Dietrich K. Breitinger

C-Mercurierung von tertiären Enaminen

Der bisher einzige Fall einer C-Mercurierung von Enaminen wurde bei der Umsetzung von 1-Pyrrolidino-cyclopenten-(1) mit Quecksilber(II)-chlorid und-bromid in Ather gefunden. Unter den gleichen Bedingungen gelang die C-Mercurierung von 1-Dicyclohexylamino-2-methyl-propen-(1) nicht.

The Crystal Structure of Diammonium trans-Tetraammindisulfitonithenate(II)Tetrahydrate,trans-(NH4)2[Ru(SO3)2(NH3)4]·4H2O,and the Tuning of the trans-Influence of the Sulfite Ligand

Abstract trans-(NH4)2[Ru(SO3)2(NH3)4]·4H2O(1) (monoclinic, P21/n; a = 629.8(3), b = 1000.6(2), c = 1345.7(5) pm, β = 112.25(4)°, Z = 2; R = 0.021; Rw = 0.017) is obtained as pale greenish-yellow crystals by reaction of trans-[Ru(SO3H)2(NH3)4] (2) with aqueous ammonia, and crystallization at +5 °C. The compound, when isolated, is stable at room temperature for only a few days even under inert gas, but persists under the mother liquor. In the centrosymmetric anion trans-[Ru(SO3)2(NH3)4]2- the bonds Ru-S = 230.5(1) pm are significantly longer than in the neutral complex 2 (227.6(1) pm), whereas the Ru-N bonds are the same in both complexes within experimental error (averages 214.1 and 214.0 pm). Hence, the mutual trans-influence of the sulfite ligands is weakened on protonation; the bonding of the co-ligands in cis-position is not affected. The internal structure of the sulfite ligand in 1 with long S-O bonds (average 151.2(5) pm) and small angles O-S-O (average 106.1(6)°) and the weakened Ru-S bond are a good match. The structure of 1 is held together by a complex network of hydrogen bonds, in which all potential hydrogen-bond donors (OH2, NH4+, NH3) and acceptors (H2O ,SO3) are involved. The structural findings are reflected in the vibrational spectra.

Metallomethane, VI [1]. Kristallstruktur von Tetrakis(chloroquecksilber)methan-Dimethylsulfoxid C(HgCl)4 · (CH3)2SO / Metallomethanes, VI [1]. Crystal Structure of Tetrakis(chloromercuri)methane-Dimethylsulfoxide C(HgCl)4 · (CH3)2SO

The tetrakis (halomercuri) methane dimethylsulfoxide solvates C(HgX)4 · DMSO (X = Cl and Br) have been prepared. - The crystal structure of the chloro compound C(HgCl)4 · DMSO has been determined (R = 0.0611 and Rw = 0.0562). The compound crystallizes in space-group P21/n with a = 1854(1) pm, b = 727.3(5) pm, c = 1049.1(6) pm, β = 94.82(3)°, Z = 4; dc = 4.873 g·cm-3, d0 = 4.51 g-cm-3. - The C(HgCl)4 molecules have C-Hg bond lengths in the range 201.4(26) to 209.9(27) pm (average 207.0 pm), and Hg-Cl bonds between 231.4(9) and 234.2(9) pm (average 233.2 pm). The bond angles Hg-C-Hg vary from 107.3(3) to 111.7(4)° (average 109.5°), and the angles C-Hg-Cl are found within the limits 172.2(24) and 178.3(25)° (mean 174.3°). DMSO molecules (S-O bond 148.6(23)pm) are coordinated via oxygen to two Hg atoms of one C(HgCl)4 molecule and to one Hg atom of a neighbouring C(HgCl)4 molecule forming two bifurcated bridges in a dimer [C(HgCl)4 · DMSO]2; two strong Cl→···Hg and two weak S→···Hg interactions also contribute to this pair formation. The dimeric units are arranged to layers in the planes (100) and (200), such that each C(HgCl)4 molecule has six C(HgCl)4 and two DMSO molecules as neighbours; with two C(HgCl)4 molecules from each adjacent layer, each C(HgCl)4 molecule achieves a total coordination number of ten. Depending on the van der Waals radius assumed for mercury a packing coefficient 0.640 ≤ k ≤ 0.691 is obtained. - Cryoscopy and vibrational spectrometry suggest monomeric, unperturbed tetrahedral C(HgX)4 molecules in DMSO solutions.

Tetraquecksilbermethane, II [1]Tetrakis(halogenoquecksilber)-methane C(HgX)4 (X = F, Cl, Br und I): Synthesen und Schwingungsspektren / Tetramercurimethanes, II [1]Tetrakis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br und I): Syntheses and Vibrational Spectra

Abstract The complete series of tetrakis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br and I) was prepared by metathesis of tetrakis(acetoxymercuri)methane and aqueous hydrofluoric acid and solutions of halides (Cl-, Br-, and I-), respectively. All compounds are insoluble in most common solvents, but partly soluble in dimethylsulfoxide. Complete vibrational spectra indicate more or less ideally tetrahedral molecules C(HgX)4 in all cases. The originally triply degenerate valence vibrations of the CHg4 entities and the force constants for the C-Hg bonds show distinct correlations with the electronegativities of the halides X. On the other hand the totally symmetrical valence vibrations of CHg4 were found to be highly sensitive to variations in X, mainly due to coupling with the valence vibrations of the Hg-X-groups of the same symmetry species. Some analogies in the vibrational behaviour of the CHg4 fragments and of the isosteric NHg4 core in tetramercurioammonium complexes were observed and discussed.

