Synthesis and characterization of N,N-Di-substituted acylthiourea copper(II) complexes

Article abstract of DOI:10.1002/zaac.201400605

A series of six N,N-di-substituted acylthiourea ArC(O)NHC(S)NRR ligands (denoted as HLⁿ) [Ar = 1-Naph: NRR = NPh₂, HL¹ (1); N(iPr)Ph, HL² (2). Ar = Mes: NRR = NPh₂, HL⁴ (3); N(iPr)Ph, HL

Full text of DOI:10.1002/zaac.201400605

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DOI: 10.1002/zaac.201400605
Synthesis and Characterization of N,N-Di-substituted Acylthiourea
Copper(II) Complexes
Su-Yun Wu,[a] Xiao-Ya Zhao,[a] Hai-Pu Li,[a] Ying Yang,*[a] and Herbert W. Roesky*[b]
Dedicated to Veronique Gouverneur on the Occasion of Receiving the ACS Fluorine Award
Keywords: Acylthiourea; Copper; S ligands; Configuration; X-ray diffraction
Abstract.
A
series of six N,N-di-substituted acylthiourea
is bound to the CuII atom in a bidentate-(O,S) coordination mode.
ArC(O)NHC(S)NRRЈ ligands (denoted as HLn) [Ar = 1-Naph: NRRЈ Similarly treatment of HL2 (2) with NaOAc and CuCl resulted in the
= NPh2, HL1 (1); N(iPr)Ph, HL2 (2). Ar = Mes: NRRЈ = NPh2, HL4 formation of the cis-arranged product [cis-CuL2 (8)]. The reaction of
2
(3); N(iPr)Ph, HL5 (4); NEt2, HL6 (5). Ar = Ph: NRRЈ = N(iPr)Ph, mesityl derivative HL4 (3) and CuBr with and without the addition of
HL8 (6)] were synthesized and characterized. These ligands were de- NaOAc gave the cis-CuL4 (9) and cis-(HL4)2CuBr (10), respectively.
2
protonated to form CuII complexes through metathesis or combined In contrast, reaction of HL5 (4) and CuI in the presence of NaOAc
redox reaction with copper halides. The structures of the complexes resulted in trans-CuL5 (11). Alternatively trans-CuL6 (12) was ob-
2
2
were investigated with single-crystal X-ray diffraction. The reaction of tained by the reaction of diethyl-substituted HL6 (5) with CuCl2 in the
the 1-naphthalene derivative HL1 (1) with CuBr in the presence of absence of a base.
sodium acetate produced cis-CuL12 (7), where the deprotonated ligand
The bis-chelating coordination mode adopted by N,N-di-
substituted acylthiourea ligands always leads to square planar
Introduction
Acylthiourea with the core structure C(O)NHC(S)N con-
metal complexes, predominantly with cis geometrical configu-
tains both hard and soft donor sites. These characteristics favor
ration. For instance, the complexes with CoII,[4] NiII,[5] PdII,[6]
metal ion complexations and thus have found extensive appli-
cations.[1] The ligand properties also depend greatly on the
and PtII[7] are mostly cis products. The CuII analogues have a
similar configuration.[8] CuII complexes with trans arrange-
number and nature of the substituents at the terminal nitrogen
ment are rarely known. They are unintentionally obtained dur-
atoms as well as on the acyl groups.[2] The N-alkyl/aryl-NЈ-
ing the preparation of cis/trans isomers supported by N,N-di-
acylthiourea (H2L) is prepared from ArNCS and a primary
ethyl-NЈ-(p-nitrobenzoyl) thiourea.[9] Moreover, the related
amine H2NR. This ligand reduces the CuII halide in solution
complexes trans-bis(N-pyrrolidine-NЈ-(2-chlorobenzoyl) thio-
to give the CuI adduct and functions as a S donor.[3] However,
urea) copper(II)[10] and bis(N-piperidine-NЈ-(2-fluorobenzoyl)
H2L was not common to be deprotonated to give the anionic
thiourea) copper(II) were also reported.[11]
ligand. In contrast, the N,N-di-substituted acylthiourea (HL),
which can be prepared from ArNCS and HNRRЈ, is able to
The first example of a bis acylthiourea PtII complex with a
trans arrangement can be mainly attributed to the introduction
function as a S donor or as a monoanionic ligand by oxidizing
of a sterically demanding naphthyl substituent.[12] This prac-
the CuI halide to afford a bis-chelate CuII complex.
tice likely transmitted an informative message to acquire the
trans-arranged CuII product by designing the acylthiourea li-
gands. In this regard, we used new naphthyl derivatives and
related ligands with the intension to isolate trans bis-chelate
CuII complexes. Herein, six different N,N-di-substituted acyl-
thiourea ArC(O)NHC(S)NRRЈ ligands are described with vari-
ous Ar and NRRЈ groups. Their reactions with copper halides
resulted in CuII complexes, which are reported including their
spectroscopic and structural characterization.
