The reactions of cis -[Pt(OAc) 2 (DMSO) 2 ] with 2 equiv of sym N , N ′, N ″-triarylguanidines, [ArN=C(NHAr) 2 ], in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(OAc){κ 1 N (ArN=C(NHAr) 2 )}] [ sym = symmetrical; Ar = 2-MeC 6 H 4 ( 1 ) and 2,4-Me 2 C 6 H 3 ( 2 )], in 82 and 84% yields, respectively. The salt metathesis reaction of 1 with 1 equiv of AgTFA in CH 2 Cl 2 at room temperature (RT) afforded [Pt{κ 2 ( C , N )}(TFA){κ 1 N (ArN=C(NHAr) 2 )}] ( 3 ) in 94% yield. The reaction of cis -[Pt(TFA) 2 (DMSO) 2 ] with 1 equiv of [ArN=C(NHAr) 2 ] in toluene under reflux condition for 8 h afforded six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(TFA)(DMSO)] [Ar = 2-MeC 6 H 4 ( 4 ), 4-MeC 6 H 4 ( 5 ), 2,4-Me 2 C 6 H 3 ( 6 ), and 2-(MeO)C 6 H 4 ( 7 )], in ≥73% yields. The reaction of trans -[PtCl 2 (PhCN) 2 ] with 2 equiv of [ArN=C(NHAr) 2 ] in toluene under reflux condition for 48 h afforded trans -[PtCl 2 {ArN=C(NHAr) 2 } 2 ] [Ar = 2-MeC 6 H 4 ( 8 ) and 2,4-Me 2 C 6 H 3 ( 9 )] in 90 and 45% yields, respectively. Complexes 8 and 9 were separately refluxed in MeOH for 8 h to afford six-membered cycloplatinated guanidines, [Pt{κ 2 ( C , N )}(μ-Cl)] 2 ( 10 and 11 ), in 93 and 96% yields, respectively, with concomitant formation of the respective guanidinium salts, [(ArNH) 3 ...
Dawn of nanocatalysis has begun a new era for chemistry by promoting the design of new catalytic production processes in organic synthesis with utmost level of waste minimization by addressing...
Separate reactions of cycloplatinated 2-tolyl-and 2-anisylguanidine complexes, [Pt{κ 2 (C,N)}(OC(O)CF 3 )(S(O)Me 2 )] (1 and 2), with Hg(OC(O)CF 3 ) 2 in 1:0.5 and 1:1 molar ratios afforded the one-dimensionalas bright red crystals and the discrete tetrametallic complex [Pt II {κ 2 (C,N)}(μ 2 -OC(O)CF 3 ) 2 Hg I −] 2 (4) as yellow crystals in good yields. The two different products obtained in the aforementioned reactions are ascribed to the subtle differences in the N substituent of the guanidinate(1−) ligands in 1 and 2. The plausible mechanisms of formation of 3 and 4 are outlined. Complexes 3 and 4 were characterized by elemental analyses and IR and multinuclear NMR ( 1 H, 13 C{ 1 H}, 19 F, and 195 Pt) spectroscopy. Complex 4 was also characterized by 199 Hg NMR spectroscopy. The molecular structures of 3•C 7 H 8 and 4 were determined by single-crystal X-ray diffraction studies. 1D CP 3•C 7 H 8 contains a Pt(III)−Hg(0)−Pt(III)(μ 2 -S(O)Me 2 -S,O) repeating unit with a pair of unsupported Pt−Hg covalent bonds, while 4 contains a Pt(II)−Hg(I)−Hg(I)−Pt(II) chain with a pair of trifluoroacetate ligand supported Pt→Hg coordinate bonds. 1D CP 3•C 7 H 8 falls apart into a mixture of three species, namely 6−8 and 9−11 in C 6 D 6 and CDCl 3 , respectively, as revealed by multinuclear NMR spectroscopy. In CDCl 3 , 4 partially isomerizes to [Pt II (OC(O)CF 3 )(μ 2 -OC(O)CF 3 ){κ 3 μ 2 (C,N,O)}Hg I −] 2 ( 12), wherein each Pt→Hg coordinate bond is supported by one μ 2bridging trifluoroacetate ligand and one chelating bridging guanidinate(1−) ligand, as inferred from variable-temperature 1 H and 19 F NMR spectroscopy. Complex 12 is the major species and 4 is the minor species in CDCl 3 , while opposite situation prevails in C 6 D 6 . The observance of a mixture of two solution species for 4 is ascribed to a rapid "carboxylate shift" process induced by the oxygen atom of the N(C 6 H 4 (OMe)-2) unit of the guanidinate(1−) ligand through neighboring-group participation. UV−visible absorption and emission spectra of 4 were measured in CHCl 3 , and from the outcome of the investigation, the possible existence of [Cl 2 (H)C−Cl•••Pt II (OC(O)CF 3 )(μ 2 -OC(O)CF 3 ){κ 3 μ 2 (C,N,O)}Hg I −] 2 (12″) was suggested, which is likely to have a pair of Pt− Hg covalent bonds made possible by CHCl 3 coordination on the sixth site of the Pt(II) atom.
Ethylene Propylene Diene Monomer (EPDM) rubber is for major used in engineering and many technical works and its application like automobile, constructions, electronic industries, and electric and many more. Industries commonly EPDM use for making the rubber inlet/outlet hoses for car and other vehicle. EPDM rubber properties are like good weather resistance ability as well as heat ozone. The resistance of steam is outstanding. EPDM rubber commonly is used for seals in automobile area. In the present review paper, different hardness of EPDM has been discussed on the basis of mixing or adding different proportion of graphene and carbon black (CB) and other additives. Also discussed how improve the performance of EPDM using silica and graphene and titanium dioxide and other additives and synergistic effect of graphite nanotubes on EPDM nanotubes. Effect of graphene on non-polar and polar rubber matrix also discussed with mechanical behaviour of EPDM.
The reactions of cycloplatinated guanidinate(1−) complexes 1−6 with AgTFA (TFA = OC(O)CF 3 ) in 1:1 and 1:2 Pt II /Ag I molar ratios afforded complexes containing three types of Pt 2 Ag 2 skeletons (7−10, 11, and 13), one 1D CP containing Pt 2 Ag 3 skeleton ( 16), and a Pt 2 Ag 4 complex (17) in 91−95% (method 1), 73−82% (method 2) (7−10), and 54−79% (11, 13, 16, and 17) yields. The reactions of 11 with 2,6-XylNC (2,6-Xyl = 2,6-Me 2 C 6 H 3 ) and 4-DMAP (4-dimethylaminopyridine) gave a neutral complex 18 and an ionic complex 19, respectively. Molecular structures of 12 complexes were unambiguously determined by single-crystal X-ray diffraction. Ten complexes contain unprecedented PtAg skeletons and are shown to contain multiple number of dative Pt → Ag bonds supported by the TFA ligand, platinated carbon of the TAG ligand, or both these ligands in conjunction with the Ag−Ag contacts stabilized by argentophilic interaction. Further, the new complexes were characterized by analytical, IR, and multinuclear NMR ( 19 F, 1 H, 13 C{ 1 H}, and 195 Pt) spectroscopies, powder X-ray diffraction, and TGA/DTA. In solution, 9 and 19 exist in more than one form as identified by multinuclear NMR, and this behavior is ascribed to the restricted (N 2 )C−N(H)Ar single-bond rotation of the TAG ligand. The photophysical properties of 9 and 11 are reported.
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