Song Ping Huang

Coordination chemistry of heavy polychalcogenide ligands

Abstract The coordination complexes of polychalcogenide ligands with metal ions are reviewed. In the past two decades, the chemistry of metal polysulfides has been extensively studied, while a great deal of attention is currently being paid to metal polyselenides and polytellurides. Compounds of metal heavy polychaleogenides are primarily of interest regarding their structure and reactivity, but they also provide potential for being used as soluble precursors to some technologically relevant metal chalcogenides. This article focuses on coordination compounds of metal polyselenides and polytellurides, both homoleptic species and organometallic complexes with heavy polychalcogenide co-ligands, from the synthetic and structural point of view. After giving a comprehensive survey of the compounds known to date according to the periodic table, some applications and an outlook in this research area are discussed.

Synthesis and properties of the homo- and heteropolychalcogenide [A(Q5)2]2− family (ATe, QS, Se; ASe, QSe). Crystal structures of (Ph4P)2[Te(S5)2] and β-(Ph4P)2[Se(Se5)2]

Abstract The reaction of Na2Te4 with K2S5 in dimethylformamide in the presence of Ph4PCl gave (Ph4P)2[Te(S5)2] (1). Under the same conditions, the reaction of elemental tellurium with Na2Se5 afforded (Ph4P)2[Te(Se5)2] (II), while β-(Ph4P)2[Se(Se5)2] (III) was made by reacting Na2Se5 with I2. The X-ray powder diffraction studies showed that I, II and III are isostructural. The structures of I and III were determined by X-ray single crystal analysis. The [A(Q5)2]2− anions in the two compounds contain either a square-planar Te2+ in I or Se2+ centre in III, which is situated on an inversion centre and chelated by two S52− or Se52− ligands. The bond distances between the central A2+ and its surrounding four Q atoms are TeS(1) = 2.699(2) A and TeS(5) = 2.752(2) A, or SeSe(1) = 2.653(2) A and SeSe(5) = 2.693(2) A. SS bond distances [av. SS = 2.075(12) A] or SeSe bond distances [av. SeSe = 2.314(13) A] are normal and in good agreement with those found in other polysulphide or polyselenide compounds. The conformation of each AQ5 ring in I and III is very close to a “chair”. The solution UV—vis spectra of DMF solutions for all three compounds are reported.

Synthesis, structure and 77Se/119Sn NMR spectroscopy of the new polyselenide, tris(tetraselenido)stannate(IV), [Sn(Se4)3]2−

Abstract The reaction of sodium pentaselenide with SnCl4 or SnCl2·2H2O in dimethylformamide (DMF), in a 3:1 ratio, forms the new soluble anion [Sn(Se4)3]2− in high (>79%) yields. The compound (Ph4P)2[Sn(Se4)3] (I) crystallizes in the monoclinic space group P21/c with unit cell dimensions, a = 13.320(2), b = 11.678(3), c = 34.817(9) A, β = 98.85(2)° and V = 4535 A3. A single-crystal X-ray diffraction study of I shows that three chelating Se42− ligands provide an octahedral coordination about the central Sn4+ atom. The crystal structure was solved and refined with conventional techniques to R = 6.0% and Rw = 7.0%. The average SnSe distance is 2.709(13) A, while the average SeSe bond distance is 2.324(12) A. The IR spectrum of I (CsI pellet) shows two sets of absorptions at 273, 256 cm−1 and 181, 173 cm−1, respectively, assigned tentatively to ν(SeSe) and ν(SnSe) vibrations. The 119Sn NMR spectrum of I in DMF, shows a single resonance at − 723 ppm (vs Me4Sn). The 77Se NMR spectrum of I in DMF, shows two resonances at 618 and 459 ppm. Thermal decomposition of I results in formation of SnSe2 at 510°C. Further heating, above 600°C, results in SnSe.

Application of the hydro(solvo)thermal technique to the synthesis of metal carbonyl chalcogenide clusters Part 3. Synthesis, structural characterization, and spectroscopic studies of the clusters [{M(CO)4}n(MS4)]2− (M Mo, W; n=1, 2)☆

The methanothermal reactions of M(CO)6 (M  Mo, W) with Na2S2 gave a series of homonuclear clusters [{M(CO)4}n(MS4)]2− (M=Mo, W; n=1, 2), i.e. (Ph4P)2[(CO)4Mo(MoS4)] (I), (Ph4P)2[(CO)4W(WS4)] (II), (Ph4P)2[(CO)4Mo(MoS4)Mo(CO)4] (III) and (Ph4P)2[(CO)4W(WS4)W(CO)4] (IV). The two dimers, I and II, as well as the two trimers, III and IV, are isostructural to each other, respectively. All compounds crystallize in the triclinic space group P1 with Z=2. The cell dimensions are: a=12.393(8), b=19.303(9), c=11.909(6) A, α=102.39(5), β=111.54(5), γ=73.61(5)°, V=2522(3) A3 at T=23 °C for I; a=12.390(3), b=19.314(4), c=11.866(2) A, α=102.66(2), β=111.49(1), γ=73.40(2)°, V=2511(1) A3 at T=23 °C for II; a=11.416(3), b=22.524(4), c=10.815(4) A, α=91.03(2), β=100.57(3), γ=88.96(2)°, V=2733(1) A3 at T=−100 °C for III, a=11.498(1), b=22.600(4), c=10.864(3) A, α=90.92(2), β=100.85(1), γ=88.58(1)°, V=2771(2) A3 at T=23 °C for IV. The dimers are each formed by the coordination of the tetrathiometalate as a bidentate chelating ligand to an M(CO)4 fragment while addition of another M(CO)4 fragment to the dimers results in the trimers. All compounds contain both tetrahedral and octahedral metal centers with the formal 6+ and 0 oxidation states, respectively.

Gold Inorganic Rings Based on Polychalcogenide Chains

Abstract The reaction of AuCN with Sex 2- and Tex 2- in dimethylformamide in the presence of organic cations forms complexes with ring structures such as (Ph4P)2[Au2Se5] (I), (Ph4P)2[Au2Se6] (II), (Ph3P N P Ph3)2 - K2[Au4Te4]·2DMF (III). The reaction of AuCl3 with Te2- yielded (Ph4P)2[Au2(Te2)2] (IV). (I) crystallizes in the triclinic space group P-1 with a=10.381(4) A, b=11.002(5) A, c=21.181(9) A, α = 75.50(4)°, β = 74.74(3)°, γ=81.40(4)°, V=2250 A3 (-93 °C). (II) crystallizes in the monoclinic space group C2/c with a=28.409(7) A, b=10.97(1) A, c=19.762(5) A, β=130.49(1)°, V=4680 A3 (-93 °C). (III) crystallizes in the orthorhombic space group Pbcn with a=29.90(2)A, b=17.39(2)A, c=17.707(8)A, V=9206A3 (23 °C). (IV) crystallizes in the triclinic space group P-1 with a=10.526(3)A, b=11.237(2)A, b=11.237(2)A, α=103.03(2)°, β=106.95(3)°, γ=81.66(2)°, V=1148 A3 (-95 °C). Single-crystal X-ray diffraction studies of (I) and (11) show that both compounds possess the same structural feature. Two linearly-coordina...