Bridged and unbridged M2L10 complexes

Shaik, Sason; Hoffmann, Roald; Fisel, C. Richard; Summerville, Richard H.

doi:10.1021/ja00534a001

Cited by 150 publications

(65 citation statements)

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“…The T dependent susceptibility due to the similar electronic configuration has also been reported for various complexes with metal ion pairs. 16,17) Of course, these complexes do not exhibit phase transitions. Li 2 RuO 3 is considered to present, as far as we know, a new type of phase transitions associated with the structural distortion induced by the molecular orbit formation of the d electrons.…”

Section: )mentioning

confidence: 97%

New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure

et al. 2007

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A new-type structural transition has been found in Li 2 RuO 3 with honeycomb lattice of edge-sharing RuO 6 -octahedra. With decreasing temperature T, the electrical resistivity exhibits an anomalous increase at T=T c~5 40 K, suggesting the (metal to insulator)-like transition and the magnetic susceptibility also shows a sharp decrease. Detailed structure analyses have revealed that the high temperature space group C2/m changes to P2 1 /m at T c . The most striking fact is that a significant reduction of the bond lengths is found between two of six Ru-Ru pairs of the hexagon in the low temperature phase, indicating a new type phase transition by the mechanism of the formation of molecular orbits of these Ru-Ru pairs.KEYWORDS: Li 2 RuO 3 , honeycomb structure, structural transition *Corresponding author: e43247a@nucc.cc.nagoya-u.ac.jpCompounds with the honeycomb lattice often present interesting behavior originating from their characteristic structures. For example, in the course of the studies on the physical properties of localized spin systems of A 3 T 2 SbO 6 (A=Na, Li; T=Cu, Ni, Co) and Na 2 T 2 TeO 6 on the (distorted) honeycomb lattice, spin gap behaviors have been found for T=Cu, [1][2][3] while the magnetic transitions to the spin-ordered state have been observed for T=Co and Ni. 4)As one of possible examples of conductive electrons on honeycomb lattice, we have investigated physical properties of Li 2 RuO 3 . It has the layers of the honeycomb lattice of edge-sharing RuO 6 octahedra with a LiO 6 octahedron at the center of each hexagon of RuO 6 (Fig. 1). The Ru valence is +4 and the four electrons exist in the 4d t 2g orbits. For this system, we have found a phase transition at temperature T=T c~5 40 K, where the crystal symmetry changes from a monoclinic (space group C2/m) to another monoclinic (space group P2 1 /m) one with decreasing T. As described in detail later, the transition is associated with the molecular orbit formation of Ru 4+ -Ru 4+ ions of the edge-sharing RuO 6 pair, presenting a new mechanism of structural transitions.Polycrystalline samples of Li 2 RuO 3 were prepared by sintering pellets of mixtures of RuO 2 and Li 2 CO 3 with proper molar ratio at 1000 ˚C for 24 h in air. 5,6) The powder neutron diffraction patterns of these samples indicate that a small amount of RuO 2 (molar fraction of ∼1.20 %) exists. There also exists an impurity peak of the unidentified phase, which has the integrated intensity of ~4.5 % of the maximum integrated intensity of the main phase as shown later. The magnetic susceptibilities χ were measured using a Quantum Design SQUID magnetometer under a magnetic field H=1 T in the temperature range of 2-700 K. The electrical resistivities ρ were measured by the standard four-terminal method using an ac-resistance bridge from 4.6 K to 695 K. The specific heats C were measured by a thermal relaxation method in the temperature range of 5-60 K using a Physical Property Measurement System (PPMS, Quantum Design). Powder X-ray diffraction measurements were carrie...

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Section: )mentioning

confidence: 97%

New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure

et al. 2007

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“…3 B, 5 A, and 7 B states, respectively. As the spin multiplicity increases, the ReORe bond length becomes longer due to the occupation of antibonding orbitals.…”

Section: Amentioning

confidence: 99%

“…From these results, it is concluded that the 1 A and 2 B states are the ground states of 1 and 2, respectively, which will be discussed later based on a different support. Figure 2 shows the MRMP2-calculated relative energies of the 1 5 A and 7 B states become considerably stable at the septetoptimized geometry. These results show that B3LYP-optimized geometries are expected to be similar to MRMP2-optimized geometries and the optimization by the B3LYP method is reasonable.…”

Section: Relative Energies Of Each Spin Multiplicity and Electronic Smentioning

confidence: 99%

Theoretical investigation of μ‐O‐bridged dinuclear Re complexes: Electronic structure, bonding nature, and absorption spectra

Nakao

Saito

Sakaki

2009

Int J of Quantum Chemistry

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ABSTRACT:The ground state and some low-lying excited states of [Re B states, respectively, as assigned by the MRMP2 method. Two large absorption bands about 2.1 and 2.6 eV for A1 and A2 are theoretically assigned to be 1 1 B and 2 1 B states by the MRMP2 method. These energies are calculated to be 2.12 and 2.15 eV by the MRMP2 method, which are in good agreement with the experimental values of the similar complexes. Significant difference in absorption spectra of B from those of A1 and A2 are also discussed, based on MRMP2 calculations.

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“…Thus in the case of 1, on the basis of bond length alone a single W-W bond might have been diagnosed. However, the nature of the bridging ligands has been shown both theoretically (13,14) and experimentally (15) to have a profound influence on the metal-metal separation in dinuclear complexes. The terminal ligands can also play a role in this matter (14).…”

Section: (W(iv)w(iv)) and W~( P -S ) Z ( E~~n C S~) Z ( C H~~)~mentioning

confidence: 99%

The crystal and molecular structure of di-μ-phenylthiolatobis[trichloro(dimethyl sulfide) tungsten(IV) (W—W)]

Boorman¹,

Ball²,

Moynihan³

et al. 1983

Can. J. Chem.

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has been isolated as one product of the 1: 1 reaction between WC14(Me2S)2 and SiMe3(SPh) in CH2C12 solution. A single crystal X-ray diffraction study shows that the molecule has the relatively unusual edge-shared bioctahedral structure, with a W-W bond length of 2.759(1) A. The dimethyl sulfide ligands occupy positions trans to one another in the equatorial mean plane of the molecule, which has two-fold symmetry imposed on it. The structure was solved by the heavy atom method and refined to R = 0.044 and R,,.

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Bridged and unbridged M2L10 complexes

Cited by 150 publications

References 2 publications

New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure

New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure

Theoretical investigation of μ‐O‐bridged dinuclear Re complexes: Electronic structure, bonding nature, and absorption spectra

The crystal and molecular structure of di-μ-phenylthiolatobis[trichloro(dimethyl sulfide) tungsten(IV) (W—W)]

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Bridged and unbridged M2L10 complexes

Cited by 150 publications

References 2 publications

New-Type Phase Transition of Li2RuO3 with Honeycomb Structure

New-Type Phase Transition of Li2RuO3 with Honeycomb Structure

Theoretical investigation of μ‐O‐bridged dinuclear Re complexes: Electronic structure, bonding nature, and absorption spectra

The crystal and molecular structure of di-μ-phenylthiolatobis[trichloro(dimethyl sulfide) tungsten(IV) (W—W)]

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New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure

New-Type Phase Transition of Li₂RuO₃ with Honeycomb Structure