Coordination properties of N-p-tolylsulfonyl-l -glutamic acid toward metalII

Polyhedron 18 (1999) 1975–1982

Coordination properties of N-p-tolylsulfonyl-L-glutamic acid toward metal II Part 1. Crystallographic study on Zn II and Cd II complexes a a a a, b A. Bonamartini Corradi , G. Lusvardi , L. Menabue , M. Saladini *, P. Sgarabotto a

b

Dipartimento di Chimica, Universita` di Modena, via Campi 183, 41100 Modena, Italy Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Centro di Studi per La strutturistica Diffrattometrica del CNR, Universita` di Parma, via delle Scienze, 43110 Parma, Italy Received 11 December 1998; accepted 15 February 1999

Abstract A series of compounds of N-p-tolylsulfonyl-L-glutamic acid with divalent Cu, Zn and Cd are synthesized and characterized. For the complexes [Zn(tsgluO)(H 2 O) 2 ]?H 2 O (1), [Cd 2 (tsgluO) 2 (H 2 O) 6 ] (2) and [Cd(bipy)(tsgluO)] (3) the crystal and molecular structure have been determined by X-ray diffraction (tsgluO5N-p-tolylsulfonyl-L-glutamate dianion, bipy52,29-bipyridine). In compound 1 the Zn II ion exhibits a tetrahedral geometry arising from coordination of two carboxylic oxygens of two amino acid molecules and of two water molecules. In compound 2 each Cd II ion of the dimeric unit is coordinated by oxygen atoms of tsgluO 22 and water molecules in a distorted octahedral environment. In compound 3 the Cd II ion is coordinated by 2,29-bipyridine nitrogens and four oxygen atoms from three different tsgluO 22 in a distorted octahedral geometry.  1999 Elsevier Science Ltd. All rights reserved. Keywords: Divalent metals; Copper; Zinc; Cadmium; N-p-tolylsulfonyl-L-glutamic acid; Compounds

1. Introduction Among naturally occurring amino acids of biological importance, aspartic and glutamic acids are characterized by the presence of two carboxyl functions which make them potentially tridentate ligands, and a variety of coordination modes is observed [1–6]. In the highly hydratated complexes they act as simple bidentate N,O-chelate glycine-like ligands forming monomeric species as in Cu(Glu)?3H 2 O [3], [Cu(Asp)(bipy)? H 2 O]?3H 2 O [4]. In the low hydratated or anhydrous complexes the second carboxyl group in b- and g-position with respect to amine function, in aspartic (Asp) and glutamic (Glu) acid, respectively, is also involved in metal coordination as in Cu(Glu)(Im) [5], Cu(Asp)(Im)?2H 2 O [6], giving rise to polymeric species. The substitution of an Ar-SO 2 -group on the amine nitrogen of amino acids such as glycine, DL-a- and b-

*Corresponding author. Tel.: 139-59-378-424; fax: 139-59-373-543. E-mail address: [email protected] (M. Saladini)

alanine leads their coordination modes to be metal- and pH-dependent. At low pH the only binding site is the carboxyl group irrespective of the metal ion involved. At increasing pH, with metal ions such as Pd II , Pb II , Cu II , Cd II , the deprotonation reaction of the sulfonamide nitrogen takes place in the order of increasing pH: Pd II ,Pb II , Cu II ,Cd II with a pKNH in the range 1–10; for the free Ar-SO 2 -N-amino acids the mean pKNH value is 11.5 [7]. The ability of Ar-SO 2 -N-amino acids to coordinate all of the above cited metal ions through the deprotonated sulfonamide nitrogen is fully confirmed by a number of crystallographic studies [8–10] and by spectrophotometric analysis (UV and NMR) [7,11,12]. For Cu II the reaction does not take place with Ar-SO 2 b-alanine in view of the lower stability of six-membered chelate rings with respect to five-membered ones, and metal hydrolysis prevails. The addition of 2,29-bipyridine allows the formation of mixed [M II (bipy)(LO) x ] (x51 or [M( bipy)] M 2) species, and Dlog K5log K [M( bipy)LO] 2log K M(LO) is positive, indicating a stabilization of the mixed complex with respect to the simple carboxylate one. These results can be interpreted as due to the extended conjugation between the p orbitals of the aromatic amine and aryl group of the amino acidic moiety and to the preference of

