Adamantane-type clusters: compounds with a ubiquitous architecture but a wide variety of compositions and unexpected materials properties

The research into adamantane-type compounds has gained momentum in recent years, yielding remarkable new applications for this class of materials. In particular, organic adamantane derivatives (AdR4) or inorganic adamantane-type compounds of the general formula [(RT)4E6] (R: organic substituent; T: group 14 atom C, Si, Ge, Sn; E: chalcogenide atom S, Se, Te, or CH2) were shown to exhibit strong nonlinear optical (NLO) properties, either second-harmonic generation (SHG) or an unprecedented type of highly-directed white-light generation (WLG) - depending on their respective crystalline or amorphous nature. The (missing) crystallinity, as well as the maximum wavelengths of the optical transitions, are controlled by the clusters' elemental composition and by the nature of the organic groups R. Very recently, it has been additionally shown that cluster cores with increased inhomogeneity, like the one in compounds [RSi{CH2Sn(E)R'}3], not only affect the chemical properties, such as increased robustness and reversible melting behaviour, but that such 'cluster glasses' form a conceptually new basis for their use in light conversion devices. These findings are likely only the tip of the iceberg, as beside elemental combinations including group 14 and group 16 elements, many more adamantane-type clusters (on the one hand) and related architectures representing extensions of adamantane-type clusters (on the other hand) are known, but have not yet been addressed in terms of their opto-electronic properties. In this review, we therefore present a survey of all known classes of adanmantane-type compounds and their respective synthetic access as well as their optical properties, if reported.

Effect of stepwise protonation of an N-containing ligand on the formation of metal–organic salts and coordination complexes in the solid state

Controlled synthesis of a series of metal–organic salts and coordination complexes is tuned by the protonation of ligand, and their transformations are induced by the solid–gas and concentration of [H⁺].

Fluorescence-based detection of nitroaromatics using a luminescent second sphere adduct self-assembled by charge-assisted hydrogen bonds

Photo-luminescent metal organic materials self-assembled via second sphere coordination using luminescent ligands show good selectivity to detect trace amounts of nitroaromatics.

Insights into the electron-donating and withdrawing effect of the functional groups on mechanochemical dehydrochlorination reactions

The effect on electron depletion in a partially fluorinated ligand has been evaluated in a dehydrochlorination reaction by converting outer sphere adducts into a coordination complex using experimental and DFT data.

Chelate ring stacking interactions in the supramolecular assemblies of Zn(ii)and Cd(ii) coordination compounds: a combined experimental and theoretical study

We report seven Zn(ii)/Cd(ii) complexes with picolinoyl/isonicotinoyl hydrazone based ligands exhibiting relevant chelate–π interactions.

Insights into the formation of chiral second sphere coordination complexes with aromatic tris amines: combined single crystal X-ray crystallography and molecular modeling analyses

Bulky methyl groups on the central aromatic ring in chiral isostructural second sphere coordination adducts are crucial for the induction of chirality.

A second sphere coordination adduct containing one-dimensional water/methanol channels: X-ray structures, thermal stability and single crystal impedance spectroscopy analysis

The X-ray structures, thermal stability, guest behavior and impedance spectroscopy analysis of a second sphere adduct are reported.