HO Hydrogen Bonds (ho + hydrogen_bond)

Distribution by Scientific Domains


Selected Abstracts


"Tail,Tail Dimerization" of Ferrocene Amino Acid Derivatives

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2010
Daniel Siebler
Abstract Acid anhydrides of N-protected 1,-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a,4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N,HO hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N,HO hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication across the anhydride moiety is found to be very weak as judged from electrochemical, spectroscopic, and theoretical experiments. [source]


Synthesis and Molecular Structures of Nickel(II) and Cobalt(III) Complexes with 2-(Arylimino)-3-(hydroxyimino)butane

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2003
Ennio Zangrando
Abstract We report new series of NiII and CoIII complexes with nitrogen-donor chelating ligands of the (E,E)-2-(arylimino)-3-(hydroxyimino)butane type (Ar,N,N,OH). These ligands are characterized by a hydrophilic (OH group) and a hydrophobic region (aryl group). NiII derivatives were obtained either as trimers of formula [Ni3(Ar,N,N,OH)3Br4(OH)][Br], with the hydrophobic groups oriented on the same side, or as bis(chelated) derivatives with cis geometry, depending on the steric hindrance of the aryl groups. CoIII complexes were obtained only as bis(chelated) derivatives, with the two ligands coplanar. The "iso -oriented" arrangement of ligands in bis(chelated) CoIII complexes is favored by weak interactions between the two ligands, namely O,HO hydrogen bond and stacking interactions between the aryl groups. CoIII complexes might find application as catalysts for living or controlled radical polymerization of polar olefins, and preliminary results are reported. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source]


Structural characterization of p -benzosemiquinone radical in a solid state: the radical stabilization by a low-barrier hydrogen bond

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2006
imir Mol
Semiquinone (p -benzosemiquinone), a transient organic radical, was detected in the solid state by EPR spectroscopy revealing four symmetrically equivalent protons. A variable-temperature X-ray diffraction analysis (293 and 90,K) and EPR data support a dynamical disorder of the proton. A low-barrier O,HO hydrogen bond stabilizes the radical. The C,O bond length is 1.297,(4),, corresponding to a bond order of ca 1.5. The geometry of the radical implies an electron delocalization throughout the benzenoid ring. Two polymorphs of semiquinone, monoclinic and triclinic, were observed and their structures determined. Their crystal packings were compared with those of quinhydrone polymorphs. [source]


"Tail,Tail Dimerization" of Ferrocene Amino Acid Derivatives

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 25 2010
Daniel Siebler
Abstract Acid anhydrides of N-protected 1,-aminoferrocene-1-carboxylic acid (Fca) have been prepared and spectroscopically characterized (protection group Boc, Fmoc, Ac; 4a,4c). The structure of the Boc-derivative 4a has been determined by single-crystal X-ray crystallography. An intramolecular N,HO hydrogen bond involving the carbamate units results in a ring structure containing the two ferrocene units, the anhydride moiety, and the hydrogen bond. In the crystal, the individual molecules are connected by intermolecular N,HO hydrogen bonds of the carbamate unit. Experimental and theoretical studies suggest that the ring motif is also a dominant species in solution. Electronic communication across the anhydride moiety is found to be very weak as judged from electrochemical, spectroscopic, and theoretical experiments. [source]


A CuIINiII Complex with Ethylenediamine: Crystal Structure and Ferromagnetic Behaviour of an Aqua-Bridged Heterometallic Chain Containing Ambidentate Ni(OAc)42, Blocks

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2010
Oksana V. Nesterova
Abstract A one-pot reaction of copper powder and nickel and ammonium acetates in a CH3OH solution of ethylenediamine (en) yields a unique 1D aqua-bridged polymer [Cu(en)2(,2 -H2O)2Ni(OAc)4]n4nH2O (1) with an ambidentate Ni(OAc)42, fragment that has not been previously characterized. The basic structural motif of 1 contains a previously unreported heterometallic M(,2 -H2O)M, aqua-bridge chain with alternating metal atoms. A complex system of N/O,HO hydrogen bonds strengthens the polymeric chains and links them into a supramolecular three-dimensional network. Variable-temperature magnetic susceptibility measurements of 1 revealed a weak ferromagnetic coupling (J = 1.1 cm,1) between the paramagnetic copper(II) and nickel(II) ions, which is transmitted through the oxygen bridges. [source]


