154845-71-3Relevant academic research and scientific papers
Chemistry of Rh(I) complexes based on mesogenic 3,5-disubstituted pyrazole ligands. X-ray crystal structures of 3,5-di(4-n-butoxyphenyl)pyrazole (Hpzbp2) and [Rh(μ-pzR2)(CO)2]2 (R = C6H4OCnH2n+1, n = 10, 12) compounds. Part II
Torralba,Cano,Campo,Heras,Pinilla,Torres
, p. 150 - 161 (2007/10/03)
Four new 3,5-disubstituted pyrazoles HpzR2 containing long-chain 4-n-alkyloxyphenyl substituents [R = C6H4OCnH2n+1; n=4 (1), 6 (2), 12 (5), 14 (6)] have been prepared and characterised. All of them showed mesomorphic behaviour,the stability and the range of the mesophases increasing with the length of the chain on the pyrazole. The X-ray structure of Hpzbp2 (1) showed a highly linear molecular shape. Related results were deduced for the remained HpzR2 and the structural consequences agree with the observed mesomorphic properties. The mesogenic pyrazoles HpzR2 (1-6) were used as ligands towards [RhCl(CO)2] and [Rh(CO)2] fragments. [RhCl(CO)2(HpzR2)] complexes (7-12) showed some physical properties dependant on the long-chained pyrazoles, and related to different molecular arrays in the solid state. In all cases these compounds evolved to [Rh(μ-pzR2)(CO)2]2 in solution. The pyrazolate Rh(I) complexes [Rh(μ-pzR2)(CO)2]2 (3-18) had the usual boat conformation, as deduced by the crystal structure of two of these derivatives [n =10 (16), 12 (17)]. The packing arrangement has both layer and columnar characteristics. No mesophases have been detected for any of the Rh(I) complexes.
