Synthesis and coordination chemistry of novel binucleating macrocyclic ligands with amine-thioether and amine-thiophenolate donor functions

Article abstract of DOI:10.1515/znb-2001-0907

The ability of the aromatic tetraaldehyde 1,2-bis(4-tert-butyl-2,6-diformylphenylsulfanyl)-ethane (1) to function as a precursor in the preparation of binucleating hexaamine-dithiolate ligands has been investigated. Reductive amination of compound 1 with bis(aminoethyl)amine under medium-dilution conditions affords the macrobicyclic hexaamine-dithioether compound L¹. Deprotection of the [1+2] condensation product gives the corresponding 24-membered hexaamine-dithiophenol ligand H₂L². The formulation of L¹ as a macrobicyclic amine-thioether was confirmed by an X-ray crystal structure determination of the tetranuclear nickel(II) complex of L¹, [{(L¹)Ni₂Cl₂}₂(μ-Cl) ₃](BPh₄) (2b). The formulation of the doubly deprotonated form (L²)^2- of H₂L² as a 24-membered amine-thiophenolate ligand was confirmed by an X-ray crystal structure determination of the dinuclear cobalt(III) complex, [(L²)Co^III(μ-OH)](ClO₄)₂ · Cl (3). The preparation and the crystal structures of the new compounds are described.

Full text of DOI:10.1515/znb-2001-0907

Synthesis and Coordination Chemistry of Novel Binucleating Macrocyclic
Ligands with Amine-thioether and Amine-thiophenolate Donor Functions
Marco H. Klingele, Gunther Steinfeld, and Berthold Kersting
Institut für Anorganische und Analytische Chemie der Albert-Ludwigs-Universität,
Albertstraße 21, D-79104 Freiburg, Germany
Reprint requests to Dr. B. Kersting. Fax: +49(0)761 203 5987.
E-mail: kerstber@ sun2.ruf.uni-freiburg.de
Z. Naturforsch. 56 b, 901-907 (2001); received June 5, 2001
Macrocyclic Ligands, Nitrogen, Sulfur
The ability of the aromatic tetraaldehyde l,2-bis(4-rm-butyl-2,6-diformylphenylsulfanyl)-
ethane ( ) to function as a precursor in the preparation of binucleating hexaamine-dithiolate lig-
1
ands has been investigated. Reductive amination of compound 1 with bis(aminoethyl)amine un-
der medium-dilution conditions affords the macrobicyclic hexaamine-dithioether compound L1.
Deprotection of the [1+2] condensation product gives the corresponding 24-membered hexa-
amine-dithiophenol ligand H
2
L2. The formulation of L as a macrobicyclic amine-thioether was
1
confirmed by an X-ray crystal structure determination of the tetranuclear nickel(II) complex
of L 1, [{(LjN iiClili^-Cl^K BPh;) (2b). The formulation of the doubly deprotonated form
(L2)2- of H
2
L as a 24-membered amine-thiophenolate ligand was confirmed by an X-ray
2
crystal structure determination of the dinuclear cobalt(III) complex, [(L )Com(^-OH)](C1 0 4 ) 2
• Cl (3). The preparation and the crystal structures of the new compounds are described.
2
fflu
Introduction
fBu
In recent years much effort has been put in the
synthesis and the investigation of binuclear transi-
tion metal complexes. The pronounced interest in
these compounds is due to both their biological rel-
evance as simple model compounds for the active
sites of certain metalloenzymes [1] and their intrigu-
ing magnetic and electronic properties [2]. Macro-
cyclic ligands are particularly suited for the synthe-
sis of such complexes as they are more stable than
their acyclic counterparts and the two metal ions are
fixed in close proximity which has important im-
plications for the metal-metal interactions [3] and
the binuclear metal reactivity [4]. In the past most
of the pertinent studies had focused on phenolate-
based ligands [5 - 8] and it is only recently that the
coordination chemistry of the corresponding thio-
phenolate-based macrocycles has been investigated
[9-12].
NH
S
HI
N—\
NH SH N H ^
r
c
NH
HN
NH
NH
HN
C NH
HN“^
SH NH-^
6 HCI
fBu
L1
H2L 6HCI
Scheme 1. Synthesis of L1 anAd UH?L : (i) HN(CH
2
CH -
2
__
T 2.
NH2)2, CFbCl2, C
9
H
5
OH, 12 h; then NaBH4, r. t.; (ii) Na,
liq. NH3, THF, -78 °C; conc. HCI, H
2
0.
with a,o;-diamines (see Scheme 1). In initial studies
focused on condensation reactions with ethylenedi-
amine and propylenediamine, however, only [2+4]
condensation products could be obtained, not the
desired [1+2] macrocycles. As the NH2-functions
in ethylenediamine and propylenediamine are sep-
arated by C2 and C3 alkyl chains, we have inves-
tigated the possibility of generating the [1+2] con-
densation product by using bis(aminoethyl)amine,
where the two NH2 functions are separated by a
longer -CH2CH2NHCH2CH2- alkyl chain. We re-
port here on our findings.
Recently, we reported on a novel synthesis of
macrocyclic amine-thiophenolate ligands [12, 13].
