Two new organic–inorganic complexes associating the radical anion ABTS·– and the inorganic cation Ca2+: Ca0.55(ABTS)(H2O)x and Ca5(ABTS)6(H2O)29

Solid State Sciences 3 (2001) 715–725 www.elsevier.com/locate/ssscie

Two new organic–inorganic complexes associating the radical anion ABTS·– and the inorganic cation Ca2+: Ca0.55(ABTS)(H2O)x and Ca5(ABTS)6(H2O)29 Annaig Denis, Pierre Palvadeau ∗ , Philippe Molinié, Olivier Chauvet, Kamal Boubekeur Institut des Matériaux Jean Rouxel, Chimie des Solides et Physique Cristalline, UMR CNRS 6502, 2 rue de la Houssinière, BP 32229, 44322 Nantes cedex 3, France Received 16 September 2000; accepted 13 February 2001

Abstract The synthesis, crystal structure determination and physical properties of two new charge transfer salts containing the azinobisethylbenzothiazoline (ABTS) anion are described. Electrochemical oxidation in water of the diammonium salt of ABTS in presence of calcium chloride yields black single crystals of two new compounds with different morphologies. The needle-like crystals with Ca0.55 (ABTS)(H2 O)x formula (x depending on the temperature) belong to the monoclinic symmetry, space group C2/c and cell parameters a = 21.568(5), b = 14.535(5), c = 8.0278(17) Å, β = 108.32(3)◦ at room temperature and a = 22.180(4), b = 14.288(3), c = 8.0823(16) Å, β = 108.13(3)◦ , with a lowering of the symmetry, space group Cc, at 200 K. The plate-shaped crystals formulated as Ca5 (ABTS)6 (H2 O)29 belong also to the monoclinic symmetry with P 21 space group and cell parameters a = 11.222(2), b = 37.991(8), c = 19.327(4) Å, β = 106.37(3)◦ at 200 K. The structure analysis of the first phase shows a onedimensional character based on the stacking of organic molecules creating channels in which Ca2+ cations and water molecules are located. The second phase can be described as an alternation of organic and inorganic layers corresponding to a bidimensional hybrid network. The magnetic and electrical properties will be discussed.  2001 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. Keywords: Hybrid materials; ABTS; Calcium; X-ray diffraction; ESR

1. Introduction Previously, we have solved the crystal structure of the diammonium salt of the azinobisethylbenzothiazoline (ABTS2− ) ion in water solutions (C18 H24 O6 N6 S4 · 2H2 O) and in DMF [1,2]. This anion is easily and reversibly oxidized to give the radical anion ABTS·– . The association of this radical anion to the organic cations of TTF derivatives has been demonstrated [2] * Correspondence and reprints.

E-mail address: [email protected] (P. Palvadeau).

with the synthesis of the β-(ABTS)(EDT–TTF)2·(DMF) complex which presents a semiconductor behavior, explained by strong sulfur–sulfur interactions. On the other hand, inorganic cations as Ca2+ together with Anderson’s polyoxometalates yielded by association with the organic EDT–TTF to a bicontinuous hybrid composite χ(2/3–3) (EDT–TTF)8–Ca2 (TeW6 O24 )2 ·30H2 O [3]. It was interesting to check the possibility to associate the radical anion ABTS·− to an inorganic cation. This work deals with the synthesis and the structure determination of new molecular complexes associating ABTS2− and ABTS·− with the alkaline earth cation Ca2+ .

1293-2558/01/$ – see front matter  2001 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. PII: S 1 2 9 3 - 2 5 5 8 ( 0 1 ) 0 1 1 5 9 - 1

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A. Denis et al. / Solid State Sciences 3 (2001) 715–725

2. Experimental 2.1. Electrocrystallisation ABTS(NH4 )2 and CaCl2 ·2H2 O are commercial reagents from Aldrich. Two compartments U-shaped cells with appropriate volume of 20 ml were used for crystal growth by electrocrystallisation. Each cell had two Pt electrodes separated by a porous glass frit. During crystal growth the cell joints were sealed to prevent solvent evaporation. A constant current source was used to control the crystal growth rate and the cells were kept at a constant temperature (295 K). Many experiments were performed versus the concentration of the reactants and the current intensity. The main factor affecting the crystallization appears to be the current intensity. With the same concentration of the reactants (10 mg of CaCl2 ·2H2 O, 37.3 mg of ABTS in 10 ml of water), a large quantity of well-formed black needles were obtained with a 10 µA current. For an intensity of 0.5 µA only plates were formed, and intermediate values of current yield to a mixture of needle- and plateshaped crystals. The reaction time is currently of two or three weeks. Preliminary analyses by scanning electron microscopy give a S/Ca ratio close to 7, in the case of needles and only 4.7 for plates. If such results must be considered with caution, carbon and nitrogen were not taken in account, they are indicative of very different stoichiometries. 2.2. Physical measurements ESR spectroscopic measurements were carried out on single crystal samples oriented according to the applied magnetic field. The X-ray band ESR spectra were performed with a Bruker ER 200D-SRC spectrometer in the temperature range 100–300 K. Primary magnetic studies were carried out on crystalline samples enclosed in a medical capsule. Magnetic susceptibility measurements were performed at 0.5 T after zero field cooling in the temperature range 2–300 K using a commercial SQUID magnetometer MPMS-5S from Quantum Design Corp. The dc electrical conductivity measurements were performed on single crystals within a standard four probes configuration between 100 and 300 K. 2.3. Structure determinations The crystallographic study was performed using a STOE single phi axis diffractometer with a 2D area detec-

