摘要:

AbstractThe14N nuclear quadrupole resonance (NQR) spectra of several aminatedn‐alkanes of the type CH3(CH2)xNH2(CH2)xNH2at 77 K are reported and analysed in the framework of a semi‐empirical theory. The NQR data presented oscillations forx<6 and reached limiting values forx≥6. The results obtained are discussed in terms of inductive and conjugative effects, as well as the possible contributions of the hydrogen bond network presented in the solid

ISSN:0030-4921    

DOI:10.1002/omr.1270210112

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe carbonT1values of the alkyl substituents of various compounds have been measured. The salient observation is that the terminal methyl carbon of then‐propyl or a three‐carbon chain bonded to an electronegative atom X(or an electron‐donating group) has a reducedT1value. A net attractive interaction between the methyl hydrogen atoms and X in thegaucheconformation is invoked to account for the observed result. In chains longer than three carbons that are not firmly anchored at one end, the γ steric interaction is suggested to be the main steric interaction that causes the reducedT1value observed for the terminal methyl

ISSN:0030-4921    

DOI:10.1002/omr.1270210113

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe1H NMR spectra of themeso‐ and (±)‐forms of some 1,4‐disubstituted 2,3‐diphenylbutanes were measured at 400 MHz. The spectral parameters were determined by iterative computer analysis, treating the protons as ABXX′A′B′ or (in some cases) A2

ISSN:0030-4921    

DOI:10.1002/omr.1270210114

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractFrom differential spin decoupling and nuclear Overhauser enhancement experiments, the 400 MHz1H NMR spectrum of the triterpene 7β‐acetoxy‐22‐hydroxyhopane is interpreted to establish the α‐configuration of the side‐ch

ISSN:0030-4921    

DOI:10.1002/omr.1270210115

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe13C and1H NMR spectra of (–)‐bis[1R, 3R, 4S]menthylphosphine (1) are assigned by two‐dimensional double quantum NMR and13C1H shift correlation diagrams. The variable temperature spectra of 1 indicate hindered rotation about the P

ISSN:0030-4921    

DOI:10.1002/omr.1270210116

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe1H and13C NMR spectra of 3,3,‐diiodotetramethylpentane (2), 3,3‐dibromotetramethylpentane (3), and 3,3‐dichlorotetramethylpentane (4) are temperature dependent. The activation parameters for thetert‐butyl group rotation in 2–4 have been determined. The13C NMR chemical shifts are

ISSN:0030-4921    

DOI:10.1002/omr.1270210117

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe use of the water‐soluble reference materials sodium 2,2‐dimethylsilapentane sulphonate (DSS) and sodium 2,2,3,3,‐tetradeuterio‐3‐trimethysilyl propionate (TSP‐d4) as internal standards for the calibration of carbon spectra determined in D2O is proposed. Problems arising from the use of secondary or external references are eliminated; very high field spectra (13C at 100 MHz) may be calibrated

ISSN:0030-4921    

DOI:10.1002/omr.1270210118

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractThe13C NMR spectrum of 6H‐pyrido[4,3‐b]‐5,11‐dimethylcarbazole has been re‐examined to confirm the assignments using normal decoupled and coupled INEPT techniques. The results indicate that there were several errors in previous assignments.J(13C,1H) for the seven methine carbons have also been

ISSN:0030-4921    

DOI:10.1002/omr.1270210119

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

Abstract29Si chemical shifts are reported for nine 1,2‐bis(trimethylsiloxy)cycloalkenes and four 1‐trimethylsiloxycycloalkenes, (Me3SiO)xCnH2n–2–x(x=1, 2). For cycloalkene derivatives withn⩽8 the silicon shift exhibits a strong dependence on the ring size, although the silicon is exocyclic and is separated by two bonds from the olefinic carbon atom. The dependence can be exploited for ring size determination of cyclic ketones after trimethyls

ISSN:0030-4921    

DOI:10.1002/omr.1270210120

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY

摘要:

AbstractCarbon‐13 chemical shifts and the POC, POCC, PNC and PNCC coupling constants of 18 compounds containing the amine moiety, and with the general formula Y2P(X)NHR [Y=C2H5O, C6H5O, CH2O, Y2=1,2‐dioxybenzene; X = O or S; R = H, CH3, C2H5, PhCH2CH2, (CH3)2CH, C(CH3)3, C6H11, C6H5, C6H5NH] have been determined. The Y2P(X) group shows a sterically induced effect on the amine moiety; the13C chemical shift of the Y group is, however, almost unaffected on replacing P(O) by a P(S) gr

ISSN:0030-4921    

DOI:10.1002/omr.1270210121

出版商:John Wiley&Sons Limited    

年代:1983

数据来源: WILEY