摘要:

AbstractAdsorption of CO and CO2has been studied on zeolite Y in which Na+ions have been partially exchanged for Ca2+ions. Physisorption of CO and CO2provides a sensitive method for the observation of the population of Na+and Ca2+ions in supercage positions. The results indicate that Ca2+ions introduced into a NaY zeolite by aqueous ion exchange preferentially enter sites in the small cavities on subsequent dehydration. When the degree of Ca2+exchange stays below 35%, all the Na+ions initially present in the small cavities as well as the incoming Ca2+ions seem to remain inaccessible for CO and CO2molecules.However, a Na+replacement of 35 to 45% leaves the Ca2+ions unaffected by CO and CO2but causes an important migration of inaccessible Na+ions to accessible supercage positions. Further exchange (>45%) results in Ca2+ions occupying locations exposed to the supercages. This work establishes that CO and CO2are very sensitive probe molecules for investigating the location of unshielded mono‐ and divalent cations in zeolite

ISSN:0165-0513    

DOI:10.1002/recl.19770960502

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractCu(II), Ni(II) and Pd(II) complexes of the terdentate ligands 1‐(2‐pyridylmethylene)biuret and 1‐(2‐hydroxylphenyl)biuret (abrv. as pybiH2and phHbiH2, respectively) have been prepared and their spectral, magnetic and voltammetric properties studied. In a square‐planar coordination the metals are bonded to the pyridine N (in the pybi compounds) or to the phenolato O (in the phHbiH2compounds) and to one or two deprotonated amide N's in [Cu(pybiH)(H2O)]+, Pd(pybiH)Cl and [Cu(phbiH)]2respectively in Cu(pybi)(H2O) and [Ni(pybi)(OH)]−Comparison with other biuretato complexes of Cu reveals that increasing the number of coordinated amide N's goes parallel with increasing energy of the spectralddtransition and with a decrease of half wave potentials for the oxidation to Cu(III) as well as for the reduction to Cu(I) compounds. The redox orbitals seems to be located mainly on the metal centre in accord with previous MO

ISSN:0165-0513    

DOI:10.1002/recl.19770960503

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe reduction of the oxo functions in ethyl 5‐(6‐ethoxycarbonylhexyl)‐3,3‐dimethyl‐2,4‐dioxocyclopentanecarboxylate (1) with NaBH4, with LiAlH(O‐t‐Bu)3and by catalytic hydrogenation is described. Four isomeric hydroxycyclopentanones and four isomeric cyclopentanediols were isolated and their stereochemistry was determined, providing1H‐NMR and13C‐NMR data which should be useful in structural assignment of isomeric pros

ISSN:0165-0513    

DOI:10.1002/recl.19770960504

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe mechanism of the electrochemical reduction of nitrite has been studied at a rotating ring‐disc electrode. It is found that the reduction of nitrite to nitric oxide is a reversible process. The reduction of nitric oxide to hydroxylamine involves the intermediate HNO, from which dinitrogen oxide can be formed in a side reaction to the reduction proces

ISSN:0165-0513    

DOI:10.1002/recl.19770960505

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe complex tris(2,4‐pentanedionato)cobalt(III) shows a base‐catalysed solvolysis reaction both in alkaline solution and in liquid ammonia. Activation parameters of the reaction in alkaline solution and in liquid ammonia are discussed and compared. A preliminary proposal for a mechanism involving pre‐dissociation of the acidic proton on the ligand is disc

ISSN:0165-0513    

DOI:10.1002/recl.19770960506

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractA new and simple method for the conversion of the highly substituted arenedithiocarboxylates1a‐dinto the corresponding sulfines (thione oxides)3a‐dby chlorination and subsequent hydrolysis is described.The geometrical isomers of these sulfines are formed in the ratio 1:1. An excessive chlorination of the unhindered dithioesters1e‐iresults in (α,α‐dichloroaryl) sulfenyl chlorides 4, which can be converted into either thiobenzoyl chlorides by treatment with triphenylphosphine, or chlorosulfines by reaction with water and pyridine. Also an improved preparation of dichlorosulfine is

ISSN:0165-0513    

DOI:10.1002/recl.19770960507

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe Beckmann rearrangement of aldoximes catalyzed by transition metal salts proceeds by a dehydration‐hydration reaction. A mechanism is proposed in which nitrile is bound to an oxime‐metal complex; subsequently, water (as OH−and H+) is transferred from oxime to nitrile in the ligand sphere of the metal, yielding nitrile and amide, respect

ISSN:0165-0513    

DOI:10.1002/recl.19770960508

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractTosyl cyanide reacts smoothly with norbornadiene to form a nortricyclene‐derived tetracyclic lactam (4) by a [2 + 2 + 2]‐cycloaddition (Homo‐Diels‐Alder reaction), and two other nortricyclene derivatives by homo‐conjugate 1,4‐addition reactions. The structure and stereochemistry of the reaction products4, 5and 6 are fully elucidated by1H and13C NMR s

ISSN:0165-0513    

DOI:10.1002/recl.19770960509

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractThe preparation of 2‐chloro‐, 2‐bromo‐ and 2‐iodo‐3,5‐di‐tert‐butylbenzoic acid is described and a possible explanation for their unexpectedly high dissociation c

ISSN:0165-0513    

DOI:10.1002/recl.19770960510

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19770960501

出版商:WILEY‐VCH Verlag    

年代:1977

数据来源: WILEY