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The structures of two alkyne-hexacarbonyl-dicobalt complexes are reported, each with potential ATRP initiator substrates as substituents on the alkynes. The complexes each form tetrahedral C2Co2 cluster cores with classical sawhorse conformations, while a feature of the crystal packing is the formation of inversion dimers for both molecules., The title compounds, [Co2(C8H11BrO3)(CO)6], (1), and [Co2(C12H16Br2O4)(CO)6], (2), result from the replacement of two carbonyl ligands from dicobalt octa­carbonyl by the alkynes 4-hy­droxy­but-2-ynyl 2-bromo-2-methyl­propano­ate and but-2-yne-1,4-diyl bis­(2-bromo-2-methyl­propano­ate), respectively. Both mol­ecules have classic tetra­hedral C2Co2 cluster cores with the CoII atoms in a highly distorted octa­hedral coordination geometry. The alkyne ligands both adopt a cis-bent conformation on coordination. In the crystal structure of (1), classical O—H⋯O and non-classical C—H⋯O contacts form inversion dimers. These combine with weak O⋯O and Br⋯O contacts to stack the mol­ecules into inter­connected columns along the b-axis direction. C—H⋯O and C—H⋯Br contacts stabilize the packing for (2), and a weak Br⋯O contact is also observed. Inter­connected columns of mol­ecules again form along the b-axis direction.

The Expendable Launch Systems division of The Boeing Company is well into the development of the new family of Delta IV launch vehicles to support commercial and government missions. The Delta IV adds to the existing Delta family of vehicles, the Delta II in four configurations and the Delta III with twice the performance of the Delta II. The addition of the Delta IV adds five vehicles to the Delta family: the Delta IV medium, three Delta IV Medium-Plus vehicles with solid rocket augmentation, and the Delta IV Heavy vehicles. This family now addresses the full market range of payload requirements from 2,000 to 29,000 pounds to geosynchronous transfer orbit (GTO). Full-scale commercial development was initiated in 1997, with the first Delta flight planned for the second quarter of 2001. This paper presents the status of the development program of the launch vehicles, the new green field, focused factory for common booster core production at Decatur, Alabama, the new launch facility construction at Cape Canaveral Air Force Station and Vandenberg Air Force Base, and the new LO2/LH2 RS-68 common booster core engine. The status of the Delta III return to flight is also presented.

Sonogashira coupling of a terminal alkyne with cycloplatinated ferrocenylamine complexes gave the acetylides Pt{[RCC][Me2NCH2(σ-Fc)]dmso}, which were characterised by analysis, spectroscopy and, for the R = SiMe33, Fc 5 complexes, X-ray structural analyses. A butadiyne complex was also isolated in reactions of 3. Equivalent reactions with LDA led to an unusual deplatination reaction to give the ethynylferrocenylamine. The Pt(II) centre functions as a redox switch at E+/0 = ∼0.21 V and the spectroscopic and electrochemical data show that the acetylide is a π-donor ligand. There is a strict delineation of the electronic requirements for the trans Pt–N and trans Pt–C(Cp) groups in these cycloplatinated compounds. Oxidation of 3 gives rise to low energy bands based on the Pt(II) unit; an additional broad band at 1100 nm occurs in 5+ but not 52+.

The synthesis and characterization of a family of ethynylbi- and ethynylterferrocenyls, I−Fc2C⋮CR, Fc2C⋮CR, and Fc2(C⋮CR)2 (R = Fc, SiMe3), I−Fc3C⋮CSiMe3, Fc3C⋮CSiMe3, Fc3(C⋮CSiMe3)2, and their Co2(CO)6 and Co2(CO)4dppm complexes are described. The structure adopted by Fc2{[Co2(CO)4dppm C2SiMe3]}2 minimizes the steric interactions between the biferrocene and dppm moieties. Electrochemical studies show that identical redox centersferrocenyl termini, Co2(CO)4dppm units, or ferrocenyl groups in the corecommunicate independently with each other.

A family of N-ferrocenyl-1,8- and N-ferrocenyl-2,3-naphthalimide and N,N-diferrocenyl-1,4,5,8-naphthaldiimide complexes has been prepared by reaction of naphthalic anhydrides or naphthalimide anions with a ferrocenylamine. The N-ferrocenyl substituents are 1,8 (Fc, FcCH2, FcCHMe, Fc(CH2)11), 1,4,5,8 (Fc, FcCH2, FcCHMe, Fc(CH2)11), 3-NO2-1,8- (FcCH2, FcCHMe), 4-NO2-1,8 (Fc, FcCH2, FcCHMe, Fc(CH2)11, 1,1‘-BrFcCH2), 4-Br-1,8 (FcCH2, Fc(CH2)11), and 2,3 (Fc, FcCH2, FcCHMe, Fc(CH2)11). A novel stacking aggregation occurs with the 1,4,5,8-Fc and -FcCH2 derivatives, and intramolecular donor−acceptor charge transfer is evident in the aggregate. Steric hindrance precludes this aggregation in other 1,4,5,8 analogues. An X-ray structure of the 3-NO2-1,8 derivative shows an L-shaped molecule which packs in a columnar array. Micelle formation occurs with long-chain derivatives. The electronic spectra and electrochemistry show that the N-ferrocenyl substituents do not perturb the energy levels of the fluorophore, altho...

