Synthesis and Characterization of Group 14−Platinum(IV) Complexes

Abstract

The reactions of group 14 compounds Me n EX4-n (E = Si, Ge, Sn; X = Cl, Br, I) with electron-rich [PtMe2(diimine)] complexes give facile trans oxidative addition of the E−X bond (E = Si, X = Br, I; E = Ge, Sn, X = Cl, Br, I). The oxidative additions occur more readily for Me n EX4-n in the sequences X = I > Br > Cl and E = Sn > Ge > Si. The first stable silylplatinum(IV) complexes have been prepared in this way, and the X-ray crystal structure of [PtIMe2(Me3Si)(bpy)] shows an exceptionally long Pt−I bond length (2.963(1) Å) consistent with the high trans influence of the trimethylsilyl group. 1H NMR studies show that the oxidative addition involving germanium and tin reagents is easily reversible. Several of the platinum(IV)−tin complexes have a second molecule of tin reagent incorporated into the crystal lattice. The X-ray crystal structure of [PtIMe2(Me3Sn)(bpy- t bu2)]2·Me3SnI· CH2Cl2 shows two distinct complexes (1:1 ratio) to be present in the unit cell. The first is the product of trans oxidative addition, [PtIMe2(Me3Sn)(bpy- t bu2)], and the second is [PtIMe2(Me3Sn)(bpy− t bu2)]·Me3SnI. In this second complex the platinum-bound iodo ligand coordinates to the tin center of the Me3SnI molecule to give a trigonal-bipyramidal tin center.

1H, 13C, 195Pt and 15N NMR structural correlations in Pd(II) and Pt(II) chloride complexes with various alkyl and aryl derivatives of 2,2′‐bipyridine and 1,10‐phenanthroline

“…Pawlak et al (Tables S2 and S3, Supporting Information) exhibits the enhancement of the 1 H deshielding effect for these protons in the F < CN < Cl < Br < I order: [20,21,35] 0.69 ppm → 1.24 ppm for [M(4,4 -dbbpy)(CH 3 )I]. [21,34] Such 1 H deshielding phenomena and their structural dependencies can be probably explained by the combination of inductive effects (caused by the presence of electronegative halogen atoms) and heavy metal influence (leading to the increase of 1H coord parameters with the atomic mass of the halide or the platinide).…”

Synthesis, characterization, DNA binding studies and in vitro cytotoxicity of platinum(II)-dihalogenido complexes containing bidentate chelating N-donor ligands

“…Infrared spectra of the complexes were recorded on a ThermoNicolet NEXUS 670 FT-IR spectrometer using the ATR diamond-plate technique from 200-4000 cm -1 . 1 H-, 13 C-and 195 Pt-NMR spectra were recorded on a 600 MHz JEOL JNM-ECA600II spectrometer at 298 K in DMF-d 7 . The reference standard used for 1 H-and 13 C-NMR measurements was tetramethylsilane (TMS).…”

“…Other platinum(II) complexes with similar composition, involving the 4-methyl-and 5-methyl-2,2'-bipyridine ligands, and 5-amino-1,10-phenanthroline ligands, were studied for interactions with DNA either as cross-linking or intercalation agents [9][10][11]. Despite a number of dichlorido-platinum(II) complexes with diimine N,N´-bidentate ligands, there are only a few reports regarding the preparation and characterization of dibromido and diiodido complexes involving the same type of N-donor ligands, such as [Pt(bpy)X 2 ], [Pt(phen)X 2 ], [Pt(4-tButbpy)X 2 ] and [Pt(4-Butbpy)X 2 ], where X = Br or I, 4-tButbpy = 4,4´-ditert-butyl-2,2´-bipyridine and 4-Butbpy = 4,4´-di-tert-butyl-2,2´-bipyridine [12][13][14][15][16], and only one report indicating their biological activities (i.e. ability to react with singlet oxygen) [17].…”

Structural characterisation of heterometallic platinum complexes with non-transition metals. Part I: heterodimeric complexes

“…There are eight Pt(IV)Sn(II) dimers (R ü egger et al, 1988;Smeets et al, 1992;Levy et al, 1996a,b;Canty et al, 1999;Janzen et al, 2001) in which two non-equivalent units: Pt( η 2 -4,4 ′ -Bu t 2 bpy) (Me) 2 Cl with SnCl 3 or SnCl 2 (Ph) (Janzen et al, 2001); Pt[ η 3 -CH 2 C(Me)CH 2 ]( η 2 -styrene) with SnCl 3 (R ü egger et al, 1988); Pt( η 2 -4,4 ′ -Bu t 2 bpy)(Me) 2 with Sn(Me) 2 Cl (Levy et al, 1996a); Pt( η 2 -4,4 ′ -Bu t 2 bpy(Me) 2 I with Sn(Me) 3 (Levy et al, 1996b); Pt( η 2 -Me 2 ann) 2 Cl with SnCl 3 (Smeets et al, 1992); Pt( η 2 -4,4 ′ -Bu t 2 bpy)(Ph)(CNBu t )(Bz) with Sn( η 5 -B 11 H 11 ) and Pt( η 3 -pz 3 BH)(Me) 2 with Sn(Me) 3 (Canty et al, 1999) are connected only via a direct Pt(IV)-Sn(II) bond, which elongated in the order: 2.4932 (7) (Canty et al, 1999). In Levy et al (1996a), the Pt(IV) atom is five-(PtN 2 C 2 Sn) coordinated and in remainders six-PtN 2 C 2 XSn [X = Cl (Smeets et al, 1992;Janzen et al, 2001) or I (Levy et al, 1996b)], PtC 5 Sn (R ü egger et al, 1988), PtC 3 N 2 Sn and PtN 3 C 2 Sn (Canty et al, 1999) coordinated.…”

“…In Levy et al (1996a), the Pt(IV) atom is five-(PtN 2 C 2 Sn) coordinated and in remainders six-PtN 2 C 2 XSn [X = Cl (Smeets et al, 1992;Janzen et al, 2001) or I (Levy et al, 1996b)], PtC 5 Sn (R ü egger et al, 1988), PtC 3 N 2 Sn and PtN 3 C 2 Sn (Canty et al, 1999) coordinated. The Sn(II) atom is found with the chromophores: SnCl 3 Pt (R ü egger et al, 1988;Smeets et al, 1992;Janzen et al, 2001), SnC 2 ClPt (Levy et al, 1996a;Janzen et al, 2001), SnC 3 Pt (Levy et al, 1996b;Canty et al, 1999) and SnB 5 Pt . In yellow Pt(IV)Sn(II) dimer (Janzen et al, 1999, (7) Å ] and heterobidentate non-chelating μ -η 2 -SeC(CO 2 Me) = C(CO 2 Me) ligand via Se to Pt(IV) and via C to Sn(II).…”