o-Semiquinonato and o-iminosemiquinonato rhodium complexes. EPR study of the reactions in coordination sphere of rhodium

Spin-labelled cyclometallated palladium complexes. EPR study of dynamic processes in coordination sphere

“…Enthalpy stabilizes products of coordination having larger number of the bonds, whereas products of dissociation are entropy favorable due to enlarging of number of particles. Notably, DH 0 2 and DS 0 2 values are close to those ones for similar reversible PPh 3 coordination to carbonyl-phosphano complexes of rhodium [13] (DH 0 = À22 to À27 kJ/mole,…”

“…So, 1cÁ(PPh 3 ) 2 should have octahedral geometry with apical phosphanes where azophenyl and o-semiquinonic ligands are in equatorial plane (Scheme 3). The value of a P = 7.0G is sufficiently lower than that one observed in similar nickel [7] or rhodium [13] complexes (a P = 16.5-25.5G). Such phenomenon of decreasing of phosphorous constant with increasing of metal radius was noted previously [14] for (PPh 3 ) 2 Cu(SQ) and (PPh 3 ) 2 Ag(SQ) (a P = 16.0G for copper, a P = 5.25G for silver complexes).…”

“…Moreover, strong trans-effect of PdAC bond in the complex 1d was found. It results in the difference of NMR chemical shifts of acetilacetonato groups: ACH 3 ( 1 H, d 1.99 and 2.12 ppm, 13 C, d 27.6 and 28.1 ppm) and C@O ( 13 C, d 186.3 and 188.5 ppm) [10], but it was not found in 1a [9].…”

Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

“…There is an inhomogeneous broadening of sulfur components: the high-field component of the sulfur quartet appears more broadened than the low-field one. The measured value of the coupling constant on 33 S is 2.35 G. The hypothesis that this satellite splitting originates from the interaction with the 13 C nuclei (1.11%, S = 1/2, γ = 6.7283 × 10 4 rad G −1 s −1 ) is untenable, since in this case the value of HFS constant on this carbon should be of 7.06 G. Such a value seems to be too large, because coupling constants which are normally observed for 13 C–O atoms in semiquinones, are found in the range of 2.5–3.5 G [16–17]. …”

Large‐Amplitude Thermal Vibration‐Coupled Valence Tautomeric Transition Observed in a Conductive One‐Dimensional Rhodium–Dioxolene Complex

“…Synthesis of [Rh(3,6‐DBDiox‐4‐NO 2 )(CO) 2 ] ∞ (4) : Bubnov et al. reported the synthesis of compound 4 by the reaction of Tl(3,6‐DBSQ‐4‐NO 2 ) with [RhCl(CO) 2 ] 2 in toluene [24] . We prepared compound 4 using our developed redox reaction of [Rh 4 (CO) 12 ] with the corresponding benzoquinone derivative.…”