[Ru(py) 4 Cl(NO)](PF 6 ) 2 ·0.5H 2 O: a model system for structural determination and ab initio calculations of photo-induced linkage NO isomers (original) (raw)
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Inorganic Chemistry, 2000
Low-temperature IR experiments on crystalline samples of trans-[Ru(NH 3 ) 4 (NO) nicotinamide] 3+ salts show a light-induced absorption band typical for MS1 NO linkage isomers upon exposure to 300-500 nm light from a Xe source. The formation of a metastable species is confirmed by DSC measurement on a sample irradiated at low temperature with 457 nm light from an Ar + laser. The light-induced species decays between 250 and 260 K according to both IR and DSC results. This decay temperature (T d ) is somewhat below that observed for other high-T d linkage isomers, even though the NO-stretching frequency of the of [Ru(NH 3 ) 4 (NO) nicotinamide] 3+ ion is above that of the other isomers, demonstrating a lack of precise correlation between the two physical properties. The 90 K crystal structure of trans-[Ru(NH 3 ) 4 (NO)nicotinamide](SiF 6 )(NO 3 )‚H 2 O is reported. The geometry from theoretical DFT calculations of the ground-state structure agrees well with the experimental results, except for the orientation of the CONH 2 substituent in the pyridine ring, which is rotated by 180°in the crystal due to packing effects. The MS1 and MS2 linkage isomers are found to correspond to local minima on the ground-state potential energy surface, and their geometries and energies are reported.
Reversible photoswitching between nitrito-N and nitrito-O isomers in trans-[Ru(py)4(NO2)2]
Physical Chemistry Chemical Physics, 2010
Nitro-nitrito photoisomerisation is investigated in solid samples and solutions of trans-[Ru(py) 4 (NO 2 ) 2 ]. Using light of wavelength 325 nm 50% of the N-bound Ru-NO 2 ligands can be switched to the O-bound Ru-ONO configuration (nitrito-N to nitrito-O isomerisation) at temperatures below T = 250 K in solids. The population of the isomeric configurations is determined with infrared spectroscopy from the decrease of the area of the n(NO) stretching and d(NO) deformation modes. In a frozen methanol-ethanol solution nearly 100% can be converted to the nitrito-O configuration. Upon heating above T = 250 K the Ru-NO 2 configuration is restored. The nitrito-O RuÀONO configuration can be partially transferred back to the nitrito-N configuration by irradiation with light in the spectral range 405-442 nm. Using absorption spectroscopy on a frozen methanol-ethanol solution, two new bands at 447 and 380 nm are observed in the nitrito-O configuration compared to one at 334 nm of the nitrito-N ground state configuration. The photoconversion is initiated by the metal-to ligand charge transfer transition Ru(d)p*(NO 2 ,py) as shown by the calculated partial density of states using Density Functional Theory. The calculations yield also the structure of the nitrito-N and nitrito-O isomer as well as the corresponding vibrational densities. The experimental structure of the ground state is determined using powder diffraction.
Inorganic Chemistry, 2008
Nitrosyl complexes with {Ru-NO} 6 and {Ru-NO} 7 configurations have been isolated in the framework of [Ru(trpy)(L)(NO)] n+ [trpy) 2,2′:6′,2′′-terpyridine, L) 2-phenylimidazo[4,5-f]1,10-phenanthroline] as the perchlorate salts [4](ClO 4) 3 and [4](ClO 4) 2 , respectively. Single crystals of protonated material [4-H + ](ClO 4) 4 • 2H 2 O reveal a RuN -O bond angle of 176.1(7)°and triply bonded NO with a 1.127(9) Å bond length. Structures were also determined for precursor compounds of [4] 3+ in the form of [Ru(trpy)(L)(Cl)](ClO 4) • 4.5H 2 O and [Ru(trpy)-(L-H)(CH 3 CN)](ClO 4) 3 • H 2 O. In agreement with largely NO centered reduction, a sizable shift in ν(NO) frequency was observed on moving from [4] 3+ (1953 cm-1) to [4] 2+ (1654 cm-1). The Ru II-NO • in isolated or electrogenerated [4] 2+ exhibits an EPR spectrum with g 1) 2.020, g 2) 1.995, and g 3) 1.884 in CH 3 CN at 110 K, reflecting partial metal contribution to the singly occupied molecular orbital (SOMO); 14 N (NO) hyperfine splitting (A 2) 30 G) was also observed. The plot of ν(NO) versus E°({RuNO} 6 f {RuNO} 7) for 12 analogous complexes [Ru(trpy)(L′)(NO)] n+ exhibits a linear trend. The electrophilic Ru-NO + species [4] 3+ is transformed to the corresponding Ru-NO 2system in the presence of OHwith k) 2.02 × 10-4 s-1 at 303 K. In the presence of a steady flow of dioxygen gas, the Ru II-NO • state in [4] 2+ oxidizes to [4] 3+ through an associatively activated pathway (∆S q)-190.4 J K-1 M-1) with a rate constant (k [s-1 ]) of 5.33 × 10-3. On irradiation with light (Xe lamp), the acetonitrile solution of paramagnetic [Ru(trpy)(L)(NO)] 2+ ([4] 2+) undergoes facile photorelease of NO (k NO) 2.0 × 10-1 min-1 and t 1/2 ≈ 3.5 min) with the concomitant formation of the solvate [Ru II (trpy)(L)(CH 3 CN)] 2+ [2′] 2+. The photoreleased NO can be trapped as an Mb-NO adduct.
