Details

Autor(en) / Beteiligte

• Scherer, Otto J.

Titel

Complexes with Substituent-free Acyclic and Cyclic Phosphorus, Arsenic, Antimony, and Bismuth Ligands

Ist Teil von

• Angewandte Chemie (International ed.), 1990-10, Vol.29 (10), p.1104-1122

Ort / Verlag

Zug: Hüthig & Wepf Verlag

Erscheinungsjahr

1990

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Until recently, phosphorus, arsenic, antimony and bismuth ligands were nearly always understood to be molecules such as R3E, R2E(CH2)nER2, and RC[(CH2)nER2]3(E = P, As, Sb, Bi) in which the lone pair of the atom E functions as a 2e donor. Current research interests, however, increasingly involve substituent‐free En ligands (n = 1–6), the various types of which are mainly accessible via EX3 (X = F,Cl,Br,Ph), E (SiMe3)3, (RAs)n, P4S3, As4S4, gray arsenic, and especially P4 and As4; these ligands can be stabilized in the coordination spheres of certain transition metal fragments. P1, As1 and Sb1 units with multiple M‐E bonds are found in bi‐ and trinuclear complexes; E1 units can also be encapsulated (partially or completely) in cavities of a variety of metal cluster frameworks. Metallatetrahedranes with up to three E atoms are especially common. Besides E1 units, the greatest variety of coordination modes is exhibited by E4 ligands, which are found as intact tetrahedra and also as parts of chains, polycycles, cubes and a trigonal prism. The phosphorus and arsenic species cyclo‐En, isoelectronic to the carbocyclic (CH)n species, are suitable ligands for forming sandwich complexes (n =3, 4, 5) and triple‐decker sandwich complexes (n = 3, 5, 6). In addition to the wide variety of chemical reactions, remarkable parallels are found in organic chemistry as well as in solid‐state chemistry for many of these substance classes. Some of the molecules have received lively interest from theoretical chemists. The palette of complexes with the heavier elements of the fifth main group ranges from sandwich complexes of the P‐ and As‐analogues of cyclopentadiene and benzene to metal clusters with Sb and Bi atoms. Parallels to organic chemistry and solid‐state chemistry are in evidence. The transformation shown on the right demonstrates the unusual reactivity of such compounds (Cp′ = η5‐C5Me4Et).