Supramolecular Motifs in s-Block Metal-Bound Sulfonated Monoazo Dyes, Part 1: Structural Class Controlled by Cation Type and Modulated by Sulfonate Aryl Ring Position

Biosolids, an important route for transporting poly- and perfluoroalkyl substances from wastewater treatment plants into the environment: A systematic review

The pervasive presence of poly- and perfluoroalkyl substances (PFAS) in diverse products has led to their introduction into wastewater systems, making wastewater treatment plants (WWTPs) significant PFAS contributors to the environment. Despite WWTPs' efforts to mitigate PFAS impact through physicochemical and biological means, concerns persist regarding PFAS retention in generated biosolids. While numerous review studies have explored the fate of these compounds within WWTPs, no study has critically reviewed their presence, transformation mechanisms, and partitioning within the sludge. Therefore, the current study has been specifically designed to investigate these aspects. Studies show variations in PFAS concentrations across WWTPs, highlighting the importance of aqueous-to-solid partitioning, with sludge from PFOS and PFOA-rich wastewater showing higher concentrations. Research suggests biological mechanisms such as cytochrome P450 monooxygenase, transamine metabolism, and beta-oxidation are involved in PFAS biotransformation, though the effects of precursor changes require further study. Carbon chain length significantly affects PFAS partitioning, with longer chains leading to greater adsorption in sludge. The wastewater's organic and inorganic content is crucial for PFAS adsorption; for instance, higher sludge protein content and divalent cations like calcium and magnesium promote adsorption, while monovalent cations like sodium impede it. In conclusion, these discoveries shed light on the complex interactions among factors affecting PFAS behavior in biosolids. They underscore the necessity for thorough considerations in managing PFAS presence and its impact on environmental systems.

Isostructural behaviour in ammonium and potassium salt forms of sulfonated azo dyes

The structures of five ammonium salt forms of monosulfonated azo dyes, derivatives of 4-(2-phenyldiazen-1-yl)benzenesulfonate, with the general formula [NH4][O3S(C6H4)NN(C6H3)RR']·XH2O [R = OH, NH2 or N(C2H4OH)2; R' = H or OH] are presented. All form simple layered structures with alternating hydrophobic (organic) and hydrophilic (cation, solvent and polar groups) layers. To assess for isostructural behaviour of the ammonium cation with M+ ions, the packing of these structures is compared with literature examples. To aid this comparison, the corresponding structures of four potassium salt forms of the monosulfonated azo dyes are also presented herein. Of the five ammonium salts it is found that three have isostructural equivalents. In two cases this equivalent is a potassium salt form and in one case it is a rubidium salt form. The isostructurality of ion packing and of unit-cell symmetry and dimensions tolerates cases where the ammonium ions form somewhat different interaction types with coformer species than do the potassium or rubidium ions. No sodium salt forms are found to be isostructural with any ammonium equivalent. However, similarities in the anion packing within a single hydrophobic layer are found for a group that consists of the ammonium and rubidium salt forms of one azo anion species and the sodium and silver salt forms of a different azo species.

Utilization of KOH-modified fly ash for elimination from aqueous solutions of potentially toxic metal ions

Long-term accumulation of toxic heavy metals in the environment was a potential hidden danger. High energy consumption, complicated operation and low adsorption capacity were the disadvantages of most current adsorbents. This study used one-step modification of fly ash (FA) by low-temperature melting method with KOH as the activator to generate modified fly ash (KFA) with high adsorption capacity to remove heavy metals from aqueous solutions. Various characterization results revealed a destruction that occurred on the surface structure of adsorbent, 12 times increase in specific surface area, and metal ions were successfully adsorbed onto KFA surface. Furthermore, adsorption proceeded most favorably at pH of 5, the presence of ionic strength and co-existing cations significantly influenced the adsorption effects. The description of adsorption data was more suitable by pseudo-second-order kinetics and Langmuir isotherm models. And in single system at 25 °C, for Pb(II), Cu(II), and Cd (II), the q_m were 337.41, 310.09 and 125.00 mg·g^-1. However, in ternary system, the q_m decreased for all three ions in the order Pb(II) > Cu(II) > Cd(II), which was different from the law in single system, and the Pb(II) adsorption was found to have a significant inhibited effect on adsorption of Cd(II) and Cu(II). The adsorption mechanisms including ion exchange, electrostatic attraction and complexation were revealed. And by exploring the bioaccessibility of absorbed heavy metals in four simulated digestive fluids, it was found that KFA could load heavy metal ions and enable their release in organisms and other aquatic environments, which provided the possibility for subsequent related studies. Therefore, KFA with low energy consumption and high adsorption capacity is equipped a prospective development space on removing heavy metals from wastewater.

