- Noble Metal Corrosion: Halogen Bonded Iodocarbenium Iodides Dissolve Elemental Gold—Direct Access to Gold–Carbene Complexes
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A common method to dissolve elemental gold involves the combination of an oxidant with a Lewis base that coordinates to the gold surface, thus lowering the metal's redox potential. Herein we report the usage of organic iodide salts, which provide both oxidative power and a coordinating ligand, to dissolve gold under formation of organo-gold complexes. The obtained products were identified as AuIII complexes, all featuring Au?C bonds, as shown by X-ray single-crystal analysis, and can be isolated in good yields. Additionally, our method provides direct access to N-heterocyclic carbene (NHC-type) complexes and avoids costly organometallic precursors. The investigated complexes show dynamic behavior in acetonitrile and in the case of the NHC(-type) complexes, the involved species could be identified as a monocarbene [AuI3(carbene)] and biscarbene complex [AuI2(carbene)2]+.
- Holthoff, Jana M.,Engelage, Elric,Kowsari, Alexander B.,Huber, Stefan M.,Weiss, Robert
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- NMR Quantification of Halogen-Bonding Ability to Evaluate Catalyst Activity
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Quantification of halogen-bonding abilities is described for a series of benzimidazolium-, imidazolium- and bis(imidazolium) halogen-bond donors (XBDs) using 31P NMR spectroscopy. The measured Δδ(31P) values correlate with calculated activation free energ
- Chang, Yun-Pu,Tang, Teresa,Jagannathan, Jake R.,Hirbawi, Nadia,Sun, Shaoming,Brown, Jonah,Franz, Annaliese K.
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supporting information
p. 6647 - 6652
(2020/09/09)
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- Zinc-Ion-Stabilized Charge-Transfer Interactions Drive Self-Complementary or Complementary Molecular Recognition
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Here, we show that charge-transfer interactions determine whether donor and acceptor ditopic ligands will associate in a complementary or self-complementary fashion upon metal-ion clipping. Anthracene-based (9,10LD and 1,5LD) and anthraquinone-based (1,5LA) ditopic ligands containing two imidazole side arms as zinc coordination sites were designed. The 9,10LD and 1,5LA systems associated in a complementary fashion (LA/LD/LA) upon clipping by two zinc ions (Zn2+) to form an alternating donor-acceptor assembly [(9,10LD)(1,5LA)2-(Zn2+)2]. However, once the charge-transfer interactions were perturbed by subtle modifications of the imidazole side arms (9,10LD′(S) and 1,5LA′(S)), self-complementary association (LD′/LD′/LD′/LD′ and LA′/LA′/LA′/LA′) between the donor (9,10LD′(S)) and acceptor (1,5LA′(S)) ligands predominantly occurred to form homoassemblies [(9,10LD′(S))4-(Zn2+)2 and (1,5LA′(S))4-(Zn2+)2]. As in the case of a homochiral pair (9,10LD′(S) and 1,5LA′(S)), self-complementary association (narcissistic self-sorting) occurred in the Zn2+ assembly with heterochiral combinations of the donor and acceptor ligands (9,10LD′(S)/1,5LA′(R) and 9,10LD′(S)/1,5LA′(R)/1,5LA′(R)). Narcissistic self-sorting also took place between the positional isomer of the donor ligands (9,10LD and 1,5LD) to form individual homoligand assemblies [(9,10LD)4-(Zn2+)2 and (1,5LD)4-(Zn2+)2]. Conversely, statistical association took place in the Zn2L4 assembly process of an isomorphous pair of the donor and acceptor ligands (1,5LD and 1,5LA).
