Dipole moment, measurement

In dioxane solution at 30°C, content of IH tautomer is 60 10% according to dipole moment measurements (80JHC1373). 

Electric dipole moment measurements on R3SiCo(CO)4, (R3Si)2Fe(CO)4, and related compounds have indicated a relationship between v(CO) and charge transfer in the Si—M bond within a given series the central transition metal is apparently not charged 156). Application of the relationship to HjSiCo(CO)4 suggests a small bond dipole in the sense... 

Conformation problems in five- and six-membered rings containing phosphorus continue to attract attention and, using n.m.r., i.r., and dipole-moment measurements, studies have been reported on 1,3,2-dioxaphospholan systems (118), > 1,3,2-dioxaphosphorinane systems... 

The geminal coupling of some azo1ooxaphospho1enes is reported to correlate with A.. 9 1 Vicinal couplings have been used in the conformational analysis of a variety of compounds such as dioxaphosphorinanes,92 phosphorinanes (in combination uith CNDO/2 calculations),93 and bromophosphorinanes (in combination uith dipole moment measurements).99 The various couplings for 1,1-viny1idene-diphosphonic acid and its salts have also been measured.95... 

Projection theorem, electric dipole moment measurement, 244—245 P,T-odd interactions ... 

Of special interest (see Table II) is the structure of compound XVI, obtained in a reaction with thermodynamic control, and its sulfide (XVII), as both molecules contain the P—H bond. Infrared, Raman, and NMR studies as well as dipole moment measurements showed that the P—H bond was axial in these compounds. In some cases the conclusions of NMR and dipole moment studies were verified by X-ray single-crystal analysis. 

In this next section the dipole magnitude and directionality from MM3(2000) is compared to results obtained by MM3(96), Hartree-Fock and Mdller-Plesset minimized structures (calculated using GAUSSIAN94),77 as well as experimental dipole moment measurements.78 For the molecular mechanics geometry optimizations, full matrix energy minimizations were carried out, and ground state structures were verified by the vibrational... 

Magnetic susceptibility measurements have been made for the lanthanide complexes of 2,6-DMePyO (171), EPO, BPO, EAsO, BAsO (237, 238), and AAP (95). In all these cases, the measured magnetic susceptibilities agree with the free ion values. Dipole moment measurements have been carried out on complexes of the type Ln(TBP)3-(N03)3 (387, 388). ESR studies on Gd(AP)6 I3 (389) and thermal decomposition studies on the complexes of the lanthanides with DMSO (250), DPSO (250, 259), QNO (175), HOQNO (190), 18-crown-6 (132), 15-crown-5 (131), and gycine (390) have also been reported. 

X-ray analysis of 4,4-dimethylandrostan-3-on-17/3-yl benzoate (67) that the A ring is in a deformed chair conformation (225) in the crystal, and NMR and dipole moment measurements show the same to be true in solution. 

The dipole moment measurement of scandium and europium complexes in solution showed the complexes to be planar. In the solid state, the values of metal atoms are squeezed out of... 

As a semirigid model (77JCP2874), quantum-chemical AMI and PM3 calculations (90JST179), and many NMR studies (to be discussed later) claim the chair conformation to be also that preferred for 1,4-dioxane. From dipole moment measurements, the participation of the boat conformer was suggested (76BSF1649, 76CR11 77CR869). 

This contradicts rules (i). However, in dioxan, an investigation based on dipole moment measurements concluded the predominance of 424b. In... 

Dipole moment measurements of solutions of cis- (64BSF2119 65JCS571) and tru/ii-thianthrene 5,10-dioxide (65JCS571) and of thianthrene 5,5,10,10-tetroxide (65JCS57I) gave values of 1.86 and 1.70, 4.88, and 5.11 D, from which fold angles of 139°, 130°, and 140° respectively, were calculated. 

Using a combination of techniques 1,3,4-thiadiazole was shown to have a dipole moment of 3.0 D directed from the sulfur atom toward the center of the N—N bond. Dipole moment measurements were useful for proving the mesoionic structure and the large negative charge of an exocyclic sulfur atom for certain 1,3,4-thiadiazole derivatives <84CheC-I(4)545>. 

Halogenated thietanes have been studied by Kumakura and Kodoma. Unusually large bond moments for the Cj—Cl bond were indicated from dipole moment measurements. X-Ray studies revealed a difference in C2—S and C4—S bond lengths, the latter being 0.008 A shorter than the former. 

Another useful technique has involved the use of IR spectra, and here the presence of amino and carbonyl stretching frequencies for 2- and 4-pyridinones and 2- and 4-quin-olinones suggest the predominance of the oxo tautomer, certainly in inert solvents (57JCS4874). These conclusions were supported by dipole moment measurements on 4-pyridinone and its model compounds in dioxane (56JCS1294), and by NMR measurements in aqueous solution (60CI(L)870). 

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