Effect and mechanisms of synthesis conditions on the cadmium adsorption capacity of modified fly ash

In this study, modified coal fly ash (NMFA) was prepared by sodium hydroxide (NaOH) with low-temperature hydrothermal method. The differences of the ash to alkali mass ratio (5:3, 5:4, 5:5, 5:6), calcination temperature (100 ℃, 200 ℃, 300 ℃), and calcination time (1 h, 3 h, 5 h) were investigated. The adsorption experiments obtained the optimal result with the ash to base ratio of 5:5, calcination temperature of 200 ℃, and calcination time of 3 h, adsorbing 90.27 mg/g of Cd²⁺. The characterization results (SEM-EDS, FTIR, XRD, and XPS) also confirmed the effective adsorption of Cd²⁺ by NMFA. The functional groups of Si-O, Al-O, and Fe-O played an important role in Cd²⁺ removal. Meanwhile, the influences of dosage, different pH, and co-existing cations were also investigated. Quasi-secondary adsorption kinetics and Langmuir isotherm model were also referred to the Cd²⁺ adsorption by NMFA. Therefore, the good adsorption of NMFA-3 on Cd²⁺ provided new ideas for the safe utilization of fly ash and heavy metal purification in wastewater.

First crystal structure of a Pigment Red 52 compound: DMSO solvate hydrate of the monosodium salt

Pigment Red 52, Na2[C18H11ClN2O6S], is an industrially produced hydrazone-laked pigment. It serves as an inter-mediate in the synthesis of the corresponding Ca2+ and Mn2+ salts, which are used commercially for printing inks and lacquers. Hitherto, no crystal structure of any salt of Pigment Red 52 is known. Now, single crystals have been obtained of a dimethyl sulfoxide solvate hydrate of the monosodium salt of Pigment Red 52, namely, monosodium 2-[2-(3-carb-oxy-2-oxo-1,2-di-hydro-naphthalen-1-yl-idene)hydrazin-1-yl]-5-chloro-4-methyl-benz-ene-sulfonate dimethyl sulfoxide monosolvate monohydrate, Na+·C18H12ClN2O6S-·H2O·C2H6OS, obtained from in-house synthesized Pigment Red 52. The crystal structure was determined by single-crystal X-ray diffraction at 173 K. In this monosodium salt, the SO3 - group is deprotonated, whereas the COOH group is protonated. The residues form chains via ionic inter-actions and hydrogen bonds. The chains are arranged in polar/non-polar double layers.

Enhanced adsorption of copper ions by phosphoric acid-modified Paeonia ostii seed coats

Novel adsorbent, phosphoric acid-modified Paeonia ostii seed coats (PA-PSC) were successfully prepared by low-temperature pyrolysis to effectively remove Cu(II) from aqueous solution. The results revealed that equilibrium adsorption capacity (q_e) of PA-PSC for Cu(II) was notably enhanced up to 4-folds compared with the raw PSC. FT-IR and XPS analyses suggested that the adsorption of Cu(II) by PA-PSC was primarily ascribed to electrostatic forces and complexing effects. Besides, equilibrium and kinetic studies demonstrated that Freundlich and pseudo-second-order models were the actually fairly good approximations of Cu(II) adsorption. Thermodynamic analysis revealed that the adsorption of Cu(II) onto PA-PSC was a chemical, endothermic, and spontaneous process. Lastly, reusability study further confirmed the applicability of PA-PSC as a promising adsorbent for removing Cu(II) from aqueous solution.

