Functionalization of Cage Amines with Pendant Aromatic and Heteroaromatic Substituents

Abstract

Structural studies have confirmed that it is possible to exploit the relatively low nucleophilicity of the “external” amino substituents on the CoIII complex of 1,8‐diaminosarcophagine (“sarcophagine” = sar = 3,6,10,13,16,19‐hexaazabicyclo[6.6.6]icosane) in acylation and alkylation reactions leading to a variety of functionalized cage amine complexes. With the appropriate choice of solvent, all these reactions can be conducted with high efficiency, and the new complexes display properties foreshadowing the application of cage systems in, for example, electroactive polymers.

The preparation and structure of [trans-dichloro-{trans-6,13-dimethyl-6,13-bis-(N,N-dimethylformamidinyl)-1,4,8,11-tetraazacyclotetradecane}nickel(II)] diperchlorate dihydrate

“…The dimensions indicate approximately equal contributions from the canonical forms \CH\NH\CH=N + (Me) 2 and \C\N + H=CH\N(Me) 2 . The dimensions of the formamidinyl group are very similar to those of the N,Nformamidinyl-substituted cobalt(III) cage compound described below [5], and of two uncoordinated formadinium compounds which have been structurally characterized [6,7], which are listed in Table 1 for comparison.…”

“…The dimensions indicate approximately equal contributions from the canonical forms \CH\NH\CH=N + (Me) 2 and \C\N + H=CH\N(Me) 2 . The dimensions of the formamidinyl group are very similar to those of the N,Nformamidinyl-substituted cobalt(III) cage compound described below [5], and of two uncoordinated formadinium compounds which have been structurally characterized [6,7], which are listed in Table 1 A related reaction of an amino substituent on the ligand of a coordination compound with DMF has been reported for a cobalt(III) compound of the amino-capped clathrochelate {1,8-diamino-3,6,10,13,16,19-hexaazabicyclo-[6.6.6]icosane}, (diaminosarcophagine). This was reacted with DMF in the presence of benzoyl chloride and triethylamine in an attempt to benzoylate the amino functions.…”

“…This was reacted with DMF in the presence of benzoyl chloride and triethylamine in an attempt to benzoylate the amino functions. Instead, a N,N-dimethylformamidinyl substituted compound was formed, for which the structure was reported [5]. A reaction mechanism was proposed which involved an initial reaction of benzoyl chloride with DMF to form an electrophylic formamidinyl species, which reacted with the amine groups.…”

A Functionalised Macrobicycle Complex Available for Surface Immobilisation and Protein Grafting

“…[1][2][3] The remarkable properties of these caged metal ions have possible applications in biology, [4][5][6][7][8][9] energy conversion [10][11][12] and materials science. 13,14 For this, it must be possible to covalently attach the cage to other (macro)molecules or surfaces, which then demands the presence of reactive functional groups suitable for such grafting. While the external amino groups of complexes such as [Co(1)] 3+ or [Co(2)] 3+ have been used successfully as such groups in reductive alkylation reactions, [13][14][15][16] reactions at these sites are inhibited by their proximity to the cationic centres.…”

“…13,14 For this, it must be possible to covalently attach the cage to other (macro)molecules or surfaces, which then demands the presence of reactive functional groups suitable for such grafting. While the external amino groups of complexes such as [Co(1)] 3+ or [Co(2)] 3+ have been used successfully as such groups in reductive alkylation reactions, [13][14][15][16] reactions at these sites are inhibited by their proximity to the cationic centres. This problem may be alleviated if the functional group that is to be employed as a linker is more remote from the metal than the amino groups of 1 or 2.…”