Mahmoud M. Al-Ktaifani

Synthesis and crystal and molecular structures of N,N′-methylenedipyridinium tetrachlorozincate(II) and N,N′-methylenedipyridinium tetrachlorocadmate(II)

Treatment of N,N′-methylenedipyridinium dichloride [C5H5N-CH2-NC5H5]Cl2 with MCl2 (M = Zn or Cd) in aqueous solution gives the organic-inorganic hybrid ionic compounds [C5H5N-CH2-NC5H5] · [MCl4]. Both complex salts were fully characterised by multinuclear NMR spectroscopy, elemental analysis, and their molecular structures confirmed by powder X-ray diffraction studies. The most striking feature in both solid state structures was the presence of the C…Cl-M short contacts between the organic [C5H5N-CH2-NC5H5] dication and inorganic [MCl4] anion, which led to different crystal packing. For [C5H5N-CH2-NC5H5]·[ZnCl4], the C…Cl-Zn interactions led to the alternating arrangement of [C5H5N-CH2-NC5H5]2+[ZnCl4]2− to form 1-D chains in the direction [010], and each individual chain had a two-fold rotational axis along the b axis, while for [C5H5N-CH2-NC5H5] · [CdCl4] the C…Cl-Cd associations gave 2-D network. In both solid state structures, the presence of Cl-ring centroid distances gave a strong indication of some form of Cl-π interactions.

Saccharomyces cerevisiae SHSY detoxifies petroleum n-alkanes by an induced CYP52A58 and an enhanced order in cell surface hydrophobicity.

Environmental hydrocarbon contamination has a serious hazard to human health. Alkanes, the major component of hydrocarbons, can be consumed by various species of yeast. We previously identified a new strain SHSY of Saccharomyces cerevisiae with a remarkable ability to utilize the petroleum crude-oil (PCO) in aqueous solution. The current study demonstrated that the n-alkanes-assimilation activity of S. cerevisiae SHSY was related to an induced microsomal protein of 59 kDa approximately. The identified ORF encoded a protein of 517 amino acids and shared 93% sequence identity with an alkane-inducible hydroxylase CYP52A53 isolated from Scheffersomyces stipitis CBS. It was therefore referred as CYP52A58. The catalytic activity of the recombinant CYP52A58 was confirmed by the hydroxylation of n-alkanes, it showed an optimal mono-terminal hydroxylation activity toward n-hexadecane. Moreover, the ability of the yeast to use n-alkanes was accompanied with an increasing level in cell wall mannoproteins. Two differential protein bands were detected in the mannoproteins extracted from PCO-grown yeast. In parallel, a significant increase in the fatty acids content with a high degree of unsaturation was subsequently detected in the PCO-grown yeast. This study characterizes a safe and potential microorganism to remove n-alkanes from the aquatic environment.

2-(Benzoylsulfanyl)acetic acid and 2,5-dioxopyrrolidin-1-yl 2-(benzoylsulfanyl)acetate by powder X-ray diffraction studies.

The structures of the title compounds, C(9)H(8)O(3)S, (I), and C(13)H(11)NO(5)S, (II), were determined by X-ray powder diffraction. Both were solved using the direct-space parallel tempering algorithm and refined using the Rietveld method. In (I), the C-S-C bond angle is slightly smaller than normal, indicating more p character in the bonding orbitals of the S atom. The carboxylic acid group joins across an inversion centre to form a dimer. The crystal packing includes a weak C-H···O hydrogen bond between an aromatic C-H group and a carboxylic acid O atom to form a two-dimensional network parallel to (10 ̅1). The C-S-C bond angle in (II) is larger than its counterpart in (I), indicating that the S atom of (II) has less p character in its bonding orbitals than that of (I), according to Bents rule. The crystal structure of (II) includes weak C-H···O hydrogen bonds between the H atoms of the methylene groups and carbonyl O atoms, forming a three-dimensional network.

N,N′-methylenedipyridinium Pt(II) and Pt(IV) hybrid salts: synthesis, crystal and molecular structures of [(C5H5N)2CH2] · [PtCl4] and [(C5H5N)2CH2] · [PtCl6]

The highly insoluble organic-inorganic hybrid ionic compounds N,N′-methylenedipyridinium tetrachloroplatinate(II) [(C5H5N)2CH2] · [PtCl4] and N,N′-methylenedipyridinium hexachloroplatinate(IV) [(C5H5N)2CH2] · [PtCl6] were obtained by the treatment of N,N′-methylenedipyridinium dichloride monohydrate [(C5H5N)2CH2]Cl2 · H2O with K2[PtCl4] or (NH4)2[PtCl6], respectively, in an aqueous solution. Both complexes were isolated, purified, characterised by elemental analysis, and their molecular structures were confirmed by powder X-ray diffraction. The crystal structure of both compounds consists of separated discrete dications [(C5H5N)2CH2]2+ and anions [PtCln]2− (n = 4 or 6). As anticipated, the dications formed a butterfly shape consisting of two pyridine rings bound to the methylene group via their N atoms, while the Pt centre had a square planar geometry in [(C5H5N)2CH2] · [PtCl4] and an octahedral coordination in [(C5H5N)2CH2] · [PtCl6]. Interestingly, both crystal structures are stabilised by intermolecular C-H…Cl non-standard hydrogen bonds, π-π ring interactions between two pyridine rings of adjacent dications, and also by Cl-π interactions.

