Two 1-D metal-organic polymers constructed from bis-benzimidazole-based ligands: syntheses,crystal structures,and luminescent properties

By combination of Mn(II) and Hg(II) salts with a flexible building unit 1,1′-(1, 5-pentanediyl)bis-1H-benzimidazole (pbbm), two 1-D chain metal-organic polymers [Mn(SCN)₂(pbbm)₂] _n (1) and {[HgCl₂(pbbm)] · DMF} _n (2) have been prepared. The polymeric 1-D chains in 1 consist of parallel ribbons of rings, whereas 2 possesses a 1-D zig-zag chain framework based on tetrahedral mercury atoms bridged by pbbm molecules and terminally coordinated by two chlorides. The significant differences of these metal-organic frameworks indicate that the flexible pbbm ligand adjusts its conformation to meet the requirement of the coordination preference of the metal center. The photoluminescent properties of these new materials have been studied in the solid state at room temperature.     

Mercury(II) complexes of pyrrolidinedithiocarbamate,crystal structure of bis{[μ2-(pyrrolidinedithiocarbamato-S,S ′)(pyrrolidinedithiocarbamato-S,S ′)mercury(II)]}

Mercury(II) complexes of pyrrolidinedithiocarbamate (PDTC) having the general formula [Hg(PDTC)X] (X = Cl^?, SCN^?, and CN^?) and [Hg(PDTC)₂] have been prepared and characterized by elemental analysis, IR, and NMR. The crystal structure of [Hg(PDTC)₂] has also been determined by X-ray crystallography, showing that the complex is a centrosymmetric dimer, [Hg₂(PDTC)₄] (bis[µ²-(pyrrolidinedithiocarbamato-S,S′)(pyrrolidinedithiocarbamato-S,S′)mercury(II)]) (1). The solid-state structure of 1 contains two crystallographically equivalent Hg(II) centers in a distorted tetrahedron.     

Synthesis,structure and electrochemical properties of a zinc(II) coordination polymer based on ferrocenyl-substituted carboxylate and bis (benzimidazolyl)pentane ligands

By reaction of two ligands, Na(o-OOCC₆H₄COFc) (Fc?=?(η⁵–C₅H₅)Fe(η⁵–C₅H₄)) and 1,1′–(1,5–pentamethylene)bis-1H-benzimidazole (pbbm), with Zn(OAc)₂?·?2H₂O in methanol solution, we have synthesized a zinc(II) coordination polymer [Zn(o-OOCC₆H₄COFc)₂(pbbm)] _n . The polymer was characterized by X-ray single crystal diffraction, IR spectroscopy, and elemental analysis. Each Zn atom was connected by two pbbm ligands, leading to an infinite one-dimensional chain. Two monodentate o-FcCOC₆H₄COO^? anions completed the coordination sphere of the central Zn(II) ion. The polymer's electrochemical properties were investigated in DMF solution.     

Cobalt (II) coordination polymers based on 3,5-dinitrobenzoate and flexible bis(benzimidazole) derivatives bearing different spacer lengths and substituents

Three new Co^II coordination polymers, namely [Co(DNBA)₂(pbdmbm)] (1), [Co₂(H₂O)₂(DNBA)₂(ebdmbm)₂] (2) and [Co₂(DNBA)₂(pbbm)₂] (3) have been obtained by hydrothermal reactions of Co^II with flexible bis(benzimidazole) ligands [1,1′-(1,3-propanediyl)bis(5,6-dimethylbenzimidazole) (pbdmbm), 1,1′-(1,2-ethanediyl)bis(5,6-dimethylbenzimidazole) (ebdmbm), 1,1′-(1,3-propanediyl)bis(benzimidazole) (pbbm)] plus 3,5-dinitrobenzoic acid (HDNBA). The complexes have been characterized by single crystal X-ray diffraction, elemental analyses, IR and TG. Complexes 1 and 3 exhibit one-dimensional chains composed of Co^II centers bridged by flexible bis(benzimidazole) ligands. Complex 2 is a three-dimensional NaCl-type supramolecular framework constructed from binuclear units, which are formed by two Co^II centers and two ebdmbm ligands. The spacer length and substituents on the bis(benzimidazole) ligands are crucial for the construction of these structures. The photoluminescence properties of the complexes and the cyclic voltammetry behavior of complex 1 are described.     