Tellurated Schiff Bases Formed from {2-[(4-Methoxyphenyl)telluro]ethyl}amine and Bis(2-aminoethyl) Telluride with o -Hydroxyacetophenone: Synthesis and Complexation Reactions with HgII, PdII and RuII , Crystal Structures of the Ligands, [Ru(p -cymene)Cl{H2NCH2CH2TeC6H4 -4-OCH3}]ClH2O and [RuCl{4-MeOC6H4TeCH2CH2NHCH(CH3)C6H4 -2-O,}]

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2004
Raghavendra Kumar P.
Abstract {2-[(4-Methoxyphenyl)telluro]ethyl}amine and bis(2-aminoethyl) telluride on treatment with o -hydroxyacetophenone gave the Schiff bases 4-MeOC6H4TeCH2CH2N=C(CH3)C6H4 -2-OH (L1) and 2-HOC6H4(CH3)C=NCH2CH2TeCH2CH2N=C(CH3)C6H4 -2-OH (L3), respectively. The reduction of L1 and L3 with NaBH4 resulted in 4-MeOC6H4TeCH2CH2NHCH(CH3)C6H4 -2-OH (L2) and 2-HOC6H4(CH3)CHNHCH2CH2TeCH2CH2NHCH(CH3)C6H4 -2-OH (L4), respectively, which have 1 or 2 chiral centers. The 1H and 13C NMR spectra of L1 to L4 were found to be characteristic. Treatment of L1 with [Ru(p -cymene)Cl2]2 resulted in [Ru(p -cymene)(4-MeOC6H4TeCH2CH2NH2)Cl]ClH2O (1) whereas in the reaction of L2 with [Ru(p -cymene)Cl2]2, the p -cymene ligand is lost resulting in [RuCl(L2 -H)] (4). The reactions of L1, L3 and L4 with HgBr2 resulted in complexes of the type [HgBr2(L)2] while Na2PdCl4 reacted with L1 to give [PdCl(L1 -H)]. The solid-state structures of L1, L3, 1 and 4 were determined by single-crystal X-ray diffraction studies. The very swift formation of the tellurated amine from a tellurated Schiff base (L1) by hydrolysis has been observed for the first time and has resulted in 1. The Ru,N and Ru,Te bond lengths in 1 are 2.142(3) and 2.6371 (4) , respectively. The replacement of the p -cymene ligand with a hybrid organotellurium ligand (L2 -H), resulting in 4, is also a first example of its kind. The Ru center in 4 has a square-planar geometry, with the Ru,N, Ru,Te, Ru,O and Ru,Cl bond lengths being 2.041(6), 2.4983(8), 2.058(5) and 2.308(2) , respectively. In the crystals of 4 there are secondary intermolecular TeCl interactions and intermolecular N,HO hydrogen bonds. This is the first example in which coordinated Te in a complex is engaged in two intermolecular secondary interactions. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


Crystal Structures of Conformationally Locked Cyclitols: An Analysis of Hydrogen-Bonded Architectures and their Implications in Crystal Engineering

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2007
Goverdhan Mehta
Abstract A qualitative study has been carried out on selected polycyclitols to evaluate the potential of conformational locking of hydroxy groups in lending predictability to the O,HO hydrogen-bonding network observed in the crystal structures of such compounds. The polycyclitols employed in this study are conformationally locked with all the hydroxy groups destined to be axial owing to the trans ring fusion(s) in the polycyclic carbon framework. The consequent formation of intramolecular O,HO hydrogen bonds between the 1,3- syn diaxial hydroxy groups now permits any packing pattern in the polycyclitols to be described in terms of a small group of intramolecularly bonded molecular motifs linked to their respective neighbors by four O,HO bonds. By using this model and the results of CSD analyses of polyols as a guide, the O,HO hydrogen-bonded packing motifs most likely to be observed in the crystal structure of each polycyclitol were proposed and compared with those obtained experimentally. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]


Interpenetrating 2D Manganese(II) Coordination Polymer Supported by 4,4,-Bis(dimethoxyphosphorylmethyl)-biphenyl Ligands

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2009
Xiangdong ZHANG
Abstract A novel coordination polymer [Mn(bdpbp)2(NO3)2]n (1), where bdpbp=4,4,-bis(dimethoxyphosphoryl- methyl)biphenyl, was prepared under mild condition. The structure has been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, luminescent property and thermogravimetric analyses. Structure of 1 exhibits infinite grid frameworks and forms two fold interpenetrating nets. Weak C,HO hydrogen bonds ensure the formation and stability of a three dimensional supramolecular network. [source]