0277-5387 / 99 / $ – see front matter  1999 Elsevier Science Ltd. All rights reserved. PII: S0277-5387( 99 )00093-5

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

1976

Nomenclature

bipy H 2 tsglu LO tsglu,O 22 tsgluN,O 32

2,29-bipyridine N-p-tolylsulfonyl-L-glutamic acid Ar-SO 2 -N-aminoacidate monanion N-p-tolylsulfonyl-L-glutamate dianion N-p-tolylsulfonyl-L-glutamate trianion

oxygen donor ligands toward [M(bipy)] 21 species with respect to the free M II ion. The formation of stable mixed complexes, separated also in the solid state as [M II (bipy)(LO) 2 ]?xH 2 O [LO5Np-tolylsulfonylglycinate, M II 5Cu II , x51; M II 5Pb II , x50; M II 5Cd II , x50; LO5N-p-tosylsulfonyl-b-alaninate, M II 5 Cu II , x50], enables the deprotonation and metal coordination of sulfonamide nitrogen of Ar-SO 2 derivatives of glycine and DL-a-alanine also for Zn II [11], Co II and Ni II [13] ions. The same reaction also takes place for b-alanine derivatives in the presence of Cu II [14]. Similarly to what has previously been observed with glycine derivatives, the Ar-SO 2 -N-aspartic and -glutamic acids are expected to present a different coordination behavior with respect to parent ligands. At low pH their active binding sites can only be the carboxylate groups, but the second carboxyl group should affect the conditions for the sulfonamide nitrogen deprotonation. In fact the deprotonation of the double negatively charged anion, to give a trinegative one, can be reasonably reached at a pH value higher relative to glycine derivatives, and the metal hydrolysis can precede this reaction. We now report the results on the solid and solution study on binary M II -N-p-tolylsulfonyl-L-glutamic acid (H 2 tsglu) [M II 5Cu II , Cd II , Zn II , Pb II ] and ternary 2,2bipyridine containing systems, in order to explore the effect of the second carboxyl group on the coordination behavior of the amino acid and on the conditions favoring the metal coordination of the sulfonamide nitrogen. In view of the great amount of results, we decided to report in Part 1 the study on solid complexes and in Part 2 the results on solution investigation.

2. Experimental All chemicals were of the highest purity commercially available.

solved in hot water (25 cm 3 ) and then added to an ethanolic solution (20 cm 3 ) of H 2 tsglu (0.301 g, 1.00 mmol). By cooling the solution at room temperature a green microcrystalline compound separated (yield 80%). Found: C, 38.1; H, 3.7; N, 3.7; S, 8.3%. Calculated for C 12 H 15 CuNO 7 S: C, 37.8; H, 4.0; N, 3.7; S, 8.4%.