- Iseki, Shuta,Kishida, Sakura,Nonomura, Kohei,Ogata, Daiji,Yuasa, Junpei
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supporting information
p. 15842 - 15851
(2020/10/18)
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- Dynamic Open Coordination Cage from Nonsymmetrical Imidazole–Pyridine Ditopic Ligands for Turn-On/Off Anion Binding
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This work demonstrates a new nonconventional ligand design, imidazole/pyridine-based nonsymmetrical ditopic ligands (1 and 1S), to construct a dynamic open coordination cage from nonsymmetrical building blocks. Upon complex formation with Pd2+ at a 1:4 molar ratio, 1 and 1S initially form mononuclear PdL4 complexes (Pd2+(1)4 and Pd2+(1S)4) without formation of a cage. The PdL4 complexes undergo a stoichiometrically controlled structural transition to Pd2L4 open cages ((Pd2+)2(1)4 and (Pd2+)2(1S)4) capable of anion binding, leading to turn-on anion binding. The structural transitions between the Pd2L4 open cage and the PdL4 complex are reversible. Thus, stoichiometric addition (2 equiv) of free 1S to the (Pd2+)2(1S)4 open cage holding a guest anion ((Pd2+)2(1S)4?G?) enables the structural transition to the Pd2+(1S)4 complex, which does not have a cage and thus causes the release of the guest anion (Pd2+(1S)4+G?).
- Ogata, Daiji,Yuasa, Junpei
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supporting information
p. 18424 - 18428
(2019/11/22)
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- Palladium(ii) N-heterocyclic allenylidene complexes with extended intercationic Pd?Pd interactions and MMLCT phosphorescence
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Extended intercationic Pd?Pd contacts of 3.30 ? in the crystal structure and distinct MMLCT transitions absorbing at 528 nm and emitting beyond 600 nm in solutions have been revealed with cyclometalated Pd(ii) N-heterocyclic allenylidene complexes. The Pd
- Zou, Chao,Lin, Jinqiang,Suo, Sa,Xie, Mo,Chang, Xiaoyong,Lu, Wei
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supporting information
p. 5319 - 5322
(2018/06/01)
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- T -BuONa-mediated direct C-H halogenation of electron-deficient (hetero)arenes
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An efficient halogenation of electron-deficient (hetero)arenes is described. The reaction utilizes common t-BuONa as a catalyst (for iodination) or a promoter (for bromination and chlorination), and perfluorobutyl iodide, CBr4 or CCl4 as the readily-available halogenating agents, respectively. The protocol features broad scope, high efficiency, mild conditions and gram scalability. An ionic pathway involving halogen bond formation and halophilic attack is proposed. The utility of the resulting iodinated heteroarenes is demonstrated in visible light-mediated Caryl-Caryl cross-coupling reaction.
- Liu, Xia,Zhao, Xin,Liang, Fushun,Ren, Baoyi
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supporting information
p. 886 - 890
(2018/02/19)
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- Synthesis of Complexes with Protic NH,NR-NHC Ligands by Oxidative Addition of N-Alkyl-2-iodoimidazoles to [M(PPh3)4] (M = Pd, Pt) Complexes
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The oxidative addition of N-methyl-2-iodoimidazole (1) or N-benzyl-2-iodoimidazole (2) to complexes [Pd(PPh3)4] or [Pt(PPh3)4] followed by the protonation of the unsubstituted imidazolato ring nitrogen atom yielded complexes trans-[M(NH,NMe-NHC)(PPh3)2I]PF6 (M = Pd: trans-[3]PF6; M = Pt: trans-[4]PF6) and trans-[M(NH,NBz-NHC)(PPh3)2I]PF6 (M = Pd: trans-[5]PF6; M = Pt: trans-[6]PF6) bearing imidazole-derived protic NH,NR-NHC (pNHC) ligands. In the absence of a proton source, the reaction of 1 with [Pd(PPh3)4] yielded the dinuclear dipalladium complex [7] featuring bridging imidazolato ligands metalated at the C2 ring-carbon atom and the N3 ring-nitrogen atom. Palladium complex trans-[3]PF6 undergoes halogen abstraction with AgPF6 to give acetonitrile complex trans-[Pd(NCCH3)(NH,NMe-NHC)(PPh3)2](PF6)2 trans-[8](PF6)2. This complex reacts further with 1,10-phenanthroline (phen), affording complex [Pd(NH,NMe-NHC)(PPh3)(phen)](PF6)2 [9](PF6)2.
