Cyclometallated platinum complexes with thienyl imines. X-ray crystal structure of [PtMe{3-(PhCH2NCH)C4H2S}PPh3]

Cyclometallated platinum complexes with heterocyclic ligands

“…The proposed structure consisting of a three-fused ring system containing a five-membered metallacycle is shown in Chart 2. All spectral parameters for compound 4a are in good agreement with the results obtained for analogous aryl cyclometallated compounds [2,3]. As shown in Table 1, the value obtained for d( 195 Pt) moves to higher fields for cyclometallated complexes when compared to the value for the corresponding non-cyclometallated precursor, an effect which is larger for the furane derivative (Dd ¼ 212 PPM) than for benzene or thiophene analogues.…”

“…As previously reported for thienyl systems [3], the site of metallation was the C(2) position of the furane ring. This is consistent with the J (H-H) value of 6 Hz obtained for the two aromatic protons (H 4 and H 5 ).…”

“…The coordination of the ligand through the nitrogen atoms is confirmed by the coupling of both amine and imine protons to platinum. The chemical shifts observed for 195 Pt are in the expected range [8] [3] which, under these conditions, have been reported to yield the corresponding cyclometallated compounds with elimination of methane. The lower tendency of the furane derivative towards cyclometallation is attributed to the lower degree of aromaticity of furane (16 kcal/mol) versus benzene (36 kcal/mol) or thiophene (29 kcal/mol) [9].…”

“…The latter are attractive for regioselectivity studies due to the presence of non-equivalent positions available for metallation. Following our studies on intramolecular C-H bond activation of benzene [2] and thiophene rings [3] at platinum, we decided to study the activation of such bonds in furanes and pyridines using a similar strategy. The reactions of [Pt 2 Me 4 (l-SMe 2 ) 2 ] (1) with imine ligands derived from 3-furaldehyde, 3-or 4-pyridinealdehyde and N ; N -dimethylethylenediamine or 2-chlorobenzylamine are reported.…”

Higher fluorescence in platinum(iv) orthometallated complexes of perylene imine compared with their platinum(ii) or palladium(ii) analogues

“…In adition, the 31 P NMR spectrum of 7 is also a diagnostic of the Pt center oxidation state as the observed chemical shift at δ --4.6 ppm, is 35 ppm upfield the corresponding Pt II precursor 2; the reduced 1 J Pt--P coupling constant (1015 Hz) is also consistent with formation of Pt IV . 14,19,20,21 The 195 Pt NMR resonances were located indirectly by 195 Pt/ 1 H 2D HMBC experiments (see Fig. 1), which shows the expected coupling constants as assigned in the experimental part.…”