New Synthetic Routes to Cationic Rhenium Tricarbonyl Bipyridine Complexes with Labile Ligands

Hevia, Eva; Pérez, Julio; Riera, Vı́ctor; Miguel, Daniel; Kassel, W. Scott; Rheingold, Arnold L.

doi:10.1021/ic020174c

Cited by 53 publications

(49 citation statements)

References 45 publications

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“…The ligandsw ere purifiedb yr ecrystallization from ethanol and fully characterisedb yc ommon methods. The reaction of Re(CO) 5 Cl with L 1 and L 2 in toluene at 110 8Cy ieldedt he desired mononuclearR ec ompounds 1 and 2,r espectively,a sy ellow powders, which were further purified by washing with hexane and Et 2 O. Mass spectrometry confirmed the formation of the desired complexes and elemental analysistheir purity.X -ray structures confirmed the proposed structure.…”

Section: Complex Synthesis and Characterisationmentioning

confidence: 90%

“…[3] Lehn and co-workers have introduced the a-diimine-Re(CO) 3 catalystf amily as very efficient electro-and photocatalystsf or the selective CO 2 -to-CO conversion. [4,5] Research on [Re(CO) 3 (bpy)Cl], I (bpy = 2,2'-bipyrdine, Figure 1), has led to ad etailedp ictureo f the electrocatalytic cycle. [6] Ther eactionp roceeds either through the one-or the two-electron pathway (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

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Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis

Wilting

Siewert

2019

Chemistry A European J

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Here, the reduction chemistry of mono-and binuclear a-diimine-Re(CO) 3 complexes with proton responsive ligands and their application in the electrochemically-driven CO 2 reduction catalysis are presented. The work was aimed to investigate the impact of 1) two metal ions in close proximity and 2) an internal proton source on catalysis. Therefore, three different Re complexes,abinuclear one with a central phenol unit, 3,a nd two mononuclear,o ne having a central phenol unit, 1,a nd one with am ethoxy unit, 2,w ere utilised. All complexes are active in the CO 2 -to-CO conversion and CO is always the major product. The catalytic rate constant k cat for all three complexes is much highera nd the overpotential is lower in DMF/water mixturest han in pure DMF (DMF = N,N-dimethylformamide). Cyclic voltammetry (CV) studies in the absence of substrate revealed that this is due to an acceleratedc hloride ion loss after initial reduction in DMF/water mixtures in comparison to pure DMF.C hloride ion loss is necessaryf or subsequentC O 2 binding and this step is around ten times faster in the presence of water [2:k Cl (DMF) % 1.7 s À1 ; k Cl (DMF/H 2 O) % 20 s À1 ]. The binuclear complex 3 with ap roton responsive phenol unit is more active than the mononuclear complexes. In the presence of water, the observed rate constant k obs for 3 is four times higher than of 2,i nt he absence of water even ten times. Thus,t he two metal centres are beneficial for catalysis.L astly,t he investigation showedt hat the phenol unit has no impacto n the rate of the catalysis, it even slows down the CO 2 -to-CO conversion.T his is due to an unproductive,c ompetitive side reaction: After initial reduction, 1 and 3 loose either Cl À or undergo ar eductive OH deprotonation forming ap henolate unit. The phenolate could bind to the metal centre blocking the sixth coordination site for CO 2 activation. In DMF,O ÀH bond breaking andC l À ion loss have similar rate constants [1: k Cl (DMF) % 2s À1 , k OH % 1.5 s À1 ], in water/DMF Cl À loss is much faster.T hus, the effect on the catalytic rate is more pronounced in DMF.H owever,t he acidic protons lower the overpotential of the catalysis by about 150 mV.

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Section: Complex Synthesis and Characterisationmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis

Wilting

Siewert

2019

Chemistry A European J

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“…[25] Unlike these complexes, 3 is not labile. For instance, it is unreactive towards PMe 3 or pyridine.…”

Section: (Bipy)]mentioning

confidence: 98%

Reactivity of Molybdenum and Rhenium Hydroxo‐Carbonyl Complexes toward Organic Electrophiles

