Continuous Symmetry Measures: A New Tool in Quantum Chemistry

Alemany, Pere; Casanova, David; Álvarez, Santiago; Dryzun, Chaim; Avnir, David

doi:10.1002/9781119356059.ch7

Cited by 48 publications

(45 citation statements)

References 144 publications

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“…The N ‐Ru−N bond angles are very close to 90° for the dipyridyl ketone moieties and slightly smaller for the more flexible dipyridyl methyl amine moieties of the cpmp and ddpd ligands. The shape parameter S (OC‐6) quantifying the deviation from an ideal octahedron is close to zero, corroborating the high local [RuN 6 ] symmetry in all cases (Table ) as expected for a metal ion with low‐spin d 6 electron configuration. The steric strain, as measured from the pyramidalization of the bridging nitrogen atoms, inversely correlates to the degree of planarization PL/%=100×[∑(X‐ N ‐Y)–3×109.5°]/ [3×120.0°–3×109.5°].…”

Section: Resultssupporting

confidence: 77%

Green‐Light Activation of Push–Pull Ruthenium(II) Complexes

Moll

Wang

Päpcke

et al. 2020

Chemistry A European J

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Synthesis, characterization, electrochemistry,a nd photophysicso fh omo-a nd heteroleptic ruthenium(II) complexes [Ru(cpmp) 2 ] 2 + (2 2 + + )a nd [Ru(cpmp)(ddpd)] 2 + (3 2 + + ) bearing the tridentate ligands 6,2''-carboxypyridyl-2,2'-methylamine-pyridyl-pyridine( cpmp)a nd N,N'-dimethyl-N,N'-dipyridin-2-ylpyridine-2,6-diamine (ddpd) are reported. The complexes possess one (3 2 + + )o rt wo (2 2 + + )e lectron-deficient dipyridyl ketone fragments as electron-accepting sites enabling intraligand charget ransfer (ILCT), ligand-to-ligand charge transfer (LL'CT) and low-energy metal-to-ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). Complex 2 2 + + shows 3 MLCT phosphor-escencei nthe red to near-infrared spectral region at room temperature in deaerated acetonitrile solution with an emission quantum yield of 1.3 %a nd a 3 MLCT lifetimeo f4 77 ns, whereas 3 2 + + is much less luminescent. This different behavior is ascribed to the energy gap law and the shape of the parasitic excited 3 MC state potential energy surface. This study highlights the importance of the excited-state energies and geometries for the actual excited-state dynamics. Aromatic and aliphatic amines reductively quench the excited state of 2 2 + + paving the way to photocatalytic applications using low-energyg reen light as exemplified with the green-light-sensitized thiol-ene click reaction.Scheme1.Benchmarkruthenium(II) complexesa nd their absorption/ emission band maxima.[a] J.Scheme3.Photocatalytic radical thiol-eneclick reaction utilizing the (green) light-induced reductive quenching pathway of [RuLL] 2 + = 2 2 + + , 3 2 + + and [Ru(bpy) 3 ] 2 + mediated by p-toluidine (Ar = p-C 6 H 4 -CH 3 )a ccordingt oref.[71] (R = CH 2 -CHNHBoc-COOCH 3 ).

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Section: Resultssupporting

confidence: 77%

Green‐Light Activation of Push–Pull Ruthenium(II) Complexes

Moll

Wang

Päpcke

et al. 2020

Chemistry A European J

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“…All homoleptic complexes [M(ddpd) 2 ] n+ and [M(tpy) 2 ] n+ share a [MN 6 ] coordination sphere. The deviation of the experimental coordination geometry from the ideal octahedron can be expressed by a continuous shape measure S(OC-6) as implemented in the program SHAPE 2.1 (free download at http://www.ee.ub.es) [54][55][56][57][58]. For an ideal octahedron, this value will be zero and increases with the structural deviation.…”

Section: Properties Of the Ligand Ddpdmentioning

confidence: 99%

Ddpd as Expanded Terpyridine: Dramatic Effects of Symmetry and Electronic Properties in First Row Transition Metal Complexes

et al. 2018

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The 2,2′:6′:2″-terpyridine ligand has literally shaped the coordination chemistry of transition metal complexes in a plethora of fields. Expansion of the ligand bite by amine functionalities between the pyridine units in the tridentate N,N’-dimethyl-N,N’-dipyridine-2-yl-pyridine-2,6-diamine ligand (ddpd) modifies the properties of corresponding transition metal complexes, comprising redox chemistry, molecular dynamics, magnetism and luminescence. The origins of these differences between ddpd and tpy complexes will be elucidated and comprehensively summarized with respect to first row transition metal complexes with d2–d10 electron configurations. Emerging applications of these ddpd complexes complementary to those of the well-known terpyridine ligand will be highlighted.

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“…[30] Indeed referring to the above mentioned "autonomous existence of chemical entities", working with contemporary theoretical chemists based in Spain, Avnir subsequently extended the CSM methodology, originally conceived to treat the geometric symmetry of molecular structures defined as a set of points in three-dimensional Euclidean space, to deal with the degree of symmetry of more complex mathematical objects commonly used in quantum chemistry such as wave functions, orbitals, and electron densities. [31]…”

Section: An Updated Look At Moleculesmentioning

confidence: 99%