1,3,5-[(tBu2MeSi)2Si]3C6H3: Isolable Si-centered Triradical with a High-spin Quartet Ground State

Abstract

Reductive deiodination of 1,3,5-tris[2,2-di-tert-butyl-1-(ditert-butylmethylsilyl)-1-iodo-2-methyldisilanyl]benzene (1) with KC 8 results in the formation of isolable Si-centered triradical 1,3,5-[( t Bu 2 MeSi) 2 Si] 3 C 6 H 3 (2), which was characterized by X-ray crystallography and electron paramagnetic resonance (EPR) spectroscopy. The quartet ground state for triradical 2 was established using EPR spectroscopy by Curie plots (560 K) for the characteristic ¦m = 2 and ¦m = 3 transitions.

Radicals and Anions of Siloles and Germoles

“…We attempted the synthesis of germolyl radicals by careful stoichiometric reduction of the corresponding germolyl halides 1 with potassium graphite according to procedures published by the group of Sekiguchi [21–23] . In the case of 1‐phenyl and 1‐ tert ‐butyl substituted germolyl halides 1 a and 1 b only the corresponding Ge−Ge bonded dimers 2 a,b were obtained, indicating insufficient steric shielding of the intermediate germolyl radical.…”

“…We attempted the synthesis of germolyl radicals by careful stoichiometric reduction of the corresponding germolyl halides 1 with potassium graphite according to procedures published by the group of Sekiguchi. [ 21 , 22 , 23 ] In the case of 1‐phenyl and 1‐ tert ‐butyl substituted germolyl halides 1 a and 1 b only the corresponding Ge−Ge bonded dimers 2 a,b were obtained, indicating insufficient steric shielding of the intermediate germolyl radical. Both compounds were isolated in moderate to good yields and fully characterized by NMR spectroscopy and their molecular structures in the solid state were determined by X‐ray diffraction (XRD) analysis.…”

Radicals and Anions of Siloles and Germoles

“…We attempted the synthesis of germolyl radicals by careful stoichiometric reduction of the corresponding germolyl halides 1 with potassium graphite according to procedures published by the group of Sekiguchi. [21][22][23] In the case of 1-phenyl and 1tert-butyl substituted germolyl halides 1 a and 1 b only the corresponding GeÀ Ge bonded dimers 2 a,b were obtained, indicating insufficient steric shielding of the intermediate germolyl radical. Both compounds were isolated in moderate to good yields and fully characterized by NMR spectroscopy and their molecular structures in the solid state were determined by X-ray diffraction (XRD) analysis.…”

Heteroatom-Based Diradical(oid)s

“…A typical example is shown in Figure . − Computations already showed the preference for the triplet ground state of the m -phenylene-bridged bis­(silyl) diradical 112 over its singlet state with a singlet–triplet gap of +20 kcal mol –1 . This was further corroborated by EPR measurements at 80 K. The EPR spectrum shows characteristic signals at 335.2 mT ( g = 2.0034) comprising six lines with the zfs parameters D = 6.4 × 10 –3 cm –1 (13.8 mT) and E = 0.80 × 10 –3 cm –1 (1.72 mT).…”