Synthesis and characterization of new iron-palladium and iron-platinum carbonyl anionic clusters

Longoni, Giuliano; Manassero, Mario; Sansoni, Mirella

doi:10.1021/ja00529a059

Cited by 85 publications

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“…As a result, the intermolecular N···N contact (3.390 (2) ) is slightly longer than the intermolecular distance between the ipso-carbon atoms (3.176 (2) ). Therefore, to our knowledge, + salt; [6] only the carbonyl stereochemistry is slightly different. A comparison between the most significant bond contacts is reported in Table 2.…”

Section: Synthesis and Characterization Of The [Etvmentioning

confidence: 76%

“…The M 2 - 16 ] (M= Na, K) salts have been prepared according to the literature. [6,8,14] Analysis of Fe, Pt and Au were performed by using atomic absorption on a Pye-Unicam instrument. Analyses of C, H and N were obtained with a ThermoQuest FlashEA 1112NC instrument.…”

Section: Methodsmentioning

confidence: 99%

“…The occurrence of CT and ET phenomena in solution and in the solid state was proposed on the basis of solution and solid-state spectroscopic observations. [5] We now report, the results of our investigation of the synthesis and characterization of ethylviologen salts of some carbonyl clusters, [Fe 4 Pt(CO) 16 16 ] 2À ion [6] undergoes an irreversible one-electron oxidation to [Fe 4 Pt(CO) 16 ]C À with an E8' = + + 0.01 V (against SCE and also in all following potentials). The backward response can only be observed at the highest scan rates, when reduction competes with the decomposition rate.…”

Section: Introductionmentioning

confidence: 99%

“…2À ion. [6] The EPR spectrum of this solution at 298 K shows a signal of the [EtV]C + radical ion with only a partially resolved hyperfine structure (Figure 3a). Moreover, the EPR spectrum of the glass, obtained by freezing the above solution at 100 K, only shows the isotropic signal at % 3380 G of the solvated [EtV]C + radical ion.…”

mentioning

confidence: 97%

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New Hybrid Semiconductor Materials Based on Viologen Salts of Bimetallic Fe–Pt and Fe–Au Carbonyl Clusters: First Structural Characterization of the Diradical π‐Dimer of the Diethylviologen Monocation and EPR Evidence of its Triplet State

Femoni

Iapalucci

Longoni

et al. 2007

Chemistry A European J

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The synthesis, structure, spectroscopic characterization and electrical resistivity of the [EtV](2)[Fe(4)Pt(CO)(16)], [EtV][Fe(3)Pt(3)(CO)(15)].THF, [EtV][Fe(4)Au(CO)(16)](2)2.THF (EtV=1,1'-diethyl-4,4'-bipyridilium cation) and [NEt(4)](2)[Fe(4)Au(CO)(16)] is reported. The crystal structure of [EtV](2)[Fe(4)Pt(CO)(16)] is based on infinite stacks of [(EtV)(*+)](2) pi-dimers rotated by 90 degrees and isolated [Fe(4)Pt(CO)(16)](2-) ions. Within each pi-dimer, the [EtV](*+) radical ions are perfectly eclipsed and the distance between their mean planes is 3.275 A. The EPR spectrum of the solid material at room temperature clearly indicates the presence of a significantly populated triplet state of the pi-dimer, by showing signals both at Deltam=1 and Deltam=2. The solid-state structure of [EtV][Fe(3)Pt(3)(CO)(15)].THF is based on the ionic packing of [EtV](2+) and [Fe(3)Pt(3)(CO)(15)](2-) ions, inferred from a comparison of their molecular parameters with literature data. Significant electron transfer could have been expected to give [EtV](*+)[Fe(3)Pt(3)(CO)(15)](*-) on the basis of their formal redox potentials. In spite of their different stoichiometries, the structures of [EtV][Fe(4)Au(CO)(16)](2).2 THF and [NEt(4)](2)[Fe(4)Au(CO)(16)] both contain an isomer of the monoanion [Fe(4)Au(CO)(16)](-) in solution (previously characterized in the solid state as a [NMe(3)CH(2)Ph](2)[Fe(4)Au(CO)(16)]Cl mixed salt). Resistivity measurements on pellets of powdered samples of the above compounds indicate that their tetrasubstituted ammonium salts, and complex [EtV][Fe(4)Au(CO)(16)](2)2.THF, largely behave as insulators. However, the [EtV](2)[Fe(4)Pt(CO)(16)] and [EtV][Fe(3)Pt(3)(CO)(15)].THF samples respectively display resistivities 3 and 4 orders of magnitude less than those of their corresponding ammonium salts and could be classified as semiconductor materials.