Ferrocene-carboxylate coordination complexes bridged by different N-containing ligands

Six new coordination complexes, [Cd(η ²-OOCCH=(CH₃)CFc)₂(bix)]₂·(CH₃OH)_0.5 (1), [Zn(η ²-OOCCH=(CH₃)CFc)(η ¹-OOCCH=(CH₃)CFc)(bix)]₂·(H₂O)_0.5 (2), [Zn(η ²-OOCCH=(CH₃)CFc)₂(pbbm)]₂·(CH₃OH)₂ (3), {[Mn(η ¹-OOCCH=(CH₃)CFc)₂(bbbm)(H₂O)₂]·(CH₃OH)₃}_n (4), {[Cd(η ¹-OOCCH=(CH₃)CFc)₂(bbbm)]·(CH₃OH)₂}_n (5), and [Cd(η ²-OOCCH=(CH₃)CFc)₂(pmbbm)]_n (6) {Fc?=?(η ⁵-C₅H₄)Fe(η ⁵-C₅H₄), bix?=?1,4[bis(imidazol-1-ylmethyl)benzene], pbbm?=?1,1′-[(1,4-propanediyl)bis-1H-benzimidazole], bbbm?=?1,1′-[(1,4-butanediyl)bis-1H-benzimidazole)], pmbbm?=?1,1′-[(1,4-pentanediyl)bis-1H-benzimidazole]}, were prepared and characterized. X-ray crystallographic analysis reveals that 1–3 are dimers bridged by bix and pbbm. Complexes 4–6 are one-dimensional (1-D) structures bridged by bbbm and pmbbm, respectively. Various π–π interactions were discovered in 1–6 that make significant contributions to molecular self-assembly. Solution differential pulse voltammetry of 1–6 indicates that the half-wave potentials of the ferrocenyl moieties in these complexes shift to positive potential compared with that of 3-ferrocenyl-2-crotonic acid.     

Two photoluminescent pentanuclear homo- and hetero-metal complexes based on benzotriazole bridge

Two new discrete Btz-bridged pentanuclear metal complexes, [HDMF][NaHg₄(Btz)₆I₄] (1) and [Zn₅(Btz)₆(L)₃(Ac)]?·?0.5MeOH?·?0.5H₂O (2) (Btz?=?deprotonated benzotriazole, L?=?p-aminobenzoate, HDMF?=?protonated DMF, and Ac?=?acetate), were synthesized using three-layered diffusion and natural evaporation methods, respectively. In 1, the pentanuclear anion [NaHg₄(Btz)₆I₄]^? is composed of a tetrahedral arrangement of four four-coordinate Hg(II) ions centered on the six-coordinate Na(I), and thereby forming a rare Btz-bridged hetero-metal complex. Compound 2 is a neutral pentanuclear homo-metal complex, consisting of a tetrahedral arrangement of four five-coordinate Zn(II) ions centered on the fifth six-coordinate Zn(II). The thermal stabilities and solid-state photoluminescence of the two complexes have been investigated.     

Two copper complexes based on nitronyl nitroxide with different halides: structures and magnetic properties

Complexes based on different halogen-substituted nitronyl nitroxide radicals and Cu(II), Cu₃(hfac)₆(NIT-Ph-F)₂ (1) and Cu₃(hfac)₆(NIT-Ph-Cl)₂ (2) (hfac = hexafluoroacetylacetonate; NIT-Ph-F = 2-(4′-fluorophenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide; NIT-Ph-Cl = 2-(4′-chlorphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were synthesized and characterized structurally and magnetically. X-ray crystal structure analyses show that 1 and 2 have similar centrosymmetric five-spin structures consisting of three Cu(II) ions bridged by two nitroxide ligands. The Cu(II) is coordinated by six oxygens to form an octahedron, while the five coordination of the terminal Cu(II) ion is square pyramidal. Magnetic measurements reveal strong antiferromagnetic interactions between Cu(II) ions and radicals in 1 (J = ?38.9 cm^?1) and weak antiferromagnetic interactions between Cu(II) ions and radicals in 2 (J = ?1.23 cm^?1), which may be explained by the bond length of the Cu–O_rad (2.468(2) Å) in 1, which is shorter than that (2.514(2) Å) in 2, and the dihedral angle (73.17(1)°) of the plane O7–O8–Cu(2)–O7A–O8A with the moiety O5–N1–C11–N2–O6 in 1 is smaller than (77.82(1)°) in 2.     

