Synthesis of non-symmetrically substituted tetraimine macrocyclic complexes of copper(II) and nickel(II)

Article abstract of DOI:10.1016/j.ica.2012.10.027

The non-symmetrically functionalized neutral 6,13-substituted-1,4,8,11- tetraazacyclotetradeca-4,6,11,13-tetraene complexes of copper(II) and nickel(II) were synthesized by mesylation of symmetric diol derivatives in neat, anhydrous pyridine at 0°C. The p

Full text of DOI:10.1016/j.ica.2012.10.027

Inorganica Chimica Acta 395 (2013) 160–168
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Inorganica Chimica Acta
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Synthesis of non-symmetrically substituted tetraimine macrocyclic complexes
of copper(II) and nickel(II)
⇑
´
Mateusz Wozny, Iwona Mames, Bohdan Korybut-Daszkiewicz
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 23 July 2012
Received in revised form 25 October 2012
Accepted 30 October 2012
Available online 8 November 2012
The non-symmetrically functionalized neutral 6,13-substituted-1,4,8,11-tetraazacyclotetradeca-
4,6,11,13-tetraene complexes of copper(II) and nickel(II) were synthesized by mesylation of symmetric
diol derivatives in neat, anhydrous pyridine at 0 °C. The products of monomesylation were used to obtain
macrocyclic copper(II) and nickel(II) complexes substituted with bulky terminal group on one end and
thiol functional group on the other. Linear arrangements of two or three macrocyclic units terminally
blocked with bulky tris(p-tert-butylphenyl)(4-phenoxy)methane substituents were obtained from
monomesylated intermediates. Free ligands obtained by demetallation reaction of neutral copper(II)
tetraazamacrocyclic complexes were used for the synthesis of nickel(II) analogs.
Keywords:
Copper complexes
Nickel complexes
Macrocyclic ligands
Ligand design
Schiff bases
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
element surrounding half of the bismacrocyclic heterodinuclear
cationic complex. Change in redox state of the adjacent metal cen-
The first macrocyclic tetraimine complexes, often referred to as
Jäger macrocycles, were synthesized by template condensation of
bis(b-ketoaldimine)nickel(II) or copper(II) complexes with ethyl-
ene- or 1,3-propylenediamine [1–3]. Jäger cyclization procedure
– with the application of triformylmethane as the starting material
– leads to the formation of complexes substituted only with two
formyl groups in meso positions [4,5]. The carbonyl groups in meso
positions of neutral macrocyclic tetraimine complexes can be O-
methylated transforming them into reactive enol–ether di-cations.
The appended methoxy substituents are readily replaced by amino
residues leading to the formation of the cationic cyclidene com-
ter induced the translocation of the crown to the oxidized one and
now more favorable -acceptor, what was experimentally ob-
served with electroanalytical techniques [8].
p
Neutral Jäger complexes are characterized by higher electron
density than
p-acceptor cationic ones [9], and can be treated as po-
tential -donors. In order to investigate chemical, electrochemical
p
and supramolecular properties of this type of complexes, we have
used tetraimine macrocyclic complexes substituted with ester
groups in meso positions (Scheme 1B). The synthesis of the appropri-
ate 14-membered ligand – 6,13-bis(methoxycarbonyl)-1,4,8,11-
tetraazacyclotetradeca-4,6,11,13-tetraenewasreportedbyTakamura
[10]. The 15- and 16-membered analogs were synthesized following
the template Jäger synthetic strategy [2,3] from 2-formyl-3-
hydroxypropenoic methyl ester and appropriate diamines [11].
Diester complexes are synthetically useful, because it is possible to
carry out a transesterification reactions of the starting methyl esters
with various diols. Reaction with diols introduces two terminal hy-
droxyl groups (e.g., 1Ni and 1Cu shown in Scheme 2) which later can
be transformed in to another functional groups. In particular, we
have shown that dithiol derivatives are suitable for self-assembly
into electroactive monolayers (SAM) on gold surface [12,13]. Chemi-
sorption occurred spontaneously at room temperature, and does not
required any special conditions, while SAMs were electrochemically
stable, and the redox process was reversible. As expected molecules
plexes (Scheme 1A). Bridged with
a,x-diamines, macrobicylic
(lacunar) cyclidene complexes of iron(II) and cobalt(II) were exten-
sively studied by Busch et al. as reversible dioxygen carriers [6].
Macrocyclic tetraimines form stable complexes with nickel(II)
and copper(II) ions and can be reversibly oxidized to 3+ oxidation
state. The double bonds in planar b-diimine 6-membered chelate
rings are delocalized. Therefore, these rings can be recognized
through
p–p donor–acceptor interactions. In our group we have
explored synthesis and properties of dinuclear, bismacrocyclic cyc-
lidenes composed of planar 14-membered dicationic units, and uti-
lized their
rings composed of two joined
p
-acceptor properties [7]. For example tetracationic
-acceptor complex units were used
p
to construct a [2]catenane with a dibenzocrown ether as a p-donor
build into SAMs were able to interact with
ecules in solution, what proves that neutral tetraazamacrocyclic
complexes exhibit -donor character [14].
p-electron deficient mol-
⇑
Corresponding author. Tel.: +48 22 3432035; fax: +48 22 632 66 81.
E-mail address: bkd@icho.edu.pl (B. Korybut-Daszkiewicz).
p
0020-1693/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2012.10.027

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
161
tris(p-tert-butylphenyl)(4-hydroxyphenyl)methane (4) [16] were
obtained according to previously described procedures.
2.2. Measurements
ESI or FD mass spectra were measured with a Mariner Percep-
tive Biosystem and Walters Micromass GCT Premier mass spec-
trometers, respectively. The 1H and 13C NMR spectra were
obtained with Varian Mercury 400, Varian VNMRS 500 and Varian
VNMRS 600 spectrometers. In cases of ambiguous assignment of
observed NMR shifts to appropriate 1H or 13C nuclei, 1H–13C HSQC
correlations spectra were applied. Signals are reported in ppm rel-
ative to the residual solvent signal, d(CHCl3) = 7.26 ppm. In NMR
data descriptions C and H atoms constituting tritylphenol struc-
tural motif are referred as follows: Ca (O–Csp2); Cb and Hb (Csp2–H
in ortho position to ether bond), Cc and Hc (Csp2–H in meta position
to ether bond), Cd (Csp2 in para position to ether bond), Ce (central
quaternary Csp3 atom of the tritylphenol), Cf (Csp2 in para position
to tert-Bu group), Cg and Hg (Csp2–H in meta position to tert-Bu
group), Ch and Hh (Csp2–H in ortho position to tert-Bu group), Ci
(Csp2-tert-Bu group), Cj (quaternary Csp3 atom in tert-Bu), Ck and
Hk (Csp3–H in methyl groups).
