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Hideo Nagashima - One of the best experts on this subject based on the ideXlab platform.
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Preparation and Structural Elucidation of Unusually Thermally Stable Novel Alkylruthenium Complexes Bearing Amidin’ate Ligands， （n6－C6H6）Ru（n－amidinate）R （R ＝ Me ， Et ， Bn）
2016Co-Authors: Taizo Hayashida, Hideo NagashimaAbstract:The first organoruthenium Amidinates bearing a Ru－C 6 bond were prepared ， and their stmctures were elucidated by spectroscopy and crystallography ． A halogenoruthenium amidinate precursor ， ［（n 6－C6H6）Ru（n－tBuNCPhNtBu）Cl］ ， was treated with Grignard reagents to form thermally and air stable alky1 ruthenium complexes ， ［（n6－C6H6）Ru（n一‘BuNCPhNtBu）R ］ （R ＝ Me （3a） ， Et （3b） ， Bn （3c）） ． C，一symmetric ‘piano stool ’ structures of these complexes were suggested from NMR spectroscopic data ． These were supported by crystallographic studies of 3b and 3c
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trifluoromethanesulfonate triflate as a moderately coordinating anion studies from chemistry of the cationic coordinatively unsaturated mono and diruthenium Amidinates
Journal of Organometallic Chemistry, 2007Co-Authors: Taizo Hayashida, Hideo Kondo, Karl Kirchner, Junichi Terasawa, Yusuke Sunada, Hideo NagashimaAbstract:Abstract Triflate complexes of mono- and diruthenium Amidinates, (η6-C6R6)Ru(κ1-OTf){η2-R′N C(R′′)NR′} (1: R = Me; 2: R = H) and (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5R5) (3: R = Me; 4: R = H), are synthesized, and coordination behavior of the triflate anion to the coordinatively unsaturated ruthenium species is investigated by crystallography and variable temperature (VT) NMR spectroscopy (19F, 1H). The monoruthenium amidinate complexes have three-legged piano-stool structures in single crystals, which include a κ1-OTf ligand with the Ru–O bond of 2.15–2.20 A. In contrast, reversible dissociation of OTf is observed in variable temperature 1H NMR spectroscopy in liquid states; the activation energy for the dissociation and recombination of the OTf ligand is varied with the substituents on the arene and amidinate ligand in the corresponding ruthenium cation and the solvent used. A typical example of moderately coordinating ability of the OTf ligand is seen in 19F NMR spectra of (η6-C6Me6)Ru(κ1-OTf){η2-iPrN C(Me)NiPr} (1a) and (η6-C6H6)Ru(κ1-OTf){η2-iPrN C(Me)NiPr} (2a) in CD2Cl2 at the temperature range from −90 to 20 °C, in which the OTf anion is dissociated in 1a, whereas 2a has a relatively robust Ru–OTf bond. Combination of crystallography and VT NMR contributes to understanding the difference in coordination behavior of the OTf ligand between two diruthenium Amidinates, (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5Me5) (3) and (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5H5) (4); the results suggest that the electron-donating and sterically demanding η5-C5Me5 helps for dissociation of the triflate ligand. Moderate coordinating ability of the triflate anion sometimes provides characteristic reactions of mono- and diruthenium Amidinates which differ from the corresponding neutral halogeno-compounds or cationic coordinatively unsaturated homologues bearing fluorinated tetraarylborates; a typical example is given by inhibition of coordination of ethylene to the [(η6-C6H6)Ru{η2-tBuN C(Ph)NtBu}]+ species by the OTf ligand.
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“Unsymmetrical” Diruthenium Amidinates in Which the μ2-Amidinate Bridge Is Perpendicular to the Ru−Ru Axis: Synthesis and Reactions of Derivatives of [(η5-C5Me5)Ru(μ-amidinate)Ru(η5-C5H5)]+
Organometallics, 2005Co-Authors: Junichi Terasawa, Hideo Kondo, Karl Kirchner, Taisuke Matsumoto, Yukihiro Motoyama, Hideo NagashimaAbstract:New diruthenium complexes, of which two organoruthenium species, (η5-C5Me5)Ru and (η5-C5H5)Ru, are linked by a bridging amidinate ligand, were synthesized and characterized. Treatment of (η5-C5Me5)Ru(η-amidinate) [amidinate: iPrNC(Me)NiPr] with [(η5-C5H5)Ru(η-NCMe)3]+PF6- resulted in formation of a cationic diruthenium amidinate, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)(η-NCMe)]+PF6- (4), which was converted to (η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)X [X = Cl (5a), Br (5b)] by treatment with the halide anion. The molecular structures and spectroscopic data of 4 and 5a including their solution dynamics are compared with their bis-pentamethylcyclopentadienyl homologues, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5Me5)(η-NCMe)]+PF6- and (η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)Cl. Treatment of 5a with TlBF4 produced a diruthenium complex, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)]+BF4- (6), bearing 34 valence electrons, which was isolated and characterized by spectroscopy. The coordinatively unsaturated nature of 6 was evidenc...
