共查询到20条相似文献,搜索用时 31 毫秒
1.
Dr. Xiangqing Jia Dr. Jörn Nitsch Dr. Lei Ji Zhu Wu Dr. Alexandra Friedrich Florian Kerner Michael Moos Prof. Dr. Christoph Lambert Prof. Dr. Todd B. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10845-10857
The synthesis and characterization of 10-(dimesitylboryl)-N,N-di-p-tolylbenzo[c]phenanthren-4-amine (3-B(Mes)2-[4]helix-9-N(p-Tol)2 1 ) and 13-(dimesitylboryl)-N,N-di-p-tolyldibenzo[c,g]phenanthren-8-amine (3-B(Mes)2-[5]helix-12-N(p-Tol)2 2 ) are reported herein. Their electrochemical and photophysical properties have been studied experimentally and theoretically. The donor and acceptor-substituted helicene derivatives exhibit moderate fluorescence quantum yields in THF (Φf=0.48 and 0.61 for 1 and 2 , respectively), which are higher than unsubstituted ones (Φf=0.18 for [4]helicene; Φf<0.05 for [n]helicenes (n≥5)). In the solid state, the Φf values are higher (Φf=1.00 and 0.55 for 1 and 2 , respectively) than those in solution, most likely due to the restrictions of molecular motions. The S1←S0 transitions of 1 and 2 are predominately HOMO→LUMO transitions. Upon excitation with UV light, the interplanar angle between the two terminal aryl rings of the [5]helix core of 2 decreases (S1 state compared with S0 state), which is similar to placing a spring under an external force. 相似文献
2.
Andrey I. Poddel’sky Vladimir K. Cherkasov Michail P. Bubnov Ludmila G. Abakumova Gleb A. Abakumov 《Journal of organometallic chemistry》2005,690(1):145-150
New square-planar (Ph3P)NiII(o-Tol)(ISQ-Pri) (1), (Ph3P)NiII(o-Tol)(ISQ-Me) (2), (Ph3P)NiII(o-Tol)(ISQ-But) (3) nickel complexes (where ISQ-Pri = 4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-iminobenzosemiquinonate, ISQ-Me = 4,6-di-tert-butyl-N-(2,6-di-methylphenyl)-o-iminobenzosemiquinonate, ISQ-But = 4,6-di-tert-butyl-N-(2,5-di-tert-butylphenyl)-o-iminobenzosemiquinonate, o-Tol = o-tolyl ligand) have been synthesized. Complexes contain σ-bound o-tolyl and neutral donor ligand Ph3P. The sterical hindrances of N-aryl in o-iminobenzosemiquinonate ligands lead to the tetrahedral distortion of square-planar configurations of complexes as it was established using EPR spectroscopy. 相似文献
3.
Shweta Kalra Daniel Pividori Dominik Fehn Chenshu Dai Shicheng Dong Shenglai Yao Jun Zhu Karsten Meyer Matthias Driess 《Chemical science》2022,13(29):8634
Using the potentially tridentate N,N′-bis(N-heterocyclic silylene)pyridine [SiNSi] pincer-type ligand, 2,6-N,N′-diethyl-bis[N,N′-di-tert-butyl(phenylamidinato)silylene] diaminopyridine, led to the first isolable bis(silylene)pyridine-stabilized manganese(0) complex, {κ3-[SiNSi]Mn(dmpe)} 4 (dmpe = (Me2P)2C2H4), which represents an isolobal 17 VE analogue of the elusive Mn(CO)5 radical. The compound is accessible through the reductive dehalogenation of the corresponding dihalido (SiNSi)Mn(ii) complexes 1 (Cl) and 2 (Br) with potassium graphite. Exposing 4 towards the stronger π-acceptor ligands CO and 2,6-dimethylphenyl isocyanide afforded the related Mn(0) complexes κ2-[SiNSi]Mn(CO)3 (5) and κ3-[SiNSi]Mn(CNXylyl)2(κ1-dmpe) (6), respectively. Remarkably, the stabilization of Mn(0) in the coordination sphere of the [SiNSi] ligand favors the d7 low-spin electronic configuration, as suggested by EPR spectroscopy, SQUID measurements and DFT calculations. The suitability of 4 acting as a superior pre-catalyst in regioselective hydroboration of quinolines has also been demonstrated.An isolable bis(silylene)pyridine stabilized manganese(0) complex {κ3-[SiNSi]Mn(dmpe)}, isolobal to elusive Mn(CO)5 radical has been synthesized and fully characterised. 相似文献
4.
