Synthesis and structures of two molybdenum(VI) complexes derived from similar benzohydrazone ligands with catalytic properties

Two new structurally similar molybdenum(VI) complexes, [MoO₂L¹(CH₃OH)] (1) and [MoO₂L²(CH₃OH)] (2), where L¹ is the dianionic form of N′-(2-hydroxy-5-nitrobenzylidene)-2-methylbenzohydrazide and L² is the dianionic form of N′-(2-hydroxy-4-methoxybenzylidene)-2-methylbenzohydrazide, were prepared and structurally characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P2₁/c, with unit cell dimensions a?=?7.941(1), b?=?14.337(2), c?=?15.141(2)?Å, β?=?92.782(2)°, V?=?1721.8(4)?ų, Z?=?4, R₁?=?0.0286, wR₂?=?0.0650, GOOF?=?1.028. 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a?=?8.003(1), b?=?10.608(1), c?=?10.880(1)?Å, α?=?95.745(2)°, β?=?97.627(2)°, γ?=?105.762(2)°, V?=?872.0(2)?ų, Z?=?2, R₁?=?0.0226, wR₂?=?0.0595, GOOF?=?1.116. X-ray analysis indicates that Mo in the complexes are coordinated by the phenolate oxygen, imino nitrogen, and enolate oxygen of the benzohydrazone, methanol, and two oxo groups, generating octahedral coordination. The oxidation of olefins with the complexes as catalysts was evaluated, indicating that the complexes showed excellent catalytic efficiency in oxidation of most aliphatic and aromatic substrates under mild conditions using tert-butyl hydrogen peroxide as oxidant.     

Comment on the section: “Antioxidant measurements and hydroxyl radical scavenging activity” in synthesis,characterization, DNA binding,and antioxidant activities of four copper(II) complexes containing N-(3-hydroxybenzyl)-amino amide ligands,by Zhi Li-Hua,Wu Wei-Na,Wang Yuan,Sun Guang,J. Coord. Chem., 66, 227 (2013)

Two structurally similar vanadium(V) complexes, [VOL¹L] (1) and [VOL²L] (2), where L¹ is the dianionic form of N′-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide, L² is the dianionic form of N′-(3,5-dibromo-2-hydroxybenzylidene)nicotinohydrazide, and L is benzohydroxamate, were prepared and characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P2₁/c, with unit cell dimensions a?=?12.0262(7), b?=?16.5629(9), c?=?12.3449(8)?Å, β?=?105.160(2)°, V?=?2373.4(2)?ų, Z?=?4, R₁?=?0.0376, wR₂?=?0.0844, GOOF?=?1.058; 2 crystallizes in the monoclinic space group P2₁/c, with unit cell dimensions a?=?10.6439(7), b?=?16.1968(9), c?=?13.1108(8)?Å, β?=?104.180(2)°, V?=?2191.4(2)?ų, Z?=?4, R₁?=?0.0521, wR₂?=?0.1142, GOOF?=?1.018. X-ray analysis indicates that vanadium in the complexes are coordinated by phenolate oxygen, imino nitrogen, and enolate oxygen of the hydrazone, two oxygens of the benzohydroxamate, and one oxo, generating octahedral coordination. Oxidations of olefins with the complexes as catalysts were evaluated. The complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant.     

Synthesis,structure, and biological evaluation of three Cu(II) and Ni(II) (E)-3-(3,4-dimethoxyphenyl)acrylate complexes with organic diamines as potential urease inhibitors

