, J = 8 Hz, 2H, Ar CH), 7.27 (d, J = 8 Hz, 4H, CHN Calculated for C54H76Ag2Cl2N4Se2: C, 52.91; H, 6.25; N, 4.57.
Ar CH), 4.04 (s, 4H, N(CH2)2N), 3.02 (sept., J = 6.8 Hz, 4H, Found: C, 53.21; H, 6.49; N, 4.62.
CHMe2), 1.44 (d, J = 6.8 Hz, 12H, CH3), 1.31 (d, J = 7.0 Hz ,12H,
CH3). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 168.2 (C=Te), [AgCl{-Se(SIMes)}]2
147.0 (Ar C), 136.4 (Ar C), 129.7 (Ar CH), 124.7 (Ar CH), 52.6 A vial equipped with a stirring bar was charged with [Se(SIMes)]
(N(CH2)2N), 29.4 (CHMe2), 25.2 (CH3), 24.6 (CH3). CHN (100 mg, 0.259 mmol) and AgCl (74 mg, 0.519 mmol, 2.0 equiv.)
Calculated for C21H26N2Te: C, 62.58; H, 7.39; N, 5.41. Found: C, in chloroform (2.5 mL). The reaction was stirred at room
62.63; N, 5.21; H, 7.82.
temperature overnight. Afterwards, the solvent was
evaporated and the residue was filtered through Celite using
DCM which was then evaporated to yield a white powder. Yield:
[Te(SIMes)]
A vial equipped with a stirring bar was charged with free SIMes 137 mg, 94%. 1H NMR (CDCl3, 400 MHz): δH 7.02 (s, 4H, Ar CH),
(100 mg, 0.326 mmol) and elemental tellurium (41.6 mg, 0.326 4.05 (s, 4H, N(CH2)2N), 2.34 (s, 6H, CH3), 2.27 (s, 12H, CH3).
mmol) in THF (10 mL) under argon. The reaction was stirred at 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δC 177.8 (C=Se), 140.0
room temperature for 16 h. The reaction was then filtered (Ar C), 135.9 (Ar C), 133.8 (Ar C), 130.4 (Ar CH), 49.3 (N(CH2)2N),
through Celite using DCM which was then evaporated to yield a 21.4 (CH3), 17.9 (CH3). 77Se NMR (CDCl3, 76 MHz): δSe 42.0.
+
greige powder. Yield: 106 mg, 0.244 mmol, 75%. 1H NMR (CDCl3, HRMS m/z calcd for C42H52AgN4Se2 [M – (AgCl2)]+ 879.16; found
400 MHz): δH 6.99 (s, 4H, Ar CH), 4.01 (s, 4H, N(CH2)2N), 2.30 (s, 879.1569.
6H, CH3), 2.32 (s, 12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101
MHz): δH 163.0 (C=Te), 138.9 (Ar C), 136.2 (Ar C), 136.0 (Ar C), [AgCl{Se(IPrMe)}]
129.8 (Ar CH), 50.0 (N(CH2)2N), 21.3 (CH3), 18.4 (CH3). CHN A vial equipped with a stirring bar was charged with [Se(IPrMe)]
Calculated for C21H26N2Te: C, 58.11; H, 6.04; N, 6.45. Found: C, (100 mg, 0.202 mmol) and AgCl (57.8 mg, 0.404 mmol, 2.0
58.05; H, 6.44; N, 6.57.
equiv.) in chloroform (1.9 mL). The reaction was stirred at room
temperature overnight. Afterwards, the solvent was
evaporated and the residue was filtered through Celite using
DCM which was then evaporated to yield a white powder. Yield:
126 mg, 98%. 1H NMR (CDCl3, 400 MHz): δH 7.60 (t, J=7.1 Hz, 2H,
Ar CH), 7.38 (d, J = 7.7 Hz, 4H, Ar CH), 2.42 (sept., J =8 Hz, 2H,
CHMe2), 1.98 (s, 6H, CH3), 1.34 (d, J = 6.8 Hz, 12H, CHCH3), 1.20
(d, J = 6.9 Hz, 12H, CHCH3). 13C{1H} DEPT Q NMR (CDCl3, 101
MHz): δC 186.9 (C=Se), 145.9 (Ar C), 131.7 (Ar CH), 125.5 (Ar CH),
29.2 (CHMe2), 24.6 (CH3), 24.0 (CH3), 10.4 (CH3). 77Se NMR
(CDCl3, 76MHz): δSe 5.26. CHN Calculated for C29H40AgClN2Se: C,
54.52; H, 6.31; N, 4.38. Found: C, 55.17; H, 6.74; N, 4.43.
