Stereoelectronic Mapping of Dithiocarbamates and Xanthates

Leung, Jia Nuo; Huynh, Han Vinh

doi:10.1021/acs.inorgchem.2c03387

Cited by 4 publications

(6 citation statements)

References 45 publications

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“…This map shows that diimines are a versatile class of ligands with a good range of easily tunable electronic and steric properties, which could in principle meet the demands of different applications. Notably, similar maps have been used in preliminary SAR studies concerning the catalytic performance of iron–NHC complexes and the cytotoxicity of gold-dithiocarbamato compounds. , …”

Section: Resultsmentioning

confidence: 99%

“…Notably, similar maps have been used in preliminary SAR studies concerning the catalytic performance of iron−NHC complexes and the cytotoxicity of gold-dithiocarbamato compounds. 62,63 ■ CONCLUSIONS A series of palladium-NHC complexes of azole-derived diimines were prepared to determine the donor strengths of bidentate nitrogen ligands. It was discovered that subtle changes in the ligand structure led to electronic differences that could be accurately distinguished by HEP2.…”

Section: Syntheses Of Palladium(ii) Nhc Complexes Bearingmentioning

confidence: 99%

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Stereoelectronic Profiling of Neutral and Monoanionic Biimidazoles and Mixed Diimines

2023

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14 mono-, di-, and tetranuclear palladium complexes were prepared to study the coordination chemistry of symmetrical and unsymmetrical azole-derived diimines and their anions. The diverse range of complexes obtained highlights the structural and electronic diversities imposed by these ligands. Using the monopalladium species, the electronic properties of selected bidentate ligands were determined, ranked, and compared by 13 C NMR spectroscopy, extending the scope of the HEP2 (Huynh electronic parameter 2) scale, which can detect even subtle differences. Moreover, the %V bur (percentage volume buried) values as an estimate for the steric bulk of some ligands were determined using the solid-state molecular structures of their complexes, and a preliminary stereoelectronic map was established.

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Section: Resultsmentioning

confidence: 99%

Section: Syntheses Of Palladium(ii) Nhc Complexes Bearingmentioning

confidence: 99%

Stereoelectronic Profiling of Neutral and Monoanionic Biimidazoles and Mixed Diimines

2023

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“…The difference is more pronounced (ΔHEP2 = 0.7−0.9 ppm) compared to the monodentate ligands (ΔHEP = 0.3−0.4 ppm), presumably due to the electronic distribution across two donor sites in a bidentate coordination mode. Overall, the bidentate κ 2 -(S)PoxIm ligands are weaker donors than diNHCs (177−180 ppm), 38 dithiocarbamates/xanthates (174−179 ppm), 42 and monoanionic C^N chelators (176− 185 ppm), 43,44 but stronger donors than neutral diimines (157−164 ppm). 15,40 Their donicities are similar to those of N^O β-ketiminate chelators (NacAcs) (∼170 ppm) 43 and lie in the higher donor range of monoanionic N^N chelators (165−173 ppm).…”

Section: Synthesis Of Palladium(ii) Complexes Bearing Bidentate κ 2 -...mentioning

confidence: 99%

Electronic Profiling of N-Phosphine Oxide-Substituted Imidazolin-2-ylidenes (PoxIms) and Imidazolidin-2-ylidenes (SPoxIms)

Leung,

Mondori,

Ogoshi

et al. 2024

Inorg. Chem.

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A detailed electronic study of the N-phosphine oxide functionalized imidazolin-2-ylidenes (PoxIms) and imidazolidin-2ylidenes (SPoxIms) has been performed experimentally using IR, 13 C, and 77 Se NMR spectroscopies. While the net donor/acceptor properties of the (S)PoxIms could not be differentiated via IR spectroscopy (TEP), NMR spectroscopic methods (HEP, Se) reveal that the (S)PoxIms are slightly weaker σ-donors but stronger πacceptors compared to common NHCs. Moreover, backbone and substituent-effects could also be resolved by the latter, allowing for a ranking of their electronic properties. Finally, the donicities of these well-designed NHC ligands in their bidentate κ 2 -C,O modes were evaluated using HEP2 and compared to those of classical chelators.

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“…The formation of trinuclear and multinuclear complexes is also a possible option. They can act as intermediates, represent resting states, or block the catalytic cycle by generating stable nonreactive species. − …”

Section: Introductionmentioning

confidence: 99%

Expanding the Role of Dimeric Species: On-Cycle Involvement, Improved Stability, and Control of Stereo-Specificity. A Case Study of Atom-Economic Catalytic Hydrothiolation

et al. 2023

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A common assumption that dimeric metal complexes in many catalytic systems represent a resting state and are not directly involved in catalytic processes was revised in a combined experimental and theoretical study. On-cycle participation of dimeric metal complexes, rather than typically assumed off-cycle involvement, was revealed, and advantageous performance in terms of improved selectivity was observed. The conceptual rationalization for the participation of dimeric species in the catalytic cycle was developed. The Pd-catalyzed hydrothiolation process (where strong Pd−S binding is well established and a persistent opinion for the inactive/poisoning role of dimeric species is presumed) was evaluated as a challenging system to test the concept. Activation of an (NHC)Pd(Cl)(acac) precatalyst (NHC�N-heterocyclic carbene and acac�acetylacetonate) under the reaction conditions produced monomeric (NHC)Pd(SPh) 2 or dimeric (NHC) 2 Pd 2 (SPh) 4 species depending on the steric bulkiness of the NHC ligand. Dimeric complexes possessed higher selectivity and tolerated disulfide impurities in contrast to monomeric complexes. Quantum chemical modeling suggested that dimeric catalysis proceeds through the opening of only one (μ-SPh)−Pd bridging bond with retention of the dimeric structure. The second bridging bond is maintained, which prevents the monomerization of the complex. Catalytically active species were detected in a hydrothiolation reaction by high-resolution mass spectrometry and NMR spectroscopy. Proving the opportunity for productive homogeneous catalysis via strongly coordinated dimeric metal species opens new opportunities for catalyst design in the increased nuclearity dimension.

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Stereoelectronic Mapping of Dithiocarbamates and Xanthates

Cited by 4 publications

References 45 publications

Stereoelectronic Profiling of Neutral and Monoanionic Biimidazoles and Mixed Diimines

Stereoelectronic Profiling of Neutral and Monoanionic Biimidazoles and Mixed Diimines

Electronic Profiling of N-Phosphine Oxide-Substituted Imidazolin-2-ylidenes (PoxIms) and Imidazolidin-2-ylidenes (SPoxIms)

Expanding the Role of Dimeric Species: On-Cycle Involvement, Improved Stability, and Control of Stereo-Specificity. A Case Study of Atom-Economic Catalytic Hydrothiolation

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