Showing papers by "Brian W. Skelton published in 1982"
47 citations
TL;DR: The structure of the three title compounds have been determined by single-crystal X-ray diffraction methods at 295(1) K as mentioned in this paper, with a= 17.726(7), b= 8.572(3), c= 3.510(5)A, and Z= 4, the stuctural unit also being the [HgI2(py)2] molecule with similar geometry to that of (2); in particular, HgI 2.70 (1) and 2.3(4)°.
Abstract: The structures of the three title compounds have been determined by single-crystal X-ray diffraction methods at 295(1) K. For [HgCl2(py)2],(1), a redetermination, the cell is Monoclinic, space groupP21/n, with a= 17.726(7), b= 8.572(3), c= 3.910(2)A, β= 92.00(4)°, and Z= 2. The structure is a chloride-bridged polymeric lattice of HgCl4 square-planar entities [Hg–Cl 2.754(2) and 2.765(2)A] with pyridine ligands filling the trans-octahedral sites about the mercury atom [Hg–N 2.266(6)A]. For [HgBr2(py)2], (2), the cell is Orthorhombic, space group Pca21, with a= 18.023(5), b= 8.754(3), c= 8.592(3)A, and Z= 4; the basic structural unit is the [HgBr2(py)2] molecule [Hg–Br 2.478(3) and 2.483(3)A, Br–Hg–Br 141.2(1)°; Hg–N 2.38(2) and 2.39(2)A, N–Hg–N 90.7(7)°, N–Hg–Br 102.5(5)–104.3(4)°]. For [HgI2(py)2], (3), the cell is also Orthorhombic, space group Pnma, with a= 14.545(7), b= 11.396(6), c= 8.510(5)A, and Z= 4, the stuctural unit also being the [HgI2(py)2] molecule with similar geometry to that of (2); in particular, Hg–I 2.70(1) and 2.65(1)A, l–Hg–I 141.7(4)°.
35 citations
TL;DR: A high-yield synthesis of a tetrahydrofuran (thf) solution of the di-Grignard reagent (A) derived from o-bis(chloromethyl)benzene is described in this paper.
Abstract: A high-yield synthesis of a tetrahydrofuran (thf) solution of the di-Grignard reagent (A) derived from o-bis(chloromethyl)benzene is described, as well as that of an analogue obtained from 1,2-bis(chloromethyl)-4,5-dimethylbenzene. Cooling (A) to ca. –40 °C yields the colourless chloride-free Mg(CH2C6H4CH2-o)(thf) of unknown structure, whereas at ambient temperature a concentrated solution (> ca. 0.1 mol dm–3) slowly (days) deposits colourless needles of [{Mg(CH2C6H4CH2-o)(thf)2}3]. A single-crystal X-ray structure determination of the latter (R= 0.054 for 1 117 ‘observed’ reflections at 295 K) shows it to be a trimer. Crystals are orthorhombic, space group F2dd. with a= 24.706(8), b= 8.948(3), c= 44.315(9)A, and Z= 8; the trimeric unit lies on a crystallographic two-fold axis. Each of the three magnesiums is bridged to the other two by a –CH2C6H4CH2–-o ligand, the pseudo-tetrahedral co-ordination about each magnesium atom being completed by a pair of thf molecules. The utility of the di-Grignard reagent as a general metallocycle precursor is illustrated by the synthesis of [graphic omitted] (cod = cycle-octa-1,5-diene) from [Ptl2(cod)]. In contrast [PtCl2(dppe)] with [{o-C6H4(CHSiMe3)2}{Li(tmen)}2](dppe = Ph2PCH2CH2PPh2, tmen = Me2NCH2CH2NMe2) affords [Pt(dppe)2].
33 citations
TL;DR: In this paper, the authors described the distorted "piano-stool" configuration of the vinylidene ligand with the plane of the ligand bisecting the molecular symmetry plane.