Structures of five salt forms of disulfonated monoazo dyes

The structures of five s-block metal salt forms of three disulfonated monoazo dyes are presented. These are poly[di-μ-aqua-diaqua[μ4-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)]disodium(I)], [Na2(C12H8N2O6S2)(H2O)4]n, (I), catena-poly[[tetraaquacalcium(II)]-μ-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)], [Ca(C12H8N2O6S2)(H2O)4]n, (II), catena-poly[[[diaquacalcium(II)]-μ-2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] dihydrate], {[Na(C12H10N3O6S2)(H2O)2]·2H2O}n, (III), hexaaquamagnesium bis[2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] octahydrate, [Mg(H2O)6](C12H10N3O6S2)2·8H2O, (IV), and poly[[{μ2-4-[2-(4-amino-2-methyl-5-methoxyphenyl)diazen-1-yl]benzene-1,3-disulfonato}di-μ-aqua-diaquabarium(II)] dihydrate], {[Ba(C14H13N3O7S2)(H2O)4]·2H2O}n, (V). Compound (III) is that obtained on crystallizing the commercial dyestuff Acid Yellow 9 [74543-21-8]. The Mg species is a solvent-separated ion-pair structure and the others are all coordination polymers with bonds from the metal atoms to sulfonate groups. Compound (I) is a three-dimensional coordination polymer, (V) is a two-dimensional coordination polymer and both (II) and (III) are one-dimensional coordination polymers. The coordination behaviour of the azo ligands and the water ligands, the dimensionality of the coordination polymers and the overall packing motifs of these five structures are contrasted to those of monosulfonate monoazo congers. It is found that (I) and (II) adopt similar structural types to those of monosulfonate species but that the other three structures do not.

Two monosodium salt hydrates of Colour Index Pigment Red 48

We report herein the crystal structures of a monohydrate of Colour Index Pigment Red 48 (P.R.48) (systematic name: monosodium 2-{2-[3-carboxy-2-oxo-1,2-dihydronaphthalen-1-ylidene]hydrazin-1-yl}-4-chloro-5-methylbenzenesulfonate monohydrate), Na⁺·C₁₈H₁₂ClO₆S^-·H₂O, and a dihydrate, Na⁺·C₁₈H₁₂ClO₆S^-·2H₂O. The two monosodium salt hydrates of P.R.48 were obtained from in-house synthesized P.R.48. Both have monoclinic (P2₁/c) symmetry at 173 K. The crystal packing of both crystal structures shows a layer arrangement whereby N-H...O and O-H...O hydrogen bonds are formed.

Monosulfonated Azo Dyes: A Crystallographic Study of the Molecular Structures of the Free Acid, Anionic and Dianionic Forms

Crystallographic studies of monosulfonated azo dyes have concentrated on the salt forms that contain the azo anion. Here we present a study that compares the structures of these anions with protonated free acid forms and with doubly deprotonated dianion forms. To this end, the new single crystal diffraction structures of 13 systematically related free acid forms of monosulfonated azo dyes are presented, together with three new structures of doubly deprotonated forms and two new structures of Na salt forms of azo anions. No structures of dideprotonated monosulfonated azo dyes have previously been reported and this paper also reports the first crystal structure of an azo dye with a hydronium cation. The geometries of the free acid, anion and dianion forms are compared to literature equivalents. It is shown that protonation of the azo bond gives predictable bond lengthening and shortening, which is of a greater magnitude than similar effects caused by azo-hydrazone tautomerisation, or the smaller again effects caused by the resonance electron donation from O or N based substituents. The dianion containing structures have twisted dianion geometries that can be understood based on the resonance effects of the phenoxide groups and upon the needs to bond to a relatively high number of metal cations.

Potential of removing Cd(II) and Pb(II) from contaminated water using a newly modified fly ash

Modified fly ash was prepared through low-temperature roasting method using NaOH as activator. The techniques of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS) and the X-ray diffraction (XRD) were introduced to analyze the chemical and physical performance of samples, respectively. It was found that a significant improvements in activity and specific surface area of adsorbent. This work systematically reported the uptake performances of modified materials for single and two mixed toxic cations Pb(II) and Cd(II). The results unveiled that pseudo-second-order model was suitable to analyze the adsorption process. The adsorption process were better fitted by Langmuir model and the maximum uptake capacities were 126.55 and 56.31 mg g^-1 for Pb(II) and Cd(II) in single system at 298 K, respectively. Additionally, in mixed solution, the maximum uptake capacity reduced to 120.48 and 36.10 mg g^-1 under the same adsorption conditions. Competitive adsorption results demonstrated that adsorption ability was restricted by other metal ions, as while as, the binding affinity of two cations followed the order of Pb(II)>Cd(II). Meanwhile, the co-existed cations as Ca(II), Mg(II) Na(I) and K(I) had antagonistic effects on the uptake of Cd(II) and Pb(II). The results indicate that the modified fly ash was a low-cost and effective adsorbent for the cleaning up metal ions in wastewater, which has a promising application prospect.

Metal–organic architectures driven by a multifunctional 6-aminouracil spacer: structures, noncovalent interactions, and conductivity

Three new coordination polymers were assembled from a multifunctional 6-aminouracil building block and their structural features & functional properties were investigated.

Nucleobase carbonyl groups are poor Mg2+ inner-sphere binders but excellent monovalent ion binders-a critical PDB survey

Precise knowledge of Mg²⁺ inner-sphere binding site properties is vital for understanding the structure and function of nucleic acid systems. Unfortunately, the PDB, which represents the main source of Mg²⁺ binding sites, contains a substantial number of assignment issues that blur our understanding of the functions of these ions. Here, following a previous study devoted to Mg²⁺ binding to nucleobase nitrogens, we surveyed nucleic acid X-ray structures from the PDB with resolutions ≤2.9 Å to classify the Mg²⁺ inner-sphere binding patterns to nucleotide carbonyl, ribose hydroxyl, cyclic ether, and phosphodiester oxygen atoms. From this classification, we derived a set of "prior-knowledge" nucleobase Mg²⁺ binding sites. We report that crystallographic examples of trustworthy nucleobase Mg²⁺ binding sites are fewer than expected since many of those are associated with misidentified Na⁺ or K⁺ We also emphasize that binding of Na⁺ and K⁺ to nucleic acids is much more frequent than anticipated. Overall, we provide evidence derived from X-ray structures that nucleobases are poor inner-sphere binders for Mg²⁺ but good binders for monovalent ions. Based on strict stereochemical criteria, we propose an extended set of guidelines designed to help in the assignment and validation of ions directly contacting nucleobase and ribose atoms. These guidelines should help in the interpretation of X-ray and cryo-EM solvent density maps. When borderline Mg²⁺ stereochemistry is observed, alternative placement of Na⁺, K⁺, or Ca²⁺ must be considered. We also critically examine the use of lanthanides (Yb³⁺, Tb³⁺) as Mg²⁺ substitutes in crystallography experiments.

(E)-1-(4-Fluorophenyl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium

In the title zwitterion, C16H11FN2O, which belongs to the family of azo dyes, the dihedral angle between the benzene ring and the naphthalene ring system is 15.33 (7)° and an intramolecular N—H...O hydrogen bond closes anS(6) ring. In the crystal, inversion dimers linked by weak C—H...O hydrogen bonds generateR22(16) loops. Aromatic π–π stacking [centroid–centroid distance = 3.585 (11) Å] is also observed.

Ag(i) bipyridyl coordination polymers containing functional anions

Traditional polymeric silver–bipyridyl complexes with the non-traditional twist of anions from functional organic molecules; diclofenac, salicylic acid and azo dyes.

Carboxylate-phenolate tautomerism in 5-[(nitrophenyl)diazenyl]salicylate anions

Aryldiazenyl derivatives of salicylic acid and their salts are used as dyes. In these structures, the carboxylate groups are engaged in short contacts with the cations and in hydrogen bonds with water molecules, if present. If both O atoms of the carboxylate group take part in such interactions, the negative charge is delocalized over the two atoms. In the absence of hydrogen bonds and contacts with cations, the negative charge is localized on one of the O atoms. In the crystal structures of tetramethylammonium 2-hydroxy-5-[(E)-(4-nitrophenyl)diazenyl]benzoate and tetramethylammonium 2-hydroxy-5-[(E)-(2-nitrophenyl)diazenyl]benzoate, both C4H12N(+)·C13H8N3O5(-), all the interactions between the cations and anions are weak, and their effect on the geometry of the anions is negligible. Under these conditions, the 2-nitro-substituted anion is an almost pure phenol-carboxylate tautomer, whereas in the 4-nitro-substituted anion, the phenolic H atom is shifted towards the carboxylate group, and thus the structure of this anion is intermediate between the phenol-carboxylate and phenolate-carboxylic acid tautomeric forms. The probable formation of such an intermediate form is supported by quantum chemical calculations. Being the characteristic feature of this form, a short distance between the phenolic and carboxylate O atoms is observed in the 4-nitro-substituted anion, as well as in the structures of some 3,5-dinitrosalicylates reported in the literature.

