X. Solans

Crystal structure and magnetic properties of [Ni(terpy)(N3)2]2.2H2O, a nickel(II) dinuclear complex with ferromagnetic interaction

Abstract The crystal structure of dimeric [Ni(C15H11N3)(N3)2]2·2H2O has been determined at room temperature. Crystal data are as follows: P21/a, Z=2, a=15.628(3), b=9.798(2), c=10.322(2) A, β=92.32(2)°, R=0.049 for 1137 reflections. The complex consists of isolated centrosymmetric [Ni(terpy)(N3)2]2·2H2O dimeric units, where the two metallic centers are linked through the N-end of two azide bridging groups. The Ni(II) atom displays a distorted octahedral coordination, being linked to three N atoms from the terpyridine ligand and three N atoms of three azide ligands. Magnetic susceptibility measurements have shown the existence of ferromagnetic exchange between nickel centers (J=+20.1 cm−1, D=−12.5 cm−1). The magnetic behavior of this and others related complexes is discussed and some magneto-structural trends are given.

Structural and cytotoxic study of new Pt(II) and Pd(II) complexes with the bi-heterocyclic ligand mepirizole

Pd(II) and Pt(II) complexes of formulae [MLCl2], where L = mepirizole, were synthesized and characterized. Two complexes were obtained and studied by different techniques: IR, 1H and 13C NMR and XPS spectroscopies and mass spectrometry (electrospray). The crystal structure of the complex cis-dichloro-4-methoxy-2-(5-methoxy-3-methyl- pyrazol-1-yl)-6-methyl-pyrimidinepalladium(II), [Pd(mep)Cl2], was studied by crystal X-ray diffraction. It consists of discrete molecules with planar geometry. Pd(II) ions are four-coordinated by two mepirizole nitrogen atoms (N1 from the pyrazole ring and N4 from the pyrimidine ring) and two chlorine atoms. The geometry of the PdN2Cl2 chromophore is a distortion of the square-planar coordination. Data from powder pattern X-ray diffraction of cis-dichloro-4-methoxy-2-(5-methoxy-3-methyl-pyrazol-1-yl)-6-methyl- pyrimidineplatinum(II), [Pt(mep)Cl2], demonstrated that the two complexes are isostructural. The cytotoxic activity of both Pd and Pt complexes was checked for six different tumor cell lines and was lower than that of cisplatin. The Pt bound to DNA was also checked and only a low percentage is able to cross the cell membrane.

Preparation and characterization of the dichromates of the organic bases: 2,4′-bipyridine, 2,2′-dipyridylamine and 4,4′-bipyridine

Abstract Dichromates of 2,4′-bipyridine (two forms), [(H2-2,4′-bipy)(Cr2O7)] (1) and [(H-2,4′-bipy)2(Cr2O7)] (2), 2,2′-dipyridylamine, [(H-dpam)2(Cr2O7)] (3), and 4,4′-bipyridine (two forms), [(H2-4,4′-bipy)(Cr2O7)] (4) and [(H-4,4′-bipy)2(H2-4,4′-bipy)(Cr2O7)2] (5), were prepared by reaction of chromium(VI) oxide with the free organic bases in the appropriate stoichiometric ratio in water at 25°C. The structures of compounds 2, 3 and 4 were determined by X-ray crystallography and revealed the existence of discrete dichromate anions formed by two tetrahedral CrO4 groups joined through shared O atoms, and the respective protonated organic bases hydrogen bonded to respective dinegative anions. A short CH…O interaction [2.996(4) A] between the organic cation and the dichromate anion was observed in compound 4. All organic dichromates were also characterized by IR, UV-vis 1H NMR measurements. For compounds 2, 3 and 4, a comparison was made and the crystallographic data of a series of mono- and polychromates and showed a correlation of the terminal and bridging CrO atomic distances with an increasing degree of polymerization. A graph theory cluster expansion was employed for these correlation studies.