Scheme 1.
2.3. Synthesis
12+(PF6
) from 1Cu: 106.1 mg (0.233 mmol) of 1Cu was dis-
2
ꢀ
solved in the mixture of 10 ml MeOH and 5 ml CH2Cl2. Hydrogen
chloride was bubbled through the solution until its color changed
to yellow completely. Solvents were rotary evaporated, and 5 ml of
water was added, to dissolve the salt, followed by addition of
150 mg of NH4PF6 in 0.5 ml of water. Di(hexafluorophosphate) of
protonated ligand 12+ precipitates immediately. This salt was fil-
tered, washed with copious amounts of water, portion of MeOH,
Et2O, and then dried in vacuo. Yield: 144.8 mg (90%). Anal. Calc.
for C18H30F12N4O6P2 (688.4): C, 31.41; H, 4.39; N, 8.14. Found: C,
31.52; H, 4.36; N, 8.20%. ESI MS (MeCN, m/z): 199.1
[C18H30N4O6]2+, 397.2 [C18H29N4O6]+, 543.2 [C18H30N4O6ꢁPF6]+. 1H
NMR (CD3CN, 600 MHz, d (ppm)): 1.99 p (4H, J = 5.3 Hz, CH2CH2-
OH), 3.51 m (4H, axial protons in NCH2CH2N), 3.83
t (4H,
J = 5.1 Hz, CH2OH), 3.91 m (4H, equatorial protons in NCH2CH2N),
4.44 t (4H, J = 5.6 Hz, CH2(CH2)2OH), 7.54 d (4H, J = 15.4 Hz,
CH = N), 10.31 br (4H, NH). 13C NMR (CD3CN, 150 MHz, d (ppm)):
30.2 (CH2CH2OH), 51.1 (NCH2), 61.0 (CH2OH), 65.8 (CH2(CH2)2OH),
95.3 (Csp2C(O)), 165.2 (C = O), 166.0 (CH = N). 1H–15
N HMBC
(CDCl3, 600 MHz) reveals correlations between CH = N nitrogen
(-236.1 ppm), and equatorial protons in NCH2CH2N (3.91 ppm).
1Ni from 12+(PF6ꢀ)2: 95.5 mg of the hexafluorophosphate salt of
12+ (0.139 mmol) was dissolved in 5.0 ml of MeCN. A solution of
41.5 mg of nickel(II) acetate tetrahydrate (1.2 eq) in 4.0 ml of
Scheme 2.
The macrocyclic diol diesters 1Ni and 1Cu (Scheme 2) are
substituted with two chemically identical hydroxyl groups as cen-
ters of further chemical modification. Therefore, the aim of this
work was finding of a method for the efficient monofunctionaliza-
tion at the one of two terminal hydroxyl groups. Such synthetic
step is required if one wants to synthesize derivatives containing
different structural fragments on two opposite ester groups,
including larger molecules containing ‘linearly’ arranged macrocy-
clic units of neutral complexes.
MeOH was added, followed by 79.5 ll of Et3N (4.1 eq). After 2 h
the solution was evaporated to dryness. Orange solid was dissolved
in 2:1vol CH2Cl2:MeOH, and the product separated from the mix-
ture by simple silica gel chromatography with 8% MeOH in CH2Cl2
as an eluent. 1Ni fraction was concentrated, and the product was
precipitated upon addition of Et2O, and dried. Yield: 54.8 mg
(87%). The product is in all respects identical to 1Ni obtained from
previously described standard synthesis.
3Ni: 2.027 g of anhydrous diol 1Ni (4.473 mmol) was dissolved
in 50 ml of dry pyridine upon heating. The solution was chilled to
2. Experimental
0 °C and 276.9 ll of mesyl chloride (0.8 eq) was added slowly to
the stirred clear solution. The reaction was carried out for 45 min
at 0 °C, then allowed to reach room temperature, and left for
30 min. Then, the majority of solvent was vacuum evaporated,
and 40 ml of diethyl ether was added to the oily remnants. The pre-
cipitate was filtered off, rinsed with diethyl ether (3 ꢂ 25 ml), and
dried. Orange solid was suspended in 5 ml of CH2Cl2. This
2.1. Materials
All chemicals and solvents used were obtained from commer-
cial sources and were used as received without further purification.
Macrocyclic complexes 1Ni, 1Cu, 2Ni, 2Cu [12], 11Ni [15] and

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162
suspension was applied to chromatographic column and purified
by dry column vacuum chromatography method, using 60 g of alu-
minum oxide 150 (type T) for TLC as an adsorbent. Gradient elution
starting from 100% CH2Cl2, and ending with 5% MeOH in CH2Cl2 al-
lowed to collect fractions of 2Ni, 3Ni, and 1Ni subsequently. Frac-
tions were concentrated on rotary evaporator, and diluted with
hexane. Precipitates formed immediately, were filtered off, rinsed
with hexane and dried in vacuo. Yield of 2Ni by-product was 9%,
also 30% of 1Ni was recovered. Yield of the main product 3Ni:
1.412 g (56% versus 1Ni, that is 70% versus MsCl). Anal. Calc. for
lected and precipitated by addition of MeOH and evaporation of
CH2Cl2. The precipitate was filtered, washed with MeOH, Et2O
and dried in vacuo. Overall yield: 96.4 mg (69%). Anal. Calc. for
C
92H112N4O6ꢁH2O (1387.9): C, 79.61; H, 8.28; N, 4.04. Found: C, 79.57;
H, 8.25; N, 3.85%. TOF MS FD+ (CH2Cl2, m/z): 1368.7 [C92H112N4O6]+.
1H NMR (CDCl3, 500 MHz, d (ppm)): 1.30 s (54H, Hk), 2.14 p (4H,
J = 6.2 Hz, CH2CH2CH2), 3.55 s (8H, NCH2), 4.05 t (4H, J = 6.2 Hz,
CH2OAr), 4.33
t (4H, J = 6.2 Hz, C(O)OCH2), 6.77 m (4H, Hb),
7.08 m (16H, Hc and Hg), 7.22 m (12H, Hh), 8.27 s (4H, CH@N),
12.57 s (2H, NH). 13C NMR (CDCl3, 125 MHz, d (ppm)): 29.1 (CH2-
CH2CH2), 31.4 (Ck), 34.3 (Cj), 53.5 (NCH2), 60.4 (C(O)OCH2), 63.0
(Ce), 64.6 (CH2OAr), 94.9 (macrocycle Csp2C(O)), 112.9 (Cb), 124.0
(Ch), 130.7 (Cg), 132.2 (Cc), 139.7 (Cd), 144.1 (Cf), 148.3 (Ci), 156.6
(Ca), 157.8 br (CH@N), 168.0 (C@O). NMR signals assignment sup-
ported by 1H–13C HSQC correlation spectra (CDCl3, 500/125 MHz).
