Takeshi Ken Miyamoto

Steric influence on platinum(II) ascorbate complexes

From the reaction between dihydroxoplatinum(II) and l-ascorbic acid, two types of platinum(II) ascorbate complexes were obtained and structurally characterized with ethylenediamine (en), N,N-dimethylethylenediamine (dmen) and N,N,N′-trimethylethylenediamine (trimen) as stabilizing ligands. In [Pt(en)(asc-C,O)] (1), [Pt(dmen)(asc-C,O)] (2) and [Pt(trimen)(asc-C,O)] (4), the ascorbate dianion forms a five-membered chelate ring, coordinating to the Pt(II) ion at the 2-carbon and the 5-oxygen atoms (C,O-chelate). From the same mother solution, crystals of [Pt(trimen)(asc-O,O′)] (3) were obtained during the precipitation of 4; in 3 the ascorbate is bound to the Pt at the 2- and 3-oxygen atoms (O,O′-chelate). Compounds 3 and 4 are the first well-characterized linkage isomers among the transition-metal ascorbate complexes. The O,O′-chelated 3 slowly changes to the C,O-chelated 4 in an aqueous solution. Bulkiness of the stabilizing ligand, i.e. en, dmen and trimen has an influence on the formation of the C,O-chelated species, 1, 2 and 4.

A phosphane analog of nedaplatin: preparation and structural characterization of cis-bis(trimethylphosphane)-(glycolato-O,O′)platinum(II)

Abstract A water-soluble cis -bis(phosphane)platinum(II) complex, cis -[bis(trimethylphosphane) (glycolato- O , O ′)platinum(II)] ( 1 ), was crystallized from an organic solvent as a hemihydrate, [Pt(PMe 3 ) 2 (OCH 2 COO)]·0.5H 2 O ( 1 ·0.5H 2 O), which is an analog of the anticancer drug nedaplatin, [Pt(NH 3 )) 2 (OCH 2 COO)] ( 1′ ). Crystal data at 160(5) K are: C 8 H 21 O 3.5 P 2 Pt, monoclinic, P 2 t (No. 4), a = 9.012(3), b = 9.824(7), c = 15.417(3) A, β = 97.92(2)°, U = 1351.8(11) A 3 , Z = 4; those measured at 293(2) K are: a = 9.066(2), b = 9.948(2), c = 15.525(1) A , β = 97.40(1)°, U = 1388.5(4) A 3 . The glycolate dianion forms a five-membered chelate ring, coordinating to the Pt(II) ion not only at an O atom of the carboxyl group but also at the hydroxy. The NMR spectra show that the hydroxy group ligates to the Pt(II) in the solution of organic solvents as well as in the crystalline state, but that it exchanges with a water molecule in aqueous solution.

The trans influence of the pyridine ligand on ruthenium(II)-porphyrin-carbene complexes.

In the two ruthenium(II)-porphyrin-carbene complexes (dibenzoylcarbenyl-kappaC)(pyridine-kappaN)(5,10,15,20-tetra-p-tolylporphyrinato-kappa(4)N)ruthenium(II), [Ru(C(15)H(10)O(2))(C(5)H(5)N)(C(48)H(36)N(4))], (I), and (pyridine-kappaN)(5,10,15,20-tetra-p-tolylporphyrinato-kappa(4)N)[bis(3-trifluoromethylphenyl)carbenyl-kappaC]ruthenium(II), [Ru(C(15)H(8)F(6))(C(5)H(5)N)(C(48)H(36)N(4))], (II), the pyridine ligand coordinates to the octahedral Ru atom trans with respect to the carbene ligand. The C(carbene)-Ru-N(pyridine) bonds in (I) coincide with a crystallographic twofold axis. The Ru-C bond lengths of 1.877 (8) and 1.868 (3) A in (I) and (II), respectively, are slightly longer than those of other ruthenium(II)-porphyrin-carbene complexes, owing to the trans influence of the pyridine ligands.

First Isolations and Structures of cis -Bis(phosphoranido) Complexes

The first cis -bis(phosphoranido) palladium(II) and platinum(II) complexes were prepared by the reaction of a lithium phosphoranide, bearing two 8-oxy-1-naphthyl groups with (dmpe)MCl 2 (M; Pd, Pt). The crystal structures of the racemic isomers of the complexes are determined by the X-ray structural analyses.

A ruthenium(II)-porphyrin-carbene complex with a weakly bonded methanol ligand.

The title diphenylcarbene porphyrin complex (diphenylcarbenyl-kappaC)(methanol-kappaO)(5,10,15,20-tetra-p-tolylporphyrinato-kappa(4)N)ruthenium(II) methanol solvate, [Ru(C(13)H(10))(C(48)H(36)N(4))(CH(4)O)].CH(4)O, has a six-coordinate Ru atom with a methanol molecule as the second axial ligand. The carbene fragment is slightly distorted from an ideal sp(2) configuration, with a C(phenyl)-C(carbene)-C(phenyl) angle of 112.2 (3) degrees. The Ru-C bond length of 1.845 (3) A is comparable with other carbene complexes. The two phenyl rings of the carbene ligand are perpendicular to the carbene plane. Methanol solvate molecules link the methanol ligands of adjacent porphyrin complexes via hydrogen bonds.