tor based on the Imaging Plate technology with Mo-Kα radiation and an Oxford Cryosystem N2 open flow cryostat. A crystal–detector distance of 80 mm has been chosen to keep a good resolution. First X-ray diffraction studies by the Weissenberg technique to select nontwinned crystals showed poor quality diffraction patterns particularly for needles. In view of the low stability of these phases at room temperature due to the presence of very labile water molecules, it has been very difficult to obtain suitable data at room temperature. For this reason, diffraction data were recorded at low temperature. The recording conditions are listed in Table 1. Resulting images were processed with the set of programs from STOE [4]. Cell parameters were refined from 5000 reflections. Structure resolution, refinements were performed using the SHELXTL structural software package [5]. Calcium and sulfur atoms were located from direct methods and the remaining atoms from difference Fourier maps and refined on F 2 by full matrix least squares calculations. Due to the low value of the linear absorption coefficient no absorption corrections were applied. Calcium and sulfur were anisotropically refined for needles and also nitrogen for plates according to the number of reflections. All other atoms were isotropes. Hydrogen positions were calculated.

3. Ca0.55(ABTS)(H2 O)x . Description of crystal structures at 293 K (x = 1.1) and 200 K (x = 3) Among the series of hybrid organic inorganic complexes, it is common to find structural disorder in the organic moieties [6, and references therein]. In our case at 293 K, a strong disorder is present not only for the sulfonate groups at the ends of ABTS anions but also for the calcium sites. This disorder is totally suppressed at 200 K that indicates a dynamic origin. A consequence is the relatively high values of the structural quality criteria. Such a dynamic behavior can explain the transition from the centrosymmetric space group (C2/c) at 293 K to the noncentrosymmetric group at 200 K (Cc). On the other hand, cell parameters change slightly, particularly a which increases from 21.568 to 22.179 Å. Atomic positions and equivalent thermal parameters are gathered in Table 2 and Ca–O distances in Table 3. The crystal structure is built on a superposition of ABTS molecules along the c axis creating channels in which Ca2+ cations and water molecules are localized. This structure can be considered as a one-dimensional network.

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

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Table 1 Crystal data and structure refinement Material

Ca5 (ABTS)6 (H2 O)29

Ca5 (ABTS)6 (H2 O)29

Ca0.55 (ABTS)(H2 O)1.1

Ca0.55 (ABTS)(H2 O)3

Formula weight

3798.39

3798.39

552.67

1045.10

Temperature (K)

160(2)

200(2)

293(2)

200(2)

Wavelength (Å)

0.71073

0.71073

0.71069

0.71073

Crystal system

monoclinic

monoclinic

monoclinic

monoclinic

Space group

P 21

P 21

C2/c

Cc

a (Å)

11.166(2)

11.222(2)

21.568(5)

22.180(4)

b (Å)

37.891(8)

37.991(8)

14.535(5)

14.288(3)

c (Å)

19.285(4)

19.327(4)

8.0278(17)

8.0823(16)

β (◦ )

106.42(3)

106.37(3)

108.32(3)

108.13(3)

Unit cell dimensions:

Volume (Å3 )

7827(3)

7906(3)

2389.0(11)

2434.1(8)

Z

2

2

4

2

Density (calc.) (Mg m–3 )

1.612

1.596

1.537

1.426

Absorption coef. (mm–1 )

0.591

0.585

0.571

0.535

F (000)

3948

3948

1144

1056

Crystal size (mm3 )

0.04 × 0.40 × 0.25

0.05 × 0.55 × 0.30

0.04 × 0.04 × 0.51

0.04 × 0.03 × 0.58

θ range for data collection

1.54–23.96◦

1.89–25.92◦

1.99–25.81◦

1.93–25.72◦

Index ranges

−12 ≤ h ≤ 11

−13 ≤ h ≤ 13

−26 ≤ h ≤ 24

−26 ≤ h ≤ 25

Reflections collected

−42 ≤ k ≤ 43

−46 ≤ k ≤ 46

0 ≤ k ≤ 17

−17 ≤ k ≤ 17

0 ≤ l ≤ 21

0 ≤ l ≤ 23

0≤l≤9

0≤l≤9

22 922

29 442

2281

4342

Independent reflections

22 922

29 442

2281

2239

Completeness to θ =

23.96◦ : 94.8%

25.92◦ : 98.9%

25.81◦ : 99.0%

25.72◦ : 96.6%

Data/restraints/parameters

22 922/1/1175

29 442/1/1190

2281/0/111

2239/2/171

Goodness-of-fit on F 2

0.920

1.124

0.777

1.040

Final R indices [I > 2σ (I )]

R1 = 0.0915

R1 = 0.0908

R1 = 0.0921

R1 = 0.1144

wR2 = 0.2036

wR2 = 0.2206

wR2 = 0.2195

wR2 = 0.2722

Reflections: I > 2σ (I )

11 492

14 603

603

723

R indices (all data)

R1 = 0.1504

R1 = 0.1589

R1 = 0.2334

R1 = 0.2501

wR2 = 0.2593

wR2 = 0.3163

wR2 = 0.2275

wR2 = 0.2572

Abs. struct. param.

