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1.
Andreas Kapelski Jun Okuda 《Journal of polymer science. Part A, Polymer chemistry》2013,51(23):4983-4991
Ring‐opening polymerization of rac‐ and meso‐lactide initiated by indium bis(phenolate) isopropoxides {1,4‐dithiabutanediylbis(4,6‐di‐tert‐butylphenolate)}(isopropoxy)indium ( 1 ) and {1,4‐dithiabutanediylbis(4,6‐di(2‐phenyl‐2‐propyl)phenolate)}(isopropoxy)indium ( 2 ) is found to follow first‐order kinetics for monomer conversion. Activation parameters ΔH? and ΔS? suggest an ordered transition state. Initiators 1 and 2 polymerize meso‐lactide faster than rac‐lactide. In general, compound 2 with the more bulky cumyl ortho‐substituents in the phenolate moiety shows higher polymerization activity than 1 with tert‐butyl substituents. meso‐Lactide is polymerized to syndiotactic poly(meso‐lactides) in THF, while polymerization of rac‐lactide in THF gives atactic poly(rac‐lactides) with solvent‐dependent preferences for heterotactic (THF) or isotactic (CH2Cl2) sequences. Indium bis(phenolate) compound rac‐(1,2‐cyclohexanedithio‐2,2′‐bis{4,6‐di(2‐phenyl‐2‐propyl)phenolato}(isopropoxy)indium ( 3 ) polymerizes meso‐lactide to give syndiotactic poly(meso‐lactide) with narrow molecular weight distributions and rac‐lactide in THF to give heterotactically enriched poly(rac‐lactides). © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4983–4991 相似文献
2.
Francesco De Carlo Carmine Capacchione Vincenzo Schiavo Antonio Proto 《Journal of polymer science. Part A, Polymer chemistry》2006,44(4):1486-1491
The isospecific polymerization of several para‐substituted styrenes was performed in the presence of the catalyst dichloro[1,4‐dithiabutanediyl‐2,2′‐bis(4,6‐di‐tert‐butyl‐phenoxy)]titanium activated by methylaluminoxane. All the polymers were highly regioregular and isotactic with narrow molecular weight distributions. The presence of electron‐donating substituents on the aromatic ring had a positive effect on the catalyst activity, whereas electron‐withdrawing substituents affected the polymerization activity negatively. Binary copolymerizations of the various substituted styrenes showed an inversion of the reactivity with respect to that observed in the homopolymerization. These results suggested that the last monomer unit of the polymer chain coordinated to the metal center, influencing the reactivity of the catalyst with respect to the incoming monomer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1486–1491, 2006 相似文献
3.
Koichi Shinohara Prof. Dr. Hayato Tsurugi Prof. Dr. Reiner Anwander Prof. Dr. Kazushi Mashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(62):14130-14136
The rare-earth metal complexes Ln( L1 )[N(SiHMe2)2](thf) (Ln=La, Ce, Y; L1 =N,N′′-bis(pentafluorophenyl)diethylenetriamine dianion) were synthesized by treating Ln[N(SiHMe2)2]3(thf)2 with L1 H2. The lanthanum and cerium derivatives are active catalysts for the hydrosilylation of benzophenone derivatives with HN(SiHMe2)2. An amine-exchange reaction was revealed as a key step of the catalytic cycle, in which Ln−Si−H β-agostic interactions are proposed to promote insertion of the carbonyl moiety into the Si−H bond. 相似文献
4.
