Phenyl proton

At first, the dimeric nature of the base isolated from 3-ethyl-2-methyl-4-phenylthiazolium was postulated via a chemical route. Indeed the adduct of ICH, on a similar 2-ethylidene base is a 2-isopropylthiazolium salt in the case of methylene base it is an anilinovinyl compound identified by its absorption spectrum and chemical reactivity (45-47). This dimeric structure of the molecule has been definitively established by its NMR spectrum. It is very similar to the base issued from 2.3-dimethyl-benzo thiazolium (48). It corresponds to 2-(3 -ethyl-4 -phenyl-2 -methylenethiazolinilydene)2-methyl-3-ethyl-4-phenylthiazoline (13). There is only one methyl signal (62 = 2.59), and two series of signals (63= 1.36-3.90, 63= 1.12-3.78) correspond to ethyl groups. Three protons attributed to positions T,5,5 are shifted to a lower field 5.93, 6.58, and 8.36 ppm. The bulk of the ten phenyl protons is at 7.3 ppm (Scheme 22). 

The product has the following spectral properties infrared (KBr) cm.-1 3103 and 3006 (aromatic C—H), 2955, 2925, and 2830 (aliphatic C—H stretching), 1257 and 1032 (aromatic methyl ether), 841 and 812 (C—H out-of-plane bending of isoxazole C4—H and 4-substituted phenyl) proton magnetic resonance (trifluoroaeetic acid) 5, multiplicity, number of protons, assignment 3.98 (singlet,... 

Because of the symmetric structure, H NMR spectra of 12 show only two signals assignable to methyl and phenyl protons at S 0.50... 

Proton ENDOR. In both metal complexes four pairs of magnetically equivalent pyrrole protons along with some weakly coupled phenyl protons have been observed. 

This NOE idea was then extended to Pd(ii) allyl complexes with bidentate phosphine auxiliaries [99-111], with the ortho P-phenyl protons acting as the reporters (see 81). Figure 1.17 shows a section of the H, H NOESY for [Pd(P-pinene allyl) (Chiraphos)](OTf) (Chiraphos = Ph2PCH(CH3)CH(CH3)PPh2), 81 [129], and reveals the numerous contacts from the chiral phenyl array to the allyl ligand. 

Figure 1.17 Section ofthe H, H NOESY showing the contacts from the ortho P-phenyl protons to various p-pinene protons. Chiraphos = Ph2pCH(CH3)CH(CH3)PPh2.

The bidentate oxazoline ligands 85 and 86 (and derivatives thereof) are excellent reporter ligands, and several studies have used NOEs to determine the nature of their chiral pockets [61, 113, 114, 126]. NOESY studies on the cations [Ir(l,5-COD)(86)]+ and several cationic tri-nudear Ir(iii)(hydrido) compounds [110], e. g. [Ir3(p3-H)(H)5(86)3] +, 87, in connection with their hydrogenation activity, allowed their 3-D solution structures to be determined. In addition to the ortho P-phenyl protons, the protons of the oxazoline alkyl group are helpful in assigning the 3-D structure of both the catalyst precursors and the inactive tri-nudear dusters. Specifically, for one of these tri-nudear Ir(iii) complexes, 87 [110], with terminal hydride ligands at d -17.84 and d -21.32 (and a triply bridging hydride at 5 -7.07), the P-phenyl and oxazoline reporters define their relative positions, as shown in Scheme 1.5. 

Determination of relative configuration. Thus, if diastereomeric compounds form complexes with LSR, a number of nuclei differ in their relative orientation with respect to the lanthanide ion. A given nucleus in one diastereomer has different r and 8 values than the corresponding nucleus in the other so that a different LIS is experienced. Using this method, structures of diastereomers can be assigned. For example, the LIS of the phenyl protons is much larger in cw-l-cyclohexyl-2-phenyl-3-azetidinol than in the tram-iso-... 

Nuclear magnetic resonance spectra were also obtained for 2-terf-buty 1-3-phenyloxazirane (XVI) and 2- rf-butylox zirane (XVII).4 The former compound had three absorption peaks with chemical shifts, equal to +0.26 (phenyl protons). -0.01 (oxazirane proton) and —0.40 (fcrt-fnityl protons). In the latter oonjpound the... 

If an MU1 acetylaoetonate is used for the porphyrin metallation, Min(Por)(acac) is formed, in which the acetylacetonato coordinates to the metal as a bidentate ligand (Scheme 7).1703 The paramagnetic NMR shift of the phenyl proton in Euni(TPP)(acac) suggests a large displacement of the europium atom from the centre of the porphyrin ( 2.0 A) with long Eu—Np r bonds ( 2.83 A). Sandwich complexes Ce(TPP)2 and PrH(TTP)2 have been reported.34... 

