Ruthenium-Nitrosyl Complexes with Glycine, L-Alanine, L
... adenocarcinoma).14,15 These results were in strong contrast to previous comparative studies on homologous ruthenium and osmium complexes (with metal ion in different oxidation ...
... adenocarcinoma).14,15 These results were in strong contrast to previous comparative studies on homologous ruthenium and osmium complexes (with metal ion in different oxidation ...
Can Transition Metals and Group II Mono
... on the chalcogen, oxygen produced the largest ΔEHH with B3LYP, in average excess of 0.30 kJ/mol in 9 of 12 homo-heterochiral pairs grouped by metal type. With MP2, however, oxygen produced the largest average ΔEHH in only 5 of 12 pairs by 0.39 kJ/mol, while selenium produced the greatest average ΔEH ...
... on the chalcogen, oxygen produced the largest ΔEHH with B3LYP, in average excess of 0.30 kJ/mol in 9 of 12 homo-heterochiral pairs grouped by metal type. With MP2, however, oxygen produced the largest average ΔEHH in only 5 of 12 pairs by 0.39 kJ/mol, while selenium produced the greatest average ΔEH ...
Chapter 5
... cycled and linear products. This chapter presents the results of a DFT study on a proposed reaction mechanism, the energy profile for which was established by determining the structures and relative energies of the putative intermediates involved. The energy barriers for the most important steps wer ...
... cycled and linear products. This chapter presents the results of a DFT study on a proposed reaction mechanism, the energy profile for which was established by determining the structures and relative energies of the putative intermediates involved. The energy barriers for the most important steps wer ...
CHAPTER 23 THE TRANSITION ELEMENTS AND THEIR
... Coordination compounds act like electrolytes, i.e., they dissolve in water to yield charged species. However, the complex ion itself does not dissociate. The “number of individual ions per formula unit” refers to the number of ions that would form per coordination compound upon dissolution in water. ...
... Coordination compounds act like electrolytes, i.e., they dissolve in water to yield charged species. However, the complex ion itself does not dissociate. The “number of individual ions per formula unit” refers to the number of ions that would form per coordination compound upon dissolution in water. ...
Ken Raymond
... – Gd(III), with 7 unpaired electrons and a long electronic relaxation time, is ideally suited for such agents – Current Gd(III)-based commercial agents have very poor contrast enhancement capabilities due to their low relaxivity ...
... – Gd(III), with 7 unpaired electrons and a long electronic relaxation time, is ideally suited for such agents – Current Gd(III)-based commercial agents have very poor contrast enhancement capabilities due to their low relaxivity ...
Coinage Metal−Ethylene Complexes Supported
... level of theory is 1.338 Å,5a an ∼4% lengthening of CC bond upon coordination to copper. The average CC distances for the [RB(3-(R1),5-(R2)Pz)3]Ag(C2H4) and [RB(3-(R1),5-(R2)Pz)3]Au(C2H4) complexes are 1.380(4) and 1.422(6) Å, respectively. The average CC distance in the [RB(3-(R1),5-(R2)Pz)3]Cu(C2H ...
... level of theory is 1.338 Å,5a an ∼4% lengthening of CC bond upon coordination to copper. The average CC distances for the [RB(3-(R1),5-(R2)Pz)3]Ag(C2H4) and [RB(3-(R1),5-(R2)Pz)3]Au(C2H4) complexes are 1.380(4) and 1.422(6) Å, respectively. The average CC distance in the [RB(3-(R1),5-(R2)Pz)3]Cu(C2H ...
Introductory Guide to Organonickel Chemistry - Wiley-VCH
... In addition to the s-bonding, there operates another bonding mechanism, socalled ‘‘back bonding’’ or ‘‘back donation’’. As is illustrated in Figure 1.2(c), the p orbital of the CO has a proper symmetry with the dp atomic orbital of the Ni, and these two interact to each other to make up a new p-bo ...
... In addition to the s-bonding, there operates another bonding mechanism, socalled ‘‘back bonding’’ or ‘‘back donation’’. As is illustrated in Figure 1.2(c), the p orbital of the CO has a proper symmetry with the dp atomic orbital of the Ni, and these two interact to each other to make up a new p-bo ...
