Electronic structure of oxidized complexes derived from cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its photoisomerization mechanism

Nora Planas; Laura Vigara; Clyde Cady; Pere Miró; Ping Huang; Leif Hammarström; Stenbjörn Styring; Nils Leidel; Holger Dau; Michael Haumann; Laura Gagliardi; Christopher J. Cramer; Antoni Llobet

doi:10.1021/ic201686c

Electronic structure of oxidized complexes derived from cis-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ and its photoisomerization mechanism

Nora Planas
, Laura Vigara
, Clyde Cady
, Pere Miró
, Ping Huang
, Leif Hammarström
, Stenbjörn Styring
, Nils Leidel
, Holger Dau
, Michael Haumann
, Laura Gagliardi
, Christopher J. Cramer
, Antoni Llobet

Chemistry (Twin Cities)

Research output: Contribution to journal › Article › peer-review

60 Scopus citations

Abstract

The geometry and electronic structure of cis-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ and its higher oxidation state species up formally to Ru ^VI have been studied by means of UV-vis, EPR, XAS, and DFT and CASSCF/CASPT2 calculations. DFT calculations of the molecular structures of these species show that, as the oxidation state increases, the Ru-O bond distance decreases, indicating increased degrees of Ru-O multiple bonding. In addition, the O-Ru-O valence bond angle increases as the oxidation state increases. EPR spectroscopy and quantum chemical calculations indicate that low-spin configurations are favored for all oxidation states. Thus, cis-[Ru ^IV(bpy) ₂(OH) ₂] ²⁺ (d ⁴) has a singlet ground state and is EPR-silent at low temperatures, while cis-[Ru ^V(bpy) ₂(O)(OH)] ²⁺ (d ³) has a doublet ground state. XAS spectroscopy of higher oxidation state species and DFT calculations further illuminate the electronic structures of these complexes, particularly with respect to the covalent character of the O-Ru-O fragment. In addition, the photochemical isomerization of cis-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ to its trans-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ isomer has been fully characterized through quantum chemical calculations. The excited-state process is predicted to involve decoordination of one aqua ligand, which leads to a coordinatively unsaturated complex that undergoes structural rearrangement followed by recoordination of water to yield the trans isomer.

Original language	English (US)
Pages (from-to)	11134-11142
Number of pages	9
Journal	Inorganic chemistry
Volume	50
Issue number	21
DOIs	https://doi.org/10.1021/ic201686c
State	Published - Nov 7 2011

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Planas, N., Vigara, L., Cady, C., Miró, P., Huang, P., Hammarström, L., Styring, S., Leidel, N., Dau, H., Haumann, M., Gagliardi, L., Cramer, C. J., & Llobet, A. (2011). Electronic structure of oxidized complexes derived from cis-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ and its photoisomerization mechanism. Inorganic chemistry, 50(21), 11134-11142. https://doi.org/10.1021/ic201686c

@article{82faf67d67df4929bc1796de83081c77,

title = "Electronic structure of oxidized complexes derived from cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its photoisomerization mechanism",

abstract = "The geometry and electronic structure of cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its higher oxidation state species up formally to Ru VI have been studied by means of UV-vis, EPR, XAS, and DFT and CASSCF/CASPT2 calculations. DFT calculations of the molecular structures of these species show that, as the oxidation state increases, the Ru-O bond distance decreases, indicating increased degrees of Ru-O multiple bonding. In addition, the O-Ru-O valence bond angle increases as the oxidation state increases. EPR spectroscopy and quantum chemical calculations indicate that low-spin configurations are favored for all oxidation states. Thus, cis-[Ru IV(bpy) 2(OH) 2] 2+ (d 4) has a singlet ground state and is EPR-silent at low temperatures, while cis-[Ru V(bpy) 2(O)(OH)] 2+ (d 3) has a doublet ground state. XAS spectroscopy of higher oxidation state species and DFT calculations further illuminate the electronic structures of these complexes, particularly with respect to the covalent character of the O-Ru-O fragment. In addition, the photochemical isomerization of cis-[Ru II(bpy) 2(H 2O) 2] 2+ to its trans-[Ru II(bpy) 2(H 2O) 2] 2+ isomer has been fully characterized through quantum chemical calculations. The excited-state process is predicted to involve decoordination of one aqua ligand, which leads to a coordinatively unsaturated complex that undergoes structural rearrangement followed by recoordination of water to yield the trans isomer.",

author = "Nora Planas and Laura Vigara and Clyde Cady and Pere Mir{\'o} and Ping Huang and Leif Hammarstr{\"o}m and Stenbj{\"o}rn Styring and Nils Leidel and Holger Dau and Michael Haumann and Laura Gagliardi and Cramer, \{Christopher J.\} and Antoni Llobet",

year = "2011",

month = nov,

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doi = "10.1021/ic201686c",

language = "English (US)",

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T1 - Electronic structure of oxidized complexes derived from cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its photoisomerization mechanism

