Non-innocent ligand reservoirs for reducing or oxidizing equivalents in carbonylrhenium(I) complexes: 1,1′-Bis(diphenylphosphino)ferrocene (dppf) and bis-triazinyl-pyridine (BTP)

Roy, Sayak; Blane, Travis; Lilio, Alyssia M.; Kubiak, Clifford P.

doi:10.1016/j.ica.2011.02.005

Cited by 14 publications

(7 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, recent work has shown that non-innocent ligand reservoirs can significantly alter metal-ligand bonding in fac -Re I (CO) 3 complexes. 44 As such, the ability of the BODIPY appended ligand of [Re(BB2)(CO) 3 Cl] to store multiple reducing equivalents during electrocatalysis may manifest in enhanced nucleophilic character at the metal center, while providing an electron reservoir that helps to drive the two electron reduction of CO 2 to CO.…”

Section: Resultsmentioning

confidence: 99%

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

et al. 2014

View full text Add to dashboard Cite

The reduction of carbon dioxide to chemical fuels such as carbon monoxide is an important challenge in the field of renewable energy conversion. Given the thermodynamic stability of carbon dioxide, it is difficult to efficiently activate this substrate in a selective fashion and the development of new electrocatalysts for CO2 reduction is of prime importance. To this end, we have prepared and studied a new fac-ReI(CO)3 complex supported by a bipyridine ligand containing ancillary BODIPY moieties ([Re(BB2)(CO)3Cl]). Voltammetry experiments revealed that this system displays a rich redox chemistry under N2, as [Re(BB2)(CO)3Cl] can be reduced by up to four electrons at modest potentials. These redox events have been characterized as the ReI/0 couple, and three ligand based reductions – two of which are localized on the BODIPY units. The ability of the BB2 ligand to serve as a non-innocent redox reservoir is manifest in an enhanced electrocatalysis with CO2 as compared to an unsubstituted Re-bipyridine complex lacking BODIPY units ([Re(bpy)(CO)3Cl]). The second order rate constant for reduction of CO2 by [Re(BB2)(CO)3Cl] was measured to be k = 3400 M−1s−1 at an applied potential of −2.0 V versus SCE, which is roughly three times greater than the corresponding unsubstituted Re-bipyridine homologue. Photophysical and photochemical studies were also carried out to determine if [Re(BB2)(CO)3Cl] was a competent platform for CO2 reduction using visible light. These experiments showed that this complex supports unusual excited state dynamics that precludes efficient CO2 reduction and are distinct from those that are typically observed for fac-ReI(CO)3 complexes.

show abstract

Section: Resultsmentioning

confidence: 99%

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The discovery of ferrocene gave impetus to the development of metallocene chemistry . The increasing interest in ferrocene and its derivatives stems from their wide application in catalysis, the design of molecular magnets and devices, molecular electronics, nonlinear optical materials, electrochemical agents, and as donor ligands in coordination chemistry …”

Section: Introductionmentioning

confidence: 99%

Tin(IV) and Antimony(V) Complexes Bearing Catecholate Ligands Connected to Ferrocene – Syntheses, Molecular Structures, and Electrochemical Properties

et al. 2016

View full text Add to dashboard Cite

The ferrocenyl‐containing 3,5‐di‐tert‐butylcatechol Fc‐L‐CatH2 (2) was synthesized by the condensation of the precursor 6‐(hydrazonomethyl)‐3,5‐di‐tert‐butylcatechol 6‐(H2N–N=CH)CatH2 (1) with ferrocenecarboxaldehyde (L = –CH=N–N=CH–, Cat = 3,5‐di‐tert‐butylcatecholate, Fc = ferrocene). The exchange reaction between catechol 2 and Ph3SbBr2 in the presence of a base (Et3N) in toluene leads to the formation of the triphenylantimony(V) catecholate (Fc‐L‐Cat)SbPh3 (3) as the main product and the ionic bromotriphenylantimony(V) catecholate (Fc‐LH‐Cat)SbPh3Br (4) containing a hydraziniumylidene cation (LH = –CH=NH+–N=CH–) as the byproduct. The change of toluene to tetrahydrofuran (THF) results in the formation of 4 as the main product in nearly quantitative yield. The exchange reactions of catechol 2 with Ph2SnCl2 and SnCl4 give anionic catecholate complexes bridged with hydraziniumylidene cations even in the presence of excess base. Complexes (Fc‐LH‐Cat)SnPh2Cl (5), (Fc‐LH‐Cat)2SnPh2 (6), and (Fc‐LH‐Cat)2SnCl2 (7) were synthesized. The compounds obtained were characterized by IR spectroscopy, 1H and 13C NMR spectroscopy, elemental analysis, and cyclic voltammetry. The molecular structures of crystals of 5–7 were determined by X‐ray diffraction analysis. The formation of catecholates 4–7 with hydraziniumylidene cations is caused by intramolecular hydrogen bonding between the hydroxy and imine groups, which leads to proton transfer from the oxygen atom to the nitrogen atom of the hydrazine linker.