Dr. Paul Benndorf Dipl.‐Chem. Jochen Kratsch Larissa Hartenstein Dipl.‐Chem. Corinna M. Preuss Prof. Dr. Peter W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(45):14454-14463
The treatment of the recently reported potassium salt (S)‐N,N′‐bis‐(1‐phenylethyl)benzamidinate ((S)‐KPEBA) and its racemic isomer (rac‐KPEBA) with anhydrous lanthanide trichlorides (Ln=Sm, Er, Yb, Lu) afforded mostly chiral complexes. The tris(amidinate) complex [{(S)‐PEBA}3Sm], bis(amidinate) complexes [{Ln(PEBA)2(μ‐Cl)}2] (Ln=Sm, Er, Yb, Lu), and mono(amidinate) compounds [Ln(PEBA)(Cl)2(thf)n] (Ln=Sm, Yb, Lu) were isolated and structurally characterized. As a result of steric effects, the homoleptic 3:1 complexes of the smaller lanthanide atoms Yb and Lu were not accessible. Furthermore, chiral bis(amidinate)–amido complexes [{(S)‐PEBA}2Ln{N(SiMe3)2}] (Ln=Y, Lu) were synthesized by an amine‐elimination reaction and salt metathesis. All of these chiral bis‐ and tris(amidinate) complexes had additional axial chirality and they all crystallized as diastereomerically pure compounds. By using rac‐PEBA as a ligand, an achiral meso arrangement of the ligands was observed. The catalytic activities and enantioselectivities of [{(S)‐PEBA}2Ln{N(SiMe3)2}] (Ln=Y, Lu) were investigated in hydroamination/cyclization reactions. A clear dependence of the rate of reaction and enantioselectivity on the ionic radius was observed, which showed higher reaction rates but poorer enantioselectivities for the yttrium compound. 相似文献
5.
Xiaoping Xu Yingming Yao Mingyu Hu Yong Zhang Qi Shen 《Journal of polymer science. Part A, Polymer chemistry》2006,44(15):4409-4419
Lanthanide isopropoxides supported by carbon‐bridged bisphenolate ligands of 2,2′‐ethylene‐bis(4,6‐di‐tert‐butylphenoxo) {[(EDBP)Ln(μ‐OPri)(THF)2]2, where Ln is Nd ( 1 ), Sm ( 2 ), or Yb ( 3 ) and THF is tetrahydrofuran} were synthesized by protic exchange reactions in high yields with Cp3Ln compounds as raw materials, and complex 1 was structurally characterized. Complexes 1 – 3 were shown to be efficient initiators for the ring‐opening polymerization of ε‐caprolactone (ε‐CL) and 2,2‐dimethyltrimethylene carbonate (DTC). Complexes 1 – 3 could initiate the controlled polymerization of ε‐CL, and the polymerization rate was first‐order with respect to the monomer. The influence of the reaction conditions on the monomer conversion, molecular weight, and molecular weight distribution of the resultant polymers was investigated. End‐group analyses of the oligomers of ε‐CL and DTC showed that the polymerization underwent a coordination–insertion mechanism. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4409–4419, 2006 相似文献
6.
Immo Weber Frank W. Heinemann Panagiotis Bakatselos Ulrich Zenneck 《Helvetica chimica acta》2007,90(4):834-845
A pressure‐controlled procedure for the SN1 reaction of rac‐1‐[(dimethylamino)methyl]‐2‐(tributylstannyl)ferrocene ( 1 ) to rac‐1‐(phthalimidomethyl)‐2‐(tributylstannyl)ferrocene ( 2 ) was developed. Pd0‐Catalyzed Stille coupling of 2 with iodobenzene afforded rac‐1‐phenyl‐2‐(N‐phthalimidomethyl)ferrocene ( 5 ) in 74% yield; after trace enrichment by crystallization of the combined mother liquors, one single crystal of each, 5 , catalysis intermediate trans‐iodo(σ‐phenyl)bis(triphenylarsino)palladium(II) ( 7 ), trans‐diiodobis(triphenylarsino)palladium(II) ( 8 ), and rac‐2,2′‐bis(phthalimidomethyl)‐1,1′‐biferrocene ( 9 ) could be isolated by crystal sorting under a microscope and characterized by X‐ray crystal structure analysis. Furthermore, 5 was deprotected to amine ( 11 ), which does even survive the Birch reduction to rac‐1‐(aminomethyl)‐2‐(cyclohexa‐2,5‐dienyl)ferrocene ( 12 ). 相似文献
7.
