Photoelectron spectroscopic and computational study of the PtMgH3
... Thus, the PtMgH3 cluster can be viewed as an activated Z2-H2 molecule attached to a PtMgH moiety. Clusters exhibiting Z2-bonded H2 have been seen in M(CO3)(Pr3)2(H2),31 in (Z2-H2)CuCl clusters in argon matrices,32 in gas-phase [HPd(Z2-H2)] species,18 and in both (Z2-H2)CuF and (Z2-H2)AgCl neutral cl ...
... Thus, the PtMgH3 cluster can be viewed as an activated Z2-H2 molecule attached to a PtMgH moiety. Clusters exhibiting Z2-bonded H2 have been seen in M(CO3)(Pr3)2(H2),31 in (Z2-H2)CuCl clusters in argon matrices,32 in gas-phase [HPd(Z2-H2)] species,18 and in both (Z2-H2)CuF and (Z2-H2)AgCl neutral cl ...
Computational Evidence of the Importance of Substituent Bulk on
... The complex IrH2(PtBu2Ph)2+ is a remarkable candidate for an agostic bond. It is a 14-electron species with two empty orbitals, a positive charge to increase the Lewis acidic character of the metal, numerous CH bonds to donate to the electrondeficient Ir, and no π-donor ligand to stabilize the high ...
... The complex IrH2(PtBu2Ph)2+ is a remarkable candidate for an agostic bond. It is a 14-electron species with two empty orbitals, a positive charge to increase the Lewis acidic character of the metal, numerous CH bonds to donate to the electrondeficient Ir, and no π-donor ligand to stabilize the high ...
A Metal-Based Inhibitor of Tumor Necrosis Factor-α
... ICM method [ICM-Pro 3.6-1d molecular docking software].[14] The geometry of both isomers was optimized using density functional theory (DFT) calculations. The ligands were docked to a grid representation of the receptor and assigned a score reflecting the quality of the complex. In the lowest-energy ...
... ICM method [ICM-Pro 3.6-1d molecular docking software].[14] The geometry of both isomers was optimized using density functional theory (DFT) calculations. The ligands were docked to a grid representation of the receptor and assigned a score reflecting the quality of the complex. In the lowest-energy ...
Oscillatory concentration pulses of some divalent metal ions induced
... ions were mixed with the ‘‘optimal composition’’ in the CSTR. During the oscillatory cycle, monitored by following the pH in time, dramatic visual changes were seen in the reactor: the reaction mixture was crystal clear in the acidic pH range (2.5–6); turbidity started to appear at pH 6–7; precipita ...
... ions were mixed with the ‘‘optimal composition’’ in the CSTR. During the oscillatory cycle, monitored by following the pH in time, dramatic visual changes were seen in the reactor: the reaction mixture was crystal clear in the acidic pH range (2.5–6); turbidity started to appear at pH 6–7; precipita ...
![Theoretical Study in [C2 H4 –Tl]](http://s1.studyres.com/store/data/002722361_1-eb696f17258f2d22bec64ad25583944b-300x300.png)
experiment
... Coloured compounds are used in a variety of obvious applications. We encounter these in dyes for our cloth, pH indicators and pigments for paints. Dyes are commonly organic compounds, they adhere well to fabric, are nontoxic and inexpensive. However, they tend to fade over time, like indigo, the dye ...
... Coloured compounds are used in a variety of obvious applications. We encounter these in dyes for our cloth, pH indicators and pigments for paints. Dyes are commonly organic compounds, they adhere well to fabric, are nontoxic and inexpensive. However, they tend to fade over time, like indigo, the dye ...
ZERO-FIELD ANISOTROPIC SPIN HAMILTONIANS IN FIRST-ROW APPLICATIONS
... WARNING. On having consulted this thesis you’re accepting the following use conditions: Spreading this thesis by the TDX (www.tesisenxarxa.net) service has been authorized by the titular of the intellectual property rights only for private uses placed in investigation and teaching activities. Reprod ...
... WARNING. On having consulted this thesis you’re accepting the following use conditions: Spreading this thesis by the TDX (www.tesisenxarxa.net) service has been authorized by the titular of the intellectual property rights only for private uses placed in investigation and teaching activities. Reprod ...
Excitation Transfer between Conjugated Polyelectrolytes and
... The combination of a transition metal ion and organic ligands gives rise not only to phosphorescence but also to an optical transition with hybrid characteristics. For organic ligands, the ligand-center (LC or π − π ∗ ) transitions are of high importance as discussed in section 2.1. For the heavy me ...