Ping Liu 《Tetrahedron》2010,66(3):631-122
Salen and half-salen palladium(II) complexes (salden)Pd (1, salden=N,N′-bis(3,5-di- tert-butylsalicylidene)-1,2-dimethylethylenediamine), (hsalph)PdCl (2, hsalph=3,5-di-tert- butylsalicylidene-1-iminophenylene-2-amine), and (salph)Pd (4, salph=N,N′-bis(3,5-di-tert- butylsalicylidene)-1,2-phenylenediamine) were prepared and structurally characterized by X-ray crystallography. Complex 2 proved to exhibit high catalytic activity toward Suzuki-Miyaura reaction. Polyaromatic C3-symmetric derivatives and various fluorinated biphenyl derivatives were readily achieved in good yields using Suzuki-Miyaura reaction catalyzed by complex 2. 相似文献
5.
G. K. Fukin M. A. Samsonov E. V. Baranov A. I. Poddel’skii V. K. Cherkasov 《Russian Journal of Coordination Chemistry》2017,43(12):858-863
The experimental and theoretical electron densities in complexes [6-(2,6-di-iso-propylphenyl)imino-2,4-di-tert-butylcyclohexa-2,4-diene-1-peroxo-1-olato-N,O,O′]tris(p-chlorophenyl)antimony(V), (p-Cl–C6H4)3Sb(2,6-iso-Pr–Ph–AP) · O2 (I), and [6-(2,6-dimethylphenyl)imino-2,4-di-tert-butylcyclohexa-2,4-diene-1-peroxo-1-olato-N,O,O′]tris(p-chlorophenyl)antimony(V), (p-Cl–C6H4)3Sb(2,6-Me–Ph–AP) · O2 (II), where AP is 4,6-di-tert-butyl-N-o-iminobenzoquinone dianion, are studied on the basis of high-resolution X-ray diffraction data and theoretical calculations using the density functional theory (B3LYP/DGDZVP). The nature of chemical bonds and the charge distribution on atoms are studied, and the energy of molecular oxygen addition to the Sb(V) o-aminophenolate complexes is estimated. The structures are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 1560600 (spherical refinement) and 1560601 (multipole refinement) for complex I; 1560602 (spherical) and 1560603 (multipole) for complex II). 相似文献
6.
G. A. Kostin V. I. Mashukov T. M. Korda S. V. Tkachev V. G. Torgov A. B. Drapailo O. V. Kas’yan V. I. Kal’chenko 《Russian Journal of Inorganic Chemistry》2007,52(11):1697-1703
Complexing [PdCl4]2? with calix[4]arenes (L) functionalized by CH2SR (R = Me (1), n-Bu (2), or p-Tol (3)) in their upper rims has been studied in toluene and CCl4. The stoichiometry of the extracted palladium species (PdCl2) n L, where n = 1 or 2 is established by spectroscopic methods (NMR spectroscopy, UV/Vis spectrophotometry, atomic absorption) and extraction. For slow coordinative extraction, the concentration constants of complex formation and extraction from chloride solutions are determined using the coupled equilibria method. The kinetic and thermodynamic laws of extraction coincide, and their parameters increase in the following row of the substituents at the sulfur atom: p-Tol < Bu < Me. 相似文献
7.
