Crystal structure of hexaaquacobalt(II) bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate, [Co(H2O)6][C7H5O3SO3]2 · 2H2O

C14H26C0O20S2, triclinic, PI (no. 2), a = 7.048(1) Ä, b = 7.149(1) A, c = 13.733(2) A, a = 90.73(1)°, β = 90.55(1)°, γ = 118.79(1)°, V= 606.3 A, Z= 1, Rgt(F) = 0.025, wR^F) = 0.070, T= 293 K. Source of material A mixture of 5-sulfosalicylic acid dihydrate and C0SO4 · 7H2O (2:1 molar ratio) in 50 ml ethanol/water (1:1 v/v) was heated to boiling point and stirred for two hours. A pink phase being microcrystalline precipitates immediately. After two days, single pink crystals were grown by slow evaporation from aqueous solution at room temperature. Discussion The isolated compound, hexaaquacobalt(II) 3-carboxy-4-hydroxybenzensulfonate dihydrate, consists of a hexaaquacobalt(II) cation, the 3-carboxy-4-hydroxybenzensulfonate anion and water molecules (figure, top). Its main features are similar to those of the isostructural compound of [Cu(H20)6](C706H5S)2 · 2H2O [ 1 ], but there are some slight differences which will be discussed. The Co atom is located on an inversion center and is octahedrally coordinated by six water molecules, while all other atoms are in general positions. The (C7O6H5S) is not coordinated to cobalt, but there are important hydrogen bonds joining cation and anion. The Co ionic radius of 0.72 A is slightly shorter than that of Cu, so we notice a light octahedral distortion with regard to the isostructural copper compound [1]. Due to the Jahn-Teller effect, the Col—03 distance of 2.062(2) Ä is much shorter than those forCol—Ol and Col—02(2.101(1) A, 2.112(1) A, respectively). The Co—Ο distances and O-Co-O angles are comparable with those found in [Co(H20)6](C7H503SC>3)2 · 4H20 [2] or Na2[Co(H20)6](CioH408)2 • 4H20 [3]. The title structure is an alternate stacking of layers of hexaaquacobalt(II) cations and organosulfonate anions. The phenyl rings of the anions are approximately perpendicular to the b,c plane. Within the sulfonate layer, the sulfite groups of every two closest organic molecules pointing in opposite direction along the S1-04 connection (figure, bottom). This packing affords the formation of a short almost linear O-H—Osuifonate hydrogen bond involving each water Η atom. The Ο—Ο distances range from 2.624(3) A to 2.856(2) A, the O-H-O angles from 148(3)° to 179(3)°. The conformation of the sulfonate anion is similar to that of the 2-aminotoluene-4-sulfonate ion in [4], the only difference is due to the substitution of the phenyl ring. Table 1. Data collection and handling. Crystal: Wavelength: μ· Diffractometer, scan mode: APi/Vasured, N(hklUnique: Criterion for /obs, N(hkl)gc. N(param}teSatd: Programs: pink parallelepiped, size 0.6 χ 0.8 χ 0.8 mm Mo Ka radiation (0.71073 A) 9.73 cm" Enraf-Nonius CAD4, ω/20 53.94° 