5Ni from 5: 62.3 mg of 5 (0.045 mmol) was dissolved in 4 ml of
CH2Cl2. A solution of 13.4 mg of nickel(II) acetate tetrahydrate
C19H28N4NiO8S (531.2): C, 42.96; H, 5.31; N, 10.55. Found: C,
43.00; H, 5.51; N, 10.62%. TOF MS FD+ (CH2Cl2, m/z): 530.1 [C19H28
N4NiO8S]+. 1H NMR (CDCl3, 400 MHz, d (ppm)): 1.88 p (2H,
J = 5.9 Hz, CH2CH2OH), 2.13 p (2H, J = 6.1 Hz, CH2CH2OMs), 3.03 s
(3H, SO2CH3), 3.40 bs (8H, NCH2), 3.66 t (2H, J = 5.8 Hz, CH2OH),
4.29 t (2H, J = 5.8 Hz, CH2OMs), 4.35 t (4H, C(O)OCH2), 7.81 s and
7.82 s (4H, CH = N). 13C NMR (CDCl3, 100 MHz, d (ppm)): 28.9 (CH2-
CH2OMs), 32.6 (CH2CH2OH), 37.6 (SO2CH3), 58.90, 58.95, 59.19,
59.94 and 60.26 (two NCH2, two C(O)OCH2, CH2OH), 67.0 (CH2-
OMs), 98.3 and 98.9 (two macrocycle Csp2C(O)), 154.9 and 155.2
(two CH@N), 169.0 and 169.6 (two C@O).
(1.2 eq) in 1.0 ml MeOH was added, followed by 13.2 ll of Et3N
(2.1 eq). After 2 h the solution was evaporated to dryness. Orange
solid was dissolved in CH2Cl2 and the product was separated chro-
matographically on silica gel column, with 1% MeOH in CH2Cl2 as
an eluent. 5Ni fraction was concentrated, and the product was pre-
cipitated upon addition of MeOH, filtrated, washed with MeOH,
Et2O and dried in vacuo. Yield: 55.4 mg (86%). The product is in
all respects identical to 5Ni obtained from 2Ni as described above.
6Ni: 1.315 g of monomesylate complex 3Ni (2.475 mmol), and
1.250 g tris(p-tertbutylphenyl)(4-hydroxyfenyl)methane (1.0 eq)
were dissolved in 60 ml of anhydrous DMF. 3.230 g of anhydrous
Cs2CO3 (4.0 eq) and about 1.5 g of molecular sieves 3 Å were added.
The resulting mixture was stirred for 3 days at room temperature.
Solids were filtered off, and filtrate was poured into 150 ml of
water. Precipitate, which forms immediately, was filtered off,
washed with water (3 ꢂ 50 ml), and dried. Orange-colored filtrate
was extracted with 2 ꢂ 20 ml of CH2Cl2. The crude product was
dissolved in the organic phase obtained from extraction. The
resulting solution was then washed with 3 ꢂ 200 ml H2O,
1 ꢂ 100 ml of saturated KCl solution, and dried with MgSO4. After
evaporation of the solvent the crude product was purified using
DCVC method (Merck, Silica Gel 60 PF254 for TLC), with 2% MeOH
in CH2Cl2 as an eluent. The first major orange-colored fraction is
collected. The product was precipitated from concentrated solution
with hexane, and dried in vacuo. Yield: 1.489 g (64%). Anal. Calc. for
3Cu: This compound was synthesized from diol 1Cu following
the above procedure for 3Ni. Yield 55% versus 1Cu, that is 69% ver-
sus MsCl. Anal. Calc. for C19H28CuN4O8S H2O (554.1): C, 41.19; H,
5.46; N, 10.11. Found: C, 41.22; H, 5.36; N, 10.20%. TOF MS FD+
(CH2Cl2, m/z): 535.1 [C19H28CuN4O8S]+.
5Ni from 2Ni: 0.462 g of dimesylate complex 2Ni (0.759 mmol),
and
0.803 g
tris(p-tertbutylphenyl)(4-hydroxyfenyl)methane
(2.1 eq) were dissolved in 50 ml of anhydrous DMF. 1.483 g of
anhydrous Cs2CO3 (6.0 eq) and about 1 g of 3 Å MS were added.
The resulting mixture was stirred for 3 days at room temperature.
Solids were filtered off, and filtrate was poured into 150 ml of
water. Immediately formed precipitate was filtered off, washed
with water (3 ꢂ 50 ml) and methanol (25 ml), followed by dissolu-
tion in CH2Cl2, and chromatographic purification (DCVC column
with Silica Gel 60 PF254 TLC-grade, eluted with CH2Cl2). The first or-
ange-colored fraction was collected, and the solvent partially re-
moved by vacuum evaporation. The product 5Ni was precipitated
with methanol, and dried in vacuo. Yield: 0.769 g (71%). Anal. Calc.
for C92H110N4NiO6 (1426.6): C, 77.45; H, 7.77; N, 3.93. Found: C,
77.50; H, 7.82; N, 3.82%. TOF MS FD+ (CH2Cl2, m/z): 1424.8 [C92-
H110N4NiO6]+. 1H NMR (CDCl3, 500 MHz, d (ppm)): 1.30 s (54H,
Hk), 2.14 p (4H, J = 6.3 Hz, CH2CH2CH2), 3.34 s (8H, NCH2), 4.04 t
(4H, J = 6.2 Hz, CH2OAr), 4.33 t (4H, J = 6.1 Hz, C(O)OCH2), 6.77 m
(4H, Hb), 7.07 m (16H, Hc and Hg), 7.23 m (12H, Hh), 7.79 s (4H,
CH@N). 13C NMR (CDCl3, 125 MHz, d (ppm)): 29.2 (CH2CH2CH2),
31.4 (Ck), 34.3 (Cj), 58.7 (NCH2), 60.3 (C(O)OCH2), 63.0 (Ce), 64.6
(CH2OAr), 98.3 (macrocycle Csp2C(O)), 113.0 (Cb), 124.0 (Ch),
130.7 (Cg), 132.2 (Cc), 139.7 (Cd), 144.1 (Cf), 148.3 (Ci), 154.9
(CH@N), 156.6 (Ca), 167.7 (C@O). NMR signals assignment sup-
ported by 1H–13C HSQC correlation spectra (CDCl3, 600/150 MHz).