AU - Planas, Nora

AU - Vigara, Laura

AU - Cady, Clyde

AU - Miró, Pere

AU - Huang, Ping

AU - Hammarström, Leif

AU - Styring, Stenbjörn

AU - Leidel, Nils

AU - Dau, Holger

AU - Haumann, Michael

AU - Gagliardi, Laura

AU - Cramer, Christopher J.

AU - Llobet, Antoni

PY - 2011/11/7

Y1 - 2011/11/7

N2 - The geometry and electronic structure of cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its higher oxidation state species up formally to Ru VI have been studied by means of UV-vis, EPR, XAS, and DFT and CASSCF/CASPT2 calculations. DFT calculations of the molecular structures of these species show that, as the oxidation state increases, the Ru-O bond distance decreases, indicating increased degrees of Ru-O multiple bonding. In addition, the O-Ru-O valence bond angle increases as the oxidation state increases. EPR spectroscopy and quantum chemical calculations indicate that low-spin configurations are favored for all oxidation states. Thus, cis-[Ru IV(bpy) 2(OH) 2] 2+ (d 4) has a singlet ground state and is EPR-silent at low temperatures, while cis-[Ru V(bpy) 2(O)(OH)] 2+ (d 3) has a doublet ground state. XAS spectroscopy of higher oxidation state species and DFT calculations further illuminate the electronic structures of these complexes, particularly with respect to the covalent character of the O-Ru-O fragment. In addition, the photochemical isomerization of cis-[Ru II(bpy) 2(H 2O) 2] 2+ to its trans-[Ru II(bpy) 2(H 2O) 2] 2+ isomer has been fully characterized through quantum chemical calculations. The excited-state process is predicted to involve decoordination of one aqua ligand, which leads to a coordinatively unsaturated complex that undergoes structural rearrangement followed by recoordination of water to yield the trans isomer.

AB - The geometry and electronic structure of cis-[Ru II(bpy) 2(H 2O) 2] 2+ and its higher oxidation state species up formally to Ru VI have been studied by means of UV-vis, EPR, XAS, and DFT and CASSCF/CASPT2 calculations. DFT calculations of the molecular structures of these species show that, as the oxidation state increases, the Ru-O bond distance decreases, indicating increased degrees of Ru-O multiple bonding. In addition, the O-Ru-O valence bond angle increases as the oxidation state increases. EPR spectroscopy and quantum chemical calculations indicate that low-spin configurations are favored for all oxidation states. Thus, cis-[Ru IV(bpy) 2(OH) 2] 2+ (d 4) has a singlet ground state and is EPR-silent at low temperatures, while cis-[Ru V(bpy) 2(O)(OH)] 2+ (d 3) has a doublet ground state. XAS spectroscopy of higher oxidation state species and DFT calculations further illuminate the electronic structures of these complexes, particularly with respect to the covalent character of the O-Ru-O fragment. In addition, the photochemical isomerization of cis-[Ru II(bpy) 2(H 2O) 2] 2+ to its trans-[Ru II(bpy) 2(H 2O) 2] 2+ isomer has been fully characterized through quantum chemical calculations. The excited-state process is predicted to involve decoordination of one aqua ligand, which leads to a coordinatively unsaturated complex that undergoes structural rearrangement followed by recoordination of water to yield the trans isomer.

UR - https://www.scopus.com/pages/publications/80155150454

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SN - 0020-1669

VL - 50

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EP - 11142

JO - Inorganic chemistry

JF - Inorganic chemistry

IS - 21

ER -

Electronic structure of oxidized complexes derived from cis-[Ru ^II(bpy) ₂(H ₂O) ₂] ²⁺ and its photoisomerization mechanism

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