Two novel lithium - 15-crown-5 complexes: An extended LiCl chain stabilized by crown ether and a dimeric complex stabilized by hydrogen bonding with water

Two lithium chloride-15C5 (15C5 = 15-crown-5) complexes, [Li(15C5)(mu-Cl)(2 )Li](infinity), 1 and {[Li(15C5)(H2O)]Cl}(2), 2, were synthesized. Their st ructures, characterized by single-crystal X-ray diffraction analyses, are d ictated by the absence of or presence of water. Complex 1, prepared in an a nhydrous environment, is the first example of an extended LiCl chain struct ure. It contains repeating units Li(mu-Cl)Li(15C5) that are connected by ad ditional bridging Cl atoms. One Li has close contacts with one Cl and all f ive O atoms of 15C5 and the other Li with three Cl and one O of 15C5. Howev er, the chain structure cannot form in the presence of water. Instead dimer ic complex 2 was formed when LiCl . xH(2)O (x = 1.14) was the starting mate rial. In this case H2O is coordinated to lithium through a Li-O linkage and is hydrogen bonded to Cl- (H ... Cl). The Li+ cation is coordinated to the five O atoms of 15C5 as well as the O atom from H2O, and the Cl- counteran ion is isolated from Lit by two hydrogen bonds with one H atom each from tw o H2O molecules with H ... Cl distances of 2.30(4) and 2.35(4) Angstrom, re spectively. A crystallographically imposed center of symmetry generates a d imer that resembles a 2:2 anion-paired encapsulate. Crystal data for 1: spa ce group Pna2(1) (no. 33), a 14.974(1) Angstrom, b = 13.553(1) Angstrom, c 7.160(1) Angstrom, V = 1453.0(2) Angstrom(3), Z = 4. Crystal data for 2: sp ace group P2(1)/n (no. 14), a 10.353(1) Angstrom, b = 7.9070(1) Angstrom, c = 17.741 Angstrom beta = 100.50(1)degrees V = 1427.9(2) Angstrom(3), Z = 4 .