Ethanol Adduct Research Articles

Dithiophosphinate complexes of the actinides. II. Preparation and characterisation of the compounds UO 2(S 2PR 2) 2 · R′OH,[Et 4N][UO 2(S 2PR 2) 2Cl] and UO 2(S 2PR 2) 2 · Me 3PO. The crystal structures of UO 2(S 2PR 2) 2 · EtOH, R = Ph and C 6H 11, [Et 4N] [UO 2(S 2PR 2) 2Cl], R =

Salts of dithiophosphinic acids, R 2PS 2H, react with UO 2Cl 2 in alcoholic, R′OH, solution to yield the complexes UO 2(S 2PR 2) 2 · R′OH. In the presence of excess chloride ion the alcohol is displaced to form the anionic chloro-complexes, which may be isolated as their [Et 4N] + salts. Similar reactions with UCl 4 in the air yield the same compounds in a novel double oxidation reaction. The initially formed U(IV) complexes are rapidly oxidised by the air to yield the corresponding uranyl compound and, at the same time, two ligands are oxidised to form the dimer, [R 2PS 2] 2. When [UCl 6] 2− is employed, only the chlorocomplexes are obtained. The complexes for R = Me, Et, Pr i, OMe, OEt, OPr i, Ph and C 6H 11 have been characterised by elemental analysis, IR and NMR spectroscopy. From one reaction of UVl 4 and NaS 2PMe 2, the complex UO 2(S 2PMe 2) 2 · Me 3PO was obtained by an unknown route. The crystal structures have been determined for two alcohol adducts, two chlorocomplexes and the phosphine oxide adduct. UO 2(S 2PPh 2) 2 · EtOH: Triclinic, a = 11.589(2), b = 11.6928(8), c = 13.273(2) Å, α = 113.205(8), β = 110. 849(9), γ = 92.979(9)°, P 1 , R = 0.057. UO 2{S 2P(C 6H 11) 2} 2 · EtOH: Monoclinic, a = 12.765(1), b = 16.502(2), c = 15.813(2) Å, β = 90.622(9)°, P2 1/n, R = 0.044. [Et 4N][UO 2(S 2PMe 2) 2Cl]: Orthorhombic, a = 10.770(1), b = 11.730(2), c = 20.079(2) Å, P2 12 12 1, R = 0.033. [Et 4N][UO 2(S 2PPh 2) 2Cl]: Monoclinic, a = 11.341 (2), b = 20.889(30, c = 16.172(2) Å, β = 101.79(1)°, P2 1/n, R = 0.046. UO 2(S 2PMe 2) 2 · Me 3PO: Orthorhombic, a = 11.499 910, b = 13.079(1), c = 14.362(1) Å, Pcmn, R = 0.050. All five complexes have pentagonal bipyramidal structures. The pentagonal plane contains four sulphur atoms from the two bidentate dithiophosphinate ligands (US = 2.873 Å) and one oxygen or chlorine atom from the coordinated ethanol (US = 2.41 Å), phosphine oxide (US = 2.32 Å) or chloride (US = 2.677 Å). The uranyl group is linear (US = 1.76 Å) and perpendicular to the equatorial plane. In both ethanol adducts the ethyl groups of the alcohol are disordered. The phosphine oxide adduct has crystallographic m symmetry. No more than two bidentate ligands could be attached to the uranium; however, a fifth equatorial coordination site is always occupied by an additional ligan, even when the substituents at phosphorus are bulky.

The infrared spectra (3500—150 cm-1) of aniline complexes of cobalt(II), nickel(II), copper(II) and zinc(II) halides

The IR spectra (3500—150 cm −1) of the complexes [M(aniline) 2,X 2 (M = Co, Ni, Cu, Zn; X = Cl, Br), [Zn(aniline) 2I 2] are discussed. Assignments of the internal ligand vibrations are based on the band shifts which result from 15N-labelling of the amino group. The metal—ligand stretching frequencies, ν(M—N) and ν(M—X), are assigned on the basis of the band shifts which occur on 15N-labelling and metal ion and halogen substitution. Two bands within the range 350–450 cm −1 are assigned to ν(M—N) while the ν(M—X) bands occur within the range 170–320 cm −1. The effects of structure and coordination number on ν(M—N) and ν(M—X) are discussed. The spectra of two ethanol adducts, [M(aniline) 2-(ethanol) 2Cl 2] (M = Co, Ni) compared with those of the unsolvated species [M(aniline) 2-Cl 2], exhibit a unique band near 480 cm −1 which is insensitive to 15N-labelling and is assigned to ν(M—O).

