Relationship between metal–metal bond length and internal rotation in diruthenium tetracarboxylate paddlewheel complexes

Abstract

Relationship between metal-metal bond length and internal rotation in diruthenium tetracarboxylate paddlewheel complexes. 2 Understanding factors that influence metal-metal bond lengths is of relevance to multiply bonded species in general, and particularly important for metal-metal multiply bonded compounds as structural information is used to aid in the interpretation of physical and 25 spectroscopic properties, and to help determine the electronic structure. 0/+ species show only a small dependance on the nature of the axial ligand or R group. In common with multiply bonded compounds in general, the Ru-Ru bond length is inversely related to the formal bond order, with a small increase in Ru-Ru bond length observed upon reducing 40 Ru 2 II,III complexes (bond order = 2.5) to their Ru 2 II,II form (bond order = 2.0). 5 In this communication we present a reversal of this trend for diruthenium species containing bulky tetracarboxylates, for which a decrease in bond length is found upon reducing the Ru-Ru bond order.

Unexpected structural and electronic effects of internal rotation in diruthenium paddlewheel complexes containing bulky carboxylate ligands

“…Only the dbond overlap and strength is dependent on internal rotation, and v is greater for 6(THF) 2 as Ru 2 II;II complexes have no net d-bond to restrict the rotation. We previously proposed [33] that this internal rotation is responsible for the unusually short Ru-Ru ] with anisotropic displacement parameters drawn at the 50% level. Hydrogen atoms have been omitted for clarity, and symmetryequivalent atoms generated using the symmetry operation Àx, Ày, Àz.…”

“…One of the TiPB groups in 3(MeOH) was disordered over two positions (0.47/0.53 site occupancy), along with the methyl group of the axially coordinated MeOH molecule (0.58/0.32 site occupancy), and atoms associated with the both disordered components refined isotropically. The full experimental details and CIF files for complexes 4(THF) 2 and 6(THF) 2 have been communicated previously [33].…”

“…This effect was rationalised with the aid of theoretical calculations and the impact on the electronic structure and spectroscopic properties are also discussed. Some aspects of this work have been previously reported as a communication [33].…”

Dinuclear Rh(ii) pyrazolates as CVD precursors for rhodium thin films

“…This deviation from D 4h symmetry is seen in other dinuclear systems with sterically demanding ligands, 11 and likely allows for better packing of the large t Bu groups around the Rh 2 core. The Rh-N distances are similar to those found in complex 1.…”

A new type of paddle-wheel coordination complex

“…Deviations from this symmetry by twisting the equatorial bonds around the dimetallic axis generate helicity and thus are at the origin of chirality. 45 The distortion can be quantified by measuring the torsion angle, α, formed by the edges of the paddle that are perpendicular to the metal axis (X-M-M-Z torsion angle in Scheme 1A). In extended paddlewheel complexes, the distortion normally propagates along the axis.…”