Structural variations, electrochemical properties and computational studies on monomeric and dimeric Fe-Cu carbide clusters, forming copper-based staple arrays
Articolo
Data di Pubblicazione:
2011
Citazione:
Structural variations, electrochemical properties and computational studies on monomeric and dimeric Fe-Cu carbide clusters, forming copper-based staple arrays / R. Della Pergola, M. Bruschi, A. Sironi, M. Manassero, C.P.M. Manassero, D. Strumolo, S. Fedi, P. Zanello. - In: DALTON TRANSACTIONS. - ISSN 1477-9226. - 40:20(2011), pp. 5464-5475. [10.1039/c0dt01766c]
Abstract:
The halide ligands of [Fe4C(CO)12(CuCl)2]2- (1) and [Fe5C(CO)14CuCl]2- (2) can be displaced by N-, P- or S-donors. Beside substitution, the clusters easily undergo structural rearrangements, with loss/gain of metal atoms, and formation of Fe4Cu/Fe4Cu3 metallic frameworks. Thus, the reaction of 1 with excess dppe yielded [{Fe4C(CO)12Cu}2(-dppe)]2- (3). [{Fe4C(CO)12Cu}2(-pyz)]2- (4) was obtained by reaction of 2 with Ag+ and pyrazine. [Fe4C(CO)12Cu-py]- (5) was formed more directly from [Fe4C(CO)12]2-, [Cu(NCMe)4]+ and pyridine. [Fe4Cu3C(CO)12(-S2CNEt2)2]- (6) and [{Fe4Cu3C(CO)12(-pz)2}2]2- (7) were prepared by substitution of the halides of 1 with diethyldithiocarbammate and pyrazolate, in the presence of Cu(I) ions. All these products were characterized by X-ray analysis. 3 and 4 and 5 are square based pyramids, with iron in the apical sites, the bridging ligands connect the two copper atoms in 3 and 4. 6 and 7 are octahedral clusters with an additional copper ion held in place by the two bridging anionic ligands, forming a Cu3 triangle with Cu-Cu distances ranging 2.63-3.13 Å. In 7, an additional unbridged cuprophilic interaction (2.75 Å) is formed between two such cluster units. DFT calculations were able to reproduce the structural deformations of 3-5, and related their differences to the backdonation from the ligand to Cu. Additionally, DFT found that, in solution, the tight ion pair [NEt4]27 is almost isoenergetic with the monomeric form. Thus, 3, 4 and 7 are entities of nanometric size assembled either through conventional metal-ligand bonds, or weaker electrostatic interactions. None of them allows electronic comunication between the two monomeric units, as shown by electrochemistry and spectroelectrochemical studies.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
approximate coulomb potentials; auxiliary basis-sets; X-ray structures; carbonyl clusters; molecular-structure; gold nanoparticle; complexes; crystal; reactivity; chemistry
Elenco autori:
R. Della Pergola, M. Bruschi, A. Sironi, M. Manassero, C.P.M. Manassero, D. Strumolo, S. Fedi, P. Zanello
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