Structure of moreollin, a pigment isolated fromGarcinia morella Desser

The structure of moreollin (3), isolated from the seed coat ofG. morella, and its isomerised product, isomoreollin (4) have been established as the ethanol adducts of morellin (1) and isomorellin (2) on the basis of p.m.r., c.m.r., mass spectrometry and confirmed by partial synthesis from morellin (1) and isomorellin (2).

Crystal and molecular structures of {NN′-[2-(2′-pyridyl)ethyl]ethylenebis(salicylideneiminato)}-iron(II) and -cobalt(II)–ethanol (1/1)

The crystal and molecular structures of the title complexes, [Fe(salpeen)](1) and [Co(salpeen)]·EtOH (2), have been determined using three-dimensional X-ray diffraction data collected on automatic diffractometers. Complex (1) crystallises in the monoclinic space group P21/c with the unit-cell parameters a= 10.572(2), b= 11.465(2), c= 16.640(3)A, β= 90.52(1)°, and Z= 4, and its structure has been refined by conventional least-squares techniques using 1 118 reflections having I > 3σI to give R 0.056 and R′ 0.062. Complex (2) crystallises in the triclinic space group P with the unit-cell parameters a= 15.049(2), b= 15.127(2), c=10.258(1)A, α= 90.53(l), β= 93.53(1), γ= 109.81 (1)°, and Z= 4, and its structure has been refined using 1 237 reflections having I > 3σI to give R 0.064 and R′ 0.069. The cobalt complex thus has two crystallographically independent molecules in the asymmetric unit, each hydrogen bonded via an oxygen atom to an ethanol adduct molecule; there are small but significant differences between the two molecules. The iron and cobalt complexes have a similar distorted trigonal-bipyramidal geometry.

ChemInform Abstract: PHOTODIMERIZATION OF ETHYL 2‐ETHOXY‐1,2‐DIHYDROQUINOLINE 1‐CARBOXYLATE

Irradiation of ethyl 2-ethoxy-1, 2-dihydroquinoline-1-carboxylate (1) in ether and ethanol resulted in the formation of a trans head-to-head dimer 2 and an ethanol adduct 5 in 66 and 45% yields, respectively.

New proposal for structure of special-pair chlorophyll

A new model is proposed for the structure of the special pair of chlorophyll a molecules believed to correspond to the P700 species in green plants and algae. The proposed model, although admittedly speculative, is based upon exciton-theoretical considerations and on in vitro infrared and visible absorption spectra of a 700 nm absorbing ethanol adduct of chlorophyll a. In the new model, two chlorophyll a molecules are held together by (a) two strong ring V keto C[unk]O[unk]H[unk]O (or keto C[unk]O[unk]H[unk]N, or keto C[unk]O[unk]H[unk]S) hydrogen bonds and by (b) pi-pi van der Waals stacking interactions between the two chlorophyll a macrocycles. Macrocycle stacking provides the intermolecular pi-pi overlap necessary to promote the (experimentally observed) delocalization of the unpaired electron of the in vivo radical over two chlorophyll pi systems. The new model provides an explicit role for the participation of protein in the formation of the chlorophyll special pair. The in vitro system yields an electron spin resonance signal indistinguishable from that of oxidized P700 in Chlorella vulgaris.

Photodimerization of ethyl 2-ethoxy-1,2-dihydroquinoline-1-carboxylate.

Irradiation of ethyl 2-ethoxy-1, 2-dihydroquinoline-1-carboxylate (1) in ether and ethanol resulted in the formation of a trans head-to-head dimer 2 and an ethanol adduct 5 in 66 and 45% yields, respectively.