Three new complexes (1–3) have been synthesized and characterized by X-ray single crystal determination and evaluated for inhibitory activity on jack bean urease. All the complexes contained a new cinnamic acid derivative as the ligand (C₁₁H₁₂O₄), (E)-3-(3,4-dimethoxyphenyl)acrylic acid, and crystallized in monoclinic C2/c space group. Complex 1 (C₁₁H₁₁O₄)₄(C₃N₂H₈)₂Cu₂ (C₃N₂H₈?=?1,2-diaminopropane) was obtained with a?=?20.488(2), b?=?19.596(2), c?=?15.2500(13), β?=?93.502(2)°, V?=?6111.2(10)?ų, Z?=?4, R ₁ ?=?0.0616, and wR ₂ ?=?0.2059. Complex 2 (C₁₁H₁₁O₄)₄(C₃N₂H₈)₂Cu₂ (C₃N₂H₈=1,3-diaminopropane) was obtained with a?=?20.2494(12), b?=?19.5732(12), c?=?14.8940(8), β?=?96.884(2)°, V?=?5860.6(6)?ų, Z?=?4, R ₁ ?=?0.0409, and wR ₂ ?=?0.1107. Complex 3 (C₁₁H₁₁O₄)₂(C₂N₂H₆)₂Ni₂·H₂O (C₂N₂H₆?=?ethylenediamine) was obtained with a?=?28.359(2), b?=?6.5422(5), c?=?16.8587(14), β?=?101.359(2)°, V?=?3066.5(4)?ų, Z?=?4, R ₁ ?=?0.0422, and wR ₂ ?=?0.1190. It was found that copper(II) complexes 1 [IC₅₀?=?4.71?μM] and 2 [IC₅₀?=?3.15?μM] showed strong inhibitory activity against jack bean urease compared with acetohydroxamic acid [IC₅₀?=?10.01?μM] as a positive reference. Unfortunately, 3 exhibited no inhibitory activity.     

A dimeric luminescent lanthanide complex [Eu(PAA)2(phen)(NO3)]2: hydrothermal synthesis,crystal structure and fluorescence

A lanthanide coordination complex [Eu(PAA)₂(phen)(NO₃)]₂ (PAA?=?phenylacetic acid, phen?=?1,10-phenanthroline) has been synthesized by the hydrothermal method. Single crystal X-ray diffractions show that it forms a dimeric molecular structure. The title complex crystallizes in the triclinic system, space group P 1, with lattice parameters a?=?8.9473(8)?Å, b?=?13.3659(12)?Å, c?=?13.4745(12)?Å, α?=?60.7590(10)°, β?=?89.5100(10)°, γ?=?71.9850(10)°, V?=?1317.3(2)?ų, D _c?= 1.675?Mg?m^?3, Z?=?1, F(000)?=?660, GOF?=?1.003, R ₁?=?0.0206, wR ₂?=?0.0575. The fluorescence excitation and emission spectra have been investigated.     

Hydrothermal synthesis and crystal structure of a new two-dimensional zinc citrate complex

A new two-dimensional compound C₁₂H₁₄O₁₆Zn₃ (1), containing seven-coordinate zinc atoms was prepared by the hydrothermal technique. The compound obtained was characterized by TG-DTA, single crystal X-ray diffraction, elemental analysis and FT-IR analysis. Single-crystal X-ray diffraction analysis shows that compound 1 crystallizes with monoclinic symmetry in the space group P2₁/c, a?=?6.1552(13)?Å, b?=?14.546(3)?Å, c?=?9.581?Å, β?=?102.66(2)°, V?=?836.9(4)?ų, Z?=?2, R1?=?0.0311, wR2?=?0.0830.     

Syntheses,urease inhibition activities,and fluorescent properties of transition metal complexes

Four transition metal complexes with Schiff base and 1,10-phenanthroline, [Cu(L)(phen)]₂·C₂H₅OH (1), [Zn(L)(phen)]₂·C₂H₅OH (2), [Ni(L)(phen)]₂·C₂H₅OH (3), and [Co(L)(phen)]₂·C₂H₅OH (4) (H₂L?=?1-((2-hydroxynaphthalen-1-yl)methylene)thiosemicarbazide; phen?=?1,10-phenanthroline) were synthesized and characterized by physico-chemical methods. The crystal structure of 1 was determined by X-ray single-crystal diffraction analysis. 1 crystallizes in the orthorhombic space group Pbca with a?=?15.008(9), b?=?16.100(10), c?=?37.54(2)?Å, V?=?9070(10)?ų, Z?=?8, GOOF?=?1.002, R ₁?=?0.0626, and wR ₂?=?0.0912. The fluorescence and urease inhibitory activities of the compounds were tested. The enzymatic activity study indicated that 3 possessed potent inhibition against jack bean urease, with IC₅₀?=?1.2?±?0.1?μM, and about 35 times more than 42.1?±?0.4 acetohydroxamic acid as positive reference. This suggests that inhibitory efficiency of these complexes can be strongly influenced by different transition metal ions.     

