Synthesis, Structure, and Olefin Polymerization Behavior of Constrained-Geometry Group 4 Metallacarboranes Incorporating Imido-Dicarbollyl Ligands
摘要:
New imido-carboranes 1-(CH=NC6H3R2-2,6)-1,2-C2B10H11 (R = Pr-i (3a), Me (3b)) were successfully prepared by Schiff base condensation of 1-CHO-1,2-C2B10H11 with R2C6H3NH2. They were readily converted into the corresponding imido-dicarbollyl ligands 7-(CH=NHC6H3R2-2,6)-7,8-C2B9H11 (R = Pr-i (4a), Me (4b)) by refluxing in dry MeOH. Treatment of 3a with Ti(NMe2)(4) in hot toluene gave a constrained-geometry complex, [eta(1):eta(5)-((Pr2C6H3N)-Pr-i=CH)C2B9H10]Ti(NMe2)(2) (5a). Under the same reaction conditions, interaction of 3b with Ti(NMe2)(4) produced a mixture of [eta(1):eta(5)-(Me2C6H3N=CH)C2B9H10]Ti(NMe2)(2) (5b) and [eta(1):eta(5)-(Me2N)CH(NMe2)(C2B9H10)Ti(NMe2)(2) (8). Reaction of 4a with M(NMe2)(4) in toluene/DME at room temperature afforded 5a and [eta(1):eta(5)-((Pr2C6H3N)-Pr-i=CH)C2B9H10]M(NMe2)(2)(NHMe2) (M = Zr (6a), Hf (7a)), respectively. Complexes 5a, 6a, and 7a were active catalysts for the polymerization of ethylene in the presence of MMAO with activities of 3-16 kg/mol.h.atm. These new complexes were fully characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 3a, 3b, 4a, 5a, 5b, 6a, 7a, and 8 were further confirmed by single-crystal X-ray analyses.
Selective Catalytic B–H Arylation of <i>o</i>-Carboranyl Aldehydes by a Transient Directing Strategy
作者:Xiaolei Zhang、Hongning Zheng、Jie Li、Fei Xu、Jing Zhao、Hong Yan
DOI:10.1021/jacs.7b07160
日期:2017.10.18
Carboranyl aldehydes are among the most useful synthons in derivatization of carboranes. However, compared to the utilization of carboranyl carboxylic acids in selective B-H bond functionalizations, the synthetic application of carboranyl aldehydes is limited due to the weakly coordinating nature of the aldehyde group. Herein, the direct arylation of o-carboranyl aldehydes has been developed via Pd-catalyzed
Iron(III)-catalyzed aerobic oxidation for the synthesis of 1-benzoxazolyl-o-carboranes
作者:Ji Wu、Ke Cao、Cai-Yan Zhang、Xin-Yu Wen、Bo Li、Junxiao Yang
DOI:10.1016/j.jorganchem.2021.121881
日期:2021.7
A FeCl3 catalyzed tandem condensation/cyclization/aerobicoxidation process for synthesis of 1-benzoxazolyl-o-carboranes has been developed. The degradation of o-carborane in the presence of aza-/oxa-nucleophiles was completely suppressed, and a series of 1-benzoxazolyl-o-carboranes, 1-benzothiazolyl-o-carborane and 1-benzimidazolyl-o-carborane have been synthesized with good to excellent yields. This
One-pot synthesis of an indole-substituted 7,8-dicarba-nido-dodecahydroundecaborate(−1)
作者:W. Neumann、R. Frank、E. Hey-Hawkins
DOI:10.1039/c4dt03218g
日期:——
Carbaboranes are increasingly used as pharmacophores to replace phenyl substituents in established drug molecules. In contrast to traditional organic chemistry, elaborate procedures to introduce functionality frequently fail in the case of carbaboranes and their chemistry is often hampered by degradation of the cluster. Herein, the development of a one-pot synthesis of a water-soluble N-nido-dicarbaborato
Synthesis of Functionalized Carboranes as Potential Anticancer and BNCT Agents
作者:Venkata Jaganmohan Reddy、Matthew M. Roforth、Chalet Tan、M. Venkat Ram Reddy
DOI:10.1021/ic061948i
日期:2007.1.1
aldehydes react with alpha,beta-unsaturated esters, ketones, and nitriles in the presence of DABCO to provide functionalized carboranyl alcohols in good yields. Acetates of these alcohols undergo a facile isomerization with a variety of nucleophiles and afford structurally interesting carboranes. Biological evaluation of these molecules exhibited impressive antiproliferative activity for brain and breast