Our approach makes use of the air-stable pre-
cursor 1,2-bis(4-terf-butyl-2,6-diformylphenylsul-
fanyl)ethane (1 ) which can be readily condensed
0932-0776/01/0900-0901 $ 06.00 © 2001 Verlag der Zeitschrift für Naturforschung, Tübingen • www.znaturforsch.com
K
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

902
M. H. Klingele et al. ■Novel Binucleating Macrocyclic Ligands
1. 2 x Ni"ci2 6H20
2. UCIO4
Results and Discussion
L
------------------
-
[{(L 1)N i"2C I2}2(n -C I)3 ](C I0 4 )
(1 a )
(1b)
1+
Ligand syntheses
2a
N a B P h 4
For the synthesis of the thiophenol ligand H2L2
(Scheme 1) the tetraaldehyde 1 was used as starting
material. Earlier attempts to obtain a [2+1] product
from the condensation of 1 with either ethylene-
diamine or propylenediamine had failed and only
[4+2] products had been obtained [12, 13]. Despite
these findings the condensation of 1 with diethylen-
etriamine under medium-dilution conditions was
carried out and afforded, after subsequent sodium
borohydride reduction of the tetraimine-dithioether
intermediate, a single compound L1 in 95% yield.
On the basis of the elemental analysis and the NMR
data the assignment of a [2+1] or [4+2] constitu-
tion for the isolated compound was not possible
due to the fact that both possible products would
give rise to identical analytical data. However, the
formulation of L1 as a macrobicyclic amine-thio-
ether could be unambiguously confirmed by single
crystal X-ray structure analysis of one of its metal
complexes (vide infra). Removal of the protecting
ethylene group was achieved with sodium in liquid
ammonia followed by acidic work-up. This gave the
bis-thiophenol ligand H2L2 as the hexa-hydrochlo-
ride in 63% yield [14].
2a
[{(L1)Ni"2CI2}2(n-CI)3](BPh4)
2b
1. 2 x C o X I26H20
2
NEtyMeOH
,
...
H2L 6HCI - -
*
l
-
t(L )C0 2(n-0H)](CI04)2CI
(2)
3
According to this procedure the new ligand is
obtained in good overall yield without the need
of metal templates. The bis-thiophenol H2L2 can
be isolated and stored as the hydrochloride and re-
acted with metal ions. As their nitrogen donors are
no longer imine functions these ligands are more
flexible, stable towards hydrolysis and ring size al-
terations cannot occur. Moreover, as the thiophenol
functions are masked during the synthesis and liber-
ated only in the last step the formation of disulfides
and other by-products arising from the oxidation of
the sulphur atoms is avoided.
complex [{(L1)Ni2Cl2}2(^-Cl)3]Cl (2a) was ob-
tained as a blue powder in 82% yield (eq. (la)).
The tetraphenylborate salt [{(L ^^C h^O ^-C l^]-
(BPI14) (2b) was prepared by addition of NaBPli4 to
a solution of 2a in acetonitrile (eq. (lb)). Complex
2b exhibits excellent solubility in dichloromethane,
while it is virtually insoluble in methanol. Thus,
slow evaporation of a solution of the complex in a
mixed CH2CI2 / CH3OH solvent system produced
large single crystals of 2b • 8 MeOH.
Preparation o f m etal com plexes
The reaction of H2L2 6 HCl, C0CI2 •6 H2O and
NEt3 in methanol in a 1 :2:8 molar ratio initially pro-
duced a pale-red solution, which can be attributed
to the formation of a dicobalt(II) complex. Upon
exposure to air the color of the solution quickly
changed from red to brown. The dicobalt(III) com-
In order to confirm the macrocyclic nature of the
new ligands the metal complexes [{(L1)Ni2Cl2}2(/i-
Cl)3](BPh4) (2b) and [(L2)Coni2(^-OH)](C104)2Cl
(3) were prepared and characterized by single crys-
tal X-ray structure determination. The reaction of L1
with two equivalents of NiCl2 • 6 H2O in methanol
plex [(L
2
)Com(/i-OH)](C
1
0
4
)
2
C1 (3) was isolated
at ambient temperature takes place readily to give a by adding an excess of LiC104 (eq. (2)). Com-
pale blue solution. Upon stirring for 15 min the plex 3 is diamagnetic and exhibits good solubil-
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

M. H. Klingele et al. • Novel Binucleating Macrocyclic Ligands
903
Fig. 1. Structure of the complex [{(L^NiiCb^Ai-COa]1* in crystals of 2b •
8
MeOH with thermal ellipsoids drawn
at the 50% probability level, tert-Butyl groups and hydrogen atoms are omitted for clarity.
Table 1. Selected bond lengths [A] and angles [°] in 2b.
Table 1 (continued).
