In fact, the oxime group is of great interest in coordination chemistry due to combination of such properties as strong donor capacity, possibility to provide bridging way of coordination giving rise to versatility of oligo- and polynuclear structures and capability to mediate exchange interactions between paramagnetic centers.schemeScheme1. PEN (n = 2), PAP (n = 3), PAPT (n = 5), PAH (n = 6), PAHP (n = 7)In the present work, the matter of consideration is a thorough investigation of novel coordination compounds on the base of polydentate ligands containing a couple of equivalent oxime-and-amide donor sets connected by polymethylene linkers of different length (Scheme 1). The composition of novel Cu(II) coordination compounds has been determined by elemental analysis, IR-spectroscopy and X-ray analysschemeFig.1. Molecular structure of [{Cu(PAH-H)(NO3)(CH3OH)}2]EPR and UV-VIS study throughout a wide pH range in combination with potentiometric titration has been conducted in order to determine peculiarities of complex speciation in methanol solutions upon complexation of PAPT, PAH and PAHP with Cu(II). ESI mass-spectrometric study has clearly shown existence of mono- and binuclear species in solutions, whereas results of MALDI mass-spectrometric study with use of different matrices appeared not to be very informative for such kind of systems showing only signals peculiar to mononuclear species. The X-ray single crystal study of five new coordination compounds confirmed suggested bis(bidentate) coordination mode of the ligands and demonstrated the preferential formation of binuclear species containing metallomacrocyclic cavities of different size (Fig.1). A short intramolecular hydrogen bond has been considered to be a key factor in the self-assembly of the systems studied here.