Dinuclear Zn(II) and Hg(II) complexes of an angular dipyridyl ligand: syntheses,crystal structures,and properties

The angular polytopic dipyridyl ligand 2,6-bis(quinoline-2-carboxamido)pyridine (H₂L) was prepared. Assemblies of H₂L with ZnAc₂ and HgAc₂ resulted in two new dinuclear complexes [Zn₂(L)(Ac)₂]?·?1.5H₂O?·?0.5CH₃OH (1) and [Hg₂(L)(Ac)₂]?·?5H₂O?·?CH₃OH (2) where the doubly deprotonated L^2? bi-chelate as μ-kN,N′?:?kN″,N″′, bridging the two metal centers (Ac?=?acetate). In 1, the two Zn(II) ions are also doubly bridged by two Ac ions in a μ-kO?:?kO′ coordination, and thus each metal center adopts a distorted tetrahedral geometry. In 2, each Ac ion is only terminal to Hg(II), in a rare distorted triangular or T-shaped coordination geometry. Free H₂L, 1, and 2 emit interesting bluish-green fluorescence with strong intensities. Thermogravimetric analysis of 1 shows that the dinuclear structure of 1 is stable to 382°C.     

Syntheses and structures of two NiIICoIINiII complexes of macrocyclic ligands

Two new linear trinuclear complexes, [Co(NiL¹)₂(SCN)₂] (1) and [Co(NiL²)₂(H₂O)₂](ClO₄)₂?·?2C₂H₅OH (2), have been prepared by using Co(ClO₄)₂?·?6H₂O and two macrocyclic complex ligands NiL¹ and NiL². L¹ and L² are the doubly deprotonated forms of dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]tetraazabicyclo[12.4.0^15,16]13,18-dicarboxylate and dimethyl 5,6,7,8,15,16-hexahydro-15-methyl-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate, respectively. X-ray single crystal analyses reveal the coordination geometries around Ni(II) in both 1 and 2 are identical and slightly distorted square planar with N₄ donors; all Ni–N bonds in the two complexes are very short. The Co(II) ions are at the centers of the trinuclear complexes and have distorted octahedral coordination geometries of O₄N₂ donors in 1 and an O₆ in 2. π?···?π interactions involving aromatic and non-aromatic π-systems join the trinuclear entities to form 2-D layers in the crystals of 1 and 2.     

Syntheses, crystal structures and properties of two 1-D cadmium(II) coordination polymers based on 1,1′-(1,3-propanediyl)bis-1H-benzimidazole

The combination of framework-builders 1,1′-(1,3-propanediyl)bis-1H-benzimidazole (pbbm), Cd(II) ion and framework-regulator ClO₄⁻ or SO₄²⁻ provides two new coordination polymers [Cd(pbbm)₂(ClO₄)₂]_n(1) and {[Cd(pbbm)SO₄(H₂O)₂]·CH₃OH}_n(2). Both of them display 1-D chain framework, but their detailed structures are clearly different from each other. 1 displays a 1-D ribbon of rings framework, 2 features an interesting infinite 1-D looped chain structure composed of two kinds of rings, the smaller 8-membered ring and the larger 20-membered ring. The antimicrobial activities of the two polymers were tested by the agar diffusion method and the results indicated that they exhibited antimicrobial activities against bacterial strands. The measurement of the non-isothermal kinetics of the thermal decomposition of 2 reveals that there are at least three steps that occur in its decomposition process.     