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Chemistry of coordinatively unsaturated organoruthenium Amidinates as entry to homogeneous catalysis
Coordination Chemistry Reviews, 2003Co-Authors: Hideo Nagashima, Hideo Kondo, Taizo Hayashida, Yoshitaka Yamaguchi, Mitsuru Gondo, Satoshi Masuda, Kazuma Miyazaki, Kouki Matsubara, Karl KirchnerAbstract:The chemistry of coordinatively unsaturated organoruthenium complexes is reviewed in this article. In particular, the subject is focused on neutral and cationic organoruthenium Amidinates, which formally have 16 valence electrons and show signs of coordinative unsaturation. The ruthenium Amidinates, ( 5 -C5Me5)Ru(-amidinate) (1), and their isoelectronic analogues, [( 6 -arene)Ru(-amidinate)] + (2), are synthesized and characterized; a possible stabilizing factor of the unsaturated metal center is weak coordination of -electrons in the Amidinates ligands. Reactions of various two-electron donor ligands with 1 or 2 reveal the strong -donor property of 1 and Lewis acid nature of 2. One or two-electron redox processes of 1 in the reactions with organic halides are studied by isolation of the corresponding Ru(III) and Ru(IV) products; the results lead to their catalysis for the Tsuji–Trost reaction and the intramolecular Kharasch reaction. The treatment of 2 with trimethylsilyldiazomethane results in the formation of cationic amidinato-carbene complexes, which involve unusual reversible metal-to-carbon silyl group migration. © 2003 Elsevier B.V. All rights reserved.
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Access to Novel Ruthenium−Amidinate Complexes, (η6-arene)Ru(η2-amidinate)X and [Ru(η2-amidinate)(MeCN)4]+PF6- by Photochemical Displacement of the Benzene Ligand in (η6-C6H6)Ru(η2-amidinate)X
Organometallics, 2002Co-Authors: Taizo Hayashida, Hideo NagashimaAbstract:Novel ruthenium−amidinate complexes, (η6-C6H5R)Ru(η2-amidinate)X (R = Me, OMe, F) (4) and [Ru(η2-amidinate)(MeCN)4]+PF6- (5) are synthesized by photochemical displacement of the benzene ligand in (η6-C6H6)Ru(η2-amidinate)X (3) by arenes or MeCN. The acetonitrile ligands of 5 are easily replaceable by other σ-donor ligands (L) such as pyridines, phosphines, and isocyanides to afford the corresponding derivatives, [Ru(η2-amidinate)(MeCN)n(L)4-n+]PF6- (n = 1 or 2).
Frank T Edelmann - One of the best experts on this subject based on the ideXlab platform.
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Crystal and mol-ecular structures of two silver(I) Amidinates, including an unexpected co-crystal with a lithium amidinate.
Acta Crystallographica Section E Crystallographic Communications, 2016Co-Authors: Sida Wang, Nicole Harmgarth, Phil Liebing, Frank T EdelmannAbstract:The silver(I) Amidinates bis[μ-N1,N2-bis(propan-2-yl)benzamidinato-κ2N1:N2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(NiPr)2}]2 (1), and bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2N1:N2)disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5–C≡C–C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2N1:N2)disilver(I) bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ3N1,N2:N1)bis(tetrahydrofuran-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5–C≡C–C(NCy)2}]2[Li{cyclo-C3H5–C≡C–C(NCy)2}(THF)]2·C7H8, composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetrahedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN′ coordination, while it is a μ-κN:κN:κN′-coordination in the case of lithium derivative 2b.
