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1.
1, 3, 4-Thiadiazol-2, 5-Dithiol als Komplexierungsreagenz. II. Komplexe des NiII, RhI, PdII, PtII, AuIII und CuII Complexes of NiII, RhI, PdII, PtII, AuIII, and CuII with 1, 3, 4-thiadiazole-2, 5- dithiol have been prepared. Probable structures have been proposed for the complexes on the basis of chemical analysis, magnetic susceptibility and spectral data. Crystal field parameters have been calculated which are in keeping with the structures proposed. 相似文献
2.
Dr. Manuel Alcarazo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(26):7868-7877
In coordination chemistry, typical ancillary ligands are anionic or neutral species. Cationic ones are exceptions and, when used, the positively charged groups are normally attached to the periphery and not close to the donating atom. However, this concept article highlights a series of recent experimental, as well as theoretical results, suggesting that the utility in catalysis of cationic phosphines with no spacer between the phosphorus atom and the positively charged group(s) has been largely overlooked. In fact, a growing number of studies indicate that, because of their specific architecture, these cationic ligands depict excellent π‐acceptor character that can exceed that of phosphites or polyfluorinated phosphines. This property has been used to increase the Lewis acidity of the metals they coordinate. Specifically, new extreme π‐acid catalysts, mainly based on PtII and AuI, have been recently prepared and their superior performance demonstrated along several mechanistically distinct transformations. In this concept article the current state of the art is critically assessed and possible future directions of the topic discussed. 相似文献
3.
Qingshu Zheng Stefan Borsley Gary S. Nichol Fernanda Duarte Scott L. Cockroft 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12747-12753
Metallophilic interactions are increasingly recognized as playing an important role in molecular assembly, catalysis, and bio‐imaging. However, present knowledge of these interactions is largely derived from solid‐state structures and gas‐phase computational studies rather than quantitative experimental measurements. Here, we have experimentally quantified the role of aurophilic (AuI???AuI), platinophilic (PtII???PtII), palladophilic (PdII???PdII), and nickelophilic (NiII???NiII) interactions in self‐association and ligand‐exchange processes. All of these metallophilic interactions were found to be too weak to be well‐expressed in several solvents. Computational energy decomposition analyses supported the experimental finding that metallophilic interactions are overall weak, meaning that favorable dispersion and orbital hybridization contributions from M???M binding are largely outcompeted by electrostatic or dispersion interactions involving ligand or solvent molecules. This combined experimental and computational study provides a general understanding of metallophilic interactions and indicates that great care must be taken to avoid over‐attributing the energetic significance of metallophilic interactions. 相似文献
4.
Unusual Metal–Metal Bonding in a Dinuclear Pt–Au Complex: Snapshot of a Transmetalation Process
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Dr. Miguel Baya Dr. Úrsula Belío Dr. Israel Fernández Dr. Sara Fuertes Dr. Antonio Martín 《Angewandte Chemie (International ed. in English)》2016,55(24):6978-6982
The dinuclear Pt–Au complex [(CNC)(PPh3)Pt Au(PPh3)](ClO4) ( 2 ) (CNC=2,6‐diphenylpyridinate) was prepared. Its crystal structure shows a rare metal–metal bonding situation, with very short Pt–Au and Au–Cipso(CNC) distances and dissimilar Pt–Cipso(CNC) bonds. Multinuclear NMR spectra of 2 show the persistence of the Pt–Au bond in solution and the occurrence of unusual fluxional behavior involving the [PtII] and [AuI] metal fragments. The [PtII]??? [AuI] interaction has been thoroughly studied by means of DFT calculations. The observed bonding situation in 2 can be regarded as a model for an intermediate in a transmetalation process. 相似文献
5.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(44):14049-14053
The synthesis and characterization of hitherto hypothetical AuIII π‐alkyne complexes is reported. Bonding and stability depend strongly on the trans effect and steric factors. Bonding characteristics shed light on the reasons for the very different stabilities between the classical alkyne complexes of PtII and their drastically more reactive AuIII congeners. Lack of back‐bonding facilitates alkyne slippage, which is energetically less costly for gold than for platinum and explains the propensity of gold to facilitate C−C bond formation. Cycloaddition followed by aryl migration and reductive deprotonation is presented as a new reaction sequence in gold chemistry. 相似文献
6.