Efficient photocatalytic degradation of methyl violet with two metall–organic frameworks

Two metal–organic frameworks, [Co₂(L)(H₂O)₂(4,4′-bipy)]·3CH₃CN (1) and [Mn₂(L)(1,10-phen)(H₂O)]·H₂O (2) (H₄L = 5-[bis(4-carboxybenzyl)-amino]isophthalic acid; 4,4′-bipy = 4,4′-bipyridine, 1,10-phen = 1,10-phenanthroline), with two different N-donor ligands have been synthesized. The structures of both MOFs were determined using single-crystal X-ray diffraction technique. MOF 1 shows 3D uncommon (4,6,6)-c net with (4.5³.6²)₂(5⁷.6⁶.8²)(4².5⁴.6⁶.7².8) topology while in the case of 2, only L^4? ligands link Mn(II) ions into a 2D layer structure with chelating 1,10-phen ligand. The results demonstrate that variation in the N-donor ligands plays a pivotal role in deciding the framework of the two MOFs. Both MOFs have been exploited as photocatalyst materials for the degradation of MV. The photocatalysis results indicate that the two MOFs are stable and are prospective candidates for degradation of methyl violet under UV light irradiation. Additionally, 2 displayed superior photocatalytic activity in comparison to 1. The probable photocatalytic activity mechanism for both 1 and 2 against MV has been proposed using density of states (DOS) calculations.     

A new oxamato-bridged heterotrinuclear NiIICuIINiII complex: synthesis,structure and properties

A new oxamato-bridged Ni^IICu^IINi^II species, [Ni(iprtacn)]₂[Cu(pba)(H₂O)_0.5](BPh₄)₂ (1), (iprtacn?=?1,4,7-triisopropyl-1,4,7-triazacyclononane; pba?=?1,3-propylenebis(oxamato)) has been synthesized and structurally as well as magnetically characterized. Complex 1 has a discrete trinuclear Ni^IICu^IINi^II structure: Two nickel(II) ions are bridged by [Cu(pba)]^2? with the macrocyclic ligand iprtacn a terminal ligand of nickel(II). Fitting the magnetic data of 1 led to g _Cu?=?2.16, g _Ni?=?2.18, J?=??112.5?cm^?1, D?=?±7.78?cm^?1. The irregular spin state structure and interaction of complex 1with DNA are described here.     

AN ALKOXO-BRIDGED BINUCLEAR MANGANESE COMPLEX BIS(μ-PROPIONATO-O: O′)-BIS(μ-3-SALICYLIDENE-AMINO-PROPANOLATO-O″,O‴,N:O″) BISMANGANESE(III)

Abstract

The alkoxo-bridged binuclear complex of Mn^III, [Mn₂(salpa)₂(C₂H₅—COO)₂] (H₂salpa = 3-salicylidene-amino-1-propanol), has been prepared and its crystal structure has been determined by X-ray diffraction. The structure of the title complex consists of discrete binuclear manganese units in which the Mn^III atoms are bridged by two alkoxo ligands via oxygen atoms and supported by two carboxylato bridging ligands in the syn - syn fashion. The complex lies about a crystallographic inversion center. Each Mn^III atom is located in an elongated octahedral environment with one imino N, one phenolic O and two alkoxo O atoms coordinated in the equatorial plane and two O atoms from carboxylato groups at the apical positions. The remarkably longer coordination bond distances in the axial direction are attributed to Jahn-Teller distortion at the d ⁴ manganese center. The distance between the manganese atoms is 2.8662(9) Å. The asymmetrical and symmetric stretching vibrations for carboxylato groups found at 1550 and 1440 cm^?1, respectively, with a separation of less than 200 cm^?1 confirmed the bidentate mode of the carboxylato groups.     

Two complexes based on 1H-1,2,3-triazole-4,5-dicarboxylic acid: hydrothermal synthesis,crystal structures and spectral properties

[Zn₃(tda)₂(bipy)₂(H₂O)_2?·?4H₂O] _n (1) and [Co₂(Htda)₂(H₂O)₆·5H₂O] (2) have been synthesized and characterized structurally by X-ray diffraction, where H₃tda?=?1H-1,2,3-triazole-4, 5-dicarboxylic acid and 2,2′-bipy?=?2,2′-bipyridine. Their solid-state structures have been characterized by elemental analysis and IR spectroscopy. The molecular unit of 1 consists of two crystallographically unique Zn(II) ions assuming different coordination geometries, the tda^3? exhibits a hexadentate binding mode chelating three Zn(II) ions; neighboring Zn–Zn distances through tda^3? bridges are 5.910(6), 5.888(5), and 6.279(3)?Å, respectively. In 2, two neighboring Co(II) ions are bridged by two Htda^2? ligands, forming a binuclear structure, with Co–Co distance of 4.091?Å and is further linked to generate a 3-D structure via hydrogen bonds. Fluorescent of 1 was investigated.     

