Tris(2-cyanoethyl)tin(IV) bromide and tris(2-cyanoethyl)tin(IV) iodide, their structure, properties and reactions with adenosine, AMP and ATP

Complexes [Sn(CH2CH2CN)3I] (1) and [SnBr(CH2CH2CN)3] (2) have been obtained by the oxidation reactions of hexakis(2-cyanoethyl)ditin(III) by means of iodine and bromine. The complexes have been characterized by NMR and IR spectroscopy methods and X-ray crystallography. Both compounds consist of zigzag single-strand chains with a bridging 2-cyanoethyl ligand coordinating via the CH2 group and N atom. The tin atoms are in a distorted trigonal bipyramidal environment with bromo or iodo ligands and a nitrogen atom occupying the axial coordination sites. The Sn(1)–N(3i) distances in complexes 1 and 2 are considerably longer than the tin-equatorial ligand bonds. The molecular and electronic structures and IR spectra of [SnBr(CH2CH2CN)3] mononuclear and [SnBr(CH2CH2CN)3]2 dinuclear fragments of the complex have been studied by the DFT B3LYP method. The calculated interatomic distances for the entity containing a five-coordinate tin atom agree well with those found crystallographically. The compounds in water solutions form trigonal bipyramidal complexes containing aqua and hydroxo axial ligands. The interaction of these complexes with adenosine, 5′-adenosine monophosphate and 5′-adenosine triphosphate has been investigated.

Graphical abstractThe organotin complexes [Sn(CH2CH2CN)3I] (1) and [SnBr(CH2CH2CN)3] (2) have been prepared. In the solid state they form zigzag single-strand chains with a bridging 2-cyanoethyl ligand. The calculated (with the DFT B3LYP method) interatomic distances agree well with those found crystallographically. The compounds in water solutions form trigonal bipyramidal complexes, which interact with 5′-adenosine monophosphate and 5′-adenosine triphosphate via the oxygen atom of the phosphate group.Figure optionsDownload full-size imageDownload as PowerPoint slide