catena‐Poly[[silver(I)‐μ‐1,3‐bis(4‐pyridyl)propane] hemi(naphthalene‐1,5‐disulfonate) dihydrate]: a three‐dimensional metallo‐supramolecular sandwich lamellar network

The title compound, {[Ag(C₁₃H₁₄N₂)](C₁₀H₆O₆S₂)_0.5·2H₂O}_n, (I), features a three‐dimensional supramolecular sandwich architecture that consists of two‐dimensional cationic layers composed of polymeric chains of silver(I) ions and 1,3‐bis(4‐pyridyl)propane (bpp) ligands, linked by Ag...Ag and π–π interactions, alternating with anionic layers in which uncoordinated naphthalene‐1,5‐disulfonate (nds²⁻) anions and solvent water molecules form a hydrogen‐bonded network. The asymmetric unit consists of one Ag^I cation linearly coordinated by N atoms from two bpp ligands, one bpp ligand, one half of an nds²⁻ anion lying on a centre of inversion and two solvent water molecules. The two‐dimensional {[Ag(bpp)]⁺}_n cationic and {[(nds)·2H₂O]²⁻}_n anionic layers are assembled into a three‐dimensional supramolecular framework through long secondary coordination Ag...O interactions between the sulfonate O atoms and Ag^I centres and through nonclassical C—H...O hydrogen bonds.     

Studies on mono- and dinuclear bisoxime copper complexes with different coordination geometries

Two new mono- and dinuclear Cu(II) complexes, namely [CuL¹]·0.5H₂O (1) and [(Cu₂(L²)₂)(DMF)]·0.5DMF (2) (H₂L¹ = 1,2-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)]methylene-aminooxy}ethane; H₂L² = 1,3-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)] methyleneaminooxy}propane), have been synthesized and characterized by X-ray crystallography. The unit cell of complex 1 contains two crystallographically independent but chemically identical [CuL¹] molecules and one crystalline water molecule, showing a slightly distorted square-planar coordination geometry and forming a wave-like pattern running along the a-axis via hydrogen bonding and π···π stacking interactions. Complex 2 has a dinuclear structure, comprising two Cu(II) atoms, two completely deprotonated phenolate bisoxime (L²)²⁻ moieties (in the form of enol), and both coordinated and hemi-crystalline DMF molecules. Complex 2 has square-planar and square-pyramidal geometries around the two copper centers, whose basic coordination planes are almost perpendicular and form an infinite three-dimensional supramolecular network structure involving intermolecular C–H···N, C–H···O, and C–H···π(Ph) hydrogen bonding and π···π stacking interactions of neighboring pyrazole rings.     

Saccharified Uranyl Ions: Self-Assembly of UO22+ into Trinuclear Anionic Complexes by the Coordination of Glucosamine-Derived Schiff Bases

The reaction of UO₂(OAc)₂ ⋅ 2H₂O with the biologically inspired ligand 2-salicylidene glucosamine (H₂ L¹ ) results in the formation of the anionic trinuclear uranyl complex [(UO₂)₃(μ₃-O)( L¹ )₃]²⁻ ( 1 ²⁻), which was isolated in good yield as its Cs-salt, [Cs]₂ 1 . Recrystallization of [Cs]₂ 1 in the presence of 18-crown-6 led to formation of a neutral ion pair of type [M(18-crown-6)]₂ 1 , which was also obtained for the alkali metal ions Rb⁺ and K⁺ (M=Cs, Rb, K). The related ligand, 2-(2-hydroxy-1-naphthylidene) glucosamine (H₂ L² ) in a similar procedure with Cs⁺ gave the corresponding complex [Cs(18-crown-6)]₂[(UO₂)₃(μ₃-O)( L² )₃ ([Cs(18-crown-6)]₂ 2 ). From X-ray investigations, the [(UO₂)₃O( Lⁿ )₃]²⁻ anion (n=1, 2) in each complex is a discrete trinuclear uranyl species that coordinates to the alkali metal ion via three uranyl oxygen atoms. The coordination behavior of H₂ L¹ and H₂ L² towards UO₂²⁺ was investigated by NMR, UV/Vis spectroscopy and mass spectrometry, revealing the in situ formation of the 1 ²⁻ and 2 ²⁻dianions in solution.     

