The protonation of metal hydrides

Transformation of organic molecules on the low‐valent {M(Ph2PCH2CH2PPh2)2} moiety derived from trans‐[M(N2)2(Ph2PCH2CH2PPh2)2] or related complexes (M = MO, W)

“…Treatment of 24 with HBF 4 or TfOH (Tf = CF 3 SO 2 ) leads to the oxidation of the metal center to form the M(II) complexes trans ‐[MF(η 2 ‐HC≡CH)(dppe) 2 ][BF 4 ] ( 25 ) or trans ‐[M(OH)(η 2 ‐HC≡CH)(dppe) 2 ][OTf] ( 26 ), respectively, which can also be prepared by oxidation of 24 with two equiv of [Cp 2 Fe]X (X = BF 4 , OTf). As observed previously for the analogous alkyne complex trans ‐[MoF(η 2 ‐PhC≡CH)(dppe) 2 ][BF 4 ] prepared from 2a and phenylacetylene in the presence of HBF 4 ·OEt 2 ,59–60 25 and 26 contain the acetylene ligand as a four‐electron donor. In contrast, in the reaction of 24a with HBF 4 or TfOH in the presence of DMF, the ethylidyne complexes trans ‐[MoF(≡CCH 3 )(dppe) 2 ] ( 27 ) and trans ‐[Mo(≡CCH 3 )(DMF)(dppe) 2 ][OTf] ( 28 ) are obtained; the analogous reaction of 24b with TfOH/DMF forms trans ‐[WH(η 2 ‐HC≡CH)(dppe) 2 ][OTf] ( 29 ) through monoprotonation at the metal.…”

“…UV irradiation of 2a in benzene under CO 2 leads to the formation of the hydrido‐formato complex [MoH(η 2 ‐O 2 CH)(dppe) 2 ] ( 61 ) via the insertion of CO 2 into the Mo–H bond (Scheme ) 107. In the presence of HBF 4 ·OEt 2 , 2a reacts with CO 2 to form the dihydrido‐formato complex [MoH 2 (η 2 ‐O 2 CH)(dppe) 2 ][BF 4 ] ( 62 ) 59, 60…”

Protonation Behavior of a Tetrahydrido Molybdenum(IV) Complex with Organic and Inorganic Acids

“…Unambiguous determination of the number of hydride ligands was possible by 31 P NMR spectroscopy: the singlet observed at 73.8 ppm in broad-band 1 H-decoupled spectrum splits into a sextet upon selective decoupling of the aliphatic protons ( 2 J (PÀ H) = 30.6 Hz, see Supplementary Information). 11 B NMR and 19 F NMR spectra are typical of HB(C 6 F 5 ) 3…”

“…[MoH 4 (depe) 2 ] [8c] and [tBu 3 PH][HB(C 6 F 5 ) 3 ] [16] were synthesized according to reported procedures and stored in the glove box. 1 H, 11 B, 19 F and 31 P NMR spectra were recorded in C 6 D 6 or THF-d 8 by using Wilmad quick pressure valve NMR tubes or J. Young high-vacuum valve NMR tubes on a Bruker Avance III 400 spectrometer.…”

“…The behavior of some of those derivatives has previously been investigated towards acids. As examples, stopped‐flow monitoring of the reaction of [MoH 4 (dppe) 2 ] [10] (dppe=1,2‐bis(diphenylphosphino)ethane) or [WH 4 (PMePh 2 ) 4 ] [11] with HCl allowed the group of Henderson to suggest the existence of elusive σ‐H 2 complexes en route to a spectroscopically‐identified cationic pentahydride. UV‐Vis and IR spectroscopies were used by the group of Shubina to evidence that protonation of the complex [WH 4 (dppe) 2 ] was occurring through the assistance of unusual, but rather strong, hydrogen bonds [12] .…”