Photoactivated Functionizable Tetracarbonyl(phenylpyridine)manganese(I) Complexes as CO‐Releasing Molecules: A Direct Suzuki–Miyaura Cross‐Coupling on a Thermally Stable CO‐RM

Ward, Jonathan S.; Bray, Joshua T. W.; Aucott, Benjamin J.; Wagner, Conrad; Pridmore, Natalie E.; Whitwood, Adrian C.; Moir, James; Lynam, Jason M.; Fairlamb, Ian J. S.

doi:10.1002/ejic.201600775

Cited by 12 publications

(11 citation statements)

References 52 publications

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“…425–325 nm. On the basis of previous results, − irradiation within this wavelength range is known to result in CO loss. DFT was employed to rationalize the observed spectra.…”

Section: Resultsmentioning

confidence: 69%

“…Complex [ 1a ] was first described by Bruce in 1975 and is readily prepared from the reaction of 2-phenylpyridine with [Mn(CH 2 Ph)(CO) 5 ] . In previous studies, we have shown that [ 1a ], and its derivatives with modified 2-phenylpyridine groups (Figure ), act as photochemically activated CO-releasing molecules (photoCO-RMs). − Irradiation (λ = 400 nm) results in loss of up to three CO ligands as measured by the conversion of deoxymyoglobin to carboxymyoglobin. Furthermore, time-resolved spectroscopy has demonstrated that photolysis (λ = 355 nm) of [ 1a ] in the presence of catalytically relevant substrates such as alkynes, alkenes, and isocyanates can be used to initiate CO loss and observe the subsequent states involved in the C–C bond formation event which underpins Mn-catalyzed reactions .…”

Section: Resultsmentioning

confidence: 99%

“…Hence, we have been able to employ TRIR spectroscopy to garner structural information about this interconversion that cannot be obtained by TA. Given the role of complexes related to [ 1a ] as versatile CO-RMs − and in Mn-catalyzed C-H functionalization reactions, ,,, we anticipate that further TRIR studies will provide vital insight into their behavior. Importantly, when [ 1a ] is photolyzed in neat alkynes, alkenes, and isocyanates, kinetically controlled coordination (as shown for ethers and DMSO) also occurs.…”

Section: Discussionmentioning

confidence: 99%

“…In this paper, we demonstrate how [Mn(ppy)(CO) 4 ], [ 1a ], can be used as a highly effective probe for the nature of metal–solvent interactions and also the ultrafast dynamics of the solvation event. Such information is of considerable importance due to the role played by [ 1a ] (and its structural analogues) as photochemically activated therapeutic CO-releasing molecules − and also as intermediates in manganese-catalyzed C–H bond functionalization reactions. − The loss of a CO ligand from [ 1a ] underpins both applications and therefore gaining a detailed understanding of this event, and the subsequent solvation will provide fundamental insight into these applications. We now show that photochemically induced CO dissociation from [ 1a ] occurs in under 1 ps and the sensitivity of the changes to the frequency of the CO stretch modes in the resulting spectra allows for the nature of the solvent binding mode and subsequent dynamics to be determined.…”

Section: Introductionmentioning

confidence: 99%

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Manganese Carbonyl Compounds Reveal Ultrafast Metal–Solvent Interactions

et al. 2019

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Herein, we exemplify that time-resolved multipleprobe spectroscopy (TR M PS) with infrared detection can be used to observe and quantify the dynamic processes occurring during the solvation of a catalytically competent manganese(I) carbonyl compound. TR M PS has been used to demonstrate that a manganese(I) 2-phenylpyridyl (ppy) complex, [Mn(ppy)-(CO) 4 ], undergoes photochemically induced loss of a carbonyl ligand on a sub-picosecond time scale to give solvent (S) complexes of the type, fac-[Mn(ppy and DMSO). An excited state, assigned as 3 [Mn(ppy)(CO) 4 ], with a lifetime, τ, of ca. 5 ps is also formed as a minor photoproduct. The vibrational modes of the carbonyl ligands in fac-[Mn(ppy)-(S)(CO) 3 ] are diagnostic of the nature of the coordinated solvent and allow for the dynamics of solvation within the coordination of the metal to be observed. For example, in the case of THF, initial interactions with the metal occur through a C−H σ-interaction, assigned based on the similarity to the bands observed for the related heptane metal complex. Isomerization to the thermodynamically preferred O-binding mode was observed, τ ca. 18 ps, with similar behavior evident in 1,4-dioxane and n Bu 2 O. The lifetime for the isomerization shows a correlation with the number of C−H bonds in the solvent. In 1,4-dioxane, there is no evidence for the initial formation of an O-bound complex which indicates that the solvent binding is not stochastic in nature and is likely determined by the topology of the first solvation shell of the metal complex. The insight into these ultrafast metal−solvent interactions is enabled by the dominant photoprocess, CO dissociation, being rapid (<1 ps). Which, taken together with prompt vibrational cooling, enables the subtle interplay between metal and solvent during the solvation event to be characterized and quantified.

