A one-dimensional bromide-bridged PtII/PtIV mixed-valence complex with a 2-bromo-ethane-sulfonate counter-ion.

Nobuyuki Matsushita,Ayako Taira,Yoshiya Taoka

doi:10.1107/s2056989017009598

Abstract

The title salt, catena-poly[[[bis-(ethyl-enedi-amine)-platinum(II)]-μ-bromido-[bis(ethyl-enedi-amine)-platinum(IV)]-μ-bromido] tetra-kis-(2-bromo-ethane-sulfon-ate) dihydrate], {[PtIIPtIVBr2(C2H8N2)4](C2H4BrSO3)4·2H2O} n , crystallizes in the space group P21212. It has a linear chain structure extending parallel to the c axis, composed of square-planar [Pt(en)2]2+ and elongated octa-hedral trans-[PtBr2(en)2]2+ cations (en is ethyl-enedi-amine) stacked alternately and bridged by the Br atoms. The Pt site of the [PtII/IV(en)2] unit is located on a general position. The Br site, which is also located on a general position, is equally disordered over two positions. The Pt and Br atoms form a slight zigzag ⋯Br-PtIV-Br⋯PtII⋯ chain, with PtIV-Br bond lengths of 2.453 (2) and 2.491 (3) Å, PtII⋯Br contacts of 3.069 (2) and 3.032 (3) Å, and PtIV-Br⋯PtII angles of 178.06 (13) and 177.70 (13)°. The mixed-valence state of the Pt site is expressed by the parameter δ = (PtIV-Br)/(PtII⋯Br), with values of 0.799 and 0.822 for the two independent Br atoms. In the crystal, N-H⋯O and O-H⋯O hydrogen bonds between the amine groups of the Pt complex chains, the sulfonate groups and water mol-ecules of crystallization, stabilize the cationic columnar structure.

Highlights

HÁ Á ÁO hydrogen bonds between the amine groups of the Pt complex chains, the sulfonate groups and water molecules of crystallization, stabilize the cationic columnar structure
The metal–halogen distances in compounds with MX-chain structures characterize the physical properties based on the mixed-valence electronic state
The Br atoms are not located at the exact midpoint between adjacent Pt atoms and are disordered over two sites close to the midpoint

Summary

Chemical context

The metal–halogen distances in compounds with MX-chain structures characterize the physical properties based on the mixed-valence electronic state. The structural parameters indicating the mixed-valence state of the Pt atom, expressed by = (PtIV–Br)/(PtIIÁ Á ÁBr), are 0.799 and 0.822 for Br1 and Br2, respectively. These values are slightly smaller than those of [Pt(tn)2][PtBr2(tn)2](BF4) (tn is 1,3-diaminopropane; 0.826; Cannas et al, 1983), [Pt(en)2][PtBr2(en)2](ClO4) (0.827 for a higher temperature phase at 313 K exhibiting space-group type Ibam and 0.828 for a lower temperature phase at 298 K exhibiting space-group type P21/m; Toriumi et al, 1993), and comparable with those of. [Pt(NH3)4][PtBr2(NH3)4](HSO4) (0.817; Tanaka et al, 1982), [Pt(tn)2][PtBr2(tn)2](ClO4) (0.815; Cannas et al, 1983), [Pt(en)2][PtBr2(en)2](HSO4) (0.813; Matsushita et al, 1992) but larger than those of [Pt(CH3CH2NH2)4][PtBr2(CH3CH2NH2)4]Br4 (0.787 and 0.599; Endres et al, 1980)

Supramolecular features

Synthesis and crystallization

Refinement

Funding information