Four (2,2′‐bipyridyl)(ferrocenyl)boronium derivatives

Crystal structures are reported for four (2,2′‐bipyridyl)(ferrocenyl)boronium derivatives, namely (2,2′‐bipyridyl)(ethenyl)(ferrocenyl)boronium hexafluoridophosphate, [Fe(C₅H₅)(C₁₇H₁₅BN₂)]PF₆, (Ib), (2,2′‐bipyridyl)(tert‐butylamino)(ferrocenyl)boronium bromide, [Fe(C₅H₅)(C₁₉H₂₂BN₃)]Br, (IIa), (2,2′‐bipyridyl)(ferrocenyl)(4‐methoxyphenylamino)boronium hexafluoridophosphate acetonitrile hemisolvate, [Fe(C₅H₅)(C₂₂H₂₀BN₃O)]PF₆·0.5CH₃CN, (IIIb), and 1,1′‐bis[(2,2′‐bipyridyl)(cyanomethyl)boronium]ferrocene bis(hexafluoridophosphate), [Fe(C₁₇H₁₄BN₃)₂](PF₆)₂, (IVb). The asymmetric unit of (IIIb) contains two independent cations with very similar conformations. The B atom has a distorted tetrahedral coordination in all four structures. The cyclopentadienyl rings of (Ib), (IIa) and (IIIb) are approximately eclipsed, while a bisecting conformation is found for (IVb). The N—H groups of (IIa) and (IIIb) are shielded by the ferrocenyl and tert‐butyl or phenyl groups and are therefore not involved in hydrogen bonding. The B—N(amine) bond lengths are shortened by delocalization of π‐electrons. In the cations with an amine substituent at boron, the B—N(bipyridyl) bonds are 0.035 (3) Å longer than in the cations with a methylene C atom bonded to boron. A similar lengthening of the B—N(bipyridyl) bonds is found in a survey of related cations with an oxy group attached to the B atom.     

Redetermination of the crystal structure of boron subphthalocyanine chloride (Cl‐BsubPc) enabled by slow train sublimation

The crystal structure of boron subphthalocyanine chloride [systematic name: chlorido(subphthalocyaninato)boron], C₂₄H₁₂BClN₆, a material of widespread interest in organic electronic device applications, has been redetermined with a higher precision using large single crystals obtained via slow train sublimation. Details are given for the construction and operation of the train sublimation system, which has been designed to reproducibly yield single crystals suitable for diffraction experiments in a manner which approximates the vacuum deposition conditions commonly used to fabricate organic electronic devices. Diffraction experiments were conducted using two crystal samples and four temperatures (90, 123, 147 and 295 K), enabling a discussion of changes in the unit cell and intermolecular interactions with respect to temperature and in comparison to two previously published structures of Cl‐BsubPc. The redetermined structure confirms the original structure published 41 years ago [Meller & Ossko (1972). Monatsh. Chem. 103 , 150–155], with significantly improved precision for the geometric parameters. Analysis of the crystal structure revealed three intersecting ribbon motifs formed through a combination of π–π and halogen–π (specifically B—Cl…π) interactions. H atoms were refined independently in order to facilitate a thorough discussion of these intermolecular interactions using Hirshfeld surface analysis.     

Pyrene‐Bridged Boron Subphthalocyanine Dimers: Combination of Planar and Bowl‐Shaped π‐Conjugated Systems for Creating Uniquely Curved π‐Conjugated Systems

Pyrene‐bridged boron subphthalocyanine dimers were synthesized from a mixed‐condensation reaction of 2,7‐di‐tert‐butyl‐4,5,9,10‐tetracyanopyrene and tetrafluorophthalonitrile, and their syn and anti isomers arising from the result of connecting two bowl‐shaped boron subphthalocyanine molecules were successfully separated. Expansion of the conjugated system of boron subphthalocyanine through a pyrene bridge caused a redshift of the Q band absorption relative to the parent pyrene‐fused monomer, whereas combining the curved π‐conjugation of boron subphthalocyanine with the planar π‐conjugation of pyrene enabled facile embracement of C₆₀ molecules, owing to the enhanced concave–convex π–π stacking interactions.     

