An Isolable Phosphinogermylyne as a Synthon of One‐Coordinate GeI Radical

Abstract

Comprehensive SummaryReduction of chlorogermylene MsFluindtBu‐GeCl 1 with potassium graphite (KC8) afforded putative germylyne radical MsFluindtBu‐Ge 2 as confirmed by electron paramagnetic resonance (EPR) spectroscopy. However, it slowly decayed via C—H bond activation at the fluorenyl moiety to yield a bis(germylene) 3 at room temperature. By using a Lewis base to stabilize the unoccupied p orbital at the GeI radical center, acyclic two‐coordinate GeI radicals MsFluindtBu‐Ge(IMe4) 4 (IMe4 = 1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene), MsFluindtBu‐Ge(IiPr) 5 (IiPr = 1,3‐diisopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene), MsFluindtBu‐Ge(PMe3) 6 were isolated in crystalline forms. The unpaired electron in 4—6 mainly resides at the Ge 4p orbital as revealed by EPR spectroscopic studies and theoretical calculations. Interestingly, facile ligand exchange of PMe3 in 6 with IMe4 and IiPr was observed to afford 4 and 5, respectively. Moreover, phosphinogermylyne 6 reacted with PhEEPh (E = S, Se), 4‐tetrabutylphenylacetylene (Ar'CCH), [CpMo(CO)3]2 and nBu3SnH to furnish germylenes MsFluindtBu‐GeEPh (E = S 7, Se 8), MsFluindtBu‐GeCH=CHAr’ 9, a germylyne complex MsFluindtBu‐Ge≡Mo(CO)2Cp 10 and a Ge(IV) compound MsFluindtBu‐GeH2SnnBu3 11, respectively. The reactivity studies demonstrate that 6 can act as a synthon of one‐coordinate germylyne radical attributing to labile coordination of trimethylphosphine.