A novel two‐dimensional cobalt(II) complex composed of one‐dimensional twisted pair‐like chains: poly[[tetraaquabis(μ3‐pyridine‐2,5‐dicarboxylato‐κ4N,O2:O5:O5′)dicobalt(II)] dihydrate]

A novel neutral polymer, {[Co₂(C₇H₃NO₄)₂(H₂O)₄]·2H₂O}_n, was hydrothermally synthesized using pyridine‐2,5‐dicarboxylate (2,5‐PDC²⁻) as the organic linker. It features a two‐dimensional layer structure constructed from one‐dimensional {[Co(2,5‐PDC)₂]²⁻}_n chains interlinked by [Co(H₂O)₄]⁺ units. The two Co^II cations occupy special positions, sitting on inversion centres. Each 2,5‐PDC²⁻ anion chelates to one Co^II cation via the pyridine N atom and an O atom of the adjacent carboxylate group, and links to two other Co^II cations in a bridging mode via the O atoms of the other carboxylate group. In this way, the 2,5‐PDC²⁻ ligand connects three neighbouring Co^II centres to form a two‐dimensional network. The two‐dimensional undulating layers are linked by extensive hydrogen bonds to form a three‐dimensional supramolecular structure, with the uncoordinated solvent molecules occupying the interlamellar region.     

The three‐dimensional coordination polymer poly[[aqua[μ4‐2,2′‐(diazene‐1,2‐diyl)dibenzoato]lead(II)] 1,2‐bis(pyridin‐4‐yl)ethylene hemisolvate]

A novel three‐dimensional coordination polymer, {[Pb(C₁₄H₈N₂O₄)(H₂O)]·0.5C₁₂H₁₀N₂}_n, has been synthesized by hydrothermal reaction of Pb(OAc)₂·3H₂O (OAc is acetate), 2,2′‐(diazene‐1,2‐diyl)dibenzoic acid (H₂L) and 1,2‐bis(pyridin‐4‐yl)ethylene (bpe). The asymmetric unit contains a crystallographically independent Pb^II cation, one L²⁻ ligand, an aqua ligand and half a bpe molecule. Each Pb^II centre is seven‐coordinated by six O atoms of bridging–chelating carboxylate groups from L²⁻ ligands and by one O atom from a coordinated water molecule. The Pb^II cations are bridged by L²⁻ ligands, forming [PbO₂]_n chains along the a axis. These chains are further connected by L²⁻ ligands along the b and c axes to give a three‐dimensional framework with a 4¹²6³ topology. The channel voids are occupied by bpe molecules.     

Electrochemical Synthesis and Characterization of Tin(IV) Complexes of Dianionic Terdentate Schiff Base Ligands

Tin(IV) complexes of the series of dianionic terdentate Schiff bases N‐[(2‐pyrroyl)methylidene]‐N′‐tosylbenzene‐1,2‐diamine, (H₂L¹), N‐[(2‐hydroxyphenyl)methylidene]‐N′‐tosylbenzene‐1,2‐diamine (H₂L²) and some R substituted 2‐{[(2‐hydroxyphenyl)imino]methyl}phenols [R = H (H₂L³), 4,6‐(OCH₃)₂ (H₂L⁴), 3‐(OC₂H₅) (H₂L⁵) and 3,5‐Br₂ (H₂L⁶)] have been synthesized. The compounds were obtained by the electrochemical oxidation of a tin anode in a cell containing an acetonitrile solution of the corresponding ligand. The complex [SnL¹₂] was also obtained by reaction of SnCl₂·2H₂O and H₂L¹ in methanol in the presence of triethylamine. The crystal structure of the ligand [H₂L⁶] and the complexes [SnL¹₂] (1) , [SnL²₂] (2) , [SnL³₂] (3) and [SnL⁶₂] (6) were determined by X‐ray diffraction. In the complexes, the tin atom is in an octahedral environment coordinated by two dianionic terdentate ligands. Spectroscopic data for the complexes (IR, ¹H and ¹¹⁹Sn NMR and mass spectra) are discussed and related to structural information.     