Trisaccharides, methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-alpha-D-xy lopyranoside and methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-beta-D-xyl opyranoside, which are related to the side chain of xyloglucan have been synthesised. The beta-galactopyranosyl linkage of each was constructed using silver trifluoromethanesulfonate-promoted glycosylations of 2-O-acetyl-3,4,6-tri-O-benzyl-beta-D-galactopyranosyl chloride and the corresponding anomer of methyl 3,4-tri-O-benzyl-D-xylopyranoside. The resulting disaccharides were deacetylated and fucosylated using assisted halide reactions with tri-O-benzyl-alpha-L-fucopyranosyl bromide. Hydrogenolytic debenzylation of the resulting protected trisaccharides gave the methyl glycosides of the fucose-containing xyloglucan side chain. The structure of methyl alpha-L-fucopyranosyl-(1-->2)-beta-D-galactopyranosyl-(1-->2)-alpha-D-xy lopyranoside as the monohydrate was confirmed by an X-ray crystallographic study.

The N-ferrocenylamine–carbohydrate conjugates N,N-bis(ferrocenylmethyl)-N-(2,3,4,6-tetra-O-acetyl-1-deoxy-β-D-glucopyranosyl)amine, N-(2,3,4,6-tetra-O-acetyl-1-deoxy-β-D-glucopyranosyl)aminometyhylferrocene and N,N-bis(ferrocenylmethyl)-N-[4-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)-2,3,6-tri-O-acetyl-1-deoxy-β-D-glucopyranosyl]amine have been synthesized from FcCH2NMe3+I− and the appropriate aminosugars. Deprotection using an ion exchange resin gave the analogous water soluble complexes. A short C–N bond at the anomeric carbon in the crystal structure of the first compound is attributed to an exo-anomeric n–σ* interaction between the exo C–N and endo C–O bonds. N-Ferrocenylmethylalkanolamines FcCH2NH(CH2)nOH and (FcCH2)2N(CH2)nOH (n = 2 or 5) were synthesized in good yield using reductive amination reactions. Owing to the basicity of the N-ferrocenylamine component the electrochemistry is both solvent and pH dependent; protonation occurs in polar solvents and in all solvents with the first two compounds. Rapid oxidation to the non-protonated ferrocenium complexes occurs in aqueous solvents under physiological pH.

A series of water soluble ferrocenylamine–glucose conjugates, [N-2-(β-D-glucopyranosyloxy)ethyl-, [N-3-(β-D-glucopyranosyloxy)propyl-, [N-5-(β-D-glucopyranosyloxy)pentyl-N-methylaminomethyl]ferrocene, has been synthesized from the methiodide salt of N,N-dimethylaminomethylferrocene and N-(3,4,6-tri-O-benzyl-β-D-glucopyranosyloxy-ethyl, -propyl and -pentyl)amine respectively. N-Methylation of the products from the latter reaction was achieved by formylation followed by reduction with lithium aluminium hydride. Catalytic hydrogenolysis over palladium removed the benzyl protecting groups from the carbohydrate moiety to give the target conjugates. An alternative synthesis of [N-2-(β-D-glucopyranosyloxyethyl)aminomethyl]ferrocene using boron trifluoride–diethyl ether promoted glycosylation of penta-O-acetyl-D-glucopyranose and [N-(2-hydroxyethyl)-N-methylaminomethyl]ferrocene followed by deacetylation of the carbohydrate protecting group using basic ion exchange resin was also developed. The pKa values of the water soluble conjugates were determined.

An in situ subtractively normalised interfacial FTIR spectroscopy (SNIFTIRS) investigation of [Co 3 (CO) 9 C] 2 in dichloromethane is used to illustrate the application of these techniques to follow ECE transformations of metal carbonyls in a thin layer cell. SNIFTIRS data obtained at a platinum electrode show that the major species at ambient temperature is not the radical anion [Co 3 (CO) 9 C] 2 − . Within the timescale of the measurement [Co 3 (CO) 9 C] 2 − transforms to a new species with a bridged carbonyl configuration; this species forms a chemically reversible redox couple in the thin layer. The consequences for the redox chemistry of [Co 3 (CO) 9 C] 2 are discussed.

