Frustrated Lewis Pair Chelation as a Vehicle for Low‐Temperature Semiconductor Element and Polymer Deposition

Abstract

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).

New cationic coinage metal complexes featuring silyl group functionalized phosphine: syntheses, structures and catalytic studies in alkyne–azide cycloaddition reactions

“…S64, † the 1 : 1 : 1 reaction of benzyl azide, phenylacetylene, and cat. 3 in an NMR tube clearly showed the progression of the reaction toward the anticipated cyclization reaction to give the triazole 5), and C6-C7 1.456 (6).…”

“…As shown in Chart 1, group 13 and 14 element substituted phosphines of types I and II were isolated and used in both main group and transition metal chemistry. Among these two classes of phosphines, type I was introduced recently; 6–8 however, species of type II (R = Me, Cl, H) were isolated several years ago. 9–11 Type II phosphines consisting of ortho -silylated groups and their transition metal complexes have been shown to exhibit enhanced solubility in various non-polar solvents which is in contrast to many typical aryl phosphine ligands.…”

“…In a similar fashion, Shi and co-workers demonstrated the isolation of gold (I) chloride complexes of type III. 11 In view of the general interest, various phosphines functionalized with group 13 6,7,16 and 14 element-containing groups (as Lewis acidic moieties) as monodentate ligands 17 have not been studied extensively in transition metal organometallic chemistry and homogeneous catalysis as in the case of their pincer counterparts (PSiP). 2,3,18 Their transition metal chemistry is still in its infancy.…”

NHC‐Stabilized Mixed Group 13/14/15 Element Hydrides

“…Also, Inoue reported on an alternative synthetic strategy resulting in the formation of III , which was obtained by the reaction of IMe 4 ⋅ SiHSi t Bu 3 (IMe 4 =1,3,4,5‐tetra(methyl)imidazol‐2‐ylidene) with H 3 N ⋅ BH 3 by dehydrogenation to H 2 NBH 2 and subsequent insertion/rearrangement processes [7] . Furthermore, two very recent examples of heterocycles that include group 13/14/15 element‐based building blocks are: IV , [8] reported by Kinjo, and the Frustrated Lewis Pair (FLP)‐stabilized adducts V , synthesized by the Rivard group; notably, compounds V can be used as precursors for the low‐temperature deposition (<100 °C) of elemental Si and Ge films from solution [9] . A rare example of a heterocycle that consists exclusively of combinations of group 13, group 14 (Tet≠C) and group 15 elements is VI , reported by Nöth; however, the characterization of VI was limited to NMR spectroscopy [10] .…”