Two closely related {4‐[(N‐substituted amino)(diethoxyphosphoryl)methyl]phenyl}boronic acids

Organic phosphonic acids and organic phosphonic acid esters have been of much interest due to their applications in the fields of medicine, agriculture and industrial chemistry. Boronic acids can act as synthetic intermediates and building blocks and are used in sensing, protein manipulation, therapeutics, biological labelling and separation. The additional introduction of an aminophosphonic acid group into a boronic acid may give new opportunities for application. To study the structure of such multifunctional compounds, we prepared two new derivatives which can be easily converted to the corresponding phosphonic acids. In the title compounds, {4‐[(butylamino)(diethoxyphosphoryl)methyl]phenyl}boronic acid monohydrate, C₁₅H₂₇BNO₅P·H₂O, (I), and {4‐[(diethoxyphosphoryl)(4‐nitroanilino)methyl]phenyl}boronic acid, C₁₇H₂₂BN₂O₇P, (II), three different substituents are attached to a central C—H group, namely 4‐boronophenyl, diethoxyphosphoryl and amine. Compound (I) crystallizes as a monohydrate and O_B—H…N hydrogen bonds link neighbouring molecules into chains along the [001] direction. The solvent water molecule connects two such chains running in opposite directions. Compound (II) crystallizes as an ansolvate and classical hydrogen bonds result in a layer structure in the (001) plane.     

Salt forms of sulfadiazine with alkali metal and organic cations

The structures of four salt forms of sulfadiazine (SDH) with alkali metal cations are presented. Three contain the deprotonated SD anion (C₁₀H₉N₄O₂S). These are the discrete complex diaqua{4‐[(pyrimidin‐2‐ylazanidyl‐κN¹)sulfonyl‐κO]aniline}lithium(I), [Li(SD)(H₂O)₂], (I), and the coordination polymers poly[{μ₃‐4‐[(pyrimidin‐2‐ylazanidyl)sulfonyl]aniline}sodium(I)], [Na(SD)]_n, (II), and poly[diaqua{μ₃‐4‐[(pyrimidin‐2‐ylazanidyl)sulfonyl]aniline}potassium(I)], [K(SD)(H₂O)₂]_n, (III). Na complex (II) is a three‐dimensional coordination polymer, whilst K complex (III) has two crystallographically independent [K(SD)(H₂O)₂] units per asymmetric unit (Z′ = 2) and gives a two‐dimensional coordination polymer whose layers propagate parallel to the crystallographic ab plane. The different bonding modes of the SD anion in these three complexes is discussed. Structure (IV) contains protonated SDH₂ cations {4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium, C₁₀H₁₁N₄O₂S} and the Orange G dianion [OG, 7‐oxo‐8‐(phenylhydrazinylidene)naphthalene‐1,3‐disulfonate, C₁₆H₁₀N₂O₇S₂], namely, 4‐[(pyrimidin‐2‐yl)sulfamoyl]anilinium tetraaqua[7‐oxo‐8‐(phenylhydrazinylidene)naphthalene‐1,3‐disulfonato]sodium(I) sesquihydrate, (SDH₂)[Na(OG)(H₂O)₄]·1.5H₂O. The [Na(OG)(H₂O)₄]₂ dimers have antiparallel naphthyl ring structures joined through two Na centres that bond to the hydrazone anions through the O atoms of the ketone and sulfonate substituents. The structures of the salts formed on reaction of SDH with 2‐aminopyridine and ethanolamine are also presented as 2‐aminopyridinium 4‐[(pyrimidin‐2‐ylazanidyl)sulfonyl]aniline, [C₅H₇N₂][SD], (V), and ethanolaminium 4‐[(pyrimidin‐2‐ylazanidyl)sulfonyl]aniline monohydrate, [HOCH₂CH₂NH₃][SD]·H₂O, (VI), respectively. Structure (V) features a heterodimeric R₂²(8) hydrogen‐bond motif between the cation and the anion, whilst structure (VI) has a tetrameric core of two cations linked by a central R₂²(10) hydrogen‐bonded motif which supports two anions linked to this core by R₃³(8) motifs.     

Self-assembly and crystal structure of a three-dimensional copper(II) complex

A copper(II) complex of a sulfonate derivative of chrysin, 5,7-bihydroxyflavone-6-sulfonate, Cu(C₁₅H₈O₇S)(3H₂O), has been prepared. The complex was characterized by elemental analysis, spectroscopic measurements and single-crystal X-ray diffraction studies. It crystallizes in the monoclinic space group C2/c, with a?=?16.036(18), b?=?6.944(8), c?=?28.03(3)?Å, β?=?94.463(17)°, V?=?3112(6)?ų, Z?=?8. In the complex, Cu(II) is five-coordinate and all donors are oxygen atoms. Hydrogen bonds and π–π stacking interactions in the crystal lead to the formation of a three-dimensional supramolecular motif.     

