Mixed-Valent Stellated Cuboctahedral Cu(2,4-Imdb)-MOF for Trace Water Detection

Developing an economical and robust sensor using an earth-abundant metal-based metal–organic framework (MOF) to detect trace water content rapidly is crucial for laboratories and chemical industries. Herein, a mixed-valent chiral [{Cu+Cu32+(2,4-Imdb)3(H2O)3}·Cl]∞ MOF manifests atypical quantitative detection of a trace amount of water [0.016% (v/v)] in organic solvents. Single-crystal X-ray diffraction and time-correlated single-photon counting supported the mechanism for turn-on fluorescence

Synthesis of Imidazole-Based Functionalized Mesoionic Carbene Complexes of Palladium: Comparison of Donor Properties and Catalytic Activity toward Suzuki–Miyaura Coupling

Three different backbone-monofunctionalized imidazolium salts have been synthesized using the metal–halogen exchange procedure, and their corresponding mesoionic carbene complexes with palladium were prepared via oxidative addition without protection of the C2 position. The donor properties were evaluated with ³¹P NMR spectroscopy of the respective palladium complexes. The catalytic activity of these complexes toward Suzuki–Miyaura coupling of aryl bromides was also explored. Also, in one case, a comparison of donor properties was made with those of a “normal” carbene with similar steric bulk

Synthesis, Structure, and Coordination Chemistry of Phosphine-Functionalized Imidazole/Imidazolium Salts and Cleavage of a C–P Bond in an NHC–Phosphenium Salt using a Pd(0) Precursor

A simple method involving metal–halogen exchange reaction(s) to prepare various phosphine-functionalized imidazole/imidazolium salts and their coordination chemistry with different metal precursors has been described. Interestingly, the reaction of 1,3-dimethyl-2-(diphenylphosphino)-4-iodoimidazolium iodide (<b>6</b>) with Pd₂(dba)₃ in the presence of triphenylphosphine affords a Pd­(II)–NHC complex which involves the cleavage of a C–P bond presumably occurring via oxidative addition of Pd(0) to a C–I bond to afford an in situ generated Pd­(II) species, which subsequently reacts with another 1 equiv of <b>6</b> through the phosphine center to form an adduct followed by a dephosphinylation reaction

Backbone Thio-Functionalized Imidazol-2-ylidene–Metal Complexes: Synthesis, Structure, Electronic Properties, and Catalytic Activity

A new synthetic route to prepare imidazolium salts with heteroatom-containing functional groups at the backbone has been reported. Accordingly, the first example of a backbone bis-thiofunctionalized imidazolium salt (<b>4</b>) was prepared by sequential metal–halogen exchange reaction of 1-methyl-4,5-diiodoimidazole (<b>1</b>) followed by a quaternization reaction with methyl iodide. The metal–carbene complexes <b>6</b>, <b>8</b>, and <b>10</b> were synthesized conveniently through three different routes, namely, (a) an in situ generated carbene route, (b) a transmetalation method, and (c) direct reaction with a basic metal precursor, and structurally characterized. Subsequently the electronic properties of the newly prepared 1,3-dimethyl-4,5-bis­(phenylthio)-imidazol-2-ylidene ((SPh)₂IMe) was studied by measuring the carbonyl stretching frequency of the corresponding [Ir­{(SPh)₂IMe}­(CO)₂(Cl)] complex. In addition, the air-stable palladium–NHC complex <b>10</b> was found to be catalytically active in Suzuki–Miyaura coupling reactions of aryl bromides

Backbone Thio-Functionalized Imidazol-2-ylidene–Metal Complexes: Synthesis, Structure, Electronic Properties, and Catalytic Activity

