Design, Development, and Testing of Machine Learning Models to Estimate Properties of Friction Stir Welded Joints.

This paper estimates friction stir welded joints' ultimate tensile strength (UTS) and hardness using six supervised machine learning models (viz., linear regression, support vector regression, decision tree regression, random forest regression, K-nearest neighbour, and artificial neural network). Tool traverse speed, tool rotational speed, pin diameter, shoulder diameter, tool offset, and tool tilt are the six input parameters in the 200 datasets for training and testing the models.

Solid/Gas Reactivity of an Ir(I) Methylidene Complex.

stabilization of known, but solution unstable, methylidene complex [Ir(Bu-PONOP)(=CH)][BAr ] allows single-crystal to single-crystal solid/gas reactivity associated with the {Ir=CH} group to be studied. Addition of H results in [Ir(Bu-PONOP)(H)][BAr ]; exposure to CO forms iridium(I) carbonyl [Ir(Bu-PONOP)(CO)][BAr ], and reaction with NH gas results in the formation of methylamine complex [(Bu-PONOP)Ir(NHMe)][BAr ] via an aminocarbene intermediate. Periodic density functional theory and electronic structure analyses confirm the Ir=CH bond character but with a very low barrier to rotation around the Ir=CH bond.

A Gold(I)-Acetylene Complex Synthesised using Single-Crystal Reactivity.

Using single-crystal to single-crystal solid/gas reactivity the gold(I) acetylene complex [Au(L1)(η-HC≡CH)][BAr ] is cleanly synthesized by addition of acetylene gas to single crystals of [Au(L1)(CO)][BAr ] [L1=tris-2-(4,4'-di-tert-butylbiphenyl)phosphine, Ar=3,5-(CF)CH]. This simplest gold-alkyne complex has been characterized by single crystal X-ray diffraction, solution and solid-state NMR spectroscopy and periodic DFT. Bonding of HC≡CH with [Au(L1)] comprises both σ-donation and π-backdonation with additional dispersion interactions within the cavity-shaped phosphine.

lattice adaptivity triggered by solid-gas reactions of cationic group 7 pincer complexes.

The group 7 complexes [M(κ-2,6-(RPO)CHN)(CO)L][BAr] [M = Mn, R = Pr, L = THF; M = Re, R = Bu, L = vacant site] undergo solid-gas reactivity with CO to form the products of THF substitution or CO addition respectively. There is a large, local, adaptive change of [BAr] anions for M = Mn, whereas for M = Re the changes are smaller and also remote to the site of reactivity.

A comparison of non-covalent interactions in the crystal structures of two σ-alkane complexes of Rh exhibiting contrasting stabilities in the solid state.

Non-covalent interactions surrounding the cationic Rh σ-alkane complexes within the crystal structures of [(CyPCHCHPCy)Rh(NBA)][BAr], [1-NBA][BArF4] (NBA = norbornane, CH; Ar = 3,5-(CF)CH), and [1-propane][BArF4] are analysed using Quantum Theory of Atoms in Molecules (QTAIM) and Independent Gradient Model approaches, the latter under a Hirshfeld partitioning scheme (IGMH). In both structures the cations reside in an octahedral array of [BAr] anions within which the [1-NBA]+ cation system exhibits a greater number of C-H⋯F contacts to the anions. QTAIM and IGMH analyses indicate these include the strongest individual atom-atom non-covalent interactions between the cation and the anion in these systems.

Chasing the agostic interaction in ligand assisted cyclometallation reactions of palladium(ii).

A 500 MHz NMR study of the reaction between 1-tetralone oxime and PdCl in CDOD shows resonances attributable to a potential agostic intermediate prior to the formation of the insoluble cyclopalladated product which itself was characterised by X-ray crystallography. Calculated structural, spectroscopic, QTAIM, NBO and NCI analysis results obtained from density functional theory (DFT) calculations give a full description of the putative agostic intermediate [PdCl(1-tetralone oxime)] (1) which is shown to include a previously unrecognised π-electron density donation from the aromatic ring to the metal in close proximity to the agostic carbon atom. Changing the (N)-OH donor to (N)-OMe does not effect the magnitude of these interactions.

New complexity for aromatic ring agostic interactions.

Density functional theory (DFT) calculations reveal that for ligand directed aromatic ring C-H bond activation, the agostic donation can share the same antibonding acceptor orbitals as a previously unrecognised π-donation from the aromatic ring of the ligand. The recognition of carbon based orbitals assisting the agostic interaction has significant implication for C-H bond activation chemistry.

4-Methyl-N-(4-methyl-phen-yl)benzene-sulfonamide.

In the title compound, C(14)H(15)NO(2)S, the two aromatic rings enclose a dihedral angle of 70.53 (10)°. A weak intra-molecular C-H⋯O hydrogen bond generates an S(6) ring motif.