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Crystal and molecular structures of two silver(I) Amidinates, including an unexpected co-crystal with a lithium amidinate
International Union of Crystallography, 2016Co-Authors: Sida Wang, Nicole Harmgarth, Phil Liebing, Frank T EdelmannAbstract:The silver(I) Amidinates bis[μ-N1,N2-bis(propan-2-yl)benzamidinato-κ2N1:N2]disilver(I), [Ag2(C13H19N2)2] or [Ag{PhC(NiPr)2}]2 (1), and bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2N1:N2)disilver(I), [Ag2(C18H27N2)2] or [Ag{cyclo-C3H5–C[triple-bond]C–C(NCy)2}]2 (2a), exist as centrosymmetric dimers with a planar Ag2N4C2 ring and a common linear coordination of the metal atoms in the crystalline state. Moiety 2a forms a co-crystal with the related lithium amidinate, namely bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ2N1:N2)disilver(I) bis(μ-N1,N2-dicyclohexyl-3-cyclopropylpropynamidinato-κ3N1,N2:N1)bis(tetrahydrofuran-κO)lithium(I) toluene monosolvate, [Ag2(C18H27N2)2][Li2(C18H27N2)2(C4H8O)2]·C7H8 or [Ag{cyclo-C3H5–C[triple-bond]C–C(NCy)2}]2[Li{cyclo-C3H5–C[triple-bond]C–C(NCy)2}(THF)]2·C7H8, composed as 2a × 2b × toluene. The lithium moiety 2b features a typical ladder-type dimeric structure with a distorted tetrahedral coordination of the metal atoms. In the silver(I) derivatives 1 and 2a, the amidinate ligand adopts a μ-κN:κN′ coordination, while it is a μ-κN:κN:κN′-coordination in the case of lithium derivative 2b
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chapter two recent progress in the chemistry of metal Amidinates and guanidinates syntheses catalysis and materials
Advances in Organometallic Chemistry, 2013Co-Authors: Frank T EdelmannAbstract:This review provides a comprehensive overview of the most recent progress in chemistry and applications of metal complexes containing heteroallylic ligands such as Amidinates and guanidinates. Clearly, the coordination chemistry of Amidinates and guanidinates has reached a state of maturity and continues to be a highly popular area of research. These heteroallylic ligand systems allow a wealth of variations and modifications, making a larger ligand library available than in cyclopentadienyl chemistry. Exciting results have been obtained in recent years for almost any metallic elements in the Periodic Table. Truly remarkable developments include, for example, the chemistry of cyclic amidinate-based silylenes and the stabilization of metal–metal quadruply and quintuple bonds by amidinate and guanidinate ligands. The range of applications for metal Amidinates and guanidinates in homogeneous catalysis has considerably broadened in recent years. In materials science, alkyl-substituted metal Amidinates and guanidinates are now well established as volatile precursors for a variety of ALD and MOCVD processes. Without doubt the chemistry of metal Amidinates and guanidinates and related complexes will continue to produce exciting results and applications in the years to come.
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Recent Progress in the Chemistry of Metal Amidinates and Guanidinates: Syntheses, Catalysis and Materials
Advances in Organometallic Chemistry, 2013Co-Authors: Frank T EdelmannAbstract:Abstract This review provides a comprehensive overview of the most recent progress in chemistry and applications of metal complexes containing heteroallylic ligands such as Amidinates and guanidinates. Clearly, the coordination chemistry of Amidinates and guanidinates has reached a state of maturity and continues to be a highly popular area of research. These heteroallylic ligand systems allow a wealth of variations and modifications, making a larger ligand library available than in cyclopentadienyl chemistry. Exciting results have been obtained in recent years for almost any metallic elements in the Periodic Table. Truly remarkable developments include, for example, the chemistry of cyclic amidinate-based silylenes and the stabilization of metal–metal quadruply and quintuple bonds by amidinate and guanidinate ligands. The range of applications for metal Amidinates and guanidinates in homogeneous catalysis has considerably broadened in recent years. In materials science, alkyl-substituted metal Amidinates and guanidinates are now well established as volatile precursors for a variety of ALD and MOCVD processes. Without doubt the chemistry of metal Amidinates and guanidinates and related complexes will continue to produce exciting results and applications in the years to come.