Jin Yang Jian‐Fang Ma Ying‐Ying Liu 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):m101-m103
The title complex, [μ‐2,2′‐(1,4‐butanediyl)di‐1H‐benzimidazole‐κ2N3:N3′]bis{[2,2′‐(1,4‐butanediyl)di‐1H‐benzimidazole‐κ2N3,N3′](nitrato‐κO)cobalt(II)} dinitrate ethanol disolvate, [Co2(NO3)2(C18H18N4)3](NO3)2·2C2H6O, was obtained from self‐assembly of cobalt(II) nitrate with 2,2′‐(1,4‐butanediyl)dibenzimidazole (L). The complex molecule lies about an inversion centre and the flexible L ligands act in both bridging and chelating modes to form a dinuclear complex with unanticipated nine‐membered chelate rings. The unique uncoordinated nitrate anion is linked to the cation by pairs of N—H⋯O hydrogen bonds, which determine the overall cation conformation. Cation–anion sets are then linked by a further N—H⋯O hydrogen bond to generate a chain along [010]. Chains are linked by C—H⋯O hydrogen bonds to form sheets in the (100) plane. 相似文献
8.
DeborahF. dosSantos Mario Argentini Regin Weinreich Hans‐Jürgen Hansen 《Helvetica chimica acta》2000,83(11):2926-2938
We synthesized 2′‐carbaboranyl‐2,5′‐bi‐1H‐benzimidazoles containing 10 B‐atoms and labeled with Se or the positron‐emitting radionuclide 73Se (t1/2=7.1 h), with a view to their application to cancer treatment by boron‐neutron‐capture therapy (BNCT) and to compound‐distribution measurements in vivo by positron‐emission tomography (PET). Thus, 2,2′‐{{2′‐{4‐[1,2‐dicarba‐closo‐dodecaboran(12)‐2‐ylmethoxy]phenyl}‐[2,5′‐bi‐1H‐benzimidazol]‐5‐yl}imino}bis[ethanol] ( 26c ) was obtained by the reaction of 2,2′‐[(3,4‐diaminophenyl)imino]bis[ethanol] ( 19 ) with ethyl 2‐{4‐[1,2‐dicarba‐closo‐dodecaboran(12)‐2‐ylmethoxy]phenyl}‐1H‐benzimidazole‐5‐carboximidate hydrochloride ( 25 ), as well as the analogues 26a and 26b (Scheme 6). Tosylation of compound 26c gave 4 regioisomers 27a – d , which, after selenation, produced 2′‐{4‐[1,2‐dicarba‐closo‐dodecaboran(12)‐2‐ylmethoxy]phenyl}‐5‐(tetrahydro‐2H‐1,4‐selenazin‐4‐yl)‐2,5′‐bi‐1H‐benzimidazole ( 29 ) in 42% yield (Scheme 7). 相似文献
9.
Gyo Jic Shin Jin Chul Jung Jun Ho Chi Tae Hwan Oh Jin Beak Kim 《Journal of polymer science. Part A, Polymer chemistry》2007,45(5):776-788
A novel positive‐working, photosensitive polyimide, poly[1,4‐phenyleneoxy‐1,4‐phenylene‐2,2′‐di(2‐nitrobenzyloxy)benzophenone‐3,3′,4,4′‐tetracarboxdiimide] (OPI‐Nb), developable with an aqueous base was prepared by the o‐nitrobenzylation of a polyimide, poly(1,4‐phenyleneoxy‐1,4‐phenylene‐2,2′‐dihydroxybenzophenone‐3,3′,4,4′‐tetracarboxdiimide) (OPI), derived from 2,2′‐dihydroxy‐3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (DHBA) and 4,4′‐oxydianiline, and it micropatterning properties were investigated. The o‐nitrobenzylation of OPI to OPI‐Nb was conducted with o‐nitrobenzyl bromide in N‐methyl‐2‐pyrrolidinone containing Et3N. The DHBA monomer was synthesized by exhaustive KMnO4 oxidation of bis(2‐dimethoxy‐3,4‐dimethylphenyl)methane obtained by etherification of bis(2‐hydroxy‐3,4‐dimethylphenyl)methane with iodomethane, followed by deprotection of the methoxy groups and cyclodehydration of the obtained 2,2′‐dihydroxy‐3,3′4,4′‐benzophenonetetracarboxylic acid. The intermediate bis(2‐hydroxy‐3,4‐dimethylphenyl)methane was prepared by the condensation of 2,3‐dimethylphenol with paraformaldehyde. The degree of o‐nitrobenzylation was determined to be over 94 mol % from 1H NMR absorption of benzylic CH2 protons. The aromatic OPI was perfectly soluble in a dilute aqueous NaOH solution and tetramethylammonium hydroxide (TMAH), whereas OPI‐Nb was not even swellable in them. In the micropatterning process, OPI‐Nb showed a line‐width resolution of 0.4‐μm and a sensitivity of 5.4 J/cm2 when its thin films were irradiated with 365‐nm light and developed with a 2.38% aqueous TMAH solution at room temperature for 90 s. The thickness loss of OPI‐Nb films measured after postbaking at 350 °C was in the 8–9% range. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 776–788, 2007 相似文献
10.
