Publications by authors named "Arnold L. Rheingold"

Ge[N(SiMe)] reacts with isocyanates but its reactivity with the related heavier congeners has not been explored. Its reaction with tertiary isothiocyanates results in the abstraction of the sulfur atom to yield a germanium(IV) dimer [((SiMe)N)GeS] in high yield. The reaction with -butylisoselenocyanate produced the related dimer [((SiMe)N)GeSe] within 5 minutes as shown using Se NMR spectroscopy.

View Article and Find Full Text PDF

A series of ruthenium complexes of formulae [RuCl(triazenide)(-cymene)] have been synthesized using as ligand a triazenide monofunctionalized with an N-heterocyclic moiety. Nuclear magnetic resonance, high resolution mass spectrometry and X-ray diffraction were used to characterize the triazenide ligands and their complexes. In addition, these ruthenium complexes catalyzed the reduction of nitrobenzene to aniline in the presence of sodium borohydride and ethanol as solvent at room temperature.

View Article and Find Full Text PDF

A series of heterobimetallic lantern complexes, [PtFe(SOCR)(pyX)] where R = Me, X = H (), X = NH (), X = SMe (); R = Ph, X = H (), X = NH (), X = SMe (), have been prepared and characterized spectroscopically. Compounds , , and are reported herein for the first time. The high-spin iron(II) sites of - have been investigated using Fe Mössbauer spectroscopy.

View Article and Find Full Text PDF

Through mechanistic work and rational design, we have developed the fastest organometallic abiotic Cys bioconjugation. As a result, the developed organometallic Au(III) bioconjugation reagents enable selective labeling of Cys moieties down to picomolar concentrations and allow for the rapid construction of complex heterostructures from peptides, proteins, and oligonucleotides. This work showcases how organometallic chemistry can be interfaced with biomolecules and lead to a range of reactivities that are largely unmatched by classical organic chemistry tools.

View Article and Find Full Text PDF

An aqueous Cu and Zn indicator is reported based on copolymerizing aminopyridine ligands and the environment-sensitive dansyl fluorophore into the responsive polymer poly(N-isopropylacrylamide) (PNIPAm). The metal ion binding creates charge and solvation that triggers PNIPAm's thermal phase transition from hydrophobic globule to hydrophilic open coil. As a basis for sensing the metal-binding, the dansyl fluorescence emission spectra provide a signal at ca.

View Article and Find Full Text PDF

The formation of amide bonds is an important process since this linkage is an essential component in proteins, pharmaceuticals, and other medicinally and biologically significant molecules. Recently, it was demonstrated that germylamines R GeNR' were useful reagents for the conversion of acid fluorides to amides. This transformation occurs readily at room temperature and has a low activation energy.

View Article and Find Full Text PDF

We report the synthesis and characterization of various compounds containing the 1,7,9-hydroxylated -dodecahydrododecaborate (BH(OH)) cluster motif. Specifically, we show how the parent compound can be synthesized on the multigram scale and further perhalogenated, leading to a new class of vertex-differentiated weakly coordinating anions. We show that a postmodification of the hydroxyl groups by alkylation affords further opportunities for tailoring these anions' stability, steric bulk, and solubility properties.

View Article and Find Full Text PDF

3-ferrocenyl-estra-1,3,5 (10)-triene-17-one (), [Fe(CH)(CHO)], crystallizes in the monoclinic space group C2. The cyclopentadienyl (Cp) rings adopt a nearly eclipsed conformation, and the Cp plane is tilted by 87.66° with respect to the substituted phenyl plane.

View Article and Find Full Text PDF

There is considerable interest in MnOH moieties, particularly in the stepwise changes in those O-H bonds in tandem with Mn oxidation state changes. The reactivity of aquo-derived ligands, {MOH}, is also heavily influenced by the electronic character of the other ligands. Despite the prevalence of oxygen coordination in biological systems, preparation of mononuclear Mn complexes of this type with all O-donors is rare.