Synthesis of mono and binuclear carbonyl complexes of manganese with cyanide or thiocyanate ligands. X-ray crystal structure of [{fac-Mn(CO)3(phen)}2(μ-CN)]PF6

Abstract The neutral complexes cis-trans-[MnX(CO)2(bipy)- (P(OPh)3)] (X=I, CN or SCN) have been prepared by nucleophilic substitution of P(OPh)3 by X− in the cationic complex cis-trans-[Mn(CO)2(bipy)- (P(OPh)3)2]+, or, in the case of X=CN, by reacting the iodo-dicarbonyl with AgCN. The cyanide complex reacts with MeI in the presence of KPF6 or with HBF4{dEt2O (of BF3}dEt2O) to give respectively the cationic CNMe or the neutral CNBFF3 derivative. The cyanide species fac-[Mn(CN)(CO)3( N N )] ( N N =bipy or phen) and cis-trans-[Mn(CN)(CO)2(bipy)(P(OPh)3)] react at room temperature with fac- [MnBr(CO)3( N N )] or cis-trans-[MnI(CO)2(bipy) P(OPh)3)] in the presence of TlPF6 to give the corresponding cationic cyanide-bridged complexes [{Mn}aCN{Mn}b]+ for {Mn}a or {Mn}b  Mn(CO)3( N N ) or Mn(CO)2(bipy)(P(OPh)3). In the same way the salt [fac-Mn(CO)3(bipy)2(/μ-SCN)]- PF6 can be prepared from fac-[Mn(NCSXCO)3(bipy)] and fac-[MnBr(CO)3(bipy)]. The structure of the compound [fac-Mn(CO)3(phen)2(μ-CN)]PF6 has been established by X-ray diffraction. The reaction of the cyanide bridged complexes with HBF4·Et2O is also discussed.

Platinum(II) substituted pyrrolidine complexes. Crystal structure of dichloride 1,2 diethyl 3 aminopyrrolidine PtII. Reactions with DNA and dinucleotides

Abstract The effect of five derivatives of PtII, cis dichloro-(1,2-dimethyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1-methyl, 2-ethyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1-ethyl, 2-methyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1,2-diethyl-3-aminopyrrolidine)platinum(II), and cis dichloro-(1-propyl, 2 methyl-3 aminopyrrolidine)platinum(II) on platination of DNA was studied by CD and melting temperature determination. Reactions with the nucleotides d(ApG) and d(ApA) were also followed by 1H NMR and CD, indicating binding via N(7) and formation mainly of bifunctional, in the case of d(ApG), or monofunctional adducts, in the case of d(ApA). The crystal structure of cis dichloro-(1 ethyl, 2 methyl-3 aminopyrrolidine)platinum(II) shows the analogues cisplatin structure of these active antitumour complexes. This compound is racemic.

Coordination behaviour of methazolamide [N(-4-methyl-2-sulfamoyl-Δ2-1,3,4-thiadiazolin-5-ylidene)] acetamide, an inhibitor of carbonic anhydrase enzyme. Synthesis, crystal structure and properties of bis(methazolamidate)tetrammine nickel(II)

Abstract The interaction of methazolamide (Hmacm) with Ni(II) ion and ammonia molecules gives rise to the complex of formula [Ni(macm)2(NH3)4]. The complex crystallizes in the monoclinic P21/n space group with a = 14.255(4), b = 7.126(2), c = 12.444(3) A, β = 113.12(3)° and Z = 2. The structure was refined to R = 0.065 (Rw = 0.065). The complex consists of monomeric units which interact through hydrogen bonds and van der Waals contacts. The Ni(II) ion is coordinated with the deprotonated sulfonamido nitrogen of the macm− ligand in axial sites and the ammonia molecules in equatorial positions. IR, electronic spectra and 1H NMR results are also reported.

Structure and properties of Cu(II)(o-hydroxypropiophenone-salicylhydrazide)(2,2′-bipyridyl) [Cu(OHP-SHZ)(bipy)] and Cu(II)(o-hydroxypropiophenone-salicylhydrazide)(2,2′-bipyridylamine) monohydrate [Cu(OHP-SHZ)(bipyam)]H2O