The CH protons in the 4-position of both 2 and 7C shift to very low field they appear along with the phenyl proton multiplets in the region S 6.7-7.53 ppm. Likewise, the 4-phenyl protons in 7A and 7B lie in the same range as the N-phenyl protons, and multiplets at 6 7.3-7.93 ppm are obtained. 

The reaction of 3,4-benzo-l,2-disilacyclobutene (22) with Cgo yields the corresponding disilacyclohexane derivative (23)20. Irradiation of a solution of disilacyclobutene 22 and Cgo in toluene with a low-pressure mercury lamp (254 nm) afforded the brown adduct 23 in 14% yield (based on unreacted Cgo) (equation 8). The FAB mass spectrum of 23 exhibits one peak at m/z 1024-1027 (C7sH32Si2, M+, molecular cluster ion), as well as one for Cgo at m/z 720-723. The -NMR spectrum of 23 showed a symmetrical spectrum with two diastereotopic isopropyl methyl protons, one isopropyl methine proton and a AA BB pattern assigned to phenyl protons. The 13C-NMR spectrum of 23 shows 17 signals for the Cgo skeleton, of which four correspond to two carbon atoms each and 13 correspond to four carbon atoms each one signal appears at 63.93 ppm and the remainder between 130 and 160 ppm (Scheme 7, Figure 10). This pattern is consistent... 

Fig. 5.8. H NMR spectra of high spin Fe(lII) porphyrins. (A) Fe TPP-C1 (no substituent at the pyrrole positions). Signal a refers to pyrrole protons signals b, c and d refer to the meta, ortho and para phenyl protons respectively [19]. (B) Fe (protoporphyrin IX)-C1 (see Fig. 5.7A for the ligand). Signals a belong to the methyl groups, signals b and g to the 13,17 a-CH2 and the 3,8 a-CH signals d to the COOH signals e to the 13,17 P-CH2 signals h and i to the 3,8 P-CH cis and p-CH trans respectively [20].

Complex Temperature (K) Pyrrole-H Phenyl protons o-H m-H p-H CH3 Propyl protons a-CH2 P-CH2 Ethyl protons y-CHj a-CH2 P-CH3 Methyl protons 1 X... 

The proton spectrum of phenylacetic acid (C6H5 CH2 C02H Fig. 3.47) exhibits three absorptions in the ratio 1 2 5 due to the carboxylic acid, methylene and phenyl protons respectively. The carboxylic acid proton has been offset by... 

The prime indicates the meso-phenyl protons located on the same side of the axial ligand with respect to the macrocycle plane. d Deuteriated benzene solutions. 

In the case of BPA-PC (Fig. 25), two types of protons are present the methyl and phenyl protons. The temperature dependence of the H NMR line width [18] shows two distinct components between - 190 and - 150 °C (Fig. 35). The broader component is attributed to methyl protons and the other to phenyl protons. For the latter component a moderate narrowing is observed at about - 80 °C. 

The temperature dependence of AH2 for chloral-PC (Fig. 37) shows that the motions of phenyl rings occur above -80°C. Furthermore, the doublet shape observed for the lH spectrum above room temperature presents a splitting constant of 25 d= 0.2 G, which corresponds to the static interaction between the 2,3 phenyl protons, indicating that the phenyl motions do not affect the dipole-dipole interaction parallel to the 1,4 phenyl axis. A quantitative analysis of the intra- and inter molecular contributions to AH2 leads to the conclusion that the phenyl motions correspond to either isolated or concerted rotations around the 1,4 axis, with little (if any) reorientation of this axis. In addition, it excludes other motions as crankshaft motions, or motion of the phenyl-ethylenic unit as a group. The decrease of AH2 above - 40 °C could be intermolecular in nature. 

Another way of using JH NMR to study the dynamics of phenyl protons in BPA-PC consists in selective deuteration of the methyl groups (BPA-d6-PC) [32]. Thus, the temperature dependence of the JH spin-lattice relaxation time, Ti, and spin-lattice relaxation time in the rotating frame, T p, has been determined, and is shown in Fig. 38. 

Co-ozonolysis of /< r/-butylethene (3,3-dimethyl-l-butene) in the presence of benzoyl cyanide gave as major product (55%) 3-cyano-3-phenyl-l,2,4-trioxolane 103 along with 13% of the ft /t-butyl-substituted 1,2,4-trioxolanes 108 as a mixture of stereoisomers in 53 47 Z/E ratio which could be assigned from nuclear Overhauser effect (NOE) data, as only the (Z) compound shows an NOE enhancement (across the 1,2,4-trioxolane ring) of the ortho-phenyl protons upon irradiation of the Bu methyl groups (Equation (10) and Figure 5). 

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