Crystal Structure ofN,N-Dimethylthioformamide Solvates of the Divalent Group 12 Ions with Linear Coordination Geometry for Mercury(II), Tetrahedral for Zinc(II), and Octahedral for Cadmium(II)

Abstract

The crystalline solvates of the divalent group 12 metal ions with the soft sulfur donor N,N-dimethylthioformamide display an unusual variation in coordination number and geometry with two, four, and six ligands attached to the mercury(II), zinc(II), and cadmium(II), ions, respectively. Bis(N,N-dimethylthioformamide)mercury(II) perchlorate precipitates from acetonitrile solution when adding less than 2 equiv of N,N-dimethylthioformamide, while the zinc and cadmium solvates crystallize from saturated N,N-dimethylthioformamide solutions. The disolvate [Hg(SCHN(CH(3))(2))(2)](ClO(4))(2) crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 6.208(1) Å, b = 15.239(7) Å, c = 8.681(2) Å, beta = 99.30(3) degrees, and Z = 2. Centrosymmetric mercury(II) complexes with strong collinear bonds to two N,N-dimethylthioformamide molecules, Hg-S 2.350(2) Å, are joined by double bridges of perchlorate ions in chains along the a-axis by four weak interactions between the mercury and the perchlorate oxygen atoms, mean Hg-O distance 2.84 Å. Tetrakis(N,N-dimethylthioformamide)zinc trifluoromethanesulfonate, [Zn(SCHN(CH(3))(2))(4)](CF(3)SO(3))(2), crystallizes in the triclinic space group P&onemacr; (No. 2) with a = 10.487(3) Å, b = 12.910(3) Å, c = 13.489(5) Å, alpha = 68.800(4) degrees, beta = 69.260(4) degrees, gamma = 74.06(1) degrees, and Z = 2, with the zinc ions tetrahedrally surrounded by four N,N-dimethylthioformamide ligands, mean Zn-S distance 2.34 Å. Also the cadmium solvate of corresponding composition, [Cd(SCHN(CH(3))(2))(4)(CF(3)SO(3))(2)], crystallizes in the space group P&onemacr;, with a = 8.670(1) Å, b = 9.529(1) Å, c = 10.685(1) Å, alpha = 75.20(1) degrees, beta = 66.97(1) degrees, gamma = 65.31(1) degrees, and Z = 1, although the structure comprises centrosymmetric tetrakis(N,N-dimethylthioformamide)bis(trifluoromethanesulfonato)cadmium(II) complexes in which four Cd-S bonds (mean 2.65 Å) and two weaker Cd-O bonds at 2.470(2) Å to the trifluoromethanesulfonate ions give rise to a pseudo-octahedral coordination around the cadmium ion. When using perchlorate instead as counterion, hexakis(N,N-dimethylthioformamide)cadmium perchlorate, [Cd(SCHN(CH(3))(2))(6)](ClO(4))(2), crystallizes in the space group P2(1)/n with a = 12.757(1) Å, b = 7.4681(6) Å, c = 19.732(2) Å, beta = 96.31(1) degrees, and Z = 2. The mean Cd-S bond distance increases to 2.715 Å in the fully solvated cadmium ion with almost regular octahedral coordination geometry to its six centrosymmetrically related ligands. The effect of the weak internal hydrogen bonding occuring between the hydrogen atom of a -CHS group and the sulfur atom of neighboring N,N-dimethylthioformamide ligands is discussed.

Structural, Spectroscopic, and Reactivity Properties of N2S2(thioether)‐O(amide)‐Ligated HgII Complexes: The First Examples of HgII‐Mediated Amide Cleavage

“…[10][11][15][16] Thus, the Hg(1)-S(2) interaction is consistent with strong coordination to the Hg II center, whereas the Hg (1) [3] Perchlorate coordination to Hg II has been observed in several previously reported complexes. [4,[17][18][19][20][21] In these, the Hg II -O(perchlorate) bond lengths generally range from 2.66-2.95 Å. Notably, one of these reported structures has Hg II -S(thioether) bonding as well as a weakly coordinated perchlorate (Hg-O, 3.08 Å) in a sixth coordination position.…”

An EXAFS Spectroscopic, Large‐Angle X‐Ray Scattering, and Crystallographic Study of Hexahydrated, Dimethyl Sulfoxide and Pyridine 1‐Oxide Hexasolvated Mercury(II) Ions

“…[9,10] Di-and tridentate sulfur-donor ligands are required to form six-coordinated mercury(II) complexes. [11][12][13] The destabilization of regular six-coordinated mercury(II) complexes, including small monodentate ligands, such as ammonia, is often attributed to a contribution of the mercury(II) 5d z 2 atomic orbital to the bonding molecular orbitals by vibronic coupling of pseudo-degenerate electronic states in a socalled pseudo-Jahn-Teller effect (PJTE).…”

“…No evidence of disordering or large vibrational movements was found for the perchlorate ions in spite of the absence of hydrogen bonds. The perchlorate ion is located on the three-fold axis, with one Cl À O bond along the axis, 1.4366 (13) , and three equivalent symmetry related Cl À O bonds of 1.4447 (9) . The average Cl À O distance of 1.442 does not vary significantly from the values found in weakly hydrogen-bonded perchlorates, 1.41-1.44 , as observed for a large number of compounds.…”

Selective removal of mercury(II) from wastewater using polythioamides

“…1). It has been reported that the complexes of Hg(II) with N-(substitutedphenyl)thiobenzamide [7] and N,N-dimethylthioformamide [8] are due to sulfur donation. In the IR spectrum of Hg(II)-sorbed PTA1, a higher frequency shift of (C-N) for the thioamide group (1539 cm −1 ) was observed (1490 cm −1 for PTA1 before the sorption), indicating the sulfur-coordination of the thioamide group and an increase in double bond character of the C-N bond in the coordination form [7,16].…”

“…It is known that Hg(II) forms a stable complex with thioamide ligand [7,8]. However, to our knowledge, only a few reports have been appeared for the polymer sorbents having thioamide group for Hg(II) [9,10].…”