Eight salt forms of sulfadiazine

Proton transfer to the sulfa drug sulfadiazine [systematic name: 4‐amino‐N‐(pyrimidin‐2‐yl)benzenesulfonamide] gave eight salt forms. These are the monohydrate and methanol hemisolvate forms of the chloride (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride monohydrate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·H₂O, (I), and 2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium chloride methanol hemisolvate, C₁₀H₁₁N₄O₂S⁺·Cl⁻·0.5CH₃OH, (II)); a bromide monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium bromide monohydrate, C₁₀H₁₁N₄O₂S⁺·Br⁻·H₂O, (III)), which has a disordered water channel; a species containing the unusual tetraiodide dianion [bis(2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium) tetraiodide, 2C₁₀H₁₁N₄O₂S⁺·I₄²⁻, (IV)], where the [I₄]²⁻ ion is located at a crystallographic inversion centre; a tetrafluoroborate monohydrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium tetrafluoroborate monohydrate, C₁₀H₁₁N₄O₂S⁺·BF₄⁻·H₂O, (V)); a nitrate (2‐{[(4‐azaniumylphenyl)sulfonyl]azanidyl}pyrimidin‐1‐ium nitrate, C₁₀H₁₁N₄O₂S⁺·NO₃⁻, (VI)); an ethanesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium ethanesulfonate, C₁₀H₁₁N₄O₂S⁺·C₂H₅SO₃⁻, (VII)}; and a dihydrate of the 4‐hydroxybenzenesulfonate {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium 4‐hydroxybenzenesulfonate dihydrate, C₁₀H₁₁N₄O₂S⁺·HOC₆H₄SO₃⁻·2H₂O, (VIII)}. All these structures feature alternate layers of cations and of anions where any solvent is associated with the anion layers. The two sulfonate salts are protonated at the aniline N atom and the amide N atom of sulfadiazine, a tautomeric form of the sulfadiazine cation that has not been crystallographically described before. All the other salt forms are instead protonated at the aniline group and on one N atom of the pyrimidine ring. Whilst all eight species are based upon hydrogen‐bonded centrosymetric dimers with graph set R₂²(8), the two sulfonate structures also differ in that these dimers do not link into one‐dimensional chains of cations through NH₃‐to‐SO₂ hydrogen‐bonding interactions, whilst the other six species do. The chloride methanol hemisolvate and the tetraiodide are isostructural and a packing analysis of the cation positions shows that the chloride monohydrate structure is also closely related to these.     

Linking Chiral Clusters with Molybdate Building Blocks: From Homochiral Helical Supramolecular Arrays to Coordination Helices