View Article and Find Full Text PDF

Two hypervalent trifluoromethyl organobismuth complexes were prepared from commercially available chiral amines, (R)-1-cyclohexylethylamine and (1R, 2R, 3R, 5S)-(-)-isopinocampheylamine; however, only the complex from the latter amine was prepared as a single stereoisomer. Both organobismuth complexes were fully characterized by NMR spectroscopy and single-crystal X-ray crystallography, revealing that the structures were similar to previously reported complexes with a hypervalent Bi-N bond. The complexes were catalytically active in olefin difluorocarbenation with Ruppert-Prakash reagent (TMS-CF ) used as a terminal source of CF .

View Article and Find Full Text PDF

2-R-1-1,3-Benzazaphospholes (R-BAPs) are an interesting class of σP heterocycles containing P[double bond, length as m-dash]C bonds. While closely related 2-R-1,3-benzoxaphospholes (R-BOPs) have been shown to be highly photoluminescent materials depending on specific R substituents, photoluminescence of R-BAPs has been previously limited to an example having a fused carbazole ring system. Here we detail the synthesis and structural characterization of a new R-BAP (3c, R = 2,2'-dithiophene), and compare its photoluminescence against two previously reported R-BAPs (3a, R, R' = Me and 3b, R = 2-thiophene).

View Article and Find Full Text PDF

The dynamic photoluminescence properties, and potential quenching mechanisms, of -BH, 4,4'-Br--BH, and 4,4'-I--BH are investigated in solution and polymer films. UV stability studies of the neat powders show no decomposition occurring after intense 7 day light soaking. In contrast, clusters incorporated into polymer films are found to degrade into smaller borane fragments under the same irradiation conditions.

View Article and Find Full Text PDF

In order to stabilize a 10-P-3 species with symmetry and two lone pairs on the central phosphorus atom, a specialized ligand is required. Using an NCN pincer, previous efforts to enforce this planarized geometry at P resulted in the formation of a -symmetric, 10π-electron benzazaphosphole that existed as a dynamic "bell-clapper" in solution. Here, OCO pincers 1 and 2 were synthesized, operating under the hypothesis that the more electron-withdrawing oxygen donors would better stabilize the 3-center, 4-electron O-P-O bond of the 10-P-3 target and the sp-hybridized benzylic carbon atoms would prevent the formation of aromatic P-heterocycles.

View Article and Find Full Text PDF

The diagonal relationship in the periodic table between phosphorus and carbon has set an expectation that the triple-bonded diatomic diphosphorus molecule (P) should more closely mimic the attributes of acetylene (HC≡CH) rather than its group 15 congener dinitrogen (N). Although acetylene has well-documented coordination chemistry with mononuclear transition metals, coordination complexes that feature P bound to a single metal center have remained elusive. We report the isolation and x-ray crystallographic characterization of a mononuclear iron complex featuring P coordination in a side-on, η-binding mode.

View Article and Find Full Text PDF
Article Synopsis
  • Preventing spontaneous crystallization in supersaturated solutions is essential for industries like chemical, pharmaceutical, and food, but challenges persist in both lab and real-world applications.
  • The study examines how antifreeze proteins (AFPs) can hinder crystallization, focusing on D-mannitol, a sugar alcohol, and showing that insect AFP DAFP1 can completely stop its nucleation.
  • Findings reveal that AFPs work by binding to crystal-forming molecules and altering their behavior in solution, suggesting that natural polymers could be key in developing new methods to control crystallization processes.
View Article and Find Full Text PDF

Nerve gas mimic binding with Rhodamine B ethylenediamine (1) was studied in organic media. Binding of the nerve gas mimic, diethyl chlorophosphate (DCP), with the probe generated a non-fluorescent intermediate and a fluorescent product. Fluorescent and non-fluorescent products generated were identified using mass spectrometry and X-ray crystallography.

View Article and Find Full Text PDF

A bulky 1,4-di-iodobenzene having four adjacent -Bu-CH group (Ar') substituents (1) was used to prepare the di-hypervalent iodine compound 1,4-[I(OAc)]-2,3,5,6-Ar'-C (2). Despite the steric encumbrance of the iodine center by the flanking aryl substituents, compound 2 undergoes ready cyclization under mild conditions (excess CFCOOH at 55 °C, 30 min) to afford a dicyclic di-iodonium di-triflate salt 3. The single crystal structures of compounds 2 and 3 were examined and compared to the formerly characterized precursor 1.

