Functionalized Homoleptic cis- and trans-C,N-ortho-Chelated Aminoaryl Platinum(II) Complexes

Abstract

For the synthesis of corner building blocks with a 90°angle, to be used for the construction of larger structures, several homoleptic platinum(II) complexes [Pt(η 2 -C,N) 2 ] (10-14), as both cis-and trans-isomers, have been prepared starting from newly synthesized ortholithiated (dimethylamino)methyl arene ligands. The aryl groups of these arylplatinum(II) complexes contain additional substituents such as halides or methyl, naphthyl, or (dimethylamino)methyl groups. With these functionalities on the aryl rings the cis/trans ratio could be tuned. The presence of steric groups ortho to the metal center (methyl or naphthyl) favors the formation of planar-chiral cis-isomers. The trans-isomers isomerize irreversibly to the thermodynamically favored cis-isomers upon heating. The arylplatinum(II) complexes were used in various substitution reactions. Addition of a stronger coordinating ligand changes the denticity of the C,N-attached ligands. The halide functionalities were exploited for chemoselective lithiation and subsequent transmetalation reactions in order to synthesize the SnMe 3 -functionalized [Pt(C,N) 2 ] complexes. A Suzuki-Miyaura C-C coupling reaction on one of these complexes was also performed, resulting in the preparation of a mixed trinuclear palladium/platinum complex (25). The crystal structure determinations of four functionalized cis- [Pt(C,N) 2 ] complexes, cis-12‚Et 2 O, cis-14‚xC 6 H 6 , 19, and 25‚xCH 2 Cl 2 , are reported. With these structures it is shown that depending on the substituents, the degree of planarity around the platinum center can be tuned.

Exploring the Influence of the Aromaticity on the Anticancer and Antivascular Activities of Organoplatinum(II) Complexes

“…However,i nt he case of 2f,c omplete assignment of the structure required confirmation by X-ray diffraction (vide infra). The result is in agreement with the fact that in the absence of ad irecting group, such as bromide or iodide, [24] the metal induces ac ertain degree of regioselectivity so that cyclometalationo fl igand 1d-f occurs at the least sterically hindered position and yields exclusively the five-membered metallacycles 2d-f.…”

Palladium(II) Compounds with Fluorinated Pincer‐Type (SCS) Ligands: X‐ray Structures of C6H4‐1,3‐(CH2SC6H4F‐4)2 and [PdCl(SCS–Rf)] [Rf = C6H4F‐2, C6H4F‐3, C6H4F‐4, C6H4(CF3)‐2, and C6H4(CF3)‐4]

“…SCS pincer‐type palladium compounds have also been the focus of interesting structural and conformational studies such as isomeric exchange11 and dimer formation 12. Macromolecular and self‐assembled supramolecular chemistry have also profited from the useful properties of SCS pincer‐type compounds for the construction of polymetallic complexes,13 macrocycles,14 large metallodendrimers,15 functionalized polymers,16 mixed Pd–Au nanoparticles,17 polypincer‐porphyrin compounds,18 and supramolecular arrays of palladium 19…”

(Biphenyl-2,2′-diyl)[1,3-bis(diphenylphosphanyl)propane-κ2P,P′]platinum(II)

“…data reports bis(diphenylphosphanyl)propane-P:P]platinum(II), (Amijs et al, 2005). The average Pt-C bond lengths are similar for the series: 2.084 (3), 2.05 (1) and 2.065 (4) Å , respectively.…”