Andrey I. Poddel’sky Nikolay V. Somov Yury A. Kurskii Vladimir K. Cherkasov Gleb A. Abakumov 《Journal of organometallic chemistry》2008,693(21-22):3451-3455
The oxidative addition reaction of 4,6-di-tert-butyl-N-(2-hydroxy-3,5-di-tert-butyl-phenyl)-o-iminobenzoquinone (IBQ) to triphenylantimony(III) proceeds with the migration of hydroxyl-proton to a nitrogen atom to form tridentate O,N,O′-coordinated bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine ligand. In accordance with 1H, 13C, DEPT NMR data, the new hexacoordinate complex [bis-(3,5-di-tert-butyl-phenolate-2-yl)-amine]triphenylantimony(V), [(AP-AP)H]SbPh3 (1) in solution has a Cs symmetry plane leading to the equivalence of two O,N-chelate o-aminophenolato moieties. The molecular structure of 1 · acetone was studied by a single-crystal X-ray. Compound 1 was found to be air-stable both in solid and in solution. Its oxidation by PbO2 leads to paramagnetic [4,6-di-tert-butyl-N-(3,5-di-tert-butyl-phenolate-2-yl)-o-iminobenzosemiquinolato]triphenylantimony(V), [(AP-ISQ)]SbPh3 (2). 相似文献
8.
A. V. Piskunov O. Yu. Trofimova M. S. Piskunova I. V. Smolyaninov N. T. Berberova G. K. Fukin 《Russian Journal of Coordination Chemistry》2018,44(2):138-146
Heptacoordinated tin complexes with pentadentate redox-active ligands containing the diiminopyridine fragment combined with two sterically hindered phenolate coordination centers, LSn-Cl2 and L'SnCl2 (L and L' are dianions of deprotonated 2,6-bis[2,4-di-tert-butyl-6-(methylidenylamino) phenol]pyridine and 2,6-bis[2,4-di-tert-butyl-6-(ethylidenylamino)phenol]pyridine, respectively), are synthesized. The molecular and electronic structures of the synthesized compounds were studied by X-ray diffraction analysis (for complex I, CIF file CCDC no. 1557838), a set of spectral methods, and quantum-chemical calculations. The redox properties of the obtained complexes are characterized by cyclic voltammetry. 相似文献
9.
Alaa A.-M. Abdel-Aziz Serry A.A. El Bialy Takehisa Kunieda 《Tetrahedron letters》2004,45(43):8073-8077
An enantioselective synthesis of sterically congested 1,2-di-tert-butyl and 1,2-di-(1-adamantyl)ethylenediamines has been developed. Thus, diastereomerically pure trans-1-apocamphanecarbonyl-4,5-dimethoxy-2-imidazolidinones 6 and 7 were successfully prepared by optical resolution of (±)-trans-4,5-dimethoxy-2-imidazolidinone using apocamphanecarbonyl chloride (MAC-Cl) followed by stereospecific and stepwise substitution of the dimethoxyl groups using tert-butyl or 1-adamantyl cuprates to provide (4S,5S)-4,5-di-tert-butyl and (4R,5R)-4,5-di-(1-adamantyl)-2-imidazolidinones 12 and 15, respectively. Furthermore, N-acetyl 4,5-di-tert-butyl and 4,5-di-(1-adamantyl)-2-imidazolidinones 16a,b were enantioselectively deacetylated using a catalytic oxazaborolidine system to provide enantiopure 1-p-tolylsulfonyl-4,5-di-tert-butyl-2-imidazolidinones 12 and 19 and 1-p-tolylsulfonyl-4,5-di-(1-adamantyl)-2-imidazolidinones 18 and 20, respectively. Finally, N-p-tolylsulfonyl-2-imidazolidinones 12 and 15 were treated with 30 equiv of Ba(OH)2·8H2O to achieve ring cleavage and to provide (1S,2S)-1,2-di-tert-butylethylenediamine 3 and (1R,2R)-1,2-di-(1-adamantyl)ethylenediamine 4. 相似文献
10.
Lee W. Page Matthew Bailey Paul J. Beswick Simon Frydrych Robert J. Gleave 《Tetrahedron letters》2010,51(26):3388-3391
The discovery of a novel synthesis of new fused bicyclic isoxazoles, for example, N-methyl-3-phenyl-5,6-dihydro-4H-isoxazolo[3,4-c]azepin-8-amine (2a), N-methyl-3-phenyl-4,5-dihydroisoxazolo[3,4-c]pyridin-7-amine (2b) and N-methyl-3-phenyl-4H-pyrrolo[3,4-c]isoxazol-6-amine (2d) in high yield is reported. We speculate that the reaction proceeds via acid-mediated intramolecular 1,3-dipolar cycloaddition from 2-nitro-1,1-ethenediamines 1a,b,d. 相似文献
11.
Sascha Reith Serhiy Demeshko Beatrice Battistella Alexander Reckziegel Christian Schneider Andreas Stoy Crispin Lichtenberg Franc Meyer Dominik Munz C. Gunnar Werncke 《Chemical science》2022,13(26):7907
Imidyl and nitrene metal species play an important role in the N-functionalisation of unreactive C–H bonds as well as the aziridination of olefines. We report on the synthesis of the trigonal imido iron complexes [Fe(NMes)L2]0,− (L = –N{Dipp}SiMe3); Dipp = 2,6-diisopropyl-phenyl; Mes = (2,4,6-trimethylphenyl) via reaction of mesityl azide (MesN3) with the linear iron precursors [FeL2]0,−. UV-vis-, EPR-, 57Fe Mössbauer spectroscopy, magnetometry, and computational methods suggest for the reduced form an electronic structure as a ferromagnetically coupled iron(ii) imidyl radical, whereas oxidation leads to mixed iron(iii) imidyl and electrophilic iron(ii) nitrene character. Reactivity studies show that both complexes are capable of H atom abstraction from C–H bonds. Further, the reduced form [Fe(NMes)L2]− reacts nucleophilically with CS2 by inserting into the imido iron bond, as well as electrophilically with CO under nitrene transfer. The neutral [Fe(NMes)L2] complex shows enhanced electrophilic behavior as evidenced by nitrene transfer to a phosphine, yet in combination with an overall reduced reactivity.A pair of trigonal imido iron complexes ([Fe(NMes)L2]0,−) in two oxidation states is reported. The anionic complex K{crypt.222}[Fe(NMes)L2] is best described as an iron(ii) imide. 相似文献
12.
[Pd(C6F5)2(CNR)2] (R = Cy, But, p-MeC6H4 (p-Tol)) react with [PdCl2(NCPh)2] to give [Pd2(μ-Cl)2(C6F5)2(CNR)2]. In refluxing benzene insertion of isocyanide into the C6F5Pd bonds occurs only for R = p-Tol, to give a imidoyl bridged polynuclear complex cis-[Pd2 (μ-Cl)2[μ-C(C6F5) = N(Tol-p)]2n]. This complex reacts with (a) Tl(acac) to give [Pd2{μ-C(C6F5) = N(Tol-p)}2(acac)2]; (b) neutral monodentate ligands to afford dimeric complexes [Pd2{μ-C(C6F5) = N(Tol-p)}2Cl2L2] (L = NMe3, py, 4-Me-py, SC4H8), and (c) isocyanides to give insoluble complexes of the same composition which are thought to be polymeric, [(CNR)Cl{μ-C(C6F5) = (p-Tol)}]n (R = p-Tol, Me, But). Thermal decomposition of cis-[Pd2 (μ-Cl)2 [μ-C(C6F5) = N( p-Tol)]2n] gives the diazabutadiene species (p-Tol)NC(C6F5)C(C6F5)N(p-Tol) in high yield. 相似文献
13.
