η⁶‐Germabenzene Complexes of Chromium and Molybdenum

Coordination Chemistry of a Kinetically Stabilized Germabenzene: Syntheses and Properties of Stable η6‐Germabenzene Complexes Coordinated to Transition Metals

“…Structures of h 6 -germabenzene complexes: Complexes 2-4 were characterized by their 1 H and 13 C NMR, IR, and UV/ Vis spectra. NMR measurements on 2-4 showed that, in solution, each germabenzene ligand-as well as free 1-had a C 2 axis passing through the Ge and C4 atoms.…”

“…[9a] Such spectral features are similar to those observed in the case of arene tricarbonylmetal complexes, which generally show NMR signals shifted upfield relative to those of the free aromatic compounds, due to the reduction of p-electron density in the arene ring on complex formation. [14] In addition, the chemical shifts corresponding to the germabenzene rings in 2-4 were observed at slightly higher field than the range for the corresponding h [14b] In addition, the 13 )]. The intense absorptions appearing at the longest wavelength for 2-4 can be assigned to the metalto-ligand charge transfer (MLCT) band, in accordance with the calculated and experimentally observed electronic spec-…”

“…In the 1 H and 13 C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1. X-ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO) 3 3 A C H T U N G T R E N N U N G (CH 3 CN)] (M = Cr, Mo), resulting in the formation of the first stable h 6 -germabenzene-Group 6 metal complexes, [M(CO) 3 (h 6 -C 5 H 5 GeTbt)].…”

“…The first stable h 6 -germabenzene complexes, that is, [M(CO) 3 (h 6 -C 5 H 5 GeTbt)] {M = Cr (2), Mo (3), and W (4); Tbt = 2,4,6-tris- 3 ] (M = Cr, Mo, and W) and the kinetically stabilized germabenzene 1 and characterized by 1 H and 13 C NMR, IR, and UV/Vis spectroscopy. In the 1 H and 13 C NMR spectra of 2-4, all of the signals for the germabenzene rings were shifted upfield relative to their counterparts in the free germabenzene 1.…”

“…X-ray crystallographic analysis of 2 and 4 revealed that the germabenzene ligand was nearly planar and was coordinated to the M(CO) 3 3 A C H T U N G T R E N N U N G (CH 3 CN)] (M = Cr, Mo), resulting in the formation of the first stable h 6 -germabenzene-Group 6 metal complexes, [M(CO) 3 (h 6 -C 5 H 5 GeTbt)]. [13] In this paper we describe the details of the synthesis and characterization of the first stable h 6 -germabenzene-Group 6 metal complexes, [M(CO) 3 …”