Reactions of silanes and germanes with iridium complexes. Part 2. Adducts of silyl and germyl halides and related molecules with trans-carbonylhalogenobis(triethylphosphine)iridium(I)

Oxidative addition of SiH4and GeH4to Ir(PPh3)2(CO)Cl: structural and spectroscopic evidence for the formation of products derived from cis oxidative addition

“…7 However, while there are numerous studies concerned with the reactivity of substituted silanes towards metal centers, the reactivity of the parent silane, SiH 4 , has received relatively little attention. [8][9][10][11][12][13][14][15] Therefore, we describe here the reaction between SiH 4 and Vaska's compound, Ir(PPh 3 ) 2 (CO)Cl, and demonstrate that the SiH 3 and H ligands in the product adopt a cis disposition, in which H is located trans to CO, rather than trans to Cl as originally reported.…”

“…1). 13 However, despite the significantly different structure proposed for Ir(PEt 3 ) 2 (CO)(Cl)(SiH 3 )H, the NMR data pertaining to the [Ir(SiH 3 )H] moiety of this compound bear distinct similarities to those of Ir(PPh 3 ) 2 (CO)(Cl)(SiH 3 )H (Tables 2 and 3). Specifically, the 1 H NMR spectrum of Ir(PEt 3 ) 2 (CO)(Cl)(SiH 3 )H exhibits signals attributable to the SiH 3 ligand at δ 2.9 and the hydride ligand at δ −8.1, both of which exhibit triplet coupling to the two phosphorus nuclei and mutual coupling to each other.…”

“…Previous studies have demonstrated that Ir(PPh 3 ) 2 (CO)Cl and its derivatives are capable of undergoing the oxidative addition of a Si-H bond in a variety of silanes, 12,13,[16][17][18][19] as illustrated in Scheme 1 for the reaction with SiH 4 .…”

Photochemical Oxidative Addition of Germane and Diphenylgermane to Ruthenium Dihydride Complexes

“…9 In pioneering work, the thermal reactions of Ir(PEt3)2X(CO) (X = Cl, I) with SiH4 and GeH4 were shown to afford oxidative addition products IrH(EH3)(PEt3)2(X)(CO) (E = Si, Ge). 10 In 2015, the reaction of Vaska's complex Ir(PPh3)2(CO)Cl with SiH4 and GeH4 was examined. 11 A combination of Xray structure analysis of the SiH4 oxidative addition product and NMR spectroscopy led to assignments of these products and reassignment of the geometries of the earlier PEt3 complexes (Scheme 1).…”

“…Scheme 1. Products of reaction of Ir(PR3)2(CO)Cl with SiH4 and GeH4 (R = Ph, Et) 10,11 Comparison of the reactivity of agostic Mo(CO)(PP)2 (PP = R2PCH2CH2PR2; R = Ph dppe, R = Et depe) toward silane and germane revealed the  2 -coordination product Mo(CO)(PP)2( 2 -SiH4) for R = Ph, i Bu, whereas a mixture of oxidative addition and  2 -SiH4 products was obtained for R = Et. 12,13 Formation of the  2 -GeH4 complex Mo(CO)(dppe)2( 2 -GeH4) was demonstrated by IR and NMR spectroscopy, while the analogue with R = Et was shown to adopt a germyl hydride structure Mo(CO)(depe)2(GeH3)H. 13 Further studies (see below) established a general trend in which oxidative addition is favored thermodynamically over  2 -coordination in the order Ge-H > Si-H  H-H >> C-H for these Mo complexes.…”