Insights into the decomposition pathway of a lutetium alkylamido complex via intramolecular C–H bond activation

Synthesis, characterization and reaction chemistry of lutetium alkylamido LLu(CH2SiMe3)(NHCPh3) (2), L = 2,5-[Ph2P=N(4-iPrC6H4)]2N(C4H2)–, is reported. Complex 2 undergoes cyclometalation of the NHCPh3 ligand at elevated temperatures to produce the orthometalated complex LLu(κ2−N,C-(NHCPh2(C6H4))) (3) which converts to 0.5 equivalents of bis(amido) LLu(NHCPh3)2 (4) upon heating at 80 °C for 24 h. Reaction of complex 2 with 4-dimethylaminopyridine (DMAP) does not promote alkane elimination nor imido formation. A kinetic analysis of the thermal decomposition of complex 2, supported by deuterium labelling studies and computational analysis (PBE0/def2-TZVP/SDD(Lu)), indicate direct Csp2–H activ…

Tasaväli-integraali

Strong N−X···O−N Halogen Bonds: Comprehensive Study on N‐Halosaccharin Pyridine N‐oxide Complexes

A detailed study of the strong N−X⋯−O−N+ (X = I, Br) halogen bonding interactions in solution and in the solid‐state reports 2×27 donor×acceptor complexes of N‐halosaccharins and pyridine N‐oxides (PyNO). Density Functional Theory (DFT) calculations were used to investigate the X···O halogen bond (XB) interaction energies in 54 complexes. The XB interaction energies were found to vary from –47.5 to –120.3 kJ mol–1, with the strongest N−I⋯−O−N+ XBs approaching those of 3‐center‐4‐electron [N–I–N]+ halogen‐bonded systems (∼160 kJ mol–1). Using a subset of 32 complexes, stabilized only through N−X···−O−N+ XB interactions, a simplified, computationally fast, electrostatic model to predict the X…

Benson group additivity values of phosphines and phosphine oxides : Fast and accurate computational thermochemistry of organophosphorus species

Composite quantum chemical methods W1X-1 and CBS-QB3 are used to calculate the gas phase standard enthalpy of formation, entropy and heat capacity of 38 phosphines and phosphine oxides for which reliable experimental thermochemical information is limited or simply nonexistent. For alkyl phosphines and phosphine oxides, the W1X-1 and CBS-QB3 results are mutually consistent and in excellent agreement with available G3X values and empirical data. In the case of aryl-substituted species, different computational methods show more variation, with G3X enthalpies being furthest from experimental values. The calculated thermochemical data are subsequently used to determine Benson group additivity co…

77Se NMR Spectroscopic, DFT MO, and VBT Investigations of the Reversible Dissociation of Solid (Se6I2)[AsF6]2•2SO2 in Liquid SO2 to Solutions Containing 1,4-Se6I22+ in Equilibrium with Sen2+ (n = 4, 8, 10) and Seven Binary Selenium Iodine Cations: Preliminary Evidence for 1,1,4,4-Se4Br42+ and cyclo-Se7Br+

The composition of a complex equilibrium mixture formed upon dissolution of (Se6I2)[AsF6]2·2SO2 in SO2(l) was studied by 77Se NMR spectroscopy at −70 °C with both natural-abundance and enriched 77Se-isotope samples (enrichment 92%). Both the natural-abundance and enriched NMR spectra showed the presence of previously known cations 1,4-Se6I22+, SeI3+, 1,1,4,4-Se4I42+, Se102+, Se82+, and Se42+. The structure and bonding in 1,4-Se6I22+ and 1,1,4,4-Se4I42+ were explored using DFT calculations. It was shown that the observed Se−Se bond alternation and presence of thermodynamically stable 4pπ−4pπ Se−Se and 4pπ−5pπ Se−I bonds arise from positive charge delocalization from the formally positively c…

A Selenium-Nitrogen Chain with Selenium in Different Oxidation States

The reaction of tBuNH2 with a mixture of SeCl2 and SeOCl2 in a 6:2:1 molar ratio produces the novel selenium-nitrogen chain ClSeN(tBu)Se(O)Cl (4), in which the selenium atoms are in two different oxidation states, SeII and SeIV. The crystal structure of 4 is compared with that of the related SeII/SeII system ClSeN(tBu)SeCl (1) and differences are attributed to hyperconjugative effects. The energetics of the formation of 4 via two different routes are elucidated by PBE0/def2-TZVPP calculations. peerReviewed

Tridentate C–I⋯O−–N+ halogen bonds

The X-ray structures of the first co-crystals where the three oxygen lone pairs in N-oxides are fully utilized for tridentate C–I⋯O−–N+ halogen bonding with 1,ω-diiodoperfluoroalkanes are reported, studied computationally, and compared with the corresponding silver(I) N-oxide complexes. peerReviewed

Synthesis, Characterization, and Properties of Weakly Coordinating Anions Based on tris-Perfluoro-tert-Butoxyborane

Abstract Image A convenient method for the preparation of strongly Lewis acidic tris-perfluoro-tert-butoxyborane B(ORF)3 (1), (ORF = OC(CF3)3) was developed, and its X-ray structure was determined. 1 was used as a precursor, guided by density functional theory (DFT) calculations and volume-based thermodynamics, for the synthesis of [NEt4][NCB(ORF)3] (3) and [NMe4][FB(ORF)3] (5) and the novel large and weakly coordinating anion salts [Li 15-Crown-5][B(ORF)4] (2) and [NEt4][CN{B(ORF)3}2] (4). The stability of [B(ORF)4]− was compared with that of some related known weakly coordinating anions by appropriate DFT calculations. peerReviewed