Influence of cations on the partition behavior of perfluoroheptanoate (PFHpA) and perfluorohexanesulfonate (PFHxS) on wastewater sludge

The effects of different cations on the sorption behavior of PFHpA and PFHxS on two types of sludge were investigated in this study. The sodium and potassium ions did not significantly affect PFHpA and PFHxS sorption on different sludge. For calcium and magnesium, the sorption amount of PFAS increased with calcium and magnesium concentration increasing from 1 to 30 mM and then decreased with those increasing from 30 to 100 mM. The sorption level of PFHxS or PFHpA greatly increased with increasing Al3+ and Fe3+ cation concentrations due to the strong sorption and coagulation effects by the formation of aluminum hydroxide (or ferric hydroxide) colloids or precipitates. After the organics in sludge has been removed by thermal treatment, the PFAS sorption on sludge was greatly reduced. Such finding indicated that sorption to organic matter is more important for anionic PFASs than adsorption to mineral surfaces. However, due to the higher content of biological organics, a secondary activated sludge has higher affinity toward PFAS species than chemically enhanced primary treatment sludge. It indicated that the organic types in sludge were also crucial to the sorption levels of PFASs by sludge.

Amino modification of biochar for enhanced adsorption of copper ions from synthetic wastewater

Biochar was modified as a high efficient and selective absorbent for copper ions (Cu(II)) by nitration and reduction. Results of X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) analyses indicated that the amino groups were chemically bound to the functional groups on the biochar surface. Kinetics, thermal dynamics, and adsorption and desorption of Cu(II) in fixed-bed were investigated. The results demonstrated that the amino-modified biochar exhibited excellent adsorption performance for Cu(II). The adsorption capacity and bed volume of the modified biochar are five- and eight- folds of the pristine biochar, respectively. The Cu(II) combined with the amino groups through strong complexation based on the comparison of XPS and ATR-FTIR analyses before and after adsorption, which endows it with the high pH stability and ion selectivity.

Cation radii induced structural variation in fluorescent alkaline earth networks constructed from tautomers of a nucleobase analogue

Nucleobase tautomers and their metal complexes have attracted considerable attention due to their fascinating architectures along with wide applications. In this paper, 4,6-dihydroxypyrimidine (H(2)DHP), an analogue of uracil and thymine, was employed to react with the vital elements of alkaline earth metals in an aqueous solution and lead to the formation of four novel complexes, [Mg(HDHP)(2) (H(2)O)(4)] (1), [Ca(HDHP)(2)(H(2)O)(3)](n)·nH(2)O (2), [Sr(HDHP)(2)(H(2)O)(3)](n)·nH(2)O (3), and [Ba(HDHP)(2)(H(2)O)(2)](n)·nH(2)O (4), which have been characterized by elemental analysis, IR, TG, UV-Vis, PL, powder and single-crystal X-ray diffraction and progressively evolve from zero-dimensional (0D) mononuclear, one-dimensional (1D) zig-zag double chain, two-dimensional (2D) double layer, to a three-dimensional (3D) porous network along with the increase of cation radii. This tendency in dimensionality follows salient crystal engineering principles and can be explained by considering factors such as hard-soft acid-base principles and cation radii. The deprotonated H(2)DHP ligand exhibits four new coordination modes, namely, O-monodentate (complex 1), N,O-chelating (complexes 2 and 3), O,O-bridging (complexes 2 and 3), and κ(1)O:κ(2)O-bridging mode (complex 4). Interestingly, the structural investigation indicates that the HDHP(-) monoanion shows three unusual types of tautomers, which are essential for the diagnosis of disease and investigation of medicine. Furthermore, the four complexes exhibit strong blue emission compared to free H(2)DHP ligand at room temperature and may be potential candidates for blue fluorescent biological materials used in organisms.