Dihydroazulene-Boron Subphthalocyanine Conjugates with Oligo(phenyleneethynylene) Bridging Unit: Photoswitchable Fluorophores

In this work, we have linked the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo-/thermoswitch and the boron subphthalocyanine (BsubPc) fluorophore via an axial oligo(phenyleneethynylene) bridging unit into new DHA-BsubPc conjugates. The objectives were to elucidate the influence of BsubPc on the DHA/VHF switching reactions and the influence of DHA/VHF on the BsubPc fluorescence in these conjugates for which the entire axial substituent connected to boron comprises one large, conjugated scaffold. We present the synthesis and properties of DHA-BsubPc conjugates with varying peripheral substituents on the BsubPc core, being either unsubstituted (H₁₂BsubPc) or partially fluorinated (F₆BsubPc). Fluorination of the BsubPc core provided a remarkable increase in the reversibility of the DHA-VHF interconversions promoted by light and heat, respectively, and accompanied by on/off switching of the BsubPc fluorescence. Synthetically, the units were connected using Sonogashira coupling reactions of suitable acetylenic building blocks.     

N‐Heterocyclic Carbene Analogues of Thiele and Chichibabin Hydrocarbons

Stable N‐heterocyclic carbene analogues of Thiele and Chichibabin hydrocarbons, [(IPr)(C₆H₄)(IPr)] and [(IPr)(C₆H₄)₂(IPr)] ( 4 and 5 , respectively; IPr=C{N(2,6‐iPr₂C₆H₃)}₂CHCH), are reported. In a nickel‐catalyzed double carbenylation of 1,4‐Br₂C₆H₄ and 4,4′‐Br₂(C₆H₄)₂ with IPr ( 1 ), [(IPr)(C₆H₄)(IPr)](Br)₂ ( 2 ) and [(IPr)(C₆H₄)₂(IPr)](Br)₂ ( 3 ) were generated, which respectively afforded 4 and 5 as crystalline solids upon reduction with KC₈. Experimental and computational studies support the semiquinoidal nature of 5 with a small singlet?triplet energy gap ΔE_S?T of 10.7 kcal mol^?1, whereas 4 features more quinoidal character with a rather large ΔE_S?T of 25.6 kcal mol^?1. In view of the low ΔE_S?T, 4 and 5 may be described as biradicaloids. Moreover, 5 has considerable (41 %) diradical character.     

The first square‐planar copper(II) 1:2 complex with differently coordinated 2‐hydroxybenzaldehyde 4‐allylthiosemicarbazone ligands

The title compound, [(Z)‐4‐allyl‐2‐(2‐hydroxybenzylidene)thiosemicarbazide‐κS][(E)‐4‐allyl‐1‐(2‐oxidobenzylidene)thiosemicarbazidato‐κ³O,N¹,S]copper(II) monohydrate, [Cu(C₁₁H₁₁N₃OS)(C₁₁H₁₃N₃OS)]·H₂O, crystallized as a rotational twin in the monoclinic crystal system (space group Cc) with two formula unit (Z′ = 2) in the asymmetric unit, one of which contains an allyl substituent disordered over two positions. The Cu^II atom exhibits a distorted square‐planar geometry involving two differently coordinated thiosemicarbazone ligands. One ligand is bonded to the Cu^II atom in a tridentate manner via the phenolate O, azomethine N and thioamide S atoms, while the other coordinates in a monodentate manner via the S atom only. The complex is stabilized by an intramolecular hydrogen bond, which creates a six‐membered pseudo‐chelate metalla‐ring. The structure analysis indicates the presence of the E isomer for the tridentate ligand and the Z isomer for the monodentate ligand. The crystal structure contains a three‐dimensional network built from intermolecular O—H...O, N—H...O, O—H...N and N—H...S hydrogen bonds.     

The first bipodal thio­carbamic acid ester,O,O′‐diethyl N,N′‐(p‐phenylene­di­carbonyl)­bis(­thio­carbamate)

The title compound, C₁₄H₁₆N₂O₄S₂, is the first reported X‐ray crystallographic structure determination of a bipodal O‐alkyl N‐benzoyl­thio­carbamate. This compound crystallizes in a cis‐S,O orientation (Z,Z′ configuration), with the two S/O moieties anti relative to one another, as indicated by the twofold rotation axis located at the center of the benzene ring.     

