"Bottled" spiro-doubly aromatic trinuclear [Pd2Ru]+ complexes.

Maksim Kulichenko,Davide Balestri,Anna Monfredini,Alexander I Boldyrev,Alvaro Muñoz-Castro,Giovanni Maestri,Nikita Fedik

doi:10.1039/d0sc04469e

Maksim Kulichenko, Davide Balestri + Show 5 more

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https://doi.org/10.1039/d0sc04469e

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Abstract

Following an ongoing interest in the study of transition metal complexes with exotic bonding networks, we report herein the synthesis of a family of heterobimetallic triangular clusters involving Ru and Pd atoms. These are the first examples of trinuclear complexes combining these nuclei. Structural and bonding analyses revealed both analogies and unexpected differences for these [Pd2Ru]+ complexes compared to their parent [Pd3]+ peers. Noticeably, participation of the Ru atom in the π-aromaticity of the coordinated benzene ring makes the synthesized compound the second reported example of ‘bottled’ double aromaticity. This can also be referred to as spiroaromaticity due to the participation of Ru in two aromatic systems at a time. Moreover, the [Pd2Ru]+ kernel exhibits unprecedented orbital overlap of Ru dz2 AO and two Pd dxy or dx2−y2 AOs. The present findings reveal the possibility of synthesizing stable clusters with delocalized metal–metal bonding from the combination of non-adjacent elements of the periodic table which has not been reported previously.

Highlights

For more than a hundred years of its existence, aromaticity has proven itself to be an extremely useful and reliable concept[1,2,3,4,5,6] which enables the explanation of bonding patterns in many non-trivial chemical systems
Following an ongoing interest in the study of transition metal complexes with exotic bonding networks, we report the synthesis of a family of heterobimetallic triangular clusters involving Ru and Pd atoms
The present findings reveal the possibility of synthesizing stable clusters with delocalized metal–metal bonding from the combination of non-adjacent elements of the periodic table which has not been reported previously

Summary

Introduction

For more than a hundred years of its existence, aromaticity has proven itself to be an extremely useful and reliable concept[1,2,3,4,5,6] which enables the explanation of bonding patterns in many non-trivial chemical systems. In 2018 Saito et al made a game changing discovery which put an end to all doubts regarding aromaticity and its transferability throughout different branches of materials chemistry. They managed to synthesize a doubly aromatic compound [C6(SePh)6]2+ that possesses cyclic s-symmetric and p-symmetric aromatic rings.[5] This milestone indicates that other types of aromaticity apart from the conventional p-type are not elusive. All-metal aromaticity[12,13,14,15,16,17,18,19] is a wellknown concept that enables describing the bonding properties of all-metal compounds similar to those involving maingroup elements.[20,21]

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