42 salt forms of tyramine: structural comparison and the occurrence of hydrate formation

The single-crystal diffraction structures of 38 salt forms of the base tyramine (4-hydroxyphenethylamine) are reported for the first time. Together with literature examples, these structures are discussed with respect to cation conformation, cation packing, hydrogen bonding and hydrate formation. It is found that isostructural cation packing can occur even with structurally different anions, with different hydration states and with different hydrogen bonding. Hydrate formation is found to be more likely both (i) when there is an increase in the total number of potential hydrogen bond acceptor and donor atoms; and (ii) when the ratio of potential hydrogen bond donor to acceptor atoms is low.

Lithol Red: a systematic structural study on salts of a sulfonated azo pigment

The first systematic series of single-crystal diffraction structures of azo lake pigments is presented (Lithol Red with cations=Mg(II), Ca(II), Sr(II), Ba(II), Na(I) and Cd(II)) and includes the only known structures of non-Ca examples of these pigments. It is shown that these commercially and culturally important species show structural behaviour that can be predicted from a database of structures of related sulfonated azo dyes, a database that was specifically constructed for this purpose. Examples of the successful structural predictions from the prior understanding of the model compounds are that 1) the Mg salt is a solvent-separated ion pair, whereas the heavier alkaline-earth elements Ca, Sr and Ba form contact ion pairs, namely, low-dimensional coordination complexes; 2) all of the Lithol Red anions exist as the hydrazone tautomer and have planar geometries; and 3) the commonly observed packing mode of alternating inorganic layers and organic bilayers is as expected for an ortho-sulfonated azo species with a planar anion geometry. However, the literature database of dye structures has no predictive use for organic solvate structures, such as that of the observed Na Lithol Red DMF solvate. Interestingly, the Cd salt is isostructural with the Mg salt and not with the Ca salt. It is also observed that linked eight-membered [MOSO](2) rings are the basic coordination motif for all of the known structures of Ca, Sr and Ba salts of sulfonated azo pigments in which competing carboxylate groups are absent.

Adsorption of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) on alumina: influence of solution pH and cations

The persistent nature of perfluorochemicals (PFCs) has attracted global concern in recent years. Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) are the most commonly found PFC compounds, and thus their fate and transport play key roles in PFC distribution in the natural environment. As most solid phases in natural water contain alumina, an investigation of PFOS and PFOA adsorption behavior on alumina should prove useful in evaluating the environmental impact of this type of persistent pollutant. Systematic experiments were carried out in this study to investigate the adsorption behavior of PFOS and PFOA onto alumina. The results of adsorption kinetics on alumina show that it takes 48 h to reach equilibrium. The adsorption isotherms reveal maximum adsorption capacities of 0.252 μg/m(2) for PFOS and 0.157 μg/m(2) for PFOA at pH = 4.3, with the difference primarily due to their different functional groups. An increase in pH leads to a decrease in PFOS and PFOA adsorption on alumina, which may be attributed to the reduction in electrostatic interaction. The adsorption of both PFOS and PFOA decreases with an increase in ionic strength for all four types of cations (Na(+), K(+), Mg(2+), and Ca(2+)), due to the compression of the electrical double layer. Furthermore, the results also indicate that both Ca(2+) and Mg(2+) can form bridges with PFOA anions in solution, whereas only PFOS can be bridged by Ca(2+) due to the higher covalent nature of magnesium.

Synthesis and characterization of coordination polymers prepared from CuII and NiII cyclam perchlorate and carmosine

Reaction of [CuII(cyclam)](ClO4)2 or [NiII(cyclam)](ClO4)2 in DMF with aqueous 4-hydroxy-3-(4-sulfonato-1-naphthylazo)naphthalen-1-sulfonate disodium salt (carmoisine) yielded coordination polymers {[CuII(cyclam)](carmoisine dianion)(H2O)5}n and powder {[NiII(cyclam)](carmoisine dianion)}n, respectively (cyclam = 1,4,8,11-tetrazacyclotetradecane). They were characterized by powder X-ray diffraction, IR, Raman spectrometry and TGA.

