Controlled Synthesis of Early-Late Zr-Ir-Rh Heterotrimetallic Compounds by Metal Exchange Reactions

Abstract

Sulfido ligands meet the coordination and electronic requirements for stabilizing compounds containing divergent metal centers in close proximity, as shown by the controlled syntheses of early-late bimetallic (ZrIr(2) and ZrIr) and trimetallic complexes (ZrIrRh). The slow rotation of one 1,3-di-tert-butylcyclopentadienyl (Cp(tt)) ring in 1 (structure shown) allows the observation of two rotamers at room temperature. cod=1,5-cyclooctadiene. [Cp(tt)(2)Zr(µ(3)-S)(2){Ir(CO)(2)}{Rh(cod)}] 1

Synthesis, Reactivity, and Catalytic Activity of Triangular ZrM2(M = Rh, Ir) Early−Late Heterobimetallic Complexes

“…As proposed from spectroscopic data, complexes 6 and 9 are trinuclear with a triangular (9) and 2.290(13) Å), 16 and longer than the reported distances in mononuclear zirconium thiolate complexes containing unsubstituted Cp rings (range 2.203(3)-2.220(1) Å). 19 The angles centered on the Zr with the centroids of the Cp tt ligands (G(1)-Zr-G(2), 127.62(7)° in 6 and 126.75(10)° in 9) are significantly larger than the typical value for a tetrahedral geometry, most probably due to the presence of the bulky tert-butyl substituents.…”

“…19 The angles centered on the Zr with the centroids of the Cp tt ligands (G(1)-Zr-G(2), 127.62(7)° in 6 and 126.75(10)° in 9) are significantly larger than the typical value for a tetrahedral geometry, most probably due to the presence of the bulky tert-butyl substituents. The relative dispositions of the Cp tt substituents in both complexes are eclipsed and in the side of the trinuclear core, favoring a smaller G(1)-Zr-G(2) angle than that described in the related Zr-Ir-Rh complex, 16 129.8(4)°, where the Cp tt rings exhibit a staggered disposition. In fact, the angles G(1)-Zr-G(2) in 6 and 9 are at the lower end of mononuclear zirconium thiolate complexes of the type Cp 2 Zr(SR) 2 (range 127.7(3)-130.4(1)°).…”

“…However, these bond distances in both complexes are comparable to those reported in the Zr-Ir-Rh analogue (2.506(3) and 2.519(3) Å). 16 The angles S-Zr-G (mean value 109.95(4) in 6 and 109.73(4)°in 9) are quite close to the ideal value for a tetrahedral geometry. The dihedral angles formed by the LSQ-planes defined by the carbon atoms in the two Cp tt rings are almost identical, 61.63 (16) in 6 and 62.1(2)° in 9.…”

“…Again it is noticeable the unusual chemical shifts of one of the Cp tt rings of the staggered isomer, as previously observed. 16 The number of signals from the tert-butyl groups and the auxiliary nbd and tfbb ligands in the 13 C{ 1 H} and 1 H NMR spectra corroborate the identification and symmetry of both rotamers. For example, the eclipsed rotamers (1a, 2a) display two doublets for the olefinic carbons in the 13 C{ 1 H} NMR spectra while the staggered rotamer 2b shows four signals for the olefinic carbons, in agreement with the lower symmetry.…”

Tetrametallic clusters (Ir2Rh2) through an ancillary ortho-carborane-1,2-dichalcogenolato ligands

“…The metal atoms of the core adopt a quite irregular nearly planar Ir 2 Rh 2 arrangement (Ir(1), Ir (2), Rh(1) and Rh(2) metals are coplanar with maximum deviation at 0.177 Å ). To our knowledge, this type of Ir 2 Rh 2 core cluster is rare, only some pyramidal shape metal carbonyl clusters of Ir 2 Rh 2 (CO) 12 and its derivatives were reported previously. 11 The two dithiolato ligands of carboranes are situated at the both sides of the tetrametallic plane with three of the sulfur atoms acting as l 2 -bridging ligands and the other sulfide simultaneously connecting three metals.…”