Tricyclic ligands on cyclam core and X-ray crystallographic structure of hexachloro-(1,11:4,8-bis(pyridine-2,6-diyl-bis(2-(N-(2-formidoylethylene)carbamoyl)ethylene))-1,8-diazonia-4,11-diazacyclotetradecane) – dimanganese(II) dimethanol dihydrate solvate

Abstract

Cyclam was tetrafunctionalized by addition of four equivalents of methyl acrylate followed by condensation with four equivalents of ethylenediamine to give the derivative 3 . This compound was further condensed with 2,6-pyridinedicarbaldehyde and 2,6-phthaldialdehyde resulting in formation of three kinds of tricyclic products. Three of them were characterized crystallographically as well as dimanganese(II) complex of one of the isomeric tricycle. ► Cyclam macrocycle can be functionalized by consecutive addition four methyl acrylates followed by condensation with ethylenediamine. ► The tetrafunctionalized cyclam condensates with 2,6-aryl-dialdehydes to form three isomeric tricyclic ligands. ► Manganese(II) incorporation into tricyclic ligand leads to dimanganese(II) complex and protonation of cyclam core. ► The dimanganese(II) complex is valuable synthon to obtain trinuclear mixed-metal-ion complexes. The synthesis of tricyclic compounds on functionalized cyclam core is described. The addition of four methyl acrylate molecules and consecutive condensation of this derivative with ethylenediamine resulted in formation of 1,4,8,11-tetrakis(2-( N -(2-aminoethyl)carbamoyl)ethyl)-1,4,8,11-tetraazacyclotetradecane ( 3 ). Compound 3 was the substrate for further condensation with dialdehydes: iso -phthaldialdehyde and 2,6-pyridinedicarbaldehyde, resulting in spontaneous macrocycle ring closure to give tricyclic derivatives: 1,11:4,8-bis(benzene-1,3-diyl-bis(2-( N -(2-formidoylethylene)carbamoyl)ethylene))-1,4,8,11-tetraazacyclotetradecane ( 4 ) in the reaction of 3 with iso -phthaldialdehyde and three isomers: 1,4:8,11-bis(pyridine-2,6-diyl-bis(2-( N -(2-formidoylethylene)carbamoyl)ethylene))-1,4,8,11-tetraazacyclotetradecane ( 5A ), 1,11:4,8-bis(pyridine-2,6-diyl-bis(2-( N -(2-formidoylethylene)carbamoyl)ethylene))-1,4,8,11-tetraazacyclotetradecane ( 5B ), and 1,8:4,11-bis(pyridine-2,6-diyl-bis(2-( N -(2-formidoylethylene)carbamoyl)ethylene))-1,4,8,11-tetraazacyclotetradecane ( 5C ) when 2,6-pyridinedicarbaldehyde was used. The compounds 4 , 5B , and 5C were identified crystallographically. The isolated 5A converted in solution into the mixture of 5B and 5C as monitored by the 1 H NMR spectroscopy. The tricycle 5 is able to accept two manganese(II) metal ions by reacting with manganese(II) dichloride with simultaneous diprotonation of 5 . Structure of the resulting Mn 2 (5BH 2 )Cl 6 ·(CH 3 OH) 2 (H 2 O) 2 was determined crystallographically.