John H. Thurston

Synthesis and characterization of platinum(II) and (IV) complexes containing hexamethyleneimine ligand: crystal structure of [PtII(hexamethyleneimine)2(cyclobutanedicarboxylato)]·H2O

Abstract A series of new platinum(II) and platinum(IV) complexes of the type [PtII(HMI)2X] (where HMI=hexamethyleneimine, X=dichloro, sulfato, 1,1-cyclobutanedicarboxylato [CBDCA], oxalato, methylmalonato, or tatronato) and [PtIV(HMI)2Y2Cl2] (where Y=hydroxo, acetato, or chloro) were synthesized and characterized by infrared (IR) spectroscopy, 13C and 195Pt nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Among the complexes synthesized, [PtII(hexamethyleneimine)2(1,1-cyclobutanedicarboxylato)]·H2O was examined by single-crystal X-ray diffraction. The slightly distorted square planar coordination environment of the platinum metal includes the amino group of the hexamethyleneimine (HMI) molecule and the oxygen atoms of the carboxylato ligand. The cyclobutanedicarboxylic acid (CBDCA) molecule adopts six-member chelating rings with platinum. Hydrogen bonding plays an important part in holding the crystal lattice together.

Preparation, characterization, and antitumor activity of new cisplatin analogues with 1-methyl-4-(methylamino)piperidine: crystal structure of [PtII(1-methyl-4-(methylamino) piperidine)(oxalate)].

A series of new platinum(II) complexes of the type [Pt(II)(mmap)X] (where mmap, 1-methyl-4-(methylamino)piperidine and X, 1,1-cyclobutanedicarboxylato (CBDCA), oxalato, malonato, methylmalonato, dimethylmalonato, ethylmalonato, diethylmalonato or 2,3-naphthalene dicarboxylato (NDCA)) have been synthesized and characterized by elemental analysis, infrared (IR), and 13C and 195Pt nuclear magnetic resonance (NMR) spectroscopy. The crystal structure of the analogue [Pt(II)(mmap)(oxalate)] was determined using the single crystal X-ray diffraction method. Based upon a total of 4964 collected reflections, we determined that the compound crystallizes in the monoclinic space group P2(1)/c (with a=11.890(2) A, b=9.6695(19) A, c=9.875(2) A, beta=102.03(3) degrees, Z=4, and R=0.0428). In this complex, platinum has a slightly distorted square planar geometry with the two adjacent corners being occupied by two nitrogen atoms of the mmap ligand, whereas the remaining cis positions are occupied by two oxygen atoms of the oxalate molecule. The mmap ligand is in a boat conformation and forms six-membered chelating rings as well as the oxalate molecule forms five-membered chelating rings with platinum. The complexes were evaluated for their cytotoxic potential against the sensitive A2780 tumor model and cisplatin-resistant clone derived in vitro from potential cells.

Selective Arylation Reactions of Bismuth-Transition Metal Salicylate Complexes

Heterometallic bismuth-niobium or -tantalum salicylate complexes react with sodium tetraphenylborate to produce complexes in which one or more aryl groups have been transferred from boron to bismuth with the concomitant displacement of a eta(2)-salicylato ligand. When the previously reported Bi(2)Ta(2)(sal)(4)(Hsal)(4)(OEt)(4) (1) and BiTa(4)(mu-O)(4)(sal)(4)(Hsal)(3)(O(i)Pr)(4) (2) are treated with an alcoholic solution of NaBPh(4), the compounds [PhBi(Hsal)Ta(sal)(2)(OEt)(2) x EtOH](2) (3) and PhBiTa(4)(mu-O)(4)(Hsal)(2)(sal)(4)(OEt)(4) x CH(2)Cl(2) (4) are produced (sal = O(2)CC(6)H(4)-2-O(2-), Hsal = O(2)CC(6)H(4)-2-OH(-)). The core geometries of the heterometallic complexes are retained. However, if preparations of compound 1 are treated with NaBPh(4) without prior isolation of 1, [Ph(2)BiNb(sal)(2)(OMe)(2)](infinity) (5) is produced instead. This compound was characterized both as a solvent-free crystalline form and as one containing a lattice diethyl ether. The compound exhibits a polymeric chain structure that can be viewed as alternating [Ph(2)Bi](+) and [Nb(sal)(2)(OMe)(2)](-) units connected via bridging carboxylate groups. The arylation of the bismuth(III) center proceeds smoothly under mild conditions at room temperature, affording a new means for the mild functionalization of bismuth-transition metal heterometallic complexes.

Synthesis and characterization of cis-bis-heptamethyleneimine platinum(II) dicarboxylate complexes: crystal structure of cis-[Pt(heptamethyleneimine)2(malonate)]·H2O

Abstract A series of new platinum complexes of the type cis-[Pt(L)2X] (where L=heptamethyleneimine and X=1,1-cyclobutanedicarboxylate (CBDCA), oxalate, malonate, methylmalonate, ethylmalonate, dimethylmalonate, or diethylmalonate ligand) were synthesized and characterized by elemental analysis, infrared, and 195Pt nuclear magnetic resonance spectroscopy. The crystal structure of cis-[Pt(L)2(malonate)]·H2O was determined by X-ray crystallography. In all of the molecules, the platinum atom adopts a distorted square-planar geometry. Two of the coordination sites of the metal center are occupied by heptamethyleneimine ligands, which are arranged in a cis orientation. The coordination sphere of the metal is completed through interaction of the platinum with two of the oxygen atoms of the malonate ligand, resulting in the formation of a six-membered chelate ring. In the solid state, an intricate network of hydrogen bonds is found to exist between carbonyl oxygen atoms, amine hydrogen atoms and included solvent water.

Homopiperazine platinum(II) complexes containing substituted disulfide groups: crystal structure of [PtII(homopiperazine)(diphenylsulfide)Cl]NO3

Abstract A series of new cationic platinum(II) complexes of the type [Pt(L)(R′R″S)Cl]NO3 (where L=homopiperazine or 1-methylhomopiperazine and R′R″S=dimethylsulfide, diethylsulfide, dipropylsulfide, diisopropylsulfide, dibutylsulfide, diphenylsulfide, dibenzylsulfide, methylphenylsulfide, or methyl p-tolylsulfide) were synthesized and characterized by elemental analysis and infrared, 1H and 195Pt nuclear magnetic resonance spectroscopy. Among the complexes synthesized, [PtII(homopiperazine)(diphenylsulfide)Cl]NO3 was examined by single-crystal X-ray diffraction. The slightly distorted square plane of the platinum complex included the amino groups of the homopiperazine molecule in a cis orientation, the sulfur atom of diphenyl sulfide, and a chloride ion. The homopiperazine molecule adopts a boat conformation and forms five- and six-membered chelating rings with platinum. Hydrogen bonding plays an important part in holding the crystal together.

Towards a molecular model for bismuth(III) subsalicylate. Synthesis and solid-state structure of [Bi(Hsal)3(bipy)(C7H8]2 and [Bi(Hsal)(sal)(1,10-phenanthroline)(C7H8]2

The synthesis and characterization of the first bismuth salicylate complexes, stabilized by chelating amine ligands, offers the possibility for detailed investigation of molecular precursors of the biologically significant compound bismuth subsalicylate (BSS).