Controlling Near-Infrared Chromophore Electronic Properties through Metal–Ligand Orbital Alignment

Mews, Nicole M.; Berkefeld, Andreas; Hörner, Gerald; Schubert, Hartmut

doi:10.1021/jacs.6b13085

Cited by 15 publications

(33 citation statements)

References 61 publications

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“…Information on the purification of reagents and solvents, and preparation of new proligands B/C 0 -OPiv is provided in the Supporting Information. The following reagents and starting materials were prepared according to reported procedures: 1,1′-Bis(acetyl)ferrocenium bis(trifluoromethanesulfonyl)imide, [Fc″]NTf 2 , tris(4-bromophenyl)aminium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate, [(4-BrC 6 H 4 ) 3 N]BAr F 4 , 5- tert -butyl-2-methoxyphenyllithium, NaN(SiMe 3 ) 2 , KC 7 H 7 , 2,6-(2,4,6- i Pr 3 C 6 H 2 ) 2 C 6 H 3 SH, Tip 2 ArSH, A Ni -OPiv, A–O/A Ni -NTMS 2 , and [{ A–O Ni -thf} 2 (μ-Tf)]OTf [Tf = κ-O,O′–F 3 CSO 2 – , OTf = F 3 CSO 3 – ].…”

Section: Methodsmentioning

confidence: 99%

“…Information on the purification of reagents and solvents, and preparation of new proligands B/C 0-OPiv is provided in the Supporting Information. The following reagents and starting materials were prepared according to reported procedures: 1,1′-Bis(acetyl)ferrocenium bis(trifluoromethanesulfonyl)imide, 53 Preparation of A Ni-SArTip 2 . Addition of OEt 2 (10 mL) to a mixture of colorless Tip 2 ArSK, obtained from Tip 2 ArSH (55 mg, 0.106 mmol) and KC 7 H 8 (14 mg, 0.11 mmol) in toluene (2 g), and brick-red A Ni-OPiv (50 mg, 0.11 mmol) afforded a dark green solution immediately upon stirring.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms

et al. 2021

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This work reports on complex chromophores of planar nickel(II) of the general formula [(κ 3 -N,N′,C/O)Ni−ER], which combines a κ 2 -N,N′-coordinate aromatic N-heterocycle with a pendant phenyl/phenol donor and the variable coligands ER (= carboxylato, phenolato, amido, and arylthiolato). The absorption properties of the planar complex chromophores vary broadly depending on the interplay of the three constituting components. Increasing the manifold of π*-orbitals at the N-heterocyclic moiety through π-extension along 1,10-phenanthroline, tetrahydrodipyridophenazine, and dipyridophenazine has only a small impact on the energies of charge transfer type transitions across the visible (vis) to near-infrared (NIR) spectral region and is due to an inversion among spatially distinct but energetically close unoccupied molecular orbitals. Substantial absorptivity across the visible spectral region rather associates with the increasing capability among carboxylato, phenolato, amido, and arylthiolato coligands to engage in Ni−O/N/S π-bonding. This adds a mechanism for electronic coupling of coligand RE − and π*-orbitals at the Nheterocycle fragment through occupied d orbitals at nickel, enabling light-induced charge transfer. Aryl-S − performs best in this regard, but {Ni−O/N/S}-to-(N-heterocycle-π*) charge transfer efficacy depends on donor−acceptor orbital alignment and appears to be kinetically hindered except for amido coligands owing to polar effects. Irrespective of the nature of coligand RE − , the choice of the pendant phenyl/phenol side arm rules overall absorptivity by setting the energy of occupied frontier molecular orbitals.

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Section: Methodsmentioning

confidence: 99%

“…Information on the purification of reagents and solvents, and preparation of new proligands B/C 0-OPiv is provided in the Supporting Information. The following reagents and starting materials were prepared according to reported procedures: 1,1′-Bis(acetyl)ferrocenium bis(trifluoromethanesulfonyl)imide, 53 Preparation of A Ni-SArTip 2 . Addition of OEt 2 (10 mL) to a mixture of colorless Tip 2 ArSK, obtained from Tip 2 ArSH (55 mg, 0.106 mmol) and KC 7 H 8 (14 mg, 0.11 mmol) in toluene (2 g), and brick-red A Ni-OPiv (50 mg, 0.11 mmol) afforded a dark green solution immediately upon stirring.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms

et al. 2021

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“…All manipulations of air-and moisture-sensitive compounds were carried out under an atmosphere of dry argon using standard Schlenk or glove box techniques. Literature procedures were followed for the preparation of (Ph 3 P) 2 NiN(SiMe 3 ) 2 , ferrocenium salts, and thiophenol ligands [24,26,27]. General information on the purification of solvents and other reagents is provided in Supplementary Material.…”

