Novel Lanthanide Coordination Polymers with a Flexible Disulfoxide Ligand, 1,2-Bis(ethylsulfinyl)ethane: Structures, Stereochemistry, and the Influences of Counteranions on the Framework Formations

The reactions of meso-1,2-bis(ethylsulfinyl)ethane (meso-L) with Ln(ClO4)3 [Ln(NO3)3 or Ln(NCS)3] in MeOH and
CHCl3 gave a series of new lanthanide coordination polymers, {[Ln(μ-meso-L)(rac-L)2(CH3OH)2](ClO4)3}n [Ln:  La
(1), Nd (2), Eu (3), Gd (4), Tb (5), Dy (6), and Yb (7)], [Yb(μ-meso-L)1.5(NO3)3]n (8), and [La(μ-meso-L)2.5(NCS)3]n
(9). All the structures were established by single-crystal X-ray diffraction. Complexes 1−7 are isostructural with
infinite single μ-chain structure, in which the L ligands take two kinds of coordination modes:  bidentate chelating
and bis-monodentate bridging. Six sulfur atoms of the sulfoxide groups around each LnIII center adopt alternatively
the same R or S configuration in the chain. In addition, the configuration change of partial ligands occurred from
the meso to the rac form when reacting with Ln(ClO4)3. To our knowledge, this is the first example of disulfoxide
complexes with two kinds of coordination modes and three kinds of configurations (R,R, S,S, and R,S) occurring
simultaneously in the same complex. 8 exhibits single−double bridging chain structure, in which dinuclear
macrometallacycles formed through bridging two YbIII by two meso-L ligands are further linked by another meso-L
ligand. In 9 each LaIII ion is linked to five other LaIII ions by five meso-L ligands to form a 5-connected 2-D (3/4,5)
network containing two types of macrometallacyclic arrays:  quadrilateral and triangle grids. The structural differences
among 1−7, 8, and 9 show that counteranions play important roles in the framework formation of such coordination
polymers. In addition, the luminescent properties of 3 and 5 were also investigated.