Catalysis-chemistry

Ongoma, Peter O. published the artcileMechanistic elucidation of linker and ancillary ligand substitution reactions in Pt(II) dinuclear complexes, SDS of cas: 6972-05-0, the publication is Dalton Transactions (2013), 42(8), 2724-2734, database is CAplus and MEDLINE.

The rate of substitution of aqua ligands by three nucleophiles, thiourea (TU), N,N-dimethylthiourea (DMTU) and N,N,N,N-tetramethylthiourea (TMTU), for [cis-{PtOH₂(NH₃)₂}₂-¦Ì-pyrazine](ClO₄)₂ (pzn), [cis-{PtOH₂(NH₃)₂}₂-¦Ì-2,3-dimethylpyrazine](ClO₄)₂ (2,3pzn), [cis-{PtOH₂(NH₃)₂}₂-¦Ì-2,5-pyrazine](ClO₄)₂ (2,5pzn) and [cis-{PtOH₂(NH₃)₂}₂-¦Ì-2,6-dimethylpyrazine](ClO₄)₂ (2,6pzn) was studied under pseudo 1st-order conditions as a function of concentration and temperature by stopped-flow and UV-Visible spectrophotometry. The reaction proceeded in three consecutive steps; each step follows 1st order kinetics with respect to each complex and nucleophile. The pseudo 1st-order rate constants, k_obs(1/2/3), for sequential substitution of the aqua ligands and subsequent displacement of the linker obeyed the rate law: k_obs(1/2/3) = k_(1/2/3)[nucleophile]. The steric hindrance properties of the pyrazine-bridging ligand control the overall reaction pattern. The order of reactivity of the complexes is 2,3pzn ¡Ö 2,5pzn < 2,6pzn < pzn. The difference in reactivity attributed to the steric crowding at the Pt(II) center imposed by the Me groups reduces the lability of the aqua complexes. The order of reactivity of the nucleophiles decreases with the increase in steric demand TU > DMTU > TMTU. ¹H and ¹⁹⁵Pt NMR spectroscopic results confirmed the observed dissociation of the bridging ligand from the metal center of the cis-dinuclear complexes and its derivatives in the 3rd step. The dissociation process is accelerated by the introduction of the steric effect on the linker in conjunction with the increased ligand field strength imparted by addnl. thiourea ligands at each metal center. The large neg. entropy of activation ¦¤S^¡Ù values in all cases support an associative substitution mechanism.

Dalton Transactions published new progress about 6972-05-0. 6972-05-0 belongs to catalysis-chemistry, auxiliary class Thiourea,Amine,Aliphatic hydrocarbon chain,Amide, name is 1,1-Dimethylthiourea, and the molecular formula is C3H8N2S, SDS of cas: 6972-05-0.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Ongoma, Peter published the artcileThe ¦Ð-acceptor effect in the substitution reactions of tridentate N-donor ligand complexes of platinum(ii): a detailed kinetic and mechanistic study, Formula: C3H8N2S, the publication is Dalton Transactions (2012), 41(35), 10724-10730, database is CAplus and MEDLINE.

The nucleophilic substitution reactions of complexes [Pt{4′-(2”’-CH₃-phenyl)-2,2′:6′,2”-terpyridine}Cl]CF₃SO₃, [CH₃PhPtCl], [Pt{4′-(2”’-CH₃-phenyl)-6-(3”-isoquinoyl)-2,2’bipyridine}Cl]SbF₆, [CH₃PhisoqPtCl], [Pt{2-(2′-pyridyl)-1,10-phenanthroline}Cl]Cl, [pyPhenPtCl], and [Pt(terpyridine)Cl]⁺, [PtCl] with a series of nucleophiles: thiourea (TU), N,N-dimethylthiourea (DMTU), N,N,N,N-tetramethylthiourea (TMTU), I^–, Br^–, and SCN^– were studied in 0.1 M LiCF₃SO₃ in methanol (in the presence of 10 mM LiCl). The reactivity of the investigated complexes follows the order pyPhenPtCl > PtCl > CH₃PhPtCl > CH₃PhisoqPtCl. The lability of the chloride ligand is dependent on the strength of ¦Ð-backbonding properties of the spectator ligands around the platinum center. The exptl. data is strongly supported by DFT calculations The dependence of the second-order rate constants on concentration of the nucleophiles as well as the large neg. values reported for the activation entropy (¦¤S^?) confirmed an associative mechanism of substitution.