2, 2′‐Bromomethyl‐1, 1′‐binaphthyl reacted with di‐tert‐butylphosphine to form (R, S)‐4, 4‐di‐tert‐butyl‐4, 5‐dihydro‐3Hdinaphtho[2, 1‐c:1′, 2′‐e] phosphepinium bromide 5a . The di‐iso‐propyl‐ ( 5b) and the phenyl‐ethyl ( 5c ) analogue of compound 5a were prepared by similar routes. Treatment of 5a with potassium diphenylphosphide, KPPh2, afforded the corresponding bis‐phosphine, 2‐di‐tert‐butylphosphino‐methyl‐2′‐diphenylphosphino‐methyl‐1, 1′‐binaphthyl 6 . An attempt at the synthesis of the first example of a bis‐phosphonite ligand with a 2, 2′‐dimethyl‐1, 1′‐binaphthyl backbone unexpectedly led, in the first step, to 2, 2′‐bis[diethylamino‐methoxy‐phosphino]‐1, 1′‐binaphthyl 9 . X‐ray crystal structure analyses were carried out for the phosphepinium bromides 5a and 5c , and for the bis‐phosphines 6 and 9 . In compounds 5a and 5c the interplanar angle between the two parts of the binaphthyl group is 65.8° and 64.5°, respectively, as reflected in the conformation of the seven‐membered ring. In 5a the bromide and methanol residues are hydrogen‐bonded to form Br— (···HOCH3)2 units. In 6 the binaphthyl interplanar angle is 86.1°; the two halves of the molecule show appreciably different conformations of the ring substituents, as do those of 9 (binaphthyl angle 78.6°). 相似文献
11.
Chao Bai Bin Liu Huai-Ming Hu Jin-Dian Li Xiaofang Wang Ganglin Xue 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(4):422-432
Three series of lanthanide coordination polymers, namely catena‐poly[[lanthanide(III)‐μ2‐(benzene‐1,2‐dicarboxylato)‐μ2‐[2‐(2,2′:6′,2′′‐terpyridin‐4′‐yl)benzoato]] monohydrate], {[Ln(C8H4O4)(C22H14N3O2)]·H2O}n or {[Ln(1,2‐bdc)(L)]·H2O}n, with lanthanide (Ln) = dysprosium (Dy, 1 ), holmium (Ho, 2 ) and erbium (Er, 3 ), poly[bis(μ2‐benzene‐1,3‐dicarboxylato)bis[μ2‐2‐(2,2′:6′,2′′‐terpyridin‐4′‐yl)benzoato]dilanthanide(III)], [Ln2(C8H4O4)2(C22H14N3O2)2]n or [Ln2(1,3‐bdc)2(L)2]n, with Ln = gadolinium (Gd, 4 ), Ho ( 5 ) and Er ( 6 ), and poly[(μ2‐benzene‐1,4‐dicarboxylato)[μ2‐2‐(2,2′:6′,2′′‐terpyridin‐4′‐yl)benzoato]lanthanide(III)], [Ln(C8H4O4)(C22H14N3O2)]n or [Ln(1,4‐bdc)(L)]n, with Ln = Dy ( 7 ), Ho ( 8 ), Er ( 9 ) and ytterbium (Yb, 10 ), were synthesized under hydrothermal conditions and characterized by elemental analysis, IR and single‐crystal X‐ray diffraction. Compounds 1 – 3 possess one‐dimensional loop chains with Ln2(COO)2 units, which are extended into three‐dimensional (3D) supramolecular structures by π–π interactions. Isostructural compounds 5 and 6 show 6‐connected 3D networks, with pcu topology consisting of Ln2(COO)2 units. Compounds 7 – 10 display 8‐connected 3D frameworks with the topological type rob , consisting of Ln2(COO)2 units. The influence of the coordination orientations of the aromatic dicarboxylate groups on the crystal structures is discussed. 相似文献
12.