Section: Methodsmentioning

confidence: 99%

Understanding Factors that Control the Structural (Dis)Assembly of Sulphur-Bridged Bimetallic Sites

et al. 2019

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Bimetallic structures of the general type [M2(µ-S)2] are omnipresent in nature, for biological function [M2(µ-S)2] sites interconvert between electronically distinct, but isostructural, forms. Different from structure-function relationships, the current understanding of the mechanism of formation and persistence of [M2(µ-S)2] sites is poorly developed. This work reports on bimetallic model compounds of nickel that interconvert between functional structures [Ni2(µ-S)2]+/2+ and isomeric congeners [2{κ-S–Ni}]2+/+, S = Aryl-S−, in which the nickel ions are geometrically independent. Interconversion of the two sets of structures was studied quantitatively by UV–VIS absorption spectroscopy and cyclic voltammetry. Assembly of the [Ni2(µ-S)2]+ core from [2{κ-S–Ni}]+ is thermodynamically and kinetically highly preferred over the disassembly of [Ni2(µ-S)2]2+ into [2{κ-S–Ni}]2+. Labile Ni-η2/3-bonding to aromatic π-systems of the primary thiophenol ligand is critical for modeling (dis)assembly processes. A phosphine coligand mimics the role of anionic donors present in natural sites that saturate metal coordination. Three parameters have been identified as critical for structure formation and persistence. These are, first, the stereoelectronic properties of the metals ions, second, the steric demand of the coligand, and, third, the properties of the dative bond between nickel and coligand. The energies of transition states connecting functional and precursor forms have been found to depend on these parameters.

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“…All manipulations of air‐ and moisture‐sensitive compounds were carried out under an atmosphere of dry argon by using standard Schlenk or glovebox techniques. Literature procedures were followed for the preparation of starting materials (Ph 3 P) 2 NiN(SiMe 3 ) 2 , 1,1′‐diacetylferrocenium bis(trifluoromethylsulfonyl)imide, [Fc′′]NTf 2 , 1 ‐[2Ni‐2S] 0/+ , 2 ‐[2Ni‐2S] 0/+ , 3 ‐[2Ni‐2S] 0/+ , and t Bu‐substituted 1 ‐[2Ni‐2S] + , with 1 =PMe 3 , 2 =PPh 3 , and 3 =PCy 3 . General information on the purification of other starting materials, solvents, and additional reagents is provided in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Mechanistic Aspects of Redox‐Induced Assembly and Disassembly of S‐Bridged [2M‐2S] Structures

Koch

Berkefeld

Speiser

et al. 2017

Chemistry A European J

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Sulfur-bridged binuclear structures [2M-2S] play a pivotal role in a variety of chemical processes such as bond breaking and formation and electron transfer. In general, structural persistence is deemed essential to the respective function but owing to the lack of a suitable molecular model system, the current understanding of the factors that control the thermodynamic and kinetic stability of [2M-2S] cores clearly is limited. This work reports a series of binuclear complexes of nickel derived from a 1,4-terphenyldithiophenol ligand platform that is ideally suited for mechanistic work to overcome this limitation. Redox-induced assembly and disassembly of S-bridged [2M-2S] fragments have been investigated at the molecular level. As part of an extended square scheme, metastable binuclear structures that are significant mechanistically have been identified, characterized, and their reactivity studied quantitatively. Electronic properties that are inherent to [2M-2S] structures and determine thermodynamic and kinetic stability are differentiated from steric effects imposed by co-ligands.

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Controlling Near-Infrared Chromophore Electronic Properties through Metal–Ligand Orbital Alignment

Cited by 15 publications

References 61 publications

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms

Understanding Factors that Control the Structural (Dis)Assembly of Sulphur-Bridged Bimetallic Sites

Mechanistic Aspects of Redox‐Induced Assembly and Disassembly of S‐Bridged [2M‐2S] Structures

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Controlling Near-Infrared Chromophore Electronic Properties through Metal–Ligand Orbital Alignment

Cited by 15 publications

References 61 publications

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ3-N,N′,C and κ3-N,N′,O Donor Platforms

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ3-N,N′,C and κ3-N,N′,O Donor Platforms

Understanding Factors that Control the Structural (Dis)Assembly of Sulphur-Bridged Bimetallic Sites

Mechanistic Aspects of Redox‐Induced Assembly and Disassembly of S‐Bridged [2M‐2S] Structures

Contact Info

Product

Resources

About

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms

Broadly versus Barely Variable Complex Chromophores of Planar Nickel(II) from κ³-N,N′,C and κ³-N,N′,O Donor Platforms