* Dr. Y. Yang
Fax: +86-731-88879616
E-Mail: yangy@csu.edu.cn
* Prof. Dr. H. W. Roesky
Fax: +49-551-39-33373
E-Mail: hroesky@gwdg.de
[a] School of Chemistry and Chemical Engineering
Centre for Environment and Water Resource
Central South University
Lushannan Road 932
410083 Changsha, P. R. China
[b] Institut für Anorganische Chemie
Universität Göttingen
Results and Discussion
Tammannstrasse 4
37077 Göttingen, Germany
Six
N,N-di-substituted
acylthiourea
ligands
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201400605 or from the au-
thor.
ArC(O)NHC(S)NRRЈ [Ar = 1-Naph: NRRЈ = NPh2, HL1 (1);
N(iPr)Ph, HL2 (2). Ar = Mes: NRRЈ = NPh2, HL4 (3);
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N(iPr)Ph, HL5 (4); NEt2, HL6 (5). Ar = Ph: NRRЈ = N(iPr)Ph,
HL8 (6)] were prepared according to reported methods. Four
related known acylthioureas are also listed in Scheme 1 (Ar =
1-Naph: NRRЈ = NEt2, HL3.[8a] Ar = Ph: NRRЈ = NPh2, HL7;[9]
NEt2, HL9.[8b] Ar = p-NO2-C6H4, NRRЈ = NEt2, HL10[9]). The
common procedure for the synthesis of ligands HLn involves
the reaction of substituted benzoyl chloride ArC(O)Cl with po-
tassium thiocyanate KSCN in acetone, followed by the con-
densation of the in-situ formed benzoyl-isothiocyanate ArNCS
with the selected secondary amine HNRRЈ (NRRЈ = NPh2,
N(iPr)Ph, NEt2).[13] The HLn products (1–6) were purified by
Figure 1. Molecular structure of HL1 (1). Except NH other hydrogen
1
recrystallization and characterized by H and 13C NMR, FT-
atoms are omitted for clarity. Selected bond lengths /Å and angles /°:
N(1)–C(2) 1.388(2), N(1)–C(1) 1.389(2), N(2)–C(1) 1.343(2), O(1)–
C(2) 1.210(2), S(1)–C(1) 1.6705(17); C(1)–N(1)–C(2) 126.81(14),
N(1)–C(1)–N(2) 117.91(14).
IR spectroscopy and elemental analysis. The analytical and
spectroscopic data are consistent with the proposed structures
shown in Scheme 1.
It is well known that acylthiourea derivatives are showing
hydrogen bonds between N donors and O/S acceptors. In the
case of HL1 (1) two neighboring molecules are arranged by a
pair of N–H···S hydrogen bonds. Moreover, there are weak
intermolecular π–π stacking interactions between naphthalene
rings to form a double chain along the a axis (Figure S1, Sup-
porting Information).
The overall structure of HL5 (4) is nearly analogous to that
of HL1 (1) in view of the arrangement of the ligand skeleton
and the substituents. HL5 crystallizes in the monoclinic space
group Pc with two symmetry independent molecules in a cen-
trosymmetric unit (Figure S2, Supporting Information). The
O(1)–C(2) [1.222(3) Å] and S(1)–C(1) [1.646(3) Å] bond
lengths are comparable to those of HL1 (1). The intermolecular
arrangement is shown in Figure S3 (see Supporting Infor-
mation).
Scheme 1. Preparation of N,N-di-substituted acylthiourea ligands HLn
(1–6).
The assignments of the 1H and 13C NMR spectra of HLn are
straightforward with the expected set of ligand protons and
carbon resonances, and are further confirmed by 1H-13C HSQC
NMR experiments. In the low-field of each 1H NMR spectrum
of HLn, the characteristic singlet is assignable to the proton
resonance for the NH group. The chemical shifts of the HN
functionality recorded in CDCl3 are given in Table 1. The NH
absorption bands in the range of 3100–3300 cm–1 in the FT-IR
spectra are also listed in Table 1.
The reaction of HL1 (1) with CuBr in the presence of so-
dium acetate in dichloromethane afforded a dark green solid
by eliminating acetic acid and sodium bromide and releasing
hydrogen gas (7) (Scheme 2), which is in sharp contrast to
those from colorless to light yellow CuI adducts of acylthio-
urea with CuX (X = Cl, Br, I). The distinct color is indicative
1
for the formation of the CuII complex.[8,14] In addition, the H
The solid structures of N,N-diphenyl-NЈ-(1-naphthoyl) thio-
urea (HL1, 1) and N-isopropyl-N-phenyl-NЈ-(2,4,6-trimeth-
ylbenzoyl)thiourea (HL5, 4) were further determined by single-
crystal X-ray diffraction. HL1 (1) crystallizes in the orthorhom-
bic space group Pbca, as depicted in Figure 1 with selected
bond lengths and angles. Crystal data and structure refinements
are listed in Table S1 (see Supporting Information). The O(1)–
C(2) [1.210(2) Å] and S(1)–C(1) [1.6705(17) Å] bond lengths
are found in the range of typical double bonds.[8]
Scheme 2. Preparation of complexes 7 and 8.
Table 1. Proton chemical shifts in CDCl3 and FT-IR stretching frequency of the NH functionality of HLn.
