Themed collection Collection of articles dedicated to Professor David W. H. Rankin on the occasion of his retirement

Collision induced dissociation mass spectrometry shows that interactions in the outer sphere of monoanionic Cu(II)salicylaldoximato complexes greatly effects their gas phase stabilities.

The synthesis and structural characterisation of [BPh(bipy)] and [BCl(bipy)] are described both of which contain a direduced bipy ligand and are analogues of the fluorenyl anion; DFT calculations highlight differences in the electronic structure of both species compared to the fluorenyl anion.

Molecular 3d–4f cage complexes of {Cu₂₄Ln₈}, Ln = Dy, Gd and {Cu₁₆Ln₁₂} are reported. The metal ions in the cages are bridged by Ph₃C–PO₃²⁻, MeCO₂⁻, OH⁻ and NO₃⁻ units. Magnetic measurement of cage {Cu₂₄Dy₈} show single molecule magnet (SMM) behaviour while cage {Cu₂₄Gd₈} show large spin ground state, S_T = 34.

1,3-dialkylcarbodiimides insert into the Ae–X (Ae = Ca or Sr, X = NR₂, HNAr, PPh₂) bonds of a variety of homoleptic heavier alkaline earth species to yield the corresponding guanidinate and phosphaguanidinate complexes.

The first example of an “Arduengo-type” N-heterocyclic carbene supported by a BIAN ligand has been prepared and structurally authenticated. The preparation and X-ray crystal structures of the AgCl, AuCl, Ir(COD)Cl and Ir(CO)₂Cl complexes are also reported.

The Si₈O₁₂ cages of Si₈O₁₂(p-tolyl)₈ and Si₈O₁₂(p-ClCH₂C₆H₄)₈ in the crystalline phase are significantly distorted from the symmetry found for Si₈O₁₂Ph₈ in the gas phase.

A large interplanar angle between the benzazole and the N-aryl group of the title compounds correlates with a small angle between those of the N-aryl group and the substituent.

In keeping with experimental results, theoretical barrier heights for titanium alkoxides hydrolysis and condensation reactions, are substantially lower than those for silicon alkoxides.

Pressure induces a phase transition in [Gd(PhCOO)₃(DMF)]_n in which a stacking contact relieves strain built-up in short H⋯H contacts. The Gd⋯Gd distances increase to facilitate closer packing of the polymer chains.

The unusual X-ray-characterised Al and Sm β-diketiminates containing a reduced trianionic β-diketiminato ligand have been prepared via potassium reduction (Al) or a salt metathesis/disproportionation (Sm) route.

CO₂ insertion into a M–N bond (M = Li, Al) gives carbamato derivatives of the utility amide 2,2,6,6-tetramethylpiperidide. Salt metathesis of the Li derivative with the parent aluminium chloride provides an alternative route to the group 13 carbamate. The TMEDA solvated lithium carbamate and the unsolvated aluminium carbamate are both (MOCO)₂ dimers in the solid state.

Do molecules keep their shape in low-temperature matrices or not? The possibility of having both planar and pyramidal LnX₃ units in noble-gas matrices is indicated by matrix-isolation IR and Raman spectra and computations of DyI₃– a molecule that is planar in the gas phase.

The structures of P(C₂F₅)₃ determined in the solid and gaseous state, show it to have a preferred conformation with a sterically shielded binding site; this is expressed by a Tolman angle of ca. 191° (gas) and explains the greater difficulty to act as ligand towards metal atoms as compared to the slimmer P(CF₃)₃.

Re-analysis of earlier gas-phase electron diffraction (GED) studies of digallane in the light of new quantum chemical calculations affords the most realistic structure available to date. Matrix IR spectra at different temperatures give a first experimental estimate of the dissociation enthalpy of Ga₂H₆.

