Coordination chemistry and catalysis with hemilabile oxygen-phosphorus ligands

Bader, Armin; Lindner, Ekkehard

doi:10.1016/0010-8545(91)80013-4

Cited by 804 publications

(341 citation statements)

References 199 publications

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“…Several classes of complexes of different metals and hemilabile ligands with a number of different scaffolds, different pivots and labile donors were synthesized and recently reviewed [2,3]. Furthermore, after the seminal article by Arduengo [4] a novel class of the performing donor ligands NHC was available for the chemists' community and hence several new heteroditopic and hemilabile NHC-E (E = P, N, O) ligands soon appeared in the literature [5].…”

Section: Introductionmentioning

confidence: 99%

The interaction between heteroditopic pyridine–nitrogen NHC with novel sulfur NHC ligands in palladium(0) derivatives: Synthesis and structural characterization of a bis-carbene palladium(0) olefin complex and formation in solution of an alkene–alkyne mixed intermediate as a consequence of the ligands hemilability

Canovese

Visentin

Levi

et al. 2012

Inorganica Chimica Acta

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited.In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit:http://www.elsevier.com/copyright

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Section: Introductionmentioning

confidence: 99%

The interaction between heteroditopic pyridine–nitrogen NHC with novel sulfur NHC ligands in palladium(0) derivatives: Synthesis and structural characterization of a bis-carbene palladium(0) olefin complex and formation in solution of an alkene–alkyne mixed intermediate as a consequence of the ligands hemilability

Canovese

Visentin

Levi

et al. 2012

Inorganica Chimica Acta

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“…Our group has introduced and focused on developing one of these strategies, which is referred to as the Weak-Link Approach (Scheme 1). This strategy allows one to prepare bimetallic macrocycles from simple transition metal and ligand precursors (7)(8)(9)(10)(11)(12), and it is based on reactions between flexible symmetrical hemilable ligands (13)(14)(15)(16) and transition metal precursors. Typically, macrocyclic intermediates that contain both strong (S-M) and weak (W-M) ligand-metal bonds (Scheme 1) are initially formed in very high and usually quantitative yield.…”

mentioning

confidence: 99%

Threefold symmetric trimetallic macrocycles formed via the Weak-Link Approach

Ovchinnikov

Holliday

Mirkin

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The synthesis and characterization of a new threefold symmetric hemilabile phosphino-alkylthioether ligand are described. This ligand can be used in combination with Rh(I) and Ir(I) precursor complexes to prepare 40-membered macrocyles with threefold symmetry via the Weak-Link Approach. Synthesis and characterization of two such structures are reported along with a single crystal x-ray diffraction analysis of one of the key intermediates in the case of Rh(I). This is a demonstration of the viability of the Weak-Link Approach for preparing structures other than bimetallic macrocycles and suggests that it could be generalized for a wide range of higher symmetry structures through appropriate hemilabile ligand design. R ecent developments in the field of supramolecular chemistry have resulted in the establishment of several new synthetic strategies for forming multimetallic macrocyclic architectures (1-6). Our group has introduced and focused on developing one of these strategies, which is referred to as the Weak-Link Approach (Scheme 1). This strategy allows one to prepare bimetallic macrocycles from simple transition metal and ligand precursors (7-12), and it is based on reactions between flexible symmetrical hemilable ligands (13-16) and transition metal precursors. Typically, macrocyclic intermediates that contain both strong (S-M) and weak (W-M) ligand-metal bonds (Scheme 1) are initially formed in very high and usually quantitative yield. For the systems studied thus far, ligands that consist of flexible phosphinoalkyl ether (7), thioether (12), or amino (11) bidentate ligand functionalities connected with rigid aromatic spacers (R) have been used. Once condensed, macrocyclic intermediates are formed, the weak ligand-metal bonds in these intermediates can be cleaved by means of simple ligand substitution reactions to afford open macrocyclic ring structures. Alternatively, both condensed and opened macrocycles can be used to construct more complex three-dimensional architectures such as cylinders (8) and trilayer metallocyclophanes (9).Although the generality of the weak-link methodology has been demonstrated with respect to twofold symmetric hemilabile ligands and transition metals, the application of this synthetic approach to the preparation of macrocyclic structures with more than two metals has not been demonstrated. Herein, we report the first application of the Weak-Link Approach to the formation of trimetallic (17-20) rhodium and iridium macrocycles from a flexible threefold symmetric hemilabile ligand. Methods and MaterialsGeneral Procedures. All reactions were performed under a nitrogen atmosphere in reagent grade solvents by using standard Schlenk or dry-box techniques (21). All other solvents were purified by published methods (22,23). Chemicals were purchased from Aldrich, unless otherwise mentioned, or prepared by literature methods, as referenced below.

