Browsing by Subject "Density functional calculations"
Now showing items 1-2 of 2
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(2020)The reaction of the intramolecular frustrated Lewis pair (FLP) tBu2PCH2BPh2 with the amine-boranes NH3·BH3 and Me2NH·BH3 leads to the formation of the corresponding FLP-H2 adducts as well as novel five-membered heterocycles that result from capturing the in situ formed amino-borane by a second equivalent of FLP. The sterically more demanding tBu2PCH2BMes2 does not form such a five-membered heterocycle when reacted with Me2NH·BH3 and its H2 adduct liberates dihydrogen at elevated temperatures, promoting the metal-free catalytic dehydrogenation of amine-boranes.
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(2019)Calculations have been performed at the MP2 and DFT levels for investigating the reasons for the difficulties in synthesizing bis(isocyanide)gold(I) halide complexes. Three-coordinated gold(I) complexes of the type (R3P)(2)(AuX)-X-I (1) can be synthesized, whereas the analogous isocyanide complexes (RNC)(2)(AuX)-X-I (2) are not experimentally known. The molecular structures of (R3P)(2)(AuX)-X-I (X = Cl, Br, and I) and (RNC)(2)(AuX)-X-I with X = halide, cyanide, nitrite, methylthiolate, and thiocyanate are compared and structural differences are discussed. Calculations of molecular properties elucidate which factors determine the strength of the gold-ligand interactions in (RNC)(2)(AuX)-X-I. The linear bonding mode of RNC favors a T-shaped geometry instead of the planar Y-shaped trigonal structure of (R3P)(2)(AuX)-X-I complexes that have been synthesized. An increased polarity of the Au-X bond in 2 leads to destabilization of the Y-shaped structure. Chalcogen-containing ligands or cyanide appear to be good X-ligand candidates for synthesis of (RNC)(2)(AuX)-X-I complexes.