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“…425–325 nm. On the basis of previous results, − irradiation within this wavelength range is known to result in CO loss. DFT was employed to rationalize the observed spectra.…”

Section: Resultsmentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Manganese Carbonyl Compounds Reveal Ultrafast Metal–Solvent Interactions

et al. 2019

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“…The reactions given in Scheme are both believed to involve manganacycle 4 . , We identified that the use of real-time infrared spectroscopic analysis (in situ IR on the second time scale), in operando, is useful for probing the different manganese carbonyl species formed during the C–H bond activation reactions, yielding qualitative information about manganese carbonyl speciation and quantitative kinetic data. Use of IR spectroscopic analysis for studying transient manganese carbonyl species has been validated in our previous studies . For this mechanistic study, a Mettler-Toledo ReactIR instrument (IC10) with a Si probe was used (1 min scans, ± 4 cm –1 ) to monitor changes in the manganese carbonyl IR bands in real time.…”

Section: Resultsmentioning

confidence: 99%

Mechanistic Insight into Catalytic Redox-Neutral C–H Bond Activation Involving Manganese(I) Carbonyls: Catalyst Activation, Turnover, and Deactivation Pathways Reveal an Intricate Network of Steps

et al. 2019

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Manganese(I) carbonyl-catalyzed C−H bond functionalization of 2-phenylpyridine and related compounds containing suitable metal directing groups has recently emerged as a potentially useful synthetic methodology for the introduction of various groups to the ortho position of a benzene ring. Preliminary mechanistic studies have highlighted that these reactions could proceed via numerous different species and steps and, moreover, potentially different catalytic cycles. The primary requirement for typically 10 mol % catalyst, oftentimes the ubiquitous precursor catalyst, BrMn(CO) 5 , has not yet been questioned nor significantly improved upon, suggesting catalytic deactivation may be a serious issue to be understood and resolved. Several critical questions are further raised by the species responsible for providing a source of protons in the protonation of vinyl−manganese(I) carbonyl intermediates. In this study, using a combination of experimental and theoretical methods, we provide comprehensive answers to the key mechanistic questions concerning the Mn(I) carbonyl-catalyzed C−H bond functionalization of 2-phenylpyridine and related compounds. Our results enable the explanation of alkyne substrate dependencies, i.e., internal versus terminal alkynes. We found that there are different catalyst activation pathways for BrMn(CO) 5 , e.g., terminal alkynes lead to the generation of Mn I −acetylide species, whose formation is reminiscent of Cu I −acetylide species proposed to be of critical importance in Sonogashira cross-coupling processes. We have unequivocally established that alkyne, 2-phenylpyridine, and water can facilitate hydrogen transfer in the protonation step, leading to the liberation of protonated alkene products.

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Investigation of the CO releasing ability of azachalcone bound Mn(I) tricarbonyl complexes and their antiproliferative properties

Thomas

Kuduvalli

et al. 2022

Applied Organom Chemis

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A series of [Mn(CO)3(L)Br] complexes (1–5) are synthesized using azachalcones as ligands, wherein they are coordinated to the manganese metal through the nitrogen and oxygen donor atoms. Their characterization using various spectroscopic techniques, stability analysis in dimethyl sulfoxide solvent, photodecomposition analysis, and antiproliferative effect are reported herein. These complexes release CO upon exposure to green light radiation. DFT and TD‐DFT investigations are also reported to gather information regarding the electronic features of these complexes.

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Photoactivated Functionizable Tetracarbonyl(phenylpyridine)manganese(I) Complexes as CO‐Releasing Molecules: A Direct Suzuki–Miyaura Cross‐Coupling on a Thermally Stable CO‐RM

Cited by 12 publications

References 52 publications

Manganese Carbonyl Compounds Reveal Ultrafast Metal–Solvent Interactions

Manganese Carbonyl Compounds Reveal Ultrafast Metal–Solvent Interactions

Mechanistic Insight into Catalytic Redox-Neutral C–H Bond Activation Involving Manganese(I) Carbonyls: Catalyst Activation, Turnover, and Deactivation Pathways Reveal an Intricate Network of Steps

Investigation of the CO releasing ability of azachalcone bound Mn(I) tricarbonyl complexes and their antiproliferative properties

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