Crystal structure of μ2-oxalato-bis[(acetato)(1,10-phenanthroline-κ2N,N')copper(II)], Cu2(C2H3O2)2(C2O4)(C12H8N2)2

Abstract

Source of materialBis(1,5-cyclohexanone) oxal dihydrazone( 0.5m mol) wasd issolved in am ixture of water and ethanol (1:1, 25 mL). Then NaOH (0.01 g, 0.25 mmol) was added and the mixture was stirred for 30 min at room temperature. In the next stage, Cu(Ac) 2 × 2H 2 O (0.5 mmol) and 1,10-phenanthroline (phen, 0.5 mmol) were added. Ther eaction mixture was placed in aP arr-Teflon-lined stainless-steel vessel. It wassealed and heated to 120°C for 17 h, then slowly cooled to room temperature. The resultant solution waskeptat4°C. Blue block-shaped crystals were obtained after two weeks. Experimental detailsAllh ydrogena toms were included in calculated positionsa nd treatedasriding with DiscussionThe synthesis of metal-organic hybrid materials based on Cu(II) hasbeenanactivefield of research over thepast decades due to theinterestininvestigatingtheir structureand theroleofcopper centers in several catalytic activities, to understand the magnetostructural correlations arisingfromthe exchange coupling among Cu(II) sitesand to developnew molecular magnets [1][2][3][4]. Several bridging ligands have been used to construct such compounds [5][6][7]. Among them,polycarboxylate ligands have attracted interest as the organic moiety with avariety of coordination modes and abundant structural motifs [8,9]. The title crystal structure is composed of discrete binuclear units Cu 2 (phen) 2 (CH 3 CO 2 ) 2 (C 2 O 4 ). Each Cu(II)i sc oordinated by three oxygen atoms(O1,O3, O4A) from acetate and oxalate and twon itrogena toms from one phen ligand, forming ad istorted trigonal bipyramid, where N1,O 3a nd O4Aa re locateda tt he equatorial positions while N2 and O1 occupy the axial positions. The bond lengths and angles around the Cu(II) are in the ranges of 1.970(3) -2 .237(3) Åa nd 79.9(1) -1 71.1(1)°, respectively. Cu-O distances are in the range of other Cu(II) m 2 -oxalate complexes [10,11]. The oxalate anion is in m 2 -bridging coordination mode to connect the adjacent Cu1 and Cu1Atoform adimer with aCu×××Cu separation of 5.436 Å, while the phen ligand acts as a typical chelate terminally coordinating the Cu(II) center. The dihedral angle between the planes of Cu1,N 2, C11,C 12,N 1 (mean deviation from plane 0.005 Å) and Cu1,O4A,O3A,Cu1A, O4, O3 (mean deviation from plane 0.067 Å) is 72.9°. Moreover, adjacent dimers are arranged into at wo dimensional network, running parallel to (010), by intermolecular C-H×××Ohydrogen-bonding interactions between phen and carboxyl oxygen atoms.