Direct sulfonylation between alkenes and sulfonyl chloride was achieved at room temperature by a visible-light-induced photo­redox process. This method allows the chemoselective synthesis of α-chloro and vinyl sulfone derivatives with moderate to high yields. The selectivity of the reaction was fully controlled by the electronic properties of the alkenes.

A series of lanthanide alkyl complexes supported by a piperazidine-bridged bis(phenolato) ligand were synthesized, and their catalytic activity for the polymerization of L-lactide was explored. The alkane elimination reaction of Ln(CH 2 SiMe 3 ) 3 (THF) 2 with H 2 [ONNO] {H 2 [ONNO] = 1,4-bis(2-hydroxy-3,5di-tert-butylbenzyl)piperazidine} in a 1:1 molar ratio in THF gave the neutral lanthanide alkyl complexes [ONNO]Ln(CH 2 SiMe 3 )(THF) [Ln = Y (1), Lu (2), Yb (3), Gd (4)] in high isolated yields. Treatment of a gadolinium tris(alkyl) complex formed in situ from the reaction of anhydrous GdCl 3 with 3 equiv of Li(CH 2 SiMe 3 ) in THF gave a novel "ate" gadolinium alkyl complex, {[ONNO]Gd(CH 2 SiMe 3 )(μ-Li)-(μ-Cl)} 2 (5). All of these complexes are fully characterized including X-ray structural determination. Complexes 1-4 are isomorphous, monomeric, and THF-solvated. The coordination geometry around the lanthanide metals can be best described as a distorted trigonal bipyramid. Complex 5 is dimeric and unsolvated, and each [ONNO]Gd(CH 2 SiMe 3 ) moiety is connected by two μ-Cl and two μ-Li to form a distorted seven-coordinated capped trigonal-prismatic geometry. It was found that complexes 1-4 are highly efficient initiators for the controlled ring-opening polymerization of L-lactide, giving polymers with high molecular weights and narrow molecular weight distributions, whereas complex 5 exhibited apparently low activity for this polymerization. Complex 1 can also initiate rac-lactide polymerization with high activity, but the stereoselectivity is poor.

A novel hydrated cobalt tetraborate complex NH 4 [Co(NH 3 ) 5 (H 2 O)][B 4 O 5 (OH) 4 ] 2 •6H 2 O, was synthesized by the reaction of NH 4 -borate aqueous with CoCl 2 and its structure was determined by single crystal X-ray diffraction. The crystal system of this complex is orthorhombic, the space group is Pnma, and the unit cell parameters are a＝ 1.2901 (2) nm, b＝1.6817(3) nm, c＝1.1368(2) nm, α＝β＝γ＝90°, V＝2.4742(8) nm 3 , and Z＝4. This compound contains infinite borate layers constructed from [B 4 O 5 (OH) 4 ] 2units via hydrogen bonds. The adjacent polyborate anion layers are further linked together with the octahedral [Co(NH 3 ) 5 (H 2 O)] 3＋ groups through hydrogen bonds to form 3D framework. The 4 NH ＋ groups and guest water molecules are deposited in the empty space of this framework and interact with the layers by extensive hydrogen bonds. Infrared and Raman spectra (4000-400 cm -1 ) of NH 4 [Co(NH 3 ) 5 (H 2 O)][B 4 O 5 (OH) 4 ] 2 •6H 2 O were recorded at room temperature and analyzed. Fundamental vibrational modes were identified and band assignments were made. The middle band observed at 575 cm -1 in Raman spectrum is the pulse vibration of [B 4 O 5 (OH) 4 ] 2-.

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