Abstract The preparation of stable Lewis base adducts of CuL (H2L=Schiff base derived from the condensation of o-hydroxypropiophenone (OHP) and salicylhydrazide (SHZ)) is described. The N-donors bipy and bipyam ligands (bipy=2,2′-bipyridyl; bipyam=2,2′-bipyridylamine) give the complexes [Cu(OHP-SHZ)(bipy)] (I) and [Cu(OHP-SHZ)(bipyam)]H2O (II) which have been characterized by physical and spectroscopic techniques. Crystals of I are orthorhombic, space group Pcab, with a=10.221(3), b=12.643(3), c=35.448(3) A, V=4581(2) A3 and Z=8. The structure of complex I is shown to comprise discrete monomeric [Cu(OHP-SHZ)(bipy)] molecules in which the Cu(II) atom environment exhibits a highly distorted five-coordinated geometry. Crystals of II are monoclinic, space group C2/c, with a=24.804(3), b=13.231(3), c=14.739(3) A, β=99.57(2)°, V=4770(2) A3 and Z=8. The structure of this complex consists of discrete entities associated into H-bonded binuclear units via the lattice water molecules. The coordination sphere around the copper center is nearly square pyramidal. The transition from a six-membered chelated ring to a five-membered one results in a less distorted coordination polyhedron around the Cu(II) ion. In both complexes the OHP-SHZ ligand occupies three of the coordination sites through the same (ONO) donor atoms while the remaining positions are occupied by the pyridine N atoms. EPR spectra provide evidence of the existence of very weak magnetic exchange coupling in the complex [Cu(OHP-SHZ)(bipyam)]H2O (II). Thermogravimetric and differential scanning calorimetric studies of complex I show that this complex loses the bipy molecule through an endothermic process with ΔH=81.75 kJ mol−1. The best kinetic parameter values corresponding to the process involving the loss of the bipy molecule were found on the basis of the agreement between non-isothermal and isothermal methods and are given by the Abou-Shaaban–Simonelli equation in isothermal conditions. The better representation of the reaction mechanism is the phase-boundary, spherical symmetry reaction.

Pd(II) and Pt(II) complexes with 2-(ethylthio)ethylamine. Crystal structure of [Pd(2-(ethylthio)ethylamine)Cl2] and [Pd(2-(ethylthio)ethylamine)2](ClO4)2

Abstract Two Pd(II) complexes and two Pt(II) complexes of formula [PdLCl2], [PdL2](ClO4)2, [PtLCl2] and [Pt2L2Cl2]Cl2, respectively, where L=ethylthioethylamine, were synthesized and characterized by the usual spectroscopic techniques. Crystal structures of the palladium complexes were determined by X-ray diffraction. The ligand binds to the metal ion in bidentate fashion through the sulfur and nitrogen atoms, in both cases. The reactivity of the complexes with calf thymus and pBR322 plasmid DNA was studied by CD and electrophoretic mobility respectively. No changes affecting the secondary or tertiary DNA structure were observed.

Neutral and cationic carbonyl complexes of manganese with tetramethylthiourea. Crystal structure of cis-{Mn(CO)4(SC[N(CH3)2]2)2} CIO4

Abstract Tetramethylthiourea (TMTU) reacts with Mn 2 (CO) 10 in hexane under UV irradiation to give axial Mn 2 (CO) 9 (TMTU), with MnBr(CO) 5 in CH 2 Cl 2 at room temperature to give cis -MnBr(CO) 4 (TMTU), and with Mn(OClO 3 (CO) 5 in CH 2 Cl 2 to give the cationic tetracarbonyl cis -[Mn(CO) 4 (TMTU) 2 ]CIO 4 . The last complex has been characterized by X-ray diffraction; it reacts with more (TMTU) to give the unstable species fac -[Mn(CO) 3 (TMTU) 3 ]ClO 4 , with pyridine to give fac -[Mn(CO) 3 (PY) 2 (TMTU)]ClO 4 , and with the bidentate ligands o -phenanthroline or bis-diphenylphosphinomethane to give the corresponding cationic fac -tricabonyls fac -[Mn(CO) 3 (TMTU)]ClO 4 . In all the complexes prepared the TMTU ligand is S -bonded to the manganese.

Reactions of Ru(HCCHR)Cl(CO)(PPh3)2 with functionalized carboxylates. Crystal structure of Ru(HCCHPh)(O2CCHCHCHCHCH3)(CO)(PPh3)2

Abstract The coordinatively unsaturated 16-electron complexes Ru(HCCHR)Cl(CO)(PPh3)2 (RtBu and Ph) react with the sodium salts of functionalized carboxylates NaO2CR′ (R′MeCHCHCHCH, CH2CHCH2, PhCC and MeCC) to give saturated complexes of formulae Ru(HCCHR)(O2CR′)(CO)(PPh3)2, where the carboxylate group acts as an η2-coordinated ligand. The structure of the complex Ru(HCCHPh)(O2CCHCHCHCHCH3)(CO)(PPh3)2 has been determined by X-ray diffraction. Crystals are monoclinic, space group P21/n with dimensions of the unit cell of a = 12.191(3), b = 18.596(4), c = 20.001(4) A , β = 107.23(3)° and Dx = 1.331 g cm−3 for Z = 4. All the complexes have been identified by IR, 1H NMR and 31P NMR spectroscopies, and from their C and H elemental analyses.