Cover Picture: Exploring the Potential Energy Surface of E₂P₄ Clusters (E=Group 13 Element): The Quest for Inverse Carbon-Free Sandwiches (Chem. Eur. J. 16/2014)

Graphical Abstract

A viable alternative sandwich structure is presented, which does not contain any carbon atom. This D_4h-symmetric inverse sandwich instead uses the “carbon-like” phosphorus, which together with heavier elements of Group 13 (E = Al–Tl) forms a stable molecule. Density functional theory computations indicate that the sandwich form is more stable than a D_2d isomer of two perpendicular EP₂ units (except for E=B), and should be formed exothermically from white phosphorus and E₂. For more details, see the Full Paper by M. Swart, G. Merino et al. on page 4583 ff.

Cartoon 1

A viable alternative sandwich structure is presented, which does not contain any carbon atom. This D_4h-symmetric inverse sandwich instead uses the “carbon-like” phosphorus, which together with heavier elements of Group 13 (E = Al–Tl) forms a stable molecule. Density functional theory computations indicate that the sandwich form is more stable than a D_2d isomer of two perpendicular EP₂ units (except for E=B), and should be formed exothermically from white phosphorus and E₂. For more details, see the Full Paper by M. Swart, G. Merino et al. on page 4583 ff.

Ring-Expansion Reactions

3-Substituted piperidines are important building blocks for the preparation of many synthetic and natural biologically active compounds. In their Concept article on page 4516 ff., D. Gomez Pardo and J. Cossy provide an overview on the preparation of these compounds through the ring expansion of the corresponding prolinol derivatives, a transformation that proceeds via an aziridinium intermediate.1

Heteronuclear Metal String Complex

In their Communication on page 4526 ff., C.-h. Chen, S.-M. Peng, and I-C. Chen present the first hetero-pentametallic complex, [Ni⁺Ru₂⁵⁺Ni₂⁺Ni₂⁺(tripyridyldiamido)₄(NCS)₂], with a linear [NiRu₂Ni₂]¹⁰⁺ moiety helically wrapped by four ligands in the fashion of C₄ symmetry. The incorporation of a [Ru₂⁵⁺] unit results in a striking NDR behavior (negative differential resistance), one of the essential components in contemporary electronic and logic circuits. The energy-level analysis suggests that the NDR phenomenon is ascribed to the frontier molecular orbitals involving the diruthenium unit.1

Photoinduced Energy Transfer

A set of hybrids having gradual variation in distances between hexaphyrin and bodipy moieties was prepared. Efficient photoinduced energy transfer (PET) processes from bodipy to [26]/[28]hexaphyrin were successfully observed on terphenylene-containing hybrids. [26]-Hybrids performed slower decay/rise processes than [28]-hybrids on the basis of their enlarged center-to-center distances. These PET parameters were fairly consistent with calculated ones. More details can be found in the Full Paper by J.-Y. Shin, K. Kim, D. Kim, et al. on page 4574 ff.1