0.33(8)

0.40(8)

Largest diff. peak & hole (e Å–3 )

1.156 & –0.830

1.293 & –0.931

At 293 K the three oxygens of sulfonate groups are distributed on nine positions whereas at 200 K, the disorder is removed and they are perfectly localized on three normal positions. The same situation occurs for atomic cal-

0.3(4) 0.632 & –0.395

0.701 & –0.579

cium and water molecule positions. An interesting difference between both temperatures concerns x, the number of water molecules determined from the structure determination and the occupancy factors, x = 1.1 at 293 K

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A. Denis et al. / Solid State Sciences 3 (2001) 715–725

Table 2 Atomic coordinates (× 104 ) and equivalent isotropic displacement parameters (Å2 × 103 ) for Ca0.55 (ABTS)(H2 O)x . U (eq) is defined as one third of the trace of the orthogonalized U ij tensor 200 K

S(1A)

293 K

x

y

z

U (eq)

x

y

z

U (eq)

5830(4)

4029(5)

6330(11)

68(2)

3998(1)

991(2)

271(4)

71(1)

1525(2)

1309(2)

842(6)

96(1)

S(2A)

3468(3)

3623(5)

7170(10)

58(2)

S(3A)

7780(3)

6054(5)

5750(10)

62(2)

S(4A)

10205(3)

6272(5)

5193(11)

62(2)

O(1A)

3011(9)

4348(13)

7590(30)

65(6)

1256(7)

938(14)

2080(20)

65(5)

O(2A)

3725(8)

3060(12)

8600(20)

58(5)

1721(8)

2213(11)

1210(30)

88(5)

O(3A)

3189(7)

3257(11)

5490(20)

55(4)

1063(9)

1189(15)

−1050(30)

107(6)

O(4A)

10608(8)

6239(11)

7060(20)

59(5)

1288(16)

1710(30)

−810(50)

67(9)

O(5A)

10040(8)

7246(13)

4660(20)

65(5)

1139(13)

624(18)

1490(50)

44(7)

O(6A)

10500(9)

5820(13)

4100(30)

69(6)

1893(10)

2085(15)

2350(40)

46(6)

O(7A)

1408(15)

2060(20)

−210(50)

68(10)

O(8A)

1520(20)

1520(30)

2570(60)

131(13)

680(20)

150(60)

97(10)

O(9A)

926(16)

N(1A)

6620(12)

5417(17)

6230(30)

63(7)

4839(3)

−376(5)

157(10)

61(2)

N(2A)

5673(10)

5827(15)

6750(30)

51(6)

3868(4)

−738(5)

674(10)

61(2)

4273(4)

−123(6)

343(12)

55(2)

N(3A)

6946(11)

4641(17)

5840(30)

58(7)

N(4A)

7896(10)

4302(15)

5340(30)

50(6)

C(1A)

6102(15)

5160(20)

6520(40)

67(9)

C(2A)

5165(13)

5379(18)

6790(40)

48(7)

3291(4)

−336(6)

788(13)

58(2)

C(3A)

4670(15)

5870(20)

7210(40)

65(9)

2759(4)

−800(7)

1061(12)

67(3)

C(4A)

4118(15)

5270(20)

7370(40)

58(8)

2225(5)

−276(7)

1081(14)

76(3)

C(5A)

4127(13)

4304(19)

7180(40)

50(8)

2210(5)

671(6)

852(13)

67(3)

C(6A)

4637(15)

3870(20)

6770(40)

58(8)

2746(5)

1120(7)

608(13)

72(3) 56(2)

C(7A)

5145(14)

4395(19)

6690(40)

53(8)

3291(4)

611(6)

554(12)

C(8A)

5828(14)

6852(19)

6950(40)

60(8)

4018(5)

−1730(7)

944(14)

81(3)

C(9A)

5491(14)

7320(20)

5390(40)

66(8)

3698(6)

−2264(9)

−651(17)

114(4)

C(11A)

7519(13)

4921(19)

5690(40)

53(8)

C(12A)

8485(12)

4684(17)

5260(40)

46(7)

C(13A)

8983(13)

4216(19)

4920(40)

51(7)

C(14A)

9501(16)

4680(20)

4900(40)

66(9)

C(15A)

9536(13)

5624(18)

5170(40)

47(7)

C(16A)

8976(17)

6130(20)

5380(50)

70(9)

C(17A)

8475(11)

5592(16)

5500(30)

35(6)

C(18A)

7746(15)

3314(19)

5150(40)

65(9)

C(19A)

8005(15)

2700(20)

6710(50)

83(10)

Ca(1)

1335(5)

4812(7)

3893(17)

73(3)

4681(6)

−4717(9)

−1684(18)

144(4)

O(11)

1385(11)

5439(16)

1550(30)

75(7)

4702(17)

−4110(20)

1260(50)

138(11)

O(12)

2378(11)

5617(15)

4800(30)

83(7)

4910(20)

−3240(30)

−1540(60)

202(19)

O(13)

1854(16)

3320(20)

4230(40)

101(11)

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

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Table 2 (Continued) All atoms are in general positions, except: T (K)

297

200

Atom

O1A

O2A

O3A

O4A

O5A

O6A

O7A

O8A

O9A

Ca1

O11

O12

Ca

SOF

0.5

0.5

0.25

0.25

0.25

0.25

0.25

0.275

0.275

0.275

0.275

0.275

0.55

Table 3 Bond lengths (Å) for Ca0.55 (ABTS)(H2 O)3 at 200 K

4. Crystal structure of Ca5 (ABTS)6 (H2 O)29

Ca(1)–O(11)

2.13(3)

Ca(1)–O(11)1

2.14(3)

Ca(1)–O(12)

2.48(3)

This phase, which corresponds to the plate-shaped crystals, is less stable than the previous phase with needle morphology. A room temperature data collection was not possible to obtain suitable values due to a decay of intensities. In that respect a new data collection was made at 200 K. The structure was solved in the noncentrosymmetric space group P 21 . Atomic positions are given in Table 4. The structural arrangement is very different of that of the needles and is built up on a plane stacked of ABTS molecules separated by mixed layers of Ca2+ cations and water molecules (Fig. 2) leading to a two-dimensional lattice. At 200 K oxygen atoms of one sulfonate group and some water molecules remain disordered. For this reason a new data collection was conducted at lower temperature. This temperature of 160 K was chosen in relation with physical measurements (see below). At this temperature the structure has been solved in the same space group with cell parameters close to those found at 200 K (a = 11.1658(7), b = 37.8913(22), c = 19.2855(13) Å, β = 106.419(7)◦) without disorder. There are six independent ABTS molecules, three are connected to the calcium atoms by oxygen belonging to the sulfonate groups and the others are free. The environment of Ca2+ cations is more complicated. There are five independent positions. The coordination number of the Ca2+ cations oxygen is 6 for Ca1 and 7 for Ca2–Ca5 (Table 5). A schematic representation of the calcium polyhedral arrangement is given in Fig. 2. There are two pairs of Ca2+ , Ca1 and Ca3, on the one hand, and Ca2 and Ca4, on the other hand, are connected by two oxygen atoms belonging to two different sulfonate groups to form dimer entities. Only Ca5 is isolated even if it is also bonded to a sulfonate group by two oxygens. Among the 29 water molecules included in the lattice, 23 of them are involved in the first coordination sphere of the five calciums. The remaining 6 water molecules are free in the structure.

Ca(1)–O(13)

2.39(3)

Ca(1)–O(4A)2

2.36(2)

Ca(1)–O(6A)3

2.39(2)

Symmetry transformations used to generate equivalent atoms: 1 x, −y + 1, z + 1/2;

2 x − 1, −y + 1, z − 1/2;

3 x − 1, y, z.

and x = 3 at 200 K. This difference is explained by the lability of some molecules. At room temperature only the water molecules involved in a bond with a calcium atom (first coordination sphere) are again present in the structure (two for each calcium). There is a lost of the free water molecules at RT confirmed by a thermal analysis. In both cases, the calcium environment is six, made of oxygen atoms belonging either to sulfonate groups (2) or water molecules (4) with two short distances (∼2.12 Å) and four large (∼2.40 Å). Distorted octahedra are connected by two opposite corners forming infinite chains along the c axis. Fig. 1 gives a projection on the ab plane of the structure at 293 K (A) and at 200 K (B), showing the translation of the cell due to the symmetry modification. For clarity hydrogen atoms were removed and the distorted octahedra around Ca2+ were represented only for the structure at 200 K. The bridging oxygen O11 between two octahedra corresponds to the shortest Ca–O distance. A bond valence calculation according to the Brese and O’Keefe’s tables [7] gives for the calcium a value close to 2 (1.98). There is only one independent ABTS molecule with a mean negative value of −1.1 in view of the stoichiometry and this compound appears as an anionic mixed valence compound (ABTS2− )(ABTS·− ). The shortest sulfur–sulfur or nitrogen–nitrogen intermolecular distances are higher than 4 Å and molecular overlappings are not possible in these conditions.

720

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

Fig. 1. Structure of Ca0.55 (ABTS)(H2 )x projections on the ab plane at two temperatures. 297 K: disordered structure, x = 1.1. 200 K: ordered structure, x = 3.

This new hybrid derivative is also an anionic mixed valence compound: (Ca2+ )5 (ABTS2− )4 (ABTS·− )2 . For all structures, anisotropic chemical parameters, bond lengths and angles, hydrogen atomic coordinates, and factor structures are available as supplementary materials (CCDC) in Cambridge. 5. Physical properties Rotation studies on oriented single crystals for both phases give nearly the same extrema for the gyromagnetic factor for the plates gX = 2.0014(2), gY = 2.0025(2) and

gZ = 2.0044(2), and for the needles gX = 2.0012(2), gY = 2.0027(2) and gZ = 2.0044(2), and an isotropic mean value of 2.0030(3) for the two phases. In a previous study of ABTS(NH4 )2 ·2H2 O [1], the spectrum was explained with two Zeeman distributions. The first one is anisotropic with gX = 2.0020(1), gY = 2.0040(1) and gZ = 2.0045(1) ( g = 2.0035(3)) and is attributed to the anhydrous ABTS·− radicals. The second one is isotropic with giso = 2.0040(1) and attributed to the solvated ABTS·− radicals. In fact, the unpaired electrons are delocalized all over the p orbitals. The centroid of this π system is in the neighborhood of the central N–N bond

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

721

Table 4 Atomic coordinates (× 104 ) and equivalent isotropic displacement parameters (Å2 × 103 ) for Ca5 (ABTS)6 (H2 O)29 at 160 K. U (eq) is defined as one third of the trace of the orthogonalized U ij tensor. All atoms are in general positions x

y

z

U (eq)

x

y

S(1A)

5172(4)

4650(1)

1372(2)

23(1)

S(2A)

8145(4)

3460(1)

1439(2)

27(1)

S(3A)

1501(4)

5338(1)

2118(2)

S(4A)

−1548(4)

6507(1)

2029(2)

z

U (eq)

S(1D)