The synthesis of four new oxo‐centered Fe clusters ( 1 a – c , 2 ) of the form [Fe^III₃(μ₃‐O)(CH₂=CHCOO)₆] with acrylate as the bridging ligand gives rise to potentially intrinsically chiral oxo‐centered {M₃} trimers that show a tendency to spontaneously resolve upon crystallization. For instance, 1 a , [Fe^III₃(μ₃‐O)(CH₂=CHCOO)₆‐(H₂O)₃]⁺, crystallizes in the chiral space group P3₁ as a chloride salt. Crystallization of 1 b , [Fe₃(μ₃‐O)(C₂H₃CO₂)₆(H₂O)₃]NO₃?4.5H₂O, from aqueous solution followed by recrystallization from acetonitrile also gives rise to spontaneous resolution to yield the homochiral salt [Fe₃(μ₃‐O)(C₂H₃CO₂)₆‐(H₂O)₃]NO₃?CH₃CN of 1 c (space group P2₁2₁2₁). Furthermore, the reaction of 1 a with hexamolybdate in acetonitrile gives the helical coordination polymer {[(Fe₃(μ₃‐O)L₆(H₂O))(MoO₄)‐(Fe₃(μ₃‐O)L₆(H₂O)₂)]?2CH₃CN?H₂O}_∞ 2 (L: H₂C?CHCOO), which crystallizes in the space group P2₁. The nature of the ligand geometry allows the formation of atropisomers in both the discrete ( 1 a – c ) and linked {Fe₃} clusters ( 2 ), which is described along with a magnetic analysis of 1 a and 2 .     

Versatile 2,5‐Pyridinedicarboxylate in Linking Transition‐Metal Atoms into 1D and 2D Coordination Polymers and Concomitant Polymorphs

By employing one bridging ligand, 2,5‐pyridinedicarboxylate (2,5‐pda^2?), in the presence or absence of another bridging ligand, 4,4′‐bipyridine (4,4′‐bpy), one one‐dimensional (1D) {[Co₂(2,5‐pda)(2,5‐Hpda)₂(4,4′‐bpy)(H₂O)₃]·6H₂O}_∞ ( 1 ) and two two‐dimensional (2D) coordination polymers, {[Cu₃(2,5‐pda)₃(H₂O)₃]·6H₂O}_∞ ( 2 ) and {[Co(2,5‐pda)(H₂O)]·2H₂O}_∞ ( 3 ) were synthesized. Complexes 2 and 3 are characterized as concomitant polymorphs from a one‐pot reaction at ambient temperature. A comparison of the coordination geometries of all neutral and anionic coordination polymers containing {M_x(2,5‐pda)_y(H₂O)_z}_∞ available to date is presented.     

A two‐dimensional cadmium(II) coordination polymer based on 5‐(pyridin‐4‐yl)isophthalic acid: poly[[tetraaquabis[μ3‐5‐(pyridin‐4‐yl)isophthalato]dicadmium(II)] pentahydrate]

The title Cd^II compound, {[Cd₂(C₁₃H₇NO₄)₂(H₂O)₄]·5H₂O}_n, was synthesized by the hydrothermal reaction of Cd(NO₃)₂·4H₂O and 5‐(pyridin‐4‐yl)isophthalic acid (H₂L). The asymmetric unit contains two crystallographically independent Cd^II cations, two deprotonated L²⁻ ligands, four coordinated water molecules and five isolated water molecules. One of the Cd^II cations adopts a six‐coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. The second Cd^II cation adopts a seven‐coordinate pentagonal–bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L²⁻ ligands, one N atom of another L²⁻ ligand and two coordinated water molecules. Each L²⁻ ligand bridges three Cd^II cations and, likewise, each Cd^II cation connects to three L²⁻ ligands, giving rise to a two‐dimensional graphite‐like 6³ layer structure. These two‐dimensional layers are further linked by O—H...O hydrogen‐bonding interactions to form a three‐dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.     

Preparation and Characterization of Dinuclear Chromium(III) Complexes of a Hexadentate Tetraaza‐Dithiophenolate Ligand

