98-80-6Relevant articles and documents
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Gilman,Moore
, p. 3609 (1958)
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Novel biscapped and monocapped tris(dioxime) Mn(II) complexes: X-ray crystal structure of the first cationic tris(dioxime) Mn(II) complex [Mn(CDOH)3BPh]OH (CDOH2 = 1,2-cyclohexanedione dioxime)
Hsieh, Wen-Yuan,Liu, Shuang
, p. 5034 - 5043 (2006)
This report describes the synthesis and characterization of a series of novel biscapped and monocapped tris-(dioxime) Mn(II) complexes [Mn(dioxime) 3(BR)2] and [Mn(dioxime)3BR]+ (dioxime = cyclohexanedione dioxime (CDOH2) and 1,2-dimethylglyoxyl dioxime (DMGH2); R = Me, n-Bu, and Ph). All tris(dioxime) Mn(II) complexes have been characterized by elemental analysis, IR, UV/vis, cyclic voltammetry, ESI-MS, and, in the cases of [Mn(CDOH)3BPh] OH·CHCl3 and [Mn(CDO)(CDOH)2(BBu(OC 2H5))2], X-ray crystallography. It was found that biscapped Mn(II) complexes [Mn(dioxime)3(BR)2] are not stable in the presence of water and readily hydrolyze to form monocapped cationic complexes [M(dioxime)3BR]+. This instability is most likely caused by mismatch between the size of Mn(II) and the coordination cavity of the biscapped tris(dioxime) ligands. In contrast, monocapped cationic complexes [M(dioxime)3BR]+ are very stable in aqueous solution even in the presence of PDTA (1,2-diaminopropane-N,N,N′,N′- tetraacetic acid) because of the kinetic inertness imposed by the monocapped tris(dioxime) chelators that are able to completely wrap Mn(II) into their N6 coordination cavity. [Mn(CDO)3BPh]OH has a distorted trigonal prismatic coordination geometry, with the Mn(II) being bonded by six imine-N donors. The hydroxyl groups from three dioxime chelating arms form very strong intramolecular hydrogen bonds with the hydroxide counterion so that the structure of [Mn(CDOH)3BPh]OH can be considered as being the clathrochelate with the hydroxide counterion as a cap .
Fourth subgroup metal complex with rigid annular bridging structure and application of fourth subgroup metal complex
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Paragraph 0058; 0061-0062, (2021/06/23)
The invention belongs to the technical field of olefin polymerization catalysts, and particularly relates to a fourth subgroup metal complex with a rigid annular bridging structure and an application of the fourth subgroup metal complex. The fourth subgroup metal complex provided by the invention has a structure represented by a formula (A) or a formula (B), X is halogen or alkyl; and M is titanium, zirconium or hafnium. On the basis of a non-metallocene catalyst, a bridging structure in catalyst molecules is improved and upgraded, and a brand-new metal complex with excellent catalytic performance and good high-temperature tolerance is designed; when the fourth subgroup metal complex is used as a main catalyst to catalyze olefin polymerization reaction, under the activation action of a small amount of mixed cocatalyst, the fourth subgroup metal complex can efficiently catalyze the copolymerization reaction of ethylene and alpha-olefin to obtain polyolefin with high molecular weight and high comonomer insertion rate.
Pd- And Ni-Based Systems for the Catalytic Borylation of Aryl (Pseudo)halides with B2(OH)4
Munteanu, Charissa,Spiller, Taylor E.,Qiu, Jun,Delmonte, Albert J.,Wisniewski, Steven R.,Simmons, Eric M.,Frantz, Doug E.
, p. 10334 - 10349 (2020/09/18)
Despite recent advancements in metal-catalyzed borylations of aryl (pseudo)halides, there is a continuing need to develop robust methods to access both early-stage and late-stage organoboron intermediates amendable for further functionalization. In particular, the development of general catalytic systems that operate under mild reaction conditions across a broad range of electrophilic partners remains elusive. Herein, we report the development and application of three catalytic systems (two Pd-based and one Ni-based) for the direct borylation of aryl (pseudo)halides using tetrahydroxydiboron (B2(OH)4). For the Pd-based catalyst systems, we have identified general reaction conditions that allow for the sequestration of halide ions through simple precipitation that results in catalyst loadings as low as 0.01 mol % (100 ppm) and reaction temperatures as low as room temperature. We also describe a complementary Ni-based catalyst system that employs simple unligated Ni(II) salts as an inexpensive alternative to the Pd-based systems for the borylation of aryl (pseudo)halides. Extrapolation of all three systems to a one-pot tandem borylation/Suzuki-Miyaura cross-coupling is also demonstrated on advanced intermediates and drug substances.