Abstract: The complexes [Ru(CCR)(PMe3)L(η-C5H5)](R = Me or Ph, L = PMe3: R = Ph, L = PPh3) were obtained from reactions between [Ru(CCR)(PPh3)2(η-C5H5)] and PMe3, while [Ru(CCHR)(PMe3)2(η-C5H5)]PF6(R = H, Me, or Ph) were formed from [RuCl(PMe3)2(η-C5H5)], HCCR, and NH4PF6. Alkylation of [Ru(CCPh)(PMe3)2(η-C5H5)] with OMe3PF6 gave [Ru(CCMePh)(PMe3)2(η-C5H5)]PF6. The molecular structure of [Ru(CCHMe)(PMe3)2(η-C5H5)]PF6 is described. It has the distorted ‘piano-stool’ configuration, with the plane of the vinylidene ligand bisecting the molecular symmetry plane. For the vinylidene ligand, Ru–C 1.845(7), C–C 1.313(10)A, Ru–CC 180(2) and C–C–Me 125.1(6)°.
32 citations
TL;DR: In this paper, the crystal structures of the title compounds have been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to residuals of 0.044, 0.046, and 0.058 for 818, 1 678, 2 016 independent observations respectively.
Abstract: The crystal structures of the title compounds have been determined by single-crystal X-ray diffraction at 295 K and refined by least squares to residuals of 0.044, 0.046, 0.058 for 818, 1 678, 2 016 independent ‘observed’ reflections respectively. For all compounds, crystals are monoclinic, space group P21/c. For Hg(SeMe)2, a= 8.440(4), b= 10.732(3), c= 6.681(3)A, β= 96.14(4)°, and Z= 4. For [{HgCl(py)(SeEt)}4](py = pyridine), a= 8.044(5), b= 17.387(14), c= 15.585(21)A, β= 101.75(2)°, and Z= 2. For [{HgCl(py)0.5(SeBut)}4]a= 12.151(5), b= 16.738(7), c= 10.138(6)A, β= 90.93(4)°, and Z= 2. Crystals of Hg(SeMe)2 contain infinite one-dimensional chains along b, the pseudo-tetrahedral mercury atoms being bridged by pairs of selenium atoms; Hg–Se bond distances are in the range 2.614(2)–2.764(2)A. The complexes [{HgCl(py)(SeEt)}4] and [{HgCl(py)0.5(SeBut)}4] were obtained from pyridine solutions containing Hg(SeR)2 and HgCl2, and both contain an eight-membered ring (–Hg–SeR–)4. The former contains two independent pseudo-tetrahedrally co-ordinated mercury atoms, ‘Hg(µ-SeEt)2Cl(py)’; the latter contains two inversion related mercury atoms, ‘Hg(µ-SeBut)2Cl(py)’, and two other inversion related mercury atoms linked by a dichloro-bridge ‘Hg(µ-SeBut)2(µ-Cl)2’. The structure of [{HgCl(py)0.5(SeBut)}4] is very similar to those of [{HgCl(L)0.5(SBut)}4](L = py or 4-methylpyridine) and is isomorphous with the 4-methylpyridine analogue. Mercury–selenium bond distances are slightly shorter than expected by comparison with covalent radii of sulphur and selenium.
27 citations
TL;DR: In this paper, single-crystal X-ray structure determinations have been carried out on the diene and its Li, K, and Tl salts at 295 K.
Abstract: The alkali metal (Li, Na, K, Rb, and Cs) and thallium(I) derivatives of HC5(CO2Me)5 have been prepared and characterised; their i.r., u.v., 1H, and l3C n.m.r. spectra are reported and discussed. Single-crystal X-ray structure determinations have been carried out on the diene and its Li, K, and Tl salts at 295 K. In the solid, as in non-polar solvents, the diene has the fulvenoid configuration, with the acidic proton bridging two adjacent carbonyl groups. This configuration is preserved in univalent metal cation salts. Lithium is four-co-ordinate (from two carbonyl oxygens, the water molecule, and a carbonyl oxygen from a second anion). In the potassium salt, the metal is co-ordinated by methanol, and five carbonyl oxygens from three different anions; all carbonyl oxygens of each anion are likewise involved in co-ordination to three different metal atoms. In the thallium salt the metal has irregular five-co-ordination, with two chelating carbonyl groups from one anion and three from separate anions; all carbonyl oxygens of each anion co-ordinate to four different metal atoms.
