A hydrogen atom in an organoplatinum-amine system. 1. Synthesis and spectroscopic and crystallographic characterization of novel zwitterionic complexes with a Pt(II)-.cntdot..cntdot..cntdot.H-N+ unit
Year: 1992
Type: article
Abstract: The unusual bridging-hydrogen complexes PtX(L-C,N)(LH-C,H) containing a zwitterionic Pt(II)--.H-N+ moiety have been obtained in a reaction of cis-Pt(L-C,N), with R2SnX, (R = Me, Ph; X = C1, Br) in a mixture of CH2C12 and MeOH.The chelating amine ligand systems L used in this reaction are [ 1-Cl&6NMe2-8]-, [C6H4CH2NMq-2]-, and [C6H4CH2NEt2-2]-.The complex PtC1( l-CloH6NMe2-8-C,N)( l-CloH6NHMe2-8-C,H) can also be obtained by reaction of cis-Pt( 1- CloH6NMe,-8-C,N), with dry HC1.The bridging proton of the zwitterionic Pt(II)--.H-N+ moiety shows a characteristic 'H NMR resonance at ca. 11-16 ppm with a 1J('95Pt,'H) of ca.65-180 Hz; the latter decreases with increasing ligand flexibility.In the Pts-H-N moiety of the PtX(L-C,N)(LH-C,H) complexes, an increase of the Pt-H interaction is associated with a simultaneous decrease of the H-N interaction.When L is chiral [C6H4CH(Me)NMe2-(R)-2]-, cis-Pt(L-C,N), affords in a reaction with Me2SnBr2 the nonbridging complex PtBr(C6H4CH(Me)NMe2-(R)-2-C,N)(C6H4CH(Me)NHMe2-(R)-2-C) as the major product.The X-ray crystal structures of both a bridging complex, i.e.PtBr(l-CloH6NMe2-8-C,N)(l-ClOH6NHMe2-8-C,H), and a nonbridging complex, i.e.PtBr(C6H4CH(Me)NMe2-(R)-2-C,N)(C6H4CH(Me)NHMe2-(R)-2-C), are described.Especially the latter shows good evidence that the bridging interaction is largely electrostatic.Internal steric influences only affect the stability of the bridging moiety when they arise from groups on the benzylic carbon atom.Crystal data for PtBr(l-C,oH6NMe2-8-C,N)(l-C,oH6NHMe2-8-C,H) at 100 K: a = 9.469 ( 1) A, b = 30.481(1) A, c = 7.298 (1) A, / 3 = 91.81(1)O, Z = 4, Dcalcd = 1.945 g ~m -~, and space group Cc.Crystal data for PtBr(C6H4CH(Me)NMe2-(R)-2-C,N)(C6H4CH(Me)NHMe2-(R)-2-C) at 298 K: a = 11.136(1) A, b = 12.0577 (8) A, c = 15.378(1) A, Z = 4, Dmld =1.841 g cm-j, and space group P2,2,2,.
DOI: 10.1021/ja00051a025
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W243569686