Aromatic leady(IV) compounds XIII. 13C FT-NMR investigations on alkylphenyllead(IV) compounds

Synthesis and Multinuclear NMR Properties of Sixmembered Heterocyclic Organolead Compounds

“…Experimental details on the recording and assignments of the various spectra have been published elsewhere [24,36]. 207 Pb NMR spectra were recorded on a Bruker WH 90 multinuclear spectrometer.…”

“…These findings are in agreement with the substituent chemical shift parameters found in the 13 C NMR spectroscopy of compounds of the type Ar.Pb [21,22], The chemical shift values of the sixmembered ring compounds in which Ε = CH 2 are in reasonable agreement with those of (o-CH 3 C 6 H 5 ) 4 Pb, while the 6( 13 C) values of the phenoxaplumbin compounds (E = O) can be compared with those of (o-CH 3 OC 6 H 4 ) 4 Pb [22], As might be expected, with a particular hetero atom Ε the J( 207 Pb-13 Q values appear to depend on the nature of the substituent R on the lead atom. In view of the Fermi contact term which dominates the coupling constants in which heavy metals such as lead are involved [23], variations in the values of 1 J( 207 Pb-13 C) can be explained on the basis of variations of the nuclear charge and/or the hybridisation of the atoms participating in the coupling mechanism [24], The variations in the 1 J(^0 7 Pb-13 C) values with the substituent R might be described by a "polar group effect", affecting hybridisation and nuclear s-electron density [25,26]. In view of the Fermi contact term which dominates the coupling constants in which heavy metals such as lead are involved [23], variations in the values of 1 J( 207 Pb-13 C) can be explained on the basis of variations of the nuclear charge and/or the hybridisation of the atoms participating in the coupling mechanism [24], The variations in the 1 J(^0 7 Pb-13 C) values with the substituent R might be described by a "polar group effect", affecting hybridisation and nuclear s-electron density [25,26].…”

“…Illustrative data are summarized in Table IV. it is known that for the absolute magnitudes of the lead-carbon coupling constants the relationship l 1 JI»l 3 JI>l 2 JI holds [24,25]. when R = C 6 H 5 from 1924 for η = 0 to 1832 Hz for η = 2).…”

ortho-Arylation of 3,5-di-tert-butylphenol with aryllead(IV) derivatives: a facile synthesis of sterically hindered phenols

“…When the reaction was repeated using 4 equiv. of lead reagent 13 at room temperature and the homogeneity of the reaction restored by the addition of a further cm3 of chloroform after 24 h and the resultant solution stirred for another 24 h, an 87% yield of diarylated phenol 16 was obtained. These conditions were considered the optimal phenol arylation conditions and they ought to be general for a range of aryllead triacetates.…”

Über gemischte Bindungen in der IV. Hauptgruppe, II [1]. Hexacyclohexylethan-Analoga Pb2(c-Hex)6, (c-Hex)3Pb–Sn(c-Hex)3 und Sn2(c-Hex)6 / On Mixed Group IVb – Group IVb Bonds, II [1]. Hexacyclohexylethane Analogues Pb2(c-Hex)6, (c-Hex)3Pb–Sn(c-Hex)3, and Sn2(c-Hex)6

“…II enthält 13 C-NMR-Daten für die drei dinuclearen Verbindungen, zwei mononucleare Verbindungen mit M(c-Hex) 3 -Gruppierung und zwei Literaturverbindungen [8,9] wirklicht als bei Phenylderivaten [1], <5(C-4) ist gegenüber dem unsubstituierten Cyclohexan (26,6 ppm) kaum verändert, und es folgen (3(C-3,5) und <3(C-2,6) mit zunehmender Tieffeldverschiebung. <3(C-1) hängt deutlich von der weiteren Substitution des Metallatoms ab.…”