The electron spin resonance spectra of the phenyltrimethylsilane and -germane anions: ?-bonding between silicon and germanium and the aromatic ring

Abstract

The electron spin resonance spectra of the anions of phenyltrimethyl-silane and -germane have been measured and analysed. The ring proton hyperfine constants are quite different from those of the t-butyl benzene anion and demonstrate that relative to X M e 3 , the 4 i M e 3 and --GeMe3 groups are electron attracting.

Radical anions of hypervalent silicon compounds: 1-substituted silatranes

“…2a), which is genetically related to the symmetrical component of the degenerate vacant molecular orbitals of benzene. This suggests 53,54 that Si in the -Si(OCH 2 CH 2 ) 3 N group exhibits electronegative properties towards the Ph À in 1 À and 1 À ÁK + . In contrast, in the neutral molecules XSi(OCH 2 CH 2 ) 3 N, the -Si(OCH 2 CH 2 ) 3 N moiety acts only as a s-donor towards the substituent X.…”

“…5). The experimental values 53 of a H for the RA of PhSi(CH 3 ) 3 are given in parentheses. b UMP2/6-31+G(d,p) geometry optimization of species 1 À was performed while holding the phenyl ring planar.…”

ESR. Spectra of the Radical Anion of Dimethyl‐phenyl‐phosphine

“…It is informative to compare the coupling constants reported here for I@ with those found for the radical anion of trimethylsilyl-benzene (111) [3] [7].…”

ESR.‐Messungen an Radikal‐Anionen Trimethylsilyl‐substituierter π‐Elektronensysteme

“…Die ESR.-Daten fur die Radikal-Anionen der mono-und bis-(Trimethylsily1)-substituierten Benzolderivate stiitzen den auf Grund fruherer Arbeiten [3] [4] vertretenen Standpunkt, dass die relative Energie der beidenin Benzol entartetenantibindenden hlOs yaund ya+ in diesen Verbindungen durch die konjugative Si + c,,-Elektronenruckgabe und nichtwie in den entsprechenden Alkylbenzolendurch den +I-Effekt bestimmt wird (vgl. z.…”