3649(4)

4318(1)

7373(2)

24(1)

S(2D)

6197(4)

3045(1)

7817(2)

21(1)

21(1)

S(3D)

3046(4)

5604(1)

6161(2)

25(1)

24(1)

S(4D)

995(4)

6931(1)

5696(2)

21(1)

N(1A)

3409(13)

4855(3)

2016(6)

24(3)

N(1D)

3805(14)

4938(3)

6688(7)

28(3)

N(2A)

4423(12)

4325(3)

2349(6)

21(3)

N(2D)

5248(13)

4498(3)

6720(6)

25(3)

N(3A)

3381(14)

5143(3)

1538(6)

26(3)

N(3D)

2748(14)

5006(3)

6867(6)

24(3)

N(4A)

2268(13)

5673(3)

1135(6)

21(3)

N(4D)

1305(13)

5472(3)

6754(6)

20(3)

O(1A)

7765(11)

3475(3)

639(6)

39(3)

O(1D)

7310(30)

3014(7)

8423(16)

31(10)

O(2A)

9319(13)

3630(3)

1770(6)

45(3)

O(11D)

7340(20)

3101(6)

8426(11)

3(6)

O(3A)

8109(11)

3108(3)

1686(6)

37(3)

O(2D)

5112(10)

2941(2)

8009(5)

29(2)

O(4A)

−1251(14)

6878(3)

2007(7)

22(3)

O(3D)

6480(30)

2885(8)

7224(17)

33(11)

O(5A)

−2754(16)

6438(4)

1476(8)

34(4)

O(31D)

6330(20)

2817(7)

7226(13)

7(7)

O(6A)

−1552(19)

6388(4)

2720(9)

48(5)

O(4D)

95(10)

7115(2)

5969(5)

25(2)

O(7A)

−2150(30)

6750(8)

1484(16)

22(7)

O(5D)

654(10)

6918(2)

4928(5)

27(2)

O(8A)

−2410(30)

6225(7)

2087(14)

14(6)

O(6D)

2217(11)

7058(3)

6034(6)

36(3)

O(9A)

−850(30)

6608(8)

2772(16)

22(7)

C(1D)

4274(15)

4624(4)

6891(7)

20(3)

C(1A)

4222(16)

4631(4)

1969(8)

24(4)

C(2D)

5622(15)

4153(3)

6957(7)

17(3)

C(2A)

5306(15)

4090(3)

2202(7)

18(3)

C(3D)

6599(17)

3958(4)

6853(8)

31(4)

C(3A)

5635(16)

3771(4)

2489(8)

23(3)

C(4D)

6749(16)

3631(4)

7107(8)

26(4)

C(4A)

6526(15)

3565(4)

2266(7)

23(3)

C(5D)

5911(15)

3482(4)

7474(7)

20(3)

C(5A)

6989(15)

3702(3)

1716(7)

19(3)

C(6D)

4961(15)

3675(3)

7584(7)

17(3)

C(6A)

6628(16)

4035(4)

1414(8)

26(4)

C(7D)

4806(15)

4013(4)

7341(8)

22(3)

C(7A)

5760(16)

4233(4)

1647(8)

22(3)

C(8D)

6036(16)

4722(4)

6369(7)

24(3)

C(8A)

3873(15)

4243(4)

2933(8)

23(3)

C(9D)

5654(18)

4645(4)

5537(9)

36(4)

C(9A)

2653(18)

4019(4)

2631(9)

40(4)

C(11D)

2357(16)

5329(4)

6642(8)

24(4)

C(11A)

2532(14)

5372(3)

1564(7)

15(3)

C(12D)

1079(15)

5807(4)

6534(7)

21(3)

C(12A)

1367(14)

5893(3)

1285(7)

15(3)

C(13D)

127(14)

6041(3)

6568(7)

18(3)

C(13A)

1021(15)

6227(4)

1024(8)

24(3)

C(14D)

95(16)

6369(4)

6311(8)

25(4)

C(14A)

137(14)

6402(3)

1230(7)

14(3)

C(15D)

975(15)

6489(4)

5994(8)

24(3)

C(15A)

−369(14)

6270(3)

1756(7)

17(3)

C(16D)

1955(14)

6276(3)

5937(7)

15(3)

C(16A)

−43(15)

5945(3)

2031(7)

19(3)

C(17D)

1961(15)

5931(4)

6161(7)

20(3)

C(17A)

840(15)

5745(3)

1814(7)

17(3)

C(18D)

593(15)

5279(4)

7194(7)

18(3)

C(18A)

2898(16)

5735(4)

570(8)

28(4)

C(19D)

899(18)

5407(4)

7954(9)

36(4)

C(19A)

4062(18)

5939(4)

795(9)

40(4) S(1E)

−5107(4)

5333(1)

8769(2)

25(1)

S(1B)

11725(4)

4669(1)

4698(2)

24(1)

S(2E)

−8154(4)

6509(1)

8623(2)

23(1)

S(2B)

15023(4)

3561(1)

4926(2)

22(1)

S(3E)

−1469(4)

4637(1)

8013(2)

26(1)

722

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

Table 4 (Continued) S(3B)

8120(4)

5363(1)

5449(2)

22(1)

S(4E)

1611(4)

3474(1)

8126(2)

20(1)

S(4B)

4961(4)

6504(1)

5270(2)

19(1)

N(1E)

−3333(14)

5112(3)

8145(6)

30(4)

N(1B)

9914(13)

4872(3)

5314(6)

25(3)