A new synthetic route to prepare imidazolium salts with heteroatom-containing functional groups at the backbone has been reported. Accordingly, the first example of a backbone bis-thiofunctionalized imidazolium salt (<b>4</b>) was prepared by sequential metal–halogen exchange reaction of 1-methyl-4,5-diiodoimidazole (<b>1</b>) followed by a quaternization reaction with methyl iodide. The metal–carbene complexes <b>6</b>, <b>8</b>, and <b>10</b> were synthesized conveniently through three different routes, namely, (a) an in situ generated carbene route, (b) a transmetalation method, and (c) direct reaction with a basic metal precursor, and structurally characterized. Subsequently the electronic properties of the newly prepared 1,3-dimethyl-4,5-bis­(phenylthio)-imidazol-2-ylidene ((SPh)₂IMe) was studied by measuring the carbonyl stretching frequency of the corresponding [Ir­{(SPh)₂IMe}­(CO)₂(Cl)] complex. In addition, the air-stable palladium–NHC complex <b>10</b> was found to be catalytically active in Suzuki–Miyaura coupling reactions of aryl bromides

A Hexameric Hexagonal Organotin Macrocycle. Supramolecular Entrapment of an Iodide–Iodide Short Contact

A hexanuclear hexagonal organotin macrocycle [(<i>n</i>-Bu₃Sn)₆­(μ-L)₆(I^–)₂­(MeOH)₆] (<b>1</b>) was synthesized in a 1:1 reaction of (<i>n</i>-Bu₃Sn)₂O and 4,5-dicarboxy-1,3-dimethyl-1<i>H</i>-imidazol-3-ium iodide (LH₂I). The molecular structure of <b>1</b> reveals that it is a 42-membered hexatin macrocycle possessing a <i>C</i>₃ (pseudo-<i>S</i>₆) symmetry. The alternate up–down arrangement of imidazolium units allows the molecule to assume a <i>chair</i> topology. The hexagonal packing of these macrocycles, in the solid-state, results in nanoscale one-dimensional channels which entrap two I^– ions in close proximity (∼3.7 Å) as a result of various supramolecular interactions

A Hexameric Hexagonal Organotin Macrocycle. Supramolecular Entrapment of an Iodide–Iodide Short Contact

A hexanuclear hexagonal organotin macrocycle [(<i>n</i>-Bu₃Sn)₆­(μ-L)₆(I^–)₂­(MeOH)₆] (<b>1</b>) was synthesized in a 1:1 reaction of (<i>n</i>-Bu₃Sn)₂O and 4,5-dicarboxy-1,3-dimethyl-1<i>H</i>-imidazol-3-ium iodide (LH₂I). The molecular structure of <b>1</b> reveals that it is a 42-membered hexatin macrocycle possessing a <i>C</i>₃ (pseudo-<i>S</i>₆) symmetry. The alternate up–down arrangement of imidazolium units allows the molecule to assume a <i>chair</i> topology. The hexagonal packing of these macrocycles, in the solid-state, results in nanoscale one-dimensional channels which entrap two I^– ions in close proximity (∼3.7 Å) as a result of various supramolecular interactions

Aluminum Substituted Cobalt Ferrite (Co−Al−Fe) Nano Adsorbent for Arsenic Adsorption in Aqueous Systems and Detailed Redox Behavior Study with XPS

Arsenic [As­(III) and As­(V)] adsorption on aluminum substituted cobalt ferrite (Co−Al−Fe) ternary metal oxide adsorbent is reported by means of qualitative and quantitative spectroscopy tools. IR and Raman active signals were observed around 810–920 cm^–1 band indicate different As−OH_complexed and As−O_uncomplexed stretching vibrations on to the adsorbent. The adsorption behavior of arsenic (III and V) onto these adsorbents is studied as a function of contact time, different concentrations, and pH conditions. The kinetics study on adsorption were performed to understand nature of adsorption which supports the Pseudo Second Order (PSO) model. The adsorption isotherms study indicates Freundlich type of adsorption. The maximum adsorption capacity of Co−Al−Fe adsorbent is observed around 130 and 76 mg g^–1 for As­(III) and As­(V) systems, respectively. Detailed XPS study of As 3d, Fe 2p, Co 2p, and O 1s spectra has been reported in explaining the redox behavior and ligand exchange reactions in supporting arsenic adsorption mechanism