5Cu: This compound was synthesized from dimesylate 2Cu fol-
lowing the above procedure for 5Ni. Yield 69%. Anal. Calc. for C92
H110CuN4O6 H2O (1449.5): C, 76.24; H, 7.79; N, 3.86. Found: C,
76.14; H, 7.75; N, 3.67%. TOF MS FD+ (CH2Cl2, m/z): 1429.9
[C92H110CuN4O6]+.
C
55H68N4NiO6 (939.9): C, 70.29; H, 7.29; N, 5.96. Found: C, 70.55;
H, 7.23; N, 5.76%. TOF MS FD+ (CH2Cl2, m/z): 938.4 [C55H68N4-
NiO6]+. 1H NMR (CDCl3, 600 MHz, d (ppm)): 1.29 s (27H, Hk), 1.86
p (2H, J = 5.9 Hz, CH2CH2OH), 2.13 p (2H, J = 6,2 Hz, CH2CH2OAr),
3.35 s (8H, NCH2), 3.64 t br (2H, CH2OH), 4.03 t (2H, J = 6.1 Hz,
CH2OAr), 4.32 m (4H, C(O)OCH2), 6.75 m (2H, Hb), 7.06 m (8H, Hc
and Hg), 7.21 m (6H, Hh), 7.78 s (2H, CH@N on the side of bulky
end group), 7.80 s (2H, CH@N on the side of OH end group). 13C
NMR (CDCl3, 150 MHz, d (ppm)): 29.1 (CH2CH2OAr), 31.4 (Ck),
32.5 (CH2CH2OH), 34.3 (Cj), 58.70, 58.77, 58.83 and 59.78
(two NCH2, CH2CH2CH2OH), 60.4 (CH2(CH2)2OAr), 63.0 (Ce), 64.6
(CH2OAr), 98.3 and 98.9 (two Csp2C(O) in macrocycle), 112.9 (Cb),
124.0 (Ch), 130.7 (Cg), 132.3 (Cc), 139.6 (Cd), 144.1 (Cf), 148.3 (Ci),
154.9 br (CH@N), 156.6 (Ca), 167.7 and 168.6 (two C@O).
5: 145.9 mg of 5Cu (0.102 mmol) was dissolved in 20 ml CH2Cl2
and 5 ml MeOH mixture. HCl gas was bubbled through the solution
until the color was changed from pink to yellow and precipitate
has formed. Solvents were evaporated to dryness, and resulting so-
lid was washed in 25 ml of water for 3 h until complete decoloriza-
tion. The chloride salt was then filtrated, and washed with copious
amounts of water. After drying in vacuo the product was added to
6Cu: This compound was synthesized from monomesylate 3Cu
following the above procedure for 6Ni. Yield 61%. Anal. Calc. for
C
55H68CuN4O6 H2O (962.7): C, 68.62; H, 7.33; N, 5.82. Found: C,
68.71; H, 7.33; N, 5.80%. TOF MS FD+ (CH2Cl2, m/z): 943.3
[C55H68CuN4O6]+.
7Ni: The solution of 1.315 g of alcohol 6Ni (1.400 mmol) in
150 ml of dry CH2Cl2 was cooled to 0 °C. Two-hundred and
the solution of 29.1
ll of triethylamine (2.05 eq) in 3 ml of CH2Cl2.
thirty-five microliters of triethylamine (1.2 eq) and 120 ll of mesyl
The solution of neutralized ligand 5 was then poured on short silica
chloride (1.1 eq) were added. The reaction was carried out at 0 °C
gel column and eluted with CH2Cl2. First colorless fraction was col-
for 2 h, than allowed to reach room temperature. The solvent

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
163
was rotary evaporated, remnants dissolved in small volume of CH2-
Cl2 and purified chromatographically on neutral alumina column
with 0.5% MeOH in CH2Cl2 as an eluent. The main fraction was con-
centrated, and product precipitated upon addition of methanol.
Monomesylate 7Ni was then filtered and dried in vacuo. Yield:
1.257 g (88%). Anal. Calc. for C56H70N4NiO8S H2O (1036.0): C,
64.93; H, 7.00; N, 5.41. Found: C, 65.00; H, 7.12; N, 5.39%. TOF
MS FD+ (CH2Cl2, m/z): 1016.4 [C56H70N4NiO8S]+. 1H NMR (CDCl3,
400 MHz, d (ppm)): 1.30 s (27H, Hk), 2.13 m (4H, CH2CH2CH2),
3.01 s (3H, SO2CH3), 3.35 bs (8H, NCH2), 4.04 t (2H, J = 6.2 Hz, CH2-
OAr), 4.29 t (2H, J = 6.0 Hz, CH2OMs), 4.34 m (4H, C(O)OCH2),
6.76 m (2H, Hb), 7.07 m (8H, Hc and Hg), 7.23 m (6H, Hh), 7.79 bs
(4H, CH = N). 13C NMR (CDCl3, 100 MHz, d (ppm)): 28.9 (CH2CH2-
OMs), 29.2 (CH2CH2OAr), 31.5 (Ck), 35.7 (Cj), 37.6 (SO2CH3), 58.8,
58.9, 60.4 (two NCH2, CH2(CH2)2OAr), 63.1 (Ce), 64.6 (CH2OAr),
67.0 (CH2OMs), 98.3 br (two Csp2C(O) in macrocycle), 113.0 (Cb),
124.1 (Ch), 130.8 (Cg), 132.3 (Cc), 139.7 (Cd), 144.2 (Cf), 148.4 (Ci),
155.1 br (two CH = N), 156.7 (Ca), 167.79 and 167.82
(two C = O).
it clarified and no gas formation was longer observed. The solution
was evaporated to dryness and kept in vacuum for another 0.5 h to
remove remnants of (COCl)2. The solution of 0.726 g of alcohol 6Ni
(0.3 eq) and 0.538 ml of anhydrous Et3N (1.5 eq) in 10 ml of dry
CH2Cl2 containing about 0.5 g of molecular sieves 3 Å, was pre-
pared and cooled to 0 °C. Already obtained pale-yellow oil of
3,30-dithiodipropionic acid dichloride was dissolved in 5 ml of
dry CH2Cl2 and added dropwise during 3 h to the solution of 6Ni.