NH functionality
HL1
HL2
HL4
HL5
HL6
HL8
1H NMR /ppm
FT-IR /cm–1
8.71
3156
8.07
3176
8.06
3268
7.54
3138
7.80
3192
8.09
3194
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NMR spectrum of 7 displays very broad signals due to its
Compared with literature data it is shown that both diphenyl
derivatives, HL1 (1) and HL7, gave the cis bis-chelate CuII
complexes. It is of interest to know whether a phenyl-iPr sub-
stituent at the terminal nitrogen atom of the acylthiourea ligand
changes the properties in such a way that the formation of
trans product is favored. Following this idea, the reaction of
N-isopropyl-N-phenyl-NЈ-(1-naphthoyl)thiourea (HL2, 2) and
CuCl in the presence of NaOAc was performed to isolate a
dark green solid (8) (Scheme 2). The single-crystal X-ray
analysis revealed that complex 8 crystallizes in the monoclinic
paramagnetic nature. In the FT-IR spectrum the absorption
band for NH stretching vibration, observed at 3156 cm–1 in the
uncomplexed ligand HL1, has disappeared due to the deproton-
ation of HL1. At the same time, the C=O (1627 cm–1) and C=S
(1109 cm–1) stretching frequencies of 7 were found to be red
shifted upon complexation, relative to those for the free ligand
HL1 (1697 and 1156 cm–1), thus suggesting a bi-chelating be-
havior of ligand to central metal atom through O and S
atoms.[8,15] The elemental analysis of 7 shows a composition
in a 2:1 stoichiometric ratio of the anionic ligand to copper.
Single crystals of 7 suitable for X-ray structural analysis
were grown from a saturated THF solution. 7·THF crystallizes
space group I2/a as a cis arranged complex (cis-CuL2 , Figure
2
S5, Supporting Information). The sum of bond angles at the
central copper atom (365.19°) and the dihedral angle between
OCuS planes (23.56°) was found to be larger than that in cis-
¯
in the triclinic space group P1, and the molecular structure is
CuL1 (7).
shown (Figure 2) with relevant bond lengths and angles in the
2
Previously N,N-diethyl-NЈ-(1-naphthoyl)thiourea (HL3) has
caption of Figure 2. The overall structure of 7 can be described
as a cis-CuL1 and it is analogous to those of the diphenyl
been used to form a CuII complex (cis-CuL3 ).[8a] Inspection
2
2
derivative cis-CuL72 and other related complexes with cis con-
figuration.[8,9] Compared with the structure of the free ligand
HL1 (1), the bond lengths of the carbonyl [O(1)–C(2) 1.262(3),
O(2)–C(26) 1.253(3) Å] and thiocarbonyl [S(1)–C(1) 1.728(3),
of the molecular structure of cis-CuL3 revealed that the angle
2
at the copper atom (359.82°) and the dihedral angle (11.05°)
are appreciably smaller than those of cis-CuL1 (7) and cis-
2
CuL22 (8). A comparison of the three dihedral angles of 23.56°
S(2)–C(25) 1.719(3) Å] moieties in the complex cis-CuL1 (7)
(cis-CuL2 , 8), 19.38° (cis-CuL1 , 7), and 11.05° (cis-CuL3 )
2
2
2
2
are longer than those in the ligand [O(1)–C(2) 1.210(2), S(1)–
C(1) 1.6705(17) Å], while the N–C bond lengths in this com-
plex are evidently shorter. This observation essentially reflects
the electron delocalization over the chelate ring.[8c] During the
complexation, the C(S)NPh2 moiety has rotated half a turn
along the N(1)–C(1) bond to complete the chelate ring. The
arrangement around the Cu atom is a slightly distorted square
with the sum of bond angles at the copper atom of 362.47°.
Correspondingly, the dihedral angle between two OCuS planes
is 19.38°, due to the repulsive interaction among the bulky 1-
Naph substituents. From the packing diagram of 7, it is found
that there is significant intermolecular π–π interaction between
the naphthalene rings of two discrete molecules in the crystal
(Figure S4, Supporting Information).
of the cis bis-chelate naphthalene CuII complexes shows a
plausible sequence of the three NRR’ substituents
N(iPr)Ph Ͼ NPh2 Ͼ NEt2. In this order the distortion of the
square environment is enhanced.
All three naphthalene derivatives (HL1–3) correspond to the
cis bis-chelate CuII complexes, although the naphthyl ring
should have a stronger influence due to its bigger size when
compared with those of the investigated NRRЈ groups
[N(iPr)Ph, NPh2, NEt2]. The fine tuning of the NRRЈ substitu-
ents did not change the results in the scope of the current in-
vestigation.
It is well known that the cis product is thermodynamically
favored, as found in a number of examples.[4–8] The cis/trans
isomers of CuII complex with HL10 (Scheme 1) provide a good
example to compare the structural difference between cis and
trans products.[9] In the cis-CuL102, the angle at the central
copper atom (360.05°) is considerably close to the ideal angle
of 360°, while the dihedral angle (2.51°) is very small. This
observation is close to those in trans-CuL102 (exactly 360° and
0°, respectively). The right combination of Ar and NRRЈ
groups may help to reduce the distortion of the coordination
square in the cis configuration and promotes the formation of
the trans product.
