HALOGEN EXCHANGE AT RE3-CLUSTERS - A NEW SYNTHETIC ROUTE TO BINARY AND TERNARY RHENIUM(III) BROMIDES - CRYSTAL-STRUCTURES OF CS2[RE3BR11] AND CS3[RE3BR3CL9]
B. Jung et G. Meyer, HALOGEN EXCHANGE AT RE3-CLUSTERS - A NEW SYNTHETIC ROUTE TO BINARY AND TERNARY RHENIUM(III) BROMIDES - CRYSTAL-STRUCTURES OF CS2[RE3BR11] AND CS3[RE3BR3CL9], Zeitschrift fur anorganische und allgemeine Chemie, 620(6), 1994, pp. 1016-1022
Citations number
38
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Zeitschrift fur anorganische und allgemeine Chemie
The substitution of ''inner'' ligands in transition metal clusters in
aqueous HX solutions is hitherto unknown. For the first time the subst
itution of bridging and terminal chloride for bromide ions was observe
d at rhenium clusters, l(i,b))3(Cl(o,t))6(Cl(i,t))(3-x)(H2O(i,t))x](3-
x)- (x = 0 - 3), via the reaction of ''ReCl3 . 2H2O'' in hot hydrobrom
ic acid solution under an inert gas atmosphere. This establishes a new
synthetic route to ternary Re(III) bromides as well as to ReBr3. Howe
ver, ternary Re(IV) bromides, A2ReBr6 (A = Rb, Cs), are dominating in
the presence of oxygen, rhenium(III) bromides are only by-products. Da
rk brown rods of Cs2[Re3Br11] are obtained from argon saturated, hot h
ydrobromic acid solutions of ''ReCl3 . 2H2O'' and CsBr. The crystal st
ructure (orthorhombic, Pnma (Nr. 62); a = 955.51(5); b = 1 610.29(10);
c = 1372.70(9); Z = 4; V(m) = 318.0(2) cm3 mol-1; R = 0.084, R(w) = 0
.058) consists of defect clusters [Re3Br3i,bBr6o,tBr2i,tsquarei,t]2- i
n which one in plane, terminal position is not occupied. The substitut
ion of ''inner'' ligands has been observed in the case of chloride for
bromide only, the Br(i,b) and I(i,b) ligands in ReBr3 and ReI3, respe
ctively, are not substituted in hydrochloric acid even at temperatures
as high as 100-degrees-C. Bordeaux red square pyramids of CsReBrCl3 =
CS3[Re3(mu-Bri,b)3Cl6o,tCl3i,t] are obtained from hot hydrochloric ac
id solutions of ReBr3 . 2/3 H2O upon evaporation. CsReBrCl3 (orthorhom
bic, C2cm (Nr. 40); a = 1 419.0(1); b = 1 419.2(1); c = 1 080.30(8) pm
; Z = 4; V(m) = 327.6(3) cm3mol-1; R = 0.033, R(w) = 0.028) is isostru
ctural to the corresponding chloride CsReCl4.