7 research outputs found
Structural Conformers of (1,3-Dithiol-2-ylidene)ethanethioamides: The Balance Between Thioamide Rotation and Preservation of Classical Sulfur-Sulfur Hypervalent Bonds
The reaction of N-(2-phthalimidoethyl)-N-alkylisopropylamines and S2Cl2 gave 4-N-(2-phthalimidoethyl)-N-alkylamino-5-chloro-1,2-dithiol-3-thiones that quantitatively cycloadded to dimethyl or diethyl acetylenedicarboxylate to give stable thioacid chlorides, which in turn reacted with one equivalent of aniline or a thiole to give thioanilides or a dithioester. Several compounds of this series showed atropisomers that were studied by a combination of dynamic NMR, simulation of the signals, conformational analysis by DFT methods, and single crystal X-ray diffraction, showing a good correlation between the theoretical calculations, the experimental values of energies, and the preferred conformations in the solid state. The steric hindering of the crowded substitution at the central amine group was found to be the reason for the presence of permanent atropisomers in this series of compounds and the cause of a unique disposition of the thioxo group at close-to-right angles with respect to the plane defined by the 1,3-dithiole ring in the dithiafulvene derivatives, thus breaking the sulfurâsulfur hypervalent bond that is always found in this kind of compounds.Ministerio
de EconomıaÌ y Competitividad, Spain (Project CTQ2012-
31611), Junta de Castilla y LeoÌn, ConsejeriÌa
de EducacioÌn y
Cultura y Fondo Social Europeo (Project BU246A12-1), and
the European Commission, Seventh Framework Programme
(Project SNIFFER FP7-SEC-2012-312411
The African Youth Civic Movements and the Struggle for Peace: The Case of Balai Citoyen and Filimbi
Nickel ethylene tetrathiolate polymers as nanoparticles: a new synthesis for future applications?
Electrochemistry, Chemical Reactivity, and Time-Resolved Infrared Spectroscopy of Donor-Acceptor Systems [(Q(x))Pt(pap(y))) (Q = Substituted o-Quinone or o-Iminoquinone; pap = Phenylazopyridine)
The donorâacceptor complex [(O,NQ2â)Pt-
(pap0)] (1; pap = phenylazopyridine, O,NQ0 = 4,6-di-tertbutyl-
N-phenyl-o-iminobenzoquinone), which displays strong
Ï-bonding interactions and shows strong absorption in the
near-IR region, has been investigated with respect to its redoxinduced
reactivity and electrochemical and excited-state
properties. The one-electron-oxidized product [(O,NQâąâ)Pt-
(pap0)](BF4) ([1]BF4) was chemically isolated. Single-crystal
X-ray diffraction studies establish the iminosemiquinone form
of O,NQ in [1]+. Simulation of the cyclic voltammograms of 1
recorded in the presence of PPh3 elucidates the mechanism
and delivers relevant thermodynamic and kinetic parameters
for the redox-induced reaction with PPh3. The thermodynamically
stable product of this reaction, complex [(O,NQâąâ)
Pt(PPh3)2](PF6) ([2]PF6), was isolated and characterized by X-ray crystallography, electrochemistry, and electron paramagnetic
resonance spectroscopy. Picosecond time-resolved infrared spectroscopic studies on complex 1b (one of the positional isomers
of 1) and its analogue [(O,OQ2â)Pt(pap0)] (3; O,OQ = 3,5-di-tert-butyl-o-benzoquinone) provided insight into the excited-state
dynamics and revealed that the nature of the lowest excited state in the amidophenolate complex 1b is primarily diimine-ligandbased,
while it is predominantly an interligand charge-transfer state in the case of 3. Density functional theory calculations on
[1]n+ provided further insight into the nature of the frontier orbitals of various redox forms and vibrational mode assignments.
We discuss the mechanistic details of the newly established redox-induced reactivity of 1 with electron donors and propose a
mechanism for this process