The reaction mixture was then stirred for another 0.5 h and 3 ml
of MeOH were added. After 15 min molecular sieves were filtered
off, and the solution was evaporated to dryness. The crude mixture
was dissolved in CH2Cl2 and purified chromatographically (TLC-
grade Silica Gel 60 PF254; CH2Cl2 followed by 1% MeOH in CH2Cl2
as eluents). Second, major orange-colored fraction was collected
and concentrated. The product was precipitated upon addition of
methanol, filtered off, dissolved in CH2Cl2 once more and precipi-
tated upon addition of hexane, filtered and dried in vacuo. Yield:
0.499 g (56%). Anal. Calc. for C116H142N8Ni2O14S2 H2O (2072.0): C,
67.24; H, 7.00; N, 5.41. Found: C, 67.23; H, 6.97; N, 5.46%. TOF
MS FD+ (CH2Cl2, m/z): 2050.9 [C116H142N8Ni2O14S2]+. 1H NMR
7Cu: This compound was synthesized from 6Cu following the
procedure described for 7Ni. Yield 81%. Anal. Calc. for C56H70CuN4-
O8S H2O (1039.4): C, 64.62; H, 6.97; N, 5.38. Found: C, 64.51; H,
7.03; N, 5.39%. TOF MS FD+ (CH2Cl2, m/z): 1021.4 [C56H70N4NiO8S]+.
8Ni: The monomesylate 7Ni (1.100 g, 1.081 mmol) and thiourea
(0.411 g, 5 eq) were dissolved in 150 ml of DMF. The reaction was
carried out at 50 °C for 24 h, after which no substrate was observed
on TLC plates. DMF was partially removed on rotary evaporator
and 300 ml of water was added to the solution. The immediately
formed precipitate of isothiouronium salt was filtered, washed
with 3 ꢂ 50 ml H2O, 50 ml MeOH, and suspended in 300 ml of cold
water, without further purification. A solution of 15 g NaOH in
50 ml H2O was then added dropwise, and the resulting mixture
was stirred under inert atmosphere for 5 h. The mixture was
cooled in the fridge, and about 32 ml of hydrochloric acid was
added dropwise, until neutral pH was reached. The precipitate
was filtered off, washed with copious amounts of water, followed
by a portion of MeOH, and dried in vacuo. The crude product thus
obtained was dissolved in CH2Cl2 and purified chromatographically
(TLC-grade Silica Gel 60 PF254; 1% MeOH in CH2Cl2 as an eluent).
The first main orange-colored fraction was collected, and the sol-
vent partially removed by vacuum evaporation. The product pre-
cipitated upon addition of Et2O was filtered and dried in vacuo.
Yield: 0.494 g (47.8%). Anal. Calc. for C55H68N4NiO5S H2O (973.9):
C, 67.83; H, 7.24; N, 5.75. Found: C, 67.91; H, 7.29; N, 5.66%. TOF
MS FD+ (CH2Cl2, m/z): 954.4 [C55H68N4NiO5S]+. 1H NMR (CDCl3,
400 MHz, d (ppm)): 1.30 s (27H, Hk), 2.07 p (2H, J = 6.8 Hz, CH2CH2-
SH), 2.14 p (2H, J = 6.2 Hz, CH2CH2OAr), 2.77 t (2H, J = 7.2 Hz, CH2-
SH), 3.36 s (8H, NCH2), 4.04 t (2H, J = 6.2 Hz, CH2OAr), 4.25 t (2H,
J = 6.2 Hz, CH2(CH2)2SH), 4.33 t (2H, J = 6.2 Hz, CH2(CH2)2OAr),
6.76 m (2H, Hb), 7.08 m (8H, Hc and Hg), 7.23 m (6H, Hh), 7.79 s
br (4H, two CH@N). 13C NMR (CDCl3, 100 MHz, d (ppm)): 29.0 (CH2-
CH2SH), 29.3 (CH2CH2OAr), 31.5 (Ck), 34.4 (Cj), 35.68 and 35.71
(two CH2CH2CH2), 58.87, 58.91, 61.011, 60.499 and 61.844 (two
NCH2, two C(O)OCH2, CH2SH), 63.2 (Ce), 64.7 (CH2OAr), 98.3 and
98.4 (two Csp2C(O) in macrocycle), 113.1 (Cb), 124.2 (Ch), 130.8
(Cg), 132.4 (Cc), 139.8 (Cd), 144.3 (Cf), 148.4 (Ci), 155.0 br (CH@N),
156.8 (Ca), 167.78 and 167.84 (two C@O).
(CDCl3, 500 MHz,
d (ppm)): 1.30 s (54H, Hk), 2.02 p (4H,
J = 6.3 Hz, CH2CH2OC(O)(CH2)2S), 2.14 p (4H, J = 6.2 Hz, CH2CH2-
OAr), 2.74 t (4H, J = 7.2 Hz, C(O)CH2), 2.93 t (4H, J = 7.1 Hz, SCH2),
3.36 s br (16H, NCH2), 4.04 t (4H, J = 6.2 Hz, CH2OAr), 4.21 t (4H,
J = 6.4 Hz, CH2OC(O)(CH2)2S), 4.23
t
(4H, J = 6.3 Hz, Csp2–
C(O)OCH2(CH2)2OC(O)), 4.33 t (4H, J = 6.2 Hz, C(O)OCH2(CH2)2OAr),
6.76 m (4H, Hb), 7.07 m (16H, Hc and Hg), 7.23 m (12H, Hh), 7.79 s
br (8H, CH = N). 13C NMR (CDCl3, 125 MHz, d (ppm)): 28.4 (CH2CH2-
OC(O)CH2), 29.2 (CH2CH2OAr), 31.4 (Ck), 33.1 (SCH2), 34.1
(C(O)CH2), 34.3 (Cj), 58.7 and 58.8 (NCH2), 59.8 (CH2(CH2)2-
OC(O)CH2), 60.3 (CH2(CH2)2OAr), 61.8 (CH2OC(O)CH2), 63.0 (Ce),
64.6 (CH2OAr), 98.1 and 98.3 (two Csp2C(O) in macrocycle), 112.9
(Cb), 124.0 (Ch), 130.7 (Cg), 132.2 (Cc), 139.6 (Cd), 144.1 (Cf), 148.3
(Ci), 154.9 br (CH = N), 156.6 (Ca), 167.6 and 167.7 (two Csp2C = O
at macrocycle), 171.6 (C(O)CH2). The NMR signals assignment
was supported by 1H–13C HSQC correlation spectra (CDCl3, 600/
150 MHz).
9Cu2: This compound was synthesized from 6Cu following the
procedure described for 9Ni2. Yield 49%. Anal. Calc. for C116H142-
Cu2N8O14S2 2H2O (2099.7): C, 66.36; H, 7.01; N, 5.34. Found: C,
66.40; H, 7.00; N, 5.08%. TOF MS FD+ (CH2Cl2, m/z): 2060.5
[C116H142Cu2N8O14S2]+.