Rui Guo Xin Zhang Tong Li Qianli Li David A. Ruiz Liu Leo Liu Chen-Ho Tung Lingbing Kong 《Chemical science》2022,13(8):2303
A cationic terminal iminoborane [Mes*N B ← IPr2Me2][AlBr4] (3+[AlBr4]−) (Mes* = 2,4,6-tri-tert-butylphenyl and IPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) has been synthesized and characterized. The employment of an aryl group and N-heterocyclic carbene (NHC) ligand enables 3+[AlBr4]− to exhibit both B-centered Lewis acidity and BN multiple bond reactivities, thus allowing for the construction of tri-coordinate boron cations 5+–12+. More importantly, initial reactions involving coordination, addition, and [2 + 3] cycloadditions have been observed for the cationic iminoborane, demonstrating the potential to build numerous organoboron species via several synthetic routes.An NHC-stabilized aryliminoboryl cation exhibits both boron-centered Lewis acidity and multiple bond reactivity and could be utilized as an effective synthon for unusual cationic boron species. 相似文献
14.
Carlos Camacho-Camacho Maria E. Castillo-Ramos Aurora Vásquez-Badillo Angelina Flores-Parra Rosalinda Contreras 《Journal of organometallic chemistry》2010,695(6):833-9863
The syntheses of [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]diphenyltin (1) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]dichloro-phenyl-stannate (2) by template reactions using 3,5-di-tert-butylcatechol, aqueous ammonia and SnPh2Cl2 are reported. We also report the syntheses of compounds 2, [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]trichloro-stannate (4), [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)methylamine]chloro-methyltin (5), and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)-n-butylamine]n-butyl-chlorotin (6) and [bis(3,5-di-tert-butyl-2-hydroxy-2-phenyl)amine]n-butyl-dichloro-stannate (7), performed by transmetallation reactions of the octahedral zinc coordination compound Zn[3,5-di-tert-butyl-1,2-quinone-(3,5-di-tert-butyl-2-hydroxy-1-phenyl)imine]2 (3) with SnPhCl3 or SnPh2Cl2, SnCl4, SnMe2Cl2, Sn(nBu)2Cl2 and Sn(nBu)Cl3, respectively. The X-ray diffraction structures of compounds 1, 2, 4 and 6 are reported. The transmetallation reactions with Sn(alkyl)2Cl2 afforded pentacoordinated tin compounds, where an alkyl group migrated from tin to nitrogen, while similar reactions with Sn-Ph compounds did not present any phenyl group migration. 相似文献
15.
16.
Arpita Banerjee Averi Guha Pali Maiti Somen Goswami Tanmay Chattopadhyay Tapan Kumar Mondal Santanu Bhattacharya Ennio Zangrando Debasis Das 《Transition Metal Chemistry》2011,36(8):829-839
Three Ni(II) complexes of cresol-based Schiff-base ligands, namely [Ni2(L1)(NCS)3(H2O)2], (1) [Ni2(L2)(CH3COO)(NCS)2(H2O)] (2) and [Ni2(L3)(NCS)3] (3), (where L1 = 2,6-bis(N-ethylpyrrolidineiminomethyl)-4-methylphenolato, L2 = 2,6-bis(N-ethylpiperidineiminomethyl)-4-methylphenolato and L3 = 2,6-bis{N-ethyl-N-(3-hydroxypropyl iminomethyl)}-4-methylphenolato), have been synthesized and structurally characterized by X-ray single-crystal diffraction in addition to routine physicochemical techniques. Density functional theory calculations have been performed to understand the nature of the electronic spectra of the complexes. Complexes 1?C3 when reacted with 4-nitrophenyl phosphate in 50:50 acetonitrile?Cwater medium promote the cleavage of the O?CP bond to form p-nitrophenol and smoothly convert 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) either in MeOH or in MeCN medium. Phosphatase- and catecholase-like activities were monitored by UV?Cvis spectrophotometry and the Michaelis?CMenten equation was applied to rationalize all the kinetic parameters. Upon treatment with urea, complexes 1 and 2 give rise to [Ni2(L1)(NCS)2(NCO)(H2O)2] (1??) and [Ni2(L2)(CH3COO)(NCO)(NCS)(H2O)] (2??) derivatives, respectively, whereas 3 remains unaltered under same reaction conditions. 相似文献
17.
