Long-lived photoluminescence from an eight-coordinate zirconium(<scp>iv</scp>) complex with four 2-(2′-pyridyl)pyrrolide ligands

Leary, Dylan C.; Martinez, Jordan C.; Ahkmedov, Novruz G; Petersen, Jeffrey L.; Milsmann, Carsten

doi:10.1039/d2cc04912k

Cited by 5 publications

(6 citation statements)

References 33 publications

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“…In the design of effective systems for harnessing and utilizing diffuse solar energy, it is imperative to understand where photoinduced charge-transfer states localize so that they can be extracted to provide electrons for productive redox chemistry. Recent elegant synthesis and spectroscopic studies have shown how to manipulate metal-to-ligand, ligand-to-metal, and ligand-centered charge-transfer states in coordination complexes based on earth-abundant, often first-row transition metals to dramatically extend excited-state lifetimes. − The work presented here complements these studies by providing a foundational understanding of the directionality of MLCT states in earth-abundant molecular photosensitizers, potentially circumventing the need for extremely long-lived excited states because the photogenerated electrons are exactly where they need to be. Here, we have shown that by adding common electron-donating or -withdrawing phenanthroline ligands, we can predictively direct the MLCT state to one ligand or another.…”

Section: Discussionmentioning

confidence: 88%

Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes

Wang,

Xie,

Phelan

et al. 2023

Inorg. Chem.

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A key challenge to the effective utilization of solar energy is to promote efficient photoinduced charge transfer, specifically avoiding unproductive, circuitous electron-transfer pathways and optimizing the kinetics of charge separation and recombination. We hypothesize that one way to address this challenge is to develop a fundamental understanding of how to initiate and control directional photoinduced charge transfer, particularly for earth-abundant first-row transition-metal coordination complexes, which typically suffer from relatively short excited-state lifetimes. Here, we report a series of functionalized heteroleptic copper(I)bis(phenanthroline) complexes, which have allowed us to investigate the directionality of intramolecular photoinduced metal-to-ligand charge transfer (MLCT) as a function of the substituent Hammett parameter. Ultrafast transient absorption suggests a complicated interplay of MLCT localization and solvent interaction with the Cu(II) center of the MLCT state. This work provides a set of design principles for directional charge transfer in earth-abundant complexes and can be used to efficiently design pathways for connecting the molecular modules to catalysts or electrodes and integration into systems for light-driven catalysis.

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Section: Discussionmentioning

confidence: 88%

Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes

Wang,

Xie,

Phelan

et al. 2023

Inorg. Chem.

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“…The development of photoactive metal complexes with earth-abundant metals holds great promise to enable sustainable photocatalysis, (solar) energy conversion, and light-emitting diodes (LEDs). − Hence, considerable efforts have been undertaken to explore this compound class in the recent years , with creative designs utilizing excited states of different characters like metal-to-ligand charge transfer (MLCT), ligand-to-metal charge transfer (LMCT), ligand-to-ligand charge transfer (LL’CT), and metal-centered (MC) states, , covering zirconium, − vanadium, − chromium, − iron, − manganese, − cobalt, , copper, − molybdenum, − and zinc as metal centers , among others.…”

Section: Introductionmentioning

confidence: 99%

Stable Molybdenum(0) Carbonyl Complex for Upconversion and Photoredox Catalysis

Kitzmann

Bertrams

Boden³

et al. 2023

J. Am. Chem. Soc.

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Photoactive complexes with earth-abundant metals have attracted increasing interest in the recent years fueled by the promise of sustainable photochemistry. However, sophisticated ligands with complicated syntheses are oftentimes required to enable photoactivity with nonprecious metals. Here, we combine a cheap metal with simple ligands to easily access a photoactive complex. Specifically, we synthesize the molybdenum(0) carbonyl complex Mo(CO)3(tpe) featuring the tripodal ligand 1,1,1-tris(pyrid-2-yl)ethane (tpe) in two steps with a high overall yield. The complex shows intense deep-red phosphorescence with excited state lifetimes of several hundred nanoseconds. Time-resolved infrared spectroscopy and laser flash photolysis reveal a triplet metal-to-ligand charge-transfer (3MLCT) state as the lowest excited state. Temperature-dependent luminescence complemented by density functional theory (DFT) calculations suggest thermal deactivation of the 3MLCT state via higher lying metal-centered states in analogy to the well-known photophysics of [Ru(bpy)3]2+. Importantly, we found that the title compound is very photostable due to the lack of labilized Mo–CO bonds (as caused by trans-coordinated CO) in the facial configuration of the ligands. Finally, we show the versatility of the molybdenum(0) complex in two applications: (1) green-to-blue photon upconversion via a triplet–triplet annihilation mechanism and (2) photoredox catalysis for a green-light-driven dehalogenation reaction. Overall, our results establish tripodal carbonyl complexes as a promising design strategy to access stable photoactive complexes of nonprecious metals avoiding tedious multistep syntheses.