The ability of the tetraaza‐dithiophenolate ligand H₂L² (H₂L² = N,N′‐Bis‐[2‐thio‐3‐aminomethyl‐5‐tert‐butyl‐benzyl]propane‐1,3‐diamine) to form dinuclear chromium(III) complexes has been examined. Reaction of Cr^IICl₂ with H₂L² in methanol in the presence of base followed by air‐oxidation afforded cis,cis‐[(L²)Cr^III₂(μ‐OH)(Cl)₂]⁺ ( 1a ) and trans,trans‐[(L²)Cr^III₂(μ‐OH)(Cl)₂]⁺ ( 1b ). Both compounds contain a confacial bioctahedral N₂ClCr^III(μ‐SR)₂(μ‐OH)Cr^IIIClN₂ core. The isomers differ in the mutual orientation of the coligands and the conformation of the supporting ligand. In 1a both Cl^? ligands are cis to the bridging OH function. In 1b they are in trans‐positions. Reaction of the hydroxo‐bridged complexes with HCl yielded the chloro‐bridged cations cis,cis‐[(L²)Cr^III₂(μ‐Cl)(Cl)₂]⁺ ( 2a ) and trans,trans‐[(L²)Cr^III₂(μ‐Cl)(Cl)₂]Cl ( 2b ), respectively. These bridge substitutions proceed with retention of the structures of the parent complexes 1a and 1b .     

Gallium “Shears” for C=N and C=O Bonds of Isocyanates

Digallane [L¹Ga−GaL¹] ( 1 , L¹=dpp-bian=1,2-[(2,6-iPr₂C₆H₃)NC]₂C₁₂H₆) reacts with RN=C=O (R=Ph or Tos) by [2+4] cycloaddition of the isocyanate C=N bonds across both of its C=C−N−Ga fragments to afford [L¹(O=C−NR)Ga−Ga(RN−C=O)L¹] (R=Ph, 3 ; R=Tos, 4 ). The reactions with both isocyanates result in new C−C and N−Ga single bonds. In the case of allyl isocyanate, the [2+4] cycloaddition across one C=C−N−Ga fragment of 1 is accompanied by insertion of a second allyl isocyanate molecule into the Ga−N bond of the same fragment to afford compound [L¹Ga−Ga(AllN− C=O)₂L¹] ( 5 ) (All=allyl). In the presence of Na metal, the related digallane [L²Ga−GaL²] ( 2 ; L²=dpp-dad=[(2,6-iPr₂C₆H₃)NC(CH₃)]₂) is converted into the gallium(I) carbene analogue [L²Ga:]⁻ ( 2 A ), which undergoes a variety of reactions with isocyanate substrates. These include the cycloaddition of ethyl isocyanate to 2 A affording [Na₂(THF)₅]{L²Ga[EtN−C(O)]₂GaL²} ( 6 ), cleavage of the N=C bond with release of 1 equiv. of CO to give [Na(THF)₂]₂[L²Ga(p-MeC₆H₄)(N−C(O))₂−N(p-MeC₆H₄)]₂ ( 7 ), cleavage of the C=O bond to yield the di-O-bridged digallium compound [Na(THF)₃]₂[L²Ga-(μ-O)₂-GaL²] ( 8 ), and generation of the further addition product [Na₂(THF)₅][L²Ga(CyNCO₂)]₂ ( 9 ). Complexes 3 – 9 have been characterized by NMR (¹H, ¹³C), IR spectroscopy, elemental analysis, and X-ray diffraction analysis. Their electronic structures have been examined by DFT calculations.     