Synthesis,crystal structures,and fluorescence properties of transition metal complexes derived from an unsymmetrical N-heterocyclic ligand

Four transition metal complexes, [Mn(Hbimtz)₂(H₂O)₂(NCS)₂] (1), [Co(Hbimtz)₂(H₂O)₂(NCS)₂] (2), [Pb(Hbimtz)Br₂] _n (3), and {[Ag₂(Hbimtz)₃]SO₄?·?4H₂O} _n (4) (Hbimtz?=?1-[(1H-benzimidazol-2-yl)-methyl]-1,2,3,4-tetrazole), were synthesized and characterized by single-crystal X-ray diffraction. The Mn(II) of 1 and Co(II) of 2 are six-coordinate with two nitrogen atoms from Hbimtz, two nitrogen atoms from thiocyanate and two water molecules. The geometry of Pb(II) in 3 is a distorted octahedron with two nitrogen atoms of two Hbimtz's and four Br^? ions, including the weak bond between the Pb1 and N6 of Hbimtz. Complex 3 is assembled into a 1-D [PbBr₂] _n inorganic chain by μ ₂-Br^? and into a 2-D layer by weak interactions. The Ag(II) of 4 has two geometries, linear and tetrahedral. Hbimtz bridges the two kinds of Ag(II) into a 1-D helical chain. Fluorescence of 3 and 4 were also investigated.     

Synthesis and structure of amide oxygen-bridged polymeric and monomeric copper(II) complexes with aroylhydrazones

The synthesis and structure of two Cu(II) complexes, {[Cu₂(L¹)₂]?·?DMF} _n (1) and [CuL²(phen)] (2), are described. The dinegative hydrazones are obtained by deprotonation of both phenolic and amide moieties of N′-(5-bromo-2-hydroxybenzylidene)-3,5-dimethoxybenzohydrazide (H₂L¹) and N′-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide (H₂L²). In each complex the planar ligand binds the metal ion via phenolate-O, imine-N, and amide-O. Complex 1 is a polymer in which phenoxo-bridged binuclear Cu(II) units are further joined by equatorial–apical amide-O bridges. The Cu···Cu separations are 3.0306 and 3.8217?Å for the phenolate-O bridged pair and the amide-O bridged pair, respectively. Complex 2 is a monomer where chelating phen displays axial–equatorial bonding, with square-pyramidal Cu(II).     

Mercury(II) cyanide complexes with alkyldiamines: solid-state/solution NMR,computational, and antimicrobial studies

Mercury cyanide complexes of alkyldiamines (1–6), [Hg(L)(CN)₂] (where L?=?en (1,2-diaminoethane), pn (1,3-diaminopropane), N-Me-en, N, N′-Me₂-en, N, N′-Et₂-en, and N, N′-ipr₂-en), have been synthesized and characterized by elemental analysis, IR, ¹³C, and ¹⁵N solution NMR in DMSO-d₆, as well as ¹³C, ¹⁵N, and ¹⁹⁹Hg solid-state NMR spectroscopy. Complexes 1 and 2 have been studied computationally, built and optimized by GAUSSIAN03 using DFT at B3LYP level with LanL2DZ basis set. Binding modes of en and bn (where bn?=?1,4-diaminobutane) toward Hg(CN)₂ are completely different. Complexes with en and pn show chelating binding to Hg(II), while bn behaves as a bridging ligand to form a polymeric structure, [Hg(CN)₂-bn]_∞ [B.A. Al-Maythalony, M. Fettouhi, M.I.M. Wazeer, A.A. Isab. Inorg. Chem. Commun., 12, 540 (2009).]. The solution ¹³C NMR of the complexes demonstrates a slight shift of the ?C≡N (0.9 to 2?ppm) and ?C–NH₂ (0.25 to 6?ppm) carbon resonances, while the other resonances are relatively unaffected. ¹⁵N labeling studies have shown involvement of alkyldiamine ligands in coordination to the metal. The principal components of the ¹³C, ¹⁵N, and ¹⁹⁹Hg shielding tensors have been determined from solid-state NMR data. Antimicrobial activity studies show that the complexes exhibit higher antibacterial activities toward various microorganisms than Hg(CN)₂.     