Dr. Yuri Tulchinsky Dr. Sebastian Kozuch Dr. Prasenjit Saha Assaf Mauda Dr. Gennady Nisnevich Dr. Mark Botoshansky Dr. Linda J. W. Shimon Prof. Mark Gandelman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7099-7110
Comprehensive studies on the coordination properties of tridentate nitrenium‐based ligands are presented. N‐heterocyclic nitrenium ions demonstrate general and versatile binding abilities to various transition metals, as exemplified by the synthesis and characterization of RhI, RhIII, Mo0, Ru0, RuII, PdII, PtII, PtIV, and AgI complexes based on these unusual ligands. Formation of nitrenium–metal bonds is unambiguously confirmed both in solution by selective 15N‐labeling experiments and in the solid state by X‐ray crystallography. The generality of N‐heterocyclic nitrenium as a ligand is also validated by a systematic DFT study of its affinity towards all second‐row transition and post‐transition metals (Y–Cd) in terms of the corresponding bond‐dissociation energies. 相似文献
7.
Akito Nakai Shin‐ichiro Ishida Takanori Soya Atsuhiro Osuka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(24):8281-8284
Ruthenium(II) π‐coordination onto [28]hexaphyrins(1.1.1.1.1.1) has been accomplished. Reactions of bis‐AuIII and mono‐AuIII complexes of hexakis(pentafluorophenyl) [28]hexaphyrin with [RuCl2(p‐cymene)]2 in the presence of NaOAc gave the corresponding π‐ruthenium complexes, in which the [(p‐cymene)Ru]II fragment sat on the deprotonated side pyrrole. A similar reaction of the bis‐PdII [26]hexaphyrin complex afforded a triple‐decker complex, in which the two [(p‐cymene)Ru]II fragments sat on both sides of the center of the [26]hexaphyrin framework. 相似文献
8.
Alexander S. Novikov Dr. Maxim L. Kuznetsov Prof. Armando J. L. Pombeiro 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(8):2874-2888
The theoretical background of the formation of N‐heterocyclic oxadiazoline carbenes through a metal‐assisted [2+3]‐dipolar cycloaddition (CA) reaction of nitrones R1CH?N(R2)O to isocyanides C?NR and the decomposition of these carbenes to imines R1CH?NR2 and isocyanates O?C?NR is discussed. Furthermore, the reaction mechanisms and factors that govern these processes are analyzed in detail. In the absence of a metal, oxadiazoline carbenes should not be accessible due to the high activation energy of their formation and their low thermodynamic stability. The most efficient promotors that could assist the synthesis of these species should be “carbenophilic” metals that form a strong bond with the oxadiazoline heterocycle, but without significant involvement of π‐back donation, namely, AuI, AuIII, PtII, PtIV, ReV, and PdII metal centers. These metals, on the one hand, significantly facilitate the coupling of nitrones with isocyanides and, on the other hand, stabilize the derived carbene heterocycles toward decomposition. The energy of the LUMOCNR and the charge on the N atom of the C?N group are principal factors that control the cycloaddition of nitrones to isocyanides. The alkyl‐substituted nitrones and isocyanides are predicted to be more active in the CA reaction than the aryl‐substituted species, and the N,N,C‐alkyloxadiazolines are more stable toward decomposition relative to the aryl derivatives. 相似文献
9.
F. Mark Chadwick Basile F. E. Curchod Rosario Scopelliti Farzaneh FadaeiTirani Euro Solari Kay Severin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(6):1778-1781
Azoimidazolium dyes were used as precursors for mesoionic carbene ligands (Azo‐MICs). The properties of these ligands were examined by synthesizing RhI, AuI, and PdII complexes. Experimental (NMR, IR) and theoretical investigations show that Azo‐MICs are potent σ‐donor ligands. Yet, they feature a small singlet–triplet gap and very low‐lying LUMO levels. The unique electronic properties of Azo‐MICs allow for reversible one‐electron reductions of the metal complexes, as evidenced by cyclic voltammetry. 相似文献
10.
The first examples of late transition metal η5-arsolyls (L = CO, P(OMe)3; R = Ph, Me, Et, SiMe3; R′ = Ph, H, Me, Et, Me) serve as ditopic donors to extraneous metal centres (M = PtII, AuI, HgII) through both conventional As → M and polar-covalent (dative) Co → M interactions.Cobalt carbonyl reacts with arsoles to provide the first late transition metal η5-arsolyls. These serve as ditopic donors to extraneous metal centres (M = PtII, AuI, HgII) through both conventional AsM and polar-covalent (dative) CoM interactions. 相似文献
11.