When the steric hindrance of the Ar group of the N,N-di-
substituted acylthiourea is decreased from naphthyl to phenyl
ring, all four diethyl and diphenyl acylthioureas are known
to form the cis bis-chelate CuII products [cis-CuL1 (7), cis-
2
CuL3 ,[8a] cis-CuL7 ,[9] and cis-CuL9 [8b]]. It can therefore be
2
2
2
Figure 2. Molecular structure of cis-CuLl2 (7). Hydrogen atoms and
solvent molecule are omitted for clarity. Selected bond lengths /Å and
angles /°: Cu(1)–O(1) 1.9334(18), Cu(1)–O(2) 1.9388(18), Cu(1)–S(1)
2.2267(8), Cu(1)–S(2) 2.2273(8), N(1)–C(1) 1.331(3), N(1)–C(2)
1.333(3), N(3)–C(26) 1.325(3), N(3)–C(25) 1.332(3), O(1)–C(2)
1.262(3), O(2)–C(26) 1.253(3), S(1)–C(1) 1.728(3), S(2)–C(25)
1.719(3); O(1)–Cu(1)–S(1) 94.43(6), O(2)–Cu(1)–S(2) 93.63(6).
postulated that an intermediate size Ar group may trigger a
change between a naphthyl group and an unsubstituted phenyl
ring. An in-between adjustment of the size of the substituents
at the phenyl group might be a compromise (see Ref. [7a]).
Based on this assumption the Mes group was chosen as the
new ligand for further investigations.
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The reaction of N,N-diphenyl-NЈ-(2,4,6-trimethylbenzoyl) acetone without the addition of any base, and this reaction was
thiourea (HL4, 3) with CuBr was carried in dichloromethane found to proceed smoothly to give a blue-green solid (12)
in the presence of sodium acetate to afford a light green solid (Scheme 3). It is suggested that the molecular elimination of
(9) (Scheme 3). Complex 9 was established by X-ray structural HCl between HL6 and CuCl2 is highly spontaneous to result
analysis. 9 crystallizes in the monoclinic space group P21/c in complex formation. Parallel experiments using HL6 with
and was determined as a cis product, cis-CuL4 (Figure S6, CuX (X = Br, I) revealed that the presence of NaOAc is still
2
Supporting Information). The dihedral angle between two necessary to afford the same CuII product.
OCuS planes was additional useful information. When com-
Complex 12 crystallizes in the monoclinic space group
P21/n. The X-ray crystal dada of 12 confirm that the CuII atom
is chelated by two anionic ligands L6 in trans conformation
pared to the respective data of CuII analogues cis-CuL1
2
(19.38°) and cis-CuL7 (12.36°), it was noticed that cis-CuL4
2
2
(9) gave an intermediate value of 16.77°, indicating that the (Figure 3).
Mes group plays an expected and reasonable role in mediating
the OCuS dihedral angle.
Scheme 3. Preparation of complexes 9–12.
It has been known that in the CuI adducts (H2L)2CuX or
(HL)2CuX (X = Cl, Br, I), the acylthiourea ligands always are
arranged in cis position, driven by the orientation of intramo-
lecular N–H···X hydrogen bond interaction.[3] For example, the
same reaction of HL4 with CuBr in the absence of NaOAc
gave a bright yellow solid, which turned out to be the 2:1
adduct cis-(HL4)2CuBr (10) (Scheme 3), as revealed by the X-
ray diffraction study (Figure S7, Supporting Information).
Actually, during the formation of the CuII complex sup-
ported by deprotonated acylthiourea ligand, the trans product
Figure 3. Molecular structure of trans-CuL6 (12). Hydrogen atoms
are omitted for clarity. Thermal ellipsoids are drawn at 30% level.
Selected bond lengths /Å and angles /°: Cu(1)–O(1) 1.925(2), Cu(1)–
S(1) 2.2529(9), N(1)–C(2) 1.311(4), N(1)–C(1) 1.351(4), O(1)–C(2)
2
might be formed, as long as the Ar and NRRЈ couple match to 1.264(3), S(1)–C(1) 1.729(3); O(1)–Cu(1)–S(1) 93.79(7).
each other. The structural results of cis-CuL4 (9) initiated the
idea of products with N(iPr)Ph and NEt2 substituents to com-
pare these results with that of the known NPh2 derivative.
2
The Cu–S [2.2529(9) Å] and Cu–O [1.925(2) Å] bond
lengths in trans-CuL6 (12) are comparable to or slightly
2
longer than those of trans-CuL9 [2.253(1) and 1.901(2) Å],[9]
2
The reaction of N-isopropyl-N-phenyl-NЈ-(2,4,6-trimeth-
as well as trans-bis(N-pyrrolidine-NЈ-(2-chlorobenzoyl) thio-
ylbenzoyl)thiourea (HL5, 4) and CuI in the presence of
urea)copper(II)[10] [2.2417(6) and 1.9078(15) Å] and trans-
NaOAc, gave a yellow-green solid (11) (Scheme 3). The color
bis(N-piperidine-NЈ-(2-fluorobenzoyl)thiourea)
copper(II)
suggested the formation of the CuII complex, which was fur-
ther confirmed by analytical and spectroscopic data.
