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CAS: 1191914-75-6
MF: C20N2O+.Br-
MW: 364.1308
Synonyms:
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HaiBin Song

Nankai Univerisity
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Baiquan Wang

Nankai University
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Ruthenium Ring-Opening Metathesis Polymerization Catalysts Bearing o- Aryloxide-N-Heterocyclic Carbenes
Co-reporter: Yong Kong;Yungang Tang;Zunzhi Wang;Shansheng Xu;Haibin Song;Baiquan Wang
pp: 492-498
Publication Date(Web):
DOI: 10.1002/macp.201200509

Abstract

A series of o-aryloxide-N-heterocyclic carbene ruthenium complexes 2–4 is synthesized via sequential reactions of the o-hydroxyaryl imidazolium proligands (2-OH-3,5-tBu2C6H2)(R)(C3H3N2)+Br− (R = Me (1a), iPr (1b), Mes (1c)) with Ag2O and [(C6H6)RuCl2]2. All of the complexes are characterized by 1H and 13C NMR spectroscopy, high-resolution mass spectrometry (HRMS), and elemental analysis. The molecular structure of 2 is determined by single-crystal X-ray diffraction analysis. The ring-opening metathesis polymerization (ROMP) of norbornene (NBE) with 2–4 is studied. Among them, complex 4 exhibits the highest activity and efficiency toward ROMP of NBE at 85 °C without any cocatalyst, and the resultant polymers have very high molecular weight (>106 Da) and narrow molecular weight distributions. This complex can also efficiently catalyze the alternating copolymerization of NBE and cyclooctene.

Synthesis, structures, and norbornene polymerization behavior of C(sp3), N-chelated palladacycles bearing o-aryloxide-N-heterocyclic carbene ligands
Co-reporter: Liang Dang, Jing Guo, Haibin Song, Binyuan Liu and Baiquan Wang  
pp: 17177-17183
Publication Date(Web):24 Sep 2014
DOI: 10.1039/C4DT02198C
Treatment of the o-hydroxyaryl imidazolium pro-ligands (2-OH-3,5-tBu2C6H2)(R)(C3H3N2)+Br− [R = Mes (1a), Ph (1b), iPr (1c), Me (1d)] with Ag2O afforded the corresponding silver complexes 2a–d. Subsequent metal-exchange reactions of 2a–d with [Pd(OAc)(8-Me-quin-H)]2 (3) yielded the desired C(sp3), N-chelated and o-aryloxide-NHC-ligated palladacycle complexes 4a–d in 60–80% yields. When the N-tert-butyl substituted o-hydroxyaryl imidazolium pro-ligand 1e reacted with 3 in the presence of K2CO3 in dioxane, the palladacycle complex 4e, in which the NHC adopted an abnormal binding (C4-bonding), was obtained in 20% yield. All these complexes were fully characterized using 1H and 13C NMR spectra, high-resolution mass spectrometry (HRMS), and elemental analysis. Single-crystal X-ray diffraction analysis results further confirmed the molecular structures of 4a–c and the abnormal binding of NHC in 4e. With methylaluminoxane (MAO) as the cocatalyst these palladacycles showed excellent catalytic activities of up to 107 g of PNB (mol of Pd)−1 h−1 in the addition polymerization of norbornene.
Synthesis, structures, and norbornene polymerization behavior of C(sp3), N-chelated palladacycles bearing o-aryloxide-N-heterocyclic carbene ligands
Co-reporter: Liang Dang, Jing Guo, Haibin Song, Binyuan Liu and Baiquan Wang
pp: NaN17183-17183
Publication Date(Web):2014/09/24
DOI: 10.1039/C4DT02198C
Treatment of the o-hydroxyaryl imidazolium pro-ligands (2-OH-3,5-tBu2C6H2)(R)(C3H3N2)+Br− [R = Mes (1a), Ph (1b), iPr (1c), Me (1d)] with Ag2O afforded the corresponding silver complexes 2a–d. Subsequent metal-exchange reactions of 2a–d with [Pd(OAc)(8-Me-quin-H)]2 (3) yielded the desired C(sp3), N-chelated and o-aryloxide-NHC-ligated palladacycle complexes 4a–d in 60–80% yields. When the N-tert-butyl substituted o-hydroxyaryl imidazolium pro-ligand 1e reacted with 3 in the presence of K2CO3 in dioxane, the palladacycle complex 4e, in which the NHC adopted an abnormal binding (C4-bonding), was obtained in 20% yield. All these complexes were fully characterized using 1H and 13C NMR spectra, high-resolution mass spectrometry (HRMS), and elemental analysis. Single-crystal X-ray diffraction analysis results further confirmed the molecular structures of 4a–c and the abnormal binding of NHC in 4e. With methylaluminoxane (MAO) as the cocatalyst these palladacycles showed excellent catalytic activities of up to 107 g of PNB (mol of Pd)−1 h−1 in the addition polymerization of norbornene.