Isolation of a Carborane‐Fused Triazole Radical Anion

Abstract

Außerhalb des Käfigs: Die Redoxeigenschaften eines Triazol‐anellierten Carboran‐Anions werden durch Methylierung und Zwitterionenbildung so verändert, dass die Verbindung eine einfache chemische Reduktion zu einem isolierbaren Triazol‐Radikalanion eingeht (siehe Struktur: C grau, H weiß, N blau, B braun, Cl grün). Das Radikalanion ist durch kinetischen Schutz und die Delokalisierung der Spindichte über das π‐System außerhalb des Clusters stabilisiert.

Tuning the Electrochemical Potential of Perfunctionalized Dodecaborate Clusters Through Vertex Differentiation

“…However, it remains unclear whether highly reversible redox behavior is inherent to only B 12 (OR) 12 species and whether electronic perturbations on the cluster core with mixed substituents other than the alkoxy group can produce molecules with similar properties. [20][21][22][23][24][25][26] Here we present a new approach to further tune the redox properties of the perfunctionalized B 12based clusters by substituting one of the OR moieties with an NO 2 group, thus introducing an additional structural handle via heterofunctionalization. As a result, a new class of [B 12 (OR) 11 NO 2 ] 2-/1-/0 clusters can be isolated which feature unique photophysical properties when compared to those of their [B 12 (OR) 12 ] analogues can be obtained.…”

Activation of B H bonds in Ir(I) complexes supported by phosphine with carba-closo-dodecaborate and o-carborane ligand substituents: A DFT investigation

“…Since the discovery of o-carborane in 1963 [1][2][3][4][5][6][7][8], the carboranyl-and carbollide-based transition metal complexes have been paid more attention due to their high stability [9][10][11][12][13][14][15][16][17][18]. Moreover, icosahedral carboranes are interesting alternatives to the classical alkyl and aryl ligand substituents because of their shape and 3-dimension aromaticity [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], such as o-carborane phosphine [29], o-bis(dimethylsilyl) carborane [30], phenyl(2-p-carboranyl)-iodonium [31], o-carboranyl phenols [32], iPr 2 NB(C 9 H 7 )(C 2 B 10 H 11 ) [33], 9,12-Bis-(4-acetylphenyl)-1,2-dicarbadodecaborane [17] and so on. In addition, the cyclometalated iridium (III) complexes have been used as efficient phosphorescent emitters in organic light-emitting diodes (OLEDs) and solid-state lighting because they have excellent photophysical properties and stability [34][35][36][37]…”

Fusing N‐Heterocyclic Carbenes with Carborane Anions

“…All five atoms of the central heterocyclic ring are coplanar (sum of internal pentagon angles = 5408) and both N1 and N3 are planar (sum of C-N-C angles = 3608). [1f, 8, 13] The carboranenitrogen bond lengths (N1-C7 1.4521 (15), N3-C6 1.4514 (14) ) and carbon-boron distances in the cluster (average C-B distance 1.719 (3) ) are nearly identical to the precursor 7 (N1-C7/N3-C6 1.455 (3), average C-B distance 1.716 (3) ), indicating no exo-p conjugation with the carbene ring or disruption of the three-dimensionally aromatic carborane core of 8. [1f, 8, 13] The carboranenitrogen bond lengths (N1-C7 1.4521 (15), N3-C6 1.4514 (14) ) and carbon-boron distances in the cluster (average C-B distance 1.719 (3) ) are nearly identical to the precursor 7 (N1-C7/N3-C6 1.455 (3), average C-B distance 1.716 (3) ), indicating no exo-p conjugation with the carbene ring or disruption of the three-dimensionally aromatic carborane core of 8.…”

“…Relative to the monoanionic imidazolium precursor 7 (see Supporting Information for crystallographic data), the nitrogen-carbene bond lengths of 8 (N1-C2 1.3657 (14), N3-C2 1.3645 (15) ) are elongated with respect to the imidazolium anion 7 (N1-C2/N3-C2 1.331 (2) )), which is in line with standard NHCs and their Li complexes. [1f, 8, 13] The carboranenitrogen bond lengths (N1-C7 1.4521 (15), N3-C6 1.4514 (14) ) and carbon-boron distances in the cluster (average C-B distance 1.719 (3) ) are nearly identical to the precursor 7 (N1-C7/N3-C6 1.455 (3), average C-B distance 1.716 (3) ), indicating no exo-p conjugation with the carbene ring or disruption of the three-dimensionally aromatic carborane core of 8. [9a, 15] The carbene-lithium bond length of 2.110 (2) is in the range reported for standard NHC lithium complexes.…”