Inverted Sandwich Rh Complex Bearing a Plumbole Ligand and Its Catalytic Activity

Abstract

A new possibility of a Rh(I) complex is demonstrated. An inverted sandwich Rh(I) complex bearing a dianionic plumbole ligand was synthesized by the reaction a dilithioplumbole with [Rh(cod)Cl] 2 . The plumbole ligand functions as a π-donor stronger than the cyclopentadienyl ligand, as evidenced by quantum-chemical calculations. The Rh(I)−plumbole complex can be applied as a catalyst for an intramolecular [2+2+2] cycloaddition reaction of a triyne.

13C and 207Pb NMR Chemical Shifts of Dirhodio- and Dilithioplumbole Complexes: A Quantum Chemical Assessment

“…Benzene-d 6 was used as the solvent in the experimental NMR measurements of the Rh 2 −plumbole and Li 2 −plumbole complexes, and a mixture of benzene-d 6 and THF was used for [Rh− plumbole] − . 16 The COSMO calculations were performed with benzene solvent with a dielectric constant ε of 2.3 using the ZORA−B3LYP method. Finally, the influence of the EE admixture on nuclear shielding was investigated using the B3LYP functional in the gas phase with 20 (standard), 30, 40, and 50% EE admixtures.…”

“…Comparing the [Rh−plumbole] − and Rh 2 −plumbole complexes, the theoretical calculations and experimental measurements show that the Pb−C α internuclear distances are longer in the later complex. 16 The bonding in the Rh 2 −plumbole complex is shown in Figure 4. We assembled the Rh 2 −plumbole complex from three fragments: two (Rh−cod) + fragments and one (plumbole) 2− fragment.…”

“…Analogous to the [Rh−plumbole] − complex, the main donation in the Rh 2 −plumbole complex originates from the π-orbital of the (plumbole The bonding analysis on the CpRh(cod) complex shows that the plumbole dianion is a stronger π-donor than the cyclopentadienyl anion. 16 The NPA charges on the Pb, C α , C β , and Rh atoms are given in Table 3. The NPA charges on the Pb and C α atoms in the Rh 2 −plumbole complex are higher (more positive) than those in [Rh−plumbole] − , supporting that π-donation from the (plumbole) 2− fragment is dominant in the Rh 2 −plumbole complex.…”

“…The Rh 2 −plumbole complex can effectively catalyze the [2 + 2 + 2] intramolecular cyclotrimerization of the alkyne 4,9-dioxadodeca-1,6,11-triyne to give a tricyclic compound. 16 NMR spectroscopy is the main technique used to characterize the molecular structures of the group 14 metalloles in solution. 11,13,15,17−19 As well as experimental measurements, quantum chemical calculations can be performed to investigate the NMR properties, such as the magnetic shielding constants and spin−spin coupling constant.…”

Triple-decker complexes incorporating three distinct deck architectures

“…1B and C). 17 For the heaviest dianionic metallole, the plumbole, 18 only anionic sandwich-type Ru and = 1,4-bis-tert-butyldimethylsilyl-2,3-bis-phenyl-plumbolyl) and [Li(thf) 4 20 and another inverted sandwich Rh complex [{(cod)Rh} 2 (m,Z 5 -L Pb )] 20 were reported. Related trimetallic triple-decker species with three distinct deck motifs have remained elusive.…”