- Jin, Hanpeng,Kluth, Peter,Hahn, F. Ekkehardt
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p. 2774 - 2781
(2017/06/06)
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- Method for preparing halogenated (hetero) aromatic hydrocarbons
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The invention relates to a method for preparing halogenated (hetero) aromatic hydrocarbons. The halogenated (hetero) aromatic hydrocarbons are prepared from cheap and easily available perfluorobutyl iodide, carbon tetrabromide and carbon tetrachloride as iodinated, brominated and chlorinated reagents respectively under the action of alkali catalysis (promotion). The method comprises the following steps: firstly, (hetero) aromatic hydrocarbons, a halogenated reagent and an inorganic base are placed in an organic solvent, stirred at room temperature and monitored with TLC until a substrate disappears, and the reaction is stopped; then, a reaction mixed solution is poured into water and extracted, an organic phase is dried, and the organic solvent is removed under reduced pressure; finally, silica-gel column chromatography is performed on a crude product, and a product is obtained. Purification can also be performed by recrystallization. The method has the advantages that the synthetic route is wide in substrate range, raw materials and reagents are cheap and easily available, operation is simple, conditions are mild, yield is high, energy consumption is reduced, the reaction route is safe, gram-grade preparation can be performed and the like.
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Paragraph 0039; 0040
(2018/03/24)
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- Zwitterionic-Type Molten Salt Catalyzed Iodination in Water: Synthesis of Iodoimidazoheterocycles
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An environmentally benign protocol for the iodination of imidazoheterocycles has been developed through sp2 C-H bond functionalization with molecular iodine in water at room temperature. The reaction is catalyzed by an imidazole-based zwitterio
- Mondal, Susmita,Samanta, Sadhanendu,Singsardar, Mukta,Mishra, Subhajit,Mitra, Shubhanjan,Hajra, Alakananda
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supporting information
p. 4009 - 4015
(2016/11/11)
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- Homoleptic gold(i) N-heterocyclic allenylidene complexes: Excited-state properties and lyotropic chromonics
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A series of phosphorescent Au(i) bis(N-heterocyclic allenylidene) complexes, namely [Au(=C=C=CR1R2)2]+X-, were synthesized and structurally characterized. These organometallic complexes exhibit panchromatic transient absorption upon electronic photo-excitation and can self-organize into lyotropic chromonic mesophases in aqueous solutions.
- Xiao, Xin-Shan,Zou, Chao,Guan, Xiangguo,Yang, Chen,Lu, Wei,Che, Chi-Ming
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supporting information
p. 4983 - 4986
(2016/04/06)
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- Halogen-bonding-induced hydrogen transfer to C=N bond with hantzsch ester
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Several bidentate dihydroimidazolines were prepared and investigated as catalysts for hydrogen transfer reduction of C=N bond with Hantzsch ester. Highly efficient reactions were observed for quinolines and imines with low catalyst loading of 2 mol %. The presence of halogen bonding was elucidated using NMR studies and isothermal calorimeric titrations. Binding constants of the XB donors were also measured using isothermal calorimeric titrations (ITC).
- He, Wei,Ge, Yi-Cen,Tan, Choon-Hong
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supporting information
p. 3244 - 3247
(2014/07/08)
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- Battlement-shaped 1D coordination polymer based on a bis(N-methylimidazole- 2-yl)butadiyne ligand
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Bis(N-methylimidazole-2-yl)butadiyne (bmib) has been prepared starting from N-methylimidazole following two different pathways. Bmib fluoresces and is capable of forming 1D coordination polymers by clamping together metal units. The molecular structure of a zinc coordination polymer based on bmib and zinc acetate resembles a battlement of a fortress.