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“…For an LMCT process to occur, rational selection of electron-deficient metal centers and linkers containing electron-rich functional groups is important. In this regard, on one hand, Zr(IV) with d 0 electronic configuration has recently gained attention in designing Earth-abundant photoluminescent transition-metal complexes. − This is due to the fact that Zr(IV) is highly electron deficient with no d–d electronic transitions. On the other hand, dihydrotetrazine functions are electron rich due to the presence of two imine −CN– and two −NH sites.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Roles of Dihydrotetrazine-Decorated Zr-MOFs in Photoluminescence and Colorimetrism for Discrimination of Arsenate and Phosphate Ions in Water

Razavi,

Habibzadeh,

Morsali

2023

ACS Appl. Mater. Interfaces

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The high chemical and structural stabilities of zirconium (Zr)-based metal-organic frameworks (MOFs) in aquatic media make them ideal candidates for wastewater treatment. Rational decoration or Zr-MOFs with functional groups can significantly extend their application in this area. In this work, two well-known Zr-MOFs, UiO-66 and MIL-140-A, were functionalized with dihydrotetrazine function to increase their capability in water treatment. Investigations reveal that these two dihydrotetrazine (DHTZ)-functionalized MOFs, namely UiO-66(Zr)-DHTZ and MIL-140(Zr)-DHTZ, can be applied as a twocomponent array for highly selective and sensitive discrimination of arsenate (AsO 4 3− ) and phosphate (PO 4 3− ) ions in water in the presence of other anions. Photoluminescence (PL) tests using UiO-66(Zr)-DHTZ show that this MOF can detect these two anions via a ratiometric response, 1.74 for arsenate and 1.84 for phosphate at 2 μM, with superior detection limits (7.2 × 10 −8 M for AsO 4 3− and 4.3 × 10 −8 M for PO 4 3−). The ratiometric PL response of UiO-66(Zr)-DHTZ toward arsenate and phosphate anions arises possibly from the arsenate-dihydrotetrazine hydrogen bonding. In the next step, colorimetric tests using MIL-140(Zr)-DHTZ were conducted to discriminate the arsenate from phosphate with a very low detection limit at nanomolar level. This MOF undergoes a yellow-to-pink color change in the presence of arsenate ions, while no color change is observed in the presence of phosphate. This color change is observed through conversion of dihydrotetrazine sites inside the pores of MIL-140(Zr)-DHTZ into tetrazine. Altogether, the PL response of UiO-66(Zr)-DHTZ is originated from the hydrogen bond-donating/accepting character of DHTZ function, while the colorimetric response of MIL-140(Zr)-DHTZ is based on the chemical conversion of DHTZ function. This work clearly shows that the decoration of Zr-based MOFs with multicharacter functional groups can develop their application in wastewater treatment as multipurpose platforms.

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Long-lived photoluminescence from an eight-coordinate zirconium(iv) complex with four 2-(2′-pyridyl)pyrrolide ligands

Abstract: The photoluminescent eight-coordinate zirconium complex Zr(HPMPH)4 supported by four monoanionic 2-(2’-pyridine)pyrrolide ligands was synthesized. This molecule shows dual emission via fluorescence and phosphorescence with an overall quantum efficiency of 4%...

Cited by 5 publications

References 33 publications

Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes

Changing Directions: Influence of Ligand Electronics on the Directionality and Kinetics of Photoinduced Charge Transfer in Cu(I)Diimine Complexes

Stable Molybdenum(0) Carbonyl Complex for Upconversion and Photoredox Catalysis

Multifunctional Roles of Dihydrotetrazine-Decorated Zr-MOFs in Photoluminescence and Colorimetrism for Discrimination of Arsenate and Phosphate Ions in Water

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