10Ni: Complex 3Ni (396 mg, 0.746 mmol) was dissolved in
20 ml CH2Cl2. A solution of sodium azide (1.212 g, 25 eq) and tet-
rabutylammonium bromide (0.241 g, 1 eq) in 6 ml H2O was
added. This two phase system was degassed and stirred vigor-
ously under argon atmosphere for 4 days. The organic phase
was then washed with 50 ml H2O, dried over MgSO4, and con-
centrated. The residue was dissolved in methanol (10 ml) and
the mixture left for crystallization upon evaporation of solvents.
Crystals of the product were filtered, washed with Et2O and dried
in vacuo. Yield: 334.6 mg (94%). Anal. Calc. for C18H25N7NiO5
(478.1): C, 45.22; H, 5.27; N, 20.51. Found: C, 45.29; H, 5.26; N,
20.35%. TOF MS FD+ (CH2Cl2, m/z): 477.1 [C18H25N7NiO5]+. 1H
NMR (CDCl3, 500 MHz, d (ppm)): 1.88 t (2H, J = 6.0 Hz, CH2CH2-
OH), 1.96 t (2H, J = 6.5 Hz, CH2CH2N3), 2.52 t (1H, J = 6.2 Hz,
OH), 3.39 s (8H, NCH2CH2N), 3.41 t (2H, J = 6.5 Hz, CH2N3), 3.66
q (2H, J = 5.9 Hz, CH2OH), 4.25 t (2H, J = 6.2 Hz, CH2(CH2)2N3),
4.34 t (2H, J = 6.0 Hz, CH2(CH2)2OH), 7.81 s and 7.82 s (2 ꢂ 2H,
CH = N). 13C NMR (CDCl3, 125 MHz, d (ppm)): 28.6 (CH2CH2N3);
32.5 (CH2CH2OH); 48.5 (CH2N3); 58.7, 58.8, 58.9, 59.8 and 60.3
(two C(O)OCH2, two NCH2, CH2OH); 98.0 and 98.1 (two Csp2C(O)
in macrocycle); 154.9 and 155.0 (two CH@N); 167.5 and 168.5
(two C@O).
8Cu: this compound was synthesized from 7Cu following the
procedure described above for 8Ni. Yield 37%. Anal. Calc. for
C
55H68CuN4O5S H2O (978.8): C, 67.49; H, 7.21; N, 5.72. Found: C,
67.55; H, 7.30; N, 5.61%. TOF MS FD+ (CH2Cl2, m/z): 959.4
[C55H68CuN4O5S]+.
9Ni2: 0.541 g of 3,30-dithiodipropionic acid (2.575 mmol) was
suspended in 5 ml of freshly distilled, anhydrous CH2Cl2. A drop
of dry DMF was added, followed by 0.66 ml of oxalyl chloride
(3 eq). The mixture was left for 1.5 h under inert atmosphere until
10Cu complex was also obtained following the procedure for
10Ni. Yield 87%. Anal. Calc. for C, 44.76; H, 5.22; N, 20.30. Found:

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
164
C, 44.62; H, 5.12; N, 20.12%. TOF MS FD+ (CH2Cl2, m/z): 482.1
[C18H25CuN7O5]+.
3.2. Synthesis of linear complexes
Intercalation of -acceptors into the monolayer of simple
dithiol counterparts of 1Ni and 1Cu is relatively limited due to
the well-packed structure of the SAM film. Here, we present our re-
cent advances in chemical synthesis of new derivatives of neutral
tetraazamacrocyclic complexes of copper(II) and nickel(II), aimed
at designing molecules potentially capable of formation of SAMs
12Ni3: 237.1 mg of 10Ni (0.496 mmol), 118.6 mg of 11Ni
(0.5 eq), and 305.3 mg (benzyltriazolyl)methylamine (1 eq) were
dissolved in the mixture of 9.5 ml CH2Cl2 and 4.75 ml MeOH.
349.1 mg of copper(I) iodide (3.2 eq) was added, and the mixture
was stirred under argon in room temperature. After 2 days, addi-
tional portion of CuI (109 mg, 1 eq) was added, and the reaction
was carried out for yet another 2 days. Than 20 ml CH2Cl2 and
10 ml MeOH were added to the suspension, solids were filtrated,
and the filtrate was evaporated to dryness. The remaining brown
solid was dissolved in small amount of CH2Cl2 containing 2% of
MeOH, followed by purification on silica gel DCVC column. Gradi-
ent elution from 2% to 10% of MeOH in CH2Cl2 was used, and the
product 12Ni3 was collected as the fourth colored fraction. After
partial evaporation of the solvent the product was precipitated
with hexane, filtered, and dried in vacuo. Yield: 41.1 mg (12%).
Anal. Calc. for C56H72N18Ni3O14 (1397.4): C, 48.13; H, 5.19; N,
18.04. Found: C, 48.20; H, 5.22; N, 17.98%. TOF MS FD+ (CH2Cl2,
p
with inherent free spaces built between units of
p-donor com-
plexes. That would facilitate intercalation of -electron deficient
p
molecules into the SAM film. We have also investigated the synthe-
sis of compounds containing two or three units of electron rich tet-
raazamacrocyclic complex linearly arranged within one molecule,
for future studies in their ability to participate in intermolecular
interactions, when influenced by the increased number of
units.
p-donor
For introduction of bulky end groups to complex molecules we
have chosen tris(p-tert-butylphenyl)(4-hydroxyphenyl)methane
(4). This compound was obtained following a known two-step syn-
thesis [16]. Reactions of 4 with dimesylates 2M were carried out in
presence of a cesium carbonate in anhydrous DMF (Scheme 3).
Neutral complex derivatives containing two bulky end groups
were obtained with 69% yield for 5Cu and 71% for 5Ni. The reac-
tions were carried out for 3 days at room temperature, since ele-
vated temperatures led to decrease of the yield, due to partial
degradation of dimesylates. The analogous reaction of 2Ni with
commercially available tritylphenol was also tested, and it pro-
ceeded with a similar yield. However, the product substituted with
large number of aromatic rings, and containing no aliphatic sub-
stituents was sparingly soluble in all common solvents.
