Low valent metal clusters — an overview

Thimmappa, B H S

doi:10.1016/0010-8545(94)07002-2

Cited by 30 publications

(12 citation statements)

References 198 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although reactions between anionic carbonyl clusters and neutral or cationic metal fragments have been extensively investigated, the nature of the resulting products is not easily predicted if high-nuclearity anions are used. This is particularly true for metal anions containing a p-block element in an exposed semi-interstitial site, because of the option the incoming ligands have of interacting with either the metals or the main-group-atom sites . As an example of this, we have recently described that the attachment of the isolobal species H + , AuPPh 3 + , and HgMo(CO) 3 Cp + to the [Fe 4 C(CO) 12 ] 2- anion occurs through different edges of the butterfly Fe 4 C skeleton, producing, as a result, three skeletal cluster isomers .…”

Section: Introductionmentioning

confidence: 99%

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

et al. 1998

View full text Add to dashboard Cite

The reaction of the carbide carbon anion [Fe5C(CO)14]2- with ClHgM in tetrahydrofuran gives the new heptametallic clusters (NEt4)[Fe5C(CO)14{μ-HgM}] (M = Mo(CO)3Cp (1a), W(CO)3Cp (1b), Mn(CO)5 (1c), Co(CO)4 (1d), Fe(CO)2Cp (1e)). The spiro species (NEt4)2[μ4-Hg{Fe5C(CO)14}2] (2) has been isolated by reaction of the pentairon carbide carbon dianion with Hg(NO3)2. The structures of 1b and 2 have been determined by X-ray diffraction methods. The anion of 1b has an Fe5 square-pyramidal metal skeleton in which a basal edge is bridged by the HgW(CO)3Cp moiety. For the cluster anion 2, the metal core consists of a four-coordinate mercury atom bridging the bond edges of two square-based-pyramidal pentairon units. The electrochemical behavior of these compounds has been investigated by cyclic voltammetry and coulometry. The 57Fe Mössbauer spectroscopy of complexes 1b,e reveals the existence of three and four types of iron sites, respectively. This study has been extended by reacting the new species (NEt4)[Fe5C(CO)14{μ-HgM}] (1a,b) with AuPPh3 + to give the neutral octametallic clusters [Fe5C(CO)14{μ-HgM}{μ-AuPPh3}] (M = Mo(CO)3Cp (3a), W(CO)3Cp (3b)).

show abstract

Section: Introductionmentioning

confidence: 99%

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

et al. 1998

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

“…In addition, coordinatively unsaturated transition metal carbonyls and organometallics, for whom transition metal carbonyls serve as model systems, are of great catalytic importance for a number of industrially important processes, e.g. isomerization, oligomerization, and hydration of olefins. , Metal carbonyls also play an important role in preparing thin metal films via chemical vapor deposition . Thus detailed studies regarding the elementary reaction mechanisms of these cluster systems are of great interest in order to gain insight into their dynamical chemical properties.…”

Section: Introductionmentioning

confidence: 99%

“…The investigation of polynuclear transition metal carbonyls in the gas phase provides an opportunity to study effects ranging from an isolated system of a single metal atom with CO molecules attached to it up to adsorbates on metal surfaces. 1 Of special interest are the binding properties exhibited by those clusters and the dynamics of bond breakage and bond formation. In addition, coordinatively unsaturated transition metal carbonyls and organometallics, for whom transition metal carbonyls serve as model systems, are of great catalytic importance for a number of industrially important processes, e.g.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ultrafast Dynamics of Transition Metal Carbonyls. 3. Intracluster Chemistry in [Cr(CO)₆]_n

Gutmann¹,

Dickebohm²,

Janello³

1999

J. Phys. Chem. A

View full text Add to dashboard Cite

We report on one-color femtosecond−pump/probe experiments applied to homogeneous chromium hexacarbonyl clusters which are prepared in a molecular beam. The pump pulse initiates bimolecular intra-cluster reactions by ultrafast photodissociation of a CO ligand from Cr(CO)6 in a 1T1u metal-to-ligand charge-transfer state. The resulting reaction products are detected mass-selectively after multiphoton ionization by the probe pulse. In contrast to nanosecond multiphoton ionization (Peifer, W. R.; Garvey, J. F. Int. J. Mass Spectrom. Ion Processes 1990 102, 1), which exclusively leads to appearance of the Cr+ mass peak, a number of novel species which may serve as interesting model systems for catalysis and surface chemistry are detected. In addition to mononuclear fragments, metal cluster ions, and coordinatively unsaturated polynuclear metal carbonyls, metal oxides and carbides are observed in the femtosecond mass spectra. The appearance of these species can be rationalized by formation of asymmetric π-bridging CO ligands in the neutral manifold. The dynamics extracted from the transients of different reaction products is interpreted using concepts of surface and inorganic cluster chemistry. Ultrafast metal−metal bond formation on a time scale much faster than our laser pulse width (ca. 150 fs) can be observed. Site exchange of CO from terminal to bridging positions on the picosecond time scale is proposed to occur in coordinatively unsaturated polynuclear metal carbonyls. Experiments at different center wavelengths (280 and 262.5 nm) reveal energy-dependent reaction channels which are closed when exciting the clusters at 280 nm. When exciting at 262.5 nm, impulsive formation of the corresponding products and decay on the picosecond time scale is observed.

