Recycling Organoiridium Waste to [(1,5-Cyclooctadiene)IrCl].

We report the first process for iridium element recovery from organoiridium waste that is quantitative, pyrolysis-free, and generates no iridium metal. The key step is oxidative degradation of the waste by bleach to crude iridium(IV) hydroxide. Its treatment with hydrazine and then hydrogen peroxide gives synthetically important hexachloroiridic acid, which is converted to [(1,5-cyclooctadiene)IrCl] in 87% yield.

Pressurized Formic Acid Dehydrogenation: An Entropic Spring Replaces Hydrogen Compression Cost.

Formic acid is unique among liquid organic hydrogen carriers (LOHCs), because its dehydrogenation is highly entropically driven. This enables the evolution of high-pressure hydrogen at mild temperatures that is difficult to achieve with other LOHCs, conceptually by releasing the "spring" of energy stored entropically in the liquid carrier. Applications calling for hydrogen-on-demand, such as vehicle filling, require pressurized H.

Synthesis of 1,4-Diazacycles by Hydrogen Borrowing.

We report the syntheses of 1,4-diazacycles by diol-diamine coupling, uniquely made possible with a (pyridyl)phosphine-ligated ruthenium(II) catalyst (). The reactions can exploit either two sequential -alkylations or an intermediate tautomerization pathway to yield piperazines and diazepanes; diazepanes are generally inaccessible by catalytic routes. Our conditions tolerate different amines and alcohols that are relevant to key medicinal platforms.

Heterobimetallic complexes of IrM (M = Fe, Co, and Ni) core and bridging 2-(diphenylphosphino)pyridine: electronic structure and electrochemical behavior.

Three complexes based on an Ir-M (M = Fe, Co, and Ni) heterobimetallic core and 2-(diphenylphosphino)pyridine (PhPPy) ligand were synthesized via the reaction of trans-[IrCl(CO)(PhPPy)] and the corresponding metal chloride. Their structures were established by single-crystal X-ray diffraction as [Ir(CO)(μ-Cl)(μ-PhPPy)FeCl]·2CHCl (2), [IrCl(CO)(μ-PhPPy)CoCl]·2CHCl (3), and [Ir(CO)(μ-Cl)(μ-PhPPy)NiCl]·2CHCl (4). Time-dependent DFT computations suggest a donor-acceptor interaction between a filled 5d orbital on iridium and an empty orbital on the first-row metal atom, which is supported by UV-vis studies.

Ruthenium Catalyzed Tandem Pictet-Spengler Reaction.

We report a pyridyl-phosphine ruthenium(II) catalyzed tandem alcohol amination/Pictet-Spengler reaction sequence to synthesize tetrahydro-β-carbolines from an alcohol and tryptamine. Our conditions use a Lewis acid cocatalyst, In(OTf), that is compatible with typically amination and an Pictet-Spengler cyclization. This method proceeds well with benzylic alcohols, heterocyclic carbinols, and aliphatic alcohols.

A New Mechanism of Metal-Ligand Cooperative Catalysis in Transfer Hydrogenation of Ketones.

We report iridium catalysts IrCl(η-Cp*)(κ-(2-pyridyl)CHNSOCHX) (, X = CH and , X = F) for transfer hydrogenation of ketones with 2-propanol that operate by a previously unseen metal-ligand cooperative mechanism. Under the reaction conditions, complexes ( and ) derivatize to a series of catalytic intermediates: Ir(η-Cp*)(κ-(CHN)CHNSOAr) (), IrH(ηCp*)(κ-(2-pyridyl)CHNSOAr) (), and Ir(η-Cp*)(κ-(2-pyridyl)CHNSOAr) (). The structures of and were established by single-crystal X-ray diffraction.

Upgrading Biodiesel from Vegetable Oils by Hydrogen Transfer to its Fatty Esters.

Conversion of vegetable-derived triglycerides to fatty acid methyl esters (FAMEs) is a popular approach to the generation of biodiesel fuels and the basis of a growing industry. Drawbacks of the strategy are that (a) the glycerol backbone of the triglyceride is discarded as waste, and (2) most available natural triglycerides in the U.S.

Iridium Catalysts for Acceptorless Dehydrogenation of Alcohols to Carboxylic Acids: Scope and Mechanism.

We introduce iridium-based conditions for the conversion of primary alcohols to potassium carboxylates (or carboxylic acids) in the presence of potassium hydroxide and either [Ir(2-PyCH(CHN))(COD)]OTf () or [Ir(2-PyCHPBu )(COD)]OTf (). The method provides both aliphatic and benzylic carboxylates in high yield and with outstanding functional group tolerance. We illustrate the application of this method to a diverse variety of primary alcohols, including those involving heterocycles and even free amines.

Iridium-based hydride transfer catalysts: from hydrogen storage to fine chemicals.

Selective hydrogen transfer remains a central research focus in catalysis: hydrogenation and dehydrogenation have central roles, both historical and contemporary, in all aspects of fuel, agricultural, pharmaceutical, and fine chemical synthesis. Our lab has been involved in this area by designing homogeneous catalysts for dehydrogenation and hydrogen transfer that fill needs ranging from on-demand hydrogen storage to fine chemical synthesis. A keen eye toward mechanism has enabled us to develop systems with excellent selectivity and longevity and demonstrate these in a diversity of high-value applications.

