Heterometallic Cuboidal Complexes as Derivatives of [Mo₃S₄(H₂O)₉]⁴⁺

Abstract

Heterometals can be incorporated into the MoIV3 trinuclear ion [Mo 3 S 4 (H2O) 9 ] 4+ to give cuboidal complexes of the kind Mo 3 MS 4 , or related edge-linked species {Mo 3 MS 4 } 2 or corner-shared Mo 3 S 4 MS 4 Mo 3 double cubes, depending on the heteroatom and conditions used. All the products are present as aqua ions in acidic solutions. Specific topics included in this overview are the interconversion of single and double cubes with, e.g,. M = Pd and Sn. The tendency of cubes with Μ = Τl and In to react with H + with the formation of H 2 is discussed. The formation and properties of chalcogenide-rich clusters Mo 3 X 7 4+ (X = S, Se, Te) is also considered.The relevance of Fe 4 S 4 clusters in biology ( /), and the synthesis of an extensive series of analogue complexes (2), has helped target the area of metal-sulfur clusters as one meriting increased attention. Whereas the Fe atoms in Fe 4 S 4 are tetrahedral and labile/highly reactive in aqueous solution, the octahedral Mo atoms in clusters [Mo 4 S 4 (H 2 0) 12 ] n+ η = 4,5,6, (3) are much more stable. It has also been noted that whereas the Fe 3 S 4 incomplete cube occurs in numerous proteins, it has until recently (4) proved difficult to synthesize, due to the readiness with which the linear FeU/-S) 2 FeU/-S) 2 Fe structure forms. The [Mo 3 S 4 (H 2 0) 9 ] 4+ incomplete cube on the other hand is unusually stable (years!) if stored in acidic solution, and it has been possible to explore its rich and varied solution chemistry (5).

Synthesis and structure of [M3(µ3-Se)(µ-SeS)3]4+ core compounds (M = Mo, W): a less-common type of linkage isomerism for the µ-SSe ligand

“…The reactivity patterns of the incomplete cuboidal M 3 (µ 3 -Q)-(µ-Q) 3 4ϩ clusters (M = Mo, W, Re; Q = S, Se), apart from the external ligand substitution on the metal site, are dominated by heterometal addition to the three µ-Q bridges to give a plethora of M 3 MЈQ 4 cuboidal and M 6 MЈQ 8 double cube structures. 1,2 There is also a strong tendency to form {M 3 Q 4 } 2 dimers in the solid state through short Q ؒ ؒ ؒ Q interactions. 3-5 However, little effort has been devoted to exploit this reactivity for incorporation of non-metals into the cluster.…”

Chalcogenide-bridged cuboidal clusters with M4Q4 (M = Mo, W; Q = S, Se, Te) cores

“…The different states can be accessed by cyclic voltammetry as well as controlled redox interconversions. 15,16 Also many examples of heterometallic clusters 12 are known, among them special attention has focused on the mixed-metal clusters formed by incorporation of a single metal atom into the metal depleted incomplete cube [Mo 3 S 4 (H 2 O) 9 ] 4ϩ . Solid state molybdenum compounds Mo 4 S 4 X 4 (X = Cl, Br, I) and MMo 4 Q 8 (M = Al, Ga, Q = S; M = Ga, Q = Se) are known to contain Mo 4 Q 4 cores with each Mo octahedrally coordinated by three chalcogen and three halogen atoms or six chalcogen atoms.…”

Preparation, structure and properties of three [MoxW4−xS4(H2O)12]5+ (x = 1–3) and [MoW3Se4(H2O)12]5+ cuboidal complexes alongside [Mo4S4(H2O)12]5+ and [Mo4Se4(H2O)12]5+

“…2 In aqueous solution the 5ϩ cube (11e Ϫ ) is the most readily accessed, and most extensively studied, while the 6ϩ cube (10e Ϫ ) has a tendency to fragment due to its high charge and/or low electron count. 3 In contrast ≈ 20 Group 6 to Group 15 heteroatom (MЈ) derivatives of [Mo 3 S 4 (H 2 O) 9 ] 4ϩ , having single Mo 3 MЈS 4 or related double cube core structures, give no reversible electrochemistry, 4 and with one exception (that of MЈ = Cu) 5…”