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The long-range deuterium isotope effects on13C nuclear shielding are physically not yet completely understood. Two existing models for explaining these effects, vibrational and substituent, are compared here. The vibrational model is based on the Born-Oppenheimer approximation, but it can explain only one-bond deuterium effects. To the contrary, the substituent model may explain many long-range isotope effects, but it is controversial due to the assumption of some distinct electronic properties of isotopes. We explain how long-range deuterium isotope effects may be rationalized by the subtle electronic changes induced by isotope substitution, which does not violate the Born-Oppenheimer approximation.

The 1 delta, 2 delta, 3 delta, 4 delta and 5 delta deuterim isotope effects in carbon-13 chemical shifts were determined for five monodeuterated 2-adamantanone isotopomers (1-5) and for two dideuterated 2-adamantanone isotopomers(6, 7), as well as for the two monodeuterated adamantane isotopomers (8, 9) and for adamantane-2, 2-d2 (10).

A series of forty six fluorinated mono- and binuclear aromatic compounds have been investigated using 13C NMR spectroscopy. The extent, the mechanism and the conformational dependence of carbon fluorine long range couplings (l.r.c.) were determined. The longest CF interaction observed if the 10JCF found in trans-4-fluorostilbene. For conjugated molecules a correlation between 6JCF and the molecular dihedral angle was established on the basis of a simple π-electron conjugation model which follows the cos20 law. However, for the most CF couplings other mechanisms like σ-electron contributions, through-space interactions, effects of lone electron pairs etc. play significant roles as well.

The extent of divinylbenzene (DVB) grafting onto cellulose fabric increases with total gamma radiation dose up to 10 to 15 kGy while it decreases with the radiation dose rate. A quantitative analysis of DVB grafting has been attempted by means of IR spectroscopy using the baseline method. Characteristic bands were selected in the spectra of copolymers, namely, the cellulose band at 1160 cm/sup -1/ and DVB band at 798 cm/sup -1/. The former band decreased and the latter increased with the degree of copolymerization, and the values were in accordance with the calibration straight line. An attempt to graft DVB onto cotton fabric previously grafted with styrene showed greater extent of copolymerization than with pure fabric.

Infrared spectra in the range 4000-50 cm −1 and Raman spectra in the range 4000-20 cm −1 of powdered samples of trans -stilbene, nine partially deuterated trans -stilbenes, and perdeutero trans -stilbene were recorded. The assignment based on group vibrational concept and isotopic shifts for most fundamental vibrations of all eleven isotopic species is proposed and discussed. The comparison between in-phase and out-of-phase phenyl ring modes is made. The correspondence to vibrations of monosubstituted, o -, m -, and p -disubstituted benzenes as well as trans -1,2-disubstituted ethylenes is also discussed.

A planar model of trans-stilbene (tSB) for modified valence force field calculations was assumed. Twenty seven force constants were used to reproduce 245 solution wave numbers for in-plane vibrations of tSB, α, α′-D 2 -tSB, 2,3,4,5,6,2′,3′,4′,5′,6′-D 10 - −tSB and D 12 -tSB, as well as of four benzene isotopomers. The calculated force field reproduces well the ring vibrations and potential energy distribution indicates the couplings of ring and ethylenic vibrations. For a more reliable assignment vibrational data from other tSB isotopomers should be taken into account.

Infrared and Raman spectra of trans-α-fluoro-stilbene, trans-α,α′-difluoro-stilbene, trans-4,4′-difluoro-stilbene and trans-2,2′,3,3′,4,4′,5,5′,6,6′-decafluoro-stilbene were recorded and are reported here for the first time. The assignments are proposed for nearly all fundamental vibrations in the solid state and are compared with the assignments for the partially deuterated trans-stilbenes.

The coupling reactions of diazonium chlorides with sym- 1,3,5-triketones are described. The azo-form of the products · is rearranged .into .the hydrazo-form during this reaction. Dihydrazones (I) were formed in the sodiumacetate buffered so1ution while in the sodium hydroxide solution both (I) and monohydrazones (II) were formed. The spectroscopic analysis, based on the data from infrared and ultraviolet spectra, indicates that dihydrazones exist in the double syn-form with an intramolecular hydrogen bond.

The construction ,of a th ermostated liquid infrared cell for the temperature range from -1ooc to gooc is described. 'The cell is designed specifically for the P erkin-Elmer 21 series of double beam infrared spectrophotometers (Perkin-Elmer 21, 221 , 421 and 521), and can be conveniently used for kinetic studies.

Far infrared spectra of the molecules CH3HgBr, CH3Hgl, CDaHgBr and CD3Hgl in the range 350-59 cm-1 are presented. The results include vibrational frequencies of Hg-Hal stretching (v4) and C-Hg-Hal bending (v8) modes. The band shapes are consistent with shapes of other fundamental bands of methyl mercuric halides.

A quantitative powder-x-ray analysis was developed for this case by which it was shown that carefully prepared borax dehydrates directly into an unhydrous amorphous phase. Eight molecul es of water are quantitatively lost on complete dehydration (below 50°C) as required by the structural formula.. The proton m agnetic resonance results agree with these findings showing also that the spectrum due to OH-groups changes considerably on dehydration. This was used ~n following deuteration (solid/gas) of dehydrated borax. The p.m.r. spectra, the x-ray di agrams, and the measured regain indicate ·a reconshltution of the borax- lattice towards the formula Na2,[B 40 5(0H) 4] • 8D 20 .

The antitumor agent cis PtII(NH3)2Cl2 is known to interact with guanine with possible binding to the 6-oxo group, promoting deprotonation on N(1) [1]. N(4)O(7)Cu(II)-ribavirin chelate has been demonstrated [2] in a solid state and these particular binding sites were assumed also for other ribavirin-Me(II) interactions in solution. Even a single crystal-X-ray analysis assumed a conformation of ribavirin strikingly similar to guanosine [2]. This resemblance prompted further studies of ribavirin Pt(II) complexes as Pt(II) complexes are convenient to compare solid state and solution properties of these chelates. The binding of the paramagnetic Cu++ ion to rabavirin in solution was located mainly on N(5) by 1H and 13C line broadening and T1 relaxation times and did not support any binding on exocyclic oxygen O(7). The role of the carboxamide group in metal binding to ribavirin is thus not completely clear. Pt(II)-complexing will be discussed in order to clarify this question, as well as 14 relaxation of the carboxamide nitrogen. In this case, the indirect measurement of 14N relaxation rates is possible.T1ϱ (spin-locking method) eliminates effects on proton relaxation other than proton-nitrogen scalar coupling. Thus and T1N and A (4N-coupling) of amino protons will be evaluated from the following equation

The infra-red and Raman spectra of CH3HgBr and CD3HgBr are reported. Force constants have been calculated on the basis of an almost complete force field which was arrived at by systematic modifications of an approximate field using the Jacobian matrix. All the constants which significantly affect the calculated frequencies have been taken into account; the calculated force field is consistent with the hybrid orbital force field, which has not been assumed, although further refinements are necessary if a more detailed comparision is expected.