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Alkali and alkaline-earth metal complexes of 4′-acetobenzo-15-crown-5 and 4′-acetobenzo-18crown-6 have been prepared and characterised by i.r. and n.m.r. spectroscopy. The crystal and molecular structure of 4′-aceto-benzo-18-crown-6·Sr[ClO4]2(the title complex) has been determined. No intermolecular interaction between the metal ion and the aceto-group has been observed. The reaction of several metal salts with 4′-(bromoaceto)benzo-15-crown-5 gives rise to internal nucleophilic displacement of the bromine by the anion to yield novel crown ethers.

Novel alkaline earth metal thiocyanate complexes are formed by the template condensation of furan-2,5-dicarbaldehyde with 1,11-diamino-3,6,9-trioxaundecane and 1,5-bis(2-aminophenoxy)-3-oxapentane; the X-ray structure of aqua-(3,15-diaza-6,9,12,20-tetraoxabicyclo[15,2,1]eicosa-2,15,17,19-tetraene)-di-isothio-cyanatostrontium(II) has been determined.

Novel alkaline earth metal thiocyanate complexes are formed by the template condensation of 1,11-diamino-3,6,9-trioxaundecane with pyridine-2,6-dicarbaldehyde; the X-ray structures of (3,15,21-triaza-6,9,12-trioxabicyclo [15.3.1]heneicosa-1(21), 2, 15, 17, 19-pentaene)di-isothiocyanatocalcium(II) and aqua-(3,15,21-triaza-6,9,12-trioxabicyclo[15.3.1]heneicosa-1(21),2,15,17,19-pentaene)di-isothiocyanatostrontium(II) have been determined and the ready exchange of alkaline earth cations for lead(II) in these complexes is reported.