Antimony complexes cyclic

Porphyrin, octaethyl-, antimony hydroxide complex cyclic voltammetry, 4, 399 <73JA5140)... 

It was indeed found necessary to have excess antimony pentafluoride present in order to obtain stable alkylcarbonium hexafluoroantimonate complexes. Antimony pentafluoride is a liquid Lewis acid fluoride (b.p. 148-150°) of low dielectric constant (e 3), which has been shown by fluorine N.M.R. studies in the pure liquid state and in solution to exist in both cyclic and acyclic polymeric forms involving fluorine bridges. The antimony is in approximately octahedral co-ordination with predominant bridging by coordinating fluorines (Gillespie and Rothenbury, 1963). As fluorine generally does not show bridging properties, the structure of antimony pentafluoride itself indicates the very... 

The complex of tartaric acid and antimony (emetic) was described three centuries ago. Nevertheless, the structure of this compound has been elucidated these last fifteen years by X-ray diffraction ( 1 ). In fact, emetic presents a binuclear cyclic structure. Many authors mentioned similar complex with transition metals (vanadium (2), chromium (3)) or metalloids (arsenic (4), bismuth (5)). Emetic with phosphorus was not mentioned. Nevertheless, tartaric acid or alkyl tartrates has been utilized in phosphorus chemistry tartaric acid reacts with trialkyl phosphites giving heterocyclic phosphites (6). Starting from alkyl tartrates, we prepared spirophosphoranes with a P-H bond and sixco-ordinated compounds (7). With unprotected tartaric acid, many possibilities appear condensation as a diol, as a di(oc-hydro-xyacid), or even as a 8-hydroxyacid. 

Scherer, O. J. Complexes with substituent-free acyclic and cyclic phosphorus, arsenic, antimony and bismuth ligands, Angew. Chem., lnt. Ed. Engl. 1990, 29, 1104 Angew. Chem. 1990, 102, 1137. 

O. Scherer, Complexes with Substituent-free Acyclic and Cyclic Phosphorus, Arsenic, Antimony, and Bismuth Ligands, Angew. Chem. Int. Ed. Engl. 29, 1104-1122 (1990). 

Low-coordination organoantimony compounds are species with the coordination numbers 1 or 2 at the antimony centers, for example, stibinidenes R-Sb, distibenes R-Sb=Sb-R, stibaalkenes, R-Sb=CR2, or cyclic compounds. Stable monomeric stibinidenes or stibaalkenes are not known. Complexes with stibinidene ligands are, however, well established, and trapping of a sterically hindered stibinidene, RSb, R = 2,4,6-(MesSi)2CH]3C6H2 is achieved as a cycloadduct... 

The chemistry of boron-phosphorus compouuds has been reviewed. Numerous boron-phosphorus derivatives have been reported, but relatively few boron-arsenic or boron-antimony compounds have been described. Boron-phosphorus compounds are similar in many ways to boron nitrogen derivatives, but the teudeucy to share boudiug electrons in covalent tetrahedral compounds is much more evident with phosphorus thau with uitrogeu. lu fact, most boron phosphorus chemistry iuvolves tetrahedral borou. They are typically either phosphiue-boraue complexes, such as R3P BR j, or phosphinoboranes (R2PBR2) , cyclic or polymeric derivatives of the hypothetical H3P BH3. The chemistry of these compounds and that of boron phosphate and thiophosphate is described below. Boron phosphides are discussed in Section 2.6. 

Cyclic S-N compounds including S2N2 have been reviewed. An x-ray analysis of disulfur dinitride, S2N2, with alternating sulfur and nitrogen atoms indicates a nearly square planar array with S-N distances of 1.657 and 1.651 A and angles NSN of 89.6° and SNS of 90.4°. The structure of the bis(antimony pentachloride) complex is planar S-N, 1.619 A NSN, 84.9° SNS, 95.1°. An S2N2 complex of copper (II) chloride also is planar S-N, 1.633, 1.641 A N-S-N,... 

The redox properties of macrobicyclic iron(II) mono- and binuclear oximehydrazonates and a-dioximates formed by capping with antimony(V) and germanium(IV) triorganyles were studied by cyclic voltammetry [73, 74]. The electrochemical behaviour of these compounds is similar to that of analogous boron- and tin-capped clathrochelates. Oxidation of all mononuclear complexes involves a one-electron process, assigned to the oxidation of encapsulated iron(II) ion to iron(III) ion. This process is electrochemically... 

Antimony was also extracted as the complex with cupferron [12] or BPHA [13]. Sb(III) and As(in) can be extracted with bis(2-ethylhexyl)dithiophosphoric acid (0.1 M) in heptane from 2-4 M HCl in the presence of iodide. Only Sb(III) is re-extracted with 12 M HCl [14]. The reagent has been applied for isolation of Sb in partition chromatography [15]. Also diethyldithiophosphoric acid has been recommended for the separation of Sb(III) and As(III) [16]. In the presence of Bi and Sn, antimony was determined after extraction (CHCI3) with cyclic thiourea derivatives [17]. Sb(III) was also extracted with the use of the crown ether 18-crown-6 [18]. 

A heterocyclic complex of iron and antimony was synthesized via insertion of an Fe(CO)4 fragment into a cyclic... 

---