N(l)-Ni(l)-N(2)
N(l)-Ni(l)-N(3)
N(l)-Ni(l)-Cl(5)
N(l)-Ni(l)-Cl(6) 172.56(15) N(7)-Ni(3)-Cl(5) 173.69(13)
N(l)-Ni(l)-Cl(7)
N(2)-Ni(l)-N(3)
N(2)-Ni(l)-Cl(5) 174.8(2)
N(2)-Ni(l)-Cl(6)
N(2)-Ni(l)-Cl(7)
N(3)-Ni(l)-Cl(5) 102.08(14) N(9)-Ni(3)-Cl(5)
N(3)-Ni(l)-Cl(6)
N(3)-Ni(l)-Cl(7) 169.82(14) N(9)-Ni(3)-Cl(7) 167.61(14)
Cl(5)-Ni(l)-Cl(6) 86.44(6) Cl(5)-Ni(3)-Cl(6)
Cl(5)-Ni(l)-Cl(7) 85.60(6) Cl(5)-Ni(3)-Cl(7)
Cl(6)-Ni(l)-Cl(7) 83.11(6) Cl(6)-Ni(3)-Cl(7)
84.8(2)
96.7(2)
N(7)-Ni(3)-N(8)
N(7)-Ni(3)-N(9)
85.0(2)
98.3(2)
92.80(14)
Ni(l)-N(l)
Ni(l)-N(2)
Ni(l)-N(3)
Ni(l)-Cl(5)
Ni(l)-Cl(6)
Ni(l)-Cl(7)
Ni(2)-N(4)
Ni(2)-N(5)
Ni(2)-N(6)
Ni(2)-S(l)
Ni(2)-Cl(l)
Ni(2)-Cl(2)
Ni(l)--Ni(3)
2.107(5)
2.068(5)
2.134(5)
2.378(2)
2.446(2)
2.504(2)
2.126(5)
2.043(5)
2.059(5)
2.384(2)
2.459(2)
2.529(2)
3.070(2)
Ni(3)-N(7)
Ni(3)-N(8)
Ni(3)-N(9)
Ni(3)-Cl(5)
Ni(3)-Cl(6)
Ni(3)-Cl(7)
Ni(4)-N(10)
Ni(4)-N(ll)
Ni(4)-N(12)
Ni(4)-S(3)
Ni(4)-Cl(3)
Ni(4)-Cl(4)
2.113(5)
2.064(5)
2.140(5)
2.461(2)
2.382(2)
2.520(2)
2.092(5)
2.061(5)
2.042(5)
2.426(2)
2.457(2)
2.527(2)
92.99(14) N(7)-Ni(3)-Cl(6)
N(7)-Ni(3)-Cl(7)
N(8)-Ni(3)-N(9)
N(8)-Ni(3)-Cl(5)
N(8)-Ni(3)-Cl(6) 172.7(2)
N(8)-Ni(3)-Cl(7)
90.16(13)
82.8(2)
95.44(15)
89.44(15)
82.9(2)
95.2(2)
89.7(2)
89.0(2)
87.99(13)
90.64(14) N(9)-Ni(3)-Cl(6) 104.41(14)
86.00(6)
83.55(6)
84.06(6)
ity in polar solvents such as methanol, acetonitrile
and dimethylformamide. A thoroughly dried sample
showed a strong, but broad infrared absorption band
at 3142 cm-1 , which was assigned to the ^(O-H)-
stretching frequency of the bridging OH group. Re-
crystallization from ethanol afforded 3 • 2 EtOH as
dark-brown crystals, which were subjected to single
crystal X-ray structure analysis.
N(10)-Ni(4)-N(ll) 83.6(2)
N( 10)-Ni(4)-N( 12) 161.5(2)
98.97(14) N(10)-Ni(4)-S(3) 100.30(14)
N(4)-Ni(2)-N(5)
N(4)-Ni(2)-N(6) 160.7(2)
N(4)-Ni(2)-S(l)
N(4)-Ni(2)-Cl(l)
N(4)-Ni(2)-Cl(2)
N(5)-Ni(2)-N(6)
83.3(2)
99.5(2)
82.5(2)
84.6(2)
N(10)-Ni(4)-Cl(3)
N(10)-Ni(4)-Cl(4)
98.71(14)
84.71(14)
N(ll)-Ni(4)-N(12) 84.0(2)
N(ll)-Ni(4)-S(3) 175.9(2)
N(5)-Ni(2)-S(l) 177.5(2)
N(5)-Ni(2)-Cl(l)
N(5)-Ni(2)-Cl(2)
N(6)-Ni(2)-S(l)
N(6)-Ni(2)-Cl(l)
N(6)-Ni(2)-Cl(2)
S(l)-Ni(2)-Cl(l)
S(l)-Ni(2)-Cl(2)
83.0(2)
94.5(2)
N(ll)-Ni(4)-Cl(3)
N(ll)-Ni(4)-Cl(4)
93.53(14) N(12)-Ni(4)-S(3)
93.87(14) N(12)-Ni(4)-Cl(3)
82.66(15)
96.37(15)
92.60(14)
93.21(15)
D escription o f the crystal structure o f 2b • 8 M eOH
N(12)-Ni(4)-Cl(4) 83.13(14)
83.53(14)
95.60(6) S(3)-Ni(4)-Cl(3)
S(3)-Ni(4)-Cl(4)
95.27(6)
85.46(6)
86.85(6)
Crystallographic characterization of complex 2b
• 8 MeOH confirmed the crystal structure to con-
sist of tetranuclear [{(L1)2NiCl2}2(/i-Cl)3]1+ cat-
ions, tetraphenylborate anions and methanol sol-
vent molecules of crystallization. The asymmetric
unit consists of one formula unit. Fig. 1 shows the
Cl(l)-Ni(2)-Cl(2) 176.54(6)
Cl(3)-Ni(4)-Cl(4) 176.30(6)
Ni(l)-Cl(5)-Ni(3) 78.74(5) Ni(l)-Cl(6)-Ni(3)
Ni(l)-Cl(7)-Ni(3) 75.34(6)
78.97(5)
clear complex cation. Although the complex does
not possess crystallographically imposed symme-
structure of the tetranuclear nickel complex. Two try, its idealized symmetry is C2. Table 1 shows that
the bond lengths and angles of the two binuclear
subunits are more or less identical.
