Inorganica Chimica Acta, 83 (1984) L13-L15 Di- and Triheteronuclear Metal Cluster Anions Containing Transition Metals MELVIN L. LUETKENS Jr., FRANCESC TEIXIDOR+* and RALPH W. RUDOLPH++ Department of Chemistry, The University of Michigan, Ann Arbor, Mich. 48109, U.S.A. Received September 29,1983 Introduction None of the naked metal cluster polyanions reported so far, such as Sng4- [l] , Sb,3- [2], Sn4’ - [31, Sns ‘ - [4], SnsTl- [3], Sn,_,Ge,4- (x = O-9) [3] contain transition metal atoms. These species have been either isolated in solid state through the use of cryptate ligands in amine solvents or very recently for Sng4- as [K(HMPA)2]4Sng in en/HMPA [S] , or studied in solution, e.g.Sng_,GeX4-. How- ever, we have shown recently by the syntheses of b [(PPh,),PtSn,] and K4 [(PPh3)2PtPbg] [6] that a transition metal can be incorporated into a metal cluster polyanion if it is bonded to exocluster ligands, in close parallelism with heteroborane chemistry [7]. In this communication we wish to report the new triheteronuclear metal cluster polyanions, Nas- [L2PtTlSns] and Na, [LPdTlSns] . These react quickly to pick up another Sn atom, probably from a solid phase, liberating the formally Tl- to yield the species Na4 [LzPtSng] and Na,,[LPdSn,] , this latter species being previously unreported in the literature. Experimental Solutions of K4 [Sng] , Na4 [Sng] and Na, [TlSns] were obtained by extracting alloys of compositions KSnz, NaSnz.z5 and NaSnTll.s as previously describ- ed [3,6,8] . The complexes Pt(PPh3)4 and Pd(PPh,), were synthesized following literature procedures. Ethylenediamine(en) had been dried with Na/benzo- phenone and stored under vacuum. All syntheses were conducted in effectively the same way. The reaction H cell is schematically indi- *Author to whom correspondence should be addressed. +Permanent address: Departament de Quimica Inorghica, Universitat Aut?moma de Barcelona, (Bellaterra), Barcelona, Sp,“ ‘ “ . Deceased 11 May 1981. 0020-l 693/84/$3.00 U L13 Fig. 1. Schematic representation of the H cell. A, tiptube; B, stopcock, teflon valve; C, H cell; D, NMR tube; E, stopper. cated in Fig. 1. The synthesis of Na4 [kPdSng] was as follows: In a glove box filled with pre-purified dinitrogen, 0.3 g of NaSnz.z5 (0.26 mmols of Sng43 were placed in the left arm of the H cell and 0.3 g of Pd(PPh3)4 (0.26 mmols) in the tip tube. Thoroughly dried en (10 ml) were added to the left arm, and after assembl- ing, the H cell was taken out of the glove box. Vacuum (0.01 torr) was applied through the stopcock and the cell stored for 10 days at room temperature to allow the alloy to dissolve. The contents of the tip tube were added to the deep orange-red solution of Na4- [Sr+]. After a few hours a progressive darkening of the solution was observed. When no more color change was apparent the dark brown solution was carefully transferred to the other arm of the cell, and an appropriate fraction of it to the NMR tube which was later torch-sealed. Discussion The conversion of Na5[L$tTlSns] (I) and NaS- [LPdTlSns] (IV) into Na4[LzPtSng] (II) and Na4- [hPdSng] (V), as will be discussed later, poses serious difficulty to a solid state study of the former species. However, the nuclear magnetic properties of the participating elements provide information on the composition and behaviour of the clusters. We have used ‘ 19Sn-NMR spectroscopy to study these 0 Elsevier Sequoia/Printed in Switzerland