[reaction: see text] The template effect exerted by tetrathiafulvalene (TTF) in the ring-closure reaction of the trication 5(3+) yielding cyclobis(paraquat-p-phenylene) has been quantitatively evaluated in acetonitrile at 62 degrees C with UV-vis spectrophotometry. The rate of ring closure of the trication 5(3+) largely increases in the presence of the template (a maximum increase of ca. 80 times at [TTF] approximately 0.14 M). The results are compared with those of other aromatic templates, 2 and 3, that were provided with polyethereal sidearms and indicate that the template ability of tetrathiafulvalene is comparable or better than that of the others.
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http://dx.doi.org/10.1021/jo050263h | DOI Listing |
Acc Chem Res
October 2020
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, United States.
Reactions catalyzed by transition metal complexes almost always entail binding of one or more reactants to the metal center, and nearly every corner of the "chiral pool" has been picked over in efforts to develop enantioselective catalysts. As reported by Alfred Werner in 1911-1912, salts of the formally -symmetric [Co(en)] trication (en = ethylenediamine) were among the first chiral inorganic compounds to be resolved into enantiomers. These air- and water-stable complexes are substitution-inert, so for 100 years they languished without application in organic synthesis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2014
Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Chiba 275-8575 (Japan).
Electronic effects on the central carbon atom of carbone, generated by the replacement of the S(IV) ligand of carbodisulfane (CDS) with other chalcogen ligands (Ph2 E, E=S or Se), were investigated. The carbones Ph2 E→C←SPh2 (NMe) [E=S(1) or Se(2)] were synthesized from the corresponding salts, and their molecular structures and electronic properties were characterized. The carbone 2 is the first carbone containing selenium as the coordinated atom.
View Article and Find Full Text PDFDalton Trans
May 2014
Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom.
The reaction of Fe(C≡CC≡N)(dppe)Cp (1) with one-half equivalent of [trans-Fe(N≡CMe)2(dppx)2][BF4]2 (dppx = dppe ([2][BF4]2) or dppm ([3][BF4]2)) affords trimetallic [trans-Fe{N≡CC≡CFe(dppe)Cp}2(dppx)2][BF4]2 (dppx = dppe [4][BF4]2; dppx = dppm [5][BF4]2). Both [4][BF4]2 and [5][BF4]2 undergo three, one-electron oxidation processes, arising from sequential oxidation of the two terminal Fe(C≡CR)(dppe)Cp moieties and finally the central Fe(N≡CR)2(dppx)2 fragment. The redox products [4](n+) and [5](n+) (n = 3, 4) have been characterised by UV-vis-NIR and IR spectroelectrochemistry.
View Article and Find Full Text PDFJ Am Chem Soc
October 2012
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany.
Reaction of tris(dimethylaminocyclopropenium) substituted phosphine 1 with K(2)PtCl(4) afforded the bench stable complex 3 which upon treatment with Ag[CB(11)H(6)Cl(6)] turned out to be an excellent catalyst for the transformation of a variety of ortho-biaryl substituted alkynes into polycyclic homo- and heteroarenes of different size, shape, and curvature through a 6-endo-dig cyclization. This constitutes the first example ever reported of using a P(1)-centered trication as ligand in catalysis. The strong π-acceptor character of 1 that derives from its three positive charges substantially increases the intrinsic π-acidity of Pt in complex 1·PtCl(2) and dramatically enhances its ability to activate π-systems toward nucleophilic attack.
View Article and Find Full Text PDFJ Chem Phys
March 2010
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QZ, United Kingdom.
Spectra of triply charged carbon disulphide have been obtained by measuring, in coincidence, all three electrons ejected in its formation by photoionization. Measurements of the CS(2)(3+) ion in coincidence with the three electrons identify the energy range where stable trications are formed. A sharp peak in this energy range is identified as the (2)Pi ground state at 53.
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