Chemistry-A European Journal Scheme2.Synthesis of cAAC-supported dimeric [((Cy-cAAC)P-K) 2 (THF) 4 (2a)] and hexameric [((Cy-cAAC)P-K) 6 (THF) 2 (3)] potassium-phosphinidenides. Scheme3.Syntheses of tetrameric [((Me 2-cAAC)P-K) 4 (THF) 4 (4)] potassiumand trimeric [((Cy-cAAC)P-Na) 3 (THF) (5)] sodium-phosphinidenides.

Syntheses of the copper and gold complexes [Cu{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] containing the homoleptic carbonyl cations [M{Fe(CO)5}2]+ (M=Cu, Au) are reported. Structural data of the rare, trimetallic Cu2Fe, Ag2Fe and Au2Fe complexes [Cu{Fe(CO)5}2][SbF6], [Ag{Fe(CO)5}2][SbF6] and [Au{Fe(CO)5}2][HOB{3,5‐(CF3)2C6H3}3] are also given. The silver and gold cations [M{Fe(CO)5}2]+ (M=Ag, Au) possess a nearly linear Fe‐M‐Fe’ moiety but the Fe‐Cu‐Fe’ in [Cu{Fe(CO)5}2][SbF6] exhibits a significant bending angle of 147° due to the strong interaction with the [SbF6]− anion. The Fe(CO)5 ligands adopt a distorted square‐pyramidal geometry in the cations [M{Fe(CO)5}2]+, with the basal CO groups inclined towards M. The geometry optimization with DFT methods of the cations [M{Fe(CO)5}2]+ (M=Cu, Ag, Au) gives equilibrium structures with linear Fe‐M‐Fe’ fragments and D2 symmetry for the copper and silver cations and D4d symmetry for the gold cation. There is nearly free rotation of the Fe(CO)5 ligands around the Fe‐M‐Fe’ axis. The calculated bond dissociation energies for the loss of both Fe(CO)5 ligands from the cations [M{Fe(CO)5}2]+ show the order M=Au (De=137.2 kcal mol−1)>Cu (De=109.0 kcal mol−1)>Ag (De=92.4 kcal mol−1). The QTAIM analysis shows bond paths and bond critical points for the M−Fe linkage but not between M and the CO ligands. The EDA‐NOCV calculations suggest that the [Fe(CO)5]→M+←[Fe(CO)5] donation is significantly stronger than the [Fe(CO)5]←M+→[Fe(CO)5] backdonation. Inspection of the pairwise orbital interactions identifies four contributions for the charge donation of the Fe(CO)5 ligands into the vacant (n)s and (n)p AOs of M+ and five components for the backdonation from the occupied (n‐1)d AOs of M+ into vacant ligand orbitals.

Sal fat, a nontraditional seed oil, was chemically modified to obtain base stocks with a wide range of specifications that can replace mineral oil base stocks. Sal fatty acids were enriched to 72.6% unsaturation using urea adduct method and reacted with branched mono alcohol, 2-ethylhexanol (2-EtH), and polyols namely neopentyl glycol (NPG) and trimethylolpropane (TMP) to obtain corresponding esters. The esters were hydroxylated and then acylated using propionic, butyric, and hexanoic anhydrides to obtain corresponding acylated derivatives. The acylated TMP esters exhibited very high viscosities (427.35-471.93 cSt at 40 °C) similar to those of BS 150 mineral oil base stock range, ISO VG 460, while the acylated NPG esters (268.81-318.84 cSt at 40 °C) and 2-EtH esters viscosities (20.94-24.44 cSt at 40 °C) exhibited viscosities in the range of ISO VG 320 and 22 respectively with good viscosity indices. Acylated NPG esters were found suitable for high temperature and acylated 2-ethylhexyl esters for low viscosity grade industrial applications. It was observed that the thermo-oxidative stabilities of all acylated products were found better compared to other vegetable oil based base stocks. Overall, all the sal fat based lubricant base stocks are promising candidates with a wide range of properties, which can replace most of the mineral oil base stocks with appropriate formulations.

A Schiff-base nickel­(II)-phosphene-catalyzed chemodivergent C–H functionalization and cyclopropanation of aromatic heterocycles is reported in moderate to excellent yields and very good regioselectivity and diastereoselectivity. The weak, noncovalent interaction between the phosphene ligand and Ni center facilitates the ligand dissociation, generating the electronically and coordinatively unsaturated active catalyst. The proposed mechanisms for the reported reactions are in good accord with the experimental results and theoretical calculations, providing a suitable model of stereocontrol for the cyclopropanation reaction.

The syntheses of the two novel complexes [Ag{Mo/W(CO)6}2]+[F‐{Al(ORF)3}2]− (RF=C(CF3)3) are reported along with their structural and spectroscopic characterization. The X‐ray structure shows that three carbonyl ligands from each M(CO)6 fragment bend towards the silver atom within binding Ag−C distance range. DFT calculations of the free cations [Ag{M(CO)6}2]+ (M=Cr, Mo, W) in the electronic singlet state give equilibrium structures with C2 symmetry with two bridging carbonyl groups from each hexacarbonyl ligand. Similar structures with C2 symmetry (M=Nb) and D2 symmetry (M=V, Ta) are calculated for the isoelectronic group 5 anions [Ag{M(CO)6}2]− (M=V, Nb, Ta). The electronic structure of the cations is analyzed with the QTAIM and EDA‐NOCV methods, which provide detailed information about the nature of the chemical bonds between Ag+ and the {M(CO)6}2q (q = −2, M = V, Nb, Ta; q = 0, M = Cr, Mo, W) ligands.