New Ruthenium Nitrosyl Complexes with Tris(1-pyrazolyl)methane (tpm) and 2,2'-Bipyridine (bpy) Coligands. Structure, Spectroscopy, and Electrophilic and Nucleophilic Reactivities of Bound Nitrosyl
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- 作者：Mariela Videla ; Juliá ; n S. Jacinto ; Ricardo Baggio ; Marí ; a T. Garland ; Priti Singh ; Wolfgang Kaim ; Leonardo D. Slep ; José ; A. Olabe
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：October 16, 2006
- 年：2006
- 卷：45
- 期：21
- 页码：8608 - 8617
- 全文大小：171K
- 年卷期：v.45,no.21(October 16, 2006)
- ISSN：1520-510X
文摘
The new compound [Ru(bpy)(tpm)NO](ClO4)3 [tpm = tris(1-pyrazolyl)methane; bpy = 2,2'-bipyridine] has been preparedin a stepwise procedure that involves the conversion of [Ru(bpy)(tpm)Cl]+ into the aqua and nitro intermediates,followed by acidification. The diamagnetic complex crystallizes to exhibit distorted octahedral geometry around themetal, with the Ru-N(O) bond length 1.774(12) Å and the RuNO angle 179.1(12)
, typical for a {RuNO}6 description.The [Ru(bpy)(tpm)NO]3+ ion (I) has been characterized by 1H NMR and IR spectroscopies (
NO = 1959 cm-1) andthrough density functional theory calculations. Intense electronic transitions in the 300-350-nm region are assignedthrough time-dependent (TD)DFT as intraligand 
* for bpy and tpm. The d *(bpy) metal-to-ligand charge-transfer transitions appear at higher energies. Aqueous cyclic voltammetric studies show a reversible wave at 0.31V (vs Ag/AgCl, 3 M Cl-), which shifts to 0.60 V in MeCN, along with the onset of a wave of an irreversible processat -0.2 V. The waves are assigned to the one- and two-electron reductions centered at the NO ligand, leading tospecies with {RuNO}7 and {RuNO}8 configurations, respectively. Controlled potential reduction of I in MeCN led tothe [Ru(bpy)(tpm)NO]2+ ion (II), revealing a significant downward shift of NO to 1660 cm-1 as well as changes in theelectronic absorption bands. II was also characterized by electron paramagnetic resonance, showing an anisotropicsignal at 110 K that arises from an S = 1/2 electronic ground state; the g-matrix components and hyperfine couplingtensor resemble the behavior of related {RuNO}7 complexes. Both I and II were characterized through their mainreactivity modes, electrophilic and nucleophilic, respectively. The addition of OH- into I generated the nitro complex,with kOH = 3.05 × 106 M-1 s-1 (25 C). This value is among the highest obtained for related nitrosyl complexes andcorrelates with ENO+/NO, the one-electron redox potential. Complex II is a robust species toward NO release, althougha conversion to I was observed in the presence of O2. This reaction afforded a second-order rate law with k = 3.5M-1 s-1 (25 C). The stabilization of the NO radical complex is attributed to the high positive charge of the precursorand to the geometrical and electronic structure as determined by the neutral tpm ligand.
, typical for a {RuNO}6 description.The [Ru(bpy)(tpm)NO]3+ ion (I) has been characterized by 1H NMR and IR spectroscopies (NO = 1959 cm-1) andthrough density functional theory calculations. Intense electronic transitions in the 300-350-nm region are assignedthrough time-dependent (TD)DFT as intraligand * for bpy and tpm. The d *(bpy) metal-to-ligand charge-transfer transitions appear at higher energies. Aqueous cyclic voltammetric studies show a reversible wave at 0.31V (vs Ag/AgCl, 3 M Cl-), which shifts to 0.60 V in MeCN, along with the onset of a wave of an irreversible processat -0.2 V. The waves are assigned to the one- and two-electron reductions centered at the NO ligand, leading tospecies with {RuNO}7 and {RuNO}8 configurations, respectively. Controlled potential reduction of I in MeCN led tothe [Ru(bpy)(tpm)NO]2+ ion (II), revealing a significant downward shift of NO to 1660 cm-1 as well as changes in theelectronic absorption bands. II was also characterized by electron paramagnetic resonance, showing an anisotropicsignal at 110 K that arises from an S = 1/2 electronic ground state; the g-matrix components and hyperfine couplingtensor resemble the behavior of related {RuNO}7 complexes. Both I and II were characterized through their mainreactivity modes, electrophilic and nucleophilic, respectively. The addition of OH- into I generated the nitro complex,with kOH = 3.05 × 106 M-1 s-1 (25 C). This value is among the highest obtained for related nitrosyl complexes andcorrelates with ENO+/NO, the one-electron redox potential. Complex II is a robust species toward NO release, althougha conversion to I was observed in the presence of O2. This reaction afforded a second-order rate law with k = 3.5M-1 s-1 (25 C). The stabilization of the NO radical complex is attributed to the high positive charge of the precursorand to the geometrical and electronic structure as determined by the neutral tpm ligand.