binuclear {(L ^ I^ C ^ }2* subunits are connected
via three chloro bridges to generate the tetranu-
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

904
M. H. Klingele et al. • Novel Binucleating Macrocyclic Ligands
N(4)
Cl(2)(
N(5)^k
i y
äCI(5)
^
l^ (2)
J ^ ) S(21
^ S(1)
|CI(6)
N(3) (
Fig. 2. Structure of the binuclear
!)CI(1)
.Nid)
{(L')Ni
2
Cl }2+-subunit in crystals of
2
N(6)
2b • MeOH with thermal ellipsoids
8
drawn at the 50% probability level.
tert-Butyl groups and hydrogen atoms
are omitted for clarity. The other sub-
unit is connected via the three bridging
chloride ligands C1(5)-C1(7).
N(1)V
K
\ ö )
m 2 )
The dimerization of the two {(L1)Ni2Cl2}2+-sub-
units is due to the specific coordination mode of L1
(Fig. 2). Only one nickel ion (Ni(2)) resides within
the cavity of the amine-thioether ligand. It is pseu-
do-octahedrally coordinated by three secondary ni-
trogen atoms and one thioether sulfur atom of L1
and two chloro ligands. The three nitrogen atoms
are arranged in a meridional fashion. The two halide
ions are found in trans dispositions. The thioether
sulfur atom is in a trans position to N(5). The sec-
ond lateral bis(aminoethyl)amine unit of L1 coor-
dinates facially. Remarkably, the second thioether
atom of L1 does not participate in coordination
to the metal atoms. Thus, the complexes dimerize
via three chloro-briges between N i(l) and Ni(3) to
generate a N3Nin(/i-Cl)3NinN3 core with a pseu-
do-confacial bioctahedral geometry. The average
metal-ligand bond lengths (Ni-N 2.087(5) Ä, Ni-
S 2.405(2) A, Ni-Ou-Cl) 2.449(2), Ni-Cl 2.493(2)
show no unusual features and compare well with
those of other octahedral nickel(II) complexes [15].
C(25)
Fig. 3. Structure of the /z-OH complex in crystals of 3 •
2 EtOH with thermal ellipsoids drawn at the 50% prob-
Description of the crystal structure of 3 • 2 EtOH
The crystal structure of 3-2EtOH was found to ability level, tert-Butyl groups and hydrogen atoms are
omitted for clarity.
consist of discrete, dinuclear [(L2)Coni2(/x-OH)]3+
trications. The asymmetric unit contains one trica-
tion, two perchlorate anions, a chloride anion, and
two ethanol molecules of solvent of crystallization.
Fig. 3 shows the structure of the dinuclear cobalt(III)
complex, Table 2 lists selected bond lengths and
angles.
Although the complex does not possess crystal-
lographically imposed symmetry, its idealized sym-
metry is Cs, where one halfof the molecule is related
to the other by a mirror plane that passes through
the two bridging thiolate sulfur atoms and the oxy-
gen atom of the OH unit. Thus the two cobalt(III)
ions are symmetrically bridged by the hydroxide
group. The Co-OH bond length of 1.927(5) Ä is
normal for hydroxo-bridged Co111 complexes [16].
Likewise, the average Co-N- and Co-S-distances
at 1.979(5) and 2.271(2) A, respectively, show no
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

M. H. Klingele et al. ■Novel Binucleating Macrocyclic Ligands
Table 2. Selected bond lengths [A] and angles [°] in 3.
905
plosive and should therefore be prepared only in small
quantities and handled with appropriate care.
Co(l)-0(l)
Co(l)-N(l)
Co(l)-N(2)
Co(l)-N(3)
Co(l)-S(l)
Co(l)-S(2)
Co(l)-Co(2)
1.924(4)
1.977(5)
1.986(5)
1.978(5)
2.275(2)
2.271(2)
2.7936(12)
1.930(5)
1.958(5)
1.976(5)
1.996(6)
2.268(2)
2.271(2)
Co(2)-0(l)
Co(2)-N(4)
Co(2)-N(5)
Co(2)-N(6)
Co(2)-S(l)
Co(2)-S(2)
Preparation of tetraaldehyde (1): To a suspension of
anhydrous potassium carbonate (20.73 g, 150.0 mmol)
in vV,/V-dimethylformamide (150 cm3) was added 1,2-
ethanedithiol (4.71 g, 50.0 mmol) and 2-bromo-5-tert-
butylbenzene-l,3-dicarbaldehyde (26.91 g, 100.0 mmol)
and the reaction mixture was stirred at 50 °C for 24 h.