Crystal, molecular, and electronic structure of an antianxiety agent: 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-3-hydroxy-1,4-benzodiazepin-2-one

The crystal and molecular structure of the ethanol adduct, of the title compound has been performed, from three-dimensional X-ray counter data by use of the symbolic addition procedure, and refined by least-squares methods to R 0.066 for 2 024 observed reflections. Crystals are monoclinic, space group P21/n, with cell dimensions: a= 13.446(15), b= 19.259(9), c= 13.789(8)A, β= 116.80(7)°. The asymmetric unit consists of one ethanol and two benzodiazepine a molecules, linked together by hydrogen bonds. The heterocyclic seven-membered ring adopts a boat configuraion; the two phenyl rings are planar, the obtuse angles between them being 106.6 and 99.1°.

Kinetics and mechanism of the carboxylic acid catalysed ethanolysis of p-chlorophenyl isocyanate in diethyl ether

The kinetics of carboxylic acid catalysis of the ethanolysis of p-chlorophenyl isocyanate in diethyl ether at 25° have been investigated. The results suggest that an intermediate 1 : 1-acid–ethanol adduct is rapidly formed, and that this intermediate then attacks the isocyanate in a slow step. Equilibrium constants for intermediate formation and rate constants for its reaction with the isocyanate have been deduced. Whereas the values of the former are independent of the acid's strength, the latter are inversely dependent on it. It is argued that the intermediate has a cyclic structure, and that the probable mechanism of the slow step is a simultaneous attack by the intermediate on the carbon and nitrogen atoms of the isocyanate with the formation of a cyclic transition state. This mechanism is analogous to that for the corresponding reaction of ketens. The dimerisation of carboxylic acid catalysts and their interaction with ethanol in ether have been studied using i.r. spectroscopy.

Photochemical reactions of 1,2-dihydroquinolines

Irradiation of ethyl 2-substituted 1,2-dihydroquinoline-1-carboxylates gives rise to allenic compounds and ethanol adducts depending upon the solvent used; product formation is rationalised in terms of benzoazahexatriene intermediates.

Comments on the interaction of copper(II) chelates with chloroform as observed in the electron paramagnetic resonance spectra

Re-examination of the e.p.r. spectra of copper(II) bisacetylacetonate in chloroform–toluene glasses demonstrates that a recent suggestion, that chloroform interacts strongly with the chelate metal site, is incorrect. Solvent impurities are found responsible for the previously reported e.p.r. spectrum. The anisotropic e.p.r. parameters for copper(II) acetylacetonate and its ethanol adduct are reported.

Substituted benzoic acid complexes of copper(II)

Solutions of p-cyano, p-fluoro, p- and m-hydroxy-benzoic acids in ehtanol react with aqueous solutions of copper- (II) aceetate to yield complexes of empirical formula [Cu(X-C 6H 4CO 2)(OH)]. The use of similar reaction conditions for p-chloro-, p-bromo-and p-iodo-benzoic acids affords ethanol adducts of the corresponding copper benzoates, Cu(X-C 6H 4CO 2) 2.C 2H 5OH. The latter compounds display subnormal magnetic moments and antiferromagnetism similar to that noted for copper acetate monohydrate. The presence of analogous binuclear structural species is proposed. On the basis of the normal moments and infrared spectral evidence, it is suggested that the complexes containing hydroxy groups are composed of polymeric hydroxide-bridged structural units. The magnetic behavior of these derivatives has been related to previously experienced difficulties in correlating the magnetic susceptibilities of copper(II) salts of substituted benzoic acids with the substituents on the phenyl ring.

Perchloro-(dimethylene-1,2-cyclobutanedione) and Its Solvolytic Degradation

Abstract Perchloro-(3,4-dimethylenecyclobutene) has been converted to 1, 3′, 3′, 4′, 4′-pentachloro-2-methoxy-3,4-dimethylenecyclobutene; in some solutions exposed to the air, this then gradually decomposed to perchloro-(dimethylene-1, 2-cyclobutanedione). The further spontaneous degradation of the last compound in an aqueous ethanol solution has also been investigated in order to elucidate the structures of an unstable intermediate (an adduct of ethanol to the carbonyl) and the end product (the hemi-ketal lactone ester). The physical and chemical properties of these compounds have been given and discussed. A possible bicyclic intermediate caused by the interaction between the hydroxyl group and the diagonally-positioned dichloromethylene group in above unstable ethanol adduct has been suggested in the process from the latter compound to the end product.