2.1.2. K[ Cu(tsgluN,O)]?3 H2 O The hot solution from which the carboxylate complex separated was treated with KOH until pH 9. After addition of diethylendioxide (20 cm 3 ) a blue microcrystalline compound separated (yield 50%). Found: C, 31.7; H, 3.7; N, 3.0; S, 6.9%. Calculated for C 12 H 18 CuKNO 9 S: C, 31.6; H, 4.0; N, 3.0; S, 7.0%. 2.1.3. M(tsgluO)?3 H2 O ( M5 Zn II or Cd II) M(CH 3 COO) 2 ?xH 2 O (M5Zn II 0.219 g, M5Cd II 0.266 g, 1 mmol) was dissolved in water (25 cm 3 ) and then added to an ethanolic solution (25 cm 3 ) of H 2 tsglu (0.376 g, 1.25 mmol). By slow evaporation of the solution, crystalline compounds separated (yield 70%). Found: C, 34.4; H, 4.7; N, 3.2; S, 7.8%. Calculated for C 12 H 19 ZnNO 9 S: C, 34.4; H, 4.8; N, 3.3; S, 7.7%. Found: C, 29.9; H, 4.2; N, 3.1; S, 7.0%. Calculated for C 12 H 19 CdNO 9 S: C, 30.9; H, 4.3; N, 3.0; S, 6.9%. 2.1.4. [ M( bipy)(tsgluO)] ( M5 Cu II , Cd II) The corresponding binary complex (M5Zn II 0.199 g, M5Cd II 0.242 g, 0.5 mmol) was dissolved in C 2 H 5 OH (25 cm 3 ) and added to an ethanolic solution (10 cm 3 ) of 2,29 bipyridine (0.078 g, 0.5 mmol). By slow evaporation at room temperature solid crystalline compounds separated (yield 70%). All attempts to obtain the bipy adduct of the other metals failed. Found: C, 50.9; H, 4.2; N, 8.1; S, 6.0%. Calculated for C 22 H 21 CuN 3 O 6 S: C, 50.9; H, 4.1; N, 8.1; S, 6.2%. Found: C, 46.5; H, 3.7; N, 7.3, S, 6.2%. Calculated for C 22 H 21 CdN 3 O 6 S: C, 46.5; H, 3.7; N, 7.4, S, 5.6%. 2.2. Analysis and physical measurements Nitrogen, carbon, hydrogen and sulfur were determined with a C.ERBA Mod. 1106 Elemental Analyzer by Mr. G. Pistoni. The electronic spectra of the copper compounds at room temperature were recorded with a Perkin-Elmer Lambda 19 spectrophotometer equipped with a DM60 integration sphere. The ESR spectra of the copper compounds were obtained with a Bruker ER 200-SRC Spectrometer by using the X-band at 160 and 239 K. The infrared spectra (4000–400 cm 21 ) were recorded with an FT-IR Bruker 113v spectrometer in KBr pellets.

2.1. Preparation of the complexes 2.3. X-ray data collection and structure refinement 2.1.1. Cu(tsgluO)? H2 O Cu(CH 3 COO) 2 ?H 2 O (0.200 g, 1.00 mmol) was dis-

Lattice constants for all the complexes were determined

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

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Table 1 Experimental data for the X-ray diffraction studies on crystalline compounds 1, 2 and 3 Compound

1

2

3

Formula M F(000) Cryst. syst. Space group ˚ a, A ˚ b, A ˚ c, A b, deg. ˚3 U, A Z d calc , g cm 23 d obs , g cm 23 Cryst. dimensions, mm m (Mo-Ka), cm 21 Diffractometer 2u range, deg. hkl range Unique total data Unique obs. data, I .2s (I) No. of defined par. R Rw GOF ˚ 23 Largest residue peak, eA

C 12 H 19 NO 9 SZn 418.7 864 Orthorhombic P2 1 2 1 2 1 (No. 19) 23.072(4) 9.739(2) 7.413(2) 90 1665.7(6) 4 1.67 1.70 0.1230.1230.38 16.4 Enraf-Nonius CAD 4 6–56 6h, k, l 3214 1596 233 0.055 0.058 0.630 1.11

C 24 H 32 CdN 2 O 15 S 2 877.4 876 Monoclinic P2 1 (No. 4) 7.408(2) 13.916(3) 15.263(3) 99.9(1) 1550.0(8) 2 1.88 1.85 0.0730.1230.19 15.8 Siemens AED 6–56 6h, k, l 2950 2230 437 0.030 0.031 0.610 0.78

