Cluster chemistry in the Noughties: new developments and their relationship to nanoparticles

Abstract

Over the past decade, the chemistry of low-valent transition metal clusters has again come to the fore, primarily as a result of the development of nanochemistry and the realization that large clusters are on the cusp of the nano-domain. This perspective focuses on these recent developments in low-valent transition metal cluster chemistry, specifically looking at cluster-nanoparticles, the use of small and medium sized clusters as nanoparticle precursors, the development of clusters as homogeneous catalysts and hydrogen uptake and storage systems, together with fundamental discoveries relating to novel transformations that can take place within the cluster framework.

Synthesis of new heterometallic complexes by tin–sulfur bond cleavage of pySSnPh3 (pySH = pyridine-2-thiol) at triruthenium and triosmium centres

“…If tin-containing transition metal clusters are to be used towards the synthesis of catalyticallyactive nanoparticles then facile and high-yielding routes to these clusters is a necessity [32].…”

Centrosymmetric [Mn2(CO)6(μ-thpymS)2] (thpymS = tetrahydropyrimidine-2-thionato) as a synthon to mixed-metal clusters

“…The coordination geometry around each manganese center is a distorted octehedron with the carbonyl ligands arranged in a facial fashion. The distortion from octahedral coordination geometry is evident from the reduction of the NeMneS chelate angles to 68.60 (5) . The salient feature of the molecule is that it adopts a centrosymmetric structure whereas all related complexes of the general formula [M 2 (CO) 6 (m-L) 2 ] (M ¼ Mn, Re; L ¼ 2-mercapto-1-methylimidazolato, pyridine-2-thiolato, 6-methylpyridine-2-thiolato, 2-thiazoline-2-thiolato) adopt a chiral structure with C 2 symmetry [9,19e21].…”

“…As such this is an area of research which has been sustained over a long period but the lack of systematic and efficient synthetic routes to the desired heterometallic complexes often limits their study and to date only few isostructural series are known [4]. Consequently, the rational and high yielding synthesis of mixedmetal clusters is a significant challenge to the synthetic chemists if such species are to be properly investigated in order to fully exploit their unique chemical and physical properties [5].…”

“…The molecule contains a single manganese atom with four terminal carbonyl groups and a chelating k 1 :h 1 -SCNHC 3 H 6 NCO ligand. The coordination geometry around manganese is a distorted octahedron which is evident from the short chelate angle, C(5)e Mn(1)eS(1) 84.07(5) . The most intriguing feature of 2 is that it contains an unusual k 1 :h 1 -SCNHC 3 H 6 NCO ligand which is most probably formed by the carbonenitrogen coupling between a nitrogen atom of the thpymSH ligand and a carbonyl carbon bonded to manganese.…”

Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

“…The amount of clusters that can be loaded onto a nanocarbon structure will be evaluated, as well as their behavior during the first steps of thermal treatment, which aims to gently remove the ligands and coalesce the metal cores to form ultrasmall heterometal nanoparticles supported on nanocarbons. It is generally believed that the clusters first lose their ligands, accompanied by an increased interaction with the surface, and then agglomerate with prolonged heat treatment [39–41]. This study is dedicated to the first stage of activation, i.e., denuded cluster cores before agglomeration, and in particular, their characterization at atomic resolution to prove their bimetal nature within individual nanoparticles.…”