Solvent, coordination and hydrogen-bond effects on the chromic luminescence of the cationic complex [(phen)(H2O)Re(CO)3]+

Complexes of copper and 1,10-phenanthroline have been utilized for organic transformations over the last 50 years. In many cases these systems are impacted by reaction conditions and perform best under an inert atmosphere. Here we explore the role the 1,10-phenanthroline ligand plays on the electronic structure and redox properties of copper coordination complexes, and what benefit related ligands may provide to enhance copper-based coupling reactions. Copper(II) triflate complexes bearing 1,10-phenanthroline (phen), ([Cu(phen) 2 -(OTf )]OTf, 1) and oxidized derivatives of phen including [Cu(edhp) 2 ](OTf ) 2 (2), [Cu(pdo) 2 ](OTf ) 2 (3), [Cu(dafo) 2 ](OTf ) 2 (4) [a] Previously, we have reported a discrete Cu 2+ phen complex, namely [Cu(phen) 2 OTf ]OTf (1), [14] which shows a good reactivity performing C-and N-atom transfer reactions. [15] However, the phen ligand can be easily oxidized to functionalize the central ring of this ligand system. The C=C bond between C5 and C6 positions can be oxidized to form the 5,6-epoxyphen (L2) [16] and 5,6-phendione (L3). [17] L3 can be further reacted to form the 4,5-diazafluorenone (L4) by the loss of CO. [18] These ligands Full Paper

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“…, The O water –O triflate distance is ca. 2.70 and 2.73 Å, indicating the water is hydrogen bonded to the two triflate counterions …”

Section: Resultsmentioning

confidence: 96%

Tuning the Copper(II)/Copper(I) Redox Potential for More Robust Copper‐Catalyzed C–N Bond Forming Reactions

et al. 2020

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“…Also, the emission maxima do not show hypsochromic shift as observed for the monometallic related complex [(phen)(H2O)Re(CO)3] + (CF3SO3) -] [48]. Based on their extinction coefficients and the comparison with related complexes, they can be assigned to π(phen)  π*(phen) intraligand (IL) and Re(dπ) π*(phen) metal to ligand charge transfer (MLCT) transitions, respectively.…”

Section: Spectroscopic Properties In Solution Figure 4amentioning

confidence: 75%

“…It has been previously described that adventitious water may lead to rhenium-aquo species [48]. For [(phen)(H2O)Re(CO)3] + (CF3SO3) -, the triflate anion forms hydrogen bonds with the coordinated water molecule, moreover the hydrogen bonding capacity has been argued to influence the spectroscopy of the cation [48]. For the present case one would suppose that the aquo cation reacts with other rhenium(I) species present in solution to lead to the dimeric [(CO)3(phen)Re(µ-OH)Re(phen)(CO)3] + (1 + ) cation.…”

Section: Resultsmentioning

confidence: 99%

“…Based on their extinction coefficients and the comparison with related complexes, they can be assigned to π(phen)  π*(phen) intraligand (IL) and Re(dπ) π*(phen) metal to ligand charge transfer (MLCT) transitions, respectively. For 2 + the lowest energy band is also broad in DCM, being found to be around 375 nm [27], while for [(phen)(H2O)Re(CO)3] + (CF3SO3)it appears about 350 nm [48]. Figure 5 shows the TD-DFT computed spectra for 1 + (fully and partly optimized) and 1 + Br -, showing the main transitions.…”

Section: Spectroscopic Properties In Solution Figure 4amentioning

confidence: 98%

“…As stated for similar compounds, the emission has mainly MLCT character [27,45,48]. A very rough approximate calculation of the emission wavelengths can be made by DFT-optimizing the geometry of the molecule in the first triplet configuration (1 + (S=1)) and then using this for computing the vertical excitations by TD-DFT [49].…”

Section: Spectroscopic Properties In Solution Figure 4amentioning

confidence: 99%

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Do the bridging angle affect the luminescent properties of [(CO)3(phen)Re(µ-OH)Re(phen)(CO)3]+?. An experimental and computational study on three polymorphs

et al. 2019

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The reaction of [Re I Br(CO)3(THF)]2 with phenanthroline in solution leads to the diimine rhenium(I)tricarbonyl [(phen)Re(CO)3Br] and the dimer [(CO)3(phen)Re(µ-OH)(phen)Re(CO)3] + Br-(1 + Bras as a by-product (∼ 5% yield). This latter bimetallic compound crystallizes as a mixture of three polymorphs, with variable amount of solvent: 1 + Br-•CHCl3 (triclinic and orthorhombic) and 1 + Br-•2(CHCl3) (triclinic). Rietveld analysis showed 38, 54 and 8% of 1 + Br-•CHCl3 (triclinic), 1 + Br-•CHCl3 (orthorhombic) and 1 + Br-•2(CHCl3) (triclinic) respectively. The 1 + cation shows two [Re I (phen)(CO)3] + units connected by means of a central hydroxyl group. Noteworthy, the bridging Re−O−Re angle varies between 130.9(7)° to 140.7(2)° along the polymorphic series. UV-vis spectrum for the 1 + shows a broad absorption band around 390 nm in CH2Cl2 which has been attributed to has MLCT character (Re(dπ)→π*(phen)) as confirmed by DFT. Excitation at 405 nm in solution leads to emission at 595 nm (DCM), 605 nm (DMF) and 625 nm (CH3CN). The emission follows a mono-exponential law of decay and has lifetime of 405.8 ns (DCM). The solid-state polymorphic mixture absorbs around 460 nm. Excitation of the solid at 320 nm leads to emission with a maximum at 575 nm, which follow a bi-exponential law of decay with two components, a short one τ1 of 27.0 ns and longer one τ2 of 178.5 ns. These results suggest that the emitting state does not vary as function of the molecular geometry.

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An amine linker group modulates luminescent properties in a Rhenium(I) tricarbonyl complex. How can it be applied for ratiometric oxygen sensing?

et al. 2020

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Solvent, coordination and hydrogen-bond effects on the chromic luminescence of the cationic complex [(phen)(H₂O)Re(CO)₃]⁺

Abstract: The unusual behavior of the solution luminescence emission of [(phen)(H2O)Re(CO)3]+(CF3SO3)− depends on the solvent polarity, and coordinating and hydrogen bonding ability.

Cited by 11 publications

References 42 publications

Tuning the Copper(II)/Copper(I) Redox Potential for More Robust Copper‐Catalyzed C–N Bond Forming Reactions

Tuning the Copper(II)/Copper(I) Redox Potential for More Robust Copper‐Catalyzed C–N Bond Forming Reactions

Do the bridging angle affect the luminescent properties of [(CO)3(phen)Re(µ-OH)Re(phen)(CO)3]+?. An experimental and computational study on three polymorphs

An amine linker group modulates luminescent properties in a Rhenium(I) tricarbonyl complex. How can it be applied for ratiometric oxygen sensing?

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