{"title":"Alkylzinc complexes derived from formylfluorenimide ligands: Synthesis, characterization and catalysis for hydroboration of aldehydes and ketones","authors":"Biao Wei, Zhibiao Qin, Hui Miao, Chaoqun Wang, Mengna Huang, Chengxu Liu, Cui-Bing Bai, Zheng Chen","doi":"10.1039/d4dt03395g","DOIUrl":null,"url":null,"abstract":"Five new alkyl zinc complexes supported by different formylfluorenimide ligands were prepared and characterized. Complex 1 was obtained by the reaction of 9-[N(CH3)2-Cy-N=CH]Fl (Cy = 2-cyclohexyl) (Fl = Fluorenyl) (L1) with diethylzinc (ZnEt2) in tetrahydrofuran. By reacting 9-[2-pyridyl-CH-N=CH]Fl (L2) with ZnEt2 in tetrahydrofuran to yield complex 2. Under analogous conditions, complexes 3 and 4 were obtained through the reaction of 9-[2-pyridyl-CH(CH3)-N=CH]Fl (L3) and 9-[8-quinoline-CH-N=CH]Fl(L4) with ZnEt2 in tetrahydrofuran, respectively. The above ligands formed a tridentate four-coordinate structure by introduction of THF molecule along with the elimination of one ethyl group during its coordination with zinc. Notably, the formylfluorenimide ligand 9-[2-phenoxy-Ph-N=CH]Fl(Ph = phenyl) (L5) bearing a phenoxy group exhibited unique reactivity compared to the other ligands, which formed a bidentate three-coordinated structure when reacting with ZnEt2 in THF. All complexes were characterized via 1H NMR, 13C NMR spectroscopy, and elemental analysis, with structural determination confirmed through single-crystal X-ray diffraction. Furthermore, the catalytic properties of these complexes were investigated. All these complexes exhibited excellent catalytic activities for hydroboration of benzaldehyde, among which complex 5 demonstrating excellent catalytic performance (up to 99% yield) with a versatile substrates scope and high tolerance to functional groups (27 substrates) at low catalyst loading (0.8 mol%) under mild reaction conditions.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"92 1","pages":""},"PeriodicalIF":3.5000,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Dalton Transactions","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4dt03395g","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
Five new alkyl zinc complexes supported by different formylfluorenimide ligands were prepared and characterized. Complex 1 was obtained by the reaction of 9-[N(CH3)2-Cy-N=CH]Fl (Cy = 2-cyclohexyl) (Fl = Fluorenyl) (L1) with diethylzinc (ZnEt2) in tetrahydrofuran. By reacting 9-[2-pyridyl-CH-N=CH]Fl (L2) with ZnEt2 in tetrahydrofuran to yield complex 2. Under analogous conditions, complexes 3 and 4 were obtained through the reaction of 9-[2-pyridyl-CH(CH3)-N=CH]Fl (L3) and 9-[8-quinoline-CH-N=CH]Fl(L4) with ZnEt2 in tetrahydrofuran, respectively. The above ligands formed a tridentate four-coordinate structure by introduction of THF molecule along with the elimination of one ethyl group during its coordination with zinc. Notably, the formylfluorenimide ligand 9-[2-phenoxy-Ph-N=CH]Fl(Ph = phenyl) (L5) bearing a phenoxy group exhibited unique reactivity compared to the other ligands, which formed a bidentate three-coordinated structure when reacting with ZnEt2 in THF. All complexes were characterized via 1H NMR, 13C NMR spectroscopy, and elemental analysis, with structural determination confirmed through single-crystal X-ray diffraction. Furthermore, the catalytic properties of these complexes were investigated. All these complexes exhibited excellent catalytic activities for hydroboration of benzaldehyde, among which complex 5 demonstrating excellent catalytic performance (up to 99% yield) with a versatile substrates scope and high tolerance to functional groups (27 substrates) at low catalyst loading (0.8 mol%) under mild reaction conditions.
期刊介绍:
Dalton Transactions is a journal for all areas of inorganic chemistry, which encompasses the organometallic, bioinorganic and materials chemistry of the elements, with applications including synthesis, catalysis, energy conversion/storage, electrical devices and medicine. Dalton Transactions welcomes high-quality, original submissions in all of these areas and more, where the advancement of knowledge in inorganic chemistry is significant.