Synthesis and Characterization of Molybdenum Carbide Clusters Mo _n C _{4 n} , ( n = 1 to 4)

Abstract

Laser radiation (XeCl laser, 308-nanometer wavelength) focused into a cell containing Mo(CO)(6) vapor produced ultrafine particles in the extended waist of the laser beam. Negative ion mass spectrometry revealed molybdenum carbide cluster ions with a stoichiometry MonC4n (n = 1 to 4). The MonC4n(-) (n = 2 to 4) ions are completely unreactive with NH(3), H(2)O, and O(2), suggesting structures in which the molybdenum atoms are unavailable for coordination to additional ligands. Collision-induced dissociation studies of these anions show the loss of MoC(4) units as the main fragmentation pathway. This observation, together with the lack of addition reactions, provides a basis for structures in which a planar cluster of two, three, or four molybdenum atoms is surrounded by, and bonded to, carbon dimers.

Theoretical study of new acceptor and donor molecules based on polycyclic aromatic hydrocarbons

“…Using B3LYP/6-311++G**, we obtained an EA of 3.62 eV, while B. Milián et al report a value of 3.42 eV calculated with B3LYP/cc-pVDZ and 3.28 eV calculated with CCSD/aug-cc-pVDZ. All these values are close to the reported experimental value of EA = 3.3 ± 0.3 [46,44].…”

“…A high electron affinity is the major characteristic of strong acceptors like TCNQ. Reported values for the EA of TCNQ vary with the applied measurement technique [43][44][45][46]. Calculated values of EA are in the range of 3.4 ± 4 eV [47].…”

Dianions of 7,7,8,8-tetracyano-p-quinodimethane and perfluorinated tetracyanoquinodimethane: Information on excited states from lifetime measurements in an electrostatic storage ring and optical absorption spectroscopy

“…15 The precursor radical anions were produced with a large yield from electrospray ionization due to the high electron affinities of the neutral mola͒ Electronic mail: sbn@phys.au.dk ecules ͑3.4± 0.2 eV of TCNQ͒. [16][17][18] The possibility of symmetric cleavage of the radical anions to produce fragment ions of similar mass-to-charge ratio as the dianions was ruled out from selection of the natural 13 C isotope at one mass higher. 9 In our previous experiments we did not obtain information about the lifetimes of the dianions with respect to electron autodetachment or about their stabilities, nor did the experiments reveal information on the electronic states being populated in the electron transfer process.…”

Relationship between Electron Affinity and Half‐Wave Reduction Potential: A Theoretical Study on Cyclic Electron‐Acceptor Compounds

“…Additional experimental information reported by Jin et al. gives further support to the theoretical EA for TCNQ, which was estimated to lie between 3.0 and 3.6 eV . These findings suggest that the experimental electron affinities reported for the cyano‐based TCNB and TCNQ compounds should be revised, especially for the latter because of its widespread use as a reference electron‐acceptor compound in the field of organic electronics …”