Cadmium(II) complexes with phosphine tellurides: synthesis and multinuclear (31P, 125Te,and 113Cd) NMR characterization in solution

New cadmium(II) complexes with phosphine telluride ligands of the type CdX₂(R₃PTe)_n [X?=?ClO₄^?, n?=?4: R?=?n-Bu (1), Me₂?N (2), C₅H₁₀?N (3), C₄H₈?N (4) or OC₄H₈?N (5); X?=?Cl^–, n?=?2: R?=?n-Bu (6), Me₂?N (7), C₅H₁₀?N (8), C₄H₈?N (9) or OC₄H₈?N (10)] have been synthesized and characterized by elemental analyses, IR and multinuclear (³¹P, ¹²⁵Te, and ¹¹³Cd) NMR spectroscopy. In particular, the solution structures of these complexes were confirmed by ¹¹³Cd NMR at low temperature, which displays a quintuplet for each of the perchlorate complexes and a triplet for each of the chloride complexes due to coupling with four and two equivalent phosphorus atoms, respectively, indicating a four-coordinate tetrahedral geometry for the metal center. These multiplet features were further accompanied by one bond Te–Cd couplings, clearly showing that the ligand is coordinated to the metal through tellurium. The results are discussed and compared with those obtained for closely related phosphine chalcogenide analogs.     

Six lanthanide(III) coordination polymers with 3,5-bis(4′-carboxy-phenyl)-1,2,4-triazole: syntheses,structures, and photoluminescence

Six 3-D lanthanide(III)-metal-organic frameworks (MOFs) through multidentate 3,5-bis(4′-carboxy-phenyl)-1,2,4-triazole (H₂BCPT); acetic acid (HOAc); and corresponding trivalent rare earth chloride, {[Ln(BCPT)(OAc)(H₂O)]·(H₂O)}_n (Ln = Nd³⁺ (1); Sm³⁺ (2), Gd³⁺ (3), Tb³⁺ (4), Ho³⁺ (5), Yb³⁺ (6)), have been synthesized. MOFs 1–6 were characterized via FT-IR spectroscopy, elemental analysis, X-ray single-crystal diffraction, thermal analysis, and fluorescence. MOFs 1–6 are isomorphous, which can be described as a 3-D construction containing a dinuclear cluster [Tb₂(CO₂)₂(O)₂]. The 3-D structure with (4,4) topologies have been extended through BCPT^2? using μ₄-kO;kO;kO;kO coordination modes. Solid-state luminescence of 1–4 and 6 shows the characteristic bands of Nd³⁺, Sm³⁺, Tb³⁺, and Yb³⁺ from visible to near-infrared spectral regions.     

Synthesis and spectral studies of some new dimeric [(μ-Cl)2M2(L)2 · xTHF] [M = Zn(II) and Hg(II)] complexes containing Schiff-base ligands

A series of binuclear Schiff-base complexes of zinc(II) and mercury(II) containing bidentate ligands (HL) [HL?=?salicylidene-2-methyl-1-aminobenzene (HL¹), salicylidene-2-aminopyridine (HL²), and salicylidene-3-nitro-1-aminobenzene (HL³)] with “N” and “O” donors have been synthesized by simple metathetic reactions of anhydrous metal chlorides with sodium salts of Schiff bases (in tetrahydrofuran (THF)/MeOH) in equimolar ratio to produce [(µ-Cl)₂M₂(L)₂?·?xTHF] [where M?=?Zn(II) and Hg(II); L?=?HL¹, HL², and HL³; x?=?0 for (1), (4), (6) and x?=?2 for (2), (3), (5)]. The main emphasis on the complexes [(µ-Cl)₂M₂(L)₂?·?2THF] (2), (3), and (5) is given due to their five-coordinate environment around metal ions. The complexes have been characterized by elemental analyses (M, Cl, C, H, N), melting point, and spectral (FT-IR, ¹H-NMR, and ¹³C-NMR) studies. The structural composition of the complexes has been determined by FAB-MS spectral studies. FAB-MS showed the isotopic molecular ion peak [M⁺] and fragments supporting the formulation. Powder X-ray diffraction study of 6 is also reported showing the crystallite size (404.5?Å) of the complex.