Systematic investigation on the coordination chemistry of a sulfonated monoazo dye: ligand-dominated d- and f-block derivatives

Ten coordination compounds based on a sulfonated monoazo dye, formulated as M(H(2)O)(2)(4,4'-abs)(2) (M = Mn , Co , Cu , Zn , Cd and Pb ; 4,4'-abs = 4-aminoazobenzene-4'-sulfonic anion), Ag(4,4'-abs) (), [Ln(H(2)O)(phen)(2)(4,4'-abs)(3)].3H(2)O (Ln = Gd , Tb , and Ho ; phen = 1,10-phenanthroline), as well as the parent ligand L [(4,4'-Habs)(2).4H(2)O] and precursor NaL.HL [Na(4,4'-abs)(4,4'-Habs)] were successfully isolated. Structural analyses revealed that the structures of compounds, and vary according to the coordination geometries of the metal ions, and vary from double-strand chain structures () to a 3-D pillared-layer framework to mononuclear complexes. The double-strand chain structures of are isostructural, and are built on octahedral metal centers and double bridging 4,4'-abs ligands coordinating via terminal N- and O-donors. The silver-containing compound displays a pillared-layer structure constructed from 4.8(2) silver sulfonate nets pillared by the linear backbones of 4,4'-abs ligands. Compounds , which are also isostructural, possess mononuclear structures consisting of a metal cation, three 4,4'-abs anions, two auxiliary phen ligands, one aqua ligand and three non-coordinated water molecules. Evidence on two series of isostructural compounds indicates that structures of d- and f-block metal derivatives are dominated by the coordination mode of the ligands. The surface chemistry of compound has been investigated based on the LBL (layer-by-layer) technique. The as-synthesized multilayer films with different composite components exhibit different surface behaviours.

Poly[tris{μ(2)-4-[4-(di-methyl-amino)-phenyl-diazenyl]benzene-sulfonato}tri-dioxane-tri-sodium(I)]

The title compound, [Na₃(C₁₄H₁₄N₃O₃S)₃(C₄H₈O₂)₃]_n, is a polynuclear complex which includes, in the monomeric unit, three units of Na^I-4′-dimethyl­amino­azobenzene-4-sulfonate [known as methyl orange (MO)] and three molecules of dioxane (C₄H₈O₂). These constitute three kinds of Na^I centres, two of which are seven-coordinate while the third is five-coordinate. One of the seven-coordinate centres is coordinated by six O atoms from the sulfonate groups of four different MOs and by one O atom from dioxane. The other is coordinated by seven O atoms from the sulfonate groups of five different MOs. The five-coordinate centre is coordinated by three O atoms from the sulfonate groups of three different MOs and two O atoms from two different dioxanes. In the crystal structure, a one-dimensional polymer chain is formed along the a axis and this ensures the thermal stability of the title compound. It is also to be noted that the N=N bond lengths of the three azo groups are appreciably different [1.259 (4), 1.196 (4), and 1.253 (4) Å].

Three Guest-Including Coordination Solids from a Single Crystallization: A Discrete Cage and Open-Channel Networks from 1-D Ladders and 1-D Ribbons

A study of the coordination assemblies that result from the complexation of 1,3,5-tri(4-sulfophenyl)benzene, L3-, with copper(II) in the presence of pyridine is presented. The present results offer some insights into the subtleties of designing coordination polymers and open-channel solids. From an initial crystallization, three different single crystalline solids, 1-3, are obtained. Compounds 1 and 2 are Cu pyridyl complexes of the trianionic form of the ligand whereas compound 3 is a Cu pyridyl complex of the monoprotonated form, HL2-. Compound 1 is a discrete cage complex. Compound 2 is a 1-D ladder structure that has open channels, and compound 3 is a 1-D ribbon structure that assembles into open channels. All three complexes form from the same crystallization in a ratio of 90:9:1, and all three have the same Cu coordination sphere. The exact ratio of products can be altered by varying the Cu counterion or by the addition of methanol. Addition of hexamethylenetetramine results in the exclusive formation of a different network, 4, which is structurally almost identical to the minor product 3. Single-crystal structures of all four solids are presented along with thermal analysis and IR data for the major products. A number of insights into formation of coordination assemblies are obtained. Compound 3 is discussed as an intermediate to 2, and compounds 3 and 4 offer a design paradigm for the formation of open-channel solids from 1-D building blocks.