N(2E)

−4384(13)

5655(3)

7765(6)

26(3)

N(2B)

10956(12)

4337(3)

5660(6)

20(3)

N(3E)

−3281(14)

4827(3)

8619(7)

27(3)

N(3B)

9913(14)

5152(3)

4832(7)

28(3)

N(4E)

−2201(13)

4311(3)

8996(6)

23(3)

N(4B)

8882(12)

5694(3)

4469(6)

18(3)

O(1E)

−7887(10)

6885(3)

8555(5)

31(2)

O(1B)

16017(11)

3812(3)

5038(6)

40(3)

O(2E)

−8119(11)

6410(3)

9353(6)

37(3)

O(2B)

15332(11)

3249(3)

5344(6)

43(3)

O(3E)

−9360(13)

6413(3)

8099(7)

48(3)

O(3B)

14509(12)

3470(3)

4161(6)

45(3)

O(4E)

1432(12)

3559(3)

7366(6)

39(3)

O(4B)

5130(10)

6874(2)

5155(5)

26(2)

O(5E)

1412(11)

3111(3)

8216(5)

35(3)

O(5B)

5134(10)

6437(2)

6033(5)

28(2)

O(6E)

2827(13)

3577(3)

8610(6)

45(3)

O(6B)

3772(13)

6365(3)

4798(6)

49(3)

C(1E)

−4113(15)

5356(4)

8181(7)

20(3)

C(1B)

10750(16)

4646(4)

5283(8)

30(4)

C(2E)

−5215(16)

5885(4)

7946(8)

25(4)

C(2B)

11876(15)

4115(4)

5546(7)

23(3)

C(3E)

−5598(16)

6211(4)

7651(8)

24(3)

C(3B)

12259(13)

3796(3)

5846(7)

14(3)

C(4E)

−6453(15)

6401(4)

7849(7)

20(3)

C(4B)

13252(15)

3619(4)

5681(7)

24(3)

C(5E)

−6969(16)

6257(4)

8386(8)

27(4)

C(5B)

13763(15)

3762(4)

5151(7)

21(3)

C(6E)

−6626(15)

5942(4)

8691(8)

21(3)

C(6B)

13297(15)

4080(3)

4808(7)

21(3)

C(7E)

−5788(15)

5754(4)

8448(7)

19(3)

C(7B)

12369(16)

4258(4)

4990(8)

26(3)

C(8E)

−3696(16)

5742(4)

7240(8)

26(4)

C(8B)

10424(15)

4264(4)

6263(8)

25(3)

C(9E)

−2590(20)

5980(5)

7526(10)

45(5)

C(9B)

9238(17)

4020(4)

6000(9)

38(4)

C(11E)

−2476(16)

4605(4)

8591(8)

26(4)

C(11B)

9157(14)

5391(3)

4887(7)

19(3)

C(12E)

−1308(16)

4084(4)

8874(8)

26(4)

C(12B)

8024(14)

5918(3)

4629(7)

18(3)

C(13E)

−911(14)

3774(3)

9161(7)

15(3)

C(13B)

7618(14)

6240(4)

4329(7)

21(3)

C(14E)

44(15)

3578(4)

8973(7)

23(3)

C(14B)

6713(14)

6418(4)

4516(7)

22(3)

C(15E)

447(14)

3712(3)

8401(7)

17(3)

C(15B)

6180(15)

6273(4)

5036(8)

24(3)

C(16E)

61(16)

4035(4)

8084(8)

26(4)

C(16B)

6561(15)

5961(4)

5338(8)

22(3)

C(17E)

−843(15)

4219(4)

8302(8)

22(3)

C(17B)

7498(15)

5772(4)

5154(7)

19(3)

C(18E)

−2797(16)

4234(4)

9566(8)

26(4)

C(18B)

9567(15)

5768(4)

3919(8)

26(4)

C(19E)

−3928(16)

3972(4)

9278(8)

33(4)

C(19B)

10737(19)

5982(5)

4190(10)

50(5) S(1F)

6961(4)

4412(1)

4011(2)

24(1)

426(4)

4334(1)

685(2)

22(1)

S(2F)

9049(4)

3089(1)

4540(2)

19(1)

S(1C) S(2C)

2731(4)

3030(1)

986(2)

20(1)

S(3F)

6363(4)

5688(1)

2762(2)

22(1)

S(3C)

−264(4)

5608(1)

−509(2)

25(1)

S(4F)

3679(4)

6927(1)

2056(2)

23(1)

S(4C)

−2491(4)

6927(1)

−898(2)

25(1)

N(1F)

7251(13)

5007(3)

3292(6)

22(3)

N(1C)

600(14)

4942(3)

−20(7)

29(3)

N(2F)

8582(14)

4530(3)

3338(7)

28(3)

N(2C)

2109(13)

4509(3)

56(7)

23(3)

N(3F)

6210(13)

5080(3)

3482(6)

26(3)

N(3C)

−485(13)

5004(3)

186(6)

25(3)

N(4F)

4691(13)

5518(3)

3389(7)

25(3)

N(4C)

−2017(13)

5456(3)

85(7)

23(3)

O(1F)

10038(10)

2915(2)

4334(5)

30(2)

O(1C)

1496(11)

2884(3)

702(6)

37(3)

O(2F)

9263(10)

3136(2)

5310(5)

25(2)

O(2C)

3615(10)

2868(2)

674(5)

28(2)

O(3F)

7822(11)

2937(3)

4201(5)

30(2)