The tin(II) aminoalcoholate Sn(ttbap)₂ reacts with Fe₂(CO)₉ in 2 : 1 ratio (Sn : Fe = 1 : 1) to afford the donor–acceptor complex (ttbap)₂Sn:→Fe(CO)₄ retaining Sn(II), or in 1 : 1 ratio (Sn : Fe = 1 : 2) to give the Sn(0) complex (Httbap)Sn[Fe(CO)₄]₂, in which Httbap is a neutral zwitterionic form of the ligand.

We have performed ab initio MD simulations on (PH₃)₃MH₄ (M = Os, Ru and Fe) to quantify the effects of anharmonicity in refining diffraction data sets and interpreting vibrational spectra.

Five titanium arsine compounds have been synthesised from the reaction of TiCl₄ with (i) AsPh₃, (ii) 2AsPh₃, (iii) Ph₂AsCH₂AsPh₂, (iv) ^tBuAsH₂ and (v) As(NMe₂)₃. Typically 1 : 1 or 1 : 2 adducts were isolated however in the case of As(NMe₂)₃ an interesting Cl, NMe₂ group exchange occurred. The potential for these compounds to deposit TiAs via a single-source CVD route has been investigated.

4,1,6-, 4,1,8-, 4,1,10-, 4,1,12- and 4,1,2- isomers of 13-vertex indenyl cobaltacarboranes have been prepared and subjected to spectroscopic, structural, computational and electrochemical and related studies, with particular attention focused on the orientation of the indenyl ligand.

An efficient protocol for the first-principles computation of electric field gradients in transition metal complexes is presented.

The conformers of 1H-heptafluoropropane with HCCC dihedral angles gauche and anti. The anti form appears to have a dihedral angle of 180°, unlike longer fluoroalkane chains which exhibit helical twists.

While the equilibrium structure of ferrocene is eclipsed, D_5h, the equilibrium conformation of decachloroferrocene is staggered, D_5d; the barrier to internal rotation in the latter is only 0.8 kJ mol⁻¹, or about one fifth of the barrier in ferrocene.

Athough cyclopentadienylberyllium (CpBeH) is a carbon acid in the gas phase, both CpMgH and CpCaH are metal acids. Both compounds are stronger acids than CpBeH, and only slightly weaker acids than cyclopentadiene.

The structures of molecular tellurium tetrafluoride and tellurium tetrachloride were determined by a combination of gas-phase electron diffraction, mass spectrometry and quantum chemical calculations and compared to the structures of the molecules elucidated by X-ray diffraction of various solvates.

A new class of inorganic systems is introduced in which a silylene fragment is combined with a sulfur-nitrogen fragment. These new compounds are stable silylenes in which the sulfur-nitrogen fragment stabilizes both the singlet and the triplet states through electron delocalization.

New complexes of the above type are reported.

Spectroscopic studies of a dicopper(II) double helicate capable of encapsulating anions indicate that anion binding strength is dependent on the size and shape of the bound anion.

Chalcogen tetrahalides: trigonal bipyramidal or tetrahedral structure?

Nine new iron(III) cluster compounds assembled using salicylaldoxime derivatives range in nuclearity from three to twelve and include an unusual F-bridged square.

Highly accurate relativistic ab initio calculations show that the linear HePtF complex has a strong van der Waals He–Pt bond.

A series of homoleptic, four-coordinate guanidinato-lanthanide(II) complexes [Ln(Priso)₂] (see picture; Ar = 2,6-diisopropylphenyl, Cy = cyclohexyl) have been prepared and shown to exhibit coordination geometries midway between tetrahedral and planar. This contrasts with their bulkier analogues, [Ln(Giso)₂], which have previously been shown to display planar or distorted tetrahedral geometries.

Conformational preferences for PEt₃ and P(OMe)₃ ligands in their complexes are identified and analysed. The preferences arise from a combination of intra-ligand effects and the responses of the P-ligands to their environment. The phosphite is the more flexible ligand and pathways between conformers are visible.