Assembling metals and clusters around an octaphosphine ligand based on N-substituted bis(diphenylphosphanyl)amines: structural characterization of dendrimer-like Co₁₂and Co₁₆branched clusters

Abstract

A polypodal ligand based on an aromatic ring decorated by four dppa-type diphosphine moieties has been used to prepare Pt(II) complexes and to assemble four tricobalt or tetracobalt carbonyl clusters, leading to centrosymmetric Co12 and Co16 "clusters of clusters" which were characterized by X-ray diffraction.

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

“…188 A closely related strategy developed by Braunstein and co-workers utilizes the tetra-bidentate ligand 1,2,4,5-C 6 H 2 {(CH 2 SCH 2 CH 2 N(PPh 2 ) 2 }which has been used to link four Co 4 clusters. 189 This approach lends itself to dendrimer synthesis and indeed Johnson and co-workers have applied an octa-bidentate diphosphine ligand to link together eight Fe 3 or Co 4 subunits in a dendritic array. 190,191 After deposition on a silicon substrate, atomic force microscopy has been used to image these dendrimers showing a dominant size of around 1.4 and 1.5 nm, respectively.…”

Four tetrairidiumcarbonylclusters linked by six diphosphino ligands: synthesis and X-ray structure of [{Ir4(CO)9}4(dppmb)6] (dppmb = 1,4-bis(diphenylphosphinomethyl)benzene

“…In summary, combination of Ir4 clusters and dppmb ligands produce a polycyclic assembly. While some structures have been reported with two clusters linked by diphosphino ligands 20 or four clusters held by one polypodal ligand, 15 to the best of our knowledge 1 is the first compound having more than two transition metal carbonyl cluster units as connectors and more than two diphosphines as linkers. Thus, this result is extremely interesting both for the peculiar structure obtained and, more importantly, because it clearly prompts further studies on these species, given that multifunctional two or three dimensional frameworks could be tentatively projected.…”

“…Surprisingly, the diphosphines as bridging ligands have not been explored yet, although many phosphine substituted clusters are well known 13 and CO substitution reactions have been well studied in the 70s-80s. 14 Recently, Rodriguez-Zubiri et al 15 reported on the assembly of four tricobalt or tetracobalt carbonyl clusters using a polypodal ligand based on four N-substituted bis(diphenylphosphanyl)amines.…”

Trinuclear Complexes of Zinc(II) and Cobalt(II) with a Tridentate Schiff Base Ligand Containing Phenolate and Pyridine Donor Groups

“…They can be used to hold the central metal atoms at a fixed distance providing interesting properties. In this sense, a considerable number of complexes of several polypodal ligand systems have been reported as models of different metalloproteins from several decades ago 2–7. The presence in many of these polypodal ligands of a phenolate group as a bridge to hold two central metal ions in close proximity, and also providing additional donor sites, have been required to obtain suitable biomimetic complexes 8–13…”