scholarly journals Crystal structure and redox potentials of the tppz-bridged {RuCl(bpy)}+ dimer

2018 ◽  
Vol 74 (9) ◽  
pp. 1250-1253
Author(s):  
Francisca N. Rein ◽  
Weizhong Chen ◽  
Brian L. Scott ◽  
Reginaldo C. Rocha

We report the structural and electrochemical characterization of the binuclear complex [μ-(C24H16N6){RuCl(C10H8N2)}2](PF6)2, which contains the bis-tridentate bridging ligand 2,3,5,6-tetrakis(pyridin-2-yl)pyrazine (tppz), the monodentate ligand Cl−, and the bidentate ligand 2,2′-bipyridine (bpy) {systematic name: μ-2,3,5,6-tetrakis(pyridin-2-yl)pyrazine-bis[(2,2′-bipyridine)chloridoruthenium(II)] bis(hexafluoridophosphate)}. The complete [(bpy)(Cl)Ru(tppz)Ru(Cl)(bpy)]2+ dication is generated by crystallographic twofold symmetry; the tppz bridging ligand has a significantly twisted conformation, with an average angle of 42.4° between the mean planes of adjacent pyridyl rings. The metal-coordinated chloride ligands are in a trans configuration relative to each other across the {Ru(tppz)Ru} unit. The RuII ion exhibits a distorted octahedral geometry due to the restricted bite angle [160.6 (3)°] of the tppz ligand. For bpy, the bond lengths of the Ru—N bonds are 2.053 (8) and 2.090 (8) Å, with the shorter bond being opposite to Ru—Cl. For the tridentate tppz, the Ru—N distances involving the outer N atoms trans to each other are 2.069 (8) and 2.072 (9) Å, whereas the Ru—N bond involving the central N atom has the much shorter length of 1.939 (7) Å as a result of the geometric constraints and stronger π-acceptor ability of the pyrazine-centered bridge. The Ru—Cl distance is 2.407 (3) Å and the intramolecular distance between Ru centers is 6.579 (4) Å. In the crystal, weak C—H...Cl and C—H...F interactions consolidate the packing.

2015 ◽  
Vol 71 (9) ◽  
pp. 1017-1021 ◽  
Author(s):  
Francisca N. Rein ◽  
Weizhong Chen ◽  
Brian L. Scott ◽  
Reginaldo C. Rocha

We report the structural characterization of [6′,6′′-bis(pyridin-2-yl)-2,2′:4′,4′′:2′′,2′′′-quaterpyridine](2,2′-bipyridine)chloridoruthenium(II) hexafluoridophosphate, [RuCl(C10H8N2)(C30H20N6)]PF6, which contains the bidentate ligand 2,2′-bipyridine (bpy) and the tridendate ligand 6′,6′′-bis(pyridin-2-yl)-2,2′:4′,4′′:2′′,2′′′-quaterpyridine (tpy–tpy). The [RuCl(bpy)(tpy–tpy)]+monocation has a distorted octahedral geometry at the central RuIIion due to the restricted bite angle [159.32 (16)°] of the tridendate ligand. The Ru-bound tpy and bpy moieties are nearly planar and essentially perpendicular to each other with a dihedral angle of 89.78 (11)° between the least-squares planes. The lengths of the two Ru—N bonds for bpy are 2.028 (4) and 2.075 (4) Å, with the shorter bond being opposite to Ru—Cl. For tpy–tpy, the mean Ru—N distance involving the outer N atomstransto each other is 2.053 (8) Å, whereas the length of the much shorter bond involving the central N atom is 1.936 (4) Å. The Ru—Cl distance is 2.3982 (16) Å. The free uncoordinated moiety of tpy–tpy adopts atrans,transconformation about the interannular C—C bonds, with adjacent pyridyl rings being only approximately coplanar. The crystal packing shows significant π–π stacking interactions based on tpy–tpy. The crystal structure reported here is the first for a tpy–tpy complex of ruthenium.


2017 ◽  
Vol 72 (1) ◽  
pp. 83-87 ◽  
Author(s):  
Gao-Feng Wang ◽  
Xiao Zhang ◽  
Zhao-Rong Liu ◽  
Yu-Chun Wang ◽  
Hong-Shi Jiang ◽  
...  