Toxicity, antitumour, platinum distribution, hepatotoxicity and histology data are presented for a series of ferrocenylamines: [(η-C 5 H 4 (CH 2 ) n NH 2 )FeCp] (n = 0,1) (1,2); [(η-C 5 H 4 CH 2 NHPh)FeCp] (3); [(η-C 5 H 4 CH 2 NMe 2 )FeCp (4); {[η-C 5 H 4 CH(Me)NMe 2 ]FeCp}(5); [η-C 5 H 4 CH 2 NMe 2 ) 2 Fe](6); {[1,2η-C 5 H 3 (CHMeNMe 2 )(PPh 2 )] FeCp}(7); {[1,2η-C 5 H 3 (CHMeNMe2)(PPh 2 )]-Fe[η-C 5 H 4 PPh 2 ]}(8); and their complexes cis-PtCl 2 L 2 (9); trans - Pt(L)(dmso)X 2 (10); [σ -(L)Pt(dmso)X] (11,12) {σ-(L)[Pt(dmso)X] 2 } (13); [σ-(L)PtP(OPh) 3 Cl] (14) (L = ferrocenylamine). The toxicity order is 1-3 » 4-8 for the ferrocenylamines; the lower toxicity of tertiary amines may be due to protonation in vivo. Pt(II) complexes all show increased toxicity over the ligand. Liver, not kidney, damage is the norm from i.p. injection of 1-14 and detailed platinum distribution, blood serum and histology studies with 9 and 11 show that the platinum distribution does not correlate with liver dysfunction. Complexes 9-14, but not 1-8, were active against P-388 mouse leukaemia tumour and cisplatin-resistant sarcoma, but inactive against L-1210 mouse leukaemia and B-16 melanoma.

Coupling of lithium ethynylferrocene to alkyl and aryl chlorosilanes and to silicon tetrachloride leads to the formation of a variety of ferrocenylethynylsilanes, [(η5-C5H5)Fe(η5-C5H4C2)]4−nSiRn (n=0–3, R=Me, Ph). An additional series of compounds [(η5-C5H5)Fe(η5-C5H4C2)]4−nSi(n-Bu)xRy (n=0–3, x+y=n, R=Me, Ph) result from competitive reactions of excess n-BuLi at the silicon centre. Dicobalt octacarbonyl reacts with the ferrocenylethynylsilanes to give dicobalt hexacarbonyl derivatives, but for the tris- and tetrakis-compounds coordination of Co2(CO)6 is limited to two of the alkyne units as a result of steric crowding around the silicon centre. The crystal and molecular structure of the complex [(η5-C5H5)Fe(η5-C5H4C–(Co2(CO)6)C]2Si[(CC-η5-C5H4)Fe(η5-C5H5)]2 has been determined from X-ray data. Electrochemical investigation of the ferrocenylethynylsilanes and their dicobalt complexes shows that the equivalent ferrocenyl redox centres in these molecules are non-interacting.

The synthesis and comparative investigation of the reactivity and communication between redox centres in peri-1,8- (3) and 1,5- (4) bis(ferrocenylethynyl)naphthalene and acenaphthylenes, and their Co2(CO)6–xLx derivatives, are described. The cofacial alkyne configuration in 3 encourages acenaphthylene formation; 1-ferrocenylacenaphthylene and triferrocenylbenzo[a]acenaphthylene directly from 3 and (E,E)-diferrocenyliodobut[a]acenaphthylene-1,2-diene 9, diferrocenylcyclopent[a]acenaphthylen-8-one 10, furan[a]acenaphthylene and γ-lactone[a]acenaphthylene from reactions with iPr2NH2+I–/Co2(CO)6–xLx. 9 has an (E,E) configuration (X-ray structure) and steric crowding causes significant distortion of the diene fragment. Co2(CO)6 and Co2(CO)4(dppm) complexes with 4 but not 3 have been characterised. 1,5-{PhC2Co2(CO)4[P(OMe)3]2}2C10H6 has the phosphite ligands in pseudo-axial sites and there is an unusually short Co–Co bond (2.437 A). Electrochemical and spectroscopic data show that there is effective communication between two ferrocenyl or two cluster redox centres, reinforced by the transannular interaction, but the ferrocenyl and cluster electrophores act independently of one another. The primary reduction centre for the acenaphthylenes is the peri ring system. The mixed valence 10+ has been characterised.

Two synthetic routes, the direct reaction of a carbohydrate with +COCCo3(CO)9, or the reaction of Co2(CO)8 with 1,1,1-tribromomethyl sugar derivatives have been used to prepare [AcOglc = tetra-O-acetyl-D-glucopyranose, Co3 = CCo3(CO)9] 1-β-AcOglc-N-(CO)-Co3,, 2-β-AcOglc-N-(CO)-Co3,, 1-α- (16) and 1-β-AcOglc-OCH2Co3, 1-α-BnOglc-O-(CO)Co3 and 1-α- and 1-β-AcOmaltose-OCH2Co3. An unusual oxazoline cluster was isolated from the reaction with 2-aminoglucose. An X-ray structure confirmed the structure and absolute configuration of 16. Deprotection of 1-β-AcOglc-OCH2Co3 on ion exchange resin gave water soluble 1-β-glc-OCH2Co3; higher yields of water soluble complexes were obtained by direct reaction of deprotected trihalomethyl derivatives with Co2(CO)8. Dppm complexes of the OCH2Co3 glucose derivatives were also prepared. Reaction of +COCCo3(CO)9 with methyl-α-D-glucopyranoside gave the series 1-MeOglc-3-Co3, 1-MeOglc-3,6-(Co3)2, 1-MeOglc-2,3,6-(Co3)3 and 1-MeOglc-3,4,6-(Co3)3, structurally characterised by 2-D 1H and 13C NMR. The carbohydrate-cluster complexes show reversible redox activity in organic and aqueous media.