C 22 H 21 CdN 3 O 6 S 567.7 1144 Monoclinic C2 (No. 5) 24.386(3) 5.042(1) 18.349(2) 93.2(1) 2252.5(6) 4 1.67 1.70 0.3030.2030.40 11.0 Siemens M18X P4 / RA 5–60 h, k, 6l 3769 3550 149 0.046 0.056 0.262 1.23

by least-squares refinement of the angular settings of 30 centred reflections. Crystal data are summarized in Table 1. Intensity data were collected at 295 K using Mo K a ˚ with the u 22u scan technique. radiation ( l50.71069 A) All data were corrected for Lorentz and polarization effects and an empirical absorption correction for complex 1 was applied following Walker and Stuart [15] (absorption correction min–max 0.667–1.00). A correction based on c scan [16] was applied in 3 (absorption correction min–max 0.60–0.61), while no absorption correction was applied for 2 in view of the small crystal dimensions. The structures were solved by conventional Patterson and Fourier techniques and refined through full-matrix least-squares calculations minimising Sw(uFo u2uFc u)2 . Anisotropic refinements were carried out for all non-hydrogen atoms. Hydrogen atoms were located in a difference map and refined with isotropic thermal parameters in 1 and 2, as fixed contributors in 3. All calculations were performed using SHELX86 [17], SHELX76 [18], PARST [19], CRYSRULER [20] and ORTEP [21] programs.

copper II -acetate like structure [22]. The ESR spectrum at room temperature shows signals in the spectral range typical of the monomeric species and only small evidence of the dinuclear complex; at 160 K the resolution of the signal due to the monomer is improved and the g values can be evaluated ( gi 52.37; g' 52.09; A i 310 4 cm 21 5 159), whereas the improvement of the resolution of the dimer signals is not enough to calculate its g values.

3. Results and discussion

3.1.3. Crystal structure of [ Zn(tsgluO)( H2 O)2 ]? H2 O (1) The crystal structure is reported in Fig. 1 and the main bond distances and angles are reported in Table 2. The Zn II atom is coordinated by two carboxyl groups, belonging to two different amino acidic moieties and two water molecules to give a distorted tetrahedral geometry. The C(1)– C(5) chain of the glutamate moiety is in the extended form and coordinates two symmetry-related Zn II ions through

3.1. Binary complexes 3.1.1. Cu(tsgluO)? H2 O The electronic spectrum of the green Cu II complex shows a d–d band maximum centred at 14 400 cm 21 and a shoulder at 26 400 cm 21 , characteristic of binuclear

3.1.2. K[ Cu(tsgluNO)]?3 H2 O The electronic spectrum of this compound presents a broad maximum which can be divided into two components at 17 400 and 15 000 cm 21 , with a shift toward the high energy region with respect to the previous Cu(tsgluO)?H 2 O compound. The shift is in line with a change from an oxygen donor atom set to a mixed N,Odonor atom set and with a tetragonally distorted coordination geometry [23] as a consequence of the bonding also through the deprotonated sulfonamide nitrogen. The ESR parameters, ( gi 52.19; g' 52.06), are consistent with the proposed geometry.

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

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Fig. 1.

ORTEP

view of 1 (thermal ellipsoids 50%, here and below) with the atom numbering scheme.

the carboxyl groups acting as monodentate, giving rise to a polymeric chain running along the b axis. The –S–C 6 H 4 –CH 3 group is maintained nearly parallel to the aliphatic chain by means of intra- and intermolecular hydrophobic interaction between the hydrogens of C(4) ˚ and the carbons of the phenyl ring (range 2.90–3.50 A). The bond distances and angles at Zn II ion are in the range expected for the tetrahedral geometry. The disposition assumed by the ligand is associated with Zn–O(12) and ˚ respectiveZn–O(52) distances of 2.84(1) and 2.954(8) A, ly, close to the sum of the corresponding van der Waals ˚ [24,25]. radii (2.91 A) The unidentate coordination of the carboxyl is consistent with the uncommon tetrahedral geometry in carboxylate complexes [26]. The bond distances and angles in the tsgluO 22 dianion are in agreement with the corresponding ones in the Ar-SO 2 -N-glycinate monoanions [7,13] and in the glutamate anion [2]. In the carboxyl groups the C–O distance involving the metal coordinated oxygen is only slightly longer than the other, because O(12) and O(52) form short contacts with water oxygens. The oxygen atoms of all water molecules are involved in a network of short intra- and intermolecular contacts ˚ (2.63(1)–2.81(1) A), contributing to packing stability, along with the nitrogen atom, which forms an intermolecular hydrogen bond with the sulfonic O(1) atom.

3.1.4. Crystal structure of [ Cd2 (tsgluO)2 ( H2 O)6 ] (2) Selected interatomic distances and angles are reported in Table 2 with atom numbering in Fig. 2. The unit cell contains two crystallographically independent Cd II atoms in a distorted octahedral environment, two tsgluO 22 anions and three water molecules. Cd(1) is coordinated to five oxygens belonging to four tsgluO 22 anions and one water molecule. The carboxylate oxygens are: O(151) of gcarboxyl acting as monoatomic bridges; O(111) of the

a-carboxyl of a second molecule; O(251) and O(252) of the bidentate chelate g-carboxyl of a third molecule; O(211) of the a-carboxyl of the fourth ligand molecule. Cd(2) is coordinated to both the independent tsgluO 22 through O(212) and O(151) of a and g-carboxyl. In addition, two other tsgluO 22 coordinate Cd(2) through O(112) and O(251), respectively. The coordination is completed by Ow(2) and Ow(3). One tsgluO 22 acts as bidentate bridging ligand through the a-carboxyl oxygens and monoatomic bridging through the g-carboxyl, and coordinates three Cd atoms. The acarboxyl of the second amino acid dianion is also bidentate bridging, while the g-carboxyl is bidentate chelate and monoatomic bridging, and this second ligand coordinates four Cd atoms. Thus, a tridimensional polymeric arrangement is built up into adjacent octahedra alternately connected by O(151) and O(251). Fig. 3 displays a projection of the polymeric trend along the a axis. The different binding mode of g-carboxyl for the two tsgluO 22 entities can be considered mainly responsible for the greater distortion from regular octahedron observed for Cd(1), with respect to Cd(2). In fact, the bidentate chelate and monoatomic bridging coordination mode of one gcarboxyl group leads to a larger range of Cd(1)–O ˚ as compared to the distances (2.211(7)–2.400(6) A) ˚ and to a great Cd(2)–O range (2.240(7)–2.350(7) A) deviation of O–Cd–O angles from the ideal value of 1808 (range 150.0(2)–157.5(3)8) and 908 (range 54.7(2)– 99.8(3)8) expected for a regular octahedron. The distances and angles within the ligands are comparable to those of Zn II complex, and the only difference between the two independent amino acidic molecules is with regards to the C–O distance in the monoatomic bridging g-carboxyl; the distance at the metal coordinated ˚ than the other (1.228(11) oxygen is longer (1.300(12) A) ˚ The N(1) atom forms an intramolecular short hydrogen A). bond with the O(152) atom.

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

1979

Table 2 ˚ and angles (deg.) with e.s.d.’s in parentheses on the coordination polyhedra Bond distances (A) Compound 1 Zn–O(11) Zn–O(51)I

1.938(8) 1.943(8)

O(11)–Zn–O(51)I O(11)–Zn–Ow(1) O(11)–Zn–Ow(2)

104.1(4) 118.7(3) 102.9(4)

Compound 2 Cd(1)–O(111)II Cd(1)–O(151) Cd(1)–O(211) Cd(1)–O(251)III Cd(1)–O(252)III Cd(1)–Ow(1)

2.276(6) 2.211(7) 2.261(7) 2.400(6) 2.318(7) 2.349(8)

O(111)II –Cd(1)–O(151) O(111)II –Cd(1)–O(211) O(111)II –Cd(1)–O(251)III O(111)II –Cd(1)–O(252)III O(111)II –Cd(1)–Ow(1) O(151)–Cd(1)–O(211) O(151)–Cd(1)–O(251)III O(151)–Cd(1)–O(252)III O(151)–Cd(1)–Ow(1) O(211)–Cd(1)–O(251)III O(211)–Cd(1)–O(252)III O(211)–Cd(1)–Ow(1) O(251)III –Cd(1)–O(252)III O(251)III –Cd(1)–Ow(1) O(252)III –Cd(1)–Ow(1) Cd(1)–O(151)–Cd(2) Compound 3 Cd–O(11)V Cd–O(12) Cd–O(51)VI