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Homoleptic Gadolinium Amidinates as Precursors for MOCVD of Oriented Gadolinium Nitride (GdN) Thin Films
2013Co-Authors: Michael Krasnopolski, Frank T Edelmann, Cristian G. Hrib, Rüdiger W. Seidel, Manuela Winter, Hans-werner Becker, Detlef Rogalla, Roland A. Fischer, Anjana DeviAbstract:Five new homoleptic gadolinium tris-amidinate complexes are reported, which were synthesized via the salt-elimination reaction of GdCl3 with 3 equiv of lithiated symmetric and asymmetric Amidinates at ambient temperature. The Gd-tris-Amidinates [Gd{(NiPr)2CR}3] [R = Me (1), Et (2), tBu (3), nBu (4)] and [Gd{(NEt)(NtBu)CMe}3] (5) are solids at room temperature and sublime at temperatures of about 125 °C (6 × 10–2 mbar) with the exception of compound 4, which is a viscous liquid at room temperature. According to X-ray diffraction analysis of 3 and 5 as representative examples of the series, the complexes adopt a distorted octahedral structure in the solid state. Mass spectrometric (MS) data confirmed the monomeric structure in the gas phase, and high-resolution MS allowed the identification of characteristic fragments, such as [{(NiPr)2CR}GdCH3]+ and [{(NiPr)2CR}GdNH]+. The alkyl substitution patterns of the amidinate ligands clearly show an influence on the thermal properties, and specifically, the introduction of the asymmetric carbodiimide leads to a lowering of the onset of volatilization and decomposition. Compound 5, which is the first Gd complex with an asymmetric amidinate ligand system to be reported, was, therefore, tested for the MOCVD of GdN thin films. The as-deposited GdN films were capped with Cu in a subsequent MOCVD process to prevent postdeposition oxidation of the films. Cubic GdN on Si(100) substrates with a preferred orientation in the (200) direction were grown at 750 °C under an ammonia atmosphere and exhibited a columnar morphology and low levels of C or O impurities according to scanning electron microscopy, Rutherford backscattering, and nuclear reaction analysis
Karl Kirchner - One of the best experts on this subject based on the ideXlab platform.
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trifluoromethanesulfonate triflate as a moderately coordinating anion studies from chemistry of the cationic coordinatively unsaturated mono and diruthenium Amidinates
Journal of Organometallic Chemistry, 2007Co-Authors: Taizo Hayashida, Hideo Kondo, Karl Kirchner, Junichi Terasawa, Yusuke Sunada, Hideo NagashimaAbstract:Abstract Triflate complexes of mono- and diruthenium Amidinates, (η6-C6R6)Ru(κ1-OTf){η2-R′N C(R′′)NR′} (1: R = Me; 2: R = H) and (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5R5) (3: R = Me; 4: R = H), are synthesized, and coordination behavior of the triflate anion to the coordinatively unsaturated ruthenium species is investigated by crystallography and variable temperature (VT) NMR spectroscopy (19F, 1H). The monoruthenium amidinate complexes have three-legged piano-stool structures in single crystals, which include a κ1-OTf ligand with the Ru–O bond of 2.15–2.20 A. In contrast, reversible dissociation of OTf is observed in variable temperature 1H NMR spectroscopy in liquid states; the activation energy for the dissociation and recombination of the OTf ligand is varied with the substituents on the arene and amidinate ligand in the corresponding ruthenium cation and the solvent used. A typical example of moderately coordinating ability of the OTf ligand is seen in 19F NMR spectra of (η6-C6Me6)Ru(κ1-OTf){η2-iPrN C(Me)NiPr} (1a) and (η6-C6H6)Ru(κ1-OTf){η2-iPrN C(Me)NiPr} (2a) in CD2Cl2 at the temperature range from −90 to 20 °C, in which the OTf anion is dissociated in 1a, whereas 2a has a relatively robust Ru–OTf bond. Combination of crystallography and VT NMR contributes to understanding the difference in coordination behavior of the OTf ligand between two diruthenium Amidinates, (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5Me5) (3) and (η5-C5Me5)Ru(μ-η2-iPrN C(Me)NiPr)Ru(κ1-OTf)(η5-C5H5) (4); the results suggest that the electron-donating and sterically demanding η5-C5Me5 helps for dissociation of the triflate ligand. Moderate coordinating ability of the triflate anion sometimes provides characteristic reactions of mono- and diruthenium Amidinates which differ from the corresponding neutral halogeno-compounds or cationic coordinatively unsaturated homologues bearing fluorinated tetraarylborates; a typical example is given by inhibition of coordination of ethylene to the [(η6-C6H6)Ru{η2-tBuN C(Ph)NtBu}]+ species by the OTf ligand.