27 citations
TL;DR: The crystal structure of (S)-(-)-6-bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-Dihydro-4H-1-benzopyran-4-one as mentioned in this paper was determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal least squares to a residual of 0.050 (810 'observed' reflections).
Abstract: The crystal structure of (S)-(-)-6-bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one [(–)-6-bromocryptostrobin] (11) has been determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal least squares to a residual of 0.050 (810 'observed' reflections). Crystals of (11) are tetragonal, P43212, a 7.849(4), c 46.83(2) A, Z 8. The crystallographic data are consistent with the S configuration previously proposed for (–)-cryptostrobin (10). The 13C n.m.r, spectra of (±)-cryptostrobin and(±)-strobopinin also lead to the structures (1) and (6), respectively. This work has enabled the structures proposed for the natural products (±)-lawinal, unonal, 7-O-methylunonal and isounonal to be revised to (8), (14), (15) and (12), respectively.
26 citations
TL;DR: In this paper, the crystal structure of [Os(NO)(PMe3)2(η-C5H5)][PF6]2 has been determined by single-crystal X-ray methods at 295 K and refined by least squares to a residual of 0.044 for 2 038 ‘observed’ reflections.
Abstract: Reaction of [MX(PR3)2(η-C5H5)](M = Ru, X = Cl; M = Os, X = Br; R = Me or Ph) with HPF6 gives the metal(IV) complexes [MH(X)(PR3)2(η-C5H5)][PF6], and with Cl2–[NH4][PF6] gives [RuCl2(PMe3)2(η-C5H5)]-[PF6]. Reaction with [NO][PF6] gives the dications [M(NO)(PR3)2(η-C5H5)]2+, which have unusually high ν(NO) frequencies (1 850–1 875 cm–1). The crystal structure of [Os(NO)(PMe3)2(η-C5H5)][PF6]2 has been determined by single-crystal X-ray methods at 295 K and refined by least squares to a residual of 0.044 for 2 038 ‘observed’ reflections. Crystals are orthorhombic, space group Pbca, with a= 21.680(6), b= 16.606(4), c= 12.772(5)A, and Z= 8. The Os–N–O system is linear, Os–N 1.75(1), N–O 1.17(2)A being indicative of the OsN+O moiety; Os–P lengths are 2.367(4) and 2.364(4)A and Os–C 2.23(2)–2.29(2)A.
20 citations
TL;DR: In this article, the α-functionalised alkyl cis-[Pt(CH2I)I(PEt3)2] with excess PEt3 yields trans-[Pd(CH 2PEt 3) I(PPh3) 2]I.
19 citations
TL;DR: In this paper, LiBun in n-hexane in the presence of Me2NCH2CH2NMe2(tmeda) or MeN (CH2 CH2NME2)2(pmdeta) results in selective lithiation of the α-carbon in a manner dependent on the nature of the associated substituents and the tertiary amine to afford novel crystalline lithium alkyls.
Abstract: Reaction of [o-C6H4(CHRR′)(CHR″R‴)](R,R′,R″,R‴H or SiMe3) With LiBun in n-hexane in the presence of Me2NCH2CH2NMe2(tmeda) or MeN (CH2CH2NMe2)2(pmdeta) results in selective lithiation of the α-carbon in a manner dependent on the nature of the associated substituents and the tertiary amine to afford novel crystalline lithium alkyls; a single-crystal X-ray structure determination of [{o-C6H4(CHSiMe3)2}{Li(tmeda)}2] shows each lithium to interact with both the α-and adjacent ring carbon atoms from opposite sides of the o-xylidene plane
15 citations
TL;DR: In this article, the molecular structure of PF6·CH2Cl2 has been determined by a single-crystal X-ray analysis and the structure was solved by heavy-atom methods at 295(1) K and refined by least-squares methods to R= 0.051 for 4 384 observed reflections.
