Insertion of tin(II) bromide into Pt–X (X=Cl, Br) bond of dimethylplatinum(IV) complexes: A novel polymorphic form of [PtBr2(bpy)]

Synthesis, Luminescence, and Structure of a Polymorphic Polyfluorinated Diiodoplatinum(II) Diimine Complex

PtI₂(5,5'-bis(HCF₂CH₂OCH₂)-2,2'-bpy)], 55-2FH-PtI₂, is the first example of a substituted fluorinated diiodoplatinum diimine complex that exhibits polymorphism. The complex, upon recrystallization, forms two different polymorphs, denoted as α and β forms. The luminescence of the α and β forms are the same in glassy solution at 77 K; however, in the solid state, they differ significantly. The major difference between them lies in the solid-state packing of the crystalline structure. The α form is a square planar polyfluorinated PtI₂-containing complex. Its extended herringbone structure consists of two neighboring stacked bipyridyl planes that do not overlap. The α form emits stronger than its parent molecule, [PtI₂bpy], and much stronger than the β polymorph. The β form has a slight tetrahedral distortion about the metal center that ultimately changes the geometry of the complex and decreases the d-orbital splitting from square planar. Furthermore, overlapping bipyridine rings in the extended structure of the β form quench the emission thus resulting in a lower energy emission. Additionally, the β form shows only one type of C-H···O intermolecular stacking interaction that can cause the moderate distortion of the metal core.

A Bridging Peroxide Complex of Platinum(IV)

The photolysis of the allylplatinum(IV) complex [PtBr(C₃H₅)(4-MeC₆H₄)₂(bipy)], 1, bipy = 2,2'-bipyridine, in air yielded [{PtBr(4-MeC₆H₄)₂(bipy)}₂(μ-O₂)], 2, the first diplatinum(IV) complex containing a single bridging peroxide ligand. The PtO-OPt bond distance in 2 is 1.481(3) Å. Complex 2 is thought to be formed by homolysis of the allyl-platinum bond of 1, followed by reaction of the platinum(III) intermediate [PtBr(4-MeC₆H₄)₂(bipy)] with oxygen.

The role of solvent in organometallic chemistry — Oxidative addition with dichloromethane or chloroform

Dimethylplatinum(II) complexes [PtMe2(NN)], with NN = diimine ligand, can react with dichloromethane or chloroform solvent to give the corresponding organoplatinum(IV) complexes [PtClMe2(CH2Cl)(NN)] or [PtClMe2(CHCl2)(NN)], respectively. The products can exist in isomeric forms, corresponding to products of cis or trans oxidative addition. The structures of three dichloromethane adducts and one chloroform adduct are reported.

Structural Chemistry of [MX2(bipy)] (M=Pd, Pt; X=Cl, Br, I): the Yellow Polymorph of Dichlorido(2,2'-bipyridine)platinum(II) and Diiodido(2,2'-bipyridine)palladium(II), and Overview of this System

Synchrotron data have been used to determine the structures of the yellow polymorph of dichlorido(2,2′-bipyridine)platinum(ii) (1), and diiodido(2,2′-bipyridine)palladium(ii) (2), allowing a detailed comparison of the crystal chemistry of [MX2(bipy)] (M = Pd, Pt; X = Cl, Br, I), which exhibit polymorphism involving nine structures distributed over five space groups. Complex 1 crystallizes in space group Pbca (a = 18.2540(7), b = 15.6970(7), c = 7.3560(6) Å), and 2 in space group C2/c (a = 17.149(1), b = 9.8050(8), c = 7.548(1) Å, β = 110.72(1) °).