Design and synthesis optimization of bis(β
... polylactide less useful.[11] Alkoxides of different metals such as tin, germanium, calcium and iron have been prepared and evaluated in ROP of lactide.[12-‐17] These findings were crucial in terms ...
... polylactide less useful.[11] Alkoxides of different metals such as tin, germanium, calcium and iron have been prepared and evaluated in ROP of lactide.[12-‐17] These findings were crucial in terms ...
Structure Identification of Ni-Fe Oxide Mixture
... structure of a compound. XANES compares the light that goes in and out of the sample. When light hits a sample, scattering and fluorescence emission occurs. Therefore, the light that hits the sample is not the same as the light that gets transmitted. The photons from the light can use their energy t ...
... structure of a compound. XANES compares the light that goes in and out of the sample. When light hits a sample, scattering and fluorescence emission occurs. Therefore, the light that hits the sample is not the same as the light that gets transmitted. The photons from the light can use their energy t ...
2Cu 2+ + O 2 2
... but differ in the particular environment of the Fe centers: -Hr coordination sphere is more histidine rich -Hr permits only terminal O2-coordination to a single iron, while sMMO diiron center presents open or labile coordination sites on both Fe -sMMO shows much greater coordinative flexibility upon ...
... but differ in the particular environment of the Fe centers: -Hr coordination sphere is more histidine rich -Hr permits only terminal O2-coordination to a single iron, while sMMO diiron center presents open or labile coordination sites on both Fe -sMMO shows much greater coordinative flexibility upon ...
the Scanned PDF - Mineralogical Society of America
... (FeOu)e- coordination polyhedra. Values of the ligand field parameters 10D4, B and C were found to be 14000-15900,550-610, and 34tX)-3500 crn-r, respectively. The lowest energy ligand-to-metal charge-transfer transition is near 40,000 cm-1 in agreement with the molecular orbital calculations. The Fe ...
... (FeOu)e- coordination polyhedra. Values of the ligand field parameters 10D4, B and C were found to be 14000-15900,550-610, and 34tX)-3500 crn-r, respectively. The lowest energy ligand-to-metal charge-transfer transition is near 40,000 cm-1 in agreement with the molecular orbital calculations. The Fe ...
Study of η6 - cyclic π-perimeter hydrocarbon ruthenium complexes
... 6), as their (complexes 1–4, 6) PF6 salt or (complex 5) BF4 salt. The complexes were obtained by treatment of respective precursors, [(η6 -arene)Ru(μ-Cl)Cl]2 (arene = C6 H6 , p-i PrC6 H4 Me, C6 Me6 ) in 1:2 and 1:1 molar ratio with pppdH and dppdH in the presence of NH4 PF6 /NH4 BF4 . All the comple ...
... 6), as their (complexes 1–4, 6) PF6 salt or (complex 5) BF4 salt. The complexes were obtained by treatment of respective precursors, [(η6 -arene)Ru(μ-Cl)Cl]2 (arene = C6 H6 , p-i PrC6 H4 Me, C6 Me6 ) in 1:2 and 1:1 molar ratio with pppdH and dppdH in the presence of NH4 PF6 /NH4 BF4 . All the comple ...
transition-metals-colours-and-reactions
... Factors affecting colours The colour of a transition metal compound is determined by the difference in energy between its d orbitals. This can be affected by several factors: ...
... Factors affecting colours The colour of a transition metal compound is determined by the difference in energy between its d orbitals. This can be affected by several factors: ...
Thermal properties
... In metals, electronic contribution is very high. Thus metals have higher thermal conductivities. It is same as electrical conduction. Both conductivities are related through Wiedemann-Franz law: k ...
... In metals, electronic contribution is very high. Thus metals have higher thermal conductivities. It is same as electrical conduction. Both conductivities are related through Wiedemann-Franz law: k ...
The synthesis and X-ray structural characterization of mer and
... The reaction of H[TcNOCl4] with the tridentate ligand PNPpr gives a mixture of mer or fac isomers of TcCl2(NO)(PNPpr). Both complexes display linear nitrosyl ligands with the expected multiple bonding throughout the Tc–N–O linkage. The infrared spectra display the absorptions associated with the nit ...