Synthesis,structure and characterization of copper(II) and zinc(II) complexes based on 3-carboxyl-1,2,4-triazole

Two complexes [CuL₂(H₂O)₂] (1) and [ZnL₂(H₂O)₂] (2) (L?=?3-carboxyl-1,2,4-triazole (L)) have been synthesized and characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/n, a?=?8.632(8)?Å, b?=?9.153(8)?Å, c?=?6.991(7)?Å, β?=?94.279(12)°, Z?=?2, R ₁?=?0.0296, wR ₂?=?0.0918. Compound 2 also crystallizes in the monoclinic space group P ₂(1)/n, a?=?4.937(3)?Å, b?=?18.107(10)?Å, c?=?6.344(4)?Å, β?=?106.839(7)°, Z?=?2, R ₁?=?0.0230, wR ₂?=?0.0556. Extensive intermolecular hydrogen bonds assemble 1 and 2 into three-dimensional (3D) supramolecular architectures, with eight-member H-bonded synthons. Compounds 1 and 2 were also characterized by element analysis, FT–IR, luminescence and EPR studies.     

Syntheses,crystal structures,and antimicrobial activities of nickel(II) and cadmium(II) complexes with 4-methylsulfonyl cinnamate and diamines

Two metal complexes, [Ni^II(mscinn)₂(pda)₂] (1) and [Cd^II(mscinn)₂(dmeda)₂·2H₂O] (2) (mscinn?=?4-methylsulfonyl cinnamate, pda?=?propane-1,3-diamine, dmeda?=?N′,N′-dimethylethane-1,2-diamine), were synthesized by reacting 4-methylsulfonyl cinnamate with the diamines and metal salts. Their structures were determined by single-crystal X-ray diffraction analysis. Crystal parameters of 1: C₂₆H₃₈N₄NiO₈S₂, M?=?657.43, monoclinic, P2₁/c, a?=?16.6123(8)?Å, b?=?8.5956(4)?Å, c?=?11.2047(5)?Å, β?=?107.423(1)°, V?=?1526.54(12)?ų, Z?=?2, D _calcd?=?1.430?g?cm^?3, F(000)?=?692, μ?=?0.825?mm^?1, R ₁?=?0.0257, wR ₂?=?0.0669. Crystal data of 2: C₂₈H₄₂CdN₄O₈S_2?·?2(H₂O), M?=?775.24, monoclinic, P2₁/c, a?=?9.8278(4)?Å, b?=?11.6611(5)?Å, c?=?15.3972(7)?Å, β?=?96.195(1)°, V?=?1754.26(13)?ų, Z?=?2, D _calcd?=?1.468?g?cm^?3, F(000)?=?804, μ?=?0.798?mm^?1, R ₁?=?0.0299, wR ₂?=?0.0770. Antimicrobial activities for 1 and 2 against Escherichia coli, Pseudomonas putida, Bacillus subtilis, and Bacillus cereus had better antibacterial activity than their parent carboxylic acid against Gram-positive bacteria (B. subtilis and B. cereus). The cadmium complex of the cinnamate displayed high inhibitory activity with an MIC value of 5?µg?mL^?1 against P. putida, while the nickel complex also exhibited good inhibitory potency with an MIC value of 5?µg?mL^?1 against B. subtilis.     

Hydrothermal syntheses,crystal structures,and thermal stability of two new 3D open-framework metal(II) phosphonates

This article reports the hydrothermal synthesis and characterization of two new phosphonate compounds NaCo[O₃PCH(OH)CO₂] (1) and NaMn[O₃PCH(OH)CO₂] (2) based on 2-hydroxyphosphonoacetic acid (H₃L). Their structures have been characterized by single-crystal X-ray diffraction as well as with elemental analysis, infrared spectroscopy and thermogravimetric analysis. The two isomorphous compounds crystalline in the orthorhombic, space group Pbca: Crystal data for 1: a?=?10.1827(8)?Å, b?=?9.6673(8)?Å, c?=?10.7853(9)?Å, V?=?1061.70(15)?ų, Z?=?8, R ₁?=?0.0252, wR ₂?=?0.0577; Crystal data for 2: a?=?10.4309(18)?Å, b?=?9.7913(17)?Å, c?=?10.9012(19)?Å, V?=?1113.4(3)?ų, Z?=?8, R ₁?=?0.0194, wR ₂?=?0.0536. In the two compounds, the metal atoms are octahedrally coordinated; all oxygen atoms from the H₃L ligand are involved in coordination. The overall structures can be described as a 3D open framework with channels running along the a axis and the charge-compensating Na⁺ cations being located at the intersections of these channels.     

