Electron Accumulative Molecules

Abstract

With the goal to produce molecules with high electron accepting capacity and low reorganization energy upon gaining one or more electrons, a synthesis procedure leading to the formation of a B-N(aromatic) bond in a cluster has been developed. The research was focused on the development of a molecular structure able to accept and release a specific number of electrons without decomposing or change in its structural arrangement. The synthetic procedure consists of a parallel decomposition reaction to generate a reactive electrophile and a synthesis reaction to generate the B-N(aromatic) bond. This procedure has paved the way to produce the metallacarboranylviologen [M(CBH)(CBH)-NCH-CHN-M'(CBH)(CBH)] (M = M' = Co, Fe and M = Co and M' = Fe) and semi(metallacarboranyl)viologen [3,3'-M(8-(NCH-CHN-1,2-CBH)(1',2'-CBH)] (M = Co, Fe) electron cumulative molecules. These molecules are able to accept up to five electrons and to donate one in single electron steps at accessible potentials and in a reversible way. By targeted synthesis and corresponding electrochemical tests each electron transfer (ET) step has been assigned to specific fragments of the molecules. The molecules have been carefully characterized, and the electronic communication between both metal centers (when this situation applies) has been definitely observed through the coplanarity of both pyridine fragments. The structural characteristics of these molecules imply a low reorganization energy that is a necessary requirement for low energy ET processes. This makes them electronically comparable to fullerenes, but on their side, they have a wide range of possible solvents. The ET from one molecule to another has been clearly demonstrated as well as their self-organizing capacity. We consider that these molecules, thanks to their easy synthesis, ET, self-organizing capacity, wide range of solubility, and easy processability, can find important application in any area where ET is paramount.

Synthesis, photophysical and electronic properties of tetra-donor- or acceptor-substitutedortho-perylenes displaying four reversible oxidations or reductions

“…However, (Bmes 2 ) 4 -Per shows stability towards very high reduction potentials with the advantage that it has a high electron capacity, as up to four electrons can be stored. This intriguing property is interesting for applications including molecular switches, 161,162 receptors, 162,163 photoactive dyads 164 or photocatalysis. 143,165 The donor-substituted counterpart, (DPA) 4 -Per, can be oxidized up to ve times according to cyclic voltammetry studies a Excited at the respective l abs (max) of S 1 ) S 0 .…”

Synthesis and study ofC-substituted methylthio derivatives of cobalt bis(dicarbollide)

“…[1][2][3][4][5] Among the various derivatives of carboranes, special attention is paid to p-complexes of transition metals with carborane ligands, called metallacarboranes. The most known of them, cobalt bis(dicarbollide) [3,3 0 -Co(1,2-C 2 B 9 H 11 ) 2 ] À attracts increasing interest from researchers working in various elds from medical chemistry to [6][7][8][9][10][11] materials science [12][13][14][15][16][17][18] to due to its extraordinary high stability, low toxicity 19 and almost unlimited possibilities for chemical modication. 20,21 Recently, we suggested that cobalt bis(dicarbollide) can be used as a structural element in the design of molecular switches.…”

Reversibly Switchable Fluorescent Molecular Systems Based on Metallacarborane–Perylenediimide Conjugates

“…A more complex behavior was encountered for the cathodic region, where reversible waves were detected for the consecutive, two‐step reduction of the PDI unit to its dianion ( E 1/2 ∼−0.60 and −0.80 V (vs. SCE)), and for the Co III →Co II reduction of the COSAN metal cluster ( E 1/2 ∼−1.47 V (vs. SCE)). Notably, minor differences were observed for the redox signals registered for 1 and 2 concerning reference compounds 3 and 7 , which further evidence that the COSAN and PDI moieties are not electronically coupled in the conjugates [30] …”