The stabilization of silicon(II) and germanium(II) dihydrides by an intramolecular Frustrated Lewis Pair (FLP) ligand, PB, i Pr 2 P(C 6 H 4)BCy 2 (Cy = cyclohexyl) is reported. The resulting hydride complexes [PB{SiH 2 }] and [PB{GeH 2 }] are indefinitely stable at room temperature, yet can deposit films of silicon and germanium, respectively, upon mild thermolysis in solution. Hallmarks of this work include: 1) the ability to recycle the FLP phosphine-borane ligand (PB) after element deposition, and 2) the single-source precursor [PB{SiH 2 }] deposits Si films at a record low temperature from solution (110 8C). The dialkylsilicon(II) adduct [PB{SiMe 2 }] was also prepared, and shown to release poly(dimethylsilane) [SiMe 2 ] n upon heating. Overall, this study introduces a "closed loop" deposition strategy for semiconductors that steers materials science away from the use of harsh reagents or high temperatures. Scheme 1. General concept of FLP-assisted semiconductor (E) and polymer [ER 2 ] n deposition (E = Si, Ge).

The stabilization of silicon(II) and germanium(II) dihydrides by an intramolecular Frustrated Lewis Pair (FLP) ligand, PB, i Pr 2 P(C 6 H 4)BCy 2 (Cy = cyclohexyl) is reported. The resulting hydride complexes [PB{SiH 2 }] and [PB{GeH 2 }] are indefinitely stable at room temperature, yet can deposit films of silicon and germanium, respectively, upon mild thermolysis in solution. Hallmarks of this work include: 1) the ability to recycle the FLP phosphine-borane ligand (PB) after element deposition, and 2) the single-source precursor [PB{SiH 2 }] deposits Si films at a record low temperature from solution (110 8C). The dialkylsilicon(II) adduct [PB{SiMe 2 }] was also prepared, and shown to release poly(dimethylsilane) [SiMe 2 ] n upon heating. Overall, this study introduces a "closed loop" deposition strategy for semiconductors that steers materials science away from the use of harsh reagents or high temperatures. Scheme 1. General concept of FLP-assisted semiconductor (E) and polymer [ER 2 ] n deposition (E = Si, Ge).