Peripheral palladium(II) and platinum(II) complexes of bis(dimethylamino)porphyrazine

The unsymmetrical porphyrazine (tetraazaporphyrin) bearing a single peripheral bis(dimethylamino) functionality, Mg[pz(NMe2)(2)CPr)(6)], was prepared by base-catalyzed cross condensation of dipropyl maleonitrile (in excess) with dimethylamino maleonitrile. The freebase (2H[pz(NMe2)(2)(Pr)(6)]) and centrally metalated forms (M[pz(NMe2)(2)-(Pr)(6)]; M = Ni(II), Cu(II), Mn(m)) were prepared by treatment of Mg[pz(NMe2)(2)(Pr)(6)] with trifluoroacetic acid and then the appropriate metal salt. PdCl2 and PtCl2 were coordinated to the peripheral bis(dimethylamino) chelates, yielding the bimetallic complexes, M[pz(NMe2)(2)(Pr)(6)]M'Cl-2 (M = Ni, Cu; M' = Pd, Pt). The heteroleptic [N-2-Pd-S-2]-capped porphyrazines were prepared readily by substituting the chloride ions of M[pz(NMe2)(2)(Pr)(6)]PdCl2 with the dithiolene chelates, maleonitriledithiolate (mnt(2-)), benzenedithiolate (bdt(2-)), and 1,3-dithiole-2-one-4,5-dithiolate (dmid(2-)). The [N-2-Pt-S-2] complexes were prepared by reaction of M[pz(NMe2)(2)(Pr)(6)]PtCl2 with the dialkyltin-protected dithiolates dibutyltin(toluene-3,4-dithiolate) and dibutyltin(dmit). The peripheral heteroleptic [N-2-M'-S-2] core was found to be electroactive for electron-rich dithiolene ligands (bdt(2-), E-1/2(Pd-III/Pd-II) = 0.22 V; tdt(2-) E-1/2(Pt-III/Pt-II) = 0.20 V; dmid(2-), E-1/2(Pd-III/Pd-II) = 0.19 V; dmit(2-), E-1/2(Pt-III/Pt-II) = 0.19 V) but not for the relatively electron-poor dithiolene, maleonitriledithiolate (mnt(2-)). The X-ray structure of Ni[pz(NMe2)(2)(Pr)(6)]-Pd(mnt) (13) was determined. Crystal data for C85H109Cl3N24Ni2Pd2S4: space group P2(1)/n;,a 17.435(4) Angstrom, b = 17.982(2) Angstrom, c = 30.577(2) Angstrom; beta = 104.27(2)degrees; Z = 4.