Unusual Tilted Carbene Coordination in Carbene Complexes of Gallium(I) and Indium(I)

Abstract

Ga,In insights: A general explanation for the unusual tilted coordination mode of undisturbed gallium(I) and indium(I) carbene complexes of the weakly coordinating anion [Al(ORF)4]− (RF=C(CF3)3) is given, which is based on the experimental structures. The results are supported by extensive DFT studies.

Bildung eines homoatomaren, polycyclischen Bismut‐Polyanions, [Bi11]3−, durch Pyridin‐unterstützte Zersetzung von [GaBi3]2−

“…3À -Anionen mittels DFT-Methoden berechnet wurden, [23][24][25][26][27][28] + (IPr = 1,3-Bis(2,6-diisopropylphenyl)imidazol-2-yliden) bestimmt, demnach ein zweifach oxidiertes Analogon von D (mit anderem NHC). [32] Die Frage, ob die um zwei Elektronen reichere Spezies auch stabil wäre, lässt sich vor dem Hintergrund umfassender quantenchemischer Untersuchungen von Frenking und Mitarbeitern positiv beantworten, die vorschlugen, dass die zu D isoelektronische Carbodicarben-Familie mit formal nullwertigem Kohlenstoff stabil sein sollte, [33] was kurz darauf durch erste Synthesen von Bertrand und Mitarbeitern bestätigt wurde. [34] In der Zwischenzeit wurden sowohl theoretische [35] als auch experimentelle [36] Arbeiten mit qualitativ identischen Ergebnissen auf die schwereren Tetrel(0)-Homologe erweitert -erstere auch auf die negativ geladenen Analoga der Gruppe 13, allerdings mit Imidazolium-basierten NHCs.…”

Probing the Effect of Six-Membered N-Heterocyclic Carbene—6-Mes—on the Synthesis, Structure and Reactivity of Me2MOR(NHC) (M = Ga, In) Complexes

“…Notably, analogous results concerning the strength of M-CNHC bonds were obtained for alkoxide derivatives Me2M(OCPh2Me)(6-Mes) (M = Ga, In). (2) and C(4)), which is split into pitch and yaw angles [31,32]). …”

“…For complexes 3 and 4 X-ray diffraction analysis revealed the presence of four-coordinated gallium/indium species with the coordination sphere adopting a distorted-tetrahedral geometry. (19), NHC tilt 7.0(1), 5.6(1) (The tilt is quantified by the offset angle of the M-C bond to the C 2 axis of the NHC (defined by C(1) and the centroid of C(2) and C(4)), which is split into pitch and yaw angles [31,32] For complexes 3 and 4 X-ray diffraction analysis revealed the presence of four-coordinated gallium/indium species with the coordination sphere adopting a distorted-tetrahedral geometry. Interestingly, in contrast to essentially symmetrical gallium complex 3 (Figure 3), due to the orientation of the 6-Mes ligand with respect to In-C Me bonds, the presence of essentially asymmetrical indium complex 4 (Figure 4) (Figure 4) torsion angles, were in line with the previously characterized essentially symmetric Me 2 Ga(OCPh 2 Me)(IMes) and asymmetric Me 2 In(OCPh 2 Me)(IMes) complexes [3].…”

“…However, it was the effect of M-C 6-Mes bond on the structure and reactivity of Me 2 MeOR(6-Mes), which focused our attention. In the case of complex 3, the Ga-C 6-Mes bond (2.139 (2) (15), NHC tilt 4.42(9) (The tilt is quantified by the offset angle of the M-C bond to the C 2 axis of the NHC (The tilt is quantified by the offset angle of the M-C bond to the C 2 axis of the NHC (defined by C(1) and the centroid of C(2) and C(4)), which is split into pitch and yaw angles [31,32]). While the major set of signals revealed by the 1 H NMR of 3 and 4 was in line with the formation of Me2M(OCPh2Me)(6-Mes) (M = Ga, In), the presence of minor signal could be ascribed to the [Me2Ga(μ-OCPh2Me)]2, therefore suggesting the presence of equilibrium, analogously to 1.…”

“…While the detailed discussion on the factors affecting the carbene carbon shift in 13 C NMR, and therefore the analysis of the strength of the M-CNHC bond using the 13 C NMR spectroscopy, cannot be done at the current stage, our present research in this area focuses on the effect of the character of the M-CNHC bond, rather than only its strength, on the synthesis, structure and reactivity of group 13 metal Me2MOR(NHC) complexes. (2) and C(4)), which is split into pitch and yaw angles [31,32]). …”