We introduce the heterocumulene ligand [(Ad)NCC(
We report new ruthenium complexes bearing the lipophilic bathophenanthroline (BPhen) ligand and dihydroxybipyridine (dhbp) ligands which differ in the placement of the OH groups ([(BPhen)2Ru(n,n′‐dhbp)]Cl2with
- NSF-PAR ID:
- 10448412
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Photochemistry and Photobiology
- Volume:
- 98
- Issue:
- 1
- ISSN:
- 0031-8655
- Page Range / eLocation ID:
- p. 102-116
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract t Bu)]−(Ad=1‐adamantyl (C10H15),t Bu=tert ‐butyl, (C4H9)), which can adopt two forms, the azaalleneyl and ynamide. This ligand platform can undergo a reversible chelotropic shift using Brønsted acid‐base chemistry, which promotes an unprecedented spin‐state change of the [VIII] ion. These unique scaffolds are prepared via addition of 1‐adamantyl isonitrile (C≡NAd) across the alkylidyne in complexes [(BDI)V≡Ct Bu(OTf)] (A ) (BDI−=ArNC(CH3)CHC(CH3)NAr), Ar=2,6‐i Pr2C6H3) and [(dBDI)V≡Ct Bu(OEt2)] (B ) (dBDI2−=ArNC(CH3)CHC(CH2)NAr). ComplexA reacts with C≡NAd, to generate the high‐spin [VIII] complex with a κ1‐N ‐ynamide ligand, [(BDI)V{κ1‐N ‐(Ad)NCC(t Bu)}(OTf)] (1 ). Conversely,B reacts with C≡NAd to generate a low‐spin [VIII] diamagnetic complex having a chelated κ2‐C ,N ‐azaalleneyl ligand, [(dBDI)V{κ2‐N ,C ‐(Ad)NCC(t Bu)}] (2 ). Theoretical studies have been applied to better understand the mechanism of formation of2 and the electronic reconfiguration upon structural rearrangement by the alteration of ligand denticity between1 and2 . -
Abstract We introduce the heterocumulene ligand [(Ad)NCC(
t Bu)]−(Ad=1‐adamantyl (C10H15),t Bu=tert ‐butyl, (C4H9)), which can adopt two forms, the azaalleneyl and ynamide. This ligand platform can undergo a reversible chelotropic shift using Brønsted acid‐base chemistry, which promotes an unprecedented spin‐state change of the [VIII] ion. These unique scaffolds are prepared via addition of 1‐adamantyl isonitrile (C≡NAd) across the alkylidyne in complexes [(BDI)V≡Ct Bu(OTf)] (A ) (BDI−=ArNC(CH3)CHC(CH3)NAr), Ar=2,6‐i Pr2C6H3) and [(dBDI)V≡Ct Bu(OEt2)] (B ) (dBDI2−=ArNC(CH3)CHC(CH2)NAr). ComplexA reacts with C≡NAd, to generate the high‐spin [VIII] complex with a κ1‐N ‐ynamide ligand, [(BDI)V{κ1‐N ‐(Ad)NCC(t Bu)}(OTf)] (1 ). Conversely,B reacts with C≡NAd to generate a low‐spin [VIII] diamagnetic complex having a chelated κ2‐C ,N ‐azaalleneyl ligand, [(dBDI)V{κ2‐N ,C ‐(Ad)NCC(t Bu)}] (2 ). Theoretical studies have been applied to better understand the mechanism of formation of2 and the electronic reconfiguration upon structural rearrangement by the alteration of ligand denticity between1 and2 . -
Abstract Ru(II) complexes were synthesized with π‐expanding (phenyl, fluorenyl, phenanthrenyl, naphthalen‐1‐yl, naphthalene‐2‐yl, anthryl and pyrenyl groups) attached at a 1
H ‐imidazo[4,5‐f ][1,10]phenanthroline ligand and 4,4′‐dimethyl‐2,2′‐bipyridine (4,4′‐dmb) coligands. These Ru(II) complexes were characterized by 1D and 2D NMR, and mass spectroscopy, and studied for visible light and dark toxicity to human malignant melanoma SK‐MEL‐28 cells. In the SK‐MEL‐28 cells, the Ru(II) complexes are highly phototoxic (EC50 = 0.2–0.5 µm ) and have low dark toxicity (EC50 = 58–230 µm ). The highest phototherapeutic index (PI) of the series was found with the Ru(II) complex bearing the 2‐(pyren‐1‐yl)‐1H ‐imidazo[4,5‐f ][1,10]phenanthroline ligand. This high PI is in part attributed to the π‐rich character added by the pyrenyl group, and a possible low‐lying and longer‐lived3IL state due to equilibration with the3MLCT state. While this pyrenyl Ru(II) complex possessed a relatively high quantum yield for singlet oxygen formation (Φ∆ = 0.84), contributions from type‐I processes (oxygen radicals and radical ions) are competitive with the type‐II (1O2) process based on effects of added sodium azide and solvent deuteration. -
Abstract Searching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(
o ‐(Ph2P)C6H4)2GeIVCl2]PtIICl2and [(o ‐(Ph2P)C6H4)2ClGeIII]PtIIICl3, two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o ‐(Ph2P)C6H4)2ClGeIII]PtICl with quantum yields of 1.7 % and 3.2 % for the GeIV–PtIIand GeIII–PtIIIisomers, respectively. Conversion of the GeIV–PtIIisomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the GeIII–PtIIIisomer point to a ligand arene–Cl.charge‐transfer complex as an intermediate. -
Abstract Searching for a connection between the two‐electron redox behavior of Group‐14 elements and their possible use as platforms for the photoreductive elimination of chlorine, we have studied the photochemistry of [(
o ‐(Ph2P)C6H4)2GeIVCl2]PtIICl2and [(o ‐(Ph2P)C6H4)2ClGeIII]PtIIICl3, two newly isolated isomeric complexes. These studies show that, in the presence of a chlorine trap, both isomers convert cleanly into the platinum germyl complex [(o ‐(Ph2P)C6H4)2ClGeIII]PtICl with quantum yields of 1.7 % and 3.2 % for the GeIV–PtIIand GeIII–PtIIIisomers, respectively. Conversion of the GeIV–PtIIisomer into the platinum germyl complex is a rare example of a light‐induced transition‐metal/main‐group‐element bond‐forming process. Finally, transient‐absorption‐spectroscopy studies carried out on the GeIII–PtIIIisomer point to a ligand arene–Cl.charge‐transfer complex as an intermediate.