Ytterbium reacts with 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene (1, dpp-Bian) in 1,2-dimethoxyethane (DME) to give complex (dpp-Bian)Yb(DME)(2) (2). Oxidation of 2 with an 0.5 mol equivalent of dibromostilbene affords dimeric compound [(dpp-Bian)Yb(DME)(mu-Br)](2) (3). Molecular structures of 2 and 3 were determined by single-crystal X-ray analysis. In complex 3 in a DME solution, a temperature-dependent reversible intramolecular electron transfer between the ligand and the metal takes place.

Two new amidines that contain a pendant Lewis base in the side arm, 2-MeOC 6 H 4 NC(tBu)NH(2,6-R 2 C 6 H 3 ) (R = Me, iPr), were synthesized and successfully employed as tridentate ligands for the preparation of the dialkyl rare earth complexes [2-MeOC 6 H 4 NC(tBu)N(2,6-R 2 C 6 H 3 )]Ln(CH 2 SiMe 3 ) 2 (L) n {Ln = Y, Lu; R = Me, iPr; L = thf (n = 2), dme (n = 1)}. These ligands provided enhanced stability for the complexes. The X-ray structure determinations revealed that intramolecular coordination of the 2-MeOC 6 H 4 group is realized if a thf molecule is coordinated to the metal center (Ln = Y, Lu), which results in the coordination number of six. The treatment of complex [2-MeOC 6 H 4 NC(tBu)N(2,6-Me 2 C 6 H 3 )]Lu(CH 2 Si-Me 3 ) 2 (thf) with dme afforded a six-coordinate dme adduct in which the methoxy group of the amidinate ligand has drifted out from the metal coordination sphere. The reaction of [2-MeOC 6 H 4 NC(tBu)N(2,6-iPr 2 C 6 H 3 )]Y(CH 2 SiMe 3 ) 2 (thf) with[a] G. A. Razuvaev

A series of Ln(II) and Ca(II) bis(alkyl) complexes with bulky benzhydryl ligands, [(p-tBu-C 6 H 4 ) 2 -CH] 2 M(L n ) (M = Sm, L = DME, n = 2 (1); M = Sm, Yb, Ca, L = TMEDA, n = 1 (2, 3, 4), were synthesized by the saltmetathesis reaction of MI 2 (THF) n (n = 0−2) and [(p-tBu-C 6 H 4 ) 2 CH] − Na + . In complex 1, the benzhydryl ligands are bound to the metal center in η 2 -coordination mode. Unlike complex 1, in isomorphous complexes 3 and 4, due to the coordination unsaturation of the metal center, the both benzhydryl ligands coordinate to the metal in η 3 -fashion. In complex 2, one ligand is η 3 -coordinated while the second one is η 4 -coordinated to the Sm(II) ion. Complexes 2−4 demonstrated unprecedented thermal stability: no evidence of decomposition was observed after heating their solutions in C 6 D 6 at 100 °C during 72 h. Complex 1 behaves differently: thermolysis in C 6 D 6 solution at 75 °C results in total decomposition in 8 h. Addition of DME promotes decomposition of 2−4 and makes it feasible at 40 °C. Complexes 1−4 demonstrated high catalytic activity and excellent regio-and chemoselectivities in intermolecular hydrophosphination of double and triple C−C bonds with both primary and secondary phosphines. Complexes 2 and 3 enable addition of PhPH 2 toward the internal CC bond of Z-and E-stilbenes with 100% conversion under mild conditions. Double sequential hydrophosphination of phenylacetylene with Ph 2 PH and PhPH 2 was realized due to the application of Yb(II) complex as a catalyst.

The reactions of the bis(alkyl) complexes [Ap*Ln(CH2SiMe3)2(thf)] (Ln = Y, Lu) with both PhSiH3 and H2 result in selective assembly of the novel trinuclear rare-earth alkyl hydrido clusters [(Ap*Ln)3(μ2-H)3(μ3-H)2(CH2SiMe3)(thf)2]. Both cluster compounds are single-component ethylene polymerization catalysts.

Acknowledgment. This work has been supported by the Russian Foundation for Basic Research (Grant Nos. 08-03-00391-a, 06-03-32728). Thanks are also due to the European Commission (NoE IDECAT, NMP3-CT-2005-011730) and the Ministero dell'Istruzione, dell'Universita `e della Ricerca of Italy (NANOPACK -FIRB project no. RBNE03R78E) for support.Supporting Information Available: Tables and CIF files giving crystallographic data for the compounds N 2 Xyl Y(CH 2 SiMe 3 )(THF) (6) and [N 2 Ph Y(µ-H)(THF)] 2 (7). This material is available free of charge via the Internet at http://pubs.acs.org. OM801044H

ansa-Bis(amidinate) ligands with a rigid o-phenylene linker, C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)H}2 (R = Me (1), iPr (2)), were successfully employed for the synthesis of rare-earth chloro and alkyl species. The reaction of dilithium derivatives of 1 and 2 with LnCl3 (Ln = Y, Lu) afforded the monomeric bis(amidinate) chloro lanthanide complexes [C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)}2]Y(THF)(μ-Cl)2Li(THF)2 (R = Me (3), iPr (5)) and [C6H4-1,2-{NC(tBu)N(2,6-Me2C6H3)}2]LuCl(THF)2 (4). Bis(amidinate) ligands in complexes 3 and 4 are coordinated to the metal atoms in a tetradentate fashion, while the bulkier ligand in 5 is tridentate. The alkane elimination reactions of 1 and 2 with equimolar amounts of (Me3SiCH2)3Ln(THF)2 (Ln = Y, Lu) allowed us to obtain the monoalkyl complexes [C6H4-1,2-{NC(tBu)N(2,6-R2C6H3)}2]Ln(CH2SiMe3)(THF) n (Ln = Y, R = Me, n = 1 (6); Ln = Lu, R = Me, n = 1 (7); Ln = Y, R = iPr, n = 2 (8)). The kinetics of thermal decomposition of complexes 6–8 were measured, and for 6 the activation energy was obtained from the temperature dependence of the rate constants (E a = 67.0 ± 1.3 kJ/mol). Complexes 6 and 7 turned out to be inert toward H2 and PhSiH3. Surprisingly, complex 8 was inert toward H2 and PhSiH3 but rapidly cleaved C–O bonds of DME. The reaction resulted in the formation of the methoxy complex {[C6H4-1,2-{NC(tBu)N(2,6-iPr2C6H3)}2]Y(μ2-OMe)]}2(μ2-DME) (9) and methyl vinyl ether.

Among the Ln[15MC CuRha -5] metallacrowns (MC; Rha = R-substituted hydroximate ligands), the simple glycinehydroximate (Glyha) complex is presented as the primary model for studying various aspects of the guest interaction with the Ln III ion. We report a one-pot synthesis of several glycinehydroximate LnL[15MC CuGlyha -5] derivatives in the presence of calcium compounds. The complexes with biden-II Glyha -5](NO 3 ) 2 (3), and biden-[a] G.A. Razuvaev 5202 tate lactate Gd(CH 3 CHOCOO)[15MC Cu II Glyha -5]Cl 2 [4(Gd)]have been prepared and characterized by X-ray analysis. The lactate was chosen as an example of the essential oxyanions that exist as metabolites in all living organisms. We examined the lanthanide-induced NMR spectroscopy shifting ability of a series of lactate 4(Ln) metallacrown complexes (Ln = La, Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, or Dy). The corresponding Gd III complex was characterized by 1 H NMR spectroscopy relaxometric techniques in aqueous media. II Glyha -5](NO 3 ) 2 can be easily prepared by a onepot method in the presence of calcium compounds. [15] Herein, we have developed this synthetic strategy when pre-Scheme 2. Synthetic pathway to nitrate 1.

Oxidation of tin(IV) o-amidophenolate complexes [Sn(ap)Ph(2)] (1) and [Sn(ap)Et(2)(thf)] (2) (ap=dianion of 4,6-di-tert-butyl-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone (ImQ)) with molecular oxygen and sulfur in toluene solutions was investigated. The reaction of oxygen with 1 at room temperature forms a paramagnetic derivative [Sn(isq)(2)Ph(2)] (3) (isq=radical anion of ImQ) and diphenyltin(IV) oxide [{Ph(2)SnO}(n)]. Interaction of 1 with sulfur gives another monophenyl-substituted paramagnetic tin(IV) complex, [Sn(ap)(isq)Ph] (4), and the sulfide, [Ph(3)Sn](2)S. The oxidation of 2 with oxygen and with sulfur proceeds through the derivative [Sn(isq)(2)Et(2)] (7), which undergoes alkyl elimination to give two new tin(IV) compounds, [Sn(ap)(isq)Et] (5) and [Sn(ap)(EtImQ)Et] (6) (EtImQ=2,4-di-tert-butyl-6-(2,6-diisopropylphenylimino)-3-ethylcyclohexa-1,4-dienolate ligand), respectively, along with the corresponding alkyltin(IV) oxide and sulfide. Complexes 3-5 and 7 were studied by EPR spectroscopy. The structures of 3, 4 and 6 were investigated by X-ray analysis.