Low-dimensional Compounds Containing Cyano Groups. XI. Preparation, Crystal Structure and Properties of Two Copper(II) Dicyanamide Complexes with PF 6 − Anions

Abstract

From the reaction mixtures containing Cu(NO 3 ) 2 , Na[N(CN) 2 ], KPF 6 and 2,2¢-bipyridine (bpy) or 1,10-phenanthroline (phen) in 1:1:1:2 molar ratios, [Cu(bpy) 2 N(CN) 2 ][Cu(bpy) 2 (H 2 O)](PF 6 ) 3 (1b) and [Cu (phen) 2 N(CN) 2 ]PF 6 (1p) complexes were isolated. Measured i.r. spectra confirm the presence of all functional groups in both complexes and, moreover, they indicate monodentate coordination of dicyanamide through the cyano nitrogen atom in (1p). The structure of (1b) contains two crystallographically independent complex cations. In both, Cu is coordinated by two chelating bpy molecules, and either dicyanamide anion or water molecule fills the fifth position, completing the basal plane. The Cu II atoms in (1p) are coordinated by two chelating phen ligands and by one dicyanamide anion in the equatorial plane. Hexafluorophosphate anions in (1b) and (1p) remain uncoordinated. Besides the ionic forces in both structures, the structure of (1b) is stabilized by strong OAHÁ Á ÁF and OAHÁ Á ÁN hydrogen bonds and, moreover, both structures are stabilized by weak CAHÁ Á ÁF hydrogen bonds and possible p-p interactions between pyridine rings of bpy or phen molecules.

Synthesis, crystal structures and DNA-binding properties of two new mononuclear copper(II) complexes

“…3. The Cu coordinates to four N atoms from two Me 2 bpy molecules and one O atom (O1) of water in a trigonal bipyramidal geometry with s value of 0.72 (Table 3), which is similar to the literature reported compounds containing the central Cu(bpy) 2 O [26][27][28]. In the polyhedron of Cu atom, the two out-of-plane Cu-N1 and Cu-N4 distances (mean 1.9376 Å ) are significantly different and almost linear (see Table 3), with N1-Cu-N4 = 178.40°.…”

Low-dimensional compounds containing cyano groups. XV. Preparation, crystal structure and spectral properties of three copper(II) nitrosodicyanomethanide complexes

“…The two equatorial distances (Cu1-N20 and Cu1-N40) are very similar, too, but they are substantially longer than the axial Cu-N distances (0.136 Å on average). This feature is generally observed for compounds containing the [Cu(L) 2 X] cation, where L is bipy, and X is Cl -, Br -or I - [23]; L is phen, and X is Cl - [24], Br - [25] or H 2 O [26]; L is phen or bipy, and X is a pseudohalide monoanion [9]; and L is phen or bipy and X is dca [11]. The third equatorial distance (Cu1-O1 = 1.975(3) Å ) is much shorter than the other two equatorial distances and is very similar to the axial distances.…”

“…, and dca is dicyanamide [11], and [Cu(tn) 2 dca]ClO 4 compounds, where tn is 1,3-diaminopropane [12]. We have found that the geometry in these compounds depends mostly on the rigidity of L. Geometry of the central atom in compounds with highly rigid phen is only slightly distorted trigonal bipyramidal, while it is more distorted trigonal bipyramidal in compounds with less rigid bipy and slightly distorted square pyramidal when L is a flexible tn ligand.…”

Low-dimensional compounds containing cyanido groups. XXIX. Crystal structures, spectral and magnetic properties of five [Cu(L)2X]C(CN)3 complexes (L = 2,2′-bipyridine or 1,10-phenanthroline; X = Cl−, Br− or CH3COO−)

“…In our previous work, we have prepared and studied complexes with X = N(CN) 2 -and ONC(CN) 2 -with the aim to characterize the shape of coordination polyhedra (SCP) around the Cu(II) atoms [2,3] and to find possible reasons leading to different SCP. The obtained results showed that the preferred SCP for compounds with phen is close to TBP, whereas that for compounds with bpy is close to TEP.…”

“…The obtained results showed that the preferred SCP for compounds with phen is close to TBP, whereas that for compounds with bpy is close to TEP. Tricyanomethanide (tcm) anion C(CN) 3 -, as a member of nonlinear pseudohalides, can coordinate similarly as N(CN) 2 -and ONC(CN) 2 -anions [4]. Therefore, to verify the findings about SCP, we have attempted to prepare analogous complexes of general [Cu(L) 2 C(CN) 3 ]Y formula.…”