Treatment of [Cp 2 Ln(µ-Me)] 2 with 2 equiv of elemental sulfur in toluene at room temperature leads to the formation of the methylthiolate complexes [Cp 2 Ln(µ-SMe)] 2 [ Ln ) Yb (1a), Y (1b), Er (1c), Dy (1d)] in good yields. While reaction of Cp 2 Y( n Bu) with elemental sulfur in 1:1 stoichiometric ratio under the same conditions yields [(Cp 2 Y) 2 (µ 3 -S)(THF)] 2 (2a) as the metal-containing product with the extrusion of n BuS n Bu and n BuSS n Bu, the corresponding insertion intermediate [Cp 2 Y(µ-S n Bu)] 2 (1e) could be isolated only by decreasing the relative amount of S 8 under more mild reaction conditions. Furthermore, [Cp 2 Yb(µ-SEt)] 2 reacts with 2 equiv of sulfur to give a mixture of [(Cp 2 Yb) 2 (µ 3 -S)(THF)] 2 (2b) and [Cp 2 Yb-(THF)] 2 (µ-η 2 :η 2 -S 2 ) (3). 2b and 3 can also be prepared from the reaction of [Cp 2 Yb(µ-Me)] 2 with excess elemental sulfur in THF. All these results demonstrate that lanthanocene thiolate complexes are unstable in solution with S 8 , and the nature of the alkyl ligands and reaction conditions has a great influence on the final product structures from the reaction of lanthanocene alkyls with elemental sulfur and provides an easy access to trivalent lanthanocene thiolate, sulfide, and disulfide complexes as well as thioethers and organic disulfides. Complexes 1-3 were characterized by elemental analysis and IR and mass spectroscopies. The structures of complexes 1a, 1e, 2a, 2b, and 3 are also determined through X-ray single-crystal diffraction analysis.

A series of 1,2,4-diazaphospholide (dp(-)) samarium complexes with a variety of coordination modes were prepared via the metathesis reaction of SmCl3(THF)3 and potassium 3,5-disubstituted 1,2,4-diazaphospholide or by the reaction of Sm[N(SiMe3)2]3 and 3,5-diphenyl-1,2,4-diazaphosphole.

A series of new functionalized amido complexes of ytterbium, [Cp 2 YbNHR] 2 (R ) 8-quinolyl(Qu) (1a), 2-pyridyl(Py) (1b), 2-aminophenyl (1c), 3-amino-2-pyridyl (1d), and Cp 2 Yb[NHC 6 H 4 (CH 2 NH 2 -2)] (1e), have been synthesized by metathesis of Cp 2 YbCl and the corresponding amido lithium salts. Their reactivity toward carbodiimides has been investigated, in which multiple N-H activation behavior for metal-bound neutral NH 2 and anionic nitrogen-containing fragments, a property that is expressed without dissociation from the lanthanide center, is observed. These results provide an alternative mechanistic insight for the metal-mediated mono-and diguanylation of primary amines and elucidate factors that affect the chemo-and regioselectivities of the addition and protonation steps. Reaction of 1a with 2 equiv of RNdCdNR [R ) cyclohexyl (Cy), isopropyl ( i Pr)] leads to the formal insertion of carbodiimide into the N-H bond of the Yb-bonded amido group to yield Cp 2 Yb[η 1 :η 2 -RNC(NHR)NQu] 2 [R ) Cy (2a), i Pr (2b)]. Interestingly, treatment of 1b with RNdCdNR affords the unexpected products (Cp 2 -Yb) 2 [µ-η 2 :η 2 -PyNC(NR) 2 ](THF) [R ) Cy (3a), i Pr (3b)], representing the first example of dianionic guanidinate lanthanide complexes. The reaction of 1c with 2 equiv of RNdCdNR in THF at room temperature leads to the isolation of the single N-H addition products Cp 2 Yb[η 1 :η 2 -RNC(NHR)NC 6 H 4 -NH 2 -2] [R ) Cy (4a), i Pr (4b)] in satisfied yields, while treatment of 1c with 4 equiv of RNdCdNR under the same conditions gives the double N-H addition products Cp 2 Yb[η 1 :η 2 -RNC(NHR)NC 6 H 4 -{NC(NHR) 2 -2}] [R ) Cy (5a), i Pr (5b)], via the intraligand proton transfer from chelating NH 2 to the guanidinate group of 4 to give new amido intermediates, followed by a second RNdCdNR insertion into the N-H bond of the resulting amido groups. Complexes 5 can also be obtained by reacting 4 with 1 equiv of RNdCdNR. The double-addition product Cp 2 Yb[η 1 :η 2 -CyNC(NHCy)NC 5 H 3 N{NC(NHCy) 2 -3}] (6) could be obtained as red crystals from the 1:4 reaction between 1d and CyNdCdNCy in 63% yield. Interestingly, 6 can be converted into (Cp 2 Yb) 2 [η 2 :η 3 -(CyN) 2 CNC 5 H 3 N{NC(NHCy) 2 -3}] (7) under reflux in THF and with liberation of a neutral diguanidine, C 5 H 3 N(NC(NHCy) 2 )-2,3. A preference of the proton transfer to the second carbodiimide insertion into the N-H bond in the formation of 5 and 6 has been confirmed by the fact that treatment of weaker acidic 1e with an excess of carbodiimides in THF/ toluene, even with prolonged heating, provides only the monoaddition product Cp 2 Yb[η 2 :η 1 -CyNC(NHCy)-NC 6 H 4 (CH 2 NH 2 -2)] [R ) Cy (8a), i Pr (8b)]. All complexes were characterized by elemental analysis and spectroscopic properties. The structures of all complexes except 2b, 3b, 4a, and 5b were also determined through X-ray crystal diffraction analysis.

A new methylene-bridged ligand incorporating both indenyl and pyrrolyl moieties, (C 9 H 7 )CH 2 (R-C 4 H 3 -NH) (1), was prepared. Reaction of LnI 2 with 1 equiv of [(C 9 H 6 )CH 2 (R-C 4 H 3 N)]Li 2 (THF) x in THF, followed by recrystallization in DME, gave the organolanthanide(II) complexes (THF) x under the same conditions generated [(η 5 -C 9 H 6 )CH 2 (µ-η 1 :η 3 -C 4 H 3 N)Er(µ 3 -Cl)(µ-Cl)Li(THF) 2 ] 2 (5). Reaction of 4 with 2 equiv of n-butyllithium ( n BuLi) and subsequently with N,N′dicyclohexylcarbodiimide (CyNdCdNCy) gave the carbodiimide insertion into the Sm-C bond product 6), while treatment of 4 with 2 equiv of NaN-(SiMe 3 ) 2 in THF followed by reacting with CyNdCdNCy gave the carbodiimide insertion into the Sm-N bond product 7). These complexes were characterized by IR and 1 H NMR spectra and elemental analyses. Furthermore, the structures of all these compounds were also confirmed by X-ray diffraction analyses.

An efficient method for the formation of SiCl3 radicals by the reaction of abundant and cheaper chlorosilanes with DyI2 has been established, not only demonstrating new distinctive reactivities of solvated DyI2 but also suggesting that the presence of lanthanide ions can improve the selectivity of some silyl radical-catalyzed reactions.