109.2(3) 85.7(3) 76.6(2) 91.2(3) 150.0(2) 99.8(3) 156.8(2) 102.2(3) 99.6(3) 103.0(3) 157.5(3) 81.2(3) 54.7(2) 80.3(2) 90.8(3) 103.4(3)

2.316(5) 2.284(5) 2.362(6)

O(11)V –Cd–O(12) O(11)V –Cd–O(51)VI O(11)V –Cd–O(52)VI O(11)V –Cd–N(51) O(11)V –Cd–N(62) O(12)–Cd–O(51)VI O(12)–Cd–O(52)VI O(12)–Cd–N(51)

94.8(2) 110.4(2) 83.3(2) 88.2(2) 155.7(2) 127.8(2) 85.3(3) 107.7(2)

I5x, 1 1 y, z II51 2 x, ]12 1 y, 1 2 z III52 2 x, y 2 ]12 , 1 2 z

3.2. Ternary complexes

3.2.1. [ Cu( bipy)(tsgluO)] The electronic spectrum of this adduct shows a d–d band envelope resolved into two bands at 15 750, 13 700 cm 21 and an isotropic ESR with giso 52.11. The position of the d–d bands can be accounted for by a distorted square-pyramidal geometry as commonly found in Cu II bipy adducts of carboxylate ligands [27].

Zn–Ow(1) Zn–Ow(2)

1.967(9) 2.013(9)

O(51)I –Zn–Ow(1) O(51)I –Zn–Ow(2) Ow(1)–Zn–Ow(2)

112.5(3) 113.4(4) 105.1(4)

Cd(2)–O(112)II Cd(2)–O(151) Cd(2)–O(212) Cd(2)–O(251)IV Cd(2)–Ow(2) Cd(2)–Ow(3)

2.315(7) 2.281(7) 2.257(9) 2.240(7) 2.293(9) 2.350(7)

O(112)II –Cd(2)–O(151) O(112)II –Cd(2)–O(212) O(112)II –Cd(2)–O(251)IV O(112)II –Cd(2)–Ow(2) O(112)II –Cd(2)–Ow(3) O(151)–Cd(2)–O(212) O(151)–Cd(2)–O(251)IV O(151)–Cd(2)–Ow(2) O(151)–Cd(2)–Ow(3) O(212)–Cd(2)–O(251)IV O(212)–Cd(2)–Ow(2) O(212)–Cd(2)–Ow(3) O(251)IV –Cd(2)–Ow(2) O(251)IV –Cd(2)–Ow(3) Ow(2)–Cd(2)–Ow(3)

Cd–O(52)VI Cd–N(51) Cd–N(62)

84.0(3) 92.0(3) 104.2(2) 90.8(3) 172.5(3) 92.8(3) 94.7(2) 168.9(3) 98.6(3) 162.8(3) 97.2(3) 80.8(3) 77.1(3) 82.7(3) 87.9(3)

2.286(7) 2.391(6) 2.352(5)

O(12)–Cd–N(62) O(51)VI –Cd–O(52)VI O(51)VI –Cd–N(51) O(51)VI –Cd–N(62) O(52)VI –Cd–N(51) O(52)VI –Cd–N(62) N(51)–Cd–N(62)

82.9(2) 55.0(2) 117.7(2) 89.5(2) 165.1(2) 120.5(2) 69.7(2)

IV51 2 x, y 2 ]12 , 1 2 z V5x, y 2 1, z VI5 ]12 2 x, y 2 ]12 , 1 2 z

3.2.2. Crystal structure of [ Cd( bipy)(tsgluO)] (3) A drawing showing the labeling scheme is given in Fig. 4; selected bond distances and angles are reported in Table 2. The Cd II atom presents a distorted octahedral geometry due to the coordination of 2,29-bipyridine nitrogens and four oxygen atoms from three different tsgluO 22 entities. The a-carboxyl shows a bidentate bridging coordination mode as observed in the analogous binary complex, and g-carboxyl coordinates as bidentate chelate group.