Recrystallization, however, gave piles of pale green hexagonal
flakes. The quality of single crystals of 11 did not allow to
obtain the molecular geometric parameters with sufficient ac-
curacy, but they were adequate to characterize complex 11 as
[2.249 and 1.896 Å].[11] It is noticeable that, for each of the
four cases in trans configuration, the CuII atom lies in a crys-
tallographic inversion center and the dihedral angle of OCuS
planes was exactly 0° to present a strictly square-planar ar-
rangement.
The products of N-isopropyl-N-phenyl-NЈ-(benzoyl) thio-
urea (HL8, 6) with copper halides in a variety of solvents failed
to yield X-ray quality crystals.
trans-CuL5 (Figure S8, Supporting Information).[16]
2
Encouraged by this result, we further tried the preparation
of N,N-diethyl-NЈ-(2,4,6-trimethylbenzoyl)thiourea (HL6, 5),
where the former NPh2 moiety in HL4 is replaced by NEt2. In
the literature the N,N-diethyl acylthiourea complexes with an
extensive range of Ar groups have been known to form cis bis-
chelate CuII complexes (Table S2, Supporting Information).
One known exception was the CuII complex supported by sized and deprotonated to support the bis-chelate CuII com-
HL10 (Scheme 1), with both cis and trans isomers.[9] In the plexes. Single crystal X-ray structural analysis revealed that
current work, HL6 (5) was tentatively treated with CuCl2 in when Ar is the steric demanding 1-naphthalene ring, the result-
Conclusions
Six N,N-di-substituted acylthiourea ligands were synthe-
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806 (m), 778 (s), 758 (s), 693 (s), 630 (s), 583 (m) cm–1. C24H18N2OS
(382.5): calcd. C, 75.37; H, 4.74; N, 7.32; S, 8.38%; found C, 75.33;
H, 4.77; N, 7.23; S, 8.35%. Colorless X-ray quality single crystals of
1 were obtained from a concentrated THF solution.
ant CuII complexes are always in cis arrangement [like cis-
CuL1 (7), cis-CuL2 (8), and cis-CuL3 [8a]] regardless of the
2
2
2
tuning of the NRRЈ substituents. The phenyl ring (Ar) exhibits
a similar situation to give cis-CuL7 [9] and cis-CuL9 .[8b] Ex-
2
2
N-Isopropyl-N-phenyl-NЈ-(1-naphthoyl)thiourea (HL2) (2): White
have to match each other and one of the two should not be solid. Yield 80%. M.p. 155–156 °C. 1H NMR (500 MHz, CDCl3):
amination of the structural data suggested that Ar and NRRЈ
δ = 8.07 (s, 1 H, NH), 7.90 (d, 1 H, Naph-H), 7.84 (d, 1 H, Naph-H),
7.79 (d, 1 H, Naph-H), 7.44 (m, 5 H, Ph-H), 7.40 (d, 1 H, Naph-H),
7.29 (m, 3 H, Naph-H), 7.15 (d, 1 H, Naph-H), 5.77 (sept, 1 H,
CH(CH3)2), 1.24 (d, 6 H, CH(CH3)2) ppm. 13C NMR (101 MHz,
CDCl3): δ = 179.64 (C=S), 165.25 (C=O), 133.57, 131.73, 129.99,
129.05, 128.88, 128.29, 127.42, 126.58, 125.49, 125.07, 124.40 (Naph/
Ph-C), 54.28 (CH(CH3)2), 20.50 (CH(CH3)2) ppm. FT-IR (KBr): ν˜ =
3176 (w, NH), 2980 (w), 1696 (s, C=O), 1504 (s), 1400 (s), 1348 (m),
1248 (m), 1233 (s), 1184 (m), 1152 (s), 1134 (s, C=S), 1104 (s), 908
(w), 854 (w), 813 (m), 781 (s), 734 (m), 710 (m), 624 (m), 595 (m),
exceedingly more bulky than the other one in order to obtain
the trans product. By following this assumption, the Mes
group was introduced to comprise the size between naphthal-
ene and substituted phenyl rings. Starting from cis-CuL4 (9)
2
two trans bis-chelate CuII complexes were obtained, trans-
CuL5 (11) and trans-CuL6 (12), by enlarging or diminishing
2
2
the NRRЈ groups of the N,N-di-substituted acylthioureas. They
represent the first examples of such a trans system by design
with acyclic NRRЈ substituents and without being accompanied
by their cis isomers. These results show the importance of 522 (m) cm–1. C21H20N2OS (348.5): calcd. C, 72.38; H, 5.79; N, 8.04;
S, 9.20%; found C, 72.15; H, 5.70; N, 7.88; S, 9.33%.