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“Unsymmetrical” Diruthenium Amidinates in Which the μ2-Amidinate Bridge Is Perpendicular to the Ru−Ru Axis: Synthesis and Reactions of Derivatives of [(η5-C5Me5)Ru(μ-amidinate)Ru(η5-C5H5)]+
Organometallics, 2005Co-Authors: Junichi Terasawa, Hideo Kondo, Karl Kirchner, Taisuke Matsumoto, Yukihiro Motoyama, Hideo NagashimaAbstract:New diruthenium complexes, of which two organoruthenium species, (η5-C5Me5)Ru and (η5-C5H5)Ru, are linked by a bridging amidinate ligand, were synthesized and characterized. Treatment of (η5-C5Me5)Ru(η-amidinate) [amidinate: iPrNC(Me)NiPr] with [(η5-C5H5)Ru(η-NCMe)3]+PF6- resulted in formation of a cationic diruthenium amidinate, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)(η-NCMe)]+PF6- (4), which was converted to (η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)X [X = Cl (5a), Br (5b)] by treatment with the halide anion. The molecular structures and spectroscopic data of 4 and 5a including their solution dynamics are compared with their bis-pentamethylcyclopentadienyl homologues, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5Me5)(η-NCMe)]+PF6- and (η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)Cl. Treatment of 5a with TlBF4 produced a diruthenium complex, [(η5-C5Me5)Ru(μ2-amidinate)Ru(η5-C5H5)]+BF4- (6), bearing 34 valence electrons, which was isolated and characterized by spectroscopy. The coordinatively unsaturated nature of 6 was evidenc...
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Chemistry of coordinatively unsaturated organoruthenium Amidinates as entry to homogeneous catalysis
Coordination Chemistry Reviews, 2003Co-Authors: Hideo Nagashima, Hideo Kondo, Taizo Hayashida, Yoshitaka Yamaguchi, Mitsuru Gondo, Satoshi Masuda, Kazuma Miyazaki, Kouki Matsubara, Karl KirchnerAbstract:The chemistry of coordinatively unsaturated organoruthenium complexes is reviewed in this article. In particular, the subject is focused on neutral and cationic organoruthenium Amidinates, which formally have 16 valence electrons and show signs of coordinative unsaturation. The ruthenium Amidinates, ( 5 -C5Me5)Ru(-amidinate) (1), and their isoelectronic analogues, [( 6 -arene)Ru(-amidinate)] + (2), are synthesized and characterized; a possible stabilizing factor of the unsaturated metal center is weak coordination of -electrons in the Amidinates ligands. Reactions of various two-electron donor ligands with 1 or 2 reveal the strong -donor property of 1 and Lewis acid nature of 2. One or two-electron redox processes of 1 in the reactions with organic halides are studied by isolation of the corresponding Ru(III) and Ru(IV) products; the results lead to their catalysis for the Tsuji–Trost reaction and the intramolecular Kharasch reaction. The treatment of 2 with trimethylsilyldiazomethane results in the formation of cationic amidinato-carbene complexes, which involve unusual reversible metal-to-carbon silyl group migration. © 2003 Elsevier B.V. All rights reserved.
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Isolable Yet Highly Reactive Cationic Organoruthenium(II) Amidinates, [Ru(η6-C6R6)(η-amidinate)]+X−, Showing Signs of Coordinative Unsaturation: Isoelectronic Complexes of Ru(η5-C5Me5)(η-amidinate)
Chemistry Letters, 2001Co-Authors: Taizo Hayashida, Yoshitaka Yamaguchi, Karl Kirchner, Hideo NagashimaAbstract:The coordinatively unsaturated ruthenium(II) complexes [Ru(η6-C6R6)(η-amidinate)]+X− (R = H, Me, X = TFPB, PF6), being isoelectronic with Ru(η5-C5Me5)(η-amidinate), have been isolated and characterized by spectroscopy and crystallography. A weak π-coordination of the amidinate ligands in the solid state was observed by X-ray crystallography. DFT calculations also suggest that such a coordination mode contributes to the stabilization of these complexes. These complexes behave as highly reactive transition metal Lewis acids in the reactions with various two-electron donor ligands.
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isolable yet highly reactive cationic organoruthenium ii Amidinates ru η6 c6r6 η amidinate x showing signs of coordinative unsaturation isoelectronic complexes of ru η5 c5me5 η amidinate
Chemistry Letters, 2001Co-Authors: Taizo Hayashida, Yoshitaka Yamaguchi, Karl Kirchner, Hideo NagashimaAbstract:The coordinatively unsaturated ruthenium(II) complexes [Ru(η6-C6R6)(η-amidinate)]+X− (R = H, Me, X = TFPB, PF6), being isoelectronic with Ru(η5-C5Me5)(η-amidinate), have been isolated and characterized by spectroscopy and crystallography. A weak π-coordination of the amidinate ligands in the solid state was observed by X-ray crystallography. DFT calculations also suggest that such a coordination mode contributes to the stabilization of these complexes. These complexes behave as highly reactive transition metal Lewis acids in the reactions with various two-electron donor ligands.
Peter W. Roesky - One of the best experts on this subject based on the ideXlab platform.
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Mono- and bimetallic amidinate samarium complexes – synthesis, structure, and hydroamination catalysis
Dalton transactions (Cambridge England : 2003), 2019Co-Authors: Neda Kazeminejad, Michael T. Gamer, Luca Münzfeld, Peter W. RoeskyAbstract:In order to investigate the difference between mono- and bimetallic systems in the catalytic hydroamination/cyclization reaction two mono- and bimetallic amidinate samarium catalysts, featuring comparable coordination environments, were synthesized. Both systems comprise two {N(SiMe3)2}− leaving groups to minimize the steric influence of the corresponding amidinate ligand. The bimetallic system is based on a bis(amidinate) 4,6-dibenzofuran derivative, while N,N′-bis(2,6-diisopropylphenyl)benzamidinate was employed as ligand for the monometallic catalyst. For the hydroamination/cyclization reaction five different substrates were investigated. Additionally, kinetic studies were carried out to gain deeper understanding of the mechanism.
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Rhodium(I) and Iridium(I) Complexes of Ferrocenyl-Functionalized Amidinates and Bis(Amidinates): κ2N-Coordination Versus Ferrocenyl Ortho-Metalation
Organometallics, 2019Co-Authors: Sebastian Kaufmann, Michael Radius, Eric Moos, Frank Breher, Peter W. RoeskyAbstract:The synthesis and characterization of two bulky ferrocenyl-functionalized Amidinates and their lithium, potassium, rhodium(I), and iridium(I) complexes are reported. The ferrocenyl mono(amidine) [Fc{C(NDipp)(NHDipp)}] (1) (Fc = ferrocenyl; Dipp = 2,6-diisopropylphenyl) and its potassium complex [Fc{C(NDipp)2K}·3THF] (2) as well as the 1,1′-ferrocendiyl-bridged bis(amidinate) [fc{C(NMes)2Li}2·3THF] (3) (fc = ferrocene-1,1′-diyl; Mes = mesityl) were synthesized. Salt metathesis reactions with the metal precursors [Rh(cod)Cl]2 (cod = 1,5-cyclooctadiene) and [Ir(cod)Cl]2 gave the rhodium(I) and iridium(I) complexes [Fc{C(NDipp)2Rh(cod)}] (4), [fc{C(NMes)2Rh(cod)}2] (5), and [fc{C(NMes)2Ir(cod)}2] (6), as well as the ortho-metalated compound [(Cp)Fe(C5H3){C(NHDipp)(NDipp)Ir(cod)}] (7). As complex 7 showed an ortho-metalation on the ferrocene backbone, we investigated this reaction in more detail. It was found that the rhodium(I) complexes 4 and 5 also undergo ortho-metalation upon treatment with carbon monoxid...
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Rhodium(I) and Iridium(I) Complexes of Ferrocenyl-Functionalized Amidinates and Bis(Amidinates): κ2N‑Coordination Versus Ferrocenyl Ortho-Metalation
2019Co-Authors: Sebastian Kaufmann, Michael Radius, Eric Moos, Frank Breher, Peter W. RoeskyAbstract:The synthesis and characterization of two bulky ferrocenyl-functionalized Amidinates and their lithium, potassium, rhodium(I), and iridium(I) complexes are reported. The ferrocenyl mono(amidine) [Fc{C(NDipp)(NHDipp)}] (1) (Fc = ferrocenyl; Dipp = 2,6-diisopropylphenyl) and its potassium complex [Fc{C(NDipp)2K}·3THF] (2) as well as the 1,1′-ferrocendiyl-bridged bis(amidinate) [fc{C(NMes)2Li}2·3THF] (3) (fc = ferrocene-1,1′-diyl; Mes = mesityl) were synthesized. Salt metathesis reactions with the metal precursors [Rh(cod)Cl]2 (cod = 1,5-cyclooctadiene) and [Ir(cod)Cl]2 gave the rhodium(I) and iridium(I) complexes [Fc{C(NDipp)2Rh(cod)}] (4), [fc{C(NMes)2Rh(cod)}2] (5), and [fc{C(NMes)2Ir(cod)}2] (6), as well as the ortho-metalated compound [(Cp)Fe(C5H3){C(NHDipp)(NDipp)Ir(cod)}] (7). As complex 7 showed an ortho-metalation on the ferrocene backbone, we investigated this reaction in more detail. It was found that the rhodium(I) complexes 4 and 5 also undergo ortho-metalation upon treatment with carbon monoxide (CO). After the carbonylation, the first known ortho-metalation of rhodium(I) on ferrocene complexes was observed for [(Cp)Fe{(C5H3)C(NHDipp)(NDipp)Rh(CO)2}] (8) and [Fe(C5H3)2{C(NHMes)(NMes)Rh(CO)2}2] (9). A combined electrochemical and quantum chemical study revealed that depending on both the metal-bound ligand (CO vs cod) and the bonding mode (κ2N vs ortho-metalated), the highest occupied molecular orbital is located more on iron or on rhodium/iridium