View Article and Find Full Text PDF

Chalcogen-containing carboranes have been known for several decades and possess stable exopolyhedral B(9)-Se and B(9)-Te σ bonds despite the electron-donating ability of the B(9) vertex. While these molecules are known, little has been done to thoroughly evaluate their electrophilic and nucleophilic behavior. Herein, we report an assessment of the electrophilic reactivity of -carboranylselenyl(II), -tellurenyl(II), and -tellurenyl(IV) chlorides and establish their reactivity pattern with Grignard reagents, alkenes, alkynes, enolates, and electron-rich arenes.

View Article and Find Full Text PDF

Tetrahedral main-group compounds are normally configurationally stable, but P-epimerization of the chiral phosphiranium cations syn- or anti-[Mes*P(Me)CH CHPh][OTf] (Mes*=2,4,6-(t-Bu) C H ) occurred under mild conditions at 60 °C in CD Cl , resulting in isomerization to give a syn-enriched equilibrium mixture. Ion exchange with excess [NBu ][Δ-TRISPHAT] (Δ-TRISPHAT=Δ-P(o-C Cl O ) ) followed by chromatography on silica removed [NBu ][OTf] and gave mixtures of syn- and anti-[Mes*P(Me)CH CHPh][Δ-TRISPHAT]⋅x[NBu ][Δ-TRISPHAT]. NMR spectroscopy showed that isomerization proceeded with epimerization at P and retention at C.

View Article and Find Full Text PDF

The achievement of atomic control over the organic-inorganic interface is key to engineering electronic and spintronic properties of molecular devices. We leverage insights from inorganic chemistry to create hard-soft acid-base (HSAB) theory-derived design principles for incorporation of single molecules onto metal electrodes. A single molecule circuit is assembled via a bond between an organic backbone and an under-coordinated metal atom of the electrode surface, typically Au.

View Article and Find Full Text PDF

Tetrahydrothiophene-functionalized N,S-heterocyclic carbene palladium(II) complexes are synthesized through an unexpected rearrangement that proceeds with palladium(II) trifluoroacetate and not with palladium(II) acetate, palladium(II) bromide, or palladium(II) chloride. A series of these complexes were isolated and characterized by X-ray crystallography. The mechanism of formation of these [3.

View Article and Find Full Text PDF

A new template condensation reaction has been discovered in a mixture of Pt(II), thiobenzamide, and base. Four complexes of the general form [Pt(ctaPh)], R = CH (), H (), F ), Cl (), cta = ondensed hiomide, have been prepared under similar conditions and thoroughly characterized by H NMR and UV-vis-NIR spectroscopy, (spectro)electrochemistry, elemental analysis, and single-crystal X-ray diffraction. The ligand is redox active and can be reduced from the initial monoanion to a dianionic and then trianionic state.

View Article and Find Full Text PDF

Tetraphenylazadipyrromethenes (ADPs) are attractive near-infrared (NIR) dyes because of their simple synthesis and exceptional optical and electronic properties. The typical BF and less explored intramolecular BO coordination planarize the molecule, making them promising π-conjugated materials for organic electronic applications. However, their use has been mostly limited to vacuum-deposited devices.

View Article and Find Full Text PDF

Mixed-metal solid-state framework materials are emerging candidates for advanced applications in catalysis and chemical separations. Traditionally, the syntheses of mixed-metal framework systems rely on postsynthetic ion exchange, metalloligands, or metal-deposition techniques for the incorporation of a second metal within a framework material. However, these methods are often incompatible with the incorporation of low-valent metal centers, which preferentially bind to electronically "soft" ligands according to the tenets of hard/soft acid/base theory.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers investigated the magnetic properties of two polymorphs, ferro- (FO) and metamagnetic (MM), of [FeCp*][TCNQ] by analyzing their low-temperature structures using advanced diffraction techniques.
  • Both polymorphs consist of alternating chains of S = 1/2 [FeCp*]˙ cations and S = 1/2 [TCNQ]˙ anions, but they differ in the relative orientations of these chains, leading to distinct magnetic behaviors that do not interconvert thermally.
  • The study also identified a phase transition in the MM polymorph, with temperature and enthalpy determined through differential calorimetry; notably, the interchain Fe-Fe distances
View Article and Find Full Text PDF