Two new sandwich calix[4]arene-supported cluster complexes, [Ln4(OH)4(TBSOC)2(H2O)4(CH3OH)4]·4H2O (H4TBSOC = p-tert-butylsulfonylcalix[4]arene; Ln = Dy, 1; Ln = Ho, 2), have been prepared and characterized. An X-ray crystallographic study reveals that both complexes contain a holistically disordered [Ln4(OH)4]8+ cubane cluster core, which is sandwiched between two antiparallel calixarene macrocycles. Magnetic investigations indicate that complex 1 displays slow magnetization relaxation typical for single-molecule magnets in the absence of a static applied dc field, with the ΔE/kB parameter of 22.9 K, the largest value for the calixarene-supported pure 4f single-molecule magnets so far, whereas complex 2 does not show any relaxation of the magnetization above 2 K.

Syntheses, Crystal Structures, and Magnetic Properties of Two p-tert-Butylsulfonylcalix[4]arene Supported Cluster Complexes with a Totally Disordered Ln4(OH)4 Cubane Core

The single-crystal X-ray structure of Ru3(CO)12 is reported at 8 pressures ranging from 1 atm (0.0 GPa) to 8.14(5) GPa. Although intramolecular bonding parameters remain relatively constant, intramolecular and intermolecular nonbonding contact distances decrease by an average of 4% and 15%, respectively. At 8.14 GPa, O···O, C···O, and C···C intermolecular distances as short as 2.54(4), 2.64(6), and 3.07(4) A, respectively, are observed, and the unit cell compresses to 75% of the ambient pressure volume. Raman and infrared spectroscopic measurements show that carbonyl stretching frequencies shift to higher wavenumber values by as much as 80 cm-1, even though Ru−C and C−O distances stay roughly constant throughout the entire pressure range studied. Compression of the sample to above 18 GPa with laser radiation results in an irreversible transformation due to either decomposition or a total collapse of D3h molecular geometry accompanied by color darkening.

High Pressure Study of Ru3(CO)12 by X-ray Diffraction, Raman, and Infrared Spectroscopy

The applicability of several popular density functionals in predicting the geometrical parameters and energetics of transition metal carbonyl complexes of iron, ruthenium and osmium has been studied. The methods tested include pure GGA functionals (BLYP, BP86, OPBE, HCTH, PBE, VSXC) and hybrid GGA functionals (B3PW91, B3LYP, PBE1PBE, MPW1K, B97-2, B1B95, PBE1KCIS). The effect of changing the metal basis set from Huzinaga’s all-electron basis to SDD scECP basis was also studied. The results show, that hybrid functionals are needed in order to describe the back-bonding ability of the carbonyl ligands as well as to deal with metal-metal bonds. The best general performance, when also the computational cost was considered, was obtained with hybrid functionals B3PW91 and PBE1PBE, which therefore provide an efficient tool for solving problems involving large or medium sized transition metal carbonyl compounds.

DFT tests for group 8 transition metal carbonyl complexes.

QTAIM View of Metal–Metal Bonding in Di- and Trinuclear Disulfido Carbonyl Clusters

Herein is reported the synthesis, by a solid-state reaction from [Ir(NBD)2(PiPr3)][BArF4], of the first example of a C–C σ-complex with iridium, [Ir(BINOR-S)(PiPr3)][BArF4]. This compound is unique in that in the solid state it undergoes reversible activation of the C–C single bond that interacts with the metal center, establishing a temperature-dependent equilibrium between Ir(III) C–C σ/Ir(V) bis-alkyl complexes. This process has been interrogated by variable-temperature X-ray diffraction, NMR spectroscopy, and DFT calculations.

C-C activation in the solid state in an organometallic σ-complex.

Dynamic Disorder and Fluxionality in M3(CO)12 Clusters: Variable-Temperature X-ray Diffraction Studies on FenRu3-n(CO)12 (n = 1, 2) and the Low-Temperature Phase of Fe3(CO)12

Amy L. Gillon

Papers

Dynamic Disorder and Fluxionality in M3(CO)12 Clusters: Variable-Temperature X-ray Diffraction Studies on FenRu3-n(CO)12 (n = 1, 2) and the Low-Temperature Phase of Fe3(CO)12