After dropwise addition of water (500 cm3), the result-
ing precipitate was filtered off and washed with water.
Drying in vacuo gave 1 as a pale yellow solid (22.44 g,
95%). - M. p. 176 - 178 °C (dichloromethane / cyclohex-
ane). - 'H NMR (200 MHz, CDC13): 6 = 1.31 (s, 18 H,
ArC(CH3)3), 2.96 (s, 4 H, ArSCH2), 8.11 (s, 4 H, s, ArH),
176.3(2)
94.4(2)
86.2(2)
81.22(14)
81.74(13) 0(l)-Co(2)-S(2)
85.8(2)
97.6(2)
95.1(2)
98.2(2)
0(l)-Co(2)-N(4)
0(l)-Co(2)-N(5)
0(l)-Co(l)-N(l)
0(l)-Co(l)-N(2)
0(l)-Co(l)-N(3)
0(l)-Co(l)-S(l)
0(l)-Co(l)-S(2)
N(l)-Co(l)-N(2)
N(l)-Co(l)-N(3)
N(l)-Co(l)-S(l)
N(l)-Co(l)-S(2)
87.0(2)
92.6(2)
0(l)-Co(2)-N(6) 175.0(2)
0(l)-Co(2)-S(l) 81.26(13)
81.60(13)
85.6(2)
97.8(2)
167.5(2)
91.3(2)
86.6(2)
N(4)-Co(2)-N(5)
N(4)-Co(2)-N(6)
N(4)-Co(2)-S(l)
N(4)-Co(2)-S(2)
N(5)-Co(2)-N(6)
N(5)-Co(2)-S(l)
10.67 (s, 4 H, CHO). - 1 3 C{
6 = 30.9, 35.2, 38.5, 131.3, 136.9, 138.3, 153.9, 191.0. -
(470.65): calcd. C 66.37, H 6.72, S 13.53;
1
H} NMR (50 MHz, CDC13):
N(2)-Co(l)-S(2) 174.7(2)
N(2)-Co(l)-S(l)
N(2)-Co(l)-N(3)
C
2 6
H
3
o0
4
S2
100.5(2)
84.9(2)
99.2(2)
N(5)-Co(2)-S(2) 173.5(2)
found C 66.58, H 6.60, S 13.33.
Preparation of macrobicyclic thioether L1: Solutions
of 1 (7.06 g, 15.0 mmol) in dichloromethane (150 cm3)
and of diethylenetriamine (3.10 g, 30.0 mmol) in ethanol
(150 ml) were added simultaneously over a period of
N(3)-Co(l)-S(l) 166.6(2)
N(6)-Co(2)-S(l)
N(6)-Co(2)-S(2)
S(l)-Co(2)-S(2)
94.0(2)
99.4(2)
82.69(7)
N(3)-Co(l)-S(2)
S(l)-Co(l)-S(2)
91.2(2)
82.57(7)
6
h to a mixture of dichloromethane (450 cm3) and
unusual features and compare well with those of
ethanol (150 cm3). After complete addition, the reac-
tion mixture was stirred at room temperature for 18 h.
The dichloromethane was then removed at reduced pres-
sure and a solution of sodium borohydride (4.54 g,
120.0 mmol) in ethanol (150 cm3) was added. After stir-
related ComN3S3 complexes [17].
Conclusions
By means of a straightforward procedure we were
able to obtain the new 24-membered macrocyclic
bis-thiophenol ligand H2L in good overall yield. In
comparison to the conventional route applied for
the synthesis of binucleating macrocyclic ligands
the necessity of using metal templates has been
eliminated. The new ligands are stable and isolable
and can be stored and used for complexation re-
actions.
ring at room temperature for h, the reaction mixture was
2
acidified to pH 1 with conc. hydrochloric acid and the re-
sulting colourless suspension was evaporated to dryness.
Water (150 cm3) and dichloromethane (300 cm3) were
added to the residue, the pH of the aqueous phase was
adjusted to 13 with 3 M aqueous potassium hydroxide
and the heterogeneous mixture was stirred vigorously for
30 min. The layers were separated and the aqueous phase
was extracted with dichloromethane (5 x 50 cm3). The
combined organic fractions were dried over anhydrous
Experimental Section
sodium sulphate. Evaporation of the solvent gave L as a
1
yellowish foamy solid (8.80 g, 95%). - M. p. 223 - 225 °C
(dichloromethane / methanol). - ‘H NMR (200 MHz,
Materials and methods: 2-Bromo-5-ter/-butylbenz-
ene-1,3-dicarbaldehyde was prepared as described in the
literature [18]. Compound 1 was prepared according to
a modified literature procedure [12]. All syntheses were
carried out under a protective atmosphere of argon. Melt-
ing points were determined in open glass capillaries
and are uncorrected. NMR spectra were recorded on a
Bruker AVANCE DPX-200 spectrometer at 300 K. Chem-
ical shifts refer to solvent signals. Infrared spectra were
recorded on a Bruker VECTOR 22 FT-IR-spectrometer
CDC13): 6 = 1.24 (s, 18 H, ArC(CH3)3), 2.34 (s,
NH), 2.81 - 2.91 (m, 16 H, N(CH CH2)2), 3.15 (s, 4 H,
ArSCH2), 3.87 (s, H, ArCH?N), 7.21 (s, 4 H, ArH). -
6
H,
2
8
1 3 C{'H} NMR (50 MHz, CDC13): 6 = 32.2, 35.5, 38.1,
49.9,50.4,55.0,128.4,131.0,145.1,153.1.-C 34H56N6S2
(612.99): calcd. C 66.62, H 9.21, N 13.71, S 10.09; found
C 66.28, H 8.97, N 14.01, S 10.30.
