Coordination chemistry of 9-sila- and 9-germa-phenanthrenes — unique coordination modes in their metallene complexes

Abstract

Ligand exchange reactions of 9-sila-and 9-germa-phenathrenes with chromium carbonyl complexes, [Cr(CH 3 CN) 3 (CO) 3 ] and [Cr( 6 -benzene)(CO) 3 ], were performed. Their reactions with [Cr(CH 3 CN) 3 (CO) 3 ] afforded the corresponding 6 -complexes, in which Cr(CO) 3 moieties coordinated to the C 6 -rings. However, those with [Cr( 6 -benzene)(CO) 3 ] gave unique four-membered complexes bearing semibridging carbonyl ligands. All the structures of novel complexes were determined by NMR and X-ray crystallographic analysis. Résumé :Des réactions d'échange des ligands 9-silaphénanthrène et 9-germaphénanthrène avec les complexes chrome-carbonyle [Cr(CH 3 CN) 3 (CO) 3 ] et [Cr( 6 -benzene)(CO) 3 ] ont été réalisées. La réaction de ces ligands avec le complexe [Cr(CH 3 CN) 3 (CO) 3 ] a permis la formation des 6 -complexes correspondants, dans lesquels les groupes fonctionnels Cr(CO) 3 sont coordonnés avec les cycles à six carbones (C 6 ). La réaction de ces mêmes ligands avec [Cr( 6 -benzene)(CO) 3 ], a produit quant à elle des complexes uniques à quatre membres, qui portent des ligands carbonyles semi-pontants. Toutes les structures des nouveaux complexes ont été déterminées pas RMN et cristallographie aux rayons X. [Traduit par la Rédaction]

Heavier element-containing aromatics of [4n+2]-electron systems

“…In 2014, Tokitoh and co-workers reported the formation of 9sila-phenanthrene/Cr complex 6CSi3-Cr(CO)3 by the ligand exchange reactions of 9-sila-phenanthrene 6CSi3 with [Cr(CO)3(ACN)3] (Scheme 4-12). 209,210 While 6CSi3-Cr(CO)3 is thermally stable in the solid state, heating of the benzene solution of 6CSi3-Cr(CO)3 at 80 °C resulted in the mixture of free 6CSi3 and [Cr(CO)3(Ph)]. Subsequent photolysis reaction of this reaction mixture afforded an unique four-membered complex 6CSi3-Cr(CO)2(Ph) bearing semibridging carbonyl ligands.…”

“…The ligand exchange reaction of 9-germa-phenanthrene 6CGe11 with [Cr(CO)3(ACN)3] afforded the Cr complex 6CGe11-Cr(CO)3 (Scheme 4-19). 210,222 Heating of the benzene solution of 6CGe11-Cr(CO)3 gave 6CGe11 and [Cr(CO)3(Ph)], which underwent the formation of 6CGe11-Cr(CO)2(Ph) upon photolysis.…”

Iron(II) Complex with a Silacycle-Bridged Biaryl-Based Ligand

“…It should be noted here that no precedents for the construction of transition-metal complexes featuring carbanion-coordinated six-membered silacycle-bridged biaryl ligands were found, despite the fact that iridium- 18 and iron-based 19 complexes with silyl-coordinated analogous ligands have been reported. 20 Thus, it is expected that further research to improve these structural characteristics of 3 might contribute to the discovery of novel iron-based catalysts suitable for catalytic asymmetric reactions.…”