Abstract:The redox chemistry of [WM(f~lvalene)(CO)~], M = Fe (1) and Ru (2) allows the specific redox properties of each metal centre to be distinguished.
“…40b,45 Redox recognition upon reduction is observed, however, in the CV of [FeWFv(CO) 5 ] (Fv ) fulvalenyl, see Scheme 10), specifically generating the radical anion [Fe • W -Fv(CO) 5 ]. 46 This specificity is due to the regulation of the electronic communication between the two metals via the fulvalenyl bridge. Dimerization via the iron center leads to the tetrametallic complex whose synthesis can be achieved using stoichiometric amounts of the electronreservoir reagent [Fe I Cp(C 6 Me 6 )] (Scheme 10).…”
Section: Electronic Communication and Redox Recognitionmentioning
confidence: 99%
“…The CVs of most homo- and heterobimetallic fulvalene carbonyl complexes show a single irreversible two-electron wave. 40b, Redox recognition upon reduction is observed, however, in the CV of [FeWFv(CO) 5 ] (Fv = fulvalenyl, see Scheme ), specifically generating the radical anion [Fe • W - Fv(CO) 5 ] …”
Section: Electronic Communication and Redox
Recognitionmentioning
The molecular sciences of the transition metals have potential applications in a new fascinating field: molecular electronics. 1,2 This hope is based "inter alia" on the fact that the oxidation states of transition metals can be varied to a great extent and thus that many electrontransfer processes can result. 2 By suitable molecular engineering, it should become possible to assemble and tune molecular devices including transition metals and organize their interface with the macroscopic world. The interplay between light, electron transfer, and magnetooptic properties will then provide efficient and precise molecular sensors for the various needs of future technology. [1][2][3][4][5] In this context, we wish to examine the electronic properties of simple bimetallic model systems and the electronic communication between the two metals across a delocalized bridging ligand in these molecules. This is the subject of the present Account, which will address the following questions: (i) Can one design simple ligandbridged bimetallic complexes as good models for molecular conductors? (ii) What factors control the electronic communication between the two metals across a delocalized ligand? (iii) What are the consequences and applications of single-and multiple-electron transfers in such systems? (iv) Can the molecular electronics of hydrocarbon-bridged bimetallic complexes be, in turn, useful for their organometallic chemistry (i.e., synthesis, catalysis, and mechanistic studies)?Electron-transfer processes between two redox centers have been examined with various linkers: simple inorganic atoms or ligands such as, for instance, pyrazine, 4,4′bipyridine, 6 polyenes including -carotene, 7 polyphenyls, 8 polyynes, 9 and polyaromatics. 10 Long-range electron-transfer studies have been especially useful for biological systems 11 including DNA; 11f photoinduced electron-transfer studies have played a key role in providing high driving forces to test Marcus theory. 12,13 The pioneering work in the area of electronic communication between two metals has been reported by Taube with a series of diruthenium complexes following the famous pyrazine-bridged Creutz-Taube ion which allowed the distinction between trapped (class II) and detrapped (class III) mixed-valence compounds. 6 The second example, biferrocene, 14 is already a relatively good example for us to start with, having a single fulvalenyl bridge. Indeed, we will concentrate on * FAX. † Abbreviations: Cp, η 5 -C5H5; Cp*, η 5 -C5Me5; Fv, µ2,η, 5 η 5 -fulvalenyl unless noted otherwise.(1) (a) Balzani, V.; Scandola, F. Supramolecular Chemistry; Ellis Hordwood: New York, 1991. (b) Balzani, V.; Moggi, L.; Scandola, F. In Supramolecular Photochemistry; Balzani, V., Ed.; Reidel: Dordrecht, FIGURE 3. CV of (a) parent series, 5a 2+ (s) and 3a 2+ (---), and (b) permethylated series 5b 2+ (s) and 3b 2+ (---) (3.3 × 10 -5 M DMF solution; 0.1 M [n-Bu 4 N] + [BF 4 ] -; Hg cathode; scan rate 0.4 V‚s -1 ; -35°C). Rearrangement energy [parent series (a)] and ∆E 2 -∆E 1 [permethylated seri...