Preparation ofthe bis-thiophenol ligand H2L2 ■6 HCl:
and electronic absorption spectra on a Jasco V-570 UV / To a solution of sodium (3.45 g, 150.0 mmol) in liq-
VIS / NIR spectrophotometer. Elemental analyses were uid ammonia (150 cm3) was added a solution of L
1
(3.06 g, 5.00 mmol) in tetrahydrofuran (50 cm3) drop-
wise at -78 °C. The resulting blue reaction mixture was
carried out by the microanalytical laboratory of this uni-
versity. CAUTION! Perchlorate salts are potentially ex-
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

906
M. H. Klingele et al. • Novel Binucleating Macrocyclic Ligands
stirred at -78 °C for 1 h before solid ammonium chlo- reaction mixture to air initiated a colour change to dark
ride (8.02 g, 150.0 mmol) was added in small portions red-brown. After stirring for 2 h, the product was precipi-
at -78 °C to destroy excess reducing agent. The resulting tated by the addition of solid lithium perchlorate (2.13 g,
colourless suspension was allowed to warm to room tem- 20.0 mmol). The microcrystalline solid was filtered off
and washed with little methanol and diethyl ether. Dry-
ing in vacuo gave 3 as a brown solid (580 mg, 60%),
perature. After 12 h, the remaining solvent was distilled
off at reduced pressure. The residue was taken up in wa-
ter (50 cm3), conc. hydrochloric acid (5 cm3) was added which decomposes without melting. - UV/vis (CH CN):
3
and the mixture was evaporated to dryness. To remove A(lg e) = 428 (3.58), 538 (3.03). - IR(KBr): ^ = 3431 (O-
sodium chloride and ammonium chloride from the prod- H), 3192,1120,1107,1090 cm“ 1. - 1H NMR (200 MHz,
uct, the residue was triturated with methanol (3 x 50 cm3)
and filtered. Evaporation of the solvent gave the product 4.30 - 2.50 (m, 20 H),4.60 (m, 2 H), 4.90 (m, 2 H), 5.95
DMSO-de): 6 = 1.26 (s, 9 H, CH3), 1.29 (s, 9 H, CH3),
as a colourless solid (2.54 g, 63%). - M.p. > 300 °C
(methanol). - ’H NMR (20 0 MHz, D 0): 6 = 1.13 (s,
18 H, ArC(CH3)3), 3.33 - 3.45 (m, 16 H, N(CH CH2)2),
4.46 (s, H, ArCH N), 7.52 (s, 4 H, ArH). - 1 3 C{'H}
NMR (50 MHz, D 0): 6 = 30.6, 34.5, 42.4, 44.3, 51.5,
131.3,133.7,152.4, one carbon signal was not observed.- (954.16) calcd. C 40.28, H 5.60, N 8.81, S 6.72; found
oCl (805.72) calcd. C 47.70, H 7.51, N 10.43, C 39.06, H 5.72, N 8.72, S 6.45. - Single crystals of 3
(m, 2 H), 7.13 (m, 2 H), 7.32 (s, 2 H, ArH), 7.46 (s, 2
H, ArH). - 1 3 C{!H} NMR (50.3 MHz, DMSO-d6): <5=
31.59, 31.71, 35.50, 35.66, 52.63, 53.07, 56.12, 56.99,
57.06,57.11,124.49,127.58 (CH), 128.40 (CH), 131.64,
2
2
8
2
2
139.43, 142.85, 151.59, 152.01. - C3 2
H
5 3 Cl
3
Co
2
N
6
0
9
S
2
C
3 2
H
6
6
N
6
S
2
S 7.96; found C 47.41, H 7.25, N 10.07, S 7.56.
• 2 C
2
H5 0H suitable for X-ray crystal structure analysis
were obtained from a dilute solution of 3 in ethanol by
Preparation of [{(iJ )Ni2Ch}2(n-Cl)3]Cl (2a): To a so-
slow evaporation of the solvent.
lution of L (613 mg, 1.00 mmol) in methanol (20 cm3)
1
was added a solution of nickel(II) chloride hexahydrate
(475 mg, 2.00 mmol) in methanol (5 cm3) and the reaction
mixture was stirred at room temperature for 15 minutes.
