Effect of exohedral functionalization on the magnetic properties in the dysprosium-containing endohedral fullerene DyScN@C(CF).

We present a quantum-chemical study of the effect of exohedral functionalization with a CF group on the lowest electronic states and the zero-field splitting pattern in a potential single-molecule magnet (SMM) compound DyScN@C(CF). Multiconfiguration perturbational methodology is applied to various spin states of the endohedral compound, comparing different active spaces and state-averaging schemes in order to check for the possible involvement of orbitals other than 4f-Dy in the nondynamical electronic correlation and to suggest the most appropriate computational parameters. Combining the spin-orbit coupling calculations with perturbational corrections, we demonstrate that the interactions within the endohedral cluster and with the fullerene cage exert only a small effect on the non-relativistic approximation to the electronic states of the Dy ion, yet they are significant enough to alter the parameters of zero-field splitting depending on the orientation of the DyScN cluster inside the fullerene cage.

/ photoisomerization pathway in pristine and fluorinated di(3-furyl)ethenes.

We report an XMCQDPT2 study of the / photoisomerization in a series of fluorinated di(3-furyl)ethenes (3DFEs). Upon excitation, pristine and low-fluorinated 3DFE show conventional behavior of many diarylethenes: unhindered twisting motion toward the pyramidalized zwitterionic state where relaxation to the ground state occurs. However, deep fluorination of 3DFEs can hamper -to- isomerization by giving rise to an alternative excited-state relaxation pathway: an out-of-plane motion of a ring fluorine atom.

Metallofullerene single-molecule magnet DyO@(5)-C with a strong antiferromagnetic Dy⋯Dy coupling.

Dysprosium-oxide clusterfullerene DyO@(5)-C is a single-molecule magnet featuring antiferromagnetic superexchange Dy⋯Dy coupling the μ-O bridge, the strongest of its kind among {Dy} complexes with non-radical bridges.

Substitution pattern dependent behavior of the singlet excited states in symmetrically fluorinated biphenyls.

Biphenyls are important basic chromophore systems that offer a possibility to study the effects of chemical substitution on the lower-lying excited states without complications from photoisomerization or other side processes. For several symmetric biphenyls, pristine biphenyl (bP0), 4,4'-difluorobiphenyl (bP2), 2,3,5,6,2',3',5',6'-octafluorobiphenyl (bP8), and perfluorobiphenyl (bP10), we report stationary and ultrafast solution-phase spectra rationalized with the aid of computations by means of the XMCQDPT2 multi-configuration perturbation theory and TDDFT. Polyfluorination tends to broaden the gap between the nearly degenerate S + S pair of states and the S state in bP8 and bP10, yet relaxation from any sheet of the S-S manifold leads through a system of state crossings to the same stationary points in S.

Shape-adaptive single-molecule magnetism and hysteresis up to 14 K in oxide clusterfullerenes DyO@C and DyO@C with fused pentagon pairs and flexible Dy-(μ-O)-Dy angle.

Dysprosium oxide clusterfullerenes DyO@C(10528)-C and DyO@C(13333)-C are synthesized and characterized by single-crystal X-ray diffraction. Carbon cages of both molecules feature two adjacent pentagon pairs. These pentalene units determine positions of endohedral Dy ions hence the shape of the DyO cluster, which is bent in DyO@C but linear in DyO@C.