Lanthanocene and cerocene alkyl complexes [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln(CH 2 C 6 H 4 -o-NMe 2 ) (Ln = La 3 and Ce 4) were obtained from the salt metathesis of {[η 5 -1,3-(Me 3 C) 2 -C 5 H 3 ] 2 Ln(μ 3 -κ 3 -O 3 SCF 3 ) 2 K(THF) 2 } 2 •THF (Ln = La 1•THF and Ce 2•THF) with LiCH 2 C 6 H 4 -o-NMe 2 . Reactivity of 3 and 4 toward various small molecules provides access to a series of lanthanide derivatives. For example, reactions of 3 and 4 with elemental chalcogens (sulfur and selenium) in 1:1 molar ratio give the lanthanide thiolates {[η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln(μ-SCH 2 C 6 H 4 -o-NMe 2 )} 2 (Ln = La 5 and Ce 6) and selenolates {[η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln(μ-SeCH 2 C 6 H 4 -o-NMe 2 )} 2 (Ln = La 7 and Ce 8). The compounds 3 and 4 react with two equivalents of elemental chalcogens (sulfur and selenium) to afford the lanthanide disulfides {[η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln} 2 (μ-η 2 :η 2 -S 2 ) (Ln = La 9 and Ce 10) and diselenides {[η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln} 2 (μ-η 2 :η 2 -Se 2 ) (Ln = La 11 and Ce 12). The lanthanide disulfides (9 and 10) or diselenides (11 and 12) can also be readily obtained through oxidation of the corresponding lanthanide thiolates (5 and 6) or selenolates (7 and 8) by elemental chalcogens concomitant with the (Me 2 N-o-C 6 H 4 CH 2 ) 2 E 2 (E = S or Se) release. Treatment of 3 and 4 with one equivalent or two equivalents of benzonitrile produces the serendipitous lanthanum and cerium-1-azaallyl complexes [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln[N(H)C(Ph)CHC 6 H 4 -o-NMe 2 ] (Ln = La 13 and Ce 14) or amidine complexes [η 5 -1,3-(Me 3 C) 2 -C 5 H 3 ] 2 Ln[N(H)C(Ph)NC(Ph)CHC 6 H 4 -o-NMe 2 ]•C 7 H 8 (Ln = La 15•C 7 H 8 and Ce 16•C 7 H 8 ), respectively. The compound 15 or 16 can also be readily synthesized by further insertion of one benzonitrile molecule into the 1-azaallyl complex 13 or 14. Insertion of N,N′-dicyclohexylcarbodiimide or phenyl isothiocyanate into Ln−C bonds within 3 and 4 results in the formation of the amidine complexes [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln[CyNC(CH 2 C 6 H 4 -o-NMe 2 )NCy] (Cy = cyclohexyl, Ln = La 17 and Ce 18) or thioamidato complexes [η 5 -1,3-(Me 3 C) 2 C 5 H 3 ] 2 Ln[SC(CH 2 C 6 H 4 -o-NMe 2 )NPh] (Ln = La 19 and Ce 20). All of the new compounds were characterized by various spectroscopic methods, and their solid-state structures were further confirmed by single-crystal X-ray diffraction analyses.

A series of lanthanide chalcogenides {[η5–1,3-(Me3C)2C5H3]2Ln}2(μ-η2:η2-Te2) (Ln = Ce 1, La 2), {[η5–1,3-(Me3C)2C5H3]2Ln­(THF)}2(μ-Se) (Ln = Ce 3, La 4), and {[η5–1,3-(Me3C)2C5H3]2Ln­(THF)}2(μ-Te) (Ln = Ce 5, La 6) can be readily obtained by the reaction of the alkyl complexes [η5–1,3-(Me3C)2C5H3]2Ln­(CH2C6H4-o-NMe2) with elemental selenium or tellurium in the presence of 9-borabicyclo[3.3.1]­nonane (9-BBN). The reaction of the alkyl complexes [η5–1,3-(Me3C)2C5H3]2Ln­(CH2C6H4-o-NMe2) with 9-BBN in 1:2 molar ratio afforded the lanthanide (cyclooctane-1,5-diyl)­dihydroborate complexes [η5–1,3-(Me3C)2C5H3]2Ln­[(μ-H)2BC8H14] (Ln = Ce 7, La 8) concomitant with the (Me2N-o-C6H4CH2)­BC8H14 release, indicating that [η5–1,3-(Me3C)2C5H3]2LnH may be the reactive species for the synthesis of lanthanide chalcogenides. All the new compounds were characterized by various spectroscopic methods, and their solid-state structures were further confirmed by single-crystal X-ray diffraction analyses. Luminescence spectroscopy was also employed to characterize complexes 1–6. The Ce­(III) complexes 3 and 5 display distinct luminescence properties at room temperature, as compared to the corresponding La­(III) complexes 4 and 6. The complex {[η5–1,3-(Me3C)2C5H3]2Ce­(THF)}2(μ-Te) (5) exhibits unexpectedly red emission in solution which is found to depend strongly on the excitation wavelength.

The alkyl complexes [5-1,3-(Me3C)2C5H3]2Ln(CH2C6H4-o-NMe2) (Ln = La 1, Ce 2) react with 9-borabicyclo[3.3.1]nonane (9-BBN) in THF to afford the lanthanum boroxide complex [5-1,3-(Me3C)2C5H3]2La(µ-OBC8H14)(THF) (3) and cerium boroxide complex [5-1,3-(Me3C)2C5H3]2Ce(µ-OBC8H14)(THF) (4)....

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