Between MOFs and molecules: organolead(IV) compounds with chain structures

Organolead compounds are of interest mainly as catalysts and organolead halides have proved to be very efficient materials for solar cells. Two organolead(IV) dimethylarsinates, namely catena‐poly[[triphenyllead(IV)]‐μ‐chlorido‐[triphenyllead(IV)]‐μ‐dimethylarsinato‐κ²O:O′], [Pb₂(C₆H₅)₆(C₂H₆AsO₂)Cl]_n or [(Ph₃Pb)₂Cl(O₂AsMe₂)], ( 1 ), and poly[chlorido(μ₃‐dimethylarsinato‐κ³O:O,O′:O′)diphenyllead(IV)], [Pb(C₆H₅)₂(C₂H₆AsO₂)Cl]_n or [(Ph₂ClPb)(O₂AsMe₂)], ( 2 ), together with the triphenyllead(IV) diphenylphosphinate catena‐poly[[triphenyllead(IV)]‐μ‐diphenylphosphinato‐κ²O:O′], [Pb(C₆H₅)₃(C₁₂H₁₀O₂P)]_n or [(Ph₃Pb)(O₂PPh₂)], ( 3 ), have been synthesized and characterized by single‐crystal X‐ray diffraction, IR spectroscopy and mass spectrometry. In ( 1 ), a chain structure was found with alternating chloride and Pb—O—As—O—Pb arsinate bridges between five‐coordinate Pb^IV atoms. In ( 2 ), bidentate and chelate‐like bonded dimethylarsinate ligands form double chains with heptacoordinated Pb^IV atoms. In ( 3 ), a pentacoordinated Pb^IV atom is connected by Pb—O—P—O—Pb phosphinate bridges to form a linear chain. Obviously, the steric demand of the phenyl ligands at Pb^IV reduces the possibility of interconnections via polydentate ligands to one dimension only. Thus, no metal–organic frameworks (MOF) are formed but instead various chain structures are observed.     

Two N‐ortho‐nitro­benzene­sulfonyl α,α‐disubstituted amino acid adducts

The carboxy group of 2‐methyl‐N‐[(2‐nitrophenyl)sulfonyl]­alanine, C₁₀H₁₂N₂O₆S, forms centrosymmetric hydrogen‐bonded dimers with an O?O distance of 2.629 (2) Å and an intramolecular N—H?O(nitro) hydrogen bond N?O distance of 2.823 (2) Å. 1‐[(2‐Nitro­phenyl)­sulfonyl­amino]­cyclo­hexane­carboxyl­ic acid, C₁₃H₁₆N₂O₆S, has Z′ = 2 and forms similar interactions.     

(Z)‐2‐Methylbuten‐1‐yl(aryl)iodonium trifluoromethanesulfonates containing electron‐withdrawing groups on the aryl moiety

The crystal structures of [(Z)‐2‐methyl­but‐1‐en‐1‐yl]­[4‐(tri­fluoro­methyl)­phenyl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₂H₁₃F₃I⁺·CF₃O₃S^?, (I), (3,5‐di­chloro­phenyl)­[(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₁H₁₂­Cl₂I⁺·CF₃O₃S^?, (II), and bis{[3,5‐bis­(tri­fluoro­methyl)­phenyl][(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium} bis­(tri­fluoro­methane­sulfonate) di­chloro­methane solvate, 2C₁₃H₁₂F₆I⁺·­2CF₃­O₃S^?·CH₂Cl₂, (III), are described. Neither simple acyclic β,β‐di­alkyl‐substituted alkenyl­(aryl)­idonium salts nor a series containing electron‐deficient aryl rings have been described prior to this work. Compounds (I)–(III) were found to have distorted square‐planar geometries, with each I atom interacting with two tri­fluoro­methane­sulfonate counter‐ions.     

