Yvon Besace

Synthesis, reactivity and X-ray molecular structure of the activated ester complex [(η5-C5H4COONS)Co(CO)2](NS ; N-succinimidyl)

Abstract The title compound [( η 5 -C 5 H 4 COONS)Co(CO) 2 ] ( 2 ) was prepared in high yield (91%) by treatment of the organometallic carboxylic acid [( η 5 -C 5 H 4 COOH)Co(CO) 2 ] ( 1 ) with N-hydroxysuccinimide in the presence of dicyclohexylcarbodiimide. The activated ester complex 2 was identified by spectroscopic methods, in addition its X-ray structure was determined. Compound 2 crystallizes in the triclinic space group P 1 with a = 6.1880(8), b = 9.722(1), c = 10.869(1) A, α = 83.37(1), β = 83.91(1) and γ = 86.30(1)°, V = 645(1) A3 and Z = 2. The stability of the above species 2 and its reactivity as labelling agent for amines and amino-esters are investigated and discussed.

Synthesis, NMR and properties of a novel crown ether dimer: X-ray molecular structure of bis(2, 5-dimethoxy-4,6-dimethyl-1,3-xylyl)-18-crown-4

Abstract The synthesis and complete characterization of the precursor diol 3 and that of the crown ether 4 are reported. Further the X-ray structure of this novel crown ether is included, which provide us with valuable information about its solid-state structure. The title molecule lies about a centre of symmetry. Thus the novel 18-membered macrocycle 4 has a symmetrical configuration. Interestingly, a side view of the molecule shows that the two methoxy groups on each ring are on the same side, face to face and bend over the two arene units in the macrocycle. Finally, preliminary studies of its complexing property towards rhodium cations are presented and discussed. To cite this article: H. Amouri et al., C. R. Chimie 6 (2003).