摘要:

The recent development of techniques in this and other laboratories has allowed the exploration of elemental mercury oxidations by compounds bearing the —O—O—H moiety. The peracid group appears to be a far more effective oxidant of mercury than the peroxide group, and both peracetic acid andm-chloroperbenzoic acid oxidize mercury at the trace level to both mercurous and mercuric forms.

ISSN:0008-4042    

DOI:10.1139/v85-045

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The dipole moment derivatives up to the fourth order are determined for the12C16O2molecule by fitting the experimental values of several transition intensities. The convergence is fast, but the third order is significant in order to obtain an acceptable accuracy (~20%).

ISSN:0008-4042    

DOI:10.1139/v85-046

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The gas phase ion molecule reactions of a number of anions, X−, with diborane, B2H6have been investigated using ion cyclotron resonance spectroscopy. Two distinct reaction channels are observed in addition to simple proton transfer. The first of these is production of BH4−and BH2X while the second is formation of BH3X−and BH3. In order to determine the importance of thermodynamic factors in the course of reactionabinitiocalculations have been carried out on the species involved to obtain the relative stabilities of the two possible pairs of products. The 4-31 +G basis set incorporating additional flatsandpfunctions has been used since this basis set has been demonstrated to give the most accurate description of anions to date. The results obtained indicate that the thermochemical factors are instrumental in determining the reaction pathway.

ISSN:0008-4042    

DOI:10.1139/v85-047

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

A selective methylation towards N and O atoms on aminoalcohols was observed using metal hydride reagents as the base, and the predominant factors for the selectivity were investigated in detail.

ISSN:0008-4042    

DOI:10.1139/v85-048

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

Vanadium tetrachloride-catalyzed dimerization of 3,5-dimethoxyphenol yields the key intermediate 2,2′,6,6′-tetra-methoxy-4,4′-dihydroxybiphenyl, from which the octamethyl ether of the brown algal metabolite "fucophlorethol A" (2,2′,4,6,6′-pentamethoxy-4′-(2,4,6-trimethoxyphenoxy)biphenyl,6) is synthesized by Ullmann condensation and Hakomori methylation.

ISSN:0008-4042    

DOI:10.1139/v85-049

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The high-molecular-weight polyphloroglucinol tannin ofFucusvesiculosushas been islated in pure form as judged by1H and13C nmr. Acetate and methyl derivatives were prepared and examined by uv and ir spectroscopy. Calcium – liquid ammonia degradation of the methyl ether derivative liberated numerous aryl compounds including fragments arising from ether-linked phloroglucinol end groups, internalortho-,meta-, andpara-oriented diethers,vic- and (tentatively identified)sym-triethers, internal phloroglucinol-derived biphenyls (three isomers), probable terminal biphenyls, terphenyl(s), and from qua-terphenyl(s). No evidence was found forvic-trihydroxylated end groups. In all, 63 fragments were identified by gc–ms, and abundances of the major fragments were estimated by quantitative gc. The data indicate that theF.vesiculosustannins – or at least the portion represented by these fragments – are highly branched structures consisting entirely of phloroglucinol units.

ISSN:0008-4042    

DOI:10.1139/v85-050

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

1H and13C nuclear magnetic resonance spectroscopy of the high-molecular-weight (> 104) polyphenol fraction fromFucusvesiculosus, before and after acetylation or methylation, demonstrates that it is composed of phloroglucinol units (48.9 ± 3.5%) and 2,2′,4,4′,6,6′-hexahydroxybiphenyl, 2,2′,2″,4,4′,4″,6,6′,6″-nonahydroxy-1,1′:3′1″-terphenyl, and related quater-and polyphenyl groups (together, 51.1 ± 3.5%) linked by ether bonds, each bond involving the carbinol and methine carbons of different units and the formal loss of a molecule of hydrogen. The polymer is highly branched, with ca. 20 – 22% of the constituent units being chain termini; there is no evidence for large rings of units. Approximately 5 – 10% of the phloroglucinol and 54 – 82% of the directly bonded units occur on the exterior of the molecule, whereas the interior backbone consists predominantly of ether-linked phloroglucinol units.

ISSN:0008-4042    

DOI:10.1139/v85-051

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

The ligand (MeNPMe)4(L) forms complexesL.M(CO)3(M = Cr, Mo, W, Mn+), and a nickel complex L.Ni2(CO)3, which is easily oxidised to the phosphonimide [MeNP(0)Me]4. Quaternary complexes [LM(CO)3R]+I−have been prepared both by quaternisation of the neutral complex (R = Me, CH2CN, CH2C(O)NH2, M = Cr, Mo, W) and (R = Me) by reaction of the simple quaternary with the metal carbonyl. The quaternary complexes have been deprotonated to ylidic complexes, L.M(CO)3CH2(M = Mo, W) in which the ylidic group has displaced one phosphine function. Chemical and structural features are discussed in terms ofd-orbital contraction by acceptor groups. The phosphazane (MeNPPh)4has been prepared.

ISSN:0008-4042    

DOI:10.1139/v85-052

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

As a result of an investigation undertaken to evaluate the acetamidomethyl group (—CH2NHCOCH3) as a water-solubilizing protecting group for thiolate ligands, a new type of oxotechnetium(V) complex was prepared. The compound oxobis(ethan-1,2-dithiolato-S,µS′)technetium(V)oxo(ethan-1,2-dithiolato-S,S′)technetium(V), [(TcO)2(SCH2CH2S)3],1, was synthesized by the reaction of [TcOCl4]−with either an excess of bis(acetamidomethyl)ethanedithiol or 1.5 equiv. of ethanedithiol. The complex was characterized by field desorption mass spectrometry (m/e = 505(8), 507(2.8)) and its structure determined by single crystal X-ray diffraction.1has a monoclinic space groupP21/cwith cell dimensionsa = 8.833(2) Å,b = 15,034(3) Å,c = 11.350(2) Å, and β = 108.17(1)°, and has four formula units in the unit cell. Data were collected with the use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structure was determined by standard methods and refined toR1 = 0.0366 andR2 = 0.0455 on the basis of 3312 independent reflections. The compound contains two technetium atoms. Two sulphur atoms of one square pyramidal TcOS4core are bonded to another TcOS2unit forming two square pyramids sharing an edge with an angle of 106.0(1) between the basal planes. TheTc—Tc distance is 3.654(1) Å. There are four distinct types of Tc—S bonds (range 2.256(2)—2.418(2) Å) and the Tc—O distances (1.66 Å) are normal.

ISSN:0008-4042    

DOI:10.1139/v85-053

出版商:NRC Research Press    

年代:1985

数据来源: NRC

摘要:

Order–disorder transitions occurring in the Ag2SO4–K2SO4system were investigated by reaction kinetics, thermal analyses, X-ray diffraction, and electrical conductivity techniques. Solid–liquid and solid–solid phase diagrams are reported.The conductivity data in the high temperature phase of the solid resemble superionic conductivity behavior. The higher conductivity of Ag2SO4with K+presence relative to pure Ag2SO4and Ag2−xNaxSO4compositions support a lattice expansion facilitating higher mobility of ions.The reaction kinetics, X-ray diffraction, and electroconductivity results suggest a relatively open periodicsublattice in the high-temperature phase of the sulfate-based systems studied in this series.

ISSN:0008-4042    

DOI:10.1139/v85-054

出版商:NRC Research Press    

年代:1985

数据来源: NRC