Salt forms of the pharmaceutical amide dihydrocarbamazepine

Carbamazepine (CBZ) is well known as a model active pharmaceutical ingredient used in the study of polymorphism and the generation and comparison of cocrystal forms. The pharmaceutical amide dihydrocarbamazepine (DCBZ) is a less well known material and is largely of interest here as a structural congener of CBZ. Reaction of DCBZ with strong acids results in protonation of the amide functionality at the O atom and gives the salt forms dihydrocarbamazepine hydrochloride {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium chloride, C₁₅H₁₅N₂O⁺·Cl⁻}, dihydrocarbamazepine hydrochloride monohydrate {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium chloride monohydrate, C₁₅H₁₅N₂O⁺·Cl⁻·H₂O} and dihydrocarbamazepine hydrobromide monohydrate {systematic name: [(10,11‐dihydro‐5H‐dibenzo[b,f]azepin‐5‐yl)(hydroxy)methylidene]azanium bromide monohydrate, C₁₅H₁₅N₂O⁺·Br⁻·H₂O}. The anhydrous hydrochloride has a structure with two crystallographically independent ion pairs (Z′ = 2), wherein both cations adopt syn conformations, whilst the two hydrated species are mutually isostructural and have cations with anti conformations. Compared to neutral dihydrocarbamazepine structures, protonation of the amide group is shown to cause changes to both the molecular (C=O bond lengthening and C—N bond shortening) and the supramolecular structures. The amide‐to‐amide and dimeric hydrogen‐bonding motifs seen for neutral polymorphs and cocrystalline species are replaced here by one‐dimensional polymeric constructs with no direct amide‐to‐amide bonds. The structures are also compared with, and shown to be closely related to, those of the salt forms of the structurally similar pharmaceutical carbamazepine.     

Different Complexation Behavior of P‐Functionalized Ferrocene Derivatives Towards SnCl2, SnCl4 and SnPh2Cl2: Auto‐ionization and Redox‐Type Reactions

The novel phosphonyl‐substituted ferrocene derivatives [Fe(η⁵‐Cp)(η⁵‐C₅H₃{P(O)(O‐iPr)₂}₂‐1,2)] ( Fc^1,2 ) and [Fe{η⁵‐C₅H₄P(O)(O‐iPr)₂}₂] ( Fc^1,1′ ) react with SnCl₂, SnCl₄, and SnPh₂Cl₂, giving the corresponding complexes [(Fc^1,2)₂SnCl][SnCl₃] ( 1 ), [{(Fc^1,1′)SnCl₂}_n] ( 2 ), [(Fc^1,1′)SnCl₄] ( 3 ), [{(Fc^1,1′)SnPh₂Cl₂}_n] ( 4 ), and [(Fc^1,2)SnCl₄] ( 5 ), respectively. The compounds are characterized by elemental analyses, ¹H, ¹³C, ³¹P, ¹¹⁹Sn NMR and IR spectroscopy, ³¹P and ¹¹⁹Sn CP‐MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single‐crystal as well as powder X‐ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc^1,1′ and Fc^1,2 towards tin(II) chloride.     

Tetrakis­(diethyl­amino)­phospho­nium bromide hemihydrate

The structure of the title compound, C₁₆H₄₀N₄P⁺·Br^?·0.5H₂O or [P{N(C₂H₅)₂}₄]Br·0.5H₂O, at 130 K has Z′ = 4 and is ionic, with Br not bonded to P. The P atoms are tetrahedral, with P—N distances in the range 1.628 (2)–1.6400 (19) Å. The N atoms are approximately planar. The water mol­ecules form cyclic hydrogen‐bonded [(H₂O)₂Br₂]^2? units about inversion centers, with O?Br distances in the range 3.425 (2)–3.611 (3) Å.     

Two different one‐dimensional structural motifs in [catena‐{Cu(tacn)}2Pd(CN)4]Br2·[catena‐Cu(tacn)Pd(CN)4]2·H2O (tacn is 1,4,7‐triazacyclononane)

