Two isomers of [1-benzyl-4-(pyridin-2-yl-κN)-1H-1,2,3-triazole-κN 3]dichloridobis(dimethyl sulfoxide-κS)ruthenium(II)

Reaction of [RuCl2(DMSO)4] with 1-benzyl-4-(pyridin-2-yl)-1H-1,2,3-triazole yields two of the four possible isomers of the title compound.


Chemical context
Many 1,2,3-triazole-based ligands have been prepared by copper(I) catalysis of reaction of alkynes with azides; see, for example, Crowley et al. (2010). Continuing our research concerning multifunctional chelating ligands in the construction of supramolecular metal-organic frameworks, we used bis(pyridyltriazole) ligands to make macrocyclic Cu II dimers that have found application in hosting small molecules such as DABCO and oxalate (Pokharel et al., 2013(Pokharel et al., , 2014. As an extension of this work, we were also interested in Ru II pyridyltriazole complexes. Ru II -polypyridine coordination compounds have been employed in dye-sensitized solar cells, optical sensors, and photoredox catalysts (Grä tzel, 2009;Orellana & García-Fresnadillo, 2004;Prier et al., 2013). In contrast, only a small number of Ru II -pyridyltriazole complexes have been examined to ascertain whether incorporation of triazole could result in improvements compared to the polypyridine complexes. Triazole is a stronger acceptor analog of pyridine, because of its three electronegative nitrogen atoms, leading to Ru complexes with different photophysical and electrochemical properties (Schulze et al., 2009;Felici et al., 2009;Elliott et al., 2016). Kumar et al. (2016) used benzylpyridytriazole (bpt, 1) to synthesize the homoleptic Ru II complex Ru(bpt) 3 2+ .
Our intention was to make an Ru II complex with one or two pyridyltriazoles per metal atom along with weakly ligated coordination sites to facilitate other types of chemistry. In this Table 1 Selected bond distances for complexes 2 and 3, the distance between Ru and the mean plane of the pyridyltriazole (Å ), the N1-Ru-N2 angle, and the angle between the pyridyltriazole and benzyl mean planes ( ).  Symmetry code: (i) Àx þ 1 2 ; y À 1 2 ; z.

Figure 1
X-ray structures of 2 and 3. Displacement ellipsoids are drawn at the 50% probability level, and hydrogen atoms are omitted for clarity. Table 3 Hydrogen-bond geometry (Å , ) for 3.
3.031 (4) 164 NMR peak at 7.93 ppm. Li & Flood (2008) took advantage of this C-H(triazole)Á Á ÁCl interaction in preparing a neutral, macrocyclic receptor for chloride ions. Hydrogen bonds to triazole H atoms were also used by White & Beer (2012) in creating a host system that can strongly bind halides. The packing structure of 3 also shows a close interaction of H7, this time with O1 (see Table 3).

Refinement
Crystal data, data collection, and structure refinement details are summarized in Table 4. In both structures, H atoms were placed in idealized positions and treated with a riding model, with C-H distances of 0.95 Å for Csp 2 , 0.99 Å for CH 2 , and 0.98 Å for methyl groups. U iso (H) values were set to either 1.2 or 1.5 (CH 3 ) times U eq of the attached atom. The largest peaks in the final difference maps of 2 and 3 are located 0.914 and 0.887 Å , respectively, from Ru1. For both structures, data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2017 (Sheldrick, 2015b); molecular graphics: Mercury (Macrae et al., 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

κS)ruthenium(II) (2)
Crystal data  Special details 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.

κS)ruthenium(II) (3)
Crystal data Special details 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.