Effect of the solvent nature on the kinetics of photoreduction of substituted benzoquinones in the presence of hydrogen donors has been studied. It has been found that the effective photoreduction rate constant (kH) for quinones decreases with an increase in solvent polarity. For the 3,6-di-tert-butylbenzoquinone–1,2-N,N-dimethylaniline pair, the dependence of ln kH on the difference of the reciprocals of optical and static solvent permitivities (1/ε ∞–1/ε0) is stepwise with a break point corresponding to CH2Cl2. A similar relationship lnkH = f(1/ε ∞–1/ε0) is observed for the p-chloranil–mesitylene pair. In the study of the photoreduction kinetics for a series of seven o-benzoquinones in the presence of p-derivatives of N,N-dimethylaniline in CH2Cl2, it has been found that the dependence of kH on the free energy of electron transfer (ΔGe) has a maximum for the 3,6-di-tert-butylquinone-1,2–N,N-dimethylaniline pair at ΔGe = 0.11 eV. 相似文献
18.
Philipp W. Kamm Leona L. Rodrigues Sarah L. Walden James P. Blinco Andreas-Neil Unterreiner Christopher Barner-Kowollik 《Chemical science》2022,13(2):531
We exploit two reactive chromophores to establish sequence-independent photochemical activation, employing ortho-methyl benzaldehyde (oMBA) and N,N-(dimethylamino)pyrene aryl tetrazole (APAT) with N-(2-hydroxy)ethyl maleimide (NHEM), without any additives. Critically, the order of the irradiation sequence is irrelevant, as the shorter wavelength does not activate the higher wavelength activated species. Therefore, full sequence-independent λ-orthogonality is achieved through differences in both the reaction quantum yields (Φr,oMBA and Φr,APAT) and wavelength-dependent reactivity profiles of the employed chromophores.We exploit two reactive chromophores to establish sequence-independent photochemical activation without any additives. 相似文献
19.
Treatment of LZrCl2 (L=N,N′-ethylenebis(3,5-di-tert-butylsalicylideneiminato) (1), N,N′-o-phenylenebis(3,5-di-tert-butylsalicylideneiminato) (2)), which is an effective catalyst precursor for ethylene oligomerization, with 1.5 equiv of water in toluene afforded H2O-coordinating salen-type zirconium complexes [LZrCl2(H2O)]. The effects of the content of H2O and the temperature on the equilibrium of association and disassociation of H2O molecule in [LZrCl2(H2O)n] (n=0, 1) were studied in solution (CDCl3) by 1H NMR spectroscopy. The crystal and molecular structure of [1(H2O)] was determined by X-ray diffraction analysis, which revealed that a herringbone supramolecular assembly was constructed in the crystalline state of [1(H2O)], stacked by the intermolecular hydrogen bonds between the OH group of the coordinating H2O and one of the chloride ligands. 相似文献
20.
N. S. Emel’yanova A. F. Shestakov N. A. Sanina S. M. Aldoshin 《Russian Chemical Bulletin》2013,62(2):355-362
The reduced forms of Roussin’s red esters [Fe2(μ-RS)2(NO)4]n? (n = 1, 2; R = Ph, Pr) and their possible decomposition products were studied by quantum chemical calculations. The energy diagram of the processes that occur in a dichloromethane solution was constructed. According to this diagram, the monoanions are much more stable than the corresponding dianions. Possible dissociation paths of the dianions in solution were proposed. The anions with the propyl ligand are more stable than the anions with the phenyl ligand. 相似文献