Volume 31, Issue 1

No abstract available

No abstract available

Recent results on the crystal chemistry and physical properties of intermetallic rare earth-transition metal-cadmium compounds are reviewed. The structural chemistry is compared to related magnesium and zinc compounds.

Organometallic complexes containing non-reducing monosaccharide ligands represent a small but challenging field in modern chemistry. For the main part these compounds serve as reagents and catalysts for specific applications in enantio-selective conversions, e.g., intramolecular hydroaminations, Pauson-Khand reactions and allylic alkylations, and aminations. Furthermore, transfer-hydrogenations as well as reductions can be performed by these complexes. Medicinal applications such as anticancer and anti-inflammatory active compounds, carbon monoxide-releasing molecules and radio-pharmaceutics are also among these particular applications. Therefore, the monosaccharides have been featured with various functional and thus coordinating groups and have been established in pure organometallic chemistry. Aspects in syntheses, characterizations, molecular structures and applications of these types of sugar complexes are arranged into four groups of classical organometallic ligands: cyclopentadienyl, carbonyl, hydrocarbyl and unsaturated hydrocarbyl ligands. However, this field has not yet been investigated systematically, but structural and reactivity tendencies have clearly loomed.

The chemistry of iron carbonyls covers wide fields, as shown by a survey covering the crystallographic and structural data of over 560 examples; approximately 10.5% of those examples exist as isomers and are summarized in this paper. Included are distortion (96.7%) and cis - trans (3.3%) isomerism. These are discussed in terms of coordination about iron atom, bond length and interbond angles. Distortion isomers differ only by degree of distortion in Fe-L bond distances and L-Fe-L bond angles, which are the most common. There are iron atoms in the oxidation states, zero, +2 and +3 and cis - trans isomerism (zero only). The iron atoms are two (bent), four (mostly tetrahedral), five (mostly trigonal-bipyramid) and a pseudo-octahedral coordinated with different degree of distortion.

In this paper, guanidine copper compounds are reviewed with an emphasis on structural characteristics and their application in bioinorganic chemistry and catalysis. The literature survey includes the copper coordination chemistry of biological guanidine derivatives, peralkylated guanidines including bicyclic ones and of further nitrogen-rich guanidine-type systems such as azoimidazoles, triazolopyrimidines and triaminoguanidines. From a sporadic interest dating back to the 1960s, research on this ligand class and its use in copper coordination chemistry has gained new impetus since 2000. With the synthesis of examples with sophisticated substitution at the characteristic CN 3 framework, complex problems can be addressed in several fields of chemistry. This paper analyses the different types of guanidines for their special donor properties and highlights the specific advantages of guanidines as neutral donor ligands in copper coordination chemistry where a great variety of coordination modes was found. These compounds offer the ability to distribute the formal positive charge of the metal throughout the guanidine unit and represent more than simple σ-donating ligands.