Metathetical reaction of the cyclometallated ferrocenylamine complexes [Pt{FeCp(σ,η5-C5H3CHRNMe2)}(dmso)Cl] (R = H 1 or Me 3) and [Pt2{Fe(σ,η5-C5H3CH2NMe2)2}(dmso)2Cl2] 2 with TlX (X = OAc or malonate), or the direct reaction with P(C6H4SO3-m)33– (tppms) and Et2NCS2–(dedtc), gave [Pt{FeCp(σ,η5-C5H3CHRNMe2)}(dmso)(OAc)], [{Pt[FeCp(σ,η5-C5H3CHRNMe2)](dmso)}2(mal)] (mal = malonate), Na5[Pt{FeCp(σ,η5-C5H3CHRNMe2)}(tppms)2], [Pt{FeCp(σ,η5-C5H3CHRNMe2)}(dedtc)] and bis-Pt analogues. These complexes were characterised by analysis, ES-MS and 1H, 13C and 195Pt NMR. Metathetical reaction of 1–3 with silver(I) salts generally gave ferrocenium derivatives. Substitution trans to the Pt–N or Pt–C bond is determined by the acceptor character of the co-ordinating group and this together with steric constraints limit the range of carboxylato complexes. The acetato complex [Pt{FeCp(σ,η5-C5H3CH2NMe2)}(dmso)(OAc)] crystallises with one molecule of H2O and a single crystal structure indicates a hydrogen bond between a solvent H2O and acetate ligand. Aqueous solutions of the water-soluble OAc, malonate and tppms complexes were studied by electrochemical and spectroscopic techniques. Their chemistry is regulated by pH-dependent equilibria involving aqua and hydroxo complexes and competing oxidation to the ferrocenium compound by molecular oxygen.

The complexes t- and p-[Co(tren)(NH3){OP(H)(O)2}]ClO4 (1·ClO4 and 2·ClO4, respectively) and syn(OP(H)(O)2), anti(OH2)-[Co(cyclen)(OH2){OP(H)(O)2}]ClO4 (3·ClO4, cyclen = 1,4,7,10-tetraazacyclododecane) have been prepared. Single crystal structures have been determined for 1·ClO4·2H2O and 3·ClO4·3H2O. In weakly acidic aqueous solution 3 equilibrates with its syn(OH2),anti(OP(H)(O)2) isomer and the chelate [Co(cyclen){O2P(H)O}]+. Kinetic studies of acid catalysed H/D exchange in H2DPO3 (4-D) and [Co(NH3)5{OP(D)(OH)O}]2+ (5-D) in water (55.0 °C, I = 1.0 mol dm–3, NaClO4) showed that 4-D (kex = (1.6 ± 0.2) × 10–4 dm3 mol–1 s–1) is four-fold more reactive than 5-D (kex = (4.0 ± 0.5) × 10–5 dm3 mol–1 s–1) and that exchange likely involves P(OH)3 and [Co(NH3)5{OP(OH)2}]2+ intermediates, respectively. Bromine oxidation of [Co(NH3)5{OP(H)(O)2}]+ (5-H, 25 °C, pH 1.22–4.34, I = 1.0 mol dm–3, NaClO4) follows the rate equation kobs = kHKaH [5-H]T/(KaH + [H+])(1 + KBr3[Br–]), where KaH ((4.2 ± 0.5) × 10–4 mol dm–3) corresponds to the independently measured acid dissociation constant of the 5-H conjugate acid, KBr3 (17.6 dm3 mol–1) = [Br3–]/[Br2][Br–], and where kH (1316 ± 20 dm3 mol–1 s–1) represents the specific rate constant for reaction of Br2 with 5-H. For 5-D as substrate kD = 560 dm3 mol–1 s–1 (kH/kD = 2.4). Similar studies with H3PO3 (4-H, 25 °C, pH 1.27–2.55, I = 1.0 mol dm–3, NaClO4) showed that bromine oxidation follows the rate equation: kobs = kHKa1HKa2H[4-H]T/([H+]2 + Ka1H[H+] + Ka1HKa2H )(1 + KBr3[Br–]), with Ka1H (0.108 mol dm–3) and Ka2H (1.67 × 10–6 mol dm–3) corresponding to the independently measured first and second acid dissociation constants of 4-H, and with kH (2.1 × 105 dm3 mol–1 s–1) representing the specific rate constant for reaction of Br2 with HPO32–. For 4-D as substrate kD = 1.22 × 105 dm3 mol–1 s–1 (kH/kD = 1.7). NMR studies showed that there is no loss of 17O label to solvent from H3P17O3, either during H/D exchange or on bromine oxidation. Mechanisms for the reactions are discussed.