Cuesta

Gerbino

Hevia

et al. 2004

Chemistry A European J

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The hydroxo compounds [Re(OH)(CO)(3)(N-N)] (N-N=bipy, 2 a; Me(2)-bipy, 2 b) were prepared in a biphasic H(2)O/CH(2)Cl(2) medium by reaction of [Re(OTf)(CO)(3)(N-N)] with KOH. In contrast, when anhydrous CH(2)Cl(2) was used, the binuclear hydroxo-bridged compound [[Re(CO)(3)(bipy)](2)(mu-OH)]OTf (3-OTf) was obtained. Compound [Re(OH)(CO)(3)(Me(2)-bipy)] (2 b) reacted with phenyl acetate or vinyl acetate to afford [Re(OAc)(CO)(3)(Me(2)-bipy)] (4) and phenol or acetaldehyde, respectively. The reactions of [Mo(OH)(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (1), 2 a, and 2 b toward several unsaturated organic electrophiles were studied. The reaction of 1 with (p-tolyl)isocyanate afforded an adduct of N,N'-di(p-tolyl)urea and the carbonato-bridged compound [[Mo(eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)](2)(mu-eta(1)(O),eta(1)(O)-CO(3))] (5). In contrast, the reaction of 2 a with phenylisocyanate afforded [Re(OC(O)NHPh)(CO)(3)(bipy)] (6); this results from formal PhNCO insertion into the O-H bond. On the other hand, compounds [Mo[SC(O)NH(p-tolyl)](eta(3)-C(3)H(4)-Me-2)(CO)(2)(phen)] (7), [Re[SC(O)NH(p-tolyl)](CO)(3)(Me(2)-bipy)] (8 a), and [Re[SC(O)NHEt](CO)(3)(Me(2)-bipy)] (8 b) were obtained by reaction of 1 or 2 b with the corresponding alkyl or aryl isothiocyanates. In those cases, RNCS was inserted into the M-O bond. The reactions of 1, 2 a, and 2 b with dimethylacetylenedicarboxylate (DMAD) gave the complexes [Mo[C(OH)-C(CO(2)Me)C(CO(2)Me)-O](eta(3)-C(3)H(4)-Me-2)(CO)(phen)] (9) and [Re[C(OH)C(CO(2)Me)C(CO(2)Me)O](CO)(2)(N-N)] (N-N=bipy, 10 a; Me(2)-bipy, 10 b). The molecules of these compounds contain five-membered metallacycles that are the result of coupling between the hydroxo ligand, DMAD, and one of the CO ligands. The new compounds were characterized by a combination of IR and NMR spectroscopy, and for [[Re(CO)(3)(bipy)(2)(mu-OH)]BF(4) (3-BF(4)), 4, 5, 6, 7, 8 b, 9, and 10 b, also by means of single-crystal X-ray diffraction.

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“…Treatment of EG-S-ReCl with silver triflate in CHCl 3 at reflux 21,22 and subsequent addition of 1H-5-phenyltetrazole and triethylamine 12 led to the formation of EG-S-ReTPh in a 17% yield.…”

Section: Synthesis and Functionalisation Of The Complexesmentioning

confidence: 99%

Rhenium tetrazolato complexes coordinated to thioalkyl-functionalised phenanthroline ligands: synthesis, photophysical characterisation, and incubation in live HeLa cells

et al. 2015

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Three new complexes of formulation fac-[Re(CO) 3 (diim)L], where diim is either 1,10-phenanthroline or 1,10-phenanthroline functionalised at position 5 by a thioalkyl chain, and L is either a chloro or aryltetrazolato ancillary ligand, were synthesised and photophysically characterised. The complexes exhibit phosphorescent emission with maxima around 600 nm, originating from triplet metal-to-ligand charge transfer states with partially mixed ligand-to-ligand charge transfer character. The emission is relatively long-lived, within the 200-400 ns range, and with quantum yields of 2-4%. The complexes were trialed as cellular markers in live HeLa cells, along with two previously reported rhenium tetrazolato complexes bound to unsubstituted 1,10-phenanthroline. All five complexes exhibit good cellular uptake and non-specific perinuclear localisation. Upon excitation at 405 nm, the emission from the rhenium complexes could be clearly distinguished from autofluorescence, as demonstrated by spectral detection within the live cells.Four of the complexes did not appear to be toxic, however prolonged excitation could result in membrane blebbing. No major sign of photobleaching was detected upon multiple imaging on the same cell sample.2

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New Synthetic Routes to Cationic Rhenium Tricarbonyl Bipyridine Complexes with Labile Ligands

Cited by 53 publications

References 45 publications

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis

Reactivity of Molybdenum and Rhenium Hydroxo‐Carbonyl Complexes toward Organic Electrophiles

Rhenium tetrazolato complexes coordinated to thioalkyl-functionalised phenanthroline ligands: synthesis, photophysical characterisation, and incubation in live HeLa cells

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New Synthetic Routes to Cationic Rhenium Tricarbonyl Bipyridine Complexes with Labile Ligands

Cited by 53 publications

References 45 publications

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)3 Complexes with Proton‐Responsive Ligands in CO2 Reduction Catalysis

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)3 Complexes with Proton‐Responsive Ligands in CO2 Reduction Catalysis

Reactivity of Molybdenum and Rhenium Hydroxo‐Carbonyl Complexes toward Organic Electrophiles

Rhenium tetrazolato complexes coordinated to thioalkyl-functionalised phenanthroline ligands: synthesis, photophysical characterisation, and incubation in live HeLa cells

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Product

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Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis

Are Two Metal Ions Better than One? Mono‐ and Binuclear α‐Diimine‐Re(CO)₃ Complexes with Proton‐Responsive Ligands in CO₂ Reduction Catalysis