General procedure for the Cu(I)-coordination to selenoureas
[Cu{Se(SIPr)}2][CuCl2]
This complex was synthesised according to a previously
reported procedure.7
[CuCl{Se(IPrMe)}]
A vial equipped with a stirring bar was charged with [Se(IPrMe)]
(20 mg, 0.040 mmol) and CuCl (8 mg, 0.081 mmol, 2.0 equiv.) in
chloroform (1 mL). The reaction was stirred at room
temperature overnight. Afterwards, the solvent was
evaporated and the residue was filtered through Celite using
DCM which was then evaporated to yield a white powder. Yield:
General procedure for the Au(I)-coordination to selenoureas
93 %. 1H NMR (CDCl3, 400 MHz): δH 7.65 (t, J =7.8 Hz, 2H, Ar CH), [AuCl{Se(IPrMe)}]
7.41 (d, J = 7.8 Hz, 4H, Ar CH), 2.44 (sept., J = 6.6 Hz, 4H, CHMe2), A vial equipped with a stirring bar was charged with [Se(IPrMe)]
1.99 (s, 6H, CH3imid), 1.38 (d, J = 6.7 Hz, 12H, CH3), 1.22 (d, J = 6.9 (100 mg, 0.202 mmol) and [AuCl(SMe2)] (59.43 mg, 0.202 mmol,
12 | J. Name., 2012, 00, 1-3
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1 equiv.) in acetone (1 mL). The reaction was stirred at room DJN thanks the University of Strathclyde for aViCewhAarnticclee lOlonlrin'es
temperature for 3 h. Afterwards, the solvent was evaporated Fellowship (2014-18) and Mr Craig Irving DaOndI: 1D0r.1J0o3h9/nDP0DarTk0i2n5s5o8nE
and the residue was filtered through Celite using DCM which for assistance with NMR spectroscopy facilities. S.P.N. thanks
was then evaporated to yield a white powder. Yield: 148.8 mg, the Special Research Fund (BOF) of Ghent University (Doctoral
99%. 1H NMR (CDCl3, 400 MHz): δH 7.64 (t, J =7.8 Hz, 2H, Ar CH), Scholarship 01D14919, as well as starter and senior research
7.39 (d, J = 7.8 Hz, 4H, Ar CH), 2.41 (sept., J = 6.8 Hz, 2H), 2.00 grants) for support. Umicore AG is thanked for gifts of materials.
(s, 6H, CH3), 1.40 (d, J = 6.8 Hz, 12H, CH3), 1.21 (d, J = 6.9 Hz, KVH, FN and MS thank the Hercules Foundation (project
12H, CH3). 13C{1H} DEPT Q NMR (CDCl3, 101 MHz): δc 147.5 AUGE/11/029) and the Special Research Fund (BOF) – UGent
(C=Se), 145.8 (Ar C), 131.8 (Ar CH), 131.0 (Ar C), 127.5 (Ar C), (project 01N03217) for funding.
125.5 (Ar CH), 29.3 (CHMe2), 24.5 (CH3), 24.1 (CH3), 10.3 (CH3).
77Se NMR (CDCl3, 76MHz): δSe 88.9. CHN Calculated for
C29H40AuClN2Se: C, 47.84; H, 5.54; N, 3.85. Found: C, 47.39; H,
Notes and references
5.57; N, 3.92.
§ Crystallographic data underpinning this study can be
downloaded from the Cambridge Structural Database (CSD) via
the following link: https://www.ccdc.cam.ac.uk/structures/
(CCDC 1997588-1997598). See supporting information for more
details.
[AuCl{Se(IPrCl)}]
This complex was synthesised according to a previously
reported procedure.8
1
M. N. Hopkinson, C. Richter, M. Schedler and F. Glorius, Nature,
2014, 510, 485-496.
[AuCl{Se(ICy)}]
A vial equipped with a stirring bar was charged with [Se(ICy)]
(100 mg, 0.321 mmol) and [AuCl(SMe2)] (94.6 mg, 0.321 mmol,
1 equiv.) in acetone (1.4 mL). The reaction was stirred at room
temperature for 3 h. Afterwards, the solvent was evaporated
and the residue was filtered through Celite using DCM which
was then evaporated to yield a white powder. Yield: 177 mg,
2
3
H. Clavier and S. P. Nolan, Chem. Commun., 2010, 46, 841-861
D. J. Nelson and S. P. Nolan, Chem. Soc. Rev., 2013, 42, 6723-
6753.