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Section: Synthesis and Characterization Of The [Etvmentioning

confidence: 76%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 97%

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New Hybrid Semiconductor Materials Based on Viologen Salts of Bimetallic Fe–Pt and Fe–Au Carbonyl Clusters: First Structural Characterization of the Diradical π‐Dimer of the Diethylviologen Monocation and EPR Evidence of its Triplet State

Femoni

Iapalucci

Longoni

et al. 2007

Chemistry A European J

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“…In support Vogler and Kunkely of this assumption there are many recent observations which suggest that intermediate hydride formation occurs during the photochemical water reduction by transition-metal complexes.22,23 The Hz-forming step (eq 5 ) introduces also the acid dependence of the photooxidation according to the Noyes model. The non-zero intercept of the plot (Figure 2) may reflect a small acid-independent contribution of the side reaction (6). Such a half-order dependence applies also to the photooxidation of Fez+" and EuZ+l2 in acidic solution with the distinction that in these cases H atoms are formed instead of H-ions.…”

Section: Resultsmentioning

confidence: 96%

Photolysis of the tantalum cluster Ta6Br122+ in aqueous acidic solution

Vogler¹,

Kunkely²

1984

Inorg. Chem.

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displacement mechanism was not discussed in detail, this mechanism seems to be similar to mechanism iv. Furthermore, Delpuech et al.30 studied two kinds of exchange reactions in [U02(nipa)2EtOH]2+ (nipa = nonamethylimidodiphosphoramide, EtOH = ethanol), i.e. the intermolecular exchange between the coordinated ethanol and free ethanol and the intramolecular exchange between the nonequivalent phosphorus atoms of the coordinated nipa. They found that the intermolecular exchange occurs more rapidly than the intramolecular exchange and the activation entropies for both reactions have negative values. These results are consistent with our results. They suggested that the inter- 23, 1360-1 363 molecular exchange proceeds through the I mechanism and the intramolecular exchange proceeds through the mechanism in which the rate-determining step is the dissociation of the coordinated ethanol or the ring opening of one of the two coordinated nipa. The former and the latter mechanisms for the intramolecular exchange correspond to mechanisms iv and ii, respectively. These facts lend support to the conclusion that mechanism iv is the most reasonable mechanism for the present exchange reactions. Acknowledgment. The authors express their thanks to Professor Gilbert Gordon of Miami University and Professor Thomas W. Swaddle of the University of Calgary for helpful discussions.Registry No. U02(acac) It is assumed that the key step involves a two-electron transfer from [Ta6Brl2I2' to a water molecule in the solvent cage, yielding [Ta&l~]~' and H-, which is scavenged by H' , generating H2.

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Synthese vielkerniger gemischtmetallischer Cluster durch Verknüpfung anionischer Ruthenium-Carbido-Cluster über Palladiumeinheiten