show abstract

“…Traditionally, three metal nuclei is the most common minimal amount required to be considered a cluster. 3 MCCs were the subject of many studies during the 1970s and 1980s because of promising results in catalysis, the cluster cores acting as electron reservoirs, and nanoparticle development. 3,4 For a cluster to be considered an electron reservoir it must be able to undergo reversible reduction and oxidation events.…”

Section: Introduction To Metal Carbonyl Cluster Chemistrymentioning

confidence: 99%

A Foundational Study of a New Synthetic Method of Metal Carbonyl Clusters

Millard¹

View full text Add to dashboard Cite

Traditional" Metal Carbonyl Clusters (MCCs) contain a framework of multiple metal atoms bound together through formal metal-metal (M-M) bonds. Current methods of synthesis result in different cluster sizes and lack a method to control growth. This project proposes a new method of MCC synthesis to build larger structures utilizing secondary non-covalent interactions to develop "non-traditional" MCCs. The N,N'-diarylurea moiety is a strong hydrogen bond donor/acceptor that can induce self-assembly into larger secondary structures. The union of metal carbonyl and urea chemistry provides a potential method of "non-traditional" MCC synthesis. This proof of concept experiment will elucidate foundational information such as: reduction-oxidation potentials, chemical organization, chemical structure, and binding constants. The x-ray crystal structures detail a nearly planar molecular organization and refute the formation of urea ribbons due to a stabilizing intramolecular hydrogen bond interaction. Stabilizing π-π stacking and a ureaπ stacking interactions were observed as a result of the planar orientation. A titration study confirms the strong anion binding capability of the metal carbonyl appended urea moiety and confirms anion binding as a possible method of coordinating multiple units together to build "non-traditional" MCCs. The π-π interactions and urea-π interactions were observed as the largest contributor to the molecular structure and as a result, the appended group 6 metal centers are separated by distances between 6.00 Å and 8.00 Å. The close contact between metal nuclei has the potential to allow for electrochemical communication albeit not with these compounds. The characterization and synthesis of 1,3-bis(pvii isocyanophenyl)urea and its group 6 metal containing derivatives provided sufficient data to lay a solid foundation for continuing research.

show abstract

Low valent metal clusters — an overview

Cited by 30 publications

References 198 publications

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

Ultrafast Dynamics of Transition Metal Carbonyls. 3. Intracluster Chemistry in [Cr(CO)₆]_n

A Foundational Study of a New Synthetic Method of Metal Carbonyl Clusters

Contact Info

Product

Resources

About

Low valent metal clusters — an overview

Cited by 30 publications

References 198 publications

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe5C(CO)14]2-. X-ray Crystal Structures of (NEt4)[Fe5C(CO)14{μ-HgW(CO)3Cp}] and (NEt4)2[μ4-Hg{Fe5C(CO)14}2]

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe5C(CO)14]2-. X-ray Crystal Structures of (NEt4)[Fe5C(CO)14{μ-HgW(CO)3Cp}] and (NEt4)2[μ4-Hg{Fe5C(CO)14}2]

Ultrafast Dynamics of Transition Metal Carbonyls. 3. Intracluster Chemistry in [Cr(CO)6]n

A Foundational Study of a New Synthetic Method of Metal Carbonyl Clusters

Contact Info

Product

Resources

About

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

Electrophilic Additions of Mercury and Gold Species to the Anion Carbide Cluster [Fe₅C(CO)₁₄]²^-. X-ray Crystal Structures of (NEt₄)[Fe₅C(CO)₁₄{μ-HgW(CO)₃Cp}] and (NEt₄)₂[μ₄-Hg{Fe₅C(CO)₁₄}₂]

Ultrafast Dynamics of Transition Metal Carbonyls. 3. Intracluster Chemistry in [Cr(CO)₆]_n