The monomesylates 3M have been also used to synthesize
monothiols 8M. Complex 3M was at first reacted with tris(p-
tert-butylphenyl)(4-hydroxyphenyl)methane, then the remaining
hydroxyl group mesylation was followed by substitution towards
isothiouronium salt, alkaline hydrolysis of the salt, and protonation
of the resulting thiolate (Scheme 4).
m/z): 1394.3 [C56H72N18Ni3O14]+, 1417.3 [C56H72N18Ni3O14ꢁNa]+,
2+
697.2 [C56H72N18Ni3O14
]
,
720.2 [C56H72N18Ni3O14ꢁ2Na]2+
.
1H
NMR (CDCl3, 600 MHz, d (ppm)): 1.86 p (4H, J = 6.0 Hz, CH2CH2OH),
2.26 p (4H, J = 6.3 Hz, CH2CH2CH2N), 3.11 t br (4H, CH2Csp2), 3.35 s
(16H, N(CH2)2N in terminal complex units), 3.38 (8H, N(CH2)2N in
central complex unit), 3.65 t (4H, J = 5.7 Hz, CH2OH), 4.19 t (4H,
J = 5.7 Hz, CH2(CH2)2N), 4.32 t (4H, J = 6.0 Hz, CH2(CH2)2OH), 4.40
t (4H, J = 6.6 Hz, CH2CH2Csp2), 4.42 t (4H, J = 7.8 Hz, (CH2)2CH2N),
7.41 s br (2H, triazole proton), 7.72 s (4H, CH = N in central com-
plex unit), 7.75 s and 7.79 s (8H, CH = N in terminal complex units).
13C NMR (CDCl3, 150 MHz, d (ppm)): 25.9 (CH2Csp2), 29.9 (CH2CH2-
CH2N), 32.4 (CH2CH2OH), 47.7 ((CH2)2CH2N), 58.75, 58.77 and
58.83 (N(CH2)N and (CH2)2CH2OH), 59.87 and 59.92 (CH2(CH2)2OH
and CH2(CH2)2N), 62.0 (CH2CH2Csp2), 97.8, 98.0, and 98.1 (three dif-
ferent Csp2C(O) in macrocycles), 121.8 (triazole CH), 145.5 (CH2-
Csp2), 154.9 and 155.0 (CH@N in macrocycles), 167.5, 167.6, and
168.5 (three C@O).
3. Results and discussion
3.1. Synthetic route towards non-symmetrical complexes of Cu(II) and
Ni(II)
The synthetic route towards non-symmetrically functionalized
tetraazamacrocyclic complexes was found by studying mesylation
of diols 1M (Scheme 2). Typical mesylation of 1M in dichlorometh-
ane, carried out with 0.8–1.0 equivalent of mesyl chloride, leads
preferentially to undesired symmetrical derivatives – dimesylates
2M, suggesting that monomesylate intermediate (3M) is more
reactive towards mesyl chloride, than the substrate 1M. Yields of
monomesylates 3M were unsatisfactory – between 20% and 25%,
what is even two times lower than what one might expect from
purely statistical distribution. The ratio of products was nearly
independent from the rate of mesyl chloride addition, and did
not improved even when the reactant was slowly added with the
help of syringe pump. Our experiments show that the well-known
Ag2O-aided method for monotosylation of symmetrical diols [17],
did not improved the yields either. Dimesylated or ditosylated
products were formed preferentially, showing that Ag2O had no
influence on the chemical behavior of diols 1M. However, when
the mesylation of 1M is carried out with 0.8 eq of mesyl chloride
in neat, anhydrous pyridine at 0 °C, desired monomesylates 3Cu
and 3Ni are formed with decent yields (Scheme 2) – conversion
of MsCl to 3M is about 70%. That result is better than 1:2:1 distri-
bution of diol to monomesylate to dimesylate, expected if only
statistical factors would play role during reaction course.
Scheme 3.

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
165
Scheme 4.
Additionally, alcohols 6M, intermediate products in this series of
reactions, were used as substrates in the synthesis of dinuclear
complexes 9Cu2 and 9Ni2 (Scheme 5). These compounds were syn-
thesized by coupling two molecules of 6M with freshly generated
3,30-dithiodipropionic acid dichloride, providing homodinuclear
complexes with a linker containing a disulfide bond. Both 9Cu2
and 9Ni2 were synthesized with decent yields (49% and 56%, respec-
tively). Unfortunately, synthesis of heterodinuclear complex 9CuNi
couldn’t be realized by similar reaction of acid dichloride with an
equimolar mixture of 6Ni and 6Cu, since separation of compounds
from statistical mixture of 9Ni2, 9Cu2 and 9CuNi was not successful.
Disulfides are useful in self-assembly of monolayers, since they
anchor to the gold surface. It is worthwhile mentioning that linear
molecules 9M2, as well as compounds 5M can be used in future
for exploiting their p-donor properties in solutions and solid state,
as well as they may function as potential rotaxane axels interacting
with macrocycles containing electron deficient moieties.
In order to further develop linear arrangement of macrocylic me-
tal complex units we have used 1,3-dipolar Huisgen cycloaddition.
The monomesylate 3Ni was transformed by standard procedure
into monoazide 10Ni, which has been then used in cycloaddition
reaction with diacetylene derivative 11Ni (Scheme 6). This reaction
was cactalyzed by tris(benzyltriazolyl)methylamine (TBTA), which
prevents oxidation and disproportionation of copper(I) [18]. Linear
Scheme 5.
Scheme 6.

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
166
product 12Ni3, containing three neutral complex units was isolated
with 12% yield.
3.3. Demetallation of copper complexes
In highly acidic conditions copper(II) complexes are prone to
demetallation, which does not occur in case of nickel(II) complexes
under the same conditions. The demetallation reaction is carried
out by bubbling HCl gas through the solution of a copper complex
in the mixture of dichloromethane with methanol. After few min-
utes of bubbling characteristic pink color changes into yellow,
coming from the tetrachlorocopper(II) dianion. Protonated dicat-
ionic ligand is produced simultaneously. In case of 1Cu complex
with polar terminal groups, this chloride was soluble in water, thus
1
2+ ligand was precipitated as hexafluorophosphate salt upon addi-
tion of NH4PF6 (Scheme 7).
In case, when the terminal groups of the complex are non-polar,
like bulky groups in 5Cu, the yellow precipitate of CuCl4 salt is
Scheme 7.
2ꢀ
formed during HCl gas bubbling. This precipitate quickly trans-
forms into dichloride when stirred in water. However, since dichlo-
ride of 52+ ligand was poorly soluble in any common solvent it was
separated as neutral ligand 5 upon neutralization with two equiv-
alents of triethylamine and filtration through short silica gel
column (Scheme 8).
