This review captures the synthesis, assembly, properties, and applications of copper chalcogenide NCs, which have achieved significant research interest in the last decade due to their compositional and structural versatility. The outstanding functional properties of these materials stems from the relationship between their band structure and defect concentration, including charge carrier concentration and electronic conductivity character, which consequently affects their optoelectronic, optical, and plasmonic properties. This, combined with several metastable crystal phases and stoichiometries and the low energy of formation of defects, makes the reproducible synthesis of these materials, with tunable parameters, remarkable. Further to this, the review captures the progress of the hierarchical assembly of these NCs, which bridges the link between their discrete and collective properties. Their ubiquitous application set has cross-cut energy conversion (photovoltaics, photocatalysis, thermoelectrics), en...

Compound Copper Chalcogenide Nanocrystals

When two paramagnetic transition metal ions are present in the same molecular entity, the magnetic properties can be totally different from the sum of the magnetic properties of each ion surrounded by its nearest neighbors. These new properties depend on the nature and the magnitude of the interaction between the metal ions through the bridging ligands. If both ions have an unpaired electron (e.g. Cu2+ ions), then the molecular state of lowest energy is either a spin singlet or a spin triplet. In the former case, the interaction is said to be antiferromagnetic, in the latter case ferromagnetic. The nature and the order of magnitude of the interaction can be engineered by judiciously choosing the interacting metal ions and the bridging and terminal ligands, and, thus, by the symmetry and the delocalization of the orbitals centered on the metal ions and occupied by the unpaired electrons (magnetic orbitals). The first success in this “molecular engineering” of bimetallic compounds was in the synthesis of a Cu2+VO2+ heterobimetallic complex in which the interaction is purely ferro-magnetic. The same strategy could be utilized for designing molecular ferromagnets, one of the major challenges in the area of molecular materials. Another striking result is the possibility of tuning the magnitude of the interaction through a given bridging network by modifying the nature of the terminal ligands, which, in some way, play the role of “adjusting screws”. By careful selection of the bridging and terminal ligands, a very large antiferro-magnetic interaction can be achieved, even if the metal ions are far away from each other. Some sulfur-containing bridges are especially suitable in this respect.

Dinuclear Complexes with Predictable Magnetic Properties

Factors affecting the magnetic properties of dimeric copper(II) complexes

The determination of structural properties of dimeric transition metal ion complexes from epr spectra

Study of the relation between the structural data and magnetic interaction in oxo-bridged binuclear copper(II) compounds

: On the basis of present investigations, copper(II) compounds with subnormal magnetic moments can be roughly divided into two types. Those with direct copper-to-copper interaction have short copper-to-copper distances. In these compounds, of which copper(II) acetate monohydrate is an example, the bonding is postulated to be of the delta-bond type. In the second group, represented by acetylacetone-mono(o-hydroxyanil)copper(II), super-exchange interaction produces the lowering of the magnetic moments. It is hoped that this review will initiate structural and other investigations of these extremely interesting compounds. (Author)

Michinobu Kato

Papers

Copper(II) Complexes with Subnormal Magnetic Moments

Magnetic and spectral studies on copper(II) complexes with N-hydroxyalkylsalicylideneimines

Magnetic and spectral studies on copper(II) halide complexes with N-ethanolsalicylideneimines

Reactions of Coordinated Organic Ligands with Cupric Bromide