balancing the Ar and NRRЈ flanks in size to obtain a matchable
couple, where the dihedral angle of the OCuS planes can
shrink. This allows that the geometric difference of the core
structure between a cis and a trans isomer can be minimized
to reach a transition state. Under such a condition, also the
N,N-Diphenyl-NЈ-(2,4,6-trimethylbenzoyl)thiourea
(HL4) (3):
Bright yellow solid. Yield 53%. M.p. 199–200 °C. 1H NMR
(500 MHz, CDCl3): δ = 8.06 (s, 1 H, NH), 7.38 (m, 8 H, Ph-H),
7.28(m, 2 H, Ph-H), 6.75 (s, 2 H, Mes-H), 2.23 (s, 3 H, p-Me-Mes),
formation of a trans product is even more favorable during 1.98 (s, 6 H, o-Me-Mes) ppm. 13C NMR (101 MHz, CDCl3): δ =
181.90 (C=S), 165.26 (C=O), 145.82, 139.36, 134.37, 133.01, 129.33,
128.38, 127.62, 127.29 (Ar-C), 21.09, 18.91 (Ar-CH3) ppm. FT-IR
(KBr): ν˜ = 3268 (w, NH), 1669 (s, C=O), 1610 (w), 1490 (vs), 1453
(m), 1374 (s), 1263 (s), 1199 (s, C=S), 1152 (m), 1085 (w), 848 (w),
758 (m), 691 (m), 633 (w), 600 (m) cm–1. C23H22N2OS (374.5): calcd.
C, 73.76; H, 5.92; N, 7.48; S, 8.56%; found C, 73.85; H, 5.88; N,
7.36; S, 8.67%.
complexation. Nevertheless, this should be carefully applied
because there are additional factors, like intermolecular inter-
action, accounting for the variation of molecules.[9] It is im-
plied that, although the trans product was solely observed in
our work and those of reported examples,[10,11] it is still pos-
sible that the cis isomer could exist due to its thermodynamic
favored formation.
N-Isopropyl-N-phenyl-NЈ-(2,4,6-trimethylbenzoyl)thiourea (HL5)
1
(4): White solid. Yield 91%. M.p. 197–198 °C. H NMR (500 MHz,
CDCl3): δ = 7.54 (s, 1 H, NH), 7.43 (m, 3 H, Ph-H), 7.23 (m, 2 H,
Ph-H), 6.71 (s, 2 H, Mes-H), 5.69 (sept, 1 H, CH(CH3)2), 2.21 (s, 3
H, p-Me-Mes), 1.90 (s, 6 H, o-Me-Mes), 1.19 (d, 6 H, CH(CH3)2)
ppm. 13C NMR (101 MHz, CDCl3): δ = 179.30 (C=S), 167.05 (C=O),
138.97, 138.76, 134.18, 133.44 (Mes-C), 129.12, 129.00, 128.90 (Ph-
C), 128.17 (Mes-C), 54.45 (CH(CH3)2), 21.07 (p-Me-Mes), 20.42
(CH(CH3)2), 18.73 (o-Me-Mes) ppm. FT-IR (KBr): ν˜ = 3138 (m, NH),
2972 (s), 1659 (vs, C=O), 1611 (m), 1501 (vs), 1404 (vs), 1348 (s),
1283 (m), 1244 (vs), 1167 (s, C=S), 1116 (m), 1088 (s), 909 (m), 844
(m), 758 (m), 702 (s), 683 (m), 592 (m) cm–1. C20H24N2OS (340.5):
calcd. C, 70.55; H, 7.10; N, 8.23; S, 9.42%; found C, 70.43; H, 7.01;
N, 8.17; S, 9.57%. Colorless X-ray quality single crystals of 4 were
obtained from a concentrated THF solution.
Experimental Section
All chemicals commercially available used in the synthesis were of
analytical grade and used as received. Melting points were measured in
a sealed glass tubes with a Büchi B-540 instrument without correction.
Elemental analyses for carbon, hydrogen, and nitrogen were performed
with a Thermo Quest Italia SPA EA1110 instrument. The H and 13C
1
NMR spectra were recorded with 5 mm tubes in CDCl3 solution using
AVANCE III 400 and AVANCE III HD 500 spectrometers. Infrared
spectra were recorded by using KBr pellets with a NEXUS670
(Thermo Fisher Scientific) FT-IR spectrometer.
The ligands were prepared according to the method of Douglass and
Dains.[13] The syntheses of N,N-diethyl-NЈ-(1-naphthoyl)thiourea HL3,
N,N-diphenyl-NЈ-(benzoyl)thiourea HL7, N,N-diethyl-NЈ-(benzoyl)-
thiourea HL9, N,N-diethyl-NЈ-(p-nitrobenzoyl) thiourea HL10, and their
CuII complexes have been reported elsewhere. The analytical and FT-
IR data for the new ligands and their respective complexes are given
below.