2000

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Vielkern-Clusterkomplexe und speziell heterometallische Cluster haben auf Grund ihrer vielseitigen Eigenschaften groûe Aufmerksamkeit erregt. [1, 2] Erwähnt sei hier beispielsweise ihre Verwendung als Vorstufe für metallische Dispersionen mit diskreter Metallatomverteilung, die als heterogene Katalysatoren ein Rolle spielen könnten. [3] Die Verknüpfung zweier kleinerer Clustereinheiten über verschiedene, verbrückende Metallatome sollte eine Möglichkeit bieten, schnell und elegant zu gröûeren Vielkern-Clustern zu gelangen. Eine Vielzahl dieser Verknüpfungen durch Umsetzung anionischer Übergangsmetallcluster mit den Kationen oder Halogeniden von Cu, [4] Ag, [5,6] Au [4e, 7] und Hg [7d, 8] ist beschrieben worden. Diese werden hierbei sandwichartig zwischen den beiden Clusterhälften eingebaut. Dagegen verläuft die Umsetzung von Clusteranionen mit Kationen oder Halogeniden der Übergangsmetalle aus der VIII. Gruppe unter Bildung riesiger Cluster, bestehend aus zwei unterschiedlichen Übergangsmetallen. Beispiele hierfür sind [Ni 38 Pt 6 (CO) 48 (H) 6Àn ] nÀ , [9] [Pd 33 Ni 9 (CO) 41 (PPh 3 ) 6 ] 4À , [10] [Ni 36 Pt 4 (CO) 45 ] 6À[11] und [Fe 6 Pd 6 (CO) 24 H] 3À . [12] In all diesen Beispielen wird Fragmentierung und anschlieûende Reorganisation der ursprünglich eingesetzten Clusterkomponente als Hauptreaktion beobachtet. Wir berichten hier über die Kupplung von Ruthenium-Carbido-Carbonyl-Clustern durch Palladiumreagentien zur Erzeugung vielkerniger Ru/Pd-Komplexe eines ¹Sandwich-Clusterª-Strukturtyps. Im Unterschied zur unvorhersehbaren Clusterbildung durch Fragmentierung und spontane Reaggregation der Edukte erhält man nach dieser Methode Strukuren ähnlich jenen, die durch den Einsatz von Metallen der Gruppen Ib und IIb als Kupplungskomponenten erhalten werden. Die Verwendung eines Übergangsmetalls der VIII. Gruppe als verbrückendes Reagens sollte die Möglichkeiten dieser Methode zur gezielten Synthese groûer, heterometallischer Cluster erweitern, vor allem unter dem Gesichtspunkt der Anwendung auf die rationale Synthese maûgeschneiderter Legierungskatalysatoren. Besonders wichtig erscheint uns dies insofern, als sowohl Ruthenium wie auch Palladium als Heterogenkatalysatoren in vielen industriellen Prozessen Anwendung finden. [13] Die Umsetzung des fünfkernigen Ruthenium-Carbido-Anions [Ru 5 C(CO) 14 ] 2À (Gegenion PPN N(PPh 3 ) 2 ) mit zwei ¾quivalenten [{Pd(C 3 H 5 )Cl} 2 ] in THF bei Raumtemperatur lieferte nach 12 h in 52 % Ausbeute dunkelrote Kristalle des ungeladenen Clusters [Pd 8 Ru 10 C 2 (CO) 27 (C 3 H 5 ) 4 ] 1. Die Röntgenstrukturanalyse (Abbildung 1) ergab, dass dieses Abbildung 1. Struktur von 1 im Kristall. Aus Gründen der Übersichtlichkeit wurden 26 CO-Liganden weggelassen. Vier Pd-Ru-Bindungen (Pd7-Ru14, Pd7-Ru24, Pd8-Ru15, Pd8-Ru25) und eine Pd-Pd-Bindung (Pd2-Pd5) haben verbrückende CO-Liganden, vier Pd-Ru-Bindungen (Pd1-Ru13, Pd3-Ru12, Pd4-Ru23, Pd6-Ru22) haben halbverbrückende CO-Liganden. Alle anderen CO-Liganden sind terminal an Rutheniumatome gebunden. Ausgewählte Bindungslängen [] und -wi...

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Synthesis and characterization of new iron-palladium and iron-platinum carbonyl anionic clusters

Cited by 85 publications

References 0 publications

New Hybrid Semiconductor Materials Based on Viologen Salts of Bimetallic Fe–Pt and Fe–Au Carbonyl Clusters: First Structural Characterization of the Diradical π‐Dimer of the Diethylviologen Monocation and EPR Evidence of its Triplet State

New Hybrid Semiconductor Materials Based on Viologen Salts of Bimetallic Fe–Pt and Fe–Au Carbonyl Clusters: First Structural Characterization of the Diradical π‐Dimer of the Diethylviologen Monocation and EPR Evidence of its Triplet State

Photolysis of the tantalum cluster Ta6Br122+ in aqueous acidic solution

Synthese vielkerniger gemischtmetallischer Cluster durch Verknüpfung anionischer Ruthenium-Carbido-Cluster über Palladiumeinheiten

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