Synthesis and Structural Characterization of Late Transition Metal Parent Amido (LnM-NH2) Complexes: An Acid/Conjugate Base Metathesis Approach

Kaplan, Anne W.; Ritter, Joachim; Bergman, Robert G.

doi:10.1021/ja980632+

Cited by 50 publications

(68 citation statements)

References 22 publications

(18 reference statements)

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“…Searching the Cambridge Structural Database, we found that NaCl complexes with a NaÀCl bond length between 2.64 and 3.05 can be found (for crystalline NaCl the value is 2.82 ). [35] This was confirmed by a computational study, performed to compare the structural parameters of our metallacrowns with the optimized structures of the corresponding [12]crown-3 alkali metal halide complexes. A similar situation is encountered for 1´NaI (NaÀI 2.97 ) and 2´NaBr (NaÀBr 2.73 ).…”

Section: Structural and Theoretical Investigationssupporting

confidence: 62%

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

et al. 2001

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The reaction of [(arene)RuCl2]2 (arene = C6H6, cymene, C6H3Et3, or C6Me6) or [Cp*RhCl2]2 with 3-hydroxy-2-pyridone in the presence of Cs2CO3 gives trinuclear metallamacrocyclic complexes. The self-assembly process was shown to be completely diastereoselective, and a racemic mixture of complexes with M(R)M(R)M(R) or MsMsMs (M=Ru, Rh) configuration was obtained. Plausible mononuclear intermediates of the formula [(arene)RuCl(C5H4NO2)] (arene = cymene, C6Me6) have been isolated and characterized. A structurally related trimer was synthesized by using [(cymene)RuCl2]2 and 3-acetamido-2-pyridone instead of 3-hydroxy-2-pyridone. The macrocycles were shown to be highly potent ionophores for Na+ and/or Li+ with negligible affinities for the larger cation K+. The selectivities of the receptors depend on the pi-ligand present: whereas the (C6H6)Ru- and (cymene)Ru complexes bind both Li+ and Na+, the (C6Me6)Ru-, (C6H3Et3)Ru-, and Cp*Rh complexes bind exclusively Li+. For all receptors, the presence of alkali metal ions can be detected electrochemically: the peak potential is shifted by > 300 mV toward anionic potential upon binding. This behavior was utilized to detect Li+ and Na+ colorimetrically. Single crystal X-ray analyses have been carried out on eight complexes, four of which are bound to an alkali metal halide ion pair. Structural parameters, which affect the affinity and selectivity are discussed. A computational study on [[MX][12]crown-3] complexes (M =Li, Na; X=Cl, Br, I) was performed in order to compare relevant bond lengths and angles of the energy-minimized structures with those of the organometallic receptors.

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Section: Structural and Theoretical Investigationssupporting

confidence: 62%

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

et al. 2001

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“…[16] In an effort to optimize the synthetic protocol for this compound, we pursued an alternative approach, in the hope of avoiding contamination of the amide with sodium halides or other, possibly destabilizing, impurities. Deprotonation of ammine complexes with strong bases, such as potassium hydride or organolithium reagents, is a synthetic protocol that has been successfully employed in the generation of amido species.…”

Section: Resultsmentioning

confidence: 99%

“…(16)) are formed in solution through displacement of the amido group by the incoming ligand followed by deprotonation of a methyl group on the Cp* ring and liberation of ammonia. Conclusive evidence for the presence of the Ir-bonded h 4 -tetramethylfulvene moiety in the solid state has been provided by an X-ray diffraction study of complex 16.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Reactivity of the Monomeric Late‐Transition‐Metal Parent Amido Complex [Ir(Cp*)(PMe₃)(Ph)(NH₂)]