Assembling of Dimeric Entities of Cd(II) with 6-Mercaptopurine to Afford One-Dimensional Coordination Polymers: Synthesis and Scanning Probe Microscopy Characterization

The direct reaction between 6-mercaptopurine (6-MP) and Cd(II) under different conditions yields either [Cd2(6-MP)4(NO3)2](NO3)2 (1) or [Cd(6-MP-)2.2H2O]n (4). Compound 1 behaves as the building block of the polymer [Cd(6-MP2-)2]n[Ca(H2O)6]n (3), by deprotonation of 6-MP ligand. In the reaction of 1 to give 3, the dinuclear compound [Cd2(6-MP)4(H2O)2](NO3)4.2H2O (2) can be isolated as an intermediate. Polymers 3 and 4 convert into each other in water via deprotonation-protonation reactions. The structures of compounds 1-3 have been determined by X-ray diffraction. Given the small differences in the arrangement shown in the crystal structures of the polymer 4 and the polyanion of 3, the stabilities and energetics of the two arrangements have been examined by DFT calculations to determine the possibility of identifying new conformations of both polymers. In addition, the two polymers have been characterized on surfaces by means of AFM. The direct reaction between 6-MP and Cd(II) and the deprotonation of the polymer 4 have proven to be useful routes for the isolation of one-dimensional systems on surfaces. The development of new strategies to characterize these types of polymers on surfaces opens the possibility to perform nanoscale studies on their properties and their potential use as nanomaterials.

Microporous Metal−Organic Frameworks Formed in a Stepwise Manner from Luminescent Building Blocks

A series of trivalent lanthanides (Sm, Eu, Gd, Tb, Dy) have been complexed to the dianionic ligand, 4,4'-disulfo-2,2'-bipyridine-N,N'-dioxide, L, in a 3:1 ratio to form trianionic complex building blocks. These units were then cross-linked into a network solid by addition of BaCl2 to form mixed-metal networks of formula {Ba2(H2O)4[LnL3(H2O)2](H2O)nCl}infinity, Ln = Sm3+ (1), Eu3+ (2), Gd3+ (3), Tb3+ (4), Dy3+ (5). The networks were isostructural and contained open channels which readily absorbed and desorbed water accompanied by a spongelike shrinkage and expansion of the host. CO2 sorption measurements confirmed microporosity giving a DR surface area of 718 m2/gm and an average pore size of 6.4 A. Ligand L sensitized all the lanthanide ions with the exception of Gd3+. Studying the series of Ln complexes allowed the determination of the triplet state energy of L which is itself a new ligand for sensitization purposes. The luminescent properties of the lanthanide building blocks were retained in the porous network solid. From the luminescence data, it was possible to attribute the spongelike properties of the network to the Ba2+ coordination sphere rather than the Ln3+ center. Networks were characterized by X-ray crystallography, PXRD, DSC/TGA, water vapor and gas sorption, and luminescence spectroscopy.

Coordination Capabilities of a Novel Organic Polychlorotriphenylmethyl Monosulfonate Radical

The treatment of alpha-H-p-H-PTM (PTM = polychlorotriphenylmethane) with oleum 65% followed by deprotonation and oxidation leads to the isolation of a novel pure organic radical PTMSO3H x 3 H2O x 0.5 hexane (2). The X-ray diffraction of 2 reveals a layered structure with disordered H2O molecules between facing sulfonic acid groups. We have explored the coordination abilities of the sulfonate derivative using different metals. The treatment of 2 with mild bases yields the sulfonate radical PTMSO3Na x H2O (3). On the other hand, the new compound [Cu(py)2(H2O)4](PTMSO3)2 x 2 H2O x 2 EtOH (4) has been crystallized using Cu(II) as the metallic counterion in the presence of pyridine. The structure reveals a solvent-separated ion-pair-type compound, with no direct coordination of the metal ion with the sulfonate group, and the formation of organic layers between layers of transition metal complexes. This situation has been overcome by favoring the stabilization of the sulfonate group over the Cu(II) center by changing the pyridine ligand to cyclam. This has led to compound [Cu(cyclam)](PTMSO3)2 x 6 EtOH (5a), in which the sulfonate group acts as a monodentate axial ligand for the Cu(II) center. We have observed a single-to-single crystal rearrangement from 5a to [Cu(cyclam)](PTMSO3)2 (5b) because of the loss of the solvent of crystallization, without significant modification of the metal coordination environment. All species have been structurally and magnetically characterized, and the magnetic coupling between the organic radicals and the metal paramagnetic centers is discussed.