A first mixed heteropentametallic transition metal complex: Synthesis and characterisation

Packheiser, Rico; Lang, Heinrich

doi:10.1016/j.inoche.2007.02.002

Cited by 26 publications

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“…Robust, and ideally modular, synthetic methodologies that permit ready assembly of metal-containing compounds and complexes would allow facile exploration of the chemical, physical, and optoelectronic features provided by metal complexes and design of new materials. Such modular methodologies for the construction of large heterometallic complexes which take advantage of the multiple coordination sites offered by ethynyl bipyridines was previously pursued by Lang in his “Tinkertoy” approach. − We have been recently focused on an allied approach to the construction of bimetallic complexes through the preparation of modular organometallic “coordinating tectons”. − A series of bimetallic complexes of the well-studied bifunctional ligand 5-ethynyl-2,2′-bipyridine were synthesized by this approach, and weak electronic communication was observed between two metal centers across this ligand . Indeed, the electronic interactions between metal termini separated by an organic functionality, M–bridge–M′, are often investigated in order to define the intramolecular electron transfer (or wirelike) characteristics of the assembly. − Investigations of organometallic complexes in this area have focused on the mixed-valence characteristics of bimetallic complexes derived from bridging moieties such as polyynes, − oligo(phenylene)ethynylenes, and bis(terpyridine)metal complexes .…”

Section: Introductionmentioning

confidence: 99%

Coordinating Tectons. Experimental and Computational Infrared Data as Tools To Identify Conformational Isomers and Explore Electronic Structures of 4-Ethynyl-2,2′-bipyridine Complexes

Mackenzie¹,

Bock²,

Lim³

et al. 2017

Organometallics

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4-Ethynyl-2,2'-bipyridyl substituted ruthenium alkynyl complexes have been prepared and used to access a range of binuclear homo-metallic ruthenium and hetero-metallic ruthenium-rhenium complexes. These have been characterized by a variety of spectroscopic and single-crystal X-ray diffraction experiments. The IR spectra of a number of these ruthenium alkynyls display multiple ν(C≡C) bands in the IR spectra, which are rationalized in terms of putative conformational isomers, whose calculated infrared stretching frequencies are comparable to those obtained experimentally. The mononuclear alkynyl complexes Ru(C≡C) undergo reversible one electron oxidations centered largely on the alkynyl ligands as inferred from the significant shift in ν(C≡C) frequency on oxidation, whilst the binuclear complex [Ru{C≡C-4bpy-κ 2-N,N'-RuClCp}(dppe)Cp*] + undergoes initial oxidation at the very electron rich {RuCl(bpy)Cp} fragment causing only a small change in ν(C≡C). A combination of IR and UV-vis spectroelectrochemical experiments, supported by quantum chemical calculations on a selected range of conformers, led to the classification of [Ru{C≡C-4-bpy-κ 2-N,N'-RuClCp}(dppe)Cp*] + as a weakly Class II mixed valence compound (H ab = 306 cm-1). These results indicate that there is improved electronic communication through the 4-ethynyl-2,2'-bipyridyl ligand compared to the analogous 5-ethynyl-2,2'-bipyridyl complexes (H ab = 17 cm-1).

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Section: Introductionmentioning

confidence: 99%

Coordinating Tectons. Experimental and Computational Infrared Data as Tools To Identify Conformational Isomers and Explore Electronic Structures of 4-Ethynyl-2,2′-bipyridine Complexes

Mackenzie¹,

Bock²,

Lim³

et al. 2017

Organometallics

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“…It is our goal to synthesize discrete molecular components that can be assembled into multinuclear complexes via a coordination chemistry methodology, i.e., coordinating tectons. − Specifically we seek also to develop these tectons as asymmetric components in order to provide facile synthetic access to heterometallic complexes, and thus more readily elucidate and tune the effects of a particular metal site on the molecular properties of the complex as a whole. Our lab and others have reported on transition metal σ-alkynyl complexes derived from 5-ethynyl-2,2′-bipyridine and the successful κ 2 -N,N′-complexation of additional d- and f-block metals to the pendant diimine moiety. ,− …”

Section: Introductionmentioning

confidence: 99%

Coordinating Tectons 4: Coordination Chemistry of the 4,5-Diazafluoren-9-yl Moiety as a Metallo-Ligand for Allenylidene Complexes

2015

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We describe how the 4,5-diazafluoren-9-yl moiety has been utilized in the construction of multinuclear complexes incorporating a ruthenium(II) allenylidene functionality. The coordination chemistry of diazafluorenylterminated allenylidene complexes is limited by the sensitivity (instability) of the allenylidene moiety under a variety of synthetic conditions. In contrast the κ 2 -N,N′-coordination of the diazafluorenyl propargylic alcohol (alkynol) to a metal center prior to allenylidene formation provides a facile route toward the synthesis of multinuclear allenylidene coordination complexes. Our synthetic attempts and successes are discussed in combination with spectroscopic and electronic characterization of the latter cases. ■ INTRODUCTIONThere exists a fundamental interest in the properties of multimetallic molecular complexes, to afford both understanding and applications in catalysis, 1−3 molecular electronics, 4−6 photochemistry, 7,8 and combinations thereof. 9−12 Of particular interest are those complexes in which the metal sites cooperate to yield synergistic properties largely absent in mononuclear analogues. To this end, molecules in which multiple metal sites are connected by conjugated organic bridges are of particular interest, as such bridging moieties are expected to foster increased degrees of interaction between the metal sites. The synergistic effects of the metal sites may then be readily tuned via synthetic modifications to the bridging moiety or to the coordination sphere of the pendant metal sites or by changing the identity of the metal atom(s). 13 The prevalent examples of such complexes are those bearing symmetrical (oligo)ethynylene 14,15 or polypyridyl bridging ligands. 16,17 It is our goal to synthesize discrete molecular components that can be assembled into multinuclear complexes via a coordination chemistry methodology, i.e., coordinating tectons. 18−20 Specifically we seek also to develop these tectons as asymmetric components in order to provide facile synthetic access to heterometallic complexes, and thus more readily elucidate and tune the effects of a particular metal site on the molecular properties of the complex as a whole. Our lab and others have reported on transition metal σ-alkynyl complexes derived from 5-ethynyl-2,2′-bipyridine and the successful κ 2 -N,N′-complexation of additional d-and f-block metals to the pendant diimine moiety. 19,21−28 We have previously reported the synthesis and characterization of the complexes [MCl(PP) 2 (CC{4,5-diazafluoren-9-yl})]PF 6 (M = Ru, Os; PP = dmpe, dppm, dppe; not all combinations), 18 and in this investigation we describe efforts to synthesize multinuclear complexes incorporating 1, Scheme 1. Recent developments in metallocumulene chemistry have been reported. 29 Contemporary with our investigations examples of the formation of bimetallic complexes by reaction of metal precursors with the closely related allenylidene

