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Maaninen T Tuononen HM Schatte G Suontamo R Valkonen J Laitinen R Chivers T 《Inorganic chemistry》2004,43(6):2097-2104
The thermal decomposition of Se(NAd)(2) (Ad = 1-adamantyl) in THF was monitored by (77)Se NMR and shown to give the novel cyclic selenium imide Se(3)(NAd)(2) as one of the products. An X-ray structural determination showed that Se(3)(NAd)(2) is a puckered five-membered ring with d(Se-Se) = 2.404(1) A and |d(Se-N)| = 1.873(4) A. On the basis of (77)Se NMR data, other decomposition products include the six-membered ring Se(3)(NAd)(3), and the four-membered rings AdNSe(micro-NAd)(2)SeO and OSe(micro-NAd)(2)SeO. The energies for the cyclodimerization of E(NR)(2) and RNEO (E = S, Se; R = H, Me, (t)Bu, SiMe(3)), and the cycloaddition reactions of RNSeO with E(NR)(2), RNSO(2) with Se(NR)(2), and S(NR)(2) with Se(NR)(2) have been calculated at MP2, CCSD, and CCSD(T) levels of theory using the cc-pVDZ basis sets and B3PW91/6-31G* optimized geometries. Sulfur(IV) and selenium(IV) diimide monomers are predicted to be stable, the sole exception being Se(NSiMe(3))(2) that shows a tendency toward cyclodimerization. The cyclodimerization energy for RNSeO and the cycloaddition reaction energies of RNSeO with Se(NR)(2) as well as that of RNSO(2) with Se(NR)(2) are negative, consistent with the observed formation of OSe(micro-N(t)Bu)(2)SeO, OSe(micro-N(t)Bu)(2)SeN(t)Bu, and O(2)S(micro-N(t)Bu)(2)SeN(t)Bu, respectively. Cycloaddition is unlikely when one of the reactants is a sulfur(IV) diimide. 相似文献
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Eight- and 16-membered cyanuric-sulfanuric ring systems of the type Ar2C2N4S2(O)2Ar'2 (3a, Ar = 4-BrC6H4, Ar' = Ph; 3b, Ar = 4-CF3C6H4, Ar' = Ph; 3c, Ar = 4-CF3C6H4, Ar' = 4-CH3C6H4) and Ar4C4N8S4(O)4Ar'4 (4b, Ar = 4-CF3C6H4, Ar' = Ph; 4c, Ar = 4-CH3C6H4, Ar' = Ph; 4d, Ar = 4-CF3C6H4, Ar' = 4-CH3C6H4), respectively, were prepared in good yields by the reaction of the corresponding sulfur(IV) systems with m-chloroperbenzoic acid. The X-ray structures of 3b, 3c.C7H14, 4b.CH2Cl2, 4c, and the S(IV) system Ar4C4N8S4Ar'4 (2c, Ar = 4-CH3C6H4, Ar' = Ph) were determined. Upon oxidation the two oxygen atoms in 3b and 3c.C7H14 adopt endo positions leading to a twist boat conformation for the C2N4S2 ring. The 16-membered C4N8S4 rings in 4b and 4c retain a cradle conformation upon oxidation. The S-N bond distances are ca. 0.06 A shorter in all the S(VI) systems compared to those in the corresponding S(IV) rings. The thermolysis of 3b at ca. 220 degrees C occurs primarily via loss of a sulfanuric group, NS(O)Ph, to give the six-membered ring (4-CF3C6H4)2C2N3S(O)Ph (6). The structure of 6 was confirmed by X-ray crystallography. Crystal data: 2c, triclinic, space group P1 with a = 13.917(2) A, b = 15.610(4) A, c = 13.491(3) A, alpha = 95.77(2) degrees, beta = 114.82(1) degrees, gamma = 76.21(2) degrees, V = 2583(1) A3, and Z = 2; 3b, monoclinic, space group P2(1)/a with a = 7.316(2) A, b = 29.508(5) A, c = 12.910(2) A, beta = 101.30(2) degrees, V = 2733(1) A3, and Z = 4; 3c.C7H14, triclinic, space group P1 with a = 12.849(4) A, b = 12.863(4) A, c = 12.610(7) A, alpha = 110.61(3) degrees, beta = 105.77(3) degrees, gamma = 62.77(2) degrees, V = 1719(1) A3, and Z = 2; 4b.CH2Cl2, triclinic, space group P1 with a = 12.647(3) A, b = 19.137(3) A, c = 12.550(2) A, alpha = 105.765(11) degrees, beta = 93.610(15) degrees, gamma = 88.877(16) degrees, V = 2917.2(9) A3, and Z = 2; 4c, orthorhombic, space group Pba2 with a = 22.657(2) A, b = 10.570(2) A, c = 10.664(3) A, alpha = beta = gamma = 90 degrees, V = 2554(1) A3, and Z = 2; 6, triclinic, space group P1 with a = 7.4667(8) A, b = 11.3406(12) A, c = 13.5470(14) A, alpha = 108.000(2) degrees, beta = 105.796(2) degrees, gamma = 94.300(2) degrees, V = 1033.8(2) A3, and Z = 2. 相似文献
45.