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

723

Table 4 (Continued) O(3C)

3146(10)

3025(3)

1751(5)

31(2)

O(41F)

3376(10)

6858(3)

1286(5)

31(2)

O(4C)

−1275(11)

7032(3)

−1002(5)

34(3)

O(5F)

4808(11)

7114(3)

2341(5)

34(3)

O(5C)

−2680(10)

7136(2)

−300(5)

30(2)

O(61F)

2583(9)

7074(2)

2227(5)

23(2)

O(6C)

−3472(10)

6944(2)

−1528(5)

27(2)

C(1F)

7632(14)

4685(3)

3498(7)

15(3)

C(1C)

1080(15)

4639(4)

204(7)

20(3)

C(2F)

8856(15)

4184(3)

3601(7)

19(3)

C(2C)

2385(15)

4162(3)

266(7)

18(3)

C(3F)

9854(15)

3629(4)

3801(7)

21(3)

C(3C)

3363(15)

3966(3)

185(7)

19(3)

C(4F)

9753(15)

3971(4)

3521(7)

21(3)

C(4C)

3482(15)

3623(4)

415(7)

20(3)

C(5F)

8965(15)

3520(4)

4163(7)

24(3)

C(5C)

2637(14)

3470(4)

745(7)

20(3)

C(6F)

8055(14)

3748(3)

4261(7)

18(3)

C(6C)

1666(15)

3680(3)

825(7)

19(3)

C(7F)

8022(16)

4073(4)

3989(8)

27(4)

C(7C)

1572(15)

4026(4)

635(7)

22(3)

C(8F)

9390(15)

4712(4)

2942(7)

18(3)

C(8C)

2822(15)

4713(4)

−355(7)

19(3)

C(9F)

9078(16)

4578(4)

2131(8)

24(3)

C(9C)

2419(17)

4602(4)

−1174(8)

29(4)

C(11F)

5778(14)

5397(3)

3267(7)

13(3)

C(11C)

−910(14)

5313(3)

−23(7)

16(3)

C(12F)

4394(15)

5855(4)

3136(7)

19(3)

C(12C)

−2257(16)

5792(4)

−134(8)

24(4)

C(13F)

3385(16)

6049(4)

3184(8)

26(4)

C(13C)

−3177(15)

6017(3)

−42(7)

19(3)

C(14F)

3146(15)

6381(3)

2852(7)

16(3)

C(14C)

−3238(17)

6355(4)

−288(8)

34(4)

C(15F)

3914(14)

6501(4)

2488(7)

16(3)

C(15C)

−2379(14)

6488(4)

−620(7)

19(3)

C(16F)

5004(16)

6316(4)

2453(8)

26(4)

C(16C)

−1405(15)

6274(4)

−718(7)

23(3)

C(17F)

5196(15)

5986(3)

2766(7)

18(3)

C(17C)

−1398(13)

5936(3)

−469(6)

9(3)

C(18F)

3993(16)

5308(4)

3799(8)

26(4)

C(18C)

−2705(15)

5265(4)

520(7)

22(3)

C(19F)

4159(17)

5426(4)

4559(8)

35(4)

C(19C)

−2370(18)

5370(4)

1307(9)

38(4)

66(3)

7468(1)

−320(1)

25(1)

O(11)

879(8)

7497(3)

−1302(4)

O(12)

1610(11)

7930(3)

133(5)

O(13)

1500(12)

7009(3)

O(14)

−120(11)

7409(3)

Ca(1)

Ca(2)

Ca(4)

−1638(3)

7532(1)

5686(1)

26(1)

30(2)

O(41)

−2658(12)

7076(3)

6105(6)

44(3)

32(3)

O(42)

−2351(11)

8060(3)

6164(5)

36(3)

100(6)

44(3)

O(43)

−604(8)

7524(3)

6987(4)

28(2)

841(6)

49(3)

3504(3)

7528(1)

6586(1)

19(1)

O(44)

−3543(12)

7680(3)

4834(6)

50(3)

O(45)

−1587(12)

7287(3)

4532(6)

50(3)

O(21)

4074(8)

7502(3)

5473(4)

24(2)

Ca(5)

2277(3)

7429(1)

3171(1)

20(1)

O(22)

5001(11)

7999(3)

6782(5)

33(3)

O(51)

2521(10)

7854(2)

4096(5)

29(2)

O(23)

4937(10)

7042(3)

6941(5)

28(2)

O(52)

2175(10)

6944(3)

3979(5)

34(2)

O(24)

1953(10)

7597(2)

7216(5)

37(3)

O(53)

952(11)

7773(3)

2188(6)

42(3)

O(25)

4469(11)

7635(3)

7864(6)

43(3)

O(54)

147(11)

7327(3)

3159(6)

40(3)

O(55)

4399(10)

7239(3)

3763(5)

33(2)

1174(12)

3152(3)

2398(6)

44(3)

Ca(3)

−4199(3)

7453(1)

110(1)

25(1)

O(31)

−4363(12)

7997(3)

733(6)

40(3)

O(600)

O(32)

−4478(11)

6924(3)

720(6)

39(3)

O(700)

1233(11)

1897(3)

2481(6)

37(3)

O(33)

−2394(10)

7457(3)

1156(5)

44(3)

O(61)

8869(11)

7926(3)

3458(5)

38(3)

O(34)

−6279(14)

7478(5)

130(7)

82(4)

O(62)

6521(16)

7685(4)

3412(8)

79(4)

O(35)

−5484(12)

