50
C. Cretu et al. / Polyhedron 85 (2015) 48–59
Table 1
Crystal data and structure refinement parameters for H2L (1), [Co(L)]3(ClO4).34H2O (2) and [Zn2(L)(CH3COO)2] (3).
1
2
3
Empirical formula
C
24H32N4O2
C72H98Cl3Co3N12O22
1766.79
monoclinic
295
C28H36N4O6Zn2
655.38
monoclinic
295
Formula weight
Crystal system
T (K)
408.54
monoclinic
295
Space group
a (Å)
b (Å)
P21/c (no. 14)
21.9135(13)
5.8162(3)
8.9060(5)
92.031(4)
1134.4(1)
2
C2/c (no. 15)
30.535(12)
17.535(6)
19.449(15)
123.747(7)
8659(8)
4
1.36
0.735
P21/c (no. 14)
12.434(5)
17.968(6)
12.739(4)
95.112(9)
2834.8(17)
4
1.74
c (Å)
b (°)
V (Å3)
Z
Dcalc (Mg mꢀ3
)
1.20
0.077
Absorption coefficient
l
(mmꢀ1
)
1.741
Range of h, k, l
ꢀ32 ? 35, 0 ? 9, ꢀ14 ? 34
ꢀ39 ? 38, 0 ? 22, ꢀ24 ? 24
ꢀ17 ? 17, ꢀ25 ? 25, ꢀ13 ? 18
Goodness-of-fit (GOF) on F2
0.979
0.986
1.036
No. of reflections useda/parameters refined
R
Rw
3158/136
0.042b
5735/497
0.051b
3818/361
0.046b
0.119b
0.055b
0.116b
Chebychev series in ti(x), and x = F2calc/Fc2alc
,
max
ꢀ1
w = w0 ꢁ [1 ꢀ (
D
Fobs/6 ꢁ
D
Fest)2]2 where w0 = [P0T00(x) + P1T10(x) + . . .Pnꢀ1Tnꢀ1 (x)]
and Pi are the coefficients of
a
0
w = (1/4F2obs) ꢁ 1.
a
Reflections with I > 2
r(I).
b
R values are based on F values, Rw values are based on F2.
6.74 Hz); 6.86 (t, 1H, ArH, J = 7.89, 7.89 Hz); 6.95 (d, 1H, ArH,
J = 8.30 Hz); 7.30 (dd, 1H, ArH, J = 9.07, 8.12 Hz); 7.23 (d, 1H, ArH,
J = 9.09 Hz,); 8.34 (s, 1H, HC@N); 13.55 (s, 1H, OH). 13C NMR
(400 MHz), CDCl3/d [ppm]: 27.93 (C9), 53.20 (C10), 55.87
(C11,12), 57.47 (C8), 117.01 (C2), 118.42 (C4), 118.77 (C6),
131.10 (C5), 132.66 (C3), 161.30 (C7), 164.96 (C1). FT-IR [KBr,
cmꢀ1]: 3481 (br, w), 3061 (w), 3003 (w), 2946 (w), 2880 (m),
2810 (m), 2776 (m), 1631 (s), 1578 (m), 1494 (m), 1456 (m),
1412 (m), 1345 (m), 1314 (m), 1278 (m), 1203 (m), 1150 (m),
1022 (m), 978 (w), 960 (w), 846 (m), 751 (m), 652 (w), 465 (w).
(400 MHz), CDCl3, DMSO-d6/d [ppm]: 2.02 (m, 5H, CH2, CH3acetate);
2.78 (m, 2H, exoCH2N); 3.14 (m, 4H, N(CH2CH2)pip); 3.88 (t, 2H, CH2);
6.54–6.56 (d, 1H, ArH, J = 7.17); 6.82–6.86 (d, 1H, ArH, J = 8.50 Hz);
7.05–7.07 (d, 1H, ArH, J = 7.74 Hz); 7.21–7.24 (d, 1H, ArH,
J = 7.68 Hz); 8.11 (s, 1H, HC@N). 13C NMR (400 MHz), CDCl3,
DMSO-d6/d [ppm]: 21.54 (C26); 26.60 (C9), 52.54 (C10), 59.76
(C8,11,13), 117.93 (C2,4,6), 134.60 (C5), 135.26 (C3), 168.98 (C7),
169.97 (C1), 179.26 (C25). FT-IR [KBr, cmꢀ1]: 3017 (w), 2907 (m),
2860 (m), 1641 (vs), 1601 (s), 1572 (s), 1539 (s), 1447 (vs), 1450
(vs), 1398 (s), 1336 (s), 1315 (s), 1282 (m), 1210 (w), 1188 (m),
1140 (m), 1129 (m), 1087 (m), 1054 (m), 1032 (m), 974 (w), 958
(m), 926 (w), 910 (w), 883 (w), 850 (w), 804 (w), 781 (w), 755
(m), 736 (w), 683 (m), 642 (w), 601 (m), 562 (w), 458 (m), 412
e
UV–Vis (CHCl3 7ꢂ10-4M) kmax [nm] ( /L molꢀ1 cmꢀ1): 274(1000),
316(3500), 409(171). Fluorescence (CHCl3, 20 °C, 10ꢀ5 M): kex
350 nm; kem 450 nm.
