Complexes of 15-crown-5 and cyclohexano-15-crown-5 with lithium, sodium, and potassium phenoxide having macrocycle: salt ratios of 1:1 and 1:2. The crystal structures of two polymorphs of 15-crown-5•2LiOPh

Abstract

Chem. 66, 2515 (1988).The syntheses, in ethereal solvents, of the complexes of 15-crown-5 and cyclohexano-15-crown-5 with lithium, sodium, and potassium phenoxide are described. The two macrocycles form complexes with lithium and sodium phenoxide with host:guest ratios of 1:2. Potassium phenoxide, however, was complexed by the two macrocycles to give products with macrocycle:salt ratios of 1:l. Crystals of 15-crown-5.2LiOPh were obtained for X-ray diffraction structure determinations. In fact, the crystal structures of tw_o co-crystallizing polymorphs of this complex ( l a and Jb) have been determined. Polymorph l a crystallizes in space group P 1 with a = 11.386(4), b = 11.901(4), c = 10.654(4)A, a = 106.53(3), P = 112.60(3), y = 106.52(3)", and Z = 2. Polymorph l b crystallizes in space group P2'/n with a = 15.355(4), b = 11.642(2), c = 13.595(6) A, P = 104.56(3)", and Z = 4. Both structures were solved by direct methods, and refined by full-matrix least-squares calculations to residuals, R, of 0.053 and 0.055 for polymorphs l a and l b , respectively. The structures of the two polymorphs differ only in the orientation of the phenoxides. The structures show a dimer, (15-~rown-5.2LiOPh)~, which consists of an aggregate of four lithium phenoxide molecules complexed by two 15-crown-5 macrocycles. The two lithiums of each monomeric unit of this dimer have different crystallographic and chemical environments. One lithium is coordinated to all five oxygens of the macrocycle and to one of the phenoxide oxygens while the other lithium is coordinated to only one oxygenof the macrocycle and to three phenoxide oxygens. [Traduit par la revue] Introduction In 1967, Pedersen (I) showed that crown ethers form stable complexes with alkali metal salts. Since then, crown ether complexes have been extensively studied. Several reviews (2-9) have been written on this topic. A large number of alkali

The Remarkable Structural Diversity of Alkali Metal Pyridine-2-thiolates with Mismatched Crown Ethers

“…The crown ether serves to bridge the unusual {K(NC 5 H 4 S-2)} 2 dimeric units, structural motifs resembling the hypothetical structure of dimeric [K 2 (OPh) 2 (15C5) 2 ]. [28] Geometrical data for 3 and 7 are very similar, reflecting high cation coordination numbers. The bridging nature of the two pyridine-2-thiolates in polymeric 7 results in slightly longer K ± S and K ± N distances than those in monomeric 3 (Table 3).…”

Synthesis and structural characterisation of lithium and sodium 2,6-dibenzylphenolate complexes

“…[15][16][17][18] This leads to the formation of "-M-[O-M-] n O-" oligomeric chains, cages, boxes and ladders. 1-3, 19 Alkali metal phenolates can be prepared by two paths, 5 namely direct oxidation of the metal by a phenol accompanied by the evolution of dihydrogen, 20,21 or reaction of a phenol with a suitable transfer reagent, e.g. an alkali metal hydride, organoamide or alkyl.…”

“…1; A and B, respectively). These architectures are exemplified by the unsubstituted lithium phenolates [{Li(OC 6 H 5 )(THF)} 4 ] 25b and [Li 4 (OC 6 H 5 ) 4 (15-crown-5) 2 ], 19 respectively. The coordination requirements of a 15-crown-5 donor, exhibited by all reported 'daisy-chain' tetramers, restrict the l 3-phenolate oxygen bridging necessary for cubic species (A) to l 2 -bridging interactions (B).…”

Dibenzo-15-crown-5 ether and its sodium thiocyanate complex. X-ray crystallographic and NMR studies in the solid phase and in solution

“…The original pioneering work of Pedersen (1) described the synthesis of benzo-15-crown-5 and subsequently a series of articles have appeared dealing with the crystal structure (2) and complexation features of this molecule (3)(4)(5)(6)(7)(8)(9), as well as 15-crown-5 ether itself (10)(11)(12)(13)(14). Also the solid phase 13C NMR features of benzo-15-crown-5 have been reported (15).…”