Long-lived light-induced metastable states in trans-[Ru(NH3)4(H2O)NO]Cl3�H2O and related compounds
Physical Chemistry Chemical Physics, 2005
The existence of two light-induced long-lived metastable states SI, SII in irradiated trans-[Ru(NH 3 ) 4 (H 2 O)NO]Cl 3 Á H 2 O and trans-[Ru(NH 3 ) 4 (OH)NO]Cl 2 is revealed by differential scanning calorimetry measurements and calculations based on density functional theory. Irradiation with light in the blue spectral range leads to the population of SI, while SII can be obtained by transferring SI into SII with irradiation of light in the near infrared spectral range. The population and transfer of the metastable states is described by exponential functions and the thermal decays are evaluated according to Arrhenius' law, yielding activation
Dalton Transactions, 2011
Chemical reactivity, photolability, and computational studies of the ruthenium nitrosyl complex with a substituted cyclam, fac- [Ru(NO)Cl 2 (k 3 N 4 ,N 8 ,N 11 (1-carboxypropyl)cyclam)]Cl·H 2 O ((1-carboxypropyl)cyclam = 3-(1,4,8,11-tetraazacyclotetradecan-1-yl)propionic acid)), (I) are described. Chloride ligands do not undergo aquation reactions (at 25 • C, pH 3). The rate of nitric oxide (NO) dissociation (k obs-NO ) upon reduction of I is 2.8 s -1 at 25 ± 1 • C (in 0.5 mol L -1 HCl), which is close to the highest value found for related complexes. The uncoordinated carboxyl of I has a pK a of~3.3, which is close to that of the carboxyl of the non coordinated (1-carboxypropyl)cyclam (pK a = 3.4). Two additional pK a values were found for I at~8.0 and~11.5. Upon electrochemical reduction or under irradiation with light (l irr = 350 or 520 nm; pH 7.4), I releases NO in aqueous solution. The cyclam ring N bound to the carboxypropyl group is not coordinated, resulting in a fac configuration that affects the properties and chemical reactivities of I, especially as NO donor, compared with analogous trans complexes. Among the computational models tested, the B3LYP/ECP28MDF, cc-pVDZ resulted in smaller errors for the geometry of I. The computational data helped clarify the experimental acid-base equilibria and indicated the most favourable site for the second deprotonation, which follows that of the carboxyl group. Furthermore, it showed that by changing the pH it is possible to modulate the electron density of I with deprotonation. The calculated NO bond length and the Ru/NO charge ratio indicated that the predominant canonical structure is [Ru III NO], but the Ru-NO bond angles and bond index (b.i.) values were less clear; the angles suggested that [Ru II NO + ] could contribute to the electronic structure of I and b.i. values indicated a contribution from [Ru IV NO -]. Considering that some experimental data are consistent with a [Ru II NO + ] description, while others are in agreement with [Ru III NO], the best description for I would be a linear combination of the three canonical forms, with a higher weight for [Ru II NO + ] and [Ru III NO].
Ground and excited state structural isomers in trans-Ru(bpy)2(L)22
Journal of Photochemistry and Photobiology A: Chemistry, 2000
Spectroscopic evidence is presented for different structural isomers of trans-[Ru(bpy) 2 (L 1)(L 1)] 2+ (L 1 or L 2 = 4-Etpy (1), py-PTZ) in which bpy is planar or nonplanar compared to cis-[Ru(bpy) 2 (py) 2 ] 2+ or [Ru(bpy) 3 ] 2+ in which bpy is planar. The nonplanar form is dominant in the ground states in low temperature glasses. The two forms appear to be in a temperature dependent equilibrium in 4:1 (v/v) ethanol/methanol at higher temperatures. The nonplanar form is converted into the planar form in the MLCT excited state(s) of 1.