(w). Molar conductivity KM, X
ꢀ1 molꢀ1 cm2 (CHCl3, 10ꢀ3 M): 0.
UV–Vis (CHCl3, 10ꢀ3 M) kmax [nm]: 280(1860), 367(2830),
387(1270). Fluorescence (CHCl3, 20 °C, 10ꢀ5 M): kex 368 nm; kem
446 nm.
2.3.2. [Co(L)]3(ClO4).34H2O (2)
H2L (0.50 g, 1.2 mmol) in CHCl3-MeOH (1:1 v/v, 20 ml) was
treated with Et3N (0.51 ml, 3.7 mmol) and Co(ClO4)2ꢂ6H2O
(0.89 g, 2.4 mmol) dissolved in MeOH (10 ml). The mixture was
stirred for 1 h at room temperature and the derived green–brown
solid was isolated, washed with methanol, and dried in air, afford-
ing a crystalline product. Yield 0.68 g (98%). Brown single crystals
suitable for X-ray analysis were obtained by slow evaporation of
the mother liquor CHCl3-MeOH 1:1 (v/v). Anal. Calc. for C72H98Cl3-
Co3N12O22 (1766.79): C, 48.95; H, 5.59; N, 9.51; Cl, 6.02; Co, 10.01.
Found: C, 48.83; H, 5.61; N, 9.47; Cl, 6.09; Co, 10.11%. FT-IR [KBr,
cmꢀ1]: 3445 (br, w), 3042 (w), 3015 (w), 2938 (w), 2902 (w),
2878 (w), 1623 (vs), 1595 (s), 1541 (m), 1471 (m), 1455 (s), 1404
(w), 1365 (w), 1337 (m), 1311 (s), 1254 (w), 1236 (w), 1213 (w),
1169 (w), 1153 (w), 1093 (vs), 970 (m), 903 (w), 847 (w), 767
(m), 738 (w), 622 (m), 595 (w), 567 (w), 497 (w), 468 (w), 441
3. Results
3.1. Synthesis
The synthesis of both the organic ligand and the associated
binary-ternary metal compounds was pursued through efficient
reactions. Specifically, the ligand N,N0-bis[(2-hydroxybenzilidenea-
mino)-propyl]-piperazine (H2L) was synthesized through a Schiff
base condensation reaction of salicylaldehyde and 1,4-bis(3-ami-
nopropyl)-piperazine in the presence of P2O5/SiO2 in ethanol (vide
infra). The stoichiometric reaction is shown in Scheme 1:
The organic metal ion binder was subsequently employed in a
reaction with Co(II). The specific reactivity was pursued in a mix-
ture of CHCl3-MeOH, using Co(ClO4)2ꢂ6H2O as a starting material
in MeOH. Et3N was used as a base to deprotonate the acidic phenol
moieties of the H2L ligand, thereby promoting binding to oxidized
Co(III), according to the stoichiometric equation shown in
Scheme 2:
In a third reactivity pattern, Zn(CH3COO)2ꢂ2H2O reacted with
H2L in ethanol, affording a material shown in the stoichiometric
reaction (Scheme 3):
The materials are stable in the air. They are insoluble in water. 1
is soluble in most organic solvents, with 2 being soluble in DMSO
and DMF, and 3 being soluble in chloroform.
(w), 417 (w). Molar conductivity KM, X
ꢀ1 molꢀ1 cm2 (DMF,
4 ꢁ 10ꢀ4 M): 67. UV–Vis (DMF, 4 ꢁ 10ꢀ4 M) kmax [nm] (
e -
/L molꢀ1
cmꢀ1): 383(3100), 497(525), 580(220), 654(140). Fluorescence
(DMF, 20 °C, 5 ꢁ 10ꢀ5 M): kex 293 nm; kem 331 nm.
2.3.3. [Zn2(L)(CH3COO)2] (3)
H2L (0.50 g, 1.2 mmol) in EtOH (15 ml) was slowly treated with
Zn(CH3COO)2ꢂ2H2O (0.53 g, 2.4 mmol) dissolved in EtOH (30 ml).
The yellow solid formed was collected by filtration and washed
with hot ethanol. Yield 0.65 g (82%). Pale yellow crystals were
obtained by crystallization from ethanol-chloroform solutions.
Anal. Calc. for C28H36N4O6Zn2 (655.38): C, 51.32; H, 5.54; N, 8.55;
Zn, 19.95. Found: C, 51.23; H, 5.81; N, 8.47; Zn, 19.78.%. 1H NMR