In the title compound, [Ni(C(5)H(5))(C(5)H(7)O)(C(18)H(15)P)], the molecule adopts the expected half-sandwich structure with no unusual metal-ligand distances. No classical hydrogen bonds are found in the structure; instead, the OH group of the butynol unit is involved in an unusual O-H...pi interaction with the C[triple-bond]C group of an adjacent molecule. The crystal structure is further stabilized by C-H...O and C-H...pi interactions, leading to an extensive network of spiral columns.

p K b values for the ferrocenylamines, [( η -C 5 H 4 (CH 2 ) x NH 2 )FeCp] x = 1 , 2 , 3 ; [( η -C 5 H 4 CH 2 NHR)FeCp] R=Me, 4 , Ph, 5 ; {[ η -C 5 H 4 CHR′NR 2 ]FeCp} R′/R=H/Me, 6 , R′/R=H/Ph, 7 , Me/Me, 8 ;[{ η -C 5 H 4 CHRNMe 2 ) 2 Fe] R=H 9 , Me 10 ; [{1,2 η -C 5 H 3 (CH 2 NMe 2 )(PPh 2 )}FeCp] 11 , {1,2 η -C 5 H 3 [CH(Me)NMe 2 ](PR 2 }}Fe[ η -C 5 H 4 (PPh 2 ) n ] n =0, R= i Pr 12 , Ph 13 , n =1, R=Me 14 , are correlated with inductive, neighbouring group and steric effects. Corresponding salts have been synthesised. The p K b has a marked influence on their chemistry. Protonation competes with complexation but cis -PtCl 2 L 2 L= 1 – 3 , 5 , 7 , and cis -Pt(N–N)Cl 2 L= 8 , 9 , have been characterised. Two reversible couples [Fc + A/FcA], [Fc + AH + /FcAH + ] (A=amine function) and an irreversible oxidation/protonation of A are linked by a EECE mechanism, but potentials for the first two are independent of the amine and similar to ferrocene. Nucleophilic attack by ferrocenylamines at the nitrile, protonation and ligand substitution are all observed with cis- [PtCl 2 (NCR) 2 ].

A series of phosphite complexes R 2 C 2 Co 2 (CO) 6− n [P(OMe) 3 ] n (R=CF 3 , MeO 2 C), n =1–4, have been prepared and characterised. Cyclic and square-wave voltammetry shows that the kinetic stability of the radical cations increases with substitution and when R=CF 3 . The radical cation {(CF 3 ) 2 C 2 Co 2 (CO) 2 [P(OMe) 3 ] 4 }PF 6 4a + has been characterised and its crystal structure compared with that of the neutral parent. Analysis of the anisotropic ESR spectrum of 4a + is consistent with an unpaired electron in a SOMO with little d z 2 character.

Substitution of a triethyl for a trimethyl headgroup in alkyltrimethylammonium or (ω-hydroxyalkyl)trimethylammonium bromide surfactants leads to a significant reduction in the Krafft temperature. This substitution allowed us to produce asymmetric bolaform surfactants that form micellar solutions at room temperature. It is reasoned that the proximity of the bromide counterion to the quaternary ammonium center stabilizes the hydrated crystal of the conventional and bolaform surfactants through Coulombic interactions. The bolaform surfactants experience further stabilization as a result of bonding between the hydroxyl functionality and the quaternary nitrogen and bromide. Substitution of ethyl for methyl groups in the headgroup increases the ion−ion and ion−dipole distances, lowering the stability of the hydrated crystal, which in turn lowers the Krafft temperature.

In situ infrared spectroelectrochemistry [SNIFTIRS (subtractively normalized interfacial FTIR spectroscopy)] has been used to obtain spectra at a platinum electrode of the reduction products of [Co3(CPh)(CO)9] in absolute methanol, in CO saturated methanol, in the presence of a ligand [P(C6H4SO3-m)3]3– (L) and in dichloromethane. The cluster species 49e [Co3(CPh)(CO)9]˙–, 50e [Co3(CPh)(CO)9]2– and, tentatively, the 47e [Co3(CPh)(CO)8]– and 49e [Co3(CPh)(CO)8L]˙– were identified and their interrelationships elucidated. Adsorption of the cluster at the surface may be responsible for the unexpected formation of CO2 upon decomposition of Co(CO)4–.

The title compound, C21H20N4O5S, crystallizes with two mol­ecules in the asymmetric unit. The crystal structure is stabilized by a network of C—H⋯O hydrogen bonds.

The molecule of the title compound, C15H24O2, lies across a mirror plane with the two tert-butyl substituents flanking the phenolic OH group in this hindered phenol. In the crystal structure, O—H⋯O hydrogen bonds between the benzyl OH group and the phenolic O atom link the mol­ecules into chains.

