Unprecedented Association of [Mo₆Brⁱ₇YⁱBr^a₆]³⁻ Cluster Units and [Mo^IIIBr₆]³⁻ Complexes: Synthesis, Crystal Structures, and Properties of the Double Salts Rb₃[Mo₆Brⁱ₇YⁱBr^a₆](Rb₃[MoBr₆])₃ (Y=Se, Te)

Abstract

The double salts Rb(3)[Mo(6)Br(i) (7)Y(i)Br(a) (6)](Rb(3)[MoBr(6)])(3) (Y=Se, Te) result from the partial disproportionation of the Mo(6)Br(12) octahedral-cluster-based bromide, in the presence of corresponding chalcogenides and RbBr salt (crystal data: Rb(12)[MoBr(6)](3)[Mo(6)Br(i) (7)Te(i)Br(a) (6)] (1), Pm$\bar 3$m (No. 221), a=12.1558(2) A, Z=1, R(1)=0.028; wR(2)=0.050; Rb(12)[MoBr(6)](3)[Mo(6)Br(i) (7)Se(i)Br(a) (6)] (2), Pm$\bar 3$m, a=12.144(3) A, Z=1, R(1)=0.028; wR(2)=0.050). The structures of 1 and 2 are built up from [Mo(III)Br(6)](3-) complexes and [Mo(6)Br(i) (7)Y(i)Br(a) (6)](3-) cluster units characterised by a random distribution of seven bromine and one chalcogen ligands on all the eight inner positions that face cap the Mo(6) clusters. Such a distribution implies a static orientational disorder of the [Mo(6)Br(i) (7)Y(i)Br(a) (6)](3-) units around the origin of the unit cell. Close-packed anionic layers based on [Mo(III)Br(6)](3-) complexes and [Mo(6)Br(i) (7)Y(i)Br(a) (6)](3-) cluster units are stacked in the sequence ABC. This arrangement leads to very short Br(a)--Br(a) intercluster unit distances of 3.252 A, much lower than the sum of the van der Waals radii (3.70 A). The trivalent oxidation state of molybdenum in the Mo complexes and 24 valence electrons per Mo(6) cluster have been confirmed by magnetic susceptibility measurements. Salts 1 and 2 constitute the first examples of structurally characterised bromides containing discrete [Mo(III)Br(6)](3-) complexes obtained by means of solid-state synthesis.

Supercubooctahedron (Cs6Cl)2Cs5[Ga15Ge9Se48] Exhibiting Both Cation and Anion Exchange

“…In the case of 6 , as in 4 , all the Cs atoms that form octahedra around the interstitial Cl anion were fully exchanged with Rb atoms, whereas Cs5 and Cs4 were not attacked under the experimental conditions (see the Supporting Information Table S2f). The RbBr bond length of 6 3.544(3)–3.602(3) Å is close to those in RbCu 2 Br 3 (3.545–3.705 Å)40 and Rb 12 Mo 9 Br 31 Se (3.527(1)–4.286(2) Å) 41…”

“…The RbÀBr bond length of 63 .544(3)-3.602(3) i sc lose to those in RbCu 2 Br 3 (3.545-3.705 ) [40] and Rb 12 Mo 9 Br 31 Se (3.527(1)-4.286(2) ). [41] Further details on the crystal structure investigations may be obtained from the Fachinformationszentrum Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (fax:( + 49) 7247-808-666;e -mail: crysdata@fiz-karlsruhe.de), on quoting the depository numbers CSD-428500 (1), CSD-428499 (2), CSD-428501 (3), CSD-428497 (4), CSD-428542 (5)a nd CSD-428502 (6). See also the Supporting Information.…”

The molybdenum and rhenium octahedral cluster chalcohalides in solid state chemistry: From condensed to discrete cluster units

“…11). The magnetic susceptibility measured for Rb 12 Mo 9 Br 31 Te follows a Curie law with an experimental moment consistent with molybdenum at the three oxidation state in the [MoBr 6 ] 3À complex and a 24 VEC value for the cluster unit that is non magnetic [114].…”

Self-Assembly of Ambivalent Organic/Inorganic Building Blocks Containing Re6 Metal Atom Cluster: Formation of a Luminescent Honeycomb, Hollow, Tubular Metal-Organic Framework

“…Surprisingly, in the structure of 1 , the Re 6 Q i 7 Br i (pyz) a 3 Br a 3 unit is not submitted to orientationnal disorder, and the local C 3 v of the unit symmetry is preserved. Such an ordering is not so usual in cluster chemistry since many structures based on cluster units with mixed ligandsthat differ in charge or in sizeare based on the orientational disorder of isomeric units . The result is a higher apparent symmetry than the local one.…”