Since demetallation reaction is reversible, it is possible to
regenerate copper(II) or nickel(II) complex from the ligand ob-
tained. Indeed, we have succeeded in the synthesis of 1Ni complex
starting from 1Cu, and going through 12+(PF6
) salt with 78%
2
ꢀ
overall yield, as well as in demetallation of 5Cu complex to neutral
ligand 5, followed by recomplexation with Ni2+ ions to form 5Ni
complex with 59% overall yield. Therefore the demetallation reac-
tion of copper(II) tetraazamacrocyclic complexes and its universal
character provide a shortcut that allows obtaining nickel(II) com-
plexes from their copper(II) counterparts, instead of repetition of
the whole reaction sequences for nickel(II) starting materials.
The structures of synthesized complexes and free ligands were
established in terms of elemental analyses, reactions and spectral
evidence. The diamagnetic nickel(II) complexes and demetallated
ligands were characterized by 1H and 13C NMR spectra, and the sig-
nals assignment was supported by 2D 1H–13C correlation spectra.
All studied compound were also identified by electrospray (ESI)
or field desorption (FD) mass spectra, especially useful in the case
of copper(II) complexes. Since, due to paramagnetic properties of
Scheme 8.
Fig. 1. Experimental (above) and calculated (below) isotopic profiles of [M]+ peaks in FD mass spectra of mono-, di- and tri-nuclear nickel complexes 5Ni, 9Ni2, 12Ni3.

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
167
of nickel(II) complexes and neutral ligand 5, signals of protons of
ethylenediamine bridges appear as two separate multiplets at
3.51 and 3.91 ppm. The values of coupling constants have been
determined, and the shape of these multiplets simulated by itera-
tive fitting to experimental spectrum using a homemade software
(Fig. 2).
Protons in NCH2CH2N bridge are coupled geminally with a cal-
2
culated constant JH,H = ꢀ14.43 Hz. Vicinal coupling constants are
3JH,H = 2.04, 2.35 Hz for protons in gauche, and 10.97 Hz for protons
in anti positions. Protons of methylene groups are also coupled to
3
NH protons with JH,H = 3.94 and 8.44 Hz. All coupling constants
and chemical shifts are summarized in Fig. 3B.
3
Obtained JH,H values were used to determine the geometry of
3
ethylenediamine bridges, using ‘Generalized JH,H calculation
according to Haasnoot et al.’ script [19,20]. Calculated values of
dihedral angles in NCH2CH2N bridge are equal to 57°, 71° and
162° (Fig. 3A). The protonated macrocyclic ring in 12+ cation con-
formation consistent with these values is shown in Fig. 3B. Similar
conformation was previously established for the methyl ester ana-
log of 12+ by X-ray crystallography [10]. The unsaturated, planar
parts of the macrocycle adopt s-trans conformations with all NH
protons pointing on the outside of a ring, whereas in the free ligand
the remaining two protons form strong hydrogen bonds between
nitrogen atoms and are located inside of the macrocyclic ring [10].
4. Conclusions
Fig. 2. Simulated (above) and experimental (below) shapes of signals of axial (Ha)
and equatorial (He) protons in ethylenediamine bridge in 1H NMR spectra of diol
12+ (CD3CN, 600 MHz, 25 °C).
The synthetic route towards non-symmetrically functionalized
tetraazamacrocyclic complexes was found by mesylation of sym-
metric diols 1M in neat, anhydrous pyridine at 0 °C. Selective
monomesylation allowed unsymmetrical elaboration of macrocylic
ligand superstructure. This synthetic strategy was used to obtain
macrocyclic copper(II) and nickel(II) complexes substituted with
bulky terminal group on one side and thiol functional group on
the other. Linear arrangements of two or three macrocyclic units
terminally blocked with bulky tris(p-tert-butylphenyl)(4-phen-
oxy)methane substituents were obtained from selectively monom-
esylated intermediates. It is our intention to use such linear
molecules as rotaxane axels interacting with macrocycles contain-
ing electron deficient moieties.
these complexes the NMR data were not available. In all instances,
m/z values as well as the isotopic profiles of mass peaks were con-
sistent with calculated ones, as is shown for mono-, di- and tri-nu-
clear nickel(II) complexes 5Ni, 9Ni2, 12Ni3 in Fig. 1.
As expected, in neutral ligand 5 tautomeric exchange of NH pro-
tons between nitrogen atoms was a fast process compared to the
NMR time scale, resulting in averaged signals both for 1H, and
13C nuclei in imine/enamine groups and ethylenediamine bridges
at 25 °C. On the other hand, in protonated molecule 12+ dynamical
exchange of protons between nitrogen atoms does not occur.
Therefore the signal of imine protons CH@N is observed as a dou-
The demetallation reaction of neutral copper(II) tetraazamacro-
cyclic complexes provide a shortcut that allows obtaining com-
plexes with another transition metal ions from their copper(II)
counterparts.
3
blet with a coupling constant to NH protons, JH,H = 15.41 Hz.
Moreover, in contrast to what was observed in 1H NMR spectra
Fig. 3. Torsion angles in ethylenediamine bridge as seen with Newman projection (A), and schematic structure of 12+ cation, with chemical shifts of protons in macrocycle,
and all coupling constants between them (B).

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M. Wozny et al. / Inorganica Chimica Acta 395 (2013) 160–168
[8] B. Korybut-Daszkiewicz, A. Wie˛ckowska, R. Bilewicz, S. Domagała, K. Woz´niak,
Acknowledgements
Angew. Chem., Int. Ed. 43 (2004) 1668;
B. Korybut-Daszkiewicz, A. Wie˛ckowska, R. Bilewicz, S. Domagała, K. Woz´niak,
Angew. Chem. 116 (2004) 1700–1704.
[9] S. Domagała, B. Korybut-Daszkiewicz, L. Straver, K. Woz´niak, Inorg. Chem. 48
(2009) 4010.
[10] S. Takamura, T. Yoshimiya, S. Kameyama, A. Nishida, H. Yamamoto, M.
Noguchi, Synthesis 5 (2000) 637.
The authors are grateful to the National Science Center in Po-
land for financial support of this work Grant N N204 151640, and
NSC Preludium Grant 2011/01/N/ST5/05560. The authors thank
Prof. S. Szyman´ ski (Institute of Organic Chemistry, Polish Academy
of Science, Warsaw, Poland) for helpful discussion about the NMR
results.
´
´
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Wie˛ckowska, R. Bilewicz, B. Korybut-Daszkiewicz, Eur. J. Inorg. Chem. (2007)
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