Facile synthesis of multinuclear complexes based on a tetra(4-pyridyl)amidinate dirhodium(<scp>ii</scp>) dimer

Chartrand, Daniel; Hanan, Garry S.

doi:10.1039/b715205a

Cited by 19 publications

(11 citation statements)

References 23 publications

(12 reference statements)

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“… Dirhodium(II,II) complexes containing N , N' ‐bridging ligands: A1 , [124] A2 , [125] A3 , [125] A4 , [125] A5 : Ar=Ph, [126] A5 : Ar=C 6 H 4 ‐( p ‐CF 3 , p ‐Cl, p ‐OCH 3 , m ‐OCH 3 ), [127] A5 : Ar=C 6 H 3/4 ‐( p ‐Me, m ‐Me, m ‐Cl, m ‐CF 3 , 3,4‐Cl 2 , 3,5‐Cl 2 ), [25] A5: Ar=C 6 H 4 ‐( p ‐F, p ‐Me, o ‐F, o ‐Me), [109] A6 : Ar=C 6 H 4 ( p ‐Br, p ‐NH 2 , p ‐tethered Ru complex by amide bond), [40] A6 : Ar= p ‐Py, [128] A7 , [127] A8 , [129] A9 , [130] A10 [131] …”

Section: Overview Of Rh2a4 Paddlewheel Complexesmentioning

confidence: 99%

Dirhodium(II,II) Paddlewheel Complexes

Hrdina

2021

Eur J Inorg Chem

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This minireview summarizes synthetic approaches towards homoleptic dirhodium(II,II) paddlewheel complexes with the general formula Rh2A4. These complexes have found numerous applications in a wide range of chemical research and industry as catalysts, detectors, enzymatic inhibitors or building blocks for molecular scaffolds. In organic synthesis they are commonly used to transfer electron‐deficient species, they act as Lewis acids to activate unsaturated bonds, serve as hydrogenation catalysts and participate in oxidation/reduction processes. Dirhodium paddlewheel complexes are composed of the Rh‐Rh backbone and four bridging anions, which surround the core. According to the application, the electrochemical potential of the Rh atom can be modulated, as can the geometry and physical and chemical properties of the metal complex. Dirhodium complexes can be prepared in one step from basic inorganic precursors or by post‐functionalization of the paddlewheel structures.

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Section: Overview Of Rh2a4 Paddlewheel Complexesmentioning

confidence: 99%

Dirhodium(II,II) Paddlewheel Complexes

Hrdina

2021

Eur J Inorg Chem

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“…These peaks are due to restricted rotation of the pendant phenyl rings and represent the splitting of the signal of the two protons ortho to the interannular bond. This rotation is known to be restricted and has a free-energy of activation of approximately 15 kcal/mol for various rhodium dimers with an aryl moiety in the amidinate backbone. − Proton f is shifted upfield due to the proximity of a phenyl ring core above it from neighboring ligands, while e is facing in the opposite direction, away from aryl rings. This broadening effect is also observed for the protons in the meta position, but these protons are in an almost chemically equivalent environment, being less affected by the nearby aromatic rings, and subsequently, their signals do not split.…”

Section: Resultsmentioning

confidence: 99%

“…The amidine metal dimers show great stability and greater functionalization potential than the tetracarboxylate dimers, since moieties can be attached on both the central carbon and the nitrogen atoms. − The drawback to this is their limited catalytic activity, , although they have been shown to be photoactive to alkyl halide reduction and mixed amidinate and diimine dimers have also gathered interest as an all-in-one chromophore–catalyst system for hydrogen production . For their part, the tetraamidinate metal dimers have been used to form larger, often mixed-metal, assemblies. − In this study, we look at a postmodification of a dirhodium dimer formed with four 4-bromo- N , N ′-diphenylbenzamidine ligands via a Suzuki coupling to attach a pyridyl motif, − thus creating new binding sites on the complex. − …”

Section: Introductionmentioning

confidence: 99%

Optoelectronic Properties and Structural Effects of the Incremental Addition of Pyridyl Moieties on a Rhodium Dimer