AbstractTwo complexes, {Mn(hfac)2(BIPMO)}n (1), {Cu(hfac)2(BIPMO)}n (2) [hfac=1,1,1,5,5,5-hexafluoro-pentane-2,4-dionato(–), BIPMO=bis(4-(1H-imidazol-1-yl)phenyl)methanone], with the V-shaped ligands were synthesized and characterized by infrared spectroscopy, elemental analyses, along with single-crystal X-ray diffraction analyses. The X-ray diffraction studies have shown that the metal ions in 1 and 2 are both six-coordinated to two nitrogen atoms of two BIPMO ligands and four oxygen atoms of two hfac ligands to form a distorted octahedral geometry. Each BIPMO ligand acts as a bridging ligand to link two adjacent metal(II) atoms to form a helical chain in the crystal structure.


2013 ◽  
Vol 69 (2) ◽  
pp. m79-m80 ◽  
Author(s):  
Weizhong Chen ◽  
Francisca N. Rein ◽  
Brian L. Scott ◽  
Reginaldo C. Rocha

The title heterolepticbis-terpyridine complex, [Ru(C15H11N3)(C17H11N3)](PF6)2·2CH3CN, crystallized from an acetonitrile solution as a salt containing two hexafluoridophosphate counter-ions and two acetonitrile solvent molecules. The RuIIatom has a distorted octahedral geometry due to the restricted bite angle [157.7 (3)°] of the twomer-arrangedN,N′,N′′-tridendate ligands,viz.2,2′:6′,2′′-terpyridine (tpy) and 4′-ethynyl-2,2′:6′,2′′-terpyridine (tpy′), which are essentially perpendicular to each other, with a dihedral angle of 87.75 (12)° between their terpyridyl planes. The rod-like acetylene group lies in the same plane as its adjacent terpyridyl moiety, with a maximum deviation of only 0.071 (11) Å from coplanarity with the pyridine rings. The mean Ru—N bond length involving the outer N atomstransto each other is 2.069 (6) Å at tpy and 2.070 (6) Å at tpy′. The Ru—N bond length involving the central N atom is 1.964 (6) Å at tpy and 1.967 (6) Å at tpy′. Two of the three counter anions were refined as half-occupied.


1992 ◽  
Vol 45 (11) ◽  
pp. 1933 ◽  
Author(s):  
PR Traill ◽  
AG Wedd ◽  
ERT Tiekink

The characterization of two MoVI complexes, cis -[MoO2(2-pymS)2] and cis -[MoO2(2-pyS)2] (where 2-pymSH is pyrimidine-2-thiol and 2-pySH is pyridine-2-thiol), and their reaction with Ph3P are reported. The X-ray structure of cis -[MoO2(2-pymS)2] shows the molybdenum atom to exist in a distorted octahedral geometry defined by two mutually cis oxygen atoms and two chelating 2-pymS ligands so that the two sulfur atoms occupy approximate trans positions. Crystals of cis -[MoO2(2-pymS)2] are monoclinic, space group P 21/n, with unit cell dimensions: a 9.301(3), b 12.121(2), c 11.303(3) �, β 112.62(3)�, V 1176.3 �3, Z 4. The structure was refined by a full-matrix least-squares procedure to R 0.067 for 1858 reflections with I ≥ 2.5 (I).


2014 ◽  
Vol 79 (8) ◽  
pp. 941-952
Author(s):  
Nikola Tasic ◽  
Jelena Rogan ◽  
Dejan Poleti ◽  
Lidija Radovanovic ◽  
Goran Brankovic

Four novel polymeric iron(III) complexes with 2,2?-bipyridine (bipy) and different aromatic polycarboxylato ligands as anions of phthalic (pht), isophthalic (ipht), terephthalic (tpht) and pyromellitic (pyr) acid were synthesized by ligand exchange reaction. The complexes were characterized by elemental and TG/DSC analysis, FTIR and diffuse reflectance UV-VIS-NIR spectroscopy and magnetic susceptibility measurements. Based on analytical and spectral data the formulae of the complexes are {[Fe4(bipy)2 (H2O)2(OH)6(pht)3]?2H2O}n (1), {[Fe4(bipy)2(Hipht)2(ipht)2(OH)6]?4H2O}n (2), {[Fe4(bipy)2(Htpht)2(OH)6(tpht)2]?4H2O}n (3) and {[Fe4(bipy)(H2O)8(OH)4 (pyr)2]?H2O}n (4). All complexes are red brown and low-spin with a distorted octahedral geometry and FeO6 or FeN2O4 chromophore. Polycarboxylato ligands have a bridging role in all cases, whereas monodentate COO groups are present in 2 and 3, bridging and chelate COO groups are established in 1 and 4. The thermal behaviour of 1-4 was investigated in detail and the molar dehydration enthalpies were calculated. According to the all those results, the structural formulae of the complexes 1-4 were proposed.