7158(3)

−1000(6)

51(3)

O(63)

7255(15)

6960(4)

3306(8)

74(4)

724

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

Fig. 2. Ca5 (ABTS)6 (H2 O)29 , projection on the bc plane showing the stacking of organic entities and the connections with calcium polyhedra. Only one molecule is isolated.

of the molecule. Normally, the length of this bond must be sensitive to the charge of the ABTS molecule. Here, for the two hybrids, the radicals are identical, anisotropic and belong to the same π system as described previously. For the plates, one third of ABTS can be considered as radicals according to the stoichiometry point of view. The X-ray diffraction study at 160 K defined two groups of ABTS species: four with an N–N bond length of 1.41(2) Å and two with 1.34(2) Å. From the magnetic studies, the plates show a paramagnetic behavior at low temperature (T < 150 K) but the determined spin number is lower than the expected one. This may indicate a slight dimerization of the ABTS stacking. From ESR studies, a structural transition appears in the temperature range 180–240 K, it is observed in the linewidth variations for the three directions X, Y and Z. This transition may be due, on the one hand, to the disymmetrical appearance

of the central bonds C–N–N–C of the ABTS, as shown by the X-ray diffraction at 200 K, and on the other hand, to the possible intersite exchange of spin radical between two ABTS anions (E and F). Electrical measurements on the plates indicate a semiconductor behavior with an order–disorder transition (as indicated by structural results) at ∼210 K with two values of the activation energy 0.28 eV (above) and 0.21 eV below (Fig. 3). In the needles, the ABTS are almost in radical form by stoichiometry but the X-ray diffraction at 200 K shows an N–N bond length of 1.41(2) Å close to those of ABTS(NH4 )2 ·2H2 O (1.41(1) Å) [1]. Magnetic studies show a very low content of paramagnetic species, about 1% of the expected value which is coherent with the observed X-ray N–N bond length and may also indicate a dimerization of the ABTS stacking.

A. Denis et al. / Solid State Sciences 3 (2001) 715–725

725

Table 5 Bond lengths (Å) for Ca5 (ABTS)6 (H2 O)29 at 160 K. Ca(1)–O(11)

2.322(9)

Ca(1)–O(12)

2.439(11)

Ca(1)–O(13)

2.347(13)

Ca(1)–O(14)

2.316(11)

Ca(1)–O(1C)1

2.312(12)

Ca(1)–O(4C)

2.365(11)

Ca(2)–O(21)

2.407(8)

Ca(2)–O(22)

2.402(11)

Ca(2)–O(23)

2.408(11)

Ca(2)–O(24)

2.394(10)

Ca(2)–O(25)

2.429(11)

Ca(2)–O(6D)

2.347(11)

Ca(2)–O(3F)2

2.372(11)

Ca(3)–O(31)

2.419(11)

Ca(3)–O(32)

2.390(11)

Ca(3)–O(33)

2.416(11)

Ca(3)–O(34)

2.336(15)

Ca(3)–O(35)

2.479(13)

Ca(3)–O(2C)1

2.397(9)

Ca(3)–O(5C)

2.386(10)

Ca(4)–O(41)

2.338(12)

Ca(4)–O(42)

2.427(10)

Ca(4)–O(43)

2.447(9)

Ca(4)–O(44)

2.359(13)

Ca(4)–O(45)

2.427(12)

Ca(4)–O(4D)

2.439(10)

Ca(4)–O(1F)2

2.308(11)

Ca(5)–O(51)

2.361(9)

Ca(5)–O(52)

2.433(10)

Ca(5)–O(53)

2.429(12)

Ca(5)–O(54)

2.404(12)

Ca(5)–O(55)

2.430(11)

Ca(5)–O(3D)2

2.47(3)

Ca(5)–O(31D)2

2.42(2)

Symmetry transformations used to generate equivalent atoms: 2 −x + 1, y + 1/2, −z + 1.

1 −x, y + 1/2, −z;

Fig. 3. Resistivity measurement of Ca5 (ABTS)6 (H2 O)29 .

6. Conclusions Using the electrocrystallization technique, it has been possible to obtain the first organic–inorganic complexes based on the ABTS anion. The calcium atom is not the most interesting for physical properties. However, more details of magnetic properties and X-ray conformation of the ABTS stacking in these phases will be given in a future publication including new experimental data. Recently we have obtained new phases with rare earths and transition metals (iron, copper, etc.) and their properties are currently intensively studied.

References [1] S. Thérias, C. Mousty, B. Aboab, P. Molinié, M. Queignec, P. Léone, C. Rossignol, P. Palvadeau, New J. Chem. 12 (1997) 1321. [2] P. Palvadeau, A. Denis, K. Boubekeur, S. Thérias, C. Mousty, P. Molinié, O. Chauvet, Chem. Mat. (submitted). [3] K. Boubekeur, R. Riccardi, P. Batail, E. Canadell, C. R. Acad. Sci. Paris Sér. IIc 1 (1998) 627. [4] STOE IPDS Software Manual, V.2.75, STOE & Cie, Darmstadt, 1996. [5] G.M. Sheldrick, SHELXTL 5.1, Brucker AXS Inc., Madison, WI, USA, 1997. [6] L. Martin, S.S. Turner, P. Day, P. Guionneau, J.A.K. Howard, M. Uruichi, K. Yakushi, J. Mater. Chem. 9 (1999) 2731. [7] N.E. Brese, M. O’Keefe, Acta Cryst. B 47 (1991) 192.