A 1D coordination polymer {Pb[C6H4(COO)2][phen]} n with strong blue fluorescent emission

The hydrothermal reaction of 1,3-dicyanobenzene, 1,10-phenanthroline (phen) and Pb(CH₃COO)₂ yields a new 1D coordination polymer, {Pb[C₆H₄(COO)₂][phen]} _n . The 1,3-benzenecarboxylate anion found in the final product was generated in situ during the synthesis by hydrolysis of 1,3-dicyanobenzene. X-ray diffraction shows that complex 1 crystallizes in the triclinic system, space group P 1, a?=?7.5442(2)?Å, b?=?9.7962(3)?Å, c?=?13.1505(4)?Å, α?=?69.739(2)?Å, β?=?80.597(2)?Å, γ?=?71.377(2)?Å, v?=?862.48(4)?ų, Z?=?2, D _c?=?2.124 Mg?m^?3. Complex 1 emits strong blue fluorescent light (λem(max)?=?482.4?nm) when excited by UV light in the solid state at room temperature.     

Hydrothermal synthesis and characterization of two new arsenic–vanadate compounds with the same cluster anion [As8V14O42(H2O)]4−

Two new arsenic–vanadate compounds [Co(C₄H₁₃N₃)₂]₂[As₈V₁₄O₄₂(H₂O)]?·?3.5H₂O (1) and (C₂N₂H₉)₂(C₂N₂H₁₀)[As₈V₁₄O₄₂(H₂O)]?·?2.33H₂O (2) have been hydrothermally synthesized and characterized by X-ray single crystal diffraction, IR spectra and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic space group P ₂(1)/c, a?=?24.649(9)?Å, b?=?13.364(5)?Å, c?=?22.463(8)?Å, β?=?104.008(5)°, V?=?7180(5)?ų, Z?=?4, R ₁?=?0.0787, and wR ₂?=?0.1859. Compound 2 crystallizes in rhombohedral system with space group R3c, a?=?b?=?c?=?22.2405(5)?Å, α?=?β?=?γ?=?110.4030(10)°, V?=?8163.4(3)?ų, Z?=?6, R ₁?=?0.0341 and wR ₂?=?0.0941. The structural analyses show that both compounds have the same discrete cluster anion [As₈V₁₄O₄₂(H₂O)]^4?. Moreover, in 1, the polyanions are connected through van der Waals forces to generate soft channels that are filled by [Co(C₄H₁₃N₃)₂]²⁺ cations and water. In 2, water and organic molecules link cluster anions to create the supramolecular assembly through hydrogen bonding.     

Synthesis,structural characterization and biological activity of polyoxometallate-containing protonated amantadine as a cation

A novel isopolyoxomolybdate complex (C₁₀H₁₈N)₄Mo₈O₂₆·6(CH₃)₂SO 1 was synthesized, purified and characterized by means of elemental analysis, IR and ¹H NMR spectra and single-crystal X-ray diffraction. It crystallizes in a triclinic system with a?=?11.5090(6), b?=?12.8399(3), c?=?14.774(13)?Å, α?=?105.390(16), β?=?93.09(4), γ?=?106.100(10)°, V?=?2003.1(2)?ų, Z?=?2, R1?=?0.0789, wR2?=?0.2190. Complex 1 is constructed from [Mo₈O₂₆]^4?, (C₁₀H₁₈N)⁺ and (CH₃)₂SO and extends to form a two-dimensional network via hydrogen bonds and weak interactions in the ab plane. Chicken embryo experiments show that Compound 1 has high antiviral activity in vitro.     

