Metal ionic size directed complexation in manganese(ii) coordination chemistry: efficient candidates showing phenoxazinone synthase mