Carles Miravitlles

Methionine and histidine Pd(II) and Pt(II) complexes: Crystal structures and spectroscopic properties

X-ray crystal structures and properties of the two Pd(II) complexes, [Pd(L-methionine)Cl2] and [Pd(L-histidine)Cl2] and the properties of the corresponding complexes of Pt(II) are described. The amino acids are bound to the metal ion by N (from the NH2 group) and by S in the case of the methionine, or N (from the imidazolic group) in the case of the histidine. Reactions of these compounds with nucleotides have been studied and found to yield several ternary compounds with 5′-GMP and 5′-IMP. In all cases, the Cl− ion has been replaced by one molecule of nucleotide. The metal ion seems to be coordinated to the N(7) atom of the 5′-GMP purine ring and to the N(7) or N(3) of the 5′-IMP purine ring.

Notes. A planar, binucleating, pyrazole derivative ligand. Crystal structure of bis[µ-3,5-bis(2′-pyridyl)pyrazolato-N1N′:N2N″]-bis[dimethanolnickel(II)] dichloride dihydrate

The co-ordinating properties of the ligand 3,5-bis(2-pyridyl)pyrazole (Hbpypz) are reported and complexes of general formulae [M(bpypz)]NO3·xH2O (M = CoII, NiII, CuII, ZnII, or CdII), [M(bpypz)] Cl·xH2O (M = MnII, CoII, NiII, or ZnII), and [M(bpypz)]Br·xH2O (M = CoII NiII or ZnII) are described. The crystal and molecular structure of [Ni2(bpypz)2(MeOH)4]Cl2·2H2O is also reported. The crystals are triclinic, space group P with a= 8.934(3), b= 8.958(6), c= 12.040(5)Aα= 72.02(3), β= 77.66(3), and γ= 68.58(3)°.

Crystal structures and magnetic properties of the mono-µ-halogeno-bridged copper(II) chains Cu(pcpci)X [pcpci =N-(2′-pyridylcarbonyl)pyridine-2-carboximidate, X = Cl or Br]

Compounds Cu(pcpci)Cl (1) and Cu(pcpci)Br (2)[pcpci =N-(2′-pyridylcarbonyl)pyridine-2-carboximidate] are isostructural and crystallize in the monoclinic space group Pc with two formula units in cells of dimensions [(1)/(2)]: a= 3.963(2)/3.888(3), b= 8.48(3)/8.641(3), c= 18.21(12)/17.944(11)A, and β= 94.9(2)/92.63(6)°. The crystal and molecular structure of (2) has been determined by X-ray diffraction methods. Least-squares refinement of 1 351 reflections with I > 2.5σ(I) and 189 parameters gave a final R′= 0.065. The complex exhibits a chain arrangement built up of Cu(pcpci)Br units linked through the bromine atoms. The copper(II) ions are five-co-ordinate and the co-ordination geometry is near square pyramidal. Magnetic susceptibility measurements were analyzed in terms of the Heisenberg model yielding antiferromagnetic exchange interactions of J(1)=–0.4 and J(2)=–0.8 cm–1. These values are discussed on the basis of the structural features and correlated with published magnetostructural data.

Macrocycles incorporating closo- and nido-carbaborane cages: molecular structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane

Reaction of 1,2-dimercapto-1,2-dicarba-closo-dodecaborane under basic conditions with appropriate dihalogenated organic compounds results in the formation of macrocycles incorporating 7,8-dicarbaundecaborate or 1,2-dicarba-closo-dodecaborane units. Polymers are obviated by using high dilution. The crystal structure of 1,2-(3′-oxapentane-1′,5′-dithiolato-SS′)-1′,2′-dicarba-closo-dodecaborane has been determined. It crystallizes in space group P21/a with four formula units in a cell of dimensions a= 11.708(2), b= 10.209(3), c= 12.613(3)A, and β= 109.04(2)°.

Crystal structure and spectroscopic study of [Cu(BPCA)(OH2)(O2CCH3)·H2O complex; BPC = N-2-pyridinylcarbonyl-2-pyridinecarboximidate anion

Abstract The crystal and molecular structure of the [Cu(BPCA)(OH2)(O 2CCH3]·H2O complex (BPCA = N-2-pyridinylcarbonyl-2-pyridinecarboximidate anion) has been determined by X-ray diffraction methods. It crystallizes in the triclinic space group P l with two formula units in a cell of dimensions: a = 7.416(2), b = 8.632(4), c = 13.034(3) A, α = 74.55(3), β = 84.84(3), γ = 81.04(5)°. Least-squares refinement of 2534 reflections with I > 2.5σ(I) and 218 parameters gave a final R = 0.047 and Rw = 0.049. The structure consists of discrete [Cu(BPCA)(OH2)(O2CCH3)] neutral units linked through hydrogen bonding. The coordination geometry around copper ions can be described as tetragonal square pyramidal, the oxygen atom from the coordinated water molecule occupying the axial position. The compound loses both coordinated and lattice water upon heating, and quickly rehydrates to the initial form when it cools down to room temperature. The powder X-band ESR spectra of both the hydrated and the anhydrous forms exhibit the ΔMs = 2 absorption, indicating magnetic exchange between two copper(II) ions. The nature of this coupling is discussed on the basis of the structural features.