show abstract

“…More recently, an impressive body of Re-based catalysis has been put forth by Kubiak, ,− Ishitani, − and recently by Nippe and Angeles-Boza, among many others. − These systems share themes of the use of a tricarbonyl-diimine coordination sphere and covalent modifications to the bpy backbone as a means to tune physicochemical properties. A second modification route is to substitute the X-type halide with an L-type phosphine ligand, which reduces the tendency for these complexes to dimerize to [Re(bpy)(CO) 3 ] 2 during the catalytic cycle. , These modifications have provided a deeper mechanistic understanding of CO 2 reduction; however, accessing more complex pendant groups on the bipyridyl ligand for further tuning requires multistep syntheses which are often low yielding and require demanding purifications. , Exchanging the bpy ligand for a more modular platform such as an oxazoline ligand provided excellent catalytic activity with ( i cat / i p ) values as high as 85, although there was a marked loss in Faradaic efficiency for CO production during controlled potential electrolysis experiments (55%) .…”

Section: Introductionmentioning

confidence: 99%

Rhenium(I) Phosphazane Complexes for Electrocatalytic CO₂ Reduction

et al. 2019

View full text Add to dashboard Cite

A library of 11 rhenium phosphazane complexes was synthesized and characterized for fundamental studies of electrochemical CO2 reduction. Because they contain chelating phosphorus donors, these complexes prevent deleterious dimerization of the precatalyst similarly to their monodentate analogues. These chelating species open a coordination site without complete ligand loss, which is hypothesized to increase catalyst longevity. Furthermore, the phosphazane ligands provided sites for synthetic modifications to control electronic structure, steric bulk, and install hydrogen bond donors. The effects of these parameters on the formation of CO from CO2 were investigated in the context of Faradaic efficiencies, catalytic current responses (i cat/i p), and catalyst longevity. Full structural characterization provided insight into the differences in catalytic performance between the complexes, including a dirhenium variant. Re(PNP H )(bpy)(CO)2OTf (bpy = 2,2′-bipyridine, PNP H = (Ph)2PNHP(Ph)2) showed high catalytic performance with an (i cat/i p)2 value of 795 and was active for >24 h with a 94% Faradaic efficiency. This library of electrocatalysts establishes a new class of tunable Re complexes from which a deeper mechanistic understanding of the CO2 reduction reaction emerges and underscores the efficacy of exploiting ligand-based participation in catalytic processes.

show abstract

Non-innocent ligand reservoirs for reducing or oxidizing equivalents in carbonylrhenium(I) complexes: 1,1′-Bis(diphenylphosphino)ferrocene (dppf) and bis-triazinyl-pyridine (BTP)

Cited by 14 publications

References 26 publications

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

Tin(IV) and Antimony(V) Complexes Bearing Catecholate Ligands Connected to Ferrocene – Syntheses, Molecular Structures, and Electrochemical Properties

Rhenium(I) Phosphazane Complexes for Electrocatalytic CO₂ Reduction

Contact Info

Product

Resources

About

Non-innocent ligand reservoirs for reducing or oxidizing equivalents in carbonylrhenium(I) complexes: 1,1′-Bis(diphenylphosphino)ferrocene (dppf) and bis-triazinyl-pyridine (BTP)

Cited by 14 publications

References 26 publications

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

Reduction of CO2 using a rhenium bipyridine complex containing ancillary BODIPY moieties

Tin(IV) and Antimony(V) Complexes Bearing Catecholate Ligands Connected to Ferrocene – Syntheses, Molecular Structures, and Electrochemical Properties

Rhenium(I) Phosphazane Complexes for Electrocatalytic CO2 Reduction

Contact Info

Product

Resources

About

Rhenium(I) Phosphazane Complexes for Electrocatalytic CO₂ Reduction