Rais

Bergman

2004

Chemistry A European J

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The late-transition-metal parent amido compound [Ir(Cp*)(PMe3)(Ph)(NH2)] (2) has been synthesized by deprotonation of the corresponding ammine complex [Ir(Cp*)(PMe3)(Ph)(NH3)][OTf] (6) with KN(SiMe3)2. An X-ray structure determination has ascertained its monomeric nature. Proton-transfer studies indicate that 2 can successfully deprotonate p-nitrophenylacetonitrile, aniline, and phenol. Crystallographic analysis has revealed that the ion pair [Ir(Cp*)(PMe3)(Ph)(NH3)][OPh] (8) exists as a hydrogen-bonded dimer in the solid state. Reactions of 2 with isocyanates and carbodiimides lead to overall insertion of the heterocumulenes into the N--H bond of the Ir-bonded amido group, demonstrating the ability of 2 to act as an efficient nucleophile. Intriguing reactivity is observed when amide 2 reacts with CO or 2,6-dimethylphenyl isocyanide. eta4-Tetramethylfulvene complexes [Ir(eta4-C5Me4CH2)(PMe3)(Ph)(L)] (L=CO (15), CNC6H3-2,6-(CH3)2 (16)) are formed in solution through displacement of the amido group by the incoming ligand followed by deprotonation of a methyl group on the Cp* ring and liberation of ammonia. Conclusive evidence for the presence of the Ir-bonded eta4-tetramethylfulvene moiety in the solid state has been provided by an X-ray diffraction study of complex 16.

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“…1). Although no terminal amido complexes have previously been prepared by the oxidative addition of ammonia (3)(4)(5), several terminal amido complexes of the late transition metals have been prepared by other routes during the past several years (6)(7)(8)(9). The reaction chemistry of these terminal amido complexes is beginning to unfold and, thus far, encompasses reactions with electrophiles, weak acids, nonpolar reagents such as hydrogen, and unsaturated reagents such as CO (9)(10)(11)(12)(13).…”

mentioning

confidence: 99%

Oxidative Addition of Ammonia to Form a Stable Monomeric Amido Hydride Complex

Zhao

Goldman

Hartwig

2005

Science

423

289

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The insertion of an iridium complex into an N-H bond in ammonia leads to a stable monomeric amido hydride complex in solution at room temperature. This reaction advances the transition-metal coordination chemistry of ammonia beyond its role for more than a century as an ancillary ligand. The precursor for this insertion reaction is an iridium(I) olefin complex with an aliphatic ligand containing one carbon and two phosphorus donor atoms. Kinetic and isotopic labeling studies indicate that olefin dissociates to give a 14-electron iridium(I) fragment, which then reacts with ammonia. This cleavage of the N-H bond under neutral conditions provides a foundation on which to develop future mild catalytic transformations of ammonia, such as olefin hydroamination and arene oxidative amination.

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Synthesis and Structural Characterization of Late Transition Metal Parent Amido (L_nM-NH₂) Complexes: An Acid/Conjugate Base Metathesis Approach

Cited by 50 publications

References 22 publications

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

Synthesis and Reactivity of the Monomeric Late‐Transition‐Metal Parent Amido Complex [Ir(Cp*)(PMe₃)(Ph)(NH₂)]

Oxidative Addition of Ammonia to Form a Stable Monomeric Amido Hydride Complex

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Synthesis and Structural Characterization of Late Transition Metal Parent Amido (LnM-NH2) Complexes: An Acid/Conjugate Base Metathesis Approach

Cited by 50 publications

References 22 publications

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

Self-Assembled Organometallic [12]Metallacrown-3 Complexes

Synthesis and Reactivity of the Monomeric Late‐Transition‐Metal Parent Amido Complex [Ir(Cp*)(PMe3)(Ph)(NH2)]

Oxidative Addition of Ammonia to Form a Stable Monomeric Amido Hydride Complex

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Synthesis and Structural Characterization of Late Transition Metal Parent Amido (L_nM-NH₂) Complexes: An Acid/Conjugate Base Metathesis Approach

Synthesis and Reactivity of the Monomeric Late‐Transition‐Metal Parent Amido Complex [Ir(Cp*)(PMe₃)(Ph)(NH₂)]