cis-Bis(2,2′-bipyridine-κ2 N,N′)bis(dimethyl sulfoxide-κO)zinc bis(tetraphenylborate) dimethyl sulfoxide monosolvate

In the mononuclear title complex, [Zn(C10H8N2)2(C2H6OS)2](C24H20B)2·C2H6OS, the ZnII ion is coordinated by four N atoms of two bidentate 2,2′-bipyridine molecules and by the O atoms of two cis-disposed dimethyl sulfoxide molecules in a distorted octahedral geometry. The S atom and the methyl groups of one of the coordinated dimethyl sulfoxide molecules are disordered in a 0.509 (2):0.491 (2) ratio. The crystal packing is stabilized by C—H⋯O hydrogen bonds between the dimethyl sulfoxide solvent molecules and tetraphenylborate anions.

In the mononuclear title complex, [Zn(C 10 H 8 N 2 ) 2 (C 2 H 6 OS) 2 ]-(C 24 H 20 B) 2 ÁC 2 H 6 OS, the Zn II ion is coordinated by four N atoms of two bidentate 2,2 0 -bipyridine molecules and by the O atoms of two cis-disposed dimethyl sulfoxide molecules in a distorted octahedral geometry. The S atom and the methyl groups of one of the coordinated dimethyl sulfoxide molecules are disordered in a 0.509 (2):0.491 (2) ratio. The crystal packing is stabilized by C-HÁ Á ÁO hydrogen bonds between the dimethyl sulfoxide solvent molecules and tetraphenylborate anions.
Financial support from the State Fund for Fundamental Research of Ukraine (grant No. F40.3/041) and the Swedish Institute (Visby Program) is gratefully acknowledged.
cis-Bis (2,2'-bipyridine-2 N,N')bis(dimethyl sulfoxide-O)zinc bis(tetraphenylborate) dimethyl sulfoxide monosolvate S. Tomyn, E. Gumienna-Kontecka, N. I. Usenko, T. S. Iskenderov and E. V. Prisyazhnaya Comment 2,2'-Bipyridine and 1,10-phenantroline are chelating ligands which are widely used in coordination chemistry, in particular, for the preparation of mixed ligand complexes (Fritsky et al., 1998;Kanderal et al., 2005). They are also often used in the synthesis of discrete polynuclear complexes in order to prevent formation of coordination polymers by blocking a certain number of vacant sites in the coordination sphere of a metal ion (Fritsky et al., 2004;Moroz et al., 2010;Penkova et al., 2009). The title compound was obtained unintentionally as the product of an attempted synthesis of a pyrazolate complex of zinc (II) using 2,2'-bipyridine as an additional ligand and sodium tetraphenylborate for better crystallization of the resulting product.
The title compound, [Zn(C 10 H 8 N 2 ) 2 (C 2 H 6 SO) 2 ][(C 24 H 20 B) 2 ].C 2 H 6 SO, consists of a cationic Zn 2+ complex, two tetraphenylborate anions and a solvent dimethyl sulfoxide (DMSO) molecule. The Zn II center is coordinated by four nitrogen atoms of two bidentately coordinated molecules of 2,2'-dipyridine and by the oxygen atoms of two cis-disposed dimethyl sulfoxide molecules. In one coordinated molecule of DMSO the S atom and the methyl groups are disordered with site occupansies of 0.5086 (17) and 0.4914 (17). The central atom adopts a highly distorted octahedral geometry with bond angles of 77.02 (6)-100.08 (6)°. The Zn-O bond lengths in the coordination sphere differ noticeably: the Zn-O1 = 2.0671 (13) Å bond is shorter and the Zn-O2 = 2.1814 (15) Å bond is much longer. Similar differences have been observed before in the related zinc complexes (Lalioti et al., 1998;Persson, 1982;Petrusenko et al., 1997). The Zn-N bond distances fall in the range 2.105 (2)-2.160 (2) Å. The two dipyridine molecules are nearly planar with dihedral angles of -0.9 (3)°a nd 5.7 (3)° between two bonded pyridine rings. The C-C and C-N bond lengths in the bipyridine molecules exhibit normal values (Fritsky et al., 2001;Krämer & Fritsky, 2000;Sachse et al., 2008;Wörl et al., 2005). In the crystal packing the tetraphenylborate anions are linked with the solvate DMSO molecule by C-H···O hydrogen bonds and form layers coplanar the [101] plane.

Experimental
The title compound was obtained accidentally as the product of an attempted synthesis of a zinc complex with 3,5-dimethylpyrazole, using slow evaporation of a dimethyl sulfoxide solution of zinc (II) chloride, sodium tetraphenylborate, 2,2'-bipyridine and 3,5-dimethylpyrazole at room temperature. A solution of ZnCl 2 .4H 2 O (0.208 g, 1 mmol) in DMSO (10 ml) was added to a mixture of 2,2'-bipyridine (0.312 g, 2 mmol) and 3,5-dimethylpyrazole (0.192 g, 2 mmol) in DMSO (10 ml). The mixture was stirred for 15 minutes at room temperature and filtered off. Then sodium tetraphenylborate (0.684 g, 2 mmol) in 5 ml of DMSO was added. The resulting mixture was stirred for 15 minutes, filtered off and set aside at room temperature. Colourless crystals of the title compound suitable for the X-ray analysis were obtained in three days (yield 0.837 g, 66.9%). Analysis calculated for C 74 H 74 B 2 N 4 O 3 S 3 Zn: C 71. 07, H 5.96, N 4.48%, found C 70.92, H 5.84, N 4.39%. supplementary materials sup-2

Refinement
The S atoms and methyl groups of one coordinated dimethylsulfoxide molecule were disordered. This was modelled with two different orientations and from refinement the site occupancies were 0.5086 (17):0.4914 (17). The highest positive peak on the residual map (σ = 0.05 e/Å 3 ) is equal to 0.42 e/Å 3 (0.18 Å from S3) and the deepest hole is -0.48 e/Å 3 (0.74 Å from S3). All H atoms of metyl groups were positioned geometrically and refined using a riding model, with C-H = 0.96 Å and with U iso (H) = 1.5×U eq (C). All H atoms of dipyridine and phenyl rings were positioned geometrically and refined using a riding model, with C-H = 0.93 Å and with U iso (H) = 1.2×U eq (C).  cis-Bis(2,2'-bipyridine-κ 2 N,N')bis(dimethyl sulfoxide-κO)zinc bis(tetraphenylborate) dimethyl sulfoxide monosolvate Crystal data [Zn(C 10

Special details
Experimental. One of the coordinated DMSO molecules was found to be disordered over two positions, its sulfur and carbon atoms were refined with occupancy factors 0.502/0.498.
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.