Chartrand

Hanan

2014

J. Phys. Chem. A

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The synthesis and characterization of five C-C coupling products obtained from the reaction of a paddlewheel tetrakis 4-bromo-N,N'-diphenylbenzamidinate dirhodium dimer with 4-pyridineboronic acid pinacol ester are reported. The coupling reactions occur on one to four amidinate ligands, leading to rhodium dimers containing [tetrakis, tris, cis-bis, trans-bis, or mono]-N,N'-diphenyl-4-(pyridin-4-yl)benzamidinate ligands, effectively creating new binding sites on the metal complexes. The new compounds were isolated by column chromatography, and the exact conformations were verified by X-ray crystallography. Redox processes showed only a small variation within the coupling products and included two oxidations (1.30 ± 0.02 V, 0.27 ± 0.01 V vs SCE) and one reduction (-1.55 ± 0.02 V vs SCE), all centered on the Rh-Rh core. Time-dependent density functional theory (TD-DFT) was used to analyze this series with four other fully characterized N,N'-diphenyl-aryl-amidinate rhodium dimers that were found in the literature. The two main absorption bands of these nine rhodium dimers were compared to TD-DFT calculations, both giving excellent correlation. The first, a metal-to-metal (MM) transition around 11800 cm(-1) (845 nm) was blue-shifted in the calculation, with an average difference of 1378 cm(-1) but had only a 15 cm(-1) standard deviation, showing a strong correlation despite the energy difference. The second, a metal-to-ligand charge transfer (MLCT) transition around 18900 cm(-1) (530 nm) was a near perfect match with only a 64 cm(-1) average difference and a 35 cm(-1) standard deviation. The electronic transition, redox potentials, and HOMO and LUMO energies of all dimers were plotted versus the Hammett parameter (σ) of the aryl group and Taft's model with 2 components: field effects (σF) and resonance (σR). The properties involving only the Rh-Rh core (MM band, all oxidation potentials, HOMO and LUMO) were fit with a single set of σF and σR contributions (73% and 27%), with a goodness-of-fit (R(2)) value ranging from 90% to 99.7%. The metal-dimer to ligand charge-transfer band, involving the amidinate ligand, displayed different values of contribution with 45% and 55% for the σF and σR, respectively, with a fit of 94.8%. The accuracy of these fits enables the designed modification of amidinate-based dirhodium complexes to achieve desirable redox and spectroscopic properties.

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“…Amidine compounds are well developed in organic chemistry (Patai & Rappoport, 1991). Their derivatives are also good chelators for transition metals and their complexes have found widespread use in catalysis, polymerization reactions, as functional materials, and in supramolecular chemisty (Bambirra et al, 2004;Kazeminejad et al, 2019;Qian et al, 2010;Loh et al, 2014;Boeré et al, 1998;Chartrand & Hanan, 2008).…”

Section: Chemical Contextmentioning

confidence: 99%

N,N′-Bis[2,6-bis(1-methylethyl)phenyl]pyridine-4-carboximidamide toluene hemisolvate

et al. 2021

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The title compound, C30H39N3·0.5C7H8, is a symmetrically N,N′-disubstituted arylamidine containing a 4-pyridyl substituent on the carbon atom of the N–C–N linkage and bulky 2,6-diisopropylphenyl groups on the nitrogen atoms. It crystallizes in the Z-anti configuration and its amidine C—N bonds present amine [1.368 (1) Å] and imine [1.286 (1) Å] features. Intramolecular hydrogen bonds are present in the structure together with intermolecular N—H...N and C—H...N interactions linking the molecules in chains along the a- and c-axis directions.

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Facile synthesis of multinuclear complexes based on a tetra(4-pyridyl)amidinate dirhodium(ii) dimer

Abstract: Four rhenium(I) chromophores attached to a dirhodium(n) core form a new hexametallic light-harvesting assembly as characterised by X-ray crystallography, UV-vis spectroscopy and electrochemistry.

Cited by 19 publications

References 23 publications

Dirhodium(II,II) Paddlewheel Complexes

Dirhodium(II,II) Paddlewheel Complexes

Optoelectronic Properties and Structural Effects of the Incremental Addition of Pyridyl Moieties on a Rhodium Dimer

N,N′-Bis[2,6-bis(1-methylethyl)phenyl]pyridine-4-carboximidamide toluene hemisolvate

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