摘要:

The ultraviolet absorption and phosphorescence emission spectra of 2-(2-methylbenzoyl) thiophene (1), 2-benzoyl-3-methylthiophene (2), 2-benzoyl-4-methylthiophene (3), and 2-benzoyl-5-methylthiophene (4) are reported and analyzed. Partial energy diagrams are constructed. The lowest triplet is assigned as a π,π*state of the 2-thienoyl chromophore in every case. Photocycloaddition of isobutylene to the carbonyl group was observed with1and2. The oxetanes are thermally unstable; olefins 1-(2-thienyl)-1-(2-methylphenyl)-2-methylpropene (from1) and 1-phenyl-1-(2-(3-methylthienyl))-2-methylpropene (from2) were formed and characterized. Irradiation of1and2inO-deuteromethanol did not lead to incorporation of deuterium; no reaction was observed. These results are discussed in terms of the existing generalizations potentially useful for predicting photochemical reactivity.

ISSN:0008-4042    

DOI:10.1139/v75-001

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The possibility of forming spinel-type ferrites MFe2O4from M(OH)2or MO and α-FeO(OH) (goethite) or α-Fe2O3(hematite) under hydrothermal conditions up to 350° has been investigated experimentally for M = Mg, Ca, Mn, Co, Ni, Cu, and Zn. Formation of MFe2O4was observed for M = Mn (jacobsite), Co, Ni (trevorite), and Zn (franklinite), and was in general favored by high temperatures, high pH, and the presence of NaNO3or, especially, NaCl in solution. α-FeO(OH) is more reactive than α-Fe2O3, but generally converts to the latter at 220–260°, independently of pH, in neutral or alkaline media. Interpretation of the results is complicated by the ion-exchanging properties and varying degrees of crystallinity of M(OH)2, and by the tendency of M(OH)2to decompose to MO or to be oxidized at the higher temperatures. Nevertheless, the order of reactivity M = Co ≥ Mn > Ni > Zn > (Mg, Ca, Cu) in MFe2O4formation is generally valid. The formation of MFe2O4is limited by kinetic rather than thermodynamic factors for the various M listed (except Cu).

ISSN:0008-4042    

DOI:10.1139/v75-002

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Structures are assigned to seven minor products (6b,9,11b,12b,13b,16, and25b) obtained from treatment of methylent-trachyloban-19-oate (1) with thallic oxide in acetic acid. The mechanism of the oxidative cleavage is discussed. Formation of the major products, described earlier, and all but one (25b) of the minor products may be rationalized in terms of initial scission of the C13—C16bond.

ISSN:0008-4042    

DOI:10.1139/v75-003

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Methylexo-2-bromo-1-norobornanecarboxylate-endo,endo-5,6-d2(1b) has been prepared and solvolyzed at 112° in 80:20 EtOH-H2O buffered with NaOAc. The loss of 85–90% of the deuterium available on the front face of1bin the formation of the tricyclic ester 6D coupled with a novel analysis established that theendo:exopreference for 1,3 elimination is at least 15:1 to 20:1. A comparison of the solvolytic kinetic isotope effect (1.18 ± 0.04) for1band the 1,3-elimination kinetic isotope effect (1.45–1.6) with data for 1,2 eliminations indicates that elimination occurs from the classical, perhaps 1,3 hyperconjugatively stabilized carbocation20. Theendo:exopreference established in this study is used to reinterpret 1,3-elimination data determined by Collins in the solvolysis of deuteriohydroxyphenyl norbornyl tosylates.

ISSN:0008-4042    

DOI:10.1139/v75-004

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

InLycopodiumtristachyumlycopodine is derived fromL-lysine whereas pipecolic acid is derived fromD-lysine. Malonic acid serves as a specific precurser of the non-lysine derived segments of lycopodine. Piperidine-2-acetic acid is not incorporated into the alkaloid.

