Synthesis and structural characterization of a diruthenium pentalene complex, $$[\hbox {Cp}^{*}\hbox {Ru}\{(\hbox {Cp}^{*}\hbox {Ru})_{2}\hbox {B}_{6}\hbox {H}_{14}\}(\hbox {Cp}^{*}\hbox {Ru})]$$ [ Cp ∗ Ru { ( Cp ∗ Ru ) 2 B 6 H 14 } ( Cp ∗ Ru ) ]

Abstract

Treatment of nido-[1,2-(Cp*Ru)2(μ-H)2B3H7], 1 with five equivalents of Te powder led to the isolation of diruthenium pentalene analogue [(Cp*Ru){(Cp*Ru)2B6H14}(RuCp*)], 2 and a metal indenyl complex [(Cp*Ru)2B2H6C6H3(CH3)], 3. The [(Cp*Ru)2B6H14] fragment in 2 may be considered as a true metal–boron analogue of η5-η5-pentalene ligand (C8H6) and [(Cp*Ru)B2H6C6H3(CH3)] fragment in 3 is an analogue of η5-indenyl ligand. The solid-state X-ray structures were unambiguously determined by crystallographic analysis of compounds 2 and 3. Further, the density functional theory (DFT) calculations were performed to investigate the bonding and the electronic properties of 2a (Cp analogue of 2). The frontier molecular orbital analysis of both 2a and 2b (Cp analogue of [(Cp*Ru)B8H14(RuCp*)]) reveals a lower HOMO–LUMO gap indicating less thermodynamic stability.