Intramolecularly stabilized 1,4-phenylene-bridged homo- and heterodinuclear palladium and platinum organometallic complexes containing N,C,N-coordination motifs; eta 1-SO2 coordination and formation of an organometallic arenium ion complex with two Pt-C sigma-bonds

The new ligand precursors [1-(Me3Si)-4-(R){C-6(CH2NMe2)(4)-2,3,5,6}] (2, R = Me3Si; 3, R = H) have been used for the preparation of ionic 1,4-phenylen e-bridged bispalladium(II) and palladium(II)-platinum(II) complexes [1-{M(M eCN)}-4-{M'(MeCN)}{C-6(CH2NMe2)(4)-2 ,3,5,6}]-(BPh4)(2) (5b, M = M' = Pd; 1 0, M Pd, M' = Pt). Lithium-halogen exchange of the new ligand precursor C6B r2(CH2NMe2)(4)-2,3,5,6, 11, generates a presumably polymeric organodilithiu m reagent, 12, which in a transmetalation reaction with [PtCl2Et2S)(2)] aff ords the 1,4-phenylene-bridged bisplatinum complex [1,4-(PtCl)(2){C-6(CH2NM e2)(4)-2,3,5,6}], 13. Reaction of colorless 13 with SO2 affords the unique orange bis-SO2 adduct [1,4-{PtCl(eta(1)- SO2)}(2){C-6(CH2NMe2)(4)-2,3,5,6}] , 16, of which an X-ray crystal structure has been determined. The ionic de rivative [1,4-{Pt(MeCN)}(2){(C-6(CH2NMe2)(4)-2,3,5,6}](BPh4)(2), 14b, obtai ned by reaction of 13 with AgOTf in MeCN followed by addition of NaBPh4, ha s been the subject of an X-ray crystal structure determination, The X-ray m olecular structures of 5b, 10, and 14b have been determined and show intram olecular M ... M distances of ca. 6.5 Angstrom. The bistriflate complex [1, 4-{Pt(MeCN)}(2){C-6(CH2NMe2)(4)-2,3,5,6}](OTf)(2), 14a, has also been used for the synthesis of the organometallic polymer {[1,4-{PtI(mu-I)}(2){C-6(CH 2N(H)Me-2)(4)-2,3,5,6}](n)}- (OTf)(2n), 24. Triflate complex 14a slowly rea cts with iodomethane to afford the dark red air-stable crystalline complex [1,4-{PtI}(2){C6Me-1-(CH2NMe2)(4)-2,3,5,6}](OTf), 23. The X-ray molecular s tructure of 23 shows it to be a unique arenium ion species with two para-or iented sigma-bonded iodoplatinum substituents.