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(Pr)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(III)) 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‘Cl2 (M = Ni, Cu; M‘ = Pd, Pt). The heteroleptic [N2−Pd−S2]-capped porphyrazines were prepared readily by substituting the chloride ions of M[pz(NMe2)2(Pr)6]PdCl2 with the dithiolene chelates, maleonitriledithiolate (mnt2-), benzenedithiolate (bdt2-), and 1,3-dithiole-2-one-4,5-dithiolate (dmid2-). The [N2−Pt−S2] 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 [N2−M‘−S2] core was found to be electroactive for electron-rich dithiolene ligands (bdt2-, E 1/2(PdIII/PdII) = 0.22 V; tdt2-, E1/2(PtIII/PtII) = 0.20 V; dmid2-, E 1/2(PdIII/PdII) = 0.19 V; dmit2-, E1/2(PtIII/PtII) = 0.19 V) but not for the relatively electron-poor dithiolene, maleonitriledithiolate (mnt2-). The X-ray structure of Ni[pz(NMe2)2(Pr)6]Pd(mnt) (13) was determined. Crystal data for C85H109Cl3N24Ni2Pd2S4: space group P21/n; a = 17.435(4) Å, b = 17.982(2) Å, c = 30.577(2) Å; β = 104.27(2)°; Z = 4.