Infrared spectra of complexes of the thiocyanate and related ions

Publisher Summary In this chapter, one attempts to present a review giving emphasis to these new fields, and to this end as much material as possible has been subdivided under the headings of the various techniques and types of information. As a result of the chosen subdivision, certain aspects, such as the nature of the metal-to-ligand bonding are discussed in more than one section. Little mention will be made of the analytical uses of these ligands, which have recently been reviewed separately (711), of the synthesis of ring-substituted derivatives of the parent ligands, although a potentially useful method using transition-metal complexes has been reported; or of related species, such as 4,4‘-bipyridyl. The coverage of the literature is complete up to the end of 1967, and usually to the end of April 1968, and although many publications have regretfully not been mentioned, one have attempted to discuss the great majority of those papers which one believe to be of special importance.

The Chemistry of Complexes Containing 2,2′-Bipyridyl, 1, 10-Phenanthroline, or 2,2′,6′,2”-Terpyridyl as Ligands

Publisher Summary This chapter offers information on homoleptic complexes of 2,2'-bipyridine (bpy). The chapter focuses on the class of complexes that contain only bpy ligands bonded to the metal. The unique metal-binding properties of bpy were recognized from the outset. The third renaissance in bpy chemistry can be traced to the commercial availability of the ligand in the 1950s, when large amounts were required for the preparation of Diquat insecticides. The current interest in complexes of bpy is associated with the extremely interesting electrochemical, photophysical, and photoelectrochemical properties that they exhibit. 2,2'-Bipyridine is a strong field ligand that forms relatively stable complexes, with the inherent M–N bond strength enhanced by the chelate effect. Complexes with main group metal ions, and with lanthanides and actinides, can be prepared in water or organic solvents. The bis complexes are known for a range of metals and oxidation states though they tend to be more common for lower formal oxidation states. The bpy ligand is remarkable for the wide range of formal oxidation states with which it is associated. The chapter discusses the general trends in the reactivity of specific complexes under the appropriate elements. Iron, ruthenium, and osmium have played a crucial role in the development of the chemistry of 2,2'-bipyridine.

Homoleptic Complexes of 2,2′-Bipyridine

Heterothiometallic polymeric clusters

Auf der Grundlage von IR-Untersuchungen im Bereich von 200–2 400 cm−1, von Elektronenspektren und Rontgenuntersuchungen werden die Strukturen von 3d-Metall-dicyanamiden M(N(CN)2)2 (M = Mn, Fe, Co, Ni, Cu, Zn) beschrieben. Die Verbindungen lassen sich zwei verschiedenen Strukturtypen zuordnen, in denen die Anionen entweder als dreizahlige oder zweizahlige Bruckenliganden auftreten. Kobalt- und Mangan-dicyanamid bilden Struktur-Isomere mit pseudo-oktaedrischer (α-Formen) bzw. -tetraedrischer Mikrosymmetrie (β-Formen). Der polymertetraedrische Verbindungstyp, dem auch Zinkdicyanamid zuzuordnen ist, scheint eine bisher nicht beschriebene Bindungsart verbruckender Dicyanamid-Gruppen zu enthalten.



Metal Pseudohalides. 27. Structures of Dicyanamides of Bivalent 3d Metals M(N(CN)2)2



On the basis of infrared investigations in the region of 200–2 400 cm−1, of electronic spectra and X-ray studies the structures of the dicyanamides of bivalent 3d metals M(N(CN)2)2 (M = Mn, Fe, Co, Ni, Cu, Zn) are described. The compounds may be attributed to two different structure types with the anions acting as tri- or bi-dentate bridging ligands, cobalt and manganese dicyanamide are forming structural isomers with pseudooctahedral (α-forms) or pseudotetrahedral (β-forms) microsymmetry. The polymer-tetrahedral type of the compounds, which is also including Zn(N(CN)2)2 seems to contain a hitherto undescribed bonding mode of bridging dicyanamide groups.

C.S. Williams

Papers

Infra-red spectra (3000-200 cm−1) of metal-isothiocyanate complexes

The far infra-red spectra of 2,2′-dipyridyl and 1,10-phenan-throline complexes of alkyl tin halides

Low frequency infra-red spectra of 2:2'-bipyridyl complexes of bivalent and trivalent transition metals