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

1980

Fig. 2.

ORTEP

view of 2 with the atomic numbering scheme. The hydrogen atoms, except that bound to the chiral carbon atom, are omitted for clarity.

The coordination mode of tsgluO 22 gives rise to a polymeric ribbon extended along the b-axis formed by the repetition of symmetry-generated [Cd(bipy)(tsgluO)] 2 dimers, as shown in Fig. 5. The Cd–O distances are comparable with those of the binary complex and the distortion from regular octahedron is ascribed to the chelation of g-carboxyl and bipy molecule forcing the O(51)–Cd–O(52) and N(51)–Cd– N(62) angles to 55.0(2) and 69.7(2)8, respectively, and the trans O(12)–Cd–O(51)VI angle to 127.8(2). The Cd–N bipy distances are in the range observed for other Cd–bipy adducts of ArSO 2 -amino acids [28]. Bond distance and angles within the tsgluO 22 are

normal and similar to the corresponding values in binary Zn II and Cd II complexes. The C–O distances of each carboxyl group are similar to one another in view of the bidentate binding mode of both carboxyl groups. The 2,29-bipyridine molecule is planar with an angle between the pyridine planes of 1.58 and nearly orthogonal (84.68) with respect to the tsgluO 22 phenyl ring. Bond distances and angles within 2,29-bipyridine are in the range of results from the literature data [28]. The crystal packing is mainly due to the contacts among carbons of phenyl ˚ rings, in the range 3.5–4.0 A. The structures of Cd II -N-p-tolylsulfonyl-L-glutamate complexes confirm that upon the substitution of the Ar-

Fig. 3. Projection showing the polymeric trend of compound 2 on the [100] direction.

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

Fig. 4.

ORTEP

1981

view of 3 with the atom numbering scheme. Hydrogen atoms, except that bound to the chiral carbon atom, are omitted for clarity.

SO 2 -group on the amino nitrogen both the carboxyl groups are active binding sites and the preference of Cd II toward high coordination numbers leads the carboxyl groups to the bidentate coordination. In particular, the bidentate bridging binding mode seems to be preferred by a-carboxylate species.

3.3. Infrared spectroscopy The more relevant IR bands are reported as supplementary data. The infrared spectra of all the complexes, except Cu(tsgluO)?H 2 O, show a series of intense bands in the spectral region of n (COO) as in line with the presence of the two ionized carboxylate groups. In the spectrum of K[Cu(tsgluN,O)]?3H 2 O the disappearance of n (NH) and the shift of antisymmetric and symmetric n (SO 2 ) toward low energy gives further support to the proposed formula, with the N-p-tolylsulfonyl-L-glutamate anion in the trianionic form.

Supplementary data

Fig. 5. Projection showing the trend of the polymeric ribbon of compound 3 on the [010] direction.

Supplementary crystallographic data are available from the CCDC, 12 Union Road, Cambridge CB2 1EZ, UK on request, deposition number: CCDC 112265. IR spectroscopic data are available from the authors.

1982

A. Bonamartini Corradi et al. / Polyhedron 18 (1999) 1975 – 1982

Acknowledgements We are grateful to the Centro Interdipartimentale Grandi Strumenti (CIGS) of the University of Modena, which supplied the Siemens M18X P4 / RA diffractometer and the FT-IR instrument, and the Ministero dell’Universita` e della Ricerca Scientifica of Italy (MURST progetti cofinanziamento) for financial support.

