LANTHANIDE PICRATE COMPLEXES AND PICRIC ACID ADDUCT OF A CALIX[4]ARENE DIAMIDE - SYNTHESES AND STRUCTURES OF [TM(LH(-2))A], [CE(LH(-2))(MEOH)(2)A]CENTER-DOT-HA, [PRLA(3)] AND L-CENTER-DOT-2HA HYLCARBAMOYLMETHOXY)-26,28-DIHYDROXYCALIX[4]ARENE, HA=PICRIC ACID)
Pd. Beer et al., LANTHANIDE PICRATE COMPLEXES AND PICRIC ACID ADDUCT OF A CALIX[4]ARENE DIAMIDE - SYNTHESES AND STRUCTURES OF [TM(LH(-2))A], [CE(LH(-2))(MEOH)(2)A]CENTER-DOT-HA, [PRLA(3)] AND L-CENTER-DOT-2HA HYLCARBAMOYLMETHOXY)-26,28-DIHYDROXYCALIX[4]ARENE, HA=PICRIC ACID), Journal of the Chemical Society. Dalton transactions, (21), 1995, pp. 3455-3466
Reactions of hylcarbamoylmethoxy)-26,28-dihydroxycalix-[4]arene (L) wi
th lanthanide picrates produced 1:1 metal-calixarene complexes incorpo
rating one, two or three picrate moieties, depending on the reaction c
onditions and the lanthanide used. Dichloromethane solutions of L have
been found to extract picric acid (HA) from aqueous solution, resulti
ng in the formation of an L . 2HA adduct. Single crystal structure det
erminations have been carried out on [Tm(LH(-2))A]. 2.5CH(2)Cl(2), [Ce
(LH(-2))(MeOH)(2)A]. HA . H2O, [PrLA(3)]. 2CH(2)Cl(2) . 1.5H(2)O and L
. 2HA . EtOH. The possible variations of these formulae, depending on
the charge distribution within the complexes. are discussed. The cali
xarene is found in a distorted cone conformation in each case. The int
ense colour of some of these complexes appears to correlate with the d
isposition of a picrate moiety close to a calixarene phenyl ring, cons
istent with calixarene-->picrate charge-transfer absorption. The UV/VI
S spectroscopic studies suggest that at least some aspects of the soli
d-state structures are maintained in solution.