N,N-Diethyl-NЈ-(2,4,6-trimethylbenzoyl)thiourea (HL6) (5): White
solid. Yield 20%. M.p. 113–114 °C. 1H NMR (500 MHz, CDCl3):
δ = 7.80 (s, 1 H, NH), 6.85 (s, 2 H, Mes-H), 4.00 (s, 2 H, CH2CH3),
3.77 (s, 2 H, CH2CH3), 2.33 (s, 6 H, o–Me–Mes), 2.28 (s, 3H p–Me–
Mes), 1.35 (t, 6 H, CH2CH3) ppm. 13C NMR (126 MHz, CDCl3): δ =
178.51 (C=S), 167.14 (C=O), 139.43, 134.31, 133.46, 128.48 (Mes-C),
48.26, 47.95 (CH2CH3), 21.13 (p-Me-Mes), 19.24 (o-Me-Mes), 13.40,
11.54 (CH2CH3) ppm. FT-IR (KBr): ν˜ = 3192 (w, NH), 2974 (w),
1696 (s, C=O), 1542 (s), 1444 (s), 1425 (s), 1374 (m), 1354 (w),1286
(m), 1257 (m), 1227 (s), 1174 (m), 1131 (m, C=S), 1074 (m), 1056
(w), 852 (m), 687 (w) cm–1. C15H22N2OS (278.4): calcd. C, 64.71; H,
7.96; N, 10.06; S, 11.52%; found C, 64.66; H, 7.85; N, 10.00; S,
11.67%.
N,N-Diphenyl-NЈ-(1-naphthoyl)thiourea (HL1) (1): Pale yellow so-
lid. Yield 80%. M.p. 151–152 °C. H NMR (500 MHz, CDCl3): δ =
1
8.71 (s, 1 H, NH), 7.98 (d, 1 H, Naph-H), 7.93(d, 1 H, Naph-H), 7.84
(d, 1 H, Naph-H), 7.51 (m, 3 H, Naph-H), 7.42 (m, 10 H, Ph-H), 7.30
(m, 2 H, Naph-H) ppm. 13C NMR (101 MHz, CDCl3): δ = 182.26
(C=S), 163.41 (C=O), 132.21 (Naph-C), 129.31 (Ph-C), 128.34 (Naph-
C), 127.62 (Naph-C), 127.52 (Naph-C), 126.99 (Ph-C), 126.71 (Naph-
C), 125.86 (Naph-C), 125.05 (Naph-C), 124.37 (Ph-C) ppm. FT-IR
(KBr): ν˜ = 3156 (w, NH), 1697 (s, C=O), 1592 (w), 1492 (s), 1376
(s), 1264 (m), 1236 (s), 1215 (s), 1156 (m, C=S), 1119 (s), 865 (m),
N-Isopropyl-N-phenyl-NЈ-(benzoyl)thiourea (HL8) (6): White solid.
1
Yield 90%. M.p. 152–154 °C. H NMR (500 MHz, CDCl3): δ = 8.09
Z. Anorg. Allg. Chem. 0000, 0–0
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ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
(s, 1 H, NH), 7.45 (m, 3 H, Ph-H), 7.40 (m, 1 H, Ph-H), 7.31–7.35
to obtain off-white powders (0.45 g, 0.73 mmol, 73%). M.p. 178–
(m, 4 H, Ph-H), 7.25 (m, 2 H, Ph-H), 5.81 (m, 1 H, CH(CH3)2), 1.22
(d, 6 H, CH(CH3)2) ppm. 13C NMR (126 MHz, CDCl3): δ = 179.17
(C=S), 163.62 (C=O), 138.40, 133.48, 132.45, 129.30, 129.02, 128.99,
179 °C. FT-IR (KBr): ν˜ = 3105 (s), 2975 (m), 2934 (m), 2863 (m),
1698 (s), 1610 (w, C=O), 1549 (m), 1439 (s), 1381 (w), 1295 (w),
1256 (m), 1223 (s), 1169 (w), 1122 (m, C=S), 1057 (w), 845 (w)
128.83, 128.66, 127.23 (Ph-C), 53.49 (CH(CH3)2), 20.51 (CH(CH3)2) cm–1. C30H42CuN4O2S2 (618.4): calcd. C, 58.27; H, 6.85; N, 9.06; S,
ppm. FT-IR (KBr): ν˜ = 3194 (w, NH), 2976 (w), 1700 (m, C=O),
1641 (m), 1582 (w), 1513 (s), 1407 (m), 1366 (w), 1350 (m), 1233
(s), 1171 (m), 1153 (m, C=S), 1072 (m), 915 (w), 828 (w), 793 (w),
763 (w), 703 (s), 669 (w), 628 (w), 566 (w) cm–1. C17H18N2OS
(298.4): calcd. C, 68.42; H, 6.08; N, 9.39; S, 10.75%; found C, 68.33;
H, 6.06; N, 9.35; S, 10.86%.
10.37%; found C, 57.99; H, 6.86; N, 8.85; S, 10.22%. Dark green X-
ray quality single crystals of 12 were obtained from a concentrated
THF solution.