References [1] A.C. Evans, R. Guevremont, D. Rabenstein, Met. Ions Biol. Systems 9 (1979) 41, and references therein. [2] L. Antolini, L.P. Battaglia, A. Bonamartini Corradi, G. Marcotrigiano, L. Menabue, G.C. Pellacani, M. Saladini, M. Sola, Inorg. Chem 26 (1986) 2901, and references therein. [3] G.C. Gramaccioli, R.E. Marsh, Acta Crystallogr. 21 (1966) 594. [4] L. Antolini, G. Marcotrigiano, L. Menabue, G.C. Pellacani, Inorg. Chem. 22 (1983) 141. [5] L. Antolini, G. Marcotrigiano, L. Menabue, G.C. Pellacani, M. Saladini, M. Sola, Inorg. Chem. 24 (1985) 3621. [6] L. Antolini, G. Marcotrigiano, L. Menabue, G.C. Pellacani, M. Saladini, Inorg. Chem. 21 (1982) 2263. [7] G. Battistuzzi, M. Borsari, L. Menabue, M. Saladini, M. Sola, Inorg. Chem. 35 (1996) 4239, and references therein. [8] A. Bonamartini Corradi, E. Gozzoli, L. Menabue, M. Saladini, L.P. Battaglia, P. Sgarabotto, J. Chem. Soc., Dalton Trans. (1994) 273. [9] G. Battistuzzi Gavioli, M. Borsari, L. Menabue, M. Saladini, M. Sola, L.P. Battaglia, A. Bonamartini Corradi, G. Pelosi, J. Chem. Soc., Dalton Trans. (1990) 97.

[10] A. Bonamartini Corradi, L. Menabue, M. Saladini, M. Sola, L.P. Battaglia, J. Chem. Soc., Dalton Trans. (1992) 2623. [11] G. Battistuzzi Gavioli, M. Borsari, L. Menabue, M. Saladini, M. Sola, Inorg. Chem. 30 (1991) 498. [12] L. Antolini, L.P. Battaglia, A. Bonamartini Corradi, G. Marcotrigiano, L. Menabue, G.C. Pellacani, J. Am. Chem. Soc. 107 (1985) 1369. [13] M. Borsari, L. Menabue, M. Saladini, J. Chem. Soc., Dalton Trans. (1996) 4201. [14] G. Battistuzzi Gavioli, M. Borsari, L. Menabue, M. Saladini, M. Sola, J. Chem. Soc., Dalton Trans. (1991) 2961. [15] N. Walker, D. Stuart, Acta Crystallogr. Sect A 39 (1983) 158. [16] A.C.T. North, D.C. Phillips, F.S. Matthews, Acta Crystallogr. Sect. A 24 (1968) 351. [17] G.M. Sheldrick, SHELX86 Program For the Solution of Crystal Structure Determination, University of Gottingen, Germany, 1986. [18] G.M. Sheldrick, SHELX76 Program For the Solution of Crystal Structure Determination, University of Cambridge, UK, 1976. [19] M. Nardelli, Comp. Chem. 7 (1983) 95. [20] C. Rizzoli, V. Sangermano, G. Calestani, G.D. Andreetti, J. Appl. Crystallogr. 20 (1987) 436. [21] C.K. Johnson, ORTEP Report RNL-3794, Oak Ridge National Laboratory, Oak Ridge, TN, 1965. [22] L. Dubicki, R.L. Martin, Inorg. Chem. 5 (1966) 2203. [23] B.J. Hathaway, D.E. Billing, Coord. Chem. Rev. 5 (1970) 143. [24] L. Pauling, 3rd ed, The Nature of Chemical Bond, Cornell University Press, 1960. [25] A. Bondi, J. Phys. Chem. 68 (1964) 441. [26] L. Menabue, M. Saladini, Acta Crystallogr. C50 (1994) 887. [27] L.P. Battaglia, A. Bonamartini Corradi, L. Menabue, M. Saladini, M. Sola, J. Chem. Soc., Dalton Trans. (1987) 1333. [28] M. Saladini, J. Crystallogr. Spectr. Res 23 (1993) 551, and references therein.