1984 ◽  
Vol 39 (6) ◽  
pp. 812-816 ◽  
Author(s):  
Y. M. Temerk ◽  
S. A. Ibrahim ◽  
M. M. Kamal

AbstractComplexes of arylidene salicyloyl- and benzoyl-hydrazones with the 3d metal ions, Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II), have been prepared using 2:1 ligand to metal ion ratio. Characterization of the isolated solids was accomplished by IR and electronic spectra, elemental analysis, and molar conductivity measurements. It is concluded that the two Schiff bases function as neutral bidentate ligands and the complexes formed assume a distorted octahedral geometry.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Huilu Wu ◽  
Fan Kou ◽  
Fei Jia ◽  
Bin Liu ◽  
Jingkun Yuan ◽  
...  

A new copper(II) complex with formulae of [Cu(buobb)2](pic)2, where buobb stands for the ligand of 1,3-bis(1- butylbenzimidazol-2-yl)-2-oxopropane and pic represents 2,4,6-trinitrophenol, has been synthesized and characterized by elemental analyses, molar conductivity, IR, UV-Vis spectra measurements, and cyclic voltammetry. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The coordination environment around each copper(II) atom can be described as a distorted octahedral geometry. The π-π stacking interactions link the copper(II) complex into a 1D infinite network. The interactions of the ligand and the copper(II) complex with calf thymus DNA (CT-DNA) are investigated by using electronic absorption titration, ethidium bromide-DNA displacement experiments, and viscosity measurements. Additionally, the copper(II) complex’s antioxidant properties have been investigated in vitro.


Author(s):  
Dohyun Moon ◽  
Jong-Ha Choi

The structure of the title double salt, [Cr(rac-chxn)3][ZnCl4]Cl·3H2O (chxn istrans-1,2-cyclohexanediamine; C6H14N2), has been determined from synchrotron data. The CrIIIion is coordinated by six N atoms of three chelating chxn ligands, displaying a slightly distorted octahedral coordination environment. The distorted tetrahedral [ZnCl4]2−anion, the isolated Cl−anion and three lattice water molecules remain outside the coordination sphere. The Cr—N(chxn) bond lengths are in a narrow range between 2.0737 (12) and 2.0928 (12) Å; the mean N—Cr—N bite angle is 82.1 (4)°. The crystal packing is stabilized by hydrogen-bonding interactions between the amino groups of the chxn ligands and the water molecules as donor groups, and O atoms of the water molecules, chloride anions and Cl atoms of the [ZnCl4]2−anions as acceptor groups, leading to the formation of a three-dimensional network. The [ZnCl4]2−anion is disordered over two sets of sites with an occupancy ratio of 0.94:0.06.


2016 ◽  
Vol 2 (4) ◽  
pp. 177
Author(s):  
Raj Kamal Rastogi ◽  
Sonu Sharma ◽  
Gulshan Rastogi ◽  
Alok K. Singh

The complexes of Benzil-2, 4-dinitrophenyl hydrazone-p- bromo aniline with Ti(III),V(III), VO(IV),MoO (V), Fe(II), Fe(III) have synthesized and characterized by elemental analysis, magnetic measurement data, molar conductance, TGA,UV-visible and IR spectra data. The complexes of Ti (III), V (III), Fe (II) and Fe (III) have octahedral geometry while VO (IV) and MoO(V) have distorted octahedral geometry due to the presence of M=O moiety.


2006 ◽  
Vol 62 (7) ◽  
pp. m1611-m1612 ◽  
Author(s):  
Hong-Ping Xiao

In the title compound, [Zn(C7H4O5S)(C13H14N2)(H2O)2]·C3H7NO, the ZnII atom is coordinated by two N atoms from two 1,3-di-4-pyridylpropane molecules, two O atoms from one 2-sulfonatobenzoate dianion and two aqua O atoms, in a distorted octahedral geometry. The 2-sulfonatobenzoate dianions function as chelating ligands and the 1,3-di-4-pyridylpropane as a μ2-bridging ligand, forming a chain. O—H...O hydrogen bonds link neighbouring chains into a three-dimensional network.


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