Abstract: The complexes [Pd(η5-C5H5)L2]PF6[where L = PMe2Ph, PPh3, AsMe2Ph, AsPh3, or SbPh3 and L2=(SS)-, (RR,SS)-, (RS)-C6H4(PMePh)2-o or (SS)-, (RR,SS)-, (RS)-C6H4(AsMePh)2-o] have been prepared in high yield from the appropriate complexes [PdCl2L2] and cyclopentadiene in Me2CO in the presence of AgPFe6, or with AgNO3 followed by metathesis with NH4PF6. The brightly coloured compounds conduct as uni-univalent electrolytes in Me2CO and CH2Cl2 and have spectroscopic properties consistent with η5 co-ordination of the cyclopentadienyl moiety in solution. The molecular structure of [Pd(η5-C5H5)(SbPh3)2]PF6·CH2Cl2 has been determined by a single-crystal X-ray analysis. The crystals are monoclinic, space group P21/c with a= 12.506(6), b= 19.002(7), c= 18.575(5)A, β= 106.53(3)°, and Z= 4. The structure was solved by heavy-atom methods at 295(1) K and refined by least-squares methods to R= 0.051 for 4 384 observed reflections. The arrangement of the two antimony atoms and the centre of the cyclopentadienyl ring about the palladium atom is approximately trigonal. The co-ordinated cyclopentadienyl moiety shows no significant deviations from planarity.
TL;DR: In this article, the spirocyclic complex S n (C H S iM e 3 C 6 H 4 ︹ C H S I M e 3 − o ) 2 in which both ligands are in the meso configuration was more conveniently obtained from II and Sn(OC6H2Me-4-But2-2,6)
TL;DR: In this article, the potentially tridentate chelating agent bis(6-methylquinolin-8-yl)phenylarsine (AsN2) and quadridentate tris(6 -methylquinolithio-quinoline and dichlorophenylarsines or arsenic trichloride, respectively.
Abstract: The potentially tridentate chelating agent bis(6-methylquinolin-8-yl)phenylarsine (AsN2) and quadridentate tris(6-methylquinolin-8-yl)arsine (AsN2) have been prepared from 6-methyl-8-lithio-quinoline and dichlorophenylarsine or arsenic trichloride, respectively. Both ligands behave as bidentates in complexes of the type [PdX2(AsN2)] and [PdX2(AsN2)] (where X = Cl or I) and as tridentates in [Mo(CO)3(AsN2)] and [Mo(CO)3(AsN2)]. The crystal and molecular structures of [PdCl2(AsN2)],CH2Cl2 and [PdI2(AsN2)] have been determined by single-crystal X-ray analysis. The dichloro complex crystallizes in space group P1 (Ci1; No.2) with a 9.963(3), b 8.555(3), c 16.102(7) A; α 86.64(3), β 82.13(3), γ 85.84(3)o; U 1354.3(9) A3 and Z = 2. The structure was solved by heavy-atom methods and refined by least squares to R 0.044 for 2530 'observed' reflections with 1>3σ(I). The coordination geometry of the palladium(II) atom is pseudo-square-planar in which the potentially tridentate AsN2 is behaving as a bidentate only. There is no evidence of interaction of the remaining 6-methylquinolin-8-yl group with the metal centre, although a weak interaction between the solvent of crystallization and the metal may be present. The diiodo complex similarly crystallizes in the centrosymmetric triclinic space group P1 (Cil ; No.2) with a 13.590(5), b 10.035(2), c 9.435(2) A; α 102.68(2), β 90.10(2), γ 92.99(2)o; U 1253.5(6) A3 and Z = 2. Least- squares refinement led to a convergence with R 0.038 for 3461 'observed' reflections. The structure of this complex was similar to that of the dichloro analogue.
TL;DR: The blue material produced in the oxidation of 4-methoxy-3-t-butylphenol, formerly described as an intermediate in the formation of the dibenzo[d,f][1,3]dioxepin oxidation product, is shown to be 5,5′-dimethoxy -4,4′-di-t -butyl-2,2′-diphenoquinone as discussed by the authors.
Abstract: The blue material produced in the oxidation of 4-methoxy-3-t-butylphenol, formerly described as an intermediate in the formation of the dibenzo[d,f][1,3]dioxepin oxidation product, is shown to be 5,5′-dimethoxy-4,4′-di-t-butyl-2,2′-diphenoquinone. This quinone spontaneously condenses to a colourless trimer which, in solution in polar solvents, is shown to be in equilibrium with free radicals derived from the monomer and a dimes; that from the former regenerates the quinone. The crystal structure of the dimes has been determined as 1′-(2-hydroxy-5-methoxy-4-t-butylphenyl)-4a′,5,7′-trimethoxy-4,4′-6′-tri-t-butylspiro(cyclohexa-3,5-diene-1,9′-xanthen)-2,2′(4′aH)-dione.
TL;DR: In this paper, the structure of the barium derivative has been determined at 295 K by single-crystal X-ray diffraction methods, and refined to a residual of 0.036 for 8 173 ‘ observed ’ reflections.
Abstract: White, air-stable, and water-soluble compounds M[C5(CO2Me)5]2(M = Mg, Ca, Sr, Ba, Zn, and Cd) are obtained from HC5(CO2Me)5 and the metal carbonates or acetates, or from MCl2 and Tl[C5(CO2Me)5]; the i.r., 1H n.m.r., and mass spectra are reported and briefly discussed. The structure of the barium derivative has been determined at 295 K by single-crystal X-ray diffraction methods, and refined to a residual of 0.036 for 8 173 ‘ observed ’ reflections. Crystals are triclinic, space group P, with a= 14.499(4), b= 12.940(4), c= 10.745(2)A, α= 100.54(2), β= 100.02(2), γ= 114.23(2)°, and Z= 2. The barium atom is eight-co-ordinate with an environment made up of three pairs of chelating carboxyl-carbonyl oxygen atoms and two others [Ba–O 2.655(3)–2.932(3)A]; as in the alkali-metal derivatives, there is a tendency for adjacent carboxyl-carbonyl groups to behave as chelate functions.
TL;DR: The crystal structure of the title compound, [Cr(S2CNEt2)2(OS2C NEt2)] has been determined by single crystal X-ray diffraction methods, being refined to a residual of 0.061 for 2756 'observed' reflections as mentioned in this paper.
Abstract: The crystal structure of the title compound, [Cr(S2CNEt2)2(OS2CNEt2)] has been determined by single crystal X-ray diffraction methods, being refined to a residual of 0.061 for 2756 'observed' reflections. Crystals are monoclinic, P21/c, a 16.195(5), b 8.316(2), c 17.939(7) A, ,β 96.65(3)o, Z 4. The chromium atom is coordinated by two S,S-chelate ligands and one O,S-chelate ligand, the latter being disordered over three sites.
TL;DR: The crystal structure of [Cr{C5(CO2Me)5}3] was determined by single-crystal X-ray diffraction methods and refined to a residual of 0.066 for 632 ‘ observed ’ reflections at 295 K.
Abstract: The crystal structure of [Cr{C5(CO2Me)5}3]·ca.3.75H2O, synthesised by the reaction of chromium(II) acetate with the parent acid in methanol, was determined by single-crystal X-ray diffraction methods and refined to a residual of 0.066 for 632 ‘ observed ’ reflections at 295 K. Crystals are rhombohedral, space group R, with a = 16.545(20)A, α= 60.49(7)°, and Z = 3. The molecule lies with the chromium atom situated in a three-fold symmetry axis, chelated by the carbonyl oxygen atoms of adjacent carboxyl groups, to give a tris-chelate complex : mean Cr–O 1.93 A.
TL;DR: The crystal structures of two γ-lactones of the bicyclo[2, 2,2,2] octane series, endo-3-carboxy-exo-5- iodobicyclo-2,6-carbolactone (2; R = CO2H) and exo3-methoxycarbonyl-endo-5acetoxybicycloencyl-acetoxy bicyclone (7b), have been determined by direct methods from three-dimensional X-ray data and refined by
Abstract: The crystal structures of two γ-lactones of the bicyclo[2,2,2]octane series, endo-3-carboxy-exo-5- iodobicyclo[2,2,2]octane-2,6-carbolactone (2; R = CO2H) and exo-3-methoxycarbonyl-endo-5-acetoxybicyclo[2,2,2] octane-2,6-carbolactone (7b), have been determined by direct methods from three-dimensional X-ray data and refined by least-squares to final residuals of 0.033 (2; R = CO2H) and 0.036 (7b) for 1918 and 630 'observed' reflections respectively. Crystals for (2; R = CO2H) are monoclinic, space group P21/c with Z 8 in a cell of dimensions a 7.192(2), b 23.785(8), c 13.199(5) A, β 105.35(2)o, while (7b) crystallizes in the orthorhombic space group P212121 with Z 4 in a cell of dimensions a 13.347(7), b 11.839(7), c 8.227(11) A.
TL;DR: The crystal structure of a new hydrate phase of bis(purpurato)copper(II), CuL2·≈7.6H2O (L = purpurate, C8H4N5O6−), has been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to a residual of 0.052 for 2 124 ‘observed’ reflections as mentioned in this paper.
Abstract: The crystal structure of a new hydrate phase of bis(purpurato)copper(II), CuL2·≈7.6H2O (L = purpurate, C8H4N5O6–), has been determined by single-crystal X-ray diffraction methods at 295 K, being refined by least squares to a residual of 0.052 for 2 124 ‘observed’ reflections. Crystals are triclinic, space group P, with a= 12.187(4), b= 11.889(5), c= 10.447(3)A, α= 73.57(3), β= 83.72(3), γ= 75.09(2)°, and Z= 2. Each of the purpurate ligands is symmetrically co-ordinated to the copper atom in a tridentate manner, but in consequence of Jahn–Teller distortion, considerable differences are found between them; for one ligand Cu–N is 1.973(6) and Cu–O 2.023(7), 2.029(7)A, while for the other, Cu–N is 2.021(5) and Cu–O 2.289(5), 2.303(5)A.
TL;DR: In this paper, the structure of compound (3) was deduced from its spectroscopic properties and was confirmed by X-ray diffraction, and the structure was confirmed from its structure was shown to be stable with the use of spectroscopy properties.
Abstract: Oxidation of 2,2'-dihydroxy-4,4'-dimethoxy-6,6'-dimethylbenzophenone (1) with alkaline ferricyanide gave the expected 4',6-dimethoxy-4,6'-dimethylspiro[benzofuran-2(3H),1'-cyclohexa-3',5'-diene]-2',3(2H)-dione (2) as well as 2'-hydroxy-6-methoxy-4,5'-dimethylspiro[benzofuran-2(3H),1'-cyclopent-4'-ene]-3(2H),3'-dione (3). The structure of compound (3) was deduced from its spectroscopic properties and was confirmed by X-ray diffraction.
TL;DR: In this paper, the structure of compound (3) was deduced from its spectroscopic properties and was confirmed by X-ray diffraction, and the structure was confirmed from its structure was shown to be stable with the use of spectroscopy properties.
Abstract: Oxidation of 2,2'-dihydroxy-4,4'-dimethoxy-6,6'-dimethylbenzophenone (1) with alkaline ferricyanide gave the expected 4',6-dimethoxy-4,6'-dimethylspiro[benzofuran-2(3H),1'-cyclohexa-3',5'-diene]-2',3(2H)-dione (2) as well as 2'-hydroxy-6-methoxy-4,5'-dimethylspiro[benzofuran-2(3H),1'-cyclopent-4'-ene]-3(2H),3'-dione (3). The structure of compound (3) was deduced from its spectroscopic properties and was confirmed by X-ray diffraction.