Tristram Chivers 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):679-687
Abstract Several aspects of recent developments in the chemistry of multiply bonded selenium and tellurium compounds are surveyed in this article. These include (a) tellurium(IV)-nitrogen compounds, (b) complexes with two (or more) terminal Group 14–Group 16 linkages, and (c) a new approach to previously inaccessible ligands containing Group 15–Group 16 functionalities. 相似文献
46.
T. Chivers S. W. Liblong J. F. Richardson 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4)
Abstract The reactions of (Me3SiNR)PPh2 (NSiMe3) (R=H, SiMe3) with (NSCl)3 or SxCl2 (x=1, 2) provide improved preparative routes to mixed phosphazene-thia-zene ring systems, e.g. (Ph2PN) (SN)2, 1,3- and 1,5-(Ph2PN)2(SN)2. The interaction of these heterocycles with protonic and Lewis acids, e.g. HBF4, BCl3, MeSO3CF3, has been investigated in order to determine the site of attack and the effect of adduct formation on the molecular and electronic structures of these ring systems. These reactions have been monitored by UV-visible and 31P NMR spectroscopies and the structures of crystalline adducts have been determined by X-ray crystallography. For example, the interaction of 1,3-(Ph2PN)2(SN)2 with MeSO3CF3 gives a product in which the methyl group is attached to a nitrogen atom between phosphorus and sulfur. The resulting structural distortion in this and related adducts will be analyzed in the context of the electronic structures of mixed phosphazene-thiazene systems and their adducts with Lewis acids. 相似文献
47.
Semigroup Forum - Let $$f_1(n), \ldots , f_k(n)$$ be polynomial functions of n. For fixed $$n\in \mathbb {N}$$ , let $$S_n\subseteq \mathbb {N}$$ be the numerical semigroup generated by... 相似文献
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Garje SS Eisler DJ Ritch JS Afzaal M O'Brien P Chivers T 《Journal of the American Chemical Society》2006,128(10):3120-3121
Aerosol-assisted chemical vapor deposition (AACVD) of Sb[(TePiPr2)2N]3 results in pure hexagonal Sb2Te3 nanoplates between 375 and 475 degrees C on glass substrates, with a potential for enhanced thermoelectric properties for novel nanodevices. 相似文献
50.
Tristram Chivers 《Journal of fluorine chemistry》2002,115(1):1-8
The pentafluorophenylboron halides C6F5BX2 (X=Cl, F) and (C6F5)2BCl were first reported in the early 1960s. After a period of inactivity these perfluoroarylboron derivatives have been employed for the synthesis of a variety of important compounds, including monomeric iminoboranes, a highly electrophilic hydroboration reagent, strong Lewis acids (with one or two acceptor sites) that activate alkyl metallocene polymerization catalysts, and the first organoxenon(IV) compounds. These recent developments provide a cogent example of the time lag that often occurs between discovery and applications in fundamental research. 相似文献