Interference from elemental sulphur in the determination of organotins by gas chromatography with flame photometric detection

Elemental sulphur, a common constituent of marine sediments, has been shown to give dialkyl sulphides with the Grignard reagents commonly used to derivatize alkyltin species before their determination by gas chromatography with flame photometric detection (GC–FPD). Further, it has been demonstrated that even with the red filter for 610 nm (normally used for organotin compounds) fitted to the detector, sulphur compounds do give rise to an emission signal, which may be mistaken for tin emission from a pentylated or propylated alkyltin compound, as the respective retention times are in some cases quite close. © 1997 by John Wiley & Sons, Ltd.     

The x-ray structure determinations and semiempirical PM3 calculations of two chloro(piperidyl)cyclotri(phosphazenes)

Single crystals of 2,4,6,6-tetrachloro-2,4-bis(piperid-yl)cyclotri(phosphazene) ( 1a ) and of 2,4,6-trichloro-2,4,6-tris(piperidyl)cyclotri(phosphazene) ( 2a ) were grown from petroleum ether solution. The structures of both compounds were determined by single-crystal X-ray diffraction analyses. Compound 1a crystallizes in the monoclinic space group P 2₁/n with Z = 4 and unit cell dimensions a = 9.3994(4), b = 19.204(3), c = 11.5664(4) Å, and β = 108.718(4)°. Compound 2a crystallizes in the triclinic space group P 1 with Z = 4 and unit cell dimensions a = 12.8289(2), b = 13.8856(2), c = 14.63810(10) Å, and α = 100.7621(5), β = 91.0094(2), γ = 113.9757(6)°. The experimentally obtained structural parameters for the covalent molecules 1a and 2a compare well with those calculated at the semiempirical PM3 level of theory. These results give credence to the PM3 calculated structures of 2,4,6,6-tetraazido-2,4-bis(piperidyl)cy-clotri(phosphazene) ( 1b ) and 2,4,6-triazido-2,4,6-tris(piperidyl)cyclotri(phosphazene) ( 2b ) for which presently there are no experimental data available.

1 Non-SI units employed: 1 kcal≈︁4.184 kJ, 1 Å = 10⁻¹⁰ m (since these units are still used in computational chemistry, we employed them throughout this article).

© 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 267–271, 1997.     

Magnesium iodide–4,4′‐bipyridine–water (1/3/4) and strontium iodide–4,4′‐bipyridine–propan‐1‐ol (1/2.5/2)

Both of the title compounds, catena‐poly­[[[tetra­aqua­magnesium(I)]‐μ‐4,4′‐bi­pyridine‐κ²N:N′] diiodide bis(4,4′‐bi­pyridine) solvate], {[Mg(C₁₀H₈N₂)(H₂O)₄]I₂·2C₁₀H₈N₂}_n, (I), and catena‐poly­[[[μ‐4,4′‐bi­pyridine‐bis­[di­iodo­bis­(propan‐1‐ol)­strontium(I)]]‐di‐μ‐4,4′‐bi­pyridine‐κ⁴N:N′] bis(4,4′‐bi­pyri­dine) solvate], {[Sr₂I₄(C₁₀H₈N₂)₃(C₃H₈O)₄]·2C₁₀H₈N₂}_n, (II), are one‐dimensional polymers which are single‐ and double‐stranded, respectively, the metal atoms being linked by the 4,4′‐bi­pyridine moieties. The Mg complex, (I), is [cis‐{(H₂O)₄Mg(N‐4,4′‐bi­pyridine‐N′)_(2/2)}]_(∞|∞)I₂·4,4′‐bi­pyridine and Mg has a six‐coordinate quasi‐octahedral coordination environment. The Sr complex, (II), is isomorphous with its previously defined Ba counterpart [Kepert, Waters & White (1996). Aust. J. Chem. 49 , 117–135], being [(propan‐1‐ol)₂I₂Sr(N‐4,4′‐bi­pyridine‐N′)_(3/2)]_(∞|∞)·4,4′‐bi­pyridine, with the I atoms trans‐axial in a seven‐coordinate pentagonal–bipyramidal Sr environment.     

Di‐μ‐benzoato‐bis­[di­carbonyl­(pyri­dine)­ruthenium(I)] (new polymorph) and di‐μ‐tri­fluoro­acetato‐bis­[di­carbonyl­(pyridine)­ruthenium(I)]

The syntheses and crystal structure determinations of a pair of `sawhorse' dimers are reported, viz. [Ru₂(C₆H₅CO₂)₂(C₅H₅N)₂(CO)₄] [a new polymorph, cf. Kepert, Deacon, Spiccia, Fallon, Skelton & White (2000). J. Chem. Soc. Dalton Trans. pp. 2867–2874] and [Ru₂(CF₃CO₂)₂(C₅H₅N)₂(CO)₄]. The Ru⋯Ru distances are 2.6724 (2) and 2.7122 (5) Å, respectively.     

Structural reliability of building blocks in coordination framework design

The use of the building‐block methodology in designing coordination framework materials are discussed, with particular reference to the structural reliability of a given building block. The term structural reliability is defined for a given metal containing moiety as the degree to which that building block reproducibly adopts a given, predicted, coordination arrangement when reacted with a series of chemically related bridging ligands. This terminology is discussed with respect to a range of coordination frameworks constructed using Cd(NO₃)₂ as a building‐block, which is demonstrated to be structurally unreliable. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:574–577, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10092