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Mixed‐Transition‐Metal Acetylides: Synthesis and Characterization of Complexes with up to Six Different Transition Metals Connected by Carbon‐Rich Bridging Units

Packheiser

Ecorchard

Rüffer

et al. 2008

Chemistry A European J

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The synthesis and reaction chemistry of heteromultimetallic transition-metal complexes by linking diverse metal-complex building blocks with multifunctional carbon-rich alkynyl-, benzene-, and bipyridyl-based bridging units is discussed. In context with this background, the preparation of [1-{(eta(2)-dppf)(eta(5)-C(5)H(5))RuC[triple bond]C}-3-{(tBu(2)bpy)(CO)(3)ReC[triple bond]C}-5-(PPh(2))C(6)H(3)] (10) (dppf = 1,1'-bis(diphenylphosphino)ferrocene; tBu(2)bpy = 4,4'-di-tert-butyl-2,2'-bipyridyl; Ph = phenyl) is described; this complex can react further, leading to the successful synthesis of heterometallic complexes of higher nuclearity. Heterotetrametallic transition-metal compounds were formed when 10 was reacted with [{(eta(5)-C(5)Me(5))RhCl(2)}(2)] (18), [(Et(2)S)(2)PtCl(2)] (20) or [(tht)AuC[triple bond]C-bpy] (24) (Me = methyl; Et = ethyl; tht = tetrahydrothiophene; bpy = 2,2'-bipyridyl-5-yl). Complexes [1-{(eta(2)-dppf)(eta(5)-C(5)H(5))RuC[triple bond]C}-3-{(tBu(2)bpy)(CO)(3)ReC[triple bond]C}-5-{PPh(2)RhCl(2)(eta(5)-C(5)Me(5))}C(6)H(3)] (19), [{1-[(eta(2)-dppf)(eta(5)-C(5)H(5))RuC[triple bond]C]-3-[(tBu(2)bpy)(CO)(3)ReC[triple bond]C]-5-(PPh(2))C(6)H(3)}(2)PtCl(2)] (21), and [1-{(eta(2)-dppf)(eta(5)-C(5)H(5))RuC[triple bond]C}-3-{(tBu(2)bpy)(CO)(3)ReC[triple bond]C}-5-{PPh(2)AuC[triple bond]C-bpy}C(6)H(3)] (25) were thereby obtained in good yield. After a prolonged time in solution, complex 25 undergoes a transmetallation reaction to produce [(tBu(2)bpy)(CO)(3)ReC[triple bond]C-bpy] (26). Moreover, the bipyridyl building block in 25 allowed the synthesis of Fe-Ru-Re-Au-Mo- (28) and Fe-Ru-Re-Au-Cu-Ti-based (30) assemblies on addition of [(nbd)Mo(CO)(4)] (27), (nbd = 1,5-norbornadiene), or [{[Ti](mu-sigma,pi-C[triple bond]CSiMe(3))(2)}Cu(N[triple bond]CMe)][PF(6)] (29) ([Ti] = (eta(5)-C(5)H(4)SiMe(3))(2)Ti) to 25. The identities of 5, 6, 8, 10-12, 14-16, 19, 21, 25, 26, 28, and 30 have been confirmed by elemental analysis and IR, (1)H, (13)C{(1)H}, and (31)P{(1)H} NMR spectroscopy. From selected samples ESI-TOF mass spectra were measured. The solid-state structures of 8, 12, 19 and 26 were additionally solved by single-crystal X-ray structure analysis, confirming the structural assignment made from spectroscopy.

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A first mixed heteropentametallic transition metal complex: Synthesis and characterisation

Cited by 26 publications

References 26 publications

Coordinating Tectons. Experimental and Computational Infrared Data as Tools To Identify Conformational Isomers and Explore Electronic Structures of 4-Ethynyl-2,2′-bipyridine Complexes

Coordinating Tectons. Experimental and Computational Infrared Data as Tools To Identify Conformational Isomers and Explore Electronic Structures of 4-Ethynyl-2,2′-bipyridine Complexes

Coordinating Tectons 4: Coordination Chemistry of the 4,5-Diazafluoren-9-yl Moiety as a Metallo-Ligand for Allenylidene Complexes

Mixed‐Transition‐Metal Acetylides: Synthesis and Characterization of Complexes with up to Six Different Transition Metals Connected by Carbon‐Rich Bridging Units

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