Functional (Supra)Molecular Nanostructures - ruben-group

Recommendations

Info

Habilitation Dr. Mario Ruben ULP Strasbourg obvious structural similarity to the “charge containers” within the quantum dot cellular automata concept. Figure 24. Schematic representation and working principle of “cellular automata” concept: a) Coulomb repulsion keeps the electron density (dark) at antipodal sites resulting in the degenerated “1” and “0” state. b) A wire of “cellular automata” can be formed by a one- dimensional arrangement of cells. The intercellular Coulomb interactions force all units into the same state. c) Working principle of a majority logic gate consisting of three inputs (A, B, C) which converge on an output (Maj(A;B;C;)). In order to prove the suitability of [2x2] metal ion arrays for such and further novel data processing concepts, the electronic properties of a series of [M II 4L4]–complexes were investigates in solution as well at surfaces. In solution, the electrochemical behavior of a family of tetranuclear grid-like oligopyridine complexes of the general formula [M4 II (L)4] 8+ displays well-resolved multiple one-electron reductions in all complexes investigated. [47] Furthermore, the introduction of electron donating or attracting <strong>group</strong>s into the ligands tunes systematically the potential of the first reduction. As a consequence, one Co4 II member of this family exhibits up to twelve well-resolved reversible one-electron processes at room temperature, which appears to be the most extended redox series known for well characterized molecular compounds (Figure 25). 37
Habilitation Dr. Mario Ruben ULP Strasbourg Figure 25. Sequential twelve-electron reduction of a [Co II 4(F)4] 8+ array in dimethylformamide (DMF) at room temperature (left) and spectro-electrochemistry in acetonitrile of the same compound exhibiting the progressive increase of the ligand-based radical bands with increasing negative potential. The rather low values of the redox potentials are of importance for the stability of the multi-electron species generated and thus for their possible applications as devices presenting multiple electronic levels. Spectro-electrochemical experiments revealed that the reductions take place on the coordinated ligands in all cases; no reduction of the metal centers was observed in the accessible potential range. Interestingly, the Co4 II species exhibited an amazing regularity in the disposition of the reduction waves, as well as a remarkable stability and reversibility towards reduction (Figure 25). In contrast, all non-Co4 II arrays (with M II = Fe II , Ru II , Os II , Zn II , and Mn II ) were found to be more sensitive towards decomposition and to produce more complex reduction schemes. Obviously, the nature of the M II ions in grid-like complexes plays a very important role for mediating electronic communication within the metallo-organic supramolecular array. In order to understand the reasons for the very peculiar behaviour of the Co4 II complexes, a theoretical model involving strongly-correlated electrons was developed. The model illustrates the interplay between electron addition and intramolecular spin coupling of localized magnetic moments at the Co II -cornerstones and delocalized reduction electrons in ligand orbitals. As expected, the extra electrons injected into bridging ligand orbitals introduce a ferromagnetic (FE) spin correlation between the Co II metal ions. However, for certain numbers of reduction electrons (n=3 or 5), sufficiently strong Coloumb interactions can stabilize an unexpected high spin ground state of Stot=7/2. This finding is explained by 38
Page 1 and 2: Habilitation Dr. Mario Ruben ULP St
Page 27 and 28: 6. Molecular Magnetism Habilitation
Page 37: 7. Molecular Electronics Habilitati
Page 47 and 48: 9. Conclusion Habilitation Dr. Mari
Page 55: Habilitation Dr. Mario Ruben ULP St
Page 58 and 59: Highlights previously described gri
Page 60 and 61: Metallosupramolecular Chemistry Rec
Page 62 and 63: Metallosupramolecular Chemistry Fig
Page 64 and 65: Metallosupramolecular Chemistry Tho
Page 66 and 67: Metallosupramolecular Chemistry two
Page 70 and 71: Metallosupramolecular Chemistry (Fi
Page 72 and 73: Metallosupramolecular Chemistry The
Page 76 and 77: Metallosupramolecular Chemistry [3]
Page 78 and 79: DOI: 10.1039/b303922f Synthesis of
Page 82 and 83: enable a highly efficient informati
Page 84 and 85: implies a multistep SC process, whi
Page 86 and 87: e716 Scheme 1. Fig. 1. 1 H-NMR spec
Page 88:
FULL PAPER Supramolecular Spintroni
Page 91 and 92:
Supramolecular Spintronic Devices 4
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
merge, since the molecular surround
Page 99 and 100:
Supramolecular Spintronic Modules F
Page 101 and 102:
Supramolecular Spintronic Modules r
Page 103 and 104:
APS/123-QED Quantum Tunneling of th
Page 105 and 106:
certain fields, which are shifted t
Page 107 and 108:
[3] Transition metal catalyzed form
Page 109 and 110:
transfer of four electrons at ‡1.
Page 111 and 112:
Functional Supramolecular Devices:
Page 113 and 114:
Functional Supramolecular Devices 2
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
��¨
Page 123 and 124:
��
Page 125 and 126:
ΔE 0.06 0.05 0.04 0.03 0.02 0.01 0
Page 127 and 128:
�¦��
Page 129 and 130:
Figure 1. The masters on the roof o
Page 131 and 132:
to have approached him in late 1926
show all

Functional (Supra)Molecular Nanostructures - ruben-group

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?