10.1039/b904615a
The study focuses on the oxidation of Ni(II) N-confused porphyrins (NCPs) using azo radical initiators, which leads to an unexpected intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate. The main chemicals used in the study include Ni(II) NCPs, azo radical initiators such as AIBN (2,2'-azobisisobutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), and diethyl 2,2'-azobis(2-methylpropionate). These chemicals serve the purpose of oxidizing Ni(II) NCPs to Ni(III) NCPs, which are key intermediates in many chemical reactions and have biological significance in enzyme-catalyzed reactions. The study aims to understand the role of nickel in these enzymes and to model nickel biosites synthetically, which could help in investigating the precise function of the nickel ion in biological processes. The research also explores the stability and reactivity of Ni(III) NCPs, which are rare and usually unstable, and the results provide insights into the oxidative chemistry of Ni(II) porphyrins and the potential applications of Ni(III) NCPs in biomimetic nickel chemistry.
10.1007/s00706-013-0925-7
This research presents the development of a heterogeneous palladium catalyst supported by a polymerized functional ionic liquid for the reductive homocoupling of aryl halides. The purpose of the study was to create a recyclable catalyst that could selectively catalyze the formation of biaryls, which are important building blocks in pharmaceuticals and agrochemicals, under mild conditions. The researchers synthesized a homopolymer of 3-(cyanomethyl)-1-vinylimidazolium hexafluorophosphate and used it to support Pd nanoparticles, resulting in the Pd@poly-CN-PF6 catalyst. This catalyst was found to efficiently catalyze the homocoupling reactions of aryl halides in water at 100°C with good yields. The catalyst could be recycled and reused multiple times with only a slight loss in activity, which was attributed to palladium leaching at high temperature and aggregation of palladium nanoparticles. Key chemicals used in the process included 1-vinylimidazole, 2-chloroacetonitrile, potassium hexafluorophosphate, azodiisobutyronitrile (AIBN), and sodium borohydride (NaBH4) for the synthesis of the polymer and the Pd nanoparticles, as well as aryl halides, NaOH, and ascorbic acid in the catalytic reactions.
10.1055/s-1985-31107
The research focuses on the development of a highly efficient synthesis method for 1-amino-2-chloroethanephosphonates, which are compounds of interest in the design of new antimetabolites. The study aimed to overcome the scarcity of known synthetic methods for these specific compounds, leveraging the availability of 2,2,2-trichloro precursors and the use of tri-n-butyltin hydride for the reduction of alkyl halides. The researchers successfully developed a method to prepare alkyl 1-amino-2-chloro- and 2,2-dichloroethanephosphonates in high yields through selective hydrogenolysis of the trichloroethyl compounds. Key chemicals used in the process include 1,2,2,2-tetrachloro-N-acylethylamines, trialkyl phosphites, tri-n-butyltin hydride, and azobisisobutyronitrile (AIBN) as a catalyst. The conclusions of the research highlight the simplicity and practicality of the method, which offers a significant advancement in the synthesis of these potentially bioactive compounds.
10.1016/0022-328X(93)83012-K
The study presented in the "Journal of Organometallic Chemistry" focuses on the synthesis, properties, and structural analysis of N,N-functionalized bis(amino)carbene molybdenum(0) carbonyl complexes. The researchers prepared the complexes by treating 1,2-bis(y-diphenylphosphinopropylaminojethane) with specific reagents, yielding electron-rich enetetramine ligands. These ligands were then used to form carbenemolybdenum title compounds, which were characterized by various spectroscopic techniques and X-ray crystallography. The study revealed that one of the compounds exhibited a rare example of a metal complex with both carbene- and n*-alkene-ligation. Additionally, the researchers investigated the reactivity of the complexes, including their reactions with 13CO, PEt3, and under thermal conditions, providing insights into the potential of these complexes in catalytic alkene metathesis reactions.
10.1039/b904615a
The research discusses the oxidation of Ni(II) N-confused porphyrins (NCPs) using azo radical initiators, leading to an intramolecular nucleophilic substitution reaction via a proposed Ni(III) NCP intermediate. The study aimed to understand the role of nickel in biological processes and enzyme-catalyzed reactions, particularly focusing on the stability and formation of Ni(III) species. The experiments involved treating Ni(II) NCPs with azo radical initiators such as AIBN, dimethyl 2,20-azobis(2-methylpropionate), and diethyl 2,20-azobis(2-methylpropionate) under optimized conditions (4 equivalents of AIBN and a reaction temperature of 60°C). The reaction yielded inner-substituted Ni(II) NCPs, with the involvement of Ni(III) intermediates proposed based on the observed products and inhibited reactions with the addition of electron scavengers or free radical inhibitors. Analyses used to characterize the products and intermediates included UV/Vis spectroscopy, 1H NMR, mass spectrometry, and high-resolution mass spectroscopy (HRMS), with the latter confirming the presence of the proposed Ni(III) intermediate. The study also reported the successful demetallation of the synthesized Ni(II) NCPs using concentrated hydrochloric acid, leading to free base inner-substituted NCPs, with the structure of one such compound confirmed by single crystal X-ray diffraction analysis.
10.1016/j.tet.2007.03.017
The research explores a novel method for radical cyclizations of hydrazones using a silicon-tethered 1-bromovinyl group as a radical precursor. The purpose is to develop an effective strategy for synthesizing chiral a-branched amines through intramolecular radical additions, expanding the versatility of silicon-tethered radical cyclizations. Tributyltin hydride (Bu?SnH) is a powerful reducing agent commonly used in organic synthesis to generate radicals. In this study, Bu?SnH serves as the radical initiator, providing the necessary hydrogen radical to initiate the radical cyclization process. Azobisisobutyronitrile (AIBN) is a widely used radical initiator in organic chemistry. It decomposes thermally to produce nitrogen gas and a pair of isobutyronitrile radicals. In this research, AIBN is used in conjunction with Bu?SnH to facilitate the generation of radicals. The study concludes that the silicon-tethered 1-bromovinyl group significantly enhances reactivity, allowing for efficient cyclizations with moderate to good yields. However, the 6-exo cyclizations were found to be non-selective and limited in scope due to issues with β-elimination. The research demonstrates a rational approach to enhancing reactivity in silicon-tethered cyclizations and highlights the potential for further developments in this area.
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