Dalton Transactions published new progress about 6972-05-0. 6972-05-0 belongs to catalysis-chemistry, auxiliary class Thiourea,Amine,Aliphatic hydrocarbon chain,Amide, name is 1,1-Dimethylthiourea, and the molecular formula is C3H8N2S, Formula: C3H8N2S.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Kinunda, Grace published the artcileUnderstanding the electronic and ¦Ð-conjugation roles of quinoline on ligand substitution reactions of platinum(II) complexes, Recommanded Product: 1,1-Dimethylthiourea, the publication is Transition Metal Chemistry (Dordrecht, Netherlands) (2014), 39(4), 451-459, database is CAplus.

A kinetic and mechanistic study of chloride substitution by thiourea nucleophiles, thiourea, N-methylthiourea, N,N-dimethylthiourea and N,N,N’,N’-tetramethylthiourea in the complexes chlorobis-(2-pyridylmethyl)amineplatinum(II) (Pt1), chloro N-(2-pyridinylmethyl)-8-quinolinamineplatinum(II) (Pt2), chloro N-(2-pyridinylmethylene)-8-quinolinamineplatinum(II) (Pt3) and chlorobis(8-quinolinyl)amineplatinum(II) (Pt4) was undertaken under pseudo-first-order conditions using UV-visible spectrophotometry. Lability of the chloro leaving group is dependent on the strength of ¦Ð-interactions between the filled d¦Ð-orbitals of the metal and the empty ¦Ð^*-orbitals of the chelating ligand in the following manner: Pt1 > Pt3 > Pt2 > Pt4. Introduction of the quinoline moiety within the nonlabile chelated framework of the Pt(II) complexes results in a more electron-rich metal center which retards the approach of the nucleophile through repulsion. Also, the net ¦Ò-effect of the ligand moiety plays a significant role in controlling the reactivity of the complexes. The exptl. results are interpreted with the aid of computational data obtained by d. functional theory (B3LYP(CPCM)/LANL2DZp//B3LYP/-LANL2DZp) calculations The mode of substitution remains associative as supported by neg. entropies and the dependence of the 2nd-order rate constants on the concentration of entering nucleophiles.

Transition Metal Chemistry (Dordrecht, Netherlands) published new progress about 6972-05-0. 6972-05-0 belongs to catalysis-chemistry, auxiliary class Thiourea,Amine,Aliphatic hydrocarbon chain,Amide, name is 1,1-Dimethylthiourea, and the molecular formula is C3H8N2S, Recommanded Product: 1,1-Dimethylthiourea.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Valandro, Silvano R. published the artcileAggregation-Enhanced Two-Photon Absorption of Anionic Conjugated Polyelectrolytes, Product Details of C3H12Cl2N2, the publication is Journal of Physical Chemistry Letters (2020), 11(19), 8292-8296, database is CAplus and MEDLINE.

The two-photon absorption properties of anionic poly(phenylene ethynylene)-type conjugated oligo- and polyelectrolytes are studied in molecularly dissolved and aggregated forms in aqueous solution Several different polyvalent cations are used to induce aggregation. It is found that both materials in the aggregated form exhibit enhanced two-photon excited fluorescence (2PEF) and two-photon cross section (¦Ò₂) compared with the molecularly dissolved structures. The 2PEF and ¦Ò₂ are unaffected by the nature of the polyvalent cation that is used to induce aggregation. The two-photon absorption cross section enhancement arises because of the increase in the difference dipole moment (¦¤¦Ì) in the aggregates of the conjugated materials, an effect that is attributed to the introduction of charge transfer character into the aggregate excited state.

Journal of Physical Chemistry Letters published new progress about 10517-44-9. 10517-44-9 belongs to catalysis-chemistry, auxiliary class Salt,Amine,Aliphatic hydrocarbon chain, name is Propane-1,3-diamine dihydrochloride, and the molecular formula is C12H15ClO3, Product Details of C3H12Cl2N2.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Tan, Kathrin published the artcileHeteroaromatic Inhibitors of the Astacin Proteinases Meprin ¦Á, Meprin ¦Â and Ovastacin Discovered by a Scaffold-Hopping Approach, Recommanded Product: 3-Benzoylpropionicacid, the publication is ChemMedChem (2021), 16(6), 976-988, database is CAplus and MEDLINE.

Astacin metalloproteinases, in particular meprins ¦Á and ¦Â, as well as ovastacin, are emerging drug targets. Drug-discovery efforts have led to the development of the first potent and selective inhibitors in the last few years. However, the most recent compounds are based on a highly flexible tertiary amine scaffold that could cause metabolic liabilities or decreased potency due to the entropic penalty upon binding to the target. Thus, the aim of this study was to discover novel conformationally constrained scaffolds as starting points for further inhibitor optimization. Shifting from flexible tertiary amines to rigid heteroaromatic cores resulted in a boost in inhibitory activity. Moreover, some compounds already exhibited higher activity against individual astacin proteinases compared to recently reported inhibitors and also a favorable off-target selectivity profile, thus qualifying them as very suitable chem. probes for target validation.