High‐Contrast Red–Green–Blue Tricolor Fluorescence Switching in Bicomponent Molecular Film
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Hyeong‐Ju Kim Dr. Dong Ryeol Whang Chong Han Lee Prof. Soo Young Park 《Angewandte Chemie (International ed. in English)》2015,54(14):4330-4333
Highly efficient red–green–blue (RGB) tricolor luminescence switching was demonstrated in a bicomponent solid film consisting of (2Z,2′Z)‐2,2′‐(1,4‐phenylene)bis(3‐(4‐butoxyphenyl)acrylonitrile) (DBDCS) and (2Z,2′Z)‐3,3′‐(2,5‐bis(6‐(9H‐carbazol‐9‐yl)hexyloxy)‐1,4‐phenylene)bis(2‐(3,5‐bis(trifluoromethyl)phenyl)acrylonitrile) (m‐BHCDCS). Reversible RGB luminescence switching with a high ratiometric color contrast (λem=594, 527, 458 nm for red, green, and blue, respectively) was realized by different external stimuli such as heat, solvent vapor exposure, and mechanical force. It was shown that Förster resonance energy transfer in the bicomponent mixture could be efficiently switched on and off through supramolecular control. 相似文献
13.
Tandem aza‐Wittig reaction of iminophosphorane with 1, 4‐phenylene diisocyanate followed by intramolecular heteroconjugate addition annulation after addition of a nucleophilic reagent (amine, phenol, and alcohol), in the presence of catalytic K2CO3 or NaOR, gives selectively the functionalized substituted 2, 2′‐di(alkylamino, aryloxy)‐3, 3′‐(1, 4‐phenylene)bis(thieno[3, 2‐d]pyrimidin‐4(3H)‐ones) and 2, 2′‐di(alkylamino or alkoxy)‐3, 3′‐(1, 4‐phenylene)bis(3, 5, 6, 7‐tetrahydro‐4H‐cyclopenta[4, 5]thieno[2, 3‐d]pyrimidin‐4‐ones). 相似文献
14.
Dr. Xiao‐Qiang Yu Tomohiko Shirai Dr. Yasunori Yamamoto Prof. Dr. Norio Miyaura 《化学:亚洲杂志》2011,6(3):932-937
Rhodium‐catalyzed 1,4‐addition of lithium 5‐methyl‐2‐furyltriolborate ([ArB(OCH2)3CCH3]Li, Ar=5‐methyl‐2‐furyl) to unsaturated ketones to give β‐furyl ketones was followed by ozonolysis of the furyl ring for enantioselective synthesis of γ‐oxo‐carboxylic acids. [Rh(nbd)2]BF4 (nbd=2,5‐norbornadiene) chelated with 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (binap) or 2,3‐bis(diphenylphosphino)butane (chiraphos) gave high yields and high selectivities in a range of 91–99 % ee at 30 °C in a basic dioxane/water solution. The corresponding reaction of unsaturated esters, such as methyl crotonate, had strong resistance under analogous conditions, but the 1,4‐adduct was obtained in 70 % yield and with 94 % ee when more electron‐deficient phenyl crotonate was used as the substrate. 相似文献
15.
