A ruthenium(II) allenylidene complex with a 4,5-diazafluorene functional group: A new building-block for organometallic molecular assemblies

Pélerin, Olivier; Olivier, Céline; Roisnel, Thierry; Touchard, Daniel; Rigaut, Stéphane

doi:10.1016/j.jorganchem.2008.03.014

Cited by 17 publications

(14 citation statements)

References 57 publications

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“…In 6 interactions between phenyl rings of the dppm ligands and bpy ligands of the coordinated ruthenium center presumably destroy the chemical equivalence of the phosphorus nuclei, and an AA′BB′ spin system results. This same effect has previously been observed for the complexes [RuCl(dppm) 2 CCC(Me)(R)] + (R = Nphenothiazine or N-iminostilbene), 85 although a similar loss of symmetry is not reported for the dppe-ligated analogues of 6 reported by Peĺerin et al 30 In 7 the coordinated [RuCl(η 6 -pcymene)] + moiety is less sterically demanding than the tris(diimine) analogue, and only a singlet resonance is observed in the 31 P{ 1 H} NMR spectra, indicating that spatial interactions between the dppm and p-cymene ligands at the two different ruthenium centers are minimal.…”

Section: ■ Introductionsupporting

confidence: 82%

“…29 Contemporary with our investigations examples of the formation of bimetallic complexes by reaction of metal precursors with the closely related allenylidene complexes [RuCl(16-TMC)(CCC{2-py} 2 )]PF 6 and [RuCl(dppe) 2 (CC{4,5-diazafluoren-9-yl})]OTf have appeared. 30,31 However, our analogous reactions of 1 with metal precursors failed to afford isolable products. Instead, we were able to exploit the tritopic nature of the 9-hydroxy-9-ethynyl-4,5-diazafluorene proligand, L1, to afford multimetallic complexes by coordination of the diimine prior to formation of the allenylidene moiety.…”

Section: ■ Introductionmentioning

confidence: 91%

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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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Section: ■ Introductionsupporting

confidence: 82%

Section: ■ Introductionmentioning

confidence: 91%

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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“… The organic substituents on the allenylidene ligands were chosen to sample across a range of chemical space, including Selegue’s dimethylallenylidene ligand ([ 1a ]OTf), the electroneutral phenyl group ([ 1b ]OTf), and the cyclic alkyl fragment C 6 H 10 ([ 1c ]OTf), which was obtained as a mixture of the vinylidene and allenylidene species, consistent with prior observations (Schemes and ) . The ligands bearing the thioanisole ([ 1d ]OTf), thiophenyl ([ 1e ]OTf), and pyridyl ([ 1f ]OTf) groups capable of binding to metallic surfaces were also introduced with a view to later work with allenylidene-based molecular wires in molecular junctions, which will be reported elsewhere. ,− To demonstrate the generality of the reactions that follow, the representative half-sandwich complexes [Ru{CCC(Me)Ph}(dppe)Cp*]PF 6 ([ 2b ]PF 6 ) and [Ru{CCC(Me)(4-MeS-C 6 H 4 )}(dppe)Cp*]PF 6 ([ 2d ]PF 6 ) were also prepared from [RuCl(dppe)Cp*] and the respective propargylic alcohols B and D in the presence of NH 4 PF 6 .…”

Section: Resultsmentioning

confidence: 77%

Further Chemistry of Ruthenium Alkenyl Acetylide Complexes: Routes to Allenylidene Complexes via a Series of Electrophilic Addition Reactions

