191272-31-8Relevant academic research and scientific papers
Divalent tin and lead compounds EX2 acting as bridging ligands in [{(CO)5M}2EX2]2- (E = Sn, Pb; M = Cr, Mo, W): Preparation and properties
Kircher, Peter,Huttner, Gottfried,Schiemenz, Berthold,Heinze, Katja,Zsolnai, Laszlo,Walter, Olaf,Jacobi, Albrecht,Driess, Alexander
, p. 687 - 699 (1997)
The reaction of Na2[M2(CO)10] (M = Cr, Mo, W) with SnHal2 (Hal = CI, Br) is a well established procedure for the synthesis of anions of type A, [{(CO)sMJSnHal3]~. Conditions are described which, for the same type of procedure, result in the additional formation of dianions of type B, [((CO)5M)2SnHal2]2-. Procedures for separating these two types of anions in the form of their stable [Ph4P]+ or [nBu4NJ+ salts by appropriate salt metathesis are presented. The structures of these species have been characterized by X-ray analysis of three salts containing type A anions and two salts containing type B anions. The reactivity of the type B salts containing the bulky cations [Ph4P]+ or [nBu4N]+, respectively, is remarkably low; the salts are, however, transformed into highly reactive sodium salts by further metathesis with Na[BPh4]. In such salts the halide substituents are easily exchanged as shown by the synthesis of [((CO)5Cr}2Sn(oxinato)]- (4)-, from [Na-(THF)x]2[{(CO)5CrJ}SnCl2] and sodium 8-oxoquinolate, Na[C9H6NOJ. The structure of the anion, 4, is compared to the structure of [|(CO)5Cr]Sn(oxinato)2] (5), which is obtained from [((CO)5Cr)SnCl2 ·THF] and sodium 8-oxochinolate. The preparation of the dinuclear anions [((CO)5CrJ2E(OOCCH3)2]2- (E = Sn, 2g; E = Pb, 3) is accomplished by the reaction of [Ph4P]2[Cr2(CO)10] with the corresponding acetates E(OOCCH3)2. While 2g and 3 are formal analogues of the type-B anions, their structures reveal an asymmetrical η2-coordination of the two acetato ligands, in each case ending up in a 4 + 2 coordination for the main group centres, instead of the four-coordination observed for [{(CO)5M)2SnHal2]2-. All compounds have been characterized by usual spectroscopic and analytical techniques. X-ray analyses have been performed for selected examples. 119Sn-NMR data are presented for all of the compounds which contain tin-centred ligands. VCH Verlagsgesellschaft mbH,.
