cis-[1,4-Bis(diphenylphosphanyl)butane-κ2 P,P′]dichlorido(cyclohexane-1,2-diamine-κ2 N,N′)ruthenium(II) dichloromethane monosolvate

In the title compound, [RuCl2(C6H14N2)(C28H28P2)]·CH2Cl2, the RuII ion is coordinated in a slightly distorted octahedral environment, formed by two cis-oriented chloride ligands, two cis P atoms of a 1,4-bis(diphenylphosphanyl)butane ligand and two cis-chelating N atoms of a bidentate cyclohexane-1,2-diamine ligand. In the crystal, pairs of molecules form inversion dimers via N—H⋯Cl hydrogen bonds. In addition, intramolecular N—H⋯Cl and weak C—H⋯Cl, C—H⋯N, N—H⋯π and C—H⋯π hydrogen bonds are observed. One of the Cl atoms of the solvent molecule is disordered over two sites with refined occupancies of 0.62 (1) and 0.38 (1).

In this work, we report the synthesis and crystal structure of the title complex. The complex cis-[RuCl 2 (chd)(dppb)] is in full cis form ( Fig. 1) with a solvent molecule of dichloromethane. The Ru II ion is in a slightly distorted octahedral environment with a five-membered (chd) ring coordinating via N1 and N2, a seven-membered (dppb) ring coordinating via P1 and P2 as well as two Cl atoms. In the seven-membered ring of dppb the P-Ru-P angle is larger than the ideal value for perfectly octahedral. The 1,2-cyclohexanediamine ring also enforces distortion of the N-Ru-N angle [79.89 (13)°] while the Cl-Ru-Cl angle is closer to ideal [90.73 (4)°]. One Cl atom of the CH 2 Cl 2 solvent is disordered over two positions with a site-occupancy ratio of 0.62 (1):0.38 (1). The molecular conformation and the crystal packing show various intra and intermolecular contacts of the types N-H···Cl, C-H···Cl and C-H···N (Table 1 and Fig. 2). The molecule and crystal structure are further stabilized by intramolecular N-H···π and intermolecular C-H···π interactions ( Table 1).
The values of these interactions are similar to those observed in other ruthenium complexes of the same type (Warad, 2007(Warad, , 2010.

Experimental
1,2-cyclohexanediamine (0.21 mmol) was dissolved in 10 ml of dry dichloromethane and the resultant solution was added drop-wise to a stirred solution of (RuCl 2 (dppb)PPh 3 ) complex (0.20 mmol) dissolved in 10 ml of dry dichloromethane. The reaction mixture was stirred for 5 min at room temperature under inert atmosphere resulting in a change in color from green to light yellow. The resulting yellow solution was concentrated by vacuum to 1 ml followed by addition of 30 ml of diethyl ether to cause desired complex formation as precipitation. The resulting precipitate was collected and recrystallized from dichloromethane/diethyl ether and obtained in analytically pure form.

Refinement
All H atoms attached to C and N atoms except those attached to N1 atom, were fixed geometrically and treated as riding, with C-H = 0.93-0.98 Å and N-H = 0.90 Å and with U iso (H) = 1.2U eq (C or N). The H atoms bonded to N1 were refined independently with U iso = 0.05Å 2 .

cis-[1,4-Bis(diphenylphosphanyl)butane-κ 2 P,P′]dichlorido(cyclohexane-1,2-diamine-κ 2 N,N′)ruthenium(II) dichloromethane monosolvate
Crystal data [RuCl 2 (C 6 H 14 N 2 )(C 28 H 28 P 2 )]·CH 2 Cl 2 M r = 797.53 Monoclinic, P2 1 /c Hall symbol: -P 2ybc a = 12.419 (7)  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 > σ(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.  (6)