et al. 2020

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The methyl substituents in the cationic allenylidene complexes trans-[Ru{CCC(Me)R}Cl(dppe) 2 ]OTf ([1a−f]OTf) are readily deprotonated to give the corresponding alkenyl acetylide complexes trans-[Ru{CCC(CH 2 )R}Cl(dppe) 2 ] (3; R = Me (a), Ph (b), c C 5 H 10 (c), 4-MeS-C 6 H 4 (d), c C 4 H 3 S (e), c C 5 H 4 N (f)). Similar chemistry is also observed from [Ru{CCC(Me)Ph}(dppe)Cp*]-PF 6 ([2b]PF 6 ) and [Ru{CCC(Me)(4-MeS-C 6 H 4 )}(dppe)Cp*]-PF 6 ([2b]PF 6 ), chosen to broaden the reaction scope, giving [Ru{C CC(CH 2 )Ph}(dppe)Cp*] (4b) and [Ru{CCC(CH 2 )(4-MeS-C 6 H 4 )}(dppe)Cp*] (4d). In turn, reactions of 3b,d and 4b,d with the [BF 4 ] − salt of the electrophilic tritylium [CPh 3 ] + cation give the functionalized allenylidene complexes trans-[Ru{CCC(CH 2 CPh 3 )-R}Cl(dppe) 2 ]BF 4 ([5b,d]BF 4 ) and [Ru{CCC(CH 2 CPh 3 )R}(dppe)Cp*]BF 4 ([6b,d]BF 4 ) formed by addition of the electrophile to the remote vinylic carbon (C(δ)). Although trans-[Ru{CCC(CH 2 CPh 3 )Me}Cl(dppe) 2 ]BF 4 ([5a]BF 4 ) could not be successfully purified from reactions of 3a with [CPh 3 ]BF 4 , deprotonation of the crude product gave the Zaitsev vinyl product trans-[Ru{CCC(CHCPh 3 )Me}Cl(dppe) 2 ] (7a) in good yield. The initial cycloheptatrienyl adducts formed from reactions of 3b,d and 4b,d with the tropylium salt [C 7 H 7 ]BF 4 undergo a ring-contraction process in chloroform solutions upon exposure to air, to give the styrene-like products trans-[Ru{CCC(R)C(H)CHPh}Cl(dppe) 2 ]BF 4 ([10b,d]BF 4 ) and [Ru{CC C(R)C(H)CHPh}(dppe)Cp*]BF 4 ([11b,d]BF 4 ), through what is believed to be a radical mechanism mediated by triplet oxygen.

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“…In mono-allenylidene metal complexes the transition in the visible region possesses a metal-ligand charge transfer (MLCT) character of the type Ru II (dπ) → π*(allenylidene). [23] Similarly, the broad absorption observed for [Ru]1 and [Ru]2 in the visible is expected to arise from the allowed transition from one of the metal-based orbitals (HOMO) to the allenylidene-ligand-based LUMO.…”

Section: Resultsmentioning

confidence: 99%

Design and synthesis of novel organometallic dyes for NiO sensitization and photo-electrochemical applications

et al. 2016

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Two metallo-organic dyes were synthesized and used for NiO sensitization in view of their photoelectrochemical applications. The new dyes present an original π-conjugated structure containing the [Ru(dppe)2] metal fragment with a highly delocalized allenylidene ligand on one side and a σ-alkynyl ligand bearing an electron-rich group, i.e. a thiophene or triphenylamine unit, and one or two anchoring functions on the other side. The optoelectronic, electrochemical and photoelectrochemical properties of the dyes were systematically investigated. A broad photoresponse was observed with the absorption maximum at 600 nm. The X-ray crystal structure of one precursor was obtained to elucidate the structural conformation of the organometallic complexes and theoretical calculations were performed in order to address the photophysical properties of the new dyes. These photosensitizers were further implemented in NiO-based photocathodes and tested as photocurrent generators under pertinent aqueous conditions in association with [Co(NH3)5Cl]Cl2 as an irreversible electron acceptor. The dye-sensitized photocathodes provided good photocurrent densities (40 to 60 μA cm(-2)) at neutral pH in phosphate buffer and a high stability was observed for the two dyes.

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A ruthenium(II) allenylidene complex with a 4,5-diazafluorene functional group: A new building-block for organometallic molecular assemblies

Cited by 17 publications

References 57 publications

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

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

Further Chemistry of Ruthenium Alkenyl Acetylide Complexes: Routes to Allenylidene Complexes via a Series of Electrophilic Addition Reactions

Design and synthesis of novel organometallic dyes for NiO sensitization and photo-electrochemical applications

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