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Enantiopure amidinate complexes of lutetium
Journal of Organometallic Chemistry, 2017Co-Authors: Tobias S. Brunner, Peter W. RoeskyAbstract:Abstract Two new enantiomeric pure Amidinates N,N’-bis-((R)-1-cyclohexylethyl)benzamidinate ((R)-CEBA)- and N,N’-bis-((S)-1-phenylethyl)acetamidinate ((S)-PEAA)- were synthesized by two different synthetic pathways. The chiral amidine (R)-HCEBA was synthesized via the so-called imidoylchloride route. The corresponding lithium derivative (R)-LiCEBA was best obtained by deprotonation of the amidinate hydrochloride (R)-HCEBA·HCl. In contrast (S)-LiPEAA was most efficiently accessed by reaction of methyllithium with bis-((S)-1-phenylethyl)carbodiimide. Further reactions of these lithium salts with LuCl3 in a 2:1 ratio resulted in the enantiomeric pure bisamidinate lutetium complexes [{(R)-CEBA}2Lu-μ-Cl]2 and [{(S)-PEAA}2LuCl(thf)], which are either dimeric or monomeric in the solid state.
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Enantiopure Amidinate Complexes of the Rare-Earth Elements
Organometallics, 2016Co-Authors: Tobias S. Brunner, Paul Benndorf, Michael T. Gamer, Nicolai D. Knöfel, Katharina Gugau, Peter W. RoeskyAbstract:The synthesis of the new chiral amidine (S,S)-N,N′-bis(1-phenylethyl)pivalamidine ((S)-HPETA) and its corresponding lithium salt (S)-LiPETA are reported, and their solid-state structures were investigated by single-crystal X-ray diffraction. Depending on the stoichiometric ratio and the ion radius of the rare-earth metal, the reaction of (S)-LiPETA with anhydrous lanthanide trihalides (Ln = Sc, Y, La, Nd, Sm, Lu) afforded mono-, bis-, and tris(amidinate) complexes. The mono(amidinate) compound [{(S)-PETA}LaI4Li2(thf)4], the bis(amidinate) complexes [({(S)-PETA}2Ln-μ-Cl)n] (Ln = Sc, Y, Nd, Sm, Lu), and the tris(amidinate) compound [{(S)-PETA}3Y] were isolated and structurally characterized by single-crystal X-ray diffraction. For the bis(amidinate) compounds, either monomeric or chloro-bridged dimeric structures were observed in the solid state. Furthermore, chiral bis(amidinate)-amido and -alkyl complexes [{(S)-PETA}2Ln{E(SiMe3)2}] (E = N, Ln = Y; E = CH, Ln = Sc, Y, Lu) were synthesized by salt metathesi...
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Chemistry of coordinatively unsaturated organoruthenium Amidinates as entry to homogeneous catalysis
Coordination Chemistry Reviews, 2003Co-Authors: Hideo Nagashima, Hideo Kondo, Taizo Hayashida, Yoshitaka Yamaguchi, Mitsuru Gondo, Satoshi Masuda, Kazuma Miyazaki, Kouki Matsubara, Karl KirchnerAbstract:The chemistry of coordinatively unsaturated organoruthenium complexes is reviewed in this article. In particular, the subject is focused on neutral and cationic organoruthenium Amidinates, which formally have 16 valence electrons and show signs of coordinative unsaturation. The ruthenium Amidinates, ( 5 -C5Me5)Ru(-amidinate) (1), and their isoelectronic analogues, [( 6 -arene)Ru(-amidinate)] + (2), are synthesized and characterized; a possible stabilizing factor of the unsaturated metal center is weak coordination of -electrons in the Amidinates ligands. Reactions of various two-electron donor ligands with 1 or 2 reveal the strong -donor property of 1 and Lewis acid nature of 2. One or two-electron redox processes of 1 in the reactions with organic halides are studied by isolation of the corresponding Ru(III) and Ru(IV) products; the results lead to their catalysis for the Tsuji–Trost reaction and the intramolecular Kharasch reaction. The treatment of 2 with trimethylsilyldiazomethane results in the formation of cationic amidinato-carbene complexes, which involve unusual reversible metal-to-carbon silyl group migration. © 2003 Elsevier B.V. All rights reserved.
