Synthesis and characterization of [M(DMSO)₆][SnCl₆] complexes (M = Fe²⁺, Co²⁺, and Ni²⁺) — An old mystery solved

Abstract

The synthesis of an "unknown" Fe(II) complex originally reported in 1973 and formulated then as [Fe(DMSO)5Cl][SnCl4] was thoroughly reproduced and the compound reformulated as the novel [Fe(DMSO)6][SnCl6] double complex salt. Current elemental analysis and IR and Mössbauer spectroscopy matched the original 1973 data, and Raman spectroscopy and single crystal X-ray diffraction provided additional confirmation of our reformulation. [Fe(DMSO)6][SnCl6] (1) crystallizes in the trigonal space group R[Formula: see text] with octahedral [Fe(DMSO)6]2+ and [SnCl6]2– complex ions with an Fe—O bond length of 2.121(3) Å. The same synthesis was extended to Co(II) and Ni(II) to generate the novel [Co(DMSO)6][SnCl6] (2), which crystallizes in the triclinic space group P[Formula: see text] with a Co—O bond length of 2.093(4)–2.113(5) Å, and [Ni(DMSO)6][SnCl6] (3), which crystallized in the trigonal R[Formula: see text] space group and has a Ni—O bond length of 2.062(2) Å. The Sn—Cl bond length in all three complexes ranged from 2.421(2) to 2.448(2) Å.Key words: DMSO complexes of Fe(II), Co(II) and Ni(II), SnCl62– salts, IR, Raman and Mössbauer spectroscopy, X-ray crystal structures.

Structural Feature of a Hexa-DMSO Cobalt(II) Complex: <i>Pseudo</i>-<i>S</i>₆ Symmetry and <i>Pseudo</i>-<i>C</i>_2v Deformation

“…Although the pseudo-S6 symmetry has been observed in several derivatives, 3,5 the deformation of the present complex is the largest among the [Co(DMSO)6] 2+ complexes. [3][4][5][6] This is because a [Co(DMSO)6] 2+ cation in the present compound is perfectly surrounded by eight tetraphenylborate anions, which are attracted to the complex cation by eleven distinct CH•p interactions.…”

Crystal structure of hexakis(dimethyl sulfoxide-κO)cobalt(II) bis[trichlorido(quinoline-κN)cobaltate(II)]

“…The packing of (Comuzzi et al, 2002), while a subsequent report lists Co-O distances in the range 2.088 (2)-2.110 (2) Å , with O-Co-O (cis) angles between 85.26 (7) and 93.67 (8) (Chan et al, 2004). In [Co(Me 2-SO) 6 ][SnCl 6 ], both the cobalt and tin metal ions display an octahedral environments, with the Co-O bond lengths reported between 2.093 (4) and 2.113 (5) Å (White et al, 2007). The O-Co-O (cis) angles vary between 89.0 (2) and 90.0 (2) (White et al, 2007).…”

“…In [Co(Me 2-SO) 6 ][SnCl 6 ], both the cobalt and tin metal ions display an octahedral environments, with the Co-O bond lengths reported between 2.093 (4) and 2.113 (5) Å (White et al, 2007). The O-Co-O (cis) angles vary between 89.0 (2) and 90.0 (2) (White et al, 2007).…”

Crystal Structure of a Mononuclear Iron(III) Complex, Hexakis(dimethylsulfoxide-κ<i>O</i>)iron(III) Tris(hexafluoridophosphate)

“…3), and the disordered structure seemed to be consistent with the sulfur-inversion motion; 2,3 however, we will discuss only the main structure because the occupancy of the disordered minor unit is very small It is of interest to compare the structure of the trivalent [Fe(dmso)6] 3+ complex cation, observed in this study, with the related divalent [Fe(dmso)6] 2+ complex cation. 5 Both cations belong to the exact S6 point group. In the trivalent complex cation, the Fe(III)-O distance is 1.996(2)Å (Table 2) In the crystal structure of the trivalent [Fe(dmso)6] 3+ complex cation, the intermolecular CH•••F interactions (C•••F = ∼3.46 Å) were found to stabilize the highly symmetrical crystal structure by connecting the methyl hydrogen in the dmso moiety and the fluorine atom in the hexafluoridophosphate ion.…”

“…of reflections collected = 6538 No. of independent reflections = 1630 [R(int) = 0.0338] θ range for data collection: 2.181 to 28.533 Data/Restraints/Parameters = 1630/66/135 Goodness-of-fit on F 2 = 1.046 R indices [I > 2σ(I)]: R1 = 0.0509, wR2 = 0.1343 R indices (all data): R1 = 0.0853, wR2 = 0.1565 (Δ/σ)max = 0.000 (Δρ)max = 0.440 eÅ -3 (Δρ)min = -0.290 eÅ Measurement: Bruker Smart APEX CCD diffractometer Program system: SHELXTL Structure determination: intrinsic phasing methods (SHELXT 2014/5) Refinement: full matrix least-squares (SHELXL-2014/7) CCDC deposition number: 1856764complex cations,4,5 belonging to the exact S6 or pseudo-S6 symmetry.…”