3273,2633 /obs>2<r(W, 1939 222 SHELXS-97 [5], SHELXL-97 [6], DIAMOND [7] Table 2. Atomic coordinates and displacement parameters (in Ä). * Correspondence author (e-mail: tahar.jouini@fstmu.tn) Atom Site X y ζ Uis0 H(l) 2 i 0.338(4) 0.311(4) 0.258(2) 0.050(6) H(2) 2i 0.828(3) 0.334(3) 0.420(1) 0.032(5) H(3) 2 i 0.127(4) 0.212(3) 0.392(2) 0.042(6) H(4) 2/ 0.363(4) -0.280(4) 0.186(2) 0.064(8) H(5) 21 0.279(4) 0.166(4) 0.610(2) 0.051(7) H(6) 2 1 0.479(5) -0.245(5) 0.118(2) 0.07(1) H(7) 2i 0.897(4) 0.279(4) 0.643(2) 0.064(8) H(8) 2 i 0.128(4) -0.052(4) -0.167(2) 0.054(7) H(9) 2/ 0.113(4) 0.133(5) -0.175(2) 0.065(8) H(10) 2j 0.294(5) -0.080(5) 0.074(2) 0.071(9) H(ll) 2i 0.199(4) 0.422(4) -0.033(2) 0.064(8) H(12) 2i 0.168(5) 0.398(5) 0.060(2) 0.070(9) H(13) 2 i 0.376(5) 0.123(5) 0.077(2) 0.055(7) 184 [ C O ( H 2 0 ) 6 ] [ C 7 H 5 0 3 S 0 3 ] 2 · 2 H 2 0 Table 3. Atomic coordinates and displacement parameters (in Ä). Atom Site X y ζ U ii U22 t/33 I/12 U13 i/23 Co(l) 1 a 0 0 0 0.0279(2) 0.0235(2) 0.0220(2) 0.0119(1) -0.0017(1) 0.0002(1) 0(1) 2i 0.1429(2) 0.0550(2) -0.1386(1) 0.0542(8) 0.0360(7) 0.0272(6) 0.0285(6) 0.0037(5) 0.0030(5) CK2) 2i 0.1287(3) 0.3324(2) 0.0140(1) 0.069(1) 0.0255(6) 0.0298(7) 0.0153(6) 0.0004<6) -0.0012(5) 0(3) 2i 0.2812(2) 0.0216(3) 0.0578(1) 0.0372(7) 0.0346(7) 0.0619(9) 0.0146(6) -0.0202(7) -0.0019(7) S(l) 2i 0.7855(1) 0.4234(1) 0.2254(1) 0.0316(2) 0.0256(2) 0.0207(2) 0.0108(2) -0.0011(1) 0.0005(1) CK4) 2i 0.9270(2) 0.6545(2) 0.2425(1) 0.0338(6) 0.0265(6) 0.0284(6) 0.0094(5) -0.0037(5) 0.0038(4) 0(5) 2i 0.9113(2) 0.3113(2) 0.2281(1) 0.0518(8) 0.0409(7) 0.0412(7) 0.0286(6) 0.0094(6) 0.0005(6) 0(6) 2i 0.6533(2) 0.3840(2) 0.1373(1) 0.0418(7) 0.0445(7) 0.0240(6) 0.0048(6) -0.0077(5) 0.0018(5) C(l) 2i 0.6067(3) 0.3323(2) 0.3245(1) 0.0292(8) 0.0215(7) 0.0251(7) 0.0102(6) 0.0002(6) 0.0019(5) C(2) 2/ 0.3938(3) 0.2971(3) 0.3164(1) 0.0331(8) 0.0307(8) 0.0308(8) 0.0145(7) -0.0070(6) 0.0011(6) C(3) 2i 0.6870(3) 0.3096(2) 0.4132(1) 0.0251(7) 0.0240(7) 0.0279(7) 0.0103(6) -0.0012(6) 0.0016(6) C(4) 2i 0.2638(3) 0.2393(3) 0.3970(1) 0.0260(8) 0.0366(9) 0.0413(9) 0.0149(7) -0.0035(7) 0.0000(7) C(5) 2i 0.5588(3) 0.2554(2) 0.4957(1) 0.0292(8) 0.0200(7) 0.0253(7) 0.0097(6) -0.0016(6) 0.0002(5) C(6) 2i 0.3443(3) 0.2193(3) 0.4876(1) 0.0286(8) 0.0257(7) 0.0317(8) 0.0100(6) 0.0035(6) -0.0005(6) C(7) 2i 0.6487(3) 0.2440(2) 0.5918(1) 0.0335(8) 0.0207(7) 0.0270(8) 0.0083(6) -0.0024(6) 0.0006(6) 0(7) 2i 0.2126(2) 0.1671(3) 0.5644(1) 0.0343(7) 0.0602(9) 0.0366(7) 0.0192(7) 0.0079(6) 0.0008(6) 0(8) 2i 0.5466(2) 0.2079(2) 0.6673(1) 0.0456(7) 0.0463(7) 0.0250(6) 0.0159(6) 0.0017(5) 0.0034(5) 0(9) 2i 0.8492(2) 0.2780(2) 0.5882(1) 0.0352(7) 0.0480(7) 0.0296(6) 0.0172(6) -0.0067(5) 0.0052(5) 0(10) 2i 0.3686(3) -0.2900(3) 0.1285(1) 0.0401(8) 0.0539(9) 0.0311(7) 0.0213(7) -0.0024(6) -0.0046(6)