Dr. Sebastien Meiries Dr. Gaëtan Le Duc Dr. Anthony Chartoire Dr. Alba Collado Klaus Speck Kasun S. Athukorala Arachchige Prof. Dr. Alexandra M. Z. Slawin Prof. Dr. Steven P. Nolan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17358-17368
A straightforward and scalable eight‐step synthesis of new N‐heterocyclic carbenes (NHCs) has been developed from inexpensive and readily available 2‐nitro‐m‐xylene. This process allows for the preparation of a novel class of NHCs coined ITent (“Tent” for “tentacular”) of which the well‐known IMes (N,N′‐bis(2,4,6‐trimethylphenyl)imidazol‐2‐ylidene), IPr (N,N′‐bis(2,6‐di(2‐propyl)phenyl)imidazol‐2‐ylidene) and IPent (N,N′‐bis(2,6‐di(3‐pentyl)phenyl)imidazol‐2‐ylidene) NHCs are the simplest and already known congeners. The synthetic route was successfully used for the preparation of three members of the ITent family: IPent (N,N′‐bis(2,6‐di(3‐pentyl)phenyl)imidazol‐2‐ylidene), IHept (N,N′‐bis(2,6‐di(4‐heptyl)phenyl)imidazol‐2‐ylidene) and INon (N,N′‐bis(2,6‐di(5‐nonyl)phenyl)imidazol‐2‐ylidene). The electronic and steric properties of each NHC were studied through the preparation of both nickel and palladium complexes. Finally the effect of these new ITent ligands in Pd‐catalyzed Suzuki–Miyaura and Buchwald–Hartwig cross‐couplings was investigated. 相似文献
16.
Dominique Robert Dr. Elise Abinet Dipl.‐Chem. Thomas P. Spaniol Dr. Jun Okuda Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(44):11937-11947
Monocationic bis‐allyl complexes [Ln(η3‐C3H5)2(thf)3]+[B(C6X5)4]? (Ln=Y, La, Nd; X=H, F) and dicationic mono‐allyl complexes of yttrium and the early lanthanides [Ln(η3‐C3H5)(thf)6]2+[BPh4]2? (Ln=La, Nd) were prepared by protonolysis of the tris‐allyl complexes [Ln(η3‐C3H5)3(diox)] (Ln=Y, La, Ce, Pr, Nd, Sm; diox=1,4‐dioxane) isolated as a 1,4‐dioxane‐bridged dimer (Ln=Ce) or THF adducts [Ln(η3‐C3H5)3(thf)2] (Ln=Ce, Pr). Allyl abstraction from the neutral tris‐allyl complex by a Lewis acid, ER3 (Al(CH2SiMe3)3, BPh3) gave the ion pair [Ln(η3‐C3H5)2(thf)3]+[ER3(η1‐CH2CH?CH2)]? (Ln=Y, La; ER3=Al(CH2SiMe3)3, BPh3). Benzophenone inserts into the La? Callyl bond of [La(η3‐C3H5)2(thf)3]+[BPh4]? to form the alkoxy complex [La{OCPh2(CH2CH?CH2)}2(thf)3]+[BPh4]?. The monocationic half‐sandwich complexes [Ln(η5‐C5Me4SiMe3)(η3‐C3H5)(thf)2]+[B(C6X5)4]? (Ln=Y, La; X=H, F) were synthesized from the neutral precursors [Ln(η5‐C5Me4SiMe3)(η3‐C3H5)2(thf)] by protonolysis. For 1,3‐butadiene polymerization catalysis, the yttrium‐based systems were more active than the corresponding lanthanum or neodymium homologues, giving polybutadiene with approximately 90 % 1,4‐cis stereoselectivity. 相似文献
17.