Powder X-ray investigation of 4,4'-diisocyano-3,3'-dimethyl-biphen-yl.

The title compound, C16H12N2, was investigated in a powder diffraction study and its structure refined utilizing the Rietveld Method. The molecule has approximate C2 symmetry. The dihedral angle between the rings is 25.6 (7)°. The crystal packing is consolidated by weak C—H⋯C N hydrogen-bond-like contacts, which lead to the formation of a three-dimensional network. Further stabilization of the crystal structure is achived by weak non-covalent π–π interactions between aromatic rings, with a centroid–centroid distance of 3.839 (8) Å.

Powder study of poly[(μ2-2,2-dimethylpropane-1,3-diyl diisocyanide)-μ2-iodido-silver(I)]

In order to explore the chemistry of the bidentate ligand 2,2-dimethylpropane-1,3-diyl diisocyanide and to investigate the effect of counter-ions on the polymeric structure of (2,2-dimethylpropane-1,3-diyl diisocyanide)silver(I) complexes, the title polymeric compound, [AgI(C(7)H(10)N(2))](n), was synthesized by treatment of 2,2-dimethylpropane-1,3-diyl diisocyanide with AgI. X-ray powder diffraction studies show, as expected, a polymeric structure, similar to the very recently reported Cl(-) and NO(3)(-) analogues [AgX(C(7)H(10)N(2))](n) (X = Cl(-) or NO(3)(-)). In the title structure, the Ag(I) centre is bridged to two adjacent Ag(I) neighbours by bidentate 2,2-dimethylpropane-1,3-diyl diisocyanide ligands via the NC groups to form [Ag{CNCH(2)C(CH(3))(2)CH(2)NC}](n) chains. The iodide counter-ions crosslink the Ag(I) centres of the chains to form a two-dimensional polymeric {[Ag{CNCH(2)C(CH(3))(2)CH(2)NC}]I}(n) network. This study also shows that this bidentate ligand forms similar polymeric structures on treatment with AgX, regardless of the nature of the counter-ion X(-), and also has a strong tendency to form polymeric complexes rather than dimeric or trimeric ones.

Poly[μ-bromido-μ-(2,2-dimethyl­propane-1,3-diyl diisocyanide)-silver(I)]: a powder diffraction study

In the title compound, [AgBr(C7H10N2)]n, adjacent Ag(I) atoms are bridged by bidentate CNCH2C(CH3)2CH2NC ligands via the NC groups, forming [Ag{CNCH2C(CH3)2CH2NC}]n chains with the metal atom in a distorted tetrahedral coordination. The bromide counter-anions cross-link the Ag(I) atoms of the chains, forming a two-dimensional polymeric network {[AgI(CNCH2C(CH3)2CH2NC)]Br}n extending parallel to (010). The polymeric structure is similar to that of the very recently reported Cl−, I− and NO3 − analogues. This gives a strong indication that 2,2-dimethylpropane-1,3-diyl diisocyanide is a potential ligand for giving polymeric structures on treatment with AgX (X = Cl−, Br−, I− or NO3 −) regardless of the counter-anion used.

Synthesis of 2-methyl-2-propoxypropyl isocyanide and its Cu(I) tetraflouroborate complex

Abstract2-Methyl-2-propoxypropyl isocyanide [CNCH2C(OPr)(CH3)2] and its Cu(I) tetrafluoroborate complex [Cu{CNCH2C(OPr)(CH3)2}4]BF4 were prepared in good yields and purities. Both compounds were fully characterized by IR and NMR spectroscopy.

Poly[(μ2-2,2-dimethylpropane-1,3-diyl diisocyanide)-μ2-nitrato-silver(I)]: a powder study

In order to investigate the effect of counter-anions on the polymeric structure of (2,2-dimethylpropane-1,3-diyl diisocyanide)silver(I) complexes, the novel title polymeric compound, [Ag(NO(3))(C(7)H(10)N(2))](n), has been synthesized. The crystal structure was determined by simulated annealing from X-ray powder diffraction data collected at room temperature. The current structure is similar to the recently reported structure of the analogue with chloride replacing nitrate. This study illustrates that both the chloride and nitrate complexes crystallize in the orthorhombic system in the Pbca space group with one monomer in the asymmetric unit, and also gives a strong indication that the counter-anion does not have a considerable effect on the polymeric structure of the complex. The Ag centre lies in a distorted tetrahedral environment and is bonded to two 2,2-dimethylpropane-1,3-diyl diisocyanide ligands to form chains. The nitrate anions crosslink the Ag centres of the chains to form a two-dimensional polymeric network structure.