Journal of the Chinese Chemical Society, 2015
In this work, we have explored the structural, electronic properties, 13 C and 1 H NMR parameters and first hyperpolarizability of Ru(NHC) 2 Cl 2 (=CH-p-C 6 H 4 X) complexes (X = H, F, Cl, Me, NH 2 , OH, CN, NO 2 , CHO, COOH) by mpw1pw91 quantum method. The X-substituent effect on structural parameters, frontier orbital energies, spectroscopic (1 H and 13 C NMR, UV) of complex was carried out. The results indicate that the substituent has played a significant role on the structures and properties of complex. 1 H and 13 C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method. Total and partial density of state (TDOS and PDOS) and also overlap population density of state (OPDOS) diagrams analysis were exhibited. In analyzing the bonding characteristics of this structure, Ru-C carbene and Ru-C NHC bonds were identified and characterized in details by Natural bond orbital (NBO) analysis.
Inorganic Chemistry, 1996
Ru 2 (O 2 C(CH 2) 6 CH 3) 4 (1a) is soluble in both coordinating (THF, CH 3 OH, CH 3 CN) and noncoordinating solvents (benzene, toluene, cyclohexane, CH 2 Cl 2), allowing its solution properties to be investigated by 1 H and 13 C NMR spectroscopy, UV/visible spectroscopy, resonance Raman spectroscopy, and cyclic voltammetry. In noncoordinating solvents, 1a exists as an oligomer, presumably by way of axial intermolecular-(-[Ru 2 ]-On n-interactions. 1 H NMR studies of 1a and [Ru 2 (O 2 C(CH 2) 6 CH 3) 4 ] + [X]-([1a] + [X]-), where X) Cl, BF 4 , or O 2 C(CH 2) 6 CH 3 , indicate that both dipolar and contact mechanisms contribute to the paramagnetic shifts of the protons. Resonances for axial and equatorial ligands are shifted upfield and downfield, respectively, by a dipolar mechanism. Aromatic ligands in the axial sites, e.g. pyridine and pyrazine, experience an enhanced upfield shift by direct π-delocalization. Comparison of the 1 H NMR signals for M 2 (O 2 CR) 4 compounds where M) Ru and O 2 CR) benzoate, toluate, butyrate, crotonate, and dimethylacrylate with those where M) Mo indicates that the equatorial carboxylate ligands in the diruthenium species also experience π-contact shifts. Variable-temperature studies and calculated estimates of dipolar shifts (using structural parameters taken from solid-state structures) indicate a significant zero-field splitting contribution to the dipolar shift. The arrangements of the toluate rings in Ru 2 (O 2 C-p-tolyl) 4-(THF) 2 , Ru 2 (O 2 C-p-tolyl) 4 (CH 3 CN) 2 , and [Ru 2 (O 2 C-p-tolyl) 4 (THF) 2 ] + [BF 4 ]-deviate by 15(1), 2.3(2), and 7.3°, respectively, from alignment with the Ru-Ru axis. The Ru-Ru distances for the two neutral and the cationic complexes are 2.27(1) Å, i.e. not significantly affected by the nature of the axial ligand (THF versus CH 3 CN) or by charge n+ (n) 0, 1). The cell parameters for Ru 2 (O 2 C-p-tolyl) 4 (THF) 2 ‚2THF at-154°C are a) 10.730(5) Å, b) 12.335(6) Å, c) 9.193(4) Å, R) 105.15(2)°,) 109.35(2)°, γ) 77.98(2)°, Z) 2 (asymmetric unit is RuC 24 H 30 O 6), d calcd) 1.559 g/cm 3 , and space group P1 h. The cell parameters for Ru 2 (O 2 C-p-tolyl) 4 (CH 3-CN) 2 ‚3CH 3 CN at-169°C are a) 27.058(3) Å, b) 10.049(1) Å, c) 17.956(2) Å,) 120.89(1)°, Z) 4, d calcd) 1.465 g/cm 3 , and space group C2/c. The cell parameters for [Ru 2 (O 2 C-p-tolyl) 4 (THF) 2 ] + [BF 4 ]-at-172°C are a) 13.056(4) Å, b) 21.358(6) Å, c) 9.199(2) Å,) 111.28(1)°, Z) 2, d calcd) 1.350 g/cm 3 , and space group C2/m. Within this series of compounds, the MM interactions vary from MM quadruple bonds (M) Cr, Mo, W) to relatively weak antiferromagnetic coupling (M) Cu). For M 2 (O 2 CR) 4 complexes with 4-fold D 4h symmetry, the d-orbital splitting
Theoretical and Comparative Study of the Complex [RuCl3(H2O)2(Gly)] by Density Functional Theory
Open Journal of Inorganic Chemistry, 2018
In this work, the use of computational methods was essential to distinguish the three possible isomeric structures of the [RuCl 3 (H 2 O) 2 (Gly)] molecule. The characterization of these molecules was performed using IR, NMR and UV-VIS simulations. Some calculations related to the optimization of structures and properties such as chemical hardness and dipole moment were also conducted. The fac-cis isomer presented promising data when compared to the experimental data, indicating that this is the likely experimentally synthesized isomer. This study demonstrates the technical utility of the computational calculations by virtue of situations that prevent the realization of X-ray diffraction.