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Isolable Yet Highly Reactive Cationic Organoruthenium(II) Amidinates, [Ru(η6-C6R6)(η-amidinate)]+X−, Showing Signs of Coordinative Unsaturation: Isoelectronic Complexes of Ru(η5-C5Me5)(η-amidinate)
Chemistry Letters, 2001Co-Authors: Taizo Hayashida, Yoshitaka Yamaguchi, Karl Kirchner, Hideo NagashimaAbstract:The coordinatively unsaturated ruthenium(II) complexes [Ru(η6-C6R6)(η-amidinate)]+X− (R = H, Me, X = TFPB, PF6), being isoelectronic with Ru(η5-C5Me5)(η-amidinate), have been isolated and characterized by spectroscopy and crystallography. A weak π-coordination of the amidinate ligands in the solid state was observed by X-ray crystallography. DFT calculations also suggest that such a coordination mode contributes to the stabilization of these complexes. These complexes behave as highly reactive transition metal Lewis acids in the reactions with various two-electron donor ligands.
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isolable yet highly reactive cationic organoruthenium ii Amidinates ru η6 c6r6 η amidinate x showing signs of coordinative unsaturation isoelectronic complexes of ru η5 c5me5 η amidinate
Chemistry Letters, 2001Co-Authors: Taizo Hayashida, Yoshitaka Yamaguchi, Karl Kirchner, Hideo NagashimaAbstract:The coordinatively unsaturated ruthenium(II) complexes [Ru(η6-C6R6)(η-amidinate)]+X− (R = H, Me, X = TFPB, PF6), being isoelectronic with Ru(η5-C5Me5)(η-amidinate), have been isolated and characterized by spectroscopy and crystallography. A weak π-coordination of the amidinate ligands in the solid state was observed by X-ray crystallography. DFT calculations also suggest that such a coordination mode contributes to the stabilization of these complexes. These complexes behave as highly reactive transition metal Lewis acids in the reactions with various two-electron donor ligands.
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Oxidative Addition of Allylic Substrates to Coordinatively Unsaturated Ruthenium Compounds, [Ru(η5-C5Me5)(η-amidinate)]: Preparation, Structure Elucidation, and Catalysis of Novel Ruthenium (IV)-η3-Allyl Complexes
Bulletin of the Chemical Society of Japan, 2001Co-Authors: Hideo Kondo, Yoshitaka Yamaguchi, Karl Kirchner, Akira Kageyama, Masa-aki Haga, Hideo NagashimaAbstract:Oxidative addition reactions of allylic halides, acetates, and carbonates with [Ru(η5-C5Me5)(η-amidinate)] [amidinate: iPrNC(Me)=NiPr (1a), tBuNC(Ph)=NtBu (1b)], which shows signs of coordinative unsaturation, gave novel cationic π-allyl ruthenium(IV) species. The compounds [Ru(η3-allyl)(η5-C5Me5)(η2-amidinate)]+X− were isolated by anion exchange of the products (X = PF6, BF4, BPh4), and were characterized by spectroscopic analysis. The crystallography of two of the [Ru(η3-allyl)(η5-C5Me5)(η2-amidinate)]+X− revealed a four-legged piano stool structure in which two nitrogen atoms in the amidinate ligand and two carbon atoms in the η3-allyl ligands occupy the positions of four legs; the orientation of the η3-allyl ligand was endo. Although cyclic voltammograms of the precursor, [Ru(η5-C5Me5)(η-amidinate)], indicated possible oxidative addition of organic halides other than allylic halides to [Ru(η5-C5Me5)(η-amidinate)], only allylic halides gave the corresponding Ru(IV) products. The importance of prior coo...
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(η5-C5Me5)Ru(amidinate): Highly Reactive Ruthenium Complexes Formally Bearing 16 Valence Electrons Showing Signs of Coordinative Unsaturation
Organometallics, 2000Co-Authors: Yoshitaka Yamaguchi, Hideo NagashimaAbstract:Novel coordinatively unsaturated ruthenium complexes, (η5-C5Me5)Ru(amidinate), were synthesized from [(η5-C5Me5)Ru(OMe)]2 and lithium Amidinates, which exist as monomers in both solution and solid ...