ChemMedChem published new progress about 2051-95-8. 2051-95-8 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ketone, name is 3-Benzoylpropionicacid, and the molecular formula is C5H5N3S, Recommanded Product: 3-Benzoylpropionicacid.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Sachin, Kalme published the artcileF-18 Labeling Protocol of Peptides Based on Chemically Orthogonal Strain-Promoted Cycloaddition under Physiologically Friendly Reaction Conditions, Quality Control of 17351-62-1, the publication is Bioconjugate Chemistry (2012), 23(8), 1680-1686, database is CAplus and MEDLINE.

We introduce the high-throughput synthesis of various ¹⁸F-labeled peptide tracers by a straightforward ¹⁸F-labeling protocol based on a chemo-orthogonal strain-promoted alkyne azide cycloaddition (SPAAC) using aza-dibenzocyclootyne-substituted peptides as precursors with ¹⁸F-azide synthon to develop peptide based positron emission tomog. (PET) mol. imaging probes. The SPAAC reaction and subsequent chemo-orthogonal purification reaction with azide resin proceeded quickly and selectively under physiol. friendly reaction conditions (i.e., toxic chem. reagents-free, aqueous medium, room temperature, and pH ¡Ö7), and provided four ¹⁸F-labeled tumor targetable bioactive peptides such as cyclic Arg-Gly-Asp (cRGD) peptide, bombesin (BBN), c-Met binding peptide (cMBP), and apoptosis targeting peptide (ApoPep) in high radiochem. yields as direct injectable solutions without any HPLC purification and/or formulation processes. In vitro binding assay and in vivo PET mol. imaging study using the ¹⁸F-labeled cRGD peptide also demonstrated a successful application of our ¹⁸F-labeling protocol.

Bioconjugate Chemistry published new progress about 17351-62-1. 17351-62-1 belongs to catalysis-chemistry, auxiliary class Salt,Amine, name is Tetrabutylammonium hydrogencarbonate, and the molecular formula is C17H37NO3, Quality Control of 17351-62-1.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Buu-Hoi, N. P. published the artcileChemistry of carbazoles. IV. Synthesis and rearrangement of benzo- and dibenzocarbazolenines, Synthetic Route of 1949-41-3, the publication is Bulletin de la Societe Chimique de France (1970), 628-31, database is CAplus and MEDLINE.

2-Methyl-1-tetralone ¦Á-naphthylhydrazone was cyclized by heating with HCl-saturated AcOH to give 6a-methyl-5,6-dihydrodibenzo[a,i]carbazole (I). Similarly were prepared 13a-methyl-5,6-dihydrodibenzo[a,g]carbazole (II) and 6a-methyl-5,6-dihydrobenzo[a]carbazole (III). The dehydrogenation of I-III over Pd/C gave 13H-dibenzo-[a,i]carba zole, 7H-dibenzo[a,g]carbazole and 11H-benzo[a]-carbazole, resp.

Bulletin de la Societe Chimique de France published new progress about 1949-41-3. 1949-41-3 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene, name is 2-Methyl-4-phenylbutanoic acid, and the molecular formula is C11H14O2, Synthetic Route of 1949-41-3.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Claes, Pieter published the artcilePalladium(II)-Catalyzed Synthesis of 2H,3’H-Spiro[benzofuran-3,2′-naphthoquinones], Quality Control of 1798-04-5, the publication is Journal of Organic Chemistry (2013), 78(17), 8330-8339, database is CAplus and MEDLINE.

2H,3’H-Spiro[benzofuran-3,2′-naphthoquinones], constituting a new spiroheterocyclic skeleton, were synthesized starting from 2-aryloxymethyl-1,4-naphthoquinones by means of a palladium(II)-catalyzed reaction, which is a new spirocyclic transformation. Under optimal conditions, i.e. 10 mol % of palladium(II) acetate, 15 mol % of 3,5-dichloropyridine, and 5 mol % of trifluoroacetic acid in acetic acid at 110 ¡ãC, various 2H,3’H-spiro[benzofuran-3,2′-naphthoquinones] were synthesized in yields strongly dependent on the substitution pattern of the aryloxy group. Unsubstituted or ortho-substituted 2-aryloxymethyl-1,4-quinones were found to rearrange toward the corresponding 2-(4-hydroxyaryl)-1,4-quinones upon treatment with trifluoroacetic acid.

Journal of Organic Chemistry published new progress about 1798-04-5. 1798-04-5 belongs to catalysis-chemistry, auxiliary class Carboxylic acid,Benzene,Ether, name is 2-(4-(tert-Butyl)phenoxy)acetic acid, and the molecular formula is C12H16O3, Quality Control of 1798-04-5.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Eggleston, Drake S. published the artcileTetrasubstituted [14]-1,3,8,10-tetraeneN₄ macrocyclic complexes: synthesis, organic precursor, and template reaction mechanism, Computed Properties of 10517-44-9, the publication is Inorganic Chemistry (1980), 19(6), 1593-9, database is CAplus.