Soft scorpionate coordination at alkali metals

Reported here are the single‐crystal X‐ray structure analyses of bis‐μ‐methanol‐κ⁴O:O‐bis{[hydrotris(3‐phenyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato‐κ³H,S,S′](methanol‐κO)sodium(I)}, [Na₂(C₂₇H₂₂BN₆S₃)₂(CH₄O)₄] (NaTm^Ph), bis‐μ‐methanol‐κ⁴O:O‐bis{[hydrotris(3‐isopropyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato‐κ³H,S,S′](methanol‐κO)sodium(I)}–diethyl ether–methanol (1/0.3333/0.0833), [Na₂(C₁₈H₂₈BN₆S₃)₂(CH₄O)₄]·0.3333C₄H₁₀O·0.0833CH₃OH (NaTm^iPr), and a novel anhydrous form of sodium hydrotris(methylthioimidazolyl)borate, poly[[μ‐hydrotris(3‐methyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato]sodium(I)], [Na(C₁₂H₁₆BN₆S₃)] ([NaTm^Me]_n). NaTm^iPr and NaTm^Ph have similar dimeric molecular structures with κ³H,S,S′‐bonding, but they differ in that NaTm^Ph is crystallographically centrosymmetric (Z′ = 0.5) while NaTm^iPr contains one crystallographically centrosymmetric dimer and one dimer positioned on a general position (Z′ = 1.5). [NaTm^Me]_n is a one‐dimensional coordination polymer that extends along the a direction and which contains a hitherto unseen side‐on η²‐C=S‐to‐Na bond type. An overview of the structural preferences of alkali metal soft scorpionate complexes is presented. This analysis suggests that these thione‐based ligands will continue to be a rich source of interesting alkali metal motifs worthy of isolation and characterization.     

Two nickel(II) bis[(pyridin‐2‐yl)methyl]amine complexes with homophthalic and benzene‐1,2,4,5‐tetracarboxylic acids

Two new Ni^II complexes involving the ancillary ligand bis[(pyridin‐2‐yl)methyl]amine (bpma) and two different carboxylate ligands, i.e. homophthalate [hph; systematic name: 2‐(2‐carboxylatophenyl)acetate] and benzene‐1,2,4,5‐tetracarboxylate (btc), namely catena‐poly[[aqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)]‐μ‐2‐(2‐carboxylatophenyl)aceteto‐κ²O:O′], [Ni(C₉H₆O₄)(C₁₂H₁₃N₃)(H₂O)]_n, and (μ‐benzene‐1,2,4,5‐tetracarboxylato‐κ⁴O¹,O²:O⁴,O⁵)bis(aqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)) bis(triaqua{bis[(pyridin‐2‐yl)methyl]amine‐κ³N,N′,N′′}nickel(II)) benzene‐1,2,4,5‐tetracarboxylate hexahydrate, [Ni₂(C₁₀H₂O₈)(C₁₂H₁₃N₃)₂(H₂O)₂]·[Ni(C₁₂H₁₃N₃)(H₂O)₃]₂(C₁₀H₂O₈)·6H₂O, (II), are presented. Compound (I) is a one‐dimensional polymer with hph acting as a bridging ligand and with the chains linked by weak C—H...O interactions. The structure of compound (II) is much more complex, with two independent Ni^II centres having different environments, one of them as part of centrosymmetric [Ni(bpma)(H₂O)]₂(btc) dinuclear complexes and the other in mononuclear [Ni(bpma)(H₂O)₃]²⁺ cations which (in a 2:1 ratio) provide charge balance for btc⁴⁻ anions. A profuse hydrogen‐bonding scheme, where both coordinated and crystal water molecules play a crucial role, provides the supramolecular linkage of the different groups.     

Rotationally‐hindered furyl fulgides

Fulgides are a representative class of photochromic organic molecules which exhibit several interesting properties for diverse applications in fields such as data storage or high‐resolution spectroscopy. The crystal structures of three furyl fulgides with different steric constraints were determined and for two of the compounds both the E and Z isomer structures were defined. The compounds are 3‐[(E)‐1,3‐dimethyl‐4,5,6,7‐tetrahydro‐2‐benzofuran‐4‐ylidene]‐4‐isopropylidenetetrahydrofuran‐2,5‐dione, C₁₇H₁₈O₄, (I‐E), 3‐[(E)‐1,3‐dimethyl‐5,6,7,8‐tetrahydro‐4H‐cyclohepta[c]furan‐4‐ylidene]‐4‐isopropylidenetetrahydrofuran‐2,5‐dione, C₁₈H₂₀O₄, (II‐E), and the Z isomer, (II‐Z), and 3‐isopropylidene‐4‐[(E)‐1‐(5‐methoxy‐2‐methyl‐1‐benzofuran‐3‐yl)ethylidene]tetrahydrofuran‐2,5‐dione, C₁₉H₁₈O₅, (III‐E), with two molecules in the asymmetric unit, and the Z isomer, (III‐Z). The structures of the E and Z isomers show only little differences in the bond lengths and angles inside the hexatriene unit. Because of the strained geometry there are deviations in the torsion angles. Furthermore, small differences in the distances between the bond‐forming C atoms in the electrocyclization process give no explanation for the unequal photochromic behaviour.     