An ion-pair complex [TTF][Pd(mnt)2]: synthesis,crystal structure,magnetic property,and electrical conductivity

A new ion-pair complex, [TTF][Pd(mnt)₂] (1), where TTF⁺ =?tetrathiafulvalene and mnt^2??=?maleonitriledithiolate, was synthesized and characterized structurally. Compound 1 crystallizes in triclinic space group P-1, with a?=?8.008(5)?Å, b?=?11.333(8)?Å, c?=?11.373(6)?Å, α?=?108.112(7)°, β?=?91.550(5)°, γ?=?95.232(5)°, and V?=?975.2(11)?ų. The [TTF]⁺ cations (C) and [Pd(mnt)₂]^? anions (A) form mixed stacks in …AACCAACC… fashion, and the neighboring mixed stacks are held together via van der Waals forces in the crystal. Compound 1 shows weak Curie/Weiss-type magnetic behavior from 2 to 370?K; theoretical investigation disclosed the existence of strongly antiferromagnetic coupling in both [Pd(mnt)₂]₂ ^2? and [TTF]₂ ²⁺ dimer pairs via frontier orbitals overlap mechanism and weakly ferromagnetic coupling between the face-to-face overlapped [TTF]⁺ and [Pd(mnt)₂]^? via spin polarization mechanism within a mixed stack. The powdered pellet electrical conductivity measurement indicated that 1 shows semiconductor character with activation energy of 1.1(3)?eV.     

Solid state structures of the chiral heterobimetallic complexes [Cu(dach)2][Pt(CN)4] · 2H2O, [Ni(dach)3][Pt(CN)4] · 2DMF · H2O,and [Pd(dach)2][Pt(CN)4] · H2O (dach = 1 R , 2 R -diaminocyclohexane)

The chiral dinuclear heterometallic complexes [Cu(dach)₂][Pt(CN)₄]?·?2H₂O (1), [Ni(dach)₃][Pt(CN)₄]?·?2DMF?·?H₂O (2), and [Pd(dach)₄][Pt(CN)₄]?·?H₂O (3) (dach?=?1R,2R-cyclohexanediamine) have been prepared and characterized by X-ray diffraction analysis. Crystal data: 1, monoclinic, P2₁, a?=?8.108(3), b?=?15.552(6), c?=?9.914(4)?Å, β?=?110.931(6)°, V?=?1167.6(8)?ų, Z?=?2, R ₁?=?0.0420, wR ₂?=?0.1122; 2, monoclinic, P2₁, a?=?13.264(11), b?=?9.285(7), c?=?16.211(13)?Å, β?=?111.640(9)°, V?=?1856(3)?ų, Z?=?2, R ₁?=?0.0276, wR ₂?=?0.0698; 3, monoclinic, P2₁, a?=?6.887(2), b?=?12.809(4), c?=?12.975(4)?Å, β?=?94.865(4)°, V?=?1140.6(6)?ų, Z?=?2, R ₁?=?0.057, wR ₂?=?0.156. In complex 1, the Pt and Cu atoms are linked by a CN bridge that presents a very bent C=N–Cu angle [136.8(8)°].     

Synthesis,crystal structures and fluorescence of cadmium(II) coordination polymers with derivatives of pyrazine-1,4-dioxide and thiocyanate as mixed-bridging ligands

Two Cd(II) coordination polymers have been synthesized with derivatives of pyrazine-1,4-dioxide and thiocyanate anion as bridging ligands and structurally determined by X-ray crystallography. Complex 1, [Cd(μ_1,3-SCN^?)₂(μ_1,6-L1)] _n (L1?=?2,5-dimethylpyrazine-1,4-dioxide), belongs to the triclinic, space group P 1 with a?=?5.7627(18)?Å, b?=?7.182(2)?Å, c?=?7.509(2)?Å, α?=?74.042(3)°, β?=?84.766(4)°, γ?=?88.162(4)°; complex 2, [Cd₂(μ_1,3-SCN^?)₄(μ₄-L2)] _n (L2?=?2,3,5,6-tetramethylpyrazine-1,4-dioxide), crystallizes in a monoclinic system with space group C2/m with a?=?10.194(4)?Å, b?=?13.491(6)?Å, c?=?8.140(3)?Å, β?=?120.372(4)°. Complex 1 shows a two-dimensional sheet structure, and in a direction the Cd(II) ions were coordinated by μ_1,3-SCN^? forming the one-dimensional chain and the L1 bridging ligand made the chains connect in the c direction leading to formation of a two-dimensional sheet on the ac plane. For 2 the one-dimensional chains in the a axis were constructed by coordination of μ_1,3-SCN^? bridging ligands with the Cd(II) ions, and in b and c directions the chains were joined by L2 bridging ligands leading to a three-dimensional structure. In 2 L2 displays a μ₄-bridging coordination mode. Both complexes exhibit strong fluorescence emission.     