Template syntheses have been studied for macrocyclic complexes derived from 1,3-diaminopropane (DAP), 1-phenyl-1,2-propanedione (AB), and metal(II) acetate, where the metal is Fe, Co or Ni. The products were characterized by elemental analyses and conductivity and spectroscopic methods (IR, UV-visible, and ¹H and ¹³C NMR). The ¹³C NMR anal. indicated that the template synthesis is regiospecific, producing only one of the two possible isomeric products corresponding to the ligand 2,9-dimethyl-3,10-diphenyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene, trans-MePhTIM. X-ray diffraction data for a crystal of [Co(MePhTIM)Cl₂]PF₆ are also consistent with a centrosym. trans isomer product. ¹H NMR studies of the 1:1 condensation of AB and DAP in the absence of metals indicates a mixture of products from which the major product was isolated and found to be 2-benzoyl-2-methylhexahydropyrimidine. Reaction of this compound with metal salts yields the isomerically pure trans-MePhTIM complexes. The synthetic results and ¹H NMR studies are consistent with a proposed template mechanism in which AB and DAP react first to form 2-benzoyl-2-methylhexahydropyrimidine in equilibrium with its open-chain Schiff-base tautomer. Subsequent condensation of two of the Schiff-base mols. under the influence of a metal ion leads exclusively to the trans-MePhTIM complex. Results of other experiments and syntheses using an unsym. substituted alkyl ¦Á-diketone indicate that the mechanism is also applicable to related systems.

Inorganic Chemistry published new progress about 10517-44-9. 10517-44-9 belongs to catalysis-chemistry, auxiliary class Salt,Amine,Aliphatic hydrocarbon chain, name is Propane-1,3-diamine dihydrochloride, and the molecular formula is C3H12Cl2N2, Computed Properties of 10517-44-9.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia

Jodeh, Shehdeh published the artcileExperimental and theoretical study for removal of trimethoprim from wastewater using organically modified silica with pyrazole-3-carbaldehyde bridged to copper ions, Quality Control of 13822-56-5, the publication is BMC Chemistry (2022), 16(1), 17, database is CAplus and MEDLINE.

SiNP-Cu, a chelating matrix, was produced by delaying and slowing 1.5-dimethyl-1H-pyrazole-3-carbaldehyde on silica gel from functionalized with 3-aminopropyltrimethoxysilane. The prepared sorbent material was characterized using several techniques including BET surface area, FT-IR spectroscopy, SEM (SEM), thermogravimetric anal. (TGA), and nitrogen adsorption-desorption isotherm. The pseudo-second-order model provided the best correlation due to the big match between the exptl. and theor. of different adsorption coefficients The Langmuir and Freundlich adsorption models were used and the study showed a better match with the Freundlich model with a capacity of removal reached up to 420 mg g^-1. The removal capacity was dependent on pH and increased by increasing pH. The removal percentage reached 91;5% at pH = 8. The adsorbent demonstrated a high percentage removal of TMP, reaching more than 94% when increased pH. The sample was simply regenerated by soaking it for a few minutes in 1 N HCl and drying it. The sorbent was repeated five times with no discernible decrease in removal capacity. The thermodn. study also showed endothermic, increasing randomness and not spontaneous. The free energy was 2.71 kJ/mol at 320 K. The findings of the DFT B3LYP/6-31 + g (d, p) local reactivity descriptors revealed that nitrogen atoms and ¦Ð-electrons of the benzene and pyrimidine rings in the TMP are responsible for the adsorption process with the SiNP surface. The neg. values of the adsorption energies obtained by mol. dynamic simulation indicated the spontaneity of the adsorption process. The global reactivity indexes prove that TMP is stable and it can be removed from wastewater using SiNP surface. The results of the local reactivity indexes concluded that the active centers for the adsorption process are the nitrogen atoms and the ¦Ð-electrons of the pyrimidine and benzene rings. Furthermore, the pos. value of the maximum charge transfer number (¦¤N) proves that TMP has a great tendency to donate electrons to SiNP surface during the process of adsorption.

BMC Chemistry published new progress about 13822-56-5. 13822-56-5 belongs to catalysis-chemistry, auxiliary class Organic Silicones, name is 3-(Trimethoxysilyl)propan-1-amine, and the molecular formula is C6H17NO3Si, Quality Control of 13822-56-5.

Referemce:
https://courses.lumenlearning.com/boundless-chemistry/chapter/catalysis/,
Catalysis – Wikipedia