Bis(alkyl) scandium and yttrium complexes coordinated by an amidopyridinate ligand: synthesis, characterization and catalytic performance in isoprene polymerization, hydroelementation and carbon dioxide hydrosilylation.

New neutral bis(alkyl) Sc and Y complexes [N,Npy,N-]Ln(CH2SiMe3)2(THF)n [n = 0, Ln = Sc (1Sc), Y (1Y); n = 1, Ln = Y (1YTHF)] stabilized by a tridentate monoanionic amidopyridinate ligand were straightforwardly prepared by alkane elimination, upon mixing ligand [N,Npy,N-]H and metal precursor Ln(CH2SiMe3)3(THF)2 in toluene at 0 °C. Depending on the work-up conditions, yttrium bis(alkyl)s were isolated as either a pentacoordinate Lewis base free complex [N,Npy,N-]Y(CH2SiMe3)2 (1Y) or as a hexacoordinate THF adduct [N,Npy,N-]Y(CH2SiMe3)2THF (1YTHF). For the smaller Sc ion the only solvent-free complex [N,Npy,N-]Y(CH2SiMe3)2 (1Sc) was isolated as a pentacoordinate species irrespective of the reaction/work-up/crystallization conditions applied. Complexes 1Ln (Ln = Y, Sc) and 1YTHF were scrutinized as pre-catalysts in ternary catalytic systems Ln/borate/AliBu3 (borate = [HNMe2Ph][B(C6F5)4] or [Ph3C][B(C6F5)4]), applied to isoprene (IP) polymerization, providing moderate activity albeit high selectivity with predominant formation of 1,4-cis polyisoprene (up to 99%). The same complexes proved to be effcient catalysts also for the intermolecular hydrolelementation of styrene with various EH sustrates (pyrrolidine, morpholine, Ph2PH, PhPH2, PhSH) affording linear anti-Markovnikov addition products exclusively. After a preliminary activation by B(C6F5)3, selected bis(alkyl) complexes from this series have been finally used as valuable pre-catalysts for the CO2 hydrosylilation to CH4 in the presence of organosilanes as reducing agents (PhMe2SiH, PhSiH3, Et2MeSiH).

Use of organolanthanides in the catalytic intermolecular hydrophosphination and hydroamination of multiple C-C bonds.

This review covers recent achievements in the intermolecular hydrophosphination and hydroamination of alkenes, dienes and alkynes catalyzed by organolanthanides.

Does the destruction of catecholaminergic neurons in newborn rats influence the modulator function of the cholinergic system?

The influence of the destruction of the catecholaminergic (CA) system on the reactions of neurons of the somatosensory zone of the cortex elicited by stimulation of the sciatic nerve, and on the features of the modulation of these reactions following the stimulation of the region of the basal nuclei (source of cholinergic innervation of the neocortex) and the microiontophoretic application of acetylcholine (ACh), was investigated in mongrel infant rats, 21-31 days of age. It was demonstrated that destruction of the CA system in newborn rats increases the reactivity of neurons somatosensory cortex to sensory stimulation, has no influence on the modulating effect of the cholinergic system, of the forebrain, and leads to intensification of the modulating influence of applied ACh [2].

[Does the destruction of the catecholaminergic neurons in newborn rat pups influence the modulatory function of the cholinergic system?]. / Vliiaet li razrushenie katekholaminergicheskikh neironov u novorozhdennykh krysiat na moduliatornuiu funktsiiu kholinergicheskoi sistemy?

On outbred ratlings aged 21-31 days the influence was studied of the destruction of catecholaminergic (CA) system on the reactions of the neurones of the cortical somatosensory zone, elicited by the stimulation of the ischiatic nerve and modulation of these reactions after stimulation of the basal nuclei area (the source of the neocortex cholinergic innervation) and acetylcholine (ACh) microiontophoretic application. It is shown that destruction of CA system in newborn ratlings increases the reactivity of the somatosensory cortical neurones in 21-31 days old animals to sensory stimulation; it does not influence the efficiency of modulating action of the cholinergic system of the forebrain and leads to the increase of modulating influence of the applicated ACh. It is postulated that as the result of perinatal destruction of CA brain system, in the neocortex a specific morpho-functional organization is formed of structures and processes at which the modulating function of the forebrain cholinergic system turns out, by quantitative criterion, at least, to be compensated.

[Method of determining the activity of cell suspensions as determined by their natural motility]. / Metod opredeleniia aktivnosti suspenzii kletok, obuslovlennoi ikh sobstvennoi podvizhnost'iu.

A new method and setup for determination of motile cell suspension activity are offered. A possibility of measuring the activity with regard to the quota of motile cells and their mean velocity has been shown. Bovine sperm in two diluents was applied as a test object.