Control over the Self‐Assembly Modes of PtII Complexes by Alkyl Chain Variation: From Slipped to Parallel π‐Stacks
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Dr. Naveen Kumar Allampally Dr. María José Mayoral Dr. Sarayute Chansai Dr. María Cristina Lagunas Prof. Christopher Hardacre Dr. Vladimir Stepanenko Prof. Rodrigo Q. Albuquerque Prof. Dr. Gustavo Fernández 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7810-7816
We report the self‐assembly of a new family of hydrophobic, bis(pyridyl) PtII complexes featuring an extended oligophenyleneethynylene‐derived π‐surface appended with six long (dodecyloxy ( 2 )) or short (methoxy ( 3 )) side groups. Complex 2 , containing dodecyloxy chains, forms fibrous assemblies with a slipped arrangement of the monomer units (dPt???Pt≈14 Å) in both nonpolar solvents and the solid state. Dispersion‐corrected PM6 calculations suggest that this organization is driven by cooperative π–π, C?H???Cl and π–Pt interactions, which is supported by EXAFS and 2D NMR spectroscopic analysis. In contrast, nearly parallel π‐stacks (dPt???Pt≈4.4 Å) stabilized by multiple π–π and C?H???Cl contacts are obtained in the crystalline state for 3 lacking long side chains, as shown by X‐ray analysis and PM6 calculations. Our results reveal not only the key role of alkyl chain length in controlling self‐assembly modes but also show the relevance of Pt‐bound chlorine ligands as new supramolecular synthons. 相似文献
12.
Dr. Israel Fernández Prof. Dr. Fernando P. Cossío Dr. Abel de Cózar Prof. Dr. Agustí Lledós Prof. Dr. José Luis Mascareñas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(40):12147-12157
The thermal [4+3] cycloaddition reaction between allenes and tethered dienes (1,3‐butadiene and furan) assisted by transition metals (AuI, AuIII, PdII, and PtII) was studied computationally within the density functional theory framework and compared to the analogous non‐organometallic process in terms of activation barriers, synchronicity and aromaticity of the corresponding transition states. It was found that the metal‐mediated cycloaddition reaction is concerted and takes place via transition structures that can be even more synchronous and more aromatic than their non‐organometallic analogues. However, the processes exhibit slightly to moderately higher activation barriers than the parent cycloaddition involving the hydroxyallylic cation. The bond polarization induced by the metal moiety is clearly related to the interaction of the transition metal with the allylic π* molecular orbital, which constitutes the LUMO of the initial reactant. Finally, replacement of the 1,3‐butadiene by furan caused the transformation to occur stepwise in both the non‐organometallic and metal‐assisted processes. 相似文献
13.
A Tray‐Shaped,PdII‐Clipped Au3 Complex as a Scaffold for the Modular Assembly of [3×n] Au Ion Clusters
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Takafumi Osuga Dr. Takashi Murase Dr. Manabu Hoshino Prof. Dr. Makoto Fujita 《Angewandte Chemie (International ed. in English)》2014,53(42):11186-11189
A tray‐shaped PdII3AuI3 complex ( 1 ) is prepared from 3,5‐bis(3‐pyridyl)pyrazole by means of tricyclization with AuI followed by PdII clipping. Tray 1 is an efficient scaffold for the modular assembly of [3×n] AuI clusters. Treatment of 1 with the AuI3 tricyclic guest 2 in H2O/CH3CN (7:3) or H2O results in the selective formation of a [3×2] cluster ( 1 ? 2 ) or a [3×3] cluster ( 1 ? 2 ? 1 ), respectively. Upon subsequent addition of AgI ions, these complexes are converted to an unprecedented Au3–Au3–Ag–Au3–Au3 metal ion cluster. 相似文献
14.
Takafumi Osuga Takashi Murase Manabu Hoshino Makoto Fujita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(42):11368-11371
A tray‐shaped PdII3AuI3 complex ( 1 ) is prepared from 3,5‐bis(3‐pyridyl)pyrazole by means of tricyclization with AuI followed by PdII clipping. Tray 1 is an efficient scaffold for the modular assembly of [3×n] AuI clusters. Treatment of 1 with the AuI3 tricyclic guest 2 in H2O/CH3CN (7:3) or H2O results in the selective formation of a [3×2] cluster ( 1 ⋅ 2 ) or a [3×3] cluster ( 1 ⋅ 2 ⋅ 1 ), respectively. Upon subsequent addition of AgI ions, these complexes are converted to an unprecedented Au3–Au3–Ag–Au3–Au3 metal ion cluster. 相似文献
15.
Planar 2‐Pyridyl‐1,2,3‐triazole Derived Metallo‐ligands: Self‐assembly with PdCl2 and Photocatalysis
Natalie R. Lagesse Kelvin Y. L. Tan James D. Crowley James A. Findlay 《化学:亚洲杂志》2020,15(10):1567-1573
Self‐assembled metallosupramolecular architectures (MSAs) with built‐in functionalities such as light‐harvesting metal centers are a promising approach for developing emergent properties within discrete molecular systems. Herein we describe the synthesis of two new but simple “click” ligands featuring a bidentate 2‐pyridyl‐1,2,3‐triazole chelate pocket linked to a monodentate pyridyl (either 3‐ or 4‐substituted, L1 and L2 ) unit. The ligands and the corresponding four PdIIand PtIImetallo‐ligands ( Pd1 , Pd2 , Pt1 and Pt2 ) were synthesized and characterized using nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI‐MS), and X‐ray crystallography. Solid‐state characterization of the series of ligands and metallo‐ligands revealed that these compounds display a co‐planar conformation of all the aryl units. The PtIIcontaining metallo‐ligands ( Pt1 and Pt2 ) were found to assemble into square ( Sqr ) and triangular ( Tri ) shaped architectures when combined with neutral PdCl2 linker units. Additionally, the ability of the PtIImetallo‐ligands and Tri to photocatalyze the cycloaddition of singlet oxygen to anthracene was investigated. 相似文献
16.