... The reaction of H[TcNOCl4] with the tridentate ligand PNPpr gives a mixture of mer or fac isomers of TcCl2(NO)(PNPpr). Both complexes display linear nitrosyl ligands with the expected multiple bonding throughout the Tc–N–O linkage. The infrared spectra display the absorptions associated with the nit ...
raman spectroscopy of transition metal complexes: molecular
... Raman spectra recorded at variable temperature and pressure provide quantitative insight on frequency variations, leading to detailed information ranging from molecular electronic structure to solid-state phase transitions. The first two examples presented in the following are the variable-temperatu ...
... Raman spectra recorded at variable temperature and pressure provide quantitative insight on frequency variations, leading to detailed information ranging from molecular electronic structure to solid-state phase transitions. The first two examples presented in the following are the variable-temperatu ...
IJCA 47A(4) 560-564
... case, the ligand behaves as a tetradentate ligand with the lone electron pairs of azomethine nitrogen atoms and the lone electron pairs of two oxygen in ether groups. In the second case, the ligand behaves as a bidentate ligand with the lone electron pairs of azomethine nitrogen atoms. The long dist ...
... case, the ligand behaves as a tetradentate ligand with the lone electron pairs of azomethine nitrogen atoms and the lone electron pairs of two oxygen in ether groups. In the second case, the ligand behaves as a bidentate ligand with the lone electron pairs of azomethine nitrogen atoms. The long dist ...
Spin crossover
Spin Crossover (SCO), sometimes referred to as spin transition or spin equilibrium behavior, is a phenomenon that occurs in some metal complexes wherein the spin state of the complex changes due to external stimuli such as a variation of temperature, pressure, light irradiation or an influence of a magnetic field.With regard to a ligand field and ligand field theory, the change in spin state is a transition from a low spin (LS) ground state electron configuration to a high spin (HS) ground state electron configuration of the metal’s d atomic orbitals (AOs), or vice versa. The magnitude of the ligand field splitting along with the pairing energy of the complex determines whether it will have a LS or HS electron configuration. A LS state occurs because the ligand field splitting (Δ) is greater than the pairing energy of the complex (which is an unfavorable process).Figure 1 is a simplified illustration of the metal’s d orbital splitting in the presence of an octahedral ligand field. A large splitting between the t2g and eg AOs requires a substantial amount of energy for the electrons to overcome the energy gap (Δ) to comply with Hund’s Rule. Therefore, electrons will fill the lower energy t2g orbitals completely before populating the higher energy eg orbitals. Conversely, a HS state occurs with weaker ligand fields and smaller orbital splitting. In this case the energy required to populate the higher levels is substantially less than the pairing energy and the electrons fill the orbitals according to Hund’s Rule by populating the higher energy orbitals before pairing with electrons in the lower lying orbitals. An example of a metal ion that can exist in either a LS or HS state is Fe3+ in an octahedral ligand field. Depending on the ligands that are coordinated to this complex the Fe3+ can attain a LS or a HS state, as in Figure 1.Spin crossover refers to the transitions between high to low, or low to high, spin states. This phenomenon is commonly observed with some first row transition metal complexes with a d4 through d7 electron configuration in an octahedral ligand geometry. Spin transition curves are a common representation of SCO phenomenon with the most commonly observed types depicted in Figure 2 in which γHS (the high-spin molar fraction) is plotted vs. T. The figure shows a gradual spin transition (left), an abrupt transition with hysteresis (middle) and a two-step transition (right). For a transition to be considered gradual, it typically takes place over a large temperature range, even up to several hundred K, whereas for a transition to be considered abrupt, it should take place within 10 K or less.These curves indicate that a spin transition has occurred in a metal complex as temperature changed. The gradual transition curve is an indication that not all metal centers within the complex are undergoing the transition at the same temperature. The abrupt spin change with hysteresis indicates a strong cooperativity, or “communication”, between neighboring metal complexes. In the latter case, the material is bistable and can exist in the two different spin states with a different range of external stimuli (temperature in this case) for the two phenomena, namely LS → HS and HS → LS. The two-step transition is relatively rare but is observed, for example, with dinuclear SCO complexes for which the spin transition in one metal center renders the transition in the second metal center less favorable.There are several types of spin crossover that can occur in a complex; some of them are light induced excited state spin trapping (LIESST), ligand-driven light induced spin change (LD-LISC), and charge transfer induced spin transition (CTIST).