Enantiomorphs of a carbene-ruthenium(II)-porphyrin complex with four 'chiral pillars'.

The chiral metalloporphyrin (dibenzoylmethylene-kappaC)(ethanol-kappaO){5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl]porphyrinato-kappa(4)N}ruthenium(II)-ethanol-dichloromethane (1/2/2), [Ru(C(84)H(76)N(4))(C(15)H(10)O(2))(C(2)H(6)O)].2C(2)H(6)O.2CH(2)Cl(2), and its enantiomorph were prepared from enantiomerically pure porphyrins. The enantiomers are potential versatile catalysts for asymmetric cyclopropanation, aziridination or epoxidation. In each compound, the rather large dibenzoylcarbene group is squeezed between four columnar 1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl groups at the meso positions resulting in a doming deformation of the porphyrin core. The dibenzoylcarbene group has an anti conformation. The benzoyl O atoms make short van der Waals contacts (< 2.6 A) with the methine groups of the chiral columnar substituents at the 10 and 20 positions of the porphyrin rings. A hydrogen-bonded supramolecular chain is formed parallel to the b axis by interactions between the benzoyl O atom and the hydroxy groups of the coordinated and uncoordinated ethanol molecules.

A five-coordinate ruthenium(II)–porphyrin–carbene complex: [bis(3-trifluoromethylphenyl)methylene-κC](5,10,15,20-tetra-p-tolylporphyrinato-κ4N)ruthenium(II)

The stable title trifluoromethyl-substituted carbenyl metalloporphyrin, [Ru(C(15)H(8)F(6))(C(48)H(36)N(4))], has a five-coordinate Ru atom which is displaced from the porphyrin N(4) plane towards the axial carbene ligand by 0.230 (3) A. The Ru--C(carbene) bond coincides with a crystallographic twofold axis and its length of 1.841 (6) A is notably shorter than the value of 1.868 (3) A in the pyridine adduct.

NEW LIPOPHILIC BISPOCKET-PORPHYRINS FOR CHEMOTHERAPY OF CANCER (PART I); PREPARATION AND PROPERTIES OF 5,10,15,20-TETRAKIS(3′,5′-DI-t-BUTYLPHENYL) PORPHYRIN METAL COMPLEXES1

Abstract A series of highly lipophilic bis-pocket porphyrins, 5,10,15,20-tetrakis(3′, 5′-di-t-butylphenyl)porphyrin with five metals (copper(II), nickel(II), zinc(II), cobalt(II), and iron(III)), have been prepared and characterized on the basis of electronic, infrared and 1H NMR spectra. Although electronic spectra of these porphyrins are substantially the same as their prototype tetraphenylporphyrin complexes of the respective metals, their solubility in common organic solvents such as chloroform, benzene, and hexane is dramatically enhanced.

(5,10,15,20-Tetra­phenyl­porphyrinato-κ4N)(2,2,2-trifluoro-1-phenyl­ethyl­idene-κC1)ruthenium(II): a stable fluorinated alkyl­idene complex of a ruthenium(II) porphyrin

In the title compound, [Ru(C44H28N4)(C8H5F3)], the fluorinated alkylidene group is bound to a five-coordinate Ru atom, which is located toward the carbene C atom, 0.3301 (5)Å from the least-squares plane of the C20N4 porphyrin core. The Ru=C bond is tilted slightly from the normal to the C20N4 least-squares plane due to steric repulsion between the porphyrinate ligand and the bulky trifluoromethyl group. The Ru=C bond length of 1.838 (2) Å is comparable with those in bis(subsituted phenyl)carbene analogs.

The first metalloporphyrin dimer linked by a bridging phenylenedicarbene ligand

In the first bis[ruthenium(II)-porphyrin]-dicarbene complex, mu-[1,4-phenylenebis(phenylmethylidene-kappaC)]bis[(ethanol-kappaO)(5,10,15,20-tetra-p-tolylporphyrinato-kappa4N)ruthenium(II)] 1,2-dichloroethane trisolvate, [Ru2(C20H14)(C48H36N4)2(C2H6O)2].3C2H4Cl2, an inversion center is located at the center of the mu-phenylene group, leading to a parallel arrangement for the pair of porphyrin ring systems. The bond lengths and angles compare favourably with literature values for ruthenium-porphyrin-monocarbene complexes; the Ru=C(carbene) bond length and the C(phenyl)-C(carbene)-C(phenylene) angle are 1.865 (3) A and 112.3 (3) degrees , respectively. The Ru(II) ion is displaced out of the C20N4 porphyrin least-squares plane (by 0.2373 A) toward the bridging ligand of the Ci-symmetry dimer. The porphyrin ring systems of the dimer thus exhibit mildly domed conformations.