An Isolable Phosphinogermylyne as a Synthon of <scp>One‐Coordinate Ge<sup>I</sup></scp> Radical
Dongmin Wang, Haonan Chen, Yuhao He, Xiaodan Chen, Li Zhang, Gengwen Tan
Abstract
Comprehensive Summary Reduction of chlorogermylene M s Fluind t Bu ‐GeCl 1 with potassium graphite (KC 8 ) afforded putative germylyne radical M s Fluind t Bu ‐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 Ge I radical center, acyclic two‐coordinate Ge I radicals M s Fluind t Bu ‐Ge(I Me4 ) 4 (I Me4 = 1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene), M s Fluind t Bu ‐Ge(I i Pr ) 5 (I i Pr = 1,3‐diisopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene), M s Fluind t Bu ‐Ge(PMe 3 ) 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 PMe 3 in 6 with I Me4 and I i Pr 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 n Bu 3 SnH to furnish germylenes M s Fluind t Bu ‐GeEPh (E = S 7 , Se 8 ), M s Fluind t Bu ‐GeCH=CHAr’ 9 , a germylyne complex M s Fluind t Bu ‐Ge≡Mo(CO) 2 Cp 10 and a Ge(IV) compound M s Fluind t Bu ‐GeH 2 Sn n Bu 3 11 , respectively. The reactivity studies demonstrate that 6 can act as a synthon of one‐coordinate germylyne radical attributing to labile coordination of trimethylphosphine.