... The combination of a transition metal ion and organic ligands gives rise not only to phosphorescence but also to an optical transition with hybrid characteristics. For organic ligands, the ligand-center (LC or π − π ∗ ) transitions are of high importance as discussed in section 2.1. For the heavy me ...
The synthesis and properties of solution processable red-emitting phosphorescent dendrimers Materials Chemistry
... complex cores. The symmetric dendrimer has three dendritic 2-benzo[b]thiophene-2’-ylpyridyl (BTP) ligands with the dendritic ligands responsible for red emission. The asymmetric dendrimer has two dendritic 2-phenylpyridyl ligands and one unsubstituted BTP ligand. Iridium(III) complexes comprised of ...
... complex cores. The symmetric dendrimer has three dendritic 2-benzo[b]thiophene-2’-ylpyridyl (BTP) ligands with the dendritic ligands responsible for red emission. The asymmetric dendrimer has two dendritic 2-phenylpyridyl ligands and one unsubstituted BTP ligand. Iridium(III) complexes comprised of ...
Photochemical and Photophysical Properties of Tetranuclear and
... (Table I) are consistent with a triplet assignment for both emissive states. The excitation spectrum of 1 displays different maxima depending on whether the LE or HE emission maximum is the monitoring ~avelength.~O Interestingly, the ”A‘, for the so-called HE band occurs at lower energy than does th ...
... (Table I) are consistent with a triplet assignment for both emissive states. The excitation spectrum of 1 displays different maxima depending on whether the LE or HE emission maximum is the monitoring ~avelength.~O Interestingly, the ”A‘, for the so-called HE band occurs at lower energy than does th ...
this PDF file
... ion for a defined template molecule. Furthermore it is possible to replace the metal ion with another one to enhance the selectivity or use the MIP for different aim [11-13]. Therefore within this context metal coordination approach has an important potential for preparation of highly specific MIPs ...
... ion for a defined template molecule. Furthermore it is possible to replace the metal ion with another one to enhance the selectivity or use the MIP for different aim [11-13]. Therefore within this context metal coordination approach has an important potential for preparation of highly specific MIPs ...
Document
... The departing ligand leaves, and a discernable intermediate with a lower coordination number is formed. Rate is independent of Y, and is determined by the breaking of the M-X bond (analogous to SN1). Associative (A) Mechanism MLnX + Y → MLnXY → MLnY + X The incoming ligand adds to the complex, and a ...
... The departing ligand leaves, and a discernable intermediate with a lower coordination number is formed. Rate is independent of Y, and is determined by the breaking of the M-X bond (analogous to SN1). Associative (A) Mechanism MLnX + Y → MLnXY → MLnY + X The incoming ligand adds to the complex, and a ...
THE d- AND f-BLOCK ELEMENTS
... exhibiting colour. Ti+2[Ar]3d2, V+2[Ar]3d3 etc. These are having unpaired electrons in their ‘d’ orbitals therefore they are coloured. Transition metal ions which do not have any unpaired electrons in their ‘d’ orbitals like 3d0 and 3d10 configurations, do not exhibit any colour property. Ex.., Sc+3 ...
... exhibiting colour. Ti+2[Ar]3d2, V+2[Ar]3d3 etc. These are having unpaired electrons in their ‘d’ orbitals therefore they are coloured. Transition metal ions which do not have any unpaired electrons in their ‘d’ orbitals like 3d0 and 3d10 configurations, do not exhibit any colour property. Ex.., Sc+3 ...
Two views at strained nanocrystals from the opposite sides of spatial
... periodic lattice exists, and the latter, in the systems with disorder, where the average structure and local structure are different or the average structure does not exist at all. Ian Robinson’s research of strained nanocrystals by coherent x-ray diffraction (CXD) is an example where the strengths ...
... periodic lattice exists, and the latter, in the systems with disorder, where the average structure and local structure are different or the average structure does not exist at all. Ian Robinson’s research of strained nanocrystals by coherent x-ray diffraction (CXD) is an example where the strengths ...
Chapter 4 Chemical Bonding and Molecular Structure Question Bank
... 22) Ans: Bonding molecular orbitals 1. Formed by symmetric combination of atomic orbitals. 2. Has more electron density between the nuclei. Antibonding molecular orbitals. 1. Formed by asymmetric combination of atomic orbitals. 2. Has less electron density between the nuclei. 23) Ans: It is half of ...
... 22) Ans: Bonding molecular orbitals 1. Formed by symmetric combination of atomic orbitals. 2. Has more electron density between the nuclei. Antibonding molecular orbitals. 1. Formed by asymmetric combination of atomic orbitals. 2. Has less electron density between the nuclei. 23) Ans: It is half of ...
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).