The title compound, catena‐poly[[bis[(triazacyclononane‐κ³N,N′,N′′)copper(II)]‐di‐μ‐cyanido‐κ⁴N:C‐palladate(II)‐di‐μ‐cyanido‐κ⁴C:N] dibromide bis[[(triazacyclononane‐κ³N,N′,N′′)copper(II)]‐μ‐cyanido‐κ²N:C‐[dicyanidopalladate(II)]‐μ‐cyanido‐κ²C:N] monohydrate], {[Cu₂Pd(CN)₄(C₆H₁₅N₃)₂]Br₂·[Cu₂Pd₂(CN)₈(C₆H₁₅N₃)₂]·H₂O}_n, (I), was isolated from an aqueous solution containing tacn·3HBr (tacn is 1,4,7‐triazacyclononane), Cu²⁺ and tetracyanidopalladate(2−) anions. The crystal structure of (I) is essentially ionic and built up of 2,2‐electroneutral chains, viz. [Cu(tacn)(NC)–Pd(CN)₂–(CN)–], positively charged 2,4‐ribbons exhibiting the composition {[Cu(tacn)(NC)₂–Pd(CN)₂–Cu(tacn)]²ⁿ⁺}_n, bromide anions and one disordered water molecule of crystallization. The O atom of the water molecule occupies two unique crystallographic positions, one on a centre of symmetry, which is half occupied, and the other in a general position with one‐quarter occupancy. One of the tacn ligands also exhibits disorder. The formation of two different types of one‐dimensional structural motif within the same structure is a unique feature of this compound.     

Trapping Dimethyltin Cations by Bipyridine‐N,N′‐Dioxide Ligands

N,N′‐dioxide ligands such as 2, 2′‐bipyridine‐N,N‐dioxide (BPDO‐I) and 4, 4′‐bipyridine‐N,N‐dioxide (BPDO‐II) were used to trap the hydrated dimethyltin cations under controlled hydrolysis. The use of the chelating ligand BPDO‐I leads to the isolation of the discrete monocation [Me₂Sn(BPDO‐I)(OH₂)(NO₃)]⁺[NO₃]^– ( 2 ), whereas the linear ligand BPDO‐II directs the construction of cationic polymers, [{Me₂Sn(OH₂)₂(μ‐BPDO‐II)}²⁺{NO₃^–}₂ · 2H₂O]_n ( 3· 2H₂O) and [{Me₂Sn(μ‐OH)(BPDO‐II)}₂²⁺{NO₃^–}₂ · H₂O]_n ( 4· H₂O) under different reaction conditions.     

Novel platinum(II) and (IV) complexes of naphthaldimine schiff bases

Naphthaldimines containing N₂O₂ donor centers react with platinum(II) and (IV) chlorides to give two types of complexes depending on the valence of the platinum ion. For [Pt(II)], the ligand is neutral, [(H₂L¹)PtCl₂]·3H₂O (1) and [(H₂L³)₂Pt₂Cl₄]·5H₂O (3), or monobasic [(HL²)₂Pt₂Cl₂]·2H₂O (2) and [(HL⁴)₂Pt]·2H₂O (4). These complexes are all diamagnetic having square-planar geometry. For [Pt(IV)], the ligand is dibasic, [(L¹)Pt₂Cl₄(OH)₂]·2H₂O (5), [(L²)Pt₃Cl₁₀]·3H₂O (6), [(L³)Pt₂Cl₄(OH)₂]·C₂H₅OH (7) and [(L⁴)Pt₂Cl₆]·H₂O (8). The Pt(IV) complexes are diamagnetic and exhibit octahedral configuration around the platinum ion. The complexes were characterized by elemental analysis, UV-Vis and IR spectra, electrical conductivity and thermal analyses (DTA and TGA). The molar conductances in DMF solutions indicate that the complexes are non-ionic. The complexes were tested for their catalytic activities towards cathodic reduction of oxygen.     

Bis(methyltri‐o‐tolylphosphonium) octaiodide

In the crystal structure of the title compound, 2C₂₂H₂₄P⁺·I₈²⁻, the I₈²⁻ anion is located on a crystallographic inversion centre and consists of two tri‐iodide anions linked by di‐iodine at angles of 89.92 (4)° to form a planar `Z'‐shaped dianion. The octaiodides are linked via long‐range interactions [3.877 (11) Å] into infinite polyiodide ribbons. This is the first example of a structure containing an [(o‐tolyl)₃PMe]⁺ cation, and the C_Me—P—C—C_Me torsion angles of −54.0 (11), −51.3 (11) and −48.2 (11)° indicate that the configuration is exo₃.