- Waidmann, Thomas,Fritsch, Nico,Tucher, Johannes,Rudolf, Marc,Glaser, Felix,Guldi, Dirk M.,Burzlaff, Nicolai
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p. 10157 - 10160
(2013/12/04)
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- A new, mild one-pot synthesis of iodinated heterocycles as suitable precursors for N-heterocyclic carbene complexes
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The use of I2/AgOAc in dichloromethane constitutes a cheap, mild, and efficient method for the selective iodination of a variety of heterocycles. In a number of cases, this method provides superior yields to other literature methods and affords iodo-functionalized heterocycles that are suitable precursors for carbene complexes.
- Iglesias, Manuel,Schuster, Oliver,Albrecht, Martin
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experimental part
p. 5423 - 5425
(2010/11/02)
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- Substituted propiolic acid amides and their use for producing drugs
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The present invention relates to substituted propiolic acid amides, methods for the production thereof, medicaments containing these compounds and the use thereof for producing medicaments.
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Page/Page column 45
(2008/12/04)
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- Supramolecular array of imizazolylethynyl-zinc-porphyrin
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Novel imidazolylethynyl-zinc-porphyrin 1a and its meso,meso-linked bisporphyrin 5M were synthesized effectively by the reaction of the corresponding bromoporphyrins and 2-imidazolylethyne in the presence of palladium-arsenic catalyst. The complementary coordination of monomer 1a into dimer 2a was observed by 1H NMR and UV-Vis spectroscopy. Self-association constant of 1a to 2a in CHCl3 (including 0.5% ethanol) was determined as 1.84 × 107 M-1 by UV-Vis titration of 2a with N-methylimidazole. UV-Vis absorption and fluorescence spectra of 1a, 2a, monomer 5M, and its polymer 5P were compared.
- Satake, Akiharu,Shoji, Osami,Kobuke, Yoshiaki
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p. 635 - 644
(2008/02/06)
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- Recyclable Sonogashira coupling reactions in an ionic liquid, effected in the absence of both a copper salt and a phosphine
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(Bisimidazole)Pd(Me)Cl catalyzes an efficient and recyclable Sonogashira coupling reaction without copper salts or bulky phosphine ligands, in an ionic liquid.
- Park, Soon Bong,Alper, Howard
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p. 1306 - 1307
(2007/10/03)
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- Highly efficient, recyclable Pd(II) catalysts with bisimidazole ligands for the heck reaction in ionic liquids
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(Matrix presented) New Pd(II) complexes with bisimidazole ligands were prepared and proved to be effective catalysts for the Heck reaction under phosphine-free conditions using ionic liquids as solvents. This system could be recycled five times without any loss of catalytic activity.
- Park, Soon Bong,Alper, Howard
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p. 3209 - 3212
(2007/10/03)
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- 4,4-(disubstituted) cyclohexan-1-one monomers and related compounds
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This invention relates to derivatives of 4,4-(disubstituted)cyclohexan-1-ones and related compounds which are useful for treating allergic and inflammatory diseases.
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- Preparation and reactions of new zincated nitrogen-containing heterocycles
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A range of nitrogen-containing iodinated or in some cases brominated heterocycles were converted to the corresponding zincated heterocyclic derivatives by the direct insertion of zinc dust under mild conditions (25°C to 70°C, 1-3 h) in a solvent like THF or DMAC. This reaction was extended to the preparation of zincated nucleic acid bases and nucleosides. The reaction of these new zinc reagents toward various electrophiles with palladium (O) or copper(I) catalysis allows the preparation of a broad range of polyfunctional nitrogen-containing heterocycles.
- Prasad, A. S. Bhanu,Stevenson, Thomas M.,Citineni, Janakiram Rao,Nyzam, Valerie,Knochel, Paul
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p. 7237 - 7254
(2007/10/03)
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