Mathieu Lafage Dr. Hadrien Heuclin Dr. Xavier‐Frédéric Le Goff Dr. Nathalie Saffon‐Merceron Dr. Nicolas Mézailles 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):16995-17003
The synthesis of two novel titanium carbene complexes from the bis(thiophosphinoyl)methanediide geminal dianion 1 (SCS2?) is described. Dianion 1 reacts cleanly with 0.5 equivalents of [TiCl4(thf)2] to afford the bis‐carbene complex [(SCS)2Ti] ( 2 ) in 86 % yield. The mono‐carbene complex [(SCS)TiCl2(thf)] ( 3 ) can also be obtained by using an excess of [TiCl4(thf)2]. The structures of 2 and 3 are confirmed by X‐ray crystallography. A strong nucleophilic reactivity towards various electrophiles (ketones and aldehydes) is observed. The reaction of 3 with N,N′‐dicyclohexylcarbodiimide (DCC) and phenyl isocyanate leads to the formation of two novel diphosphinoketenimines 8 a and 8 b . The bis‐titanium guanidinate complex 9 is trapped as the by‐product of the reaction with DCC. The X‐ray crystal structures of 8 a and 9 are presented. The mechanism of the reaction between complex 3 and DCC is rationalized by DFT studies. 相似文献
18.
Jie‐Ying Wu Suchada Chantrapromma Dong‐Wen Chen Yu‐Peng Tian Ping Yang Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):523-525
The tetradentate N2S2 Schiff base ligand 3,3′‐[2,2′‐(ethylenedioxy)dibenzylidene]bis(S‐methyl dithiocarbazate) (H2L), prepared by the condensation of S‐methyl dithiocarbazate with 1,4‐bis(2‐formylphenyl)‐1,4‐dioxabutane in a 1:2 molar ratio, reacts with nickel acetate to form the title neutral metal complex, [Ni(C20H20N4O2S4)]. The X‐ray structure of the complex shows a distorted square‐planar geometry around the Ni atom. The monomeric units are weakly associated into dimers via a long Ni?S interaction [3.569 (1) Å]. These dimeric units are then linked by C—H?S intermolecular contacts to form a polymeric chain along the a axis. 相似文献
19.
Thomas Pautzsch Elisabeth Klemm 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):2911-2919
Poly{bis(4,4′‐tert‐butyl‐2,2′‐bipyridine)–(2,2′‐bipyridine‐5,5′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3a ), poly{bis(4,4′‐tert‐butyl‐2,2′‐bipyridine)–(2,2′‐bipyridine‐4,4′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3b ), and poly{bis(2,2′‐bipyridine)–(2,2′‐bipyridine‐5,5′‐diyl‐[1,4‐phenylene])–ruthenium(II)bishexafluorophosphate} ( 3c ) were synthesized by the Suzuki coupling reaction. The alternating structure of the copolymers was confirmed by 1H and 13C NMR and elemental analysis. The polymers showed, by ultraviolet–visible, the π–π* absorption of the polymer backbone (320–380 nm) and at a lower energy attributed to the d–π* metal‐to‐ligand charge‐transfer absorption (450 nm for linear 3a and 480 nm for angular 3b ). The polymers were characterized by a monomodal molecular weight distribution. The degree of polymerization was approximately 8 for polymer 3b and 28 for polymer 3d . © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2911–2919, 2004 相似文献
20.
《化学:亚洲杂志》2017,12(18):2494-2500
Donor–acceptor–donor (D–A–D)‐type thermally activated delayed fluorescence (TADF) emitters 5,5′‐bis{4‐[9,9‐dimethylacridin‐10(9H )‐yl]phenyl}‐2,2′‐bipyrimidine (Ac‐bpm) and 5,5′‐bis[4‐(10H ‐phenoxazin‐10‐yl)phenyl]‐2,2′‐bipyrimidine (Px‐bpm), based on the 2,2′‐bipyrimidine accepting unit, were developed and their TADF devices were fabricated. The orthogonal geometry between the donor unit and the 2,2′‐bipyrimidine accepting core facilitated a HOMO/LUMO spatial separation, thus realizing thermally activated delayed fluorescence. The exhibited electroluminescence ranged from green to yellow, depending on the donor unit, with maximum external quantum efficiencies of up to 17.1 %. 相似文献