X-ray Crystallography: Data were collected with a Bruker SMART
APEX II CCD diffractometer. The diffraction data were obtained by
using graphite monochromated Mo-Kα radiation with a ω-2θ scan tech-
nique at room temperature. The structure was solved by direct methods
cis-CuL12 (7): To a solution of HL1 (1) (0.3825 g, 1.0 mmol) in dichlo-
romethane (15 mL) at room temperature was added an aqueous sodium with SHELX-97.[17] A full-matrix least-squares refinement on F2 was
acetate solution (0.0836 g, 1.0 mmol) under intense stirring within 1 carried out by using SHELXL-97.[17]
h. A suspension of CuBr (0.1415 g, 1.0 mmol) in ethanol was added
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
of the data can be obtained free of charge on quoting the depository
numbers CCDC-1037321 (1), CCDC-1037322 (4), CCDC-1037323
(7·THF), CCDC-1037324 (8), CCDC-1037325 (9), CCDC-1037326
(10), and CCDC-1037327 (12) (Fax: +44-1223-336-033; E-Mail:
deposit@ccdc.cam.ac.uk, http://www.ccdc.cam.ac.uk)
to the reaction mixture drop by drop. An additional 12 h was allowed
to insure the completion of complexation. The resultant precipitates
were filtered, washed with ethanol repeatedly, and dried at 80 °C to
obtain deep green powders (0.3088 g, 0.37 mmol, 37.4%). M.p. 210–
212 °C. FT-IR (KBr): ν˜ = 3433.06 (w), 3052.4 (w), 1590.55 (vw,
C=O), 1488.76 (m), 1428.04 (m), 1393.05 (m), 1287.28 (w), 1238.8
(w), 1149.31 (vw, C=S), 1074.37 (vw), 1032.83 (vw), 884.92 (vw),
780.73 (w), 754.9 (vw), 696.98 (vw), 624.45 (vw) cm–1.
C48H34CuN4O2S2 (826.5): calcd. C, 69.75; H, 4.15; N, 7.69; S, 7.76%;
found C, 69.49; H, 4.10; N, 7.57; S, 7.90%. X-ray quality single crys-
tals of 7 were obtained from a concentrated dichloromethane solution.
Supporting Information (see footnote on the first page of this article):
Molecular structures and packing diagrams in Figures S1–S8. Struc-
tural data in Tables S1 for 1, 4, 7·THF, 8–10, and 12. Spectroscopic
data for 10.
cis-CuL2 (8): The procedure was similar to that for cis-CuL1 (7),
2
2
using HL2 (2) (0. 3485 g, 1.0 mmol), sodium acetate (0.0836 g,
1.0 mmol), and CuCl (0.1032 g, 1.0 mmol). Dark green solid (0.33 g,
0.44 mmol, 44%). M.p. 186–189 °C. FT-IR (KBr): ν˜ = 3436 (w), 3050
(vw), 2976 (vw), 2928 (vw), 1627 (vw, C=O), 1508 (vw), 1487 (vw),
1431 (w), 1407 (w), 1274 (vw), 1237 (vw), 1109 (vw, C=S), 780 (vw),
696 (vw) cm–1. C42H38CuN4O2S2 (758.5): calcd. C, 66.51; H, 5.05; N,
7.39; S, 8.46%; found C, 66.19; H, 5.07; N, 7.23; S, 8.48%. X-ray
quality single crystals of 8 were obtained from a concentrated dichloro-
methane solution.
Acknowledgements
This work was supported by the Research Fund for Teachers of Central
South University (2013JSJJ007), and the Science and Technology
Planning Project of Hunan Province of China (2013FJ2003). Support
of the Deutsche Forschungsgemeinschaft is gratefully acknowledged.
References
cis-CuL4 (9): The procedure was similar to that for cis-CuL1 (7),
2
2
using HL4 (3) (0.3745 g, 1.0 mmol), sodium acetate (0.0836 g,
1.0 mmol), and CuBr (0.1441 g, 1.0 mmol). Deep green solid
(0.4278 g, 0.53 mmol, 52.9%). M.p. 233–235 °C. FT-IR (KBr): ν˜ =
3441.22 (w), 2961.35 (vw), 2917.97 (vw), 1609.50 (vw, C=O),
1475.38 (m), 1427.92 (m), 1371.26 (m), 1288.36 (w), 1254.98 (vw),
1153.77 (vw, C=S), 1073.90 (vw), 1027.99 (vw), 874.84 (vw), 756.01
(vw), 696.74 (vw), 627.19 (vw) cm–1. C46H42CuN4O2S2 (810.5): calcd.
C, 68.16; H, 5.22; N, 6.91; S, 7.91%; found C, 68.11; H, 5.22; N,
6.80; S, 7.94%. X-ray quality single crystals of 9 were obtained from
a concentrated dichloromethane solution.
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found C, 64.38; H, 6.16; N, 7.44; S, 8.67%.
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filtered, washed with ethanol repeatedly, and dried at 50 °C in vacuo
Z. Anorg. Allg. Chem. 0000, 0–0
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Journal of Inorganic and General Chemistry
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ARTICLE
Zeitschrift für anorganische und allgemeine Chemie
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[16] Crystal data for trans-CuL5 (11): monoclinic, P2/c.
a =
2
29.6536(18), b = 13.0638(7), c = 10.3734(5) Å; γ = 100.020(3)°;
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Received: December 20, 2014
Published Online: ᭿
Z. Anorg. Allg. Chem. 0000, 0–0
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Journal of Inorganic and General Chemistry
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S.-Y. Wu, X.-Y. Zhao, H.-P. Li, Y. Yang,*
H. W. Roesky* ................................................................... 1–8
Synthesis and Characterization of N,N-Di-substituted Acyl-
thiourea Copper(II) Complexes
Z. Anorg. Allg. Chem. 0000, 0–0
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