“…40b,45 Redox recognition upon reduction is observed, however, in the CV of [FeWFv(CO) 5 ] (Fv ) fulvalenyl, see Scheme 10), specifically generating the radical anion [Fe • W -Fv(CO) 5 ]. 46 This specificity is due to the regulation of the electronic communication between the two metals via the fulvalenyl bridge. Dimerization via the iron center leads to the tetrametallic complex whose synthesis can be achieved using stoichiometric amounts of the electronreservoir reagent [Fe I Cp(C 6 Me 6 )] (Scheme 10).…”
Section: Electronic Communication and Redox Recognitionmentioning
confidence: 99%
“…The CVs of most homo- and heterobimetallic fulvalene carbonyl complexes show a single irreversible two-electron wave. 40b, Redox recognition upon reduction is observed, however, in the CV of [FeWFv(CO) 5 ] (Fv = fulvalenyl, see Scheme ), specifically generating the radical anion [Fe • W - Fv(CO) 5 ] …”
Section: Electronic Communication and Redox
Recognitionmentioning
The molecular sciences of the transition metals have potential applications in a new fascinating field: molecular electronics. 1,2 This hope is based "inter alia" on the fact that the oxidation states of transition metals can be varied to a great extent and thus that many electrontransfer processes can result. 2 By suitable molecular engineering, it should become possible to assemble and tune molecular devices including transition metals and organize their interface with the macroscopic world. The interplay between light, electron transfer, and magnetooptic properties will then provide efficient and precise molecular sensors for the various needs of future technology. [1][2][3][4][5] In this context, we wish to examine the electronic properties of simple bimetallic model systems and the electronic communication between the two metals across a delocalized bridging ligand in these molecules. This is the subject of the present Account, which will address the following questions: (i) Can one design simple ligandbridged bimetallic complexes as good models for molecular conductors? (ii) What factors control the electronic communication between the two metals across a delocalized ligand? (iii) What are the consequences and applications of single-and multiple-electron transfers in such systems? (iv) Can the molecular electronics of hydrocarbon-bridged bimetallic complexes be, in turn, useful for their organometallic chemistry (i.e., synthesis, catalysis, and mechanistic studies)?Electron-transfer processes between two redox centers have been examined with various linkers: simple inorganic atoms or ligands such as, for instance, pyrazine, 4,4′bipyridine, 6 polyenes including -carotene, 7 polyphenyls, 8 polyynes, 9 and polyaromatics. 10 Long-range electron-transfer studies have been especially useful for biological systems 11 including DNA; 11f photoinduced electron-transfer studies have played a key role in providing high driving forces to test Marcus theory. 12,13 The pioneering work in the area of electronic communication between two metals has been reported by Taube with a series of diruthenium complexes following the famous pyrazine-bridged Creutz-Taube ion which allowed the distinction between trapped (class II) and detrapped (class III) mixed-valence compounds. 6 The second example, biferrocene, 14 is already a relatively good example for us to start with, having a single fulvalenyl bridge. Indeed, we will concentrate on * FAX. † Abbreviations: Cp, η 5 -C5H5; Cp*, η 5 -C5Me5; Fv, µ2,η, 5 η 5 -fulvalenyl unless noted otherwise.(1) (a) Balzani, V.; Scandola, F. Supramolecular Chemistry; Ellis Hordwood: New York, 1991. (b) Balzani, V.; Moggi, L.; Scandola, F. In Supramolecular Photochemistry; Balzani, V., Ed.; Reidel: Dordrecht, FIGURE 3. CV of (a) parent series, 5a 2+ (s) and 3a 2+ (---), and (b) permethylated series 5b 2+ (s) and 3b 2+ (---) (3.3 × 10 -5 M DMF solution; 0.1 M [n-Bu 4 N] + [BF 4 ] -; Hg cathode; scan rate 0.4 V‚s -1 ; -35°C). Rearrangement energy [parent series (a)] and ∆E 2 -∆E 1 [permethylated seri...
“…The chemistry of dinuclear organometallic complexes containing the fulvalene (Fv) ligand has recently become a topic of renewed interest. − Besides their interesting electrochemical , and magnetic properties, the reactivities of Fv complexes should differ from those of their Cp analogues. There are at least two important reasons that suggest this difference.…”
The reaction of a dicarbomethoxydihydrofulvalene
solution with Mo(CO)6 leads to the
formation of two isomers of
(η5:η5-(C5H3CO2Me)2)Mo2(CO)6
(1 and 2). The X-ray structure
of both compounds has been determined. Reaction of 2
with LiEt3BH yields
Li2[(η5:η5-(C5H3CO2Me)2)Mo2(CO)6]
(3), and this with Hg(CN)2 results in the
insertion of Hg into the Mo−Mo bond giving
(η5:η5-(C5H3CO2Me)2)Mo2(CO)6Hg
(4). The electrochemical study of
1−4 is
reported. The two-electron reduction of 1 and
2, through an ECE mechanism, leads to the
dianions. This reduction takes place at a significantly less
negative potential than for the
unsubstituted fulvalene
(η5:η5-C10H8)Mo2(CO)6
(5) due to the electron-withdrawing properties
of the carbomethoxy substituents. The oxidation of 1
and 2 is also affected by the
substituents, taking place at a more positive potential than
5. The reduction of 4 yields
the
dianion 2
2- and liberates Hg.
“…In addition, the C(5)−C(6) distance of 1.38(2) Å is significantly shorter than the average C−C distance in the C(1)−C(5) ring [average 1.46(2) Å] and the C(6)−C(10) ring [average 1.44(2) Å]. Consequently, the structural parameters are more consistent with the η 4 :η 4 -Rh(I)−Rh(I) form 8 , rather than an η 5 :η 5 -Rh(II)−Rh(II) structure 10 ; the latter structural type is far more common in other dinuclear fulvalene complexes of rhodium − and other metals. − …”
Reaction of perfluoroisopropyl iodide with
Rh(C5H5)(PMe3)2 generates a perfluorocarbanion intermediate along with [Rh(C5H5)(PMe3)2I]+, which react to
give fluoroalkylation of the cyclopentadienyl ring. When
the intermediate fluorocarbanion is trapped by CH3OD
to give (CF3)2CFD, the resultant methoxide anion reacts
with [Rh(C5H5)(PMe3)2I]+ to give a dinuclear fulvalene
complex that has been characterized crystallographically.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