The resulting blue precipitate was filtered off and washed
with little methanol and diethyl ether. Drying in vacuo
gave 2a as a blue powder (719 mg, 82 %), which decom-
Crystal structure determinations: Single crystals of 2b
•
8
CH3OH suitable for X-ray structure analysis were
obtained by slow evaporation of a solution of the com-
pound in a CH Cl /Me0H mixed solvent system. Sin-
2
2
gle crystals of 3 • 2 EtOH were grown by recrystalliza-
tion from ethanol. The crystals were mounted on glass
fibers using perfluoropolyether oil. Intensity data were
collected at 180(2) K, using a Bruker SMART CCD
diffractometer. Graphite monochromated Mo-/lq radia-
tion (A = 0.71073 A) was used throughout. The data were
processed with SAINT [19] and corrected for absorption
using SADABS [20] (transmission factors: 1.00 - 0.65 for
2b, 1.00 - 0.92 for 3). The structures were solved by direct
poses without melting. - UV/vis (CH CN): Amax (lg e) =
3
370 nm (2.28), 586 (2.02), 1075 (1.70). - IR (KBr): z/ =
3204, 2959, 2870, 1466, 1451, 1024, 959, 942 cm "1. -
C
6 8 H!12 Cl
8
N
12 Ni
4
S4 (1744.38): calcd. C 46.82, H 6.47,
N 9.64, S 7.35; found C 46.21, H 6.41, N 10.20, S 7.08.
Preparation of [{(L1)Ni2Cl2}2(p-Cl)3]BPh4 (2b): To
a solution of 2a (174 mg, 0.100 mmol) in acetoni-
trile (50 cm3) was added solid sodium tetraphenylborate
(342 mg, 1.00 mmol). After the solvent volume had been
reduced to approximately one fifth at reduced pressure,
the resulting blue precipitate was filtered off, washed with
little acetonitrile and diethyl ether. Drying in vacuo gave
methods by using the program SHELXS
-
8
6
[21] and re-
fined by full-matrix least-squares techniques against F 2
using SHELXL-93 [22], Platon was used to search for
higher symmetry. Hydrogen atoms were assigned to ide-
alized position and given a thermal parameter
1
. 2 times
(1.5 for CH
attached.
3
groups) that of the atoms to which they are
2b as a pale blue powder (179 mg,
tals of 2b • CH3OH suitable for X-ray crystal structure
analysis were obtained by slow evaporation of a solution
of 2b in CH C1 / MeOH. Being stored in air at room tem-
perature, these crystals decomposed within a short period
of time with the loss of the solvent of crystallization.
8
8
%). - Single crys-
8
Crystal data for 2b • 8 CH3OH: CiooH]64BCl7Ni2Ni4-
(Mr = 2284.47); crystal size 0.28 0.16
0.08 mm3; triclinic, space group P I (no. ), with a =
13.516(3), b = 19.072(4), c = 23.997(5) A, a = 73.54(3),
ß = 82.92(3), = 79.84(3)°, Z = 2, V = 5821.7(22) A3,
2
2
0
8
S4
x
x
2
7
Preparation of [(L2)Co'II2(n-OH)]Cl(Cl04)2 (3): A
solution of cobalt(II) chloride hexahydrate (476 mg,
Sealed = 1.303 ge m-3, 26>max = 56.72°, /u(Mo-Ka) =
0.924 mm-1, 52989 reflections measured, 27177 unique
(^im= 0.0548), 12113 observed reflections [/>2a(/)]. All
non-hydrogen atoms were refined anisotropically except
for the carbon atoms of the disordered tBu groups and the
2
. 0
0
mmol) in methanol ( 1
0
cm3) was added dropwise
to a suspension of H
2
L
2
•
6
H20 (806 mg, 1.00 mmol) in
methanol (50 cm3) and the resulting bluish-green solution
was stirred at room temperature for 30 min. A solution
of triethylamine (810 mg, 8.00 mol) in methanol (5 cm3) oxygen and carbon atoms of the methanol molecules of
was then added to give a red solution. Exposure of the solvent of crystallization. A split atom model was applied.
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM

M. H. Klingele et al. • Novel Binucleating Macrocyclic Ligands
907
The site occupancies of the respective orientations were the two positions were fixed at 0.50 for Cl(2), 0(6), 0(7),
0(6)', 0(7)', and 0.50 for Cl(3), 0(8), 0(9), 0(10), 0(11).
No hydrogen atoms were calculated for the bridging OH
group. Final residuals: R 1 = 0.0753, wR 2 = 0.2278 (for
5186 reflections with I > 2a(I)), RI = 0.1452, wR2 =
refined as follows: 0.48(1) (for C30a, C31a, C32a) and
0.52(1) (for C30b, C31b, C32b); 0.47(1) (for C60a, C61a,
C62a) and 0.53(1) (for C60b, C61b, C62b). No hydrogen
atoms were calculated for the OH groups of the methanol
molecules. Final residuals: R\ = 0.0753, wR2 = 0.2278 0.2650 (for all data); parameter 486; largest difference
(for 5186 reflections with I > 2a(/)), R\ = 0.1452, wR2 = peak/hole 1.448 / -1.047 eA~3. Crystallographic data
0.2650 (for all data); parameter 486; largest difference (excluding structure factors) for the structure(s) reported
peak/hole 1.448 / - l . 047 eA~3.
in this paper have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publica-
Crystal data for 3 • 2 EtOH: C3 6
H
6 5 CI
3
C
0
2
N
6
O
1 1
S
2
(Mr = 1046.27); crystal size 0.45 x 0.38 x 0.25 mm3; tion no. CCDC-164431 (2b) and -164432 (3). Copies of
the data can be obtained free of charge on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax:
monoclinic, space group C 2/c (no. 15), with a =
19.090(4), b = 20.219(4), c = 25.257(5) h ,ß = \ 10.23(3)°,
Z= 8, V= 9147.3(32) A3, pcaicd =1.519 g-cnT3, 20max = (+44)1223 336-033; e-mail: deposit@ccdc.cam.ac.uk).