Jessica Rodriguez Gyrgy Szalki E. Daiann Sosa Carrizo Nathalie Saffon‐Merceron Karinne Miqueu Didier Bourissou 《Angewandte Chemie (International ed. in English)》2020,59(4):1511-1515
Gold(III) π‐complexes have been authenticated recently with alkenes, alkynes, and arenes. The key importance of PdII π‐allyl complexes in organometallic chemistry (Tsuji–Trost reaction) prompted us to explore gold(III) π‐allyl complexes, which have remained elusive so far. The (P,C)AuIII(allyl) and (methallyl) complexes 3 and 3′ were readily prepared and isolated as thermally and air‐stable solids. Spectroscopic and crystallographic analyses combined with detailed DFT calculations support tight quasi‐symmetric η3‐coordination of the allyl moiety. The π‐allyl gold(III) complexes are activated towards nucleophilic additions, as substantiated with β‐diketo enolates. 相似文献
17.
Federica Guarra Alessio Terenzi Christine Pirker Rossana Passannante Dina Baier Ennio Zangrando Vanessa Gmez‐Vallejo Tarita Biver Chiara Gabbiani Walter Berger Jordi Llop Luca Salassa 《Angewandte Chemie (International ed. in English)》2020,59(39):17130-17136
AuIII complexes with N‐heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII‐NHC complexes by direct oxidation with radioactive [124I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII‐to‐AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII‐NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation. 相似文献
18.
Philipp von Grebe Dr. Pablo J. Sanz Miguel Prof. Dr. Bernhard Lippert 《无机化学与普通化学杂志》2012,638(11):1691-1698
Acid‐base and ligating properties of three bis(substituted)pyrazine (pz) and pyrimidine (pym) ligands (pyrazine‐2, 5‐dicarboxylic acid, 2, 5‐pzdcH2, 2, 3‐bis(pyridine‐2‐yl)pyrazine, 2, 3‐bppz, pyrimidine‐4, 6‐dicarboxylic acid, 4, 6‐pmdcH2) toward cis‐PtIIa2 (a = NH3, a2 = en, a2 = 2, 2′‐bpy) have been studied. Combinations of pz‐N/pym‐N with donor atoms of the substituents lead to 5‐membered platinum chelates, but exclusive N, N‐coordination through the pyridyl substituents of 2, 3‐bppz can lead to a 7‐membered platinum chelate with a characteristic L‐shape of the resulting cation. It is observed for PtII(2, 2′‐bpy), yet not for PtII(en), and is a consequence of differences in sterical interactions between the 2, 3‐bppz ligand and the coligands of PtII. 相似文献
19.
A. I. Kokorin M. V. Evstiferov I. A. Grigor'ev V. A. Reznikov G. Grampp 《Russian Chemical Bulletin》1999,48(10):1982-1986
The characteristic features of intramolecular spin exchange in 14 complexes of AgI, HgII, NiII, PdII, PtII, AuIII, and PtIV with spin-labeled ligands were studied by ESR spectroscopy. The measured values of the exchange integral ‖J‖ and the differences between the enthalpies of the efficient conformations (ΔH) were compared with the electronic polarization (refraction)R
f of the NiII, PdII, and PtII ions and Klopman's rigidity parameters σK, which characterize the total polarazibility of the ions and the degree of covalence of the bond between the metal atom and
the donor atom of the ligand, respectively. Delocalization of the electron spin density and the efficiency of spin exchange
are determined by the relative contributions of the s, p, and d orbitals, which produce the overlap integral of wave functions,
‖J‖, and by the geometric features of the coordination polyhedron, which affect the mutual orientation of the N−O fragments.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2005–2009, October, 1999. 相似文献
20.
Johannes Karges Thirumal Yempala Mickaël Tharaud Dan Gibson Gilles Gasser 《Angewandte Chemie (International ed. in English)》2020,59(18):7069-7075
PtII complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, PtIV complexes are being developed as prodrug candidates that are activated by reduction in cancer cells. Concomitantly, RuII polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel PtIV–RuII conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the PtIV centre is reduced to PtII and the axial ligands including the RuII complex and phenylbutyrate are released. As each component has its individual targets, the conjugate exerts a multi‐target and multi‐action effect with (photo‐)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids. 相似文献