ISSN:0008-4042    

DOI:10.1139/v75-005

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Infrared spectra of M2[FeCl5(H2O)] (M = K, Rb, NH4) at different degrees of deuteration were recorded, between 4000 and 300 cm−1, at 30 and −160 °C. The spectra of the three compounds were closely similar, as was that of natural K2[FeCl5(H2O)] (erythrosiderite). They indicate the existence of only one type of water molecule in the structure. The water molecules are symmetric, well separated from one another, and engage in O—H … Cl bonds with O … Cl distances of about 3.22 Å, as estimated from the OH and OD stretching frequencies. These conclusions support the structure proposed for K2[FeCl5(H2O)] by Bellanca and lead to approximate location of the H atoms. The observed mixing of the librational and translational modes, which occurs when the frequencies of translational modes are high, may be characteristic of H2O molecules coordinated to cations of high charge.

ISSN:0008-4042    

DOI:10.1139/v75-006

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Crystals of theN,N-dimethylethanolaminogallane dimer1aare monoclinic,a = 8.540(1),b = 7.0433(7),c = 12.227(6) Å, β = 92.94(3)°,Z = 2, space groupP21/cand crystals of theN,N-dimethylethanolaminogallium dimethyl dimer1bare orthorhombic,a = 15.608(3),b = 11.655(2),c = 10.266(2) Å,Z = 4, space groupPccn. Both structures were determined by Patterson and Fourier syntheses and were refined by full-matrix least-squares procedures to finalRvalues of 0.039 and 0.053 for 1062 and 1155 reflections with1 ≥ 3σ(I) respectively. Both structures feature well-separated centrosymmetric dimeric units occurring via the formation of four-membered Ga2O2rings. The five-coordinate gallium atoms have distorted trigonal bipyramidal geometry. Steric interactions between methyl groups in1bare believed responsible for the lengthening of the axial Ga—N distance from 2.279(3) in1ato 2.471(4) Å in1b. Other bond distances are: for1a; Ga—O (axial), 2.053(3), Ga—O, 1.911(3), Ga—H, 1.50(7) and 1.73(5), O—C, 1.369(5), N—C, 1.466 – 1.485(6), C—C, 1.512(7), and mean C—H, 1.05; for1b; Ga—O (axial), 2.078(3), Ga—O, 1.913(3), Ga—C, 1.936(6) and 1.948(7), O—C, 1.382(7), N—C, 1.452–1.482(7−8), C—C, 1.516(9), and mean C—H, 1.01 Å.

ISSN:0008-4042    

DOI:10.1139/v75-007

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The synthesis and pyrolysis of the methyl phthalate esters of diphenylmethylsilyl,t-butylsilyl, benzyldiphenylsilyl, and optically active 2-octanol yielded corresponding silyl ethers and phthalic anhydride. In the case of the latter compound, almost complete retention of configuration was observed about the asymmetric carbon atom. A mechanism is proposed for this rearrangement.

ISSN:0008-4042    

DOI:10.1139/v75-008

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

This paper presents the far-infrared spectrum and X-ray powder diffraction pattern of the structure I hydrate of cyclopropane at 100 °K, and the powder diffraction pattern of the isostructural ethylene oxide hydrate at 100 °K. Between 360 and 100 cm−1the absorption by cyclopropane hydrate is essentially identical to that by ethylene oxide hydrate, but is shifted to low frequency by about 2%. This shift is undoubtedly related to the hydrogen bonds being slightly longer in cyclopropane hydrate, whose cubic lattice parameter is 11.98 ± 0.02 Å compared to 11.89 ± 0.02 Å for ethylene oxide hydrate, both at 110 ± 20 °K. The absorption by cyclopropane hydrate below 100 cm−1decreases rapidly with decreasing frequency; this confirms that the absorption plateau observed for ethylene oxide hydrate between 100 and about 50 cm−1is due to primarily rotational vibrations of ethylene oxide. A recent statement, that the orientational disorder of the water molecules need not be invoked to explain the far infrared spectrum of ice 1 h, is disputed.

ISSN:0008-4042    

DOI:10.1139/v75-009

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Electrochemiluminescence (e.c.1.) of mixed phenanthrene(Ph)-d10-oxidant and Ph-h10-oxidant systems have been studied. Emission from excited singlet state of Ph-d10or Ph-h10is observed. On the basis of energetics of the electron transfer reaction, triplet-triplet annihilation is postulated to give the excited singlet state of Ph. Comparison of these results with photoluminescence of Ph-d10, shows efficient triplet–triplet annihilation occurs in e.c.1.

ISSN:0008-4042    

DOI:10.1139/v75-010

出版商:NRC Research Press    

年代:1975

数据来源: NRC