DAJUST: a suite of computer programs for pattern matching, space-group determination and intensity extraction from powder diffraction data

DAJUST is the generic name of a software package for powder diffraction formed by the core programs AJUST and SGAID (both written in Fortran) controlled by an easy-to-use Java user interface (DAJUST_UI). While AJUST performs whole-pattern matching (cell-parameter refinement, profile fitting and intensity extraction), SGAID provides a list of the most probable space groups. For the extraction of the integrated intensities, AJUST uses the Le Bail procedure but with a different formula for refining the integrated intensities. Laboratory, synchrotron X-ray and neutron sources, and both reflection and transmission experimental geometries, are supported. Other program options include automated background estimation, asymmetry correction, and corrections for absorption, variable divergence and/or illumination. The extracted intensity data are written in text format and can be directly processed by the direct methods program XLENS [Rius (2011). Acta Cryst. A67, 63–67] and the multisolution direct-space structure determination program TALP [Vallcorba, Rius, Frontera & Miravitlles (2011). Acta Cryst. A67, C272].

Silver(I), mercury(II) and copper(I) complexes of acyclic and macrocyclic dithioether, metaxylyl based ligands

Abstract The compounds [HgL 1 (NO 3 ) χ ] (L 1 = 6-oxa-3,9-dithiabicyclo[9,3,1] pentadeca-l(15),11,13-triene) ( 1 ), [AgL 2 (NO 3 )} χ ] (L 2 = (1,3-bis(phenylthio)methyl) benzene) ( 2 ), [HgL 3 Cl 2 2 ] and [CuL 3 Cl} χ ] (L 3 = (1,3-Bis(ethylthio)methyl)benzene) ( 3 ) and ( 4 ) have been synthesized and their structures determined by X-ray crystallography. Compounds ( 1 ) and ( 2 ) have linear polymeric chains of alternating trigonal silver(I) cations and bridging ligands bonded through the sulfur atoms. In both structures the nitrate anion retains coordination to the silver atom. Compound ( 3 ) is a dimeric complex. Each mercury(II) cation is bound to two bridging chlorine atoms, one terminal chlorine atom and one sulfur atom from the ligand. Compound ( 4 ) is a threedimensional polymer. Each Cu 1 cation has a distorted tetrahedral environment defined by two sulfur atoms of different L 3 ligands and two bridging chlorine atoms. In each case the dithioether ligand acts as a bridging or monodentate ligand and does not chelate the metal.

exo-Dithio and monothio carborane derivatives: a mechanism for their partial degradation. Molecular structure of tetramethylammonium 7,8-(3′,6′,9′-trioxaundecane-1′, 11′-dithiolato-SS′)-7,8-dicarba-nido-undecaborate

Abstract The reaction of 1,2-dithiol-o-carborane, under basic conditions, with appropriate organic dihalogenated compounds results in the formation of macrocycles incorporating 7,8-dicarba-nido-undecaborate or 1,2- dicarba-closo-dodecaborane units. The synthesis of some non-cyclic dicarborane compounds containing only one sulfur per cage directly bonded to the cluster is described. On the basis of the different behavior of the dithiolato compounds versus the monothiolato, a mechanism that explains the formation of partially degraded and non-degraded compounds is proposed. The molecular structure of tetramethylammonium 7,8-(3′,6′,9′-trioxaundecane-1′,11′ -dithiolato-SS′)-dicarba-nido-undecaborate has been determined. It crystallizes in space group P21/c with 4 formula units per cell. The cell dimensions are a=14.058(7), b=7.536(2), c=22.980(9) A, β=99.41°.

X-ray diffraction structure of a ternary copper(II) peptide complex (benzimidazole) (glycylglycinato) copper(II) trihydrate

Abstract A new ternary complex [Cu(gg)(bzim)]·3H 2 O ( 1 ) (gg = glycylglycine(2−), bzim = benzimidazole) has been crystallized from aqueous solution. The coordination geometry about the copper is approximately square planar with the tridentate glycylglycine dianion and the N(1) of the benzimidazole ligand occupying the corners of the square. The plane of the bzim ligand is twisted 19.0(1)° from the square plane. IR and electronic spectral data of the compound are discussed and related to the binding mode derived from the crystal structure determination. The three water molecules are involved in a hydrogen bonding network.

Synthesis and characterization of cyclometallated complexes of benzalazines. Crystal and molecular structure of [{Pd(p-ClC6H3CHN–)Cl(PEt3)2}2]

The reaction of benzalazines, (p-RC6H4CHN–)2(R = H, Cl, NO2, or NMe2), with PdCl2 leads in the the first two cases to the formation of cyclometallated polymeric species that react with phosphines to yield dimetallated compounds [{Pd(p-RC6H3CHN–)Cl(PR′3)2}2](R′= Et or Ph) and/or [{[graphic omitted]–)Cl(PPh3)}2]. Phosphine exchange reactions give the complex [{Pd(p-RC6H3CHN–)Cl(PEt3)(PPh3)}2]. The molecular structure of [{Pd(p-ClC6H3CHN–)Cl(PEt3)2}2] has been determined by a single-crystal X-ray analysis. The crystals are monoclinic, space group P21/n, a= 11.124(3), b= 10.062(2), c= 22.566(5)A, β= 102.95(3)°, and Z= 2; R= 0.052 for 3 306 reflections. Palladium atoms are five-co-ordinated, the Pd–N distance being 2.743 A. However, n.m.r. spectra show that, in solution, free rotation around the C(aromatic)–C(azomethine) bonds does occur even at –100 °C.