Syntheses,structures, and spectroscopic properties of copper(II) and cobalt(III) complexes containing 1,4,7-tribenzyl-1,4,7-triazacyclononane ligand

Three new complexes [CuL(N₃)₂] (1), [CuL(SCN)₂] (2), and [CoL(SCN)₃] (3) (L?=?1,4,7-tribenzyl-1,4,7-triazacyclononane) have been synthesized and structurally characterized. Complex 1 crystallizes in monoclinic space group P2(1)/n with unit cell parameters a?=?14.105(7), b?=?8.999(5), c?=?21.603(11)?Å, β?=?100.470(7)°. While 2 crystallizes in triclinic space group P-1 with unit cell parameters a?=?9.6380(16), b?=?10.6993(18), c?=?15.798(3)?Å, α?=?106.636(3), γ?=?116.478(3)°. Complex 3 crystallizes in trigonal space group P–3c1 with unit cell parameters a?=?14.744(3), b?=?14.744(3), c?=?16.098(4)?Å, γ?=?120°. Elemental analysis, IR, UV-vis spectra of complexes 1–3 and ESR spectra of complexes 1–2 were also determined.     

Unusual coordination features and self-assembly of a crown ether complex [Na2(2,3-naphtho-15-crown-5)2(NO3)][Cu(NO3)3(H2O)]

A novel supramolecular complex, [Na₂(2,3-naphtho-15-crown-5)₂(NO₃)][Cu(NO₃)₃(H₂O)] (1), has been prepared and characterized by X-ray single crystal diffraction. The complex crystallizes in the triclinic system, space group Pī, with a?=?11.233(6), b?=?13.342(7), c?=?16.601(8)?Å, α?=?89.836(7), β?=?79.132(8), γ?=?66.545(7)°, V?=?2234(2)?ų, Z?=?2 and final R ₁(wR ₂)?=?0.0467(0.1164). Novel coordination features and supramolecular architectures are found in the solid state of 1. Two [Na(2,3-naphtho-15-crown-5)]⁺ cations containing two different sodium coordination numbers (six and seven) are bridged by a tridentate nitrate group, to form a larger complex cation, [Na₂(2,3-naphtho-15-crown-5)₂(NO₃)], which is assembled into a novel 1D zigzag chain-like structure through aromatic C–H?···?π interactions.     

Synthesis,characterization and crystal structures of two alkaline-earth metal complexes of olsalazine

Two one-dimensional linear coordination polymers, [Mg(L)?·?4(H₂O)] (H₂L?=?olsalazine) and 2 [Ca(L)?·?4(H₂O)] were obtained from self-assembly of CaCl₂ or MgSO₄ with olsalazine and their structures determined by single crystal X-ray diffraction. Both complexes are one-dimensional polymers, for complex 1 with crystal data: P2(1)/c, a?=?9.5224(18), b?=?11.309(2), c?=?16.211(3)?Å, β?=?106.648(3)°, V?=?1672.6(6)?ų, Z?=?4, R ₁?=?0.0695, wR ₂?=?0.2183, for complex 2 with crystal data: P4(3)2(1)2, a?=?10.4006(2), b?=?10.4006(2), c?=?32.0746(10)?Å, V?=?3469.59(14)?ų, Z?=?8, R ₁?=?0.0332, wR ₂?=?0.1015. In the complexes, Mg and Ca adopt totally different coordination modes. Alkaline-earth Mg is six-coordinate octahedronal geometry, however, in 2, the local coordination geometry around calcium atom can be best described as a slightly distorted pentagonal bipyramid crystallizing in a homo-chiral space group. Olsalazine in both compounds also adopts dissimilar coordination modes.