H. V. Huynh, Chem. Rev., 2018, 118, 9457-9492.
D. J. Nelson, A. Collado, S. Manzini, S. Meiries, A. M. Z. Slawin,
D. B. Cordes and S. P. Nolan, Organometallics, 2014, 33, 2048-
2058.
S. V. C. Vummaleti, D. J. Nelson, A. Poater, A. Gomez-Suarez, D.
B. Cordes, A. M. Z. Slawin, S. P. Nolan and L. Cavallo, Chem. Sci.,
2015, 6, 1895-1904.
F. Nahra, K. Van Hecke, A. R. Kennedy and D. J. Nelson, Dalton
Trans., 2018, 47, 10671-10684.
4
5
1
99%. H NMR (CDCl3, 400 MHz): δH 7.13 (s, 2H, N(CH)2N), 4.98
(ddd, J=15.4, 7.8, 3.8 Hz, 2H, N-CH), 2.21-2.16 (m, 4H, CH2), 1.94-
1.87 (m, 4H, CH2), 1.81-1.77 (m, 2H, CH2), 1.56 – 1.47 (m, 8H,
CH2), 1.27-1.17 (m, 2H, CH2). 13C{1H} DEPT Q NMR (CDCl3, 101
MHz): δC 139.1 (C=Se), 118.6 (CHimid), 59.8 (NCH), 31.2 (CH2),
25.4 (CH2), 25.1 (CH2). 77Se NMR (CDCl3, 76 MHz): δSe -60.4. CHN
Calculated for C15H24AuClN2Se: C, 33.13; H, 4.45; N, 5.15. Found:
C, 33.42; H, 4.65; N, 5.46.
6
7
8
9
D. J. Nelson, F. Nahra, S. R. Patrick, D. B. Cordes, A. M. Z. Slawin
and S. P. Nolan, Organometallics, 2014, 33, 3640-3645.
A. Liske, K. Verlinden, H. Buhl, K. Schaper and C. Ganter,
Organometallics, 2013, 32, 5269-5272.
[Au{Se(IAd)}2][AuCl2]
A vial equipped with a stirring bar was charged with [Se(IAd)]
(100 mg, 0.241 mmol) and [AuCl(SMe2)] (70. 9 mg, 0.241 mmol,
1 equiv.) in acetone (1.1 mL). The reaction was stirred at room
temperature for 3 h. Afterwards, the solvent was evaporated
and the residue was filtered through Celite using DCM which
was then evaporated to yield a brown powder. Yield: 144.9 mg,
93%. 1H NMR (400 MHz; CDCl3): δH 7.24 (s, J= 5.9 Hz, 2H, CHimid),
2.76 (d, J = 2.5 Hz, 12H, CH2), 2.30 (br. s, 6H, CH), 1.76 (m, 6H,
CH2), 1.75 (m, 6H, CH2). 13C{1H} DEPT Q NMR (101 MHz, CDCl3):
δC 132.6 (C=Se), 118.6 (CHimid), 65.5 (CN), 41.4 (CH2), 35.7 (CH2),
30.3 (CH). 77Se NMR (CDCl3, 76 MHz): δSe 110.7. HRMS m/z calcd
10 K. Verlinden, H. Buhl, W. Frank and C. Ganter, Eur. J. Inorg.
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7112.
+
for C46H64AuN4Se2 [M – (AuCl2)]+ 1029.31; found 1029.3170.
16 J. E. McDonough, A. Mendiratta, J. J. Curley, G. C. Fortman, S.
Fantasia, C. C. Cummins, E. V. Rybak-Akimova, S. P. Nolan and C.
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Conflicts of interest
There are no conflicts to declare.
18 K. Srinivas, P. Suresh, C. N. Babu, A. Sathyanarayana and G.
Prabusankar, RSC Adv., 2015, 5, 15579-15590.
Acknowledgements
This journal is © The Royal Society of Chemistry 20xx
J. Name., 2013, 00, 1-3 | 13
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ARTICLE
Journal Name
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TOC: Herein, we describe a straightforward access to chalcogenoureas derived from N-hDeOteI:r1o0.c10y3c9l/icD0DT02558E
carbenes, and we investigate the coordination chemistry of selenoureas with coinage metals.