Characterization of silver(I) complexes with diiodo derivatives of pyridine by NMR spectroscopy

Abstract

Reakcijom srebrova(I) nitrata i derivata dijodpiridina (2,5-I2py, 3,5-I2py, 2,6-I2py) u množinskom omjeru 1 : 2 u vodeno-alkoholnom mediju pripravljena su tri nova kompleksa opće formule [Ag(NO3)(I2py)2]. Dobiveni spojevi identificirani su elementnom analizom, a njihova struktura u otopini okarakterizirana je spektrometrijom masa i spektroskopijom NMR. Od 1D tehnika NMR korištene su 1H i 13C ATP, a od 2D homonuklearni 1H-1H COSY te heteronuklearni 1H-13C HMQC i 1H-13C/15N HMBC. U čvrstom stanju, kompleksi su okarakterizirani spektroskopijom IR zračenja. Kristalna i molekulska struktura kompleksa [Ag(NO3)(2,5–I2py)2] određena je i rentgenskom strukturnom analizom. Dobiveni rezultati ukazuju na vezanje srebrovog(I) iona s dvama ligandima preko nesparenog elektronskog para atoma dušika piridinskog prstena. Rentgenska strukturna analiza monokristala spoja [Ag(NO3)(2,5–I2py)2] otkriva da su pored kovalentnih veza (Ag– Npy, Ag–O, Ag–I), u strukturu kristala uključene i nekovalentne halogenske interakcije (O···I–C) koje pridonose stvaranju polimerne strukture spoja.Three novel 1:2 complexes of general formula [Ag(NO3)(I2py)2] were prepared in water-alcohol solution by reaction of silver (I) nitrate with diiodopyridine derivatives (2,5-I2py, 3,5-I2py, 2,6-I2py). All prepared compounds were identified by elemental analysis. Their structure in solution were characterized by mass spectrometry and NMR spectroscopy (1H, 13C ATP, 1H-1H COSY, 1H-13C HMQC, 1H-13C/15N HMBC). In solid state, the complexes were characterized by IR spectroscopy. The crystal and molecular structure of the [Ag(NO3)(2,5–I2py)2] complex was revealed by single crystal X-ray analysis. The obtained results confirmed the binding of silver(I) ion with two ligands via the lone electron pair of nitrogen atoms of the pyridine ring. X-ray structural analysis of [Ag(NO3)(2,5-I2py)2] reveals that beside covalent bonds (Ag–Npy, Ag–O, Ag–I), supramolecular halogen interactions are also present in its crystal structure (O···I–C). Halogen interactions contribute to the final dimensionality by forming polymeric structure of the compound