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“…The (ether) oxygen atom can easily be displaced by an incoming substrate such as diamine [1,2,7,8]. Thus, ether-phosphines are capable of making available and protecting vacant coordination sites which lead to an improvement in both stability and catalytic activity of the organometallic species [7,8]. The title complex is crystallized as free solvated trans-dichlorocis-phosphine isomers with approximate C 2 symmetry.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of trans-dichloro-1,3-propanediamine-bis[(2-methoxyethyl) diphenylphosphine]ruthenium(II), RuCl2(C3H10N2)(C15H17OP)2

Warad

Al‐Resayes

Eichele

2006

Zeitschrift Für Kristallographie - New Crystal Structures

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C 33 H 44 Cl 2 N 2 O 2 P 2 Ru, monoclinic, P12 1 /c1 (no. 14), a = 13.278 (1) Source of materialAll the reactions were performed using Schlenk-type flask under argon and standard high vacuum-line techniques. Solvents were of analytical grade and distilled under argon. The title compound was synthesized by treating RuCl 2(h 2 -Ph2PCH2CH2OCH3)2 complex with slightly excess 1.3-propanediamine ligand in dichloromethane as described previously [1]. The crystals were grown by slow diffusion of diethyl ether into a solution of the complex in dichloromethane. They were re-crystallized from these two solutions. The desired complex was characterized by NMR, IR, and FAB-mass spectroscopy in addition to the elemental analysis [1,2]. DiscussionNowadays, due to economical and environmental inciting, increasing attention is dedicated to catalysts and reagents [3,4]. An attractive strategy to consist in the homogenous catalysts by using dichloro(phosphine)diamineruthenium complexes in field of hydrogenation has been recently constructed [3][4][5][6]. The two hemilabile bidentate ether-phosphine ligands were coordinated the ruthenium(II) center atom via phosphor and oxygen atoms. The (ether) oxygen atom can easily be displaced by an incoming substrate such as diamine [1,2,7,8]. Thus, ether-phosphines are capable of making available and protecting vacant coordination sites which lead to an improvement in both stability and catalytic activity of the organometallic species [7,8]. The title complex is crystallized as free solvated trans-dichlorocis-phosphine isomers with approximate C 2 symmetry. The ruthenium atom is coordinated two chlorine species in trans form, one diamine co-ligand via the nitrogen atoms and two (2-methoxyethyl)(diphenyl)-phosphine ligands via the phosphorus atoms in cis forms. The complex exhibits mostly regular octahedron geometry around the ruthenium center atom with two RuN distances of 2.1993 Å and 2.1932 Å, two RuCl distances of 2.4177 Å and 2.4244 Å and two RuP distances equal 2.2963 Å and 2.2910 Å. The diamine and ether-phosphine ligands are practically planar. (Deviations from the least-squares planes do not exceed 0.1 Å.) The coordination angle of the diamine chelate ring results in distinctly NRuN angles of 84.71°departs from ideal value by up to approximately 5.3 Å, due to the six-membered ring chelating nature of 1,3-propanediamine ligand, while the PRuP angle is equal 91.17°. The dichloro ligands are bent away from their axial positions toward the diamine ligand forming ClRuCl angles of 165.61°, resonating to the steric effect of the phenyls in the etherphosphine ligands. In the crystal structure there is a number of RuCl···H2N contacts smaller than 3.0 Å at the same molecule, indicating the presence of unconventional intra-hydrogen bonds.

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Coordination chemistry and catalysis with hemilabile oxygen-phosphorus ligands

Cited by 804 publications

References 199 publications

Threefold symmetric trimetallic macrocycles formed via the Weak-Link Approach

Crystal structure of trans-dichloro-1,3-propanediamine-bis[(2-methoxyethyl) diphenylphosphine]ruthenium(II), RuCl2(C3H10N2)(C15H17OP)2

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