Zinc and Its Compounds

Substance Hazard Comment Zinc metal (granulated or sheets of metal) LOW HAZARD Pure zinc does not react readily with dilute acids, without a catalyst [usually copper(II) sulfate]. Iron or steel is often coated with zinc (galvanised) to protect it from rusting. Zinc metal (powder or dust) FLAM. ENVIR DANGER: in contact with water releases flammable gases which ignite spontaneously; catches fire spontaneously if exposed to air; toxic to aquatic life with long-lasting effects. Reacts violently with iodine, sulfur and copper(II) oxide. Most school samples have a surface coating of zinc oxide, making reactions unpredictable. Zinc oxide or carbonate LOW HAZARD The zinc oxide fumes (‘philosopher’s wool’) formed when zinc dust burns in air are regarded as hazardous dust. Zinc salts Solid or concentrated solutions Sulfate(VI) if 1.5 M or more Chloride & bromide if 1 M or more CORR. HARM.

The Crystal Structure of Lithium fac-Triaquatrisulfitorhodate(III)hydroxide, Li4[Rh(S03)3(OH2)3](OH)

fac-Li4[Rh(SO3)3(OH2)3](OH) crystallizes in the rhombohedral space group R3-C34, Z = 1, in trigonal setting a = 807.7(2), c = 1339.0(3) pm, V = 756.6(2)· 106 pm3, Z = 3. Rh is octahedrally coordinated by three facial S-bonded sulfite groups with Rh—S = 222.6(1) pm and three aqua ligands with Rh—O bonds Rh—O = 217.5(3) pm, elongated by a trans-influence. The average S—O bond length is 148.0(3) pm. All hydrogen atoms have been located. The OH- ion is coordinated exclusively to Li+. The anions are held together by Li+ cations in octahedral environment and by hydrogen bonds of medium strength. Alternatively, the structure can be considered to be built of packages of two oxygen nets and a metal layer, stacked in a sequence similar to that in the CdCl2-structure.

trans-Tetraamminebis(hydrogensulfito)ruthenium(II), trans-[Ru(SO3H)2(NH3)4], a Structure with an Unexpected Rod Packing

trans-[Ru(SO3H)2(NH3)4], monoclinic, space group P21/n, Z =2, a = 619.4(3), b = 701.8(3), c = 1068.6(6) pm, β = 96.32(3)°. In the centrosymmetric octahedral complex the two independent Ru–N bonds are equal within experimental error (average Ru–N 214.0 pm). The rather short Ru–S bonds (227.6 pm) indicate a very weak trans-influence of the – SO3H ligand. Caused by the protonation, one of the S–O bonds in the –SO3H ligand is long (161.4 pm), the other two are short (mean 148.0 pm). The complex units are linked by pairs of O-H ··· O hydrogen bonds (268.9 pm) to form rods parallel b (symmetry (b) · T), which in turn are held together by N–H ··· O bonds in a pseudo-hexagonal array. A packing coefficient of 0.76 is estimated.

Metallomethane, XI [1]. Einfache Darstellung von Tetrakis(halogenoquecksilber)methanen C(HgX)4 (X = F, Cl, Br und I) / Metallomethanes, XI [1]. Simple Preparation of Tetrakis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br and I)

A simple procedure for the preparation of tetra- kis(halomercuri)methanes C(HgX)4 (X = F, Cl, Br and I) from Hofmann’s base (“oxymercarbide”) and aqueous hydrohalic acids is described. Under the reaction conditions used, degradation of the CHg4 moieties present in Hofmann’s base also occurs, increasing in the series HF ≈ HC1 < HBr < HI.

Metallomethane, IV [1] Molekül-und Kristallstruktur von Bis(chloroquecksilber)metlian CH2(HgCl)2 / Metallomethanes, IV [1] Molecular and Crystal Structure of Bis(chloromercuri)methane CH2(HgCl)2

The X-ray structure analysis of bis(chloromercuri)methane CH2(HgCl)2 has been performed. CH2(HgCl)2 crystallizes in Prnma with a = 713.7(4) pm, b - 643.6(4) pm, c = 1221.7(8) pm, Z = 4; the isotypic CH2(HgBr)2 has a = 731.1(3) pm, b = 668.6(1) pm, c - 1260.1(4) pm. The CH2(HgCl)2 molecules (site symmetry m) contain asymmetric CHg2 entities with bond lengths R(C-Hg(l)) = 203.9(17) pm and R(C-Hg(2)) = 212.2(18) pm, respectively, whereas the two independent Hg-Cl bonds are almost the same (average (Hg-Cl) = 233.3(5) pm). The bond angles Hg-C-Hg (111.6(3)°) and C-Hg-Cl (average 177.8(5)°) fall into the expected range. The molecules are held together by two independent systems of short van der Waals contacts Cl →···Hg forming zig-zag chains along the 6-axis, and a wide variety of van der Waals interactions Cl →···Hg in planes parallel to (010). The arrangements in these planes produce maximum density molecular layers with coordination number six; including the molecules of two adjacent layers each molecule reaches a total coordination number of fourteen. Depending on the van der Waals radius assumed for mercury a packing coefficient 0.663 ≤ k ≤ 0.733 comparable to that of close-packing of spheres results.

Über Tetrachlorothallate(III) und -indate(III) mit Scheelit-Struktur / Tetrachlorothallates(III) and -indates(III) of Scheelite Type Structure

Abstract Tetrachlorothallates MTlCl4 (M=K, Rb and NH4) crystallizing in the tetragonal CaWO4 type were obtained by crystallization from highly concentrated aqueous TlCl3 solutions containing small amounts of MCI. The structural parameters of NH4TlCl4 were determined from single-crystal data. The indates MInCL4 (M=K, Rb and NH4) are isotypic. The vibrational spectra of the tetrachlorothallates were discussed.