The kinetically robust hydride [t-HFe(Mepdt)(CO)(dppv)] ([t-H1]) (Mepdt = MeC(CHS); dppv = cis-1,2-CH(PPh)) and related derivatives were prepared with Fe enrichment for characterization by NMR, FT-IR, and NRVS. The experimental results were rationalized using DFT molecular modeling and spectral simulations. The spectroscopic analysis was aimed at supporting assignments of Fe-H vibrational spectra as they relate to recent measurements on [FeFe]-hydrogenase enzymes. The combination of bulky Mepdt and dppv ligands stabilizes the terminal hydride with respect to its isomerization to the 5-16 kcal/mol more stable bridging hydride ([μ-H1]) with t(313.3 K) = 19.3 min. In agreement with the nOe experiments, the calculations predict that one methyl group in [t-H1] interacts with the hydride with a computed CH···HFe distance of 1.7 Å. Although [t-H1] exhibits multiple NRVS features in the 720-800 cm region containing the bending Fe-H modes, the deuterated [t-D1] sample exhibits a unique Fe-D/CO band at ∼600 cm. In contrast, the NRVS spectra for [μ-H1] exhibit weaker bands near 670-700 cm produced by the Fe-H-Fe wagging modes coupled to Mepdt and dppv motions.
Here it is demonstrated that there is a linear relationship between the terminal 3d metal hydride stretching wavenumber ν and the metal hydride distance reported to date: ν ∼ (-1.05 + 3.35) × 10 cm.
Borohydride-based electrolytes have recently emerged as promising media for the electrodeposition of electropositive metals, including rare earth (RE) elements. While the presence of supporting alkali metal cations and RE counteranions provides essential electrochemical conductivity for achieving fast metal electrodeposition, interactions between the host ligand and solvated neodymium (Nd) complexes remain unclear. This study provides insights into the coordination structure of a concentrated and directly solvated Nd salt in a lithium borohydride-supported electrolyte.
The dimeric calcium and magnesium hydrides, [(BDI)AeH] [BDI=HC{(Me)CNDipp}, Dipp=2,6-i-PrCH; Ae=Mg or Ca] do not react with PhGeH in non-coordinating solvent. Addition of THF, however, induces deprotonation and access to monomeric Ae-germanide complexes, [(BDI)Ae{GePh}(THF)], both of which have been structurally characterized. Although this process is facile when Ae=Ca, the analogous magnesium-based reaction requires heating to temperatures >100 °C, under which conditions germanide formation is complicated by THF ring opening and the generation of an alkaline earth germyl-C-terminated n-butoxide, [(BDI)Mg{μ-O(CH)GePh}].
The molecular strontium hydride 2 [(Cbz)SrH(L)] (L=benzene, toluene) was isolated and stabilized by employing a sterically demanding carbazole ligand (Cbz=1,8-bis(3,5-ditertbutylphenyl)-3,6-ditertbutylcarbazolyl). Compound 2 was synthesized via phenylsilane metathesis with the corresponding amide (Cbz)SrN(SiMe) and characterized by H NMR, XRD and vibrational spectroscopy methods. We further investigated the stoichiometric reactivity of 2 towards carbon monoxide, azobenzene and trimethylsilylacetylene, showing three distinct reactivity pathways: addition, reduction and deprotonation.
This manuscript describes the synthesis of Os complexes supported by the diarylamido/bis(phosphine) PNP pincer ligand. Compound (PNP)OsH(CO) () was prepared by analogy with the previously reported . However, attempts to make (PNP)OsH () analogously to resulted in the formation of an unexpected compound () that is a product of addition of a BH unit across the Os-N bond in .
