The literature data on substituent influence on the (51)V, (55)Mn, (57)Fe, (59)Co, (61)Ni, (95)Mo, (103)Rh, (183)W, (187)Os and (195)Pt NMR chemical shifts (delta) and on J (M, P; M = Mn, Fe, Mo, Rh, W, Os) coupling constants have been analyzed for 30 series of the organometallic complexes. It has been established for the first time that the delta and J values depend on the inductive, resonance and polarizability effects of substituents. The polarizability effect is caused by the partial charge on the central M atom. The contribution of this effect ranges from 3 to 86%.

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A series of new tridentate amidines 2-[PhP[double bond, length as m-dash]X]CHNHC(tBu)[double bond, length as m-dash]N(2,6-RCH) (X = O, R = iPr (1); X = S, R = Me (2); X = NPh, R = Me (3); X = N(2,6-MeCH), R = Me (4)) bearing various types of donor PhP[double bond, length as m-dash]X groups in a pendant chain was synthesized. Bis(alkyl) complexes {2-[PhP[double bond, length as m-dash]X]CHNC(tBu)N(2,6-RCH)}Ln(CHSiMe) (Ln = Y, X = O, R = iPr (5); Ln = Er, X = O, R = iPr (6); Ln = Lu, X = O, R = iPr (7); Ln = Y, X = NPh, R = Me (8); Ln = Lu, X = NPh, R = Me (9); Ln = Lu, X = N(2,6-MeCH), R = Me (10)) were prepared using alkane elimination reactions of 1, 3 and 4 with Ln(CHSiMe)(THF) (Ln = Y, Er, Lu) in toluene and were isolated in 45 (5), 62 (6), 56 (7), 65 (8), 60 (9), and 60 (10) % yields respectively. The X-ray diffraction studies showed that complexes 6-8 are solvent free and feature intramolecular coordination of the P[double bond, length as m-dash]X (X = O, NPh) group to the lanthanide ions. The ternary systems 5-10/borate/AlR (borate = [PhNHMe][B(CF)], [PhC][B(CF)], AlR = AliBu, AliBuH; molar ratio = 1/1/10 or 1/1/1, toluene) proved to be active in isoprene polymerization and enable complete conversion of 1000-10 000 equivalents of the monomer into a polymer at 25 °C within 0.5-24 h affording polyisoprenes with polydispersities M/M = 1.22-3.18. A comparative study of the catalytic performance of the bis(alkyl) complexes coordinated by tridentate amidinate ligands containing different pendant donor groups demonstrated that replacement of the PhP[double bond, length as m-dash]O group by PhP[double bond, length as m-dash]NPh leads to a switch of stereoselectivity in isoprene polymerization from cis-1,4 (up to 98.5%) to trans-1,4 (up to 84.8%). And conversely introduction of methyl substituents in the 2,6 positions of the phenyl group of the PhP[double bond, length as m-dash]NPh fragment allows us to restore the 1,4-cis stereoselectivity of the catalytic systems based on bis(alkyl) complex 10 (up to 86.4%).

The literature data on substituent influence on the g factors, hyperfine coupling (hfc) constants (a) of the EPR signals and the spin densities (ρ) have been analyzed for 25 series of the organic radical cations and radical anions as well as of the transition metal complexes. The g, a, and ρ values were first established to depend not only on the inductive and resonance effects but also on the polarizability of substituents which can be characterized by the σ(α) constants. The polarizability effect is caused by the partial charge on the radical center. This effect consists in an electrostatic attraction between the charge and the dipole moments induced by this charge in the substituents. The polarizability contribution ranges up to 92%.