A liquid crystal derived from ­ruthenium(II,III) and a long‐chain carboxylate

The title compound, catena‐poly[[tetrakis(μ‐decanoato‐κ²O:O′)diruthenium(II,III)(Ru—Ru)]‐μ‐octanesulfonato‐κ²O:O′], [Ru₂(C₁₀H₁₉O₂)₄(C₈H₁₇O₃S)], is an octane­sulfonate derivative of the mixed‐valence complex diruthenium tetradecanoate. The equatorial carboxyl­ate ligands are bidentate, bridging two Ru atoms to form a dinuclear structure. Each of the two independent dinuclear metal complexes in the asymmetric unit is located at an inversion centre. The octane­sulfonate anion bridges the two dinuclear units through axial coordination. The alkyl chains of the carboxyl­ate and sulfonate ligands are arranged in a parallel manner. The global structure can be seen as infinite chains of polar moieties separated by a double layer of non‐polar alkyl groups, without interdigitation of the alkyl chains.     

Electrochemical properties of a cobalt(II) complex with sulfadiazine and 1,3‐bis(pyridin‐4‐yl)propane

catena‐Poly[[bis{4‐[(pyrimidin‐2‐ylazanidyl)sulfonyl]aniline}cobalt(II)]‐bis[μ‐1,3‐bis(pyridin‐4‐yl)propane]], [Co(C₁₀H₈N₄O₄S₂)₂(C₁₃H₁₄N₂)]_n or [Co(L)₂(bpp)]_n, crystallizes as a one‐dimensional polymeric structure which is further stabilized by intermolecular hydrogen bonding. The refined Flack parameter, −0.001 (10), indicates that the model represents the correct absolute structure. Investigation of the thermal stability shows that the complex is stable up to 543 K. The structure is of interest with respect to its electrochemical properties in the reduction reaction of H₂O₂ to H₂O.     

The first crystal structure of an alkaline metal salt of thioglucose: potassium 1‐thio‐β‐D‐glucoside monohydrate

In the crystal structure of the title hydrated salt, poly[(μ₂‐aqua)(μ₄‐1‐sulfido‐β‐D‐glucoside)potassium], [K(C₆H₁₁O₅S)(H₂O)]_n or K⁺·C₆H₁₁O₅S⁻·H₂O, each thioglucoside anion coordinates to four K⁺ cations through three of its four hydroxy groups, forming a three‐dimensional polymeric structure. The negatively charged thiolate group in each anion does not form an efficient coordination bond with a K⁺ cation, but forms intermolecular hydrogen bonds with four hydroxy groups, which appears to sustain the polymeric structure. The Cremer–Pople parameters for the thioglucoside ligand (Q = 0.575, θ = 8.233° and ϕ = 353.773°) indicate a slight distortion of the pyranose ring.     

Crystal Structure and Photoluminescence of a Tetranuclear Cadmium Complex

A novel tetranuclear cadmium complex ([{Cd(C₁₅H₈O₇S)(H₂O)(DMSO)}₃{Cd(C₁₅H₈O₇S)(H₂O)₂}]·3DMSO·H₂O) was obtained by the self‐assembly of Cd(II) with 5,7‐dihydroxyflavone‐6‐sulfonate. The complex was characterized by ¹H NMR, IR, elemental analysis and X‐ray single‐crystal diffraction studies. It crystallizes in triclinic, space group $ P {\bar 1} $ . In the complex, the chelate atoms of Cd(II) are all from oxygen. Four Cd(II) are connected via the carbonyl and 5‐hydroxyanion of four ligands and form an approximate square. Four ligands locate at two sides of the square, and two of them at the same side are almost parallel and exist aromatic π‐π stacking. Ligands on the opposite side of the square are nearly perpendicular. The result of the luminescent studies indicated that the solid of the complex shwed photoluminescent properties because of a combination of coordination, hydrogen bonding and π‐π stacking interaction in the molecule structure. The complex emits green fluorescence (λ_em=496 nm) when it is excited at the wavelength of 440 nm.