Biomedical subjects

Hanlin Nie

Publications and source records attributed to Hanlin Nie.

3 recordsLinked to original sources

PubMed1999

Porphyrazinehexamines and Dinitroporphyrazines: Synthesis, Characterization, and Complementary Electrochemistry.

Unsymmetrical porphyrazines, M[pz(H)(2)(R)(6)], with three substituted pyrroles (substituents, R = -NMe(2), propyl, or 4-tert-butylphenyl) at the periphery and one unsubstituted pyrrole have been synthesized from inexpensive and readily available materials. Linstead crossover macrocyclization of 8 with 9, 11, and 12 gave pigments 1, 3, and 5, respectively. Subsequent demetalation by treatment with TFA gave free-base porphyrazines 2, 4, and 6. Generally, pyrrolines 11 and 12 are better co-cyclization partners and give higher yields for the desired unsymmetrical porphyrazines compared to maleonitriles 9 and 10 when co-cyclized with 8. Nickel porphyrazine 7 was obtained by reaction of 6 with Ni(OAc)(2) in chlorobenzene and dimethylformamide. Both free-base and nickel porphyrazines (6 and 7) were readily nitrated by nitrogen dioxide in CH(2)Cl(2), yielding dinitroporphyrazines 18 and 19, respectively. Electrochemical studies have shown that porphyrazinehexamine 2 is easy to oxidize, having the first oxidation at E(1/2) = - 0.18 V, which is 0.91 and 1.04 V lower than that of 4 and 6, respectively. Dinitroporphyrazine 18, however, displays a 0.6 V of cathodic shift for the two reversible reduction waves compared to those observed for the parent porphyrazine 6.

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PubMed1998

Peripheral Palladium(II) and Platinum(II) Complexes of Bis(dimethylamino)porphyrazine.

The unsymmetrical porphyrazine (tetraazaporphyrin) bearing a single peripheral bis(dimethylamino) functionality, Mg[pz(NMe(2))(2)(Pr)(6)], was prepared by base-catalyzed cross condensation of dipropyl maleonitrile (in excess) with dimethylamino maleonitrile. The freebase (2H[pz(NMe(2))(2)(Pr)(6)]) and centrally metalated forms (M[pz(NMe(2))(2)(Pr)(6)]; M = Ni(II), Cu(II), Mn(III)) were prepared by treatment of Mg[pz(NMe(2))(2)(Pr)(6)] with trifluoroacetic acid and then the appropriate metal salt. PdCl(2) and PtCl(2) were coordinated to the peripheral bis(dimethylamino) chelates, yielding the bimetallic complexes, M[pz(NMe(2))(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(NMe(2))(2)(Pr)(6)]PdCl(2) 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(NMe(2))(2)(Pr)(6)]PtCl(2) 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(NMe(2))(2)(Pr)(6)]Pd(mnt) (13) was determined. Crystal data for C(85)H(109)Cl(3)N(24)Ni(2)Pd(2)S(4): space group P2(1)/n; a = 17.435(4) Å, b = 17.982(2) Å, c = 30.577(2) Å; beta = 104.27(2) degrees; Z = 4.

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PubMed1996

Dinuclear Copper(II) Complexes Incorporating a New Septadentate Polyimidazole Ligand.

The dinuclear copper(II) complexes [Cu(2)(tmihpn)(prz)](ClO(4))(2).2CH(3)CN (6) and [Cu(2)(tmihpn)(O(2)CCH(3))](ClO(4))(2).CH(3)CN (7) were prepared, where tmihpn is the deprotonated form of N,N,N',N'-tetrakis[(1-methylimidazol-2-yl)methyl]-1,3-diaminopropan-2-ol and prz is the pyrazolate anion. The crystal structures of 6 and 7 were determined and revealed that both complexes contain bridging alkoxide ligands as well as bridging pyrazolate and acetate ions, respectively. Crystal data: compound 6, triclinic, P&onemacr;, a = 18.089(2) Å, b = 22.948(3) Å, c = 9.597(2) Å, alpha = 93.37(2) degrees, beta = 94.49(2) degrees, gamma = 81.69(2) degrees, V = 3925.1 Å(3), Z = 4; compound 7, triclinic, P&onemacr;, a = 12.417(2) Å, b = 15.012(3) Å, c = 10.699(2) Å, alpha = 104.76(2) degrees, beta = 102.63(2) degrees, gamma = 99.44(2) degrees, V = 1830.1 Å(3), Z = 2. In compound 6, the coordination geometry around both copper centers resembles a distorted square pyramid, while the stereochemistry around the copper centers in 7 is best described as trigonal bipyramidal. Both complexes display well-resolved isotropically shifted (1)H NMR spectra. Selective substitution studies and integration data have been used to definitively assign several signals to specific ligand protons. Results from the solution (1)H NMR studies suggest that the basal and apical imidazole groups do not exchange rapidly on the NMR time scale and the solid state structures of the complexes are retained in solution. In addition, the magnetochemical characteristics of 6 and 7 were determined and provide evidence for "magnetic orbital switching". Antiferromagnetic coupling in 6 (J = -130 cm(-)(1)) is strong, while the copper centers in compound 7 are ferromagnetically coupled (J = +16.4 cm(-1)). Differences in the magnetic behavior of the two copper centers have been rationalized using the "ligand orbital complementary" concept. The ground state magnetic orbitals involved in spin coupling in 6 (d(x)()()2(-)(y)()()2) are different from those in 7 (d(z)()()2).

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