56.62°, //(Mo-Ka) = 1.054 mm- 1,28804 reflections mea-
sured, 10936 unique (/?im = 0.0425), 5186 observed re-
flections [/> 2a(I)]. All non-hydrogen atoms were refined
Acknowledgements
This work was supported by the Deutsche Forschungs-
gemeinschaft. The authors thank Prof. H. Vahrenkamp
for his generous support. Technical assistance from Mr.
C. Mattes is also gratefully acknowledged.
anisotropically except for the oxygen atoms of the CIO
anions and the oxygen and carbon atoms of the ethanol
molecules of solvent of crystallization. One C - is dis-
4
“
1
0 4
ordered over two positions. The site occupancy factors for
[9] A. J. Atkins, A. J. Blake, M. Schröder, J. Chem.
Soc., Chem. Commun. 1662 (1993).
[10] S. Booker, P. D. Croucher, F. M. Roxburgh, J. Chem.
Soc., Dalton Trans. 3031 (1996).
[11] A. Christensen, H. S. Jensen, V. McKee, C. J.
McKenzie, M. Munch, Inorg. Chem. 36, 6080
(1997).
[1] a) N. Sträter, W. N. Lipscomb, T. Klabunde,
B. Krebs, Angew. Chem. 108, 2158, (1996); b) A. L.
Feig, S. J. Lippard, Chem. Rev. 94, 759 (1994);
c) R. H. Holm, P. Kennepohl, E. I. Solomon, Chem.
Rev. 96, 2239 (1996); d) D. E. Wilcox, Chem. Rev.
96, 2435 (1996); e) B. J. Wallar, J. D. Lipscomb,
Chem. Rev. 96, 2625 (1996).
[12] B. Kersting, G. Steinfeld, T. Fritz and J. Hausmann,
Eur. J. Inorg. Chem. 2167 (1999)
[13] B. Kersting, Z. Naturforsch. 55b, 1379 (2000).
[14] For a closely related amine-phenol ligand see:
W. Yan, C. Ma, J. Wu, W. Zhang, D. Jiang, Inorg.
Chim. Acta 287, 212(1999).
[15] a) B. Kersting, Eur. J. Inorg. Chem. 2157 (1999);
b) B. Kersting, G. Steinfeld, J. Hausmann, Eur. J.
Inorg. Chem. 179(1999).
[16] T. Laier, J. Springborg, Acta Chem. Scand. A35,
145 (1981).
[17] B. Kersting, D. Siebert, D. Volkmer, M. J. Kolm,
C. Janiak, Inorg. Chem. 38, 3871 (1999).
[18] M. H. Klingele, B. Kersting, Z. Naturforsch. 56b,
437 (2001).
[19] SAINT, Version 4.050, Siemens Analytical X-ray
Instruments Inc., Madison, WI (1995).
[20] G. M. Sheldrick, SADABS, University of Göttingen
(1997).
[2] a) T. Beissel, T. Glaser, F. Kesting, K. Wieghardt, B.
Nuber, Inorg. Chem. 35, 3936 (1996); b) T. Beissel,
F. Birkelbach, E. Bill, T. Glaser, F. Kesting, C. Krebs,
T. Weyhermüller, K. Wieghardt, C. Butzlaff, A. X.
Trautwein, J. Am. Chem. Soc. 118, 12376 (1996).
[3] a) K. K. Nanda, L. K. Thompson, J. N. Bridson,
K. Nag, J. Chem. Soc., Chem. Commun. 1337
(1994); b) K. K. Nanda, R. Das, L. K. Thomp-
son, K. Venkatsubramanian, P. Paul, K. Nag, Inorg.
Chem. 33, 1188(1994).
[4] a) P. Zanello, S. Tamburini, P. A. Vigato, G. A. Maz-
zocchin, Coord. Chem. Rev. 77, 165 (1987); b) P. A.
Vigato, S. Tamburini, D. E. Fenton, Coord. Chem.
Rev. 106, 25 (1990).
[5] N. V. Gerbeleu, V. B. Arion, J. Burgess, Template
Synthesis of Macrocyclic Compounds, Wiley-VCH,
Weinheim (1999).
[6] N. H. Pilkington, R. Robson, Aust. J. Chem. 23,2225
(1970).
[21] G. M. Sheldrick, Acta Crystallogr. A46,467 (1990).
[22] G. M. Sheldrick, SHELXL-93; University of Göt-
tingen (1993).
[7] H. Okawa, H. Furutachi, D. E. Fenton, Coord. Chem.
Rev. 174, 51 (1998).
[8] A. J. Blake, T. I. Hyde, R. S. E. Smith, M. Schröder,
J. Chem. Soc., Chem. Commun. 334 (1986).
Brought to you by | New York University Bobst Library Technical Services
Authenticated
Download Date | 7/28/15 8:52 PM