Favored use of immunoglobulin V(H)4 Genes in AIDS-associated B-cell lymphoma.

We examined the lg heavy chain variable region genes (Ig V(H) genes) expressed in biopsy specimens of 10 patients with acquired immunodeficiency syndrome (AIDS)-associated lymphoma. Eight expressed Ig V(H) genes of the V(H)4 group, indicating a bias toward expression of Ig V(H) genes of this subgroup. Sequence analyses of Ig V(H) genes isolated from any one lymphoma did not reveal evidence for intraclonal diversity.

Common clonal origin of chronic lymphocytic leukemia and high-grade lymphoma of Richter's syndrome.

Patients with B-cell chronic lymphocytic leukemia (CLL) infrequently may develop high-grade B-cell lymphoma, or Richter's syndrome lymphoma (RS lymphoma). Such lymphomas differ from the original leukemia in both histology and clinical behavior. Studies seeking to define the clonal relationship between the cells of the two malignancies in any one patient have yielded conflicting reports.

[Natural autoantibodies of neonatal rats detectable by a hybridoma technic].

Neonatal rat hybridomas were tested for natural autoantibodies (NAA) production, using different screening procedures. NAA were discovered in 35% of immunoglobulins producing hybridomas. Radioimmunoassay (RIA) on brain and liver homogenates and immunocytochemistry on brain sections are the procedures of choice revealing the major part of the identified NAA.

Allelic exclusion frequency analysis and molecular characteristics of immunoglobulins secreted by the hybridomas expressing both allelic genes.

The investigation of 750 B-lymphocyte hybridoma clones obtained by fusion of mouse myeloma and newborn heterozygous Igk-1a/Igk-1b rat splenocytes has revealed that 9.8% of Ig kappa-chain loci are rearranged productively. Seventeen hybridomas secrete kappa-chains of both allelic variants.

Monoclonal antibodies to dog heart sarcoplasmic reticulum. Antibodies that inhibit Ca2+-pump systems of cardiac and skeletal muscles.

Purified sarcoplasmic reticulum (SR) vesicles from dog heart were used as an antigen to produce monoclonal antibodies (mAbs) to the Ca2+-ATPase. Nine of twelve clones of hybridoma cells produce mAbs which cross-react with seven SR preparation isolated from cardiac and skeletal muscles of various species. Three mAbs of IgM type interact with the 45-kDa tryptic fragment of rabbit skeletal muscle Ca2+-ATPase and markedly inhibit Ca2+ uptake (by 95%) and ATPase activity (by 80%) and decrease (by 30-50%) the steady-state level of the Ca2+-ATPase phosphoenzyme.

[Allelic exclusion in hybridomas. II. Characteristics of the synthesis of 2 allelic variants of rat immunoglobulin kappa-chains in a cloned hybridoma line].

Production of Igk-1a and Igk-1b allelic variants of rat Ig kappa-chains in hybridoma clone 4C2 was studied. Gel-filtration of the culture fluid demonstrates that the cells secrete isolated L-chains in monomeric and dimeric form. Different L-chain allotypes fail to associate in dimers.

Monoclonal antibodies to dog heart sarcoplasmic reticulum. Application of the mAbs for studies of the structure and function of Ca2+-pumps.

One of monoclonal antibodies (mAbs) raised against purified dog heart sarcoplasmic reticulum (SR) efficiently decreases Ca2+-pump and Ca2+-ATPase activities of various SR preparations. The ATPase activity that is insensitive to the mAb (10-20% of the initial value) is present both in light and heavy fractions of rabbit skeletal muscle SR. The residual activity is completely blocked by 2 microM vanadate.

[Analysis of the frequency of allelic exclusion of immunoglobulin light chain genes and molecular characteristics of immunoglobulins secreted by hybridomas with expression of both allelic genes].

The investigation of 750 B-lymphocyte hybridoma clones obtained by fusion of mouse myeloma and newborn heterozygous Igk-la/Igk-1b rat splenocytes has revealed that 9,8% of Ig kappa-chain genes are rearranged productively. Seventeen hybridomas secrete kappa-chains of both allelic variants. The analysis of IgM molecules of nine such clones demonstrated that in six cases only one L-chain allotype is present in IgM.

[Use of monoclonal antibodies against the light-chain immunoglobulins of the rat in the radioimmune analysis of differentiated lymphocyte antigens of the mouse].

Spleen cells from SJL mice immunized with rat immunoglobulin light chains were fused with X-63 myeloma. Seven hybridoma lines were obtained. Monoclonal antibodies (McAB) secreted by lines L1G9, L2B2 and L3E8 were purified and labeled by 125I.

[Allelic exclusion in hybridomas. I. Isolation and properties of a hybrid clone producing two allelic variants of light chain immunoglobulins in the rat].

Expression of RI-1a and RI-1b allelic genes controlling the production of rat lg kappa L-chains by hybridoma cells in vitro was studied. By fusing mouse myeloma cells with RI-1a/RI-1b heterozygous rat splenocytes the unique cloned hybrid cell line secreting both allelic variants has been established. This line may have appeared because cell hybridization made it possible to fix the rare case of correct rearrangement of the kappa chain gene segments on both homologous chromosomes.