The title compound, [Fe(C5H5)(C7H6IO)], crystallizes with two unique mol­ecules in the asymmetric unit. Both iodo substituents of the iodo­acetyl groups point away from the Fe atoms of the ferrocenyl groups. In the crystal structure, C—H⋯O hydrogen bonds and unusual I⋯π inter­actions stabilize the structure.

Extraction of Trianthema portulacastrum with dichloromethane has led to the isolation of a new flavonoid, 5,2′-dihydroxy-7-methoxy-6,8-dimethylflavone, along with 5,7-dihydroxy-6,8-dimethylchromone (leptorumol) which has been previously reported from a fern species. X-ray analysis of leptorumol is also reported.

Fe(C5H4PPh2)2 (dppf) undergoes facile thermal substitution reactions with R2C2Co2(CO)6 (R  MeO2C, CF3) to yield a variety of products. When R  MeO2C, initial coordination gives μ2-(MeO2C2)2C2Co2(CO)5(η1-dppf); its crystal and molecular structure, monoclinic, P2 1 /c, a = 8.954(3), b = 20.211(2) c = 23.836(5) A , β = 100.55(2)°, Z = 4, R1 = 0.0345 for 5764 reflections 1 > 2σ(1), confirms the monodentate coordination mode for dppf. At low dppf/alkyne-complex ratios, oligomeric products with dppf ligands linking up to five (μ2-MeO2C)2C2Co2 modules have been characterised but, as the proportion of the phosphine ligand increases. unstable products, which include a η1-μ-η1 dppf configuration, are obtained as well. In contrast, for R  CF3, only [(CF3)2C2]Co2(CO)4(η2-dppf) is found in significant yield. A molecule with two different reduction centres, [μ2-(MeO2C)2C2Co2(CO)5](μ-dppf)[Co3(μ3-CPh)(CO)8], was also characterised. Electrochemistry of the dppf complexes was characterised by fast ligand dissociation upon reduction of the (μ-alkyne)Co2 redox centre and oxidation of coordinated dppf. There was no evidence for communication between redox centres.

The title compounds, C11H11BrO3, (I), and C11H11NO5, (II), respectively, are derivatives of 6-hydroxy-5,7,8-trimethylchroman-2-one substituted at the 5-position by a Br atom in (I) and by a nitro group in (II). The pyranone rings in both molecules adopt half-chair conformations, and intramolecular O—H...Br [in (I)] and O—H...Onitro[in (II)] hydrogen bonds affect the dispositions of the hydroxy groups. Classical intermolecular O—H...O hydrogen bonds are found in both molecules but play quite dissimilar roles in the crystal structures. In (I), O—H...O hydrogen bonds form zigzagC(9) chains of molecules along theaaxis. Because of the tetragonal symmetry, similar chains also form alongb. In (II), however, similar contacts involving an O atom of the nitro group form inversion dimers and generateR22(12) rings. These also result in a close intermolecular O...O contact of 2.686 (4) Å. For (I), four additional C—H...O hydrogen bonds combine with π–π stacking interactions between the benzene rings to build an extensive three-dimensional network with molecules stacked along thecaxis. The packing in (II) is much simpler and centres on the inversion dimers formed through O—H...O contacts. These dimers are stacked through additional C—H...O hydrogen bonds, and further weak C—H...O interactions generate a three-dimensional network of dimer stacks.

IN general, tenesmus is a symptom of large intestinal disease but in particular it is associated with conditions of the rectum and/or anus. The differential diagnosis of faecal tenesmus includes mechanical obstruction and inflammatory conditions of the colon, rectum and anus.

The disaccharides methyl 2- O -( α -l-fucopyranosyl)- β -d-galactopyranoside and methyl 2- O -( α -l-fucopyranosyl)- α -d-galactopyranoside have been synthesised using the assisted halide reaction of tri- O -benzyl- α -l-fucopyranosyl bromide with methyl 3,4,6-tri- O -benzyl- β -d-galactopyranoside and methyl 3,4,6-tri- O -benzyl- α -d-galactopyranoside to construct the interresidue glycosidic linkages. A crystal structure of methyl 2- O -( α -l-fucopyranosyl)- β -d-galactopyranoside was determined using Mo-Kα X-ray data at 183 K. The space group is P 1 (No. 1) with the unit cell containing two molecules of the disaccharide with unique conformations and a water molecule. The structure was refined to R = 0.0566 for 2969 reflections. The l-fucopyranosyl and d-galactopyranosyl residues have the nominal 1 C 4 and 4 C 1 conformations, respectively. The interresidue torsion angles are comparable with those generated in a recent molecular modelling study.

The structure of Ni (fdma)2Br2 (fdma = 1,1′-bis(dimethylarsino)ferrocene) is described. Ni (fdma)2Br2 crystallizes in the space group P21/c with a = 28.544(4), b = 8.989(1), c = 19.613(3) A, β = 106.62(1° and Z = 6 and R/wR2 = 0.0439/0.0738 for 4355 (I ∗> 2π (I)) data. The unit cell contains two crystallographically independent but structurally distinct conformers. The geometry of the nickel ion in both conformers is that of a tetragonally-compressed octahedron. In one form the ferrocene moieties of both ligands are parallel while in the other they are approximately at right angles to each other. Both conformers show staggered arrangements of the ferrocenyl rings. The NiAs bonds are long with an average distance of 2.588 (2) A. In the solid state one of the conformers forms a chain of molecules held together by weak electrostatic Br…H(ferrocenyl) interactions; the Br…H distance is 2.911(4) A.

Equilibration in the system : p-[Co(tren)(NH3)OH2]3+ + Cl- ⇄ p-[Co(tren)(NH3)Cl]2+ + H2O (p-stereochemistry has the labile group (OH2, Cl-) trans to a tren NH2) in aqueous solution of variable (I = 0−2.0 M) and constant (I = 2.0 M, NaClO4) ionic strength at 37.5 °C is described by the following rate law: kobs = kaq + kanKCl[Cl-]/(1 + KCl[Cl-] + KClO4[ClO4-]); KCl (0.64 M-1) and KClO4 (0.21 M-1) correspond to ion pairing of Cl- and ClO4- to the aqua complex and kaq (1.4 × 10-5 s-1) and kan (1.2 × 10-4 s-1) to the rate constants for aquation of the chloro complex and anation of the ion-paired (Cl-) aqua complex respectively. The rate constant for loss of coordinated 17OH2 from the labeled aqua complex is the same (kOH2 ∼1.2 × 10-4 s-1) irrespective of the presence (2.0 M) or absence of NaClO4 ([H+] = 0.10 M, 37.5 °C) but increases with increasing [Cl-] to reach a limit (∼2.4 × 10-4 s-1) at high concentrations (range 0−1.90 M; I = 2.0 M, NaClO4). Water exchange in the p-[Co(tren)(NH3)OH2]3+·Cl- ion pair (k...

The title compound, [Fe(C5H5)(C28H23N2O2)], contains a 1,8-naphthalimide system, substituted in the 4-position with an N-bound piperidine ring. The imide N atom of the naphthalimide group carries a 4-ferrocenylphenyl substituent. The compound crystallizes with the plane of the naphthalimide moiety orthogonal to those of the benzene and cyclo­pentadiene rings, which facilitates intermolecular π stacking interactions between adjacent pairs of naphthalimide rings.

The aromatic ring in the diterpenoid methyl O-methylpodocarpate (podo) coordinates readily to the Mn(CO)3+ moiety to afford in high yield a nearly 1:1 isometric distribution of [(η6-podo)Mn(CO)3]BF4 ([2]BF4), in which the metal is situated on the α or β face. The nucleophiles PhLi, PhMgBr, MeLi, MeMgCl, LiCH2C(O)CMe3 and NaBH4 were found to add cleanly to the activated aromatic ring in 2+ to give neutral cyclohexadienyl complexes. Nucleophilic addition occurs predominantly meta to the OMe substituent in the case of the α-isomer of 2+, and at both ortho and meta sites in the case of the β-isomer. The X-ray structure is reported for a typical α-meta and a typical β-ortho cyclohexadienyl product, namely β-(η5-podo · Ph)Mn(CO)3 and α-(η5-podo · CH2C(O)CMe3)Mn(CO)3. The high yield and regioselectivity of the nucleophilic additions suggests that the manganese-mediated functionalization of aromatic diterpenes and steroids will prove to provide a useful synthetic methodology.

The title compound, 1,2-bis(4-nitro­phenyl)­ferrocene, [Fe(C5H5)(C17H11N2O4)], crystallizes with the planes of the two vicinal 4-nitro­phenyl rings subtending angles of 46.04 (6) and 36.30 (7)° at the plane of the substituted cyclo­penta­diene ring of the ferrocene moiety.

The title compound, C11H12O3, is essentially planar, with an r.m.s. deviation of 0.179 Å from the mean plane through the 14 non-H atoms in the molecule. The benzene ring and the pyranone mean plane are inclined at 13.12 (6)° to one another and the pyranone ring adopts a flattened chair conformation. In the crystal, O—H...O hydrogen bonds and C—H...O contacts formR12(6) rings and link molecules into chains alongb. Additional C—H...O contacts generate inversion dimers, withR22(8) ring motifs, and form sheets parallel to (-102) which are linked by C—H...π interactions.

Reactions between Ph n SiH 4− n or HR 2 SiXSiR 2 H and HCCo 3 (CO) 9 are described. Both the monocluster, HMe 2 SiXSiMe 2 CCo 3 (CO) 9 , and the dicluster, (CO) 9 Co 3 CMe 2 SiXSiMe 2 CCo 3 (CO) 9 , complexes were obtained from the silanes HMe 2 SiXSiMe 2 H (X=O, 1,4-C 6 H 4 ). RSiH 2 CCo 3 (CO) 9 (R=Ph, Me) or sterically demanding silanes do not couple with HCCo 3 (CO) 9 . Generally with Ph n SiH 4− n ( n =1, 2) electrophilic attack on the cluster core resulted in the formation of the novel μ-silylene complexes HCCo 3 (CO) 8 (μ-SiR 2 ), and fragmentation of the Co 3 C unit, instead of the expected silicon-bridged diclusters. Electrochemical investigation of the dicluster compounds and their phosphite derivatives showed there was no interaction between the cluster redox centres.

The title compound was found to exhibit conformational polymorphism which greatly influenced the efficiency of the thermorearrangement to 2,2′-bis-S-(N,N-dimethylthiocarbamato)-1,1′-binaphthalene. Recognition of this phenomenon has allowed a reproducible synthesis of 1,1′-binaphthalene-2,2′ dithiol.

In the title compound, [PtBr2(C27H26P2)], the mol­ecule adopts a distorted square-planar metal coordination, with the six-membered metallocyclic ring in a twist-boat conformation.

In the title molecule, C16H14O4S, the dihydrocyclopentathiophenone ring system is almost planar, with an r.m.s. deviation of 0.060 Å from the best fit plane through all nine non-H atoms. The cyclopentanone ring adopts a severely flattened envelope conformation with the C atom carrying the OH and ethylcarboxylate substituents at the flap. This atom lies only 0.185 (3) Å from the plane through the other four C atoms. The phenyl substituent is inclined at 43.37 (5)° to the dihydrocyclopentathiophenone mean plane. In the crystal, molecules are linked by pairs of O—H...O hydrogen bonds, forming inversion dimers with R22(10) ring motifs. Weak C—H...O hydrogen bonds also link molecules into chains along c, while an approximately orthogonal set of C—H...O contacts form chains along b, resulting in layers lying parallel to (100). Inversion dimers also form through weaker R22(12) C—H...S contacts, which combine with C—H...O contacts to form stacks along b.

In the title molecule, C11H11ClO3, the fused pyran ring adopts a half-chair conformation. In the crystal, intermolecular O—H...O hydrogen bonds link molecules into chains along [100]. These chains are interconnected by weak intermolecular C—H...O contacts which generate R22(8) ring motifs, forming sheets parallel to (001). Tetragonal symmetry generates an equivalent motif along b. Furthermore, the sheets are linked along the c axis by offset π–π stacking interactions involving the benzene rings of adjacent molecules [with centroid–centroid distances of 3.839 (2) Å], together with an additional weak C—H...O hydrogen bond, resulting in an overall three-dimensional network.

Unions in the electric utility industry consistently won a greater percentage of elections between 1970 and 1989 than did unions in other industries. Several factors significantly affected union victory rates at electric utilities: when the election was held, the union involved, the size of the utility, the percent of the state’s labor force unionized, the number of eligible voters, whether the election involved multiple-unions, and whether the election was Regional- or Board-directed.

The reaction of the cluster complex HCC[Co2(CO)6]CCo3(CO)9 with (or without) BrCCo3(CO)9 under Cadiot-Chodkiewicz coupling conditions gave the unusual alkynyl carboxamide complex C2H5N(H)C(O)CC[Co2(CO)6]CCo3(CO)9 rather than a coupled product containing two tricobalt cluster units. Steric demands imposed by the Co3 cluster allow attack at the least hindered alkyne carbon and stabilise the formed ynamine, so allowing subsequent CO insertion. The product has been characterised by X-ray crystallography.

The bidentate phosphine ligand 1,1-bis(diphenylphosphinomethane) (dppm) forms both mono- and bis-substituted complexes with the tricobalt-carbon cluster PhCCo3(CO)9. The crystal and molecular structures of PhCCo3(CO)7(dppm) and PhCCo3(CO)5(dppm)2 have been determined from X-ray data collected at 123(5) K. The results provide a detailed characterization of these related complexes and reveal that the dppm ligand coordinates by bridging CoCo bonds in both molecules.

The title compound, C13H10ClNO, (I), is a polymorph of the structure, (II), first reported by Gowda et al. [Acta Cryst. (2008), E64, o462]. In the original report, the compound crystallized in the orthorhombic space group Pbca (Z = 8), whereas the structure reported here is monoclinic P21/c (Z = 4). The principal difference between the two forms lies in the relative orientations of the phenyl and benzene rings [dihedral angle = 8.90 (13)° for (I) and 61.0 (1)° for (II)]. The inclination of the amide –CONH– units to the benzoyl ring is more similar [15.8 (7)° for (I) and 18.2 (2)° for (II)]. In both forms, the N—H bonds are anti to the 3-chloro substituents of the aniline rings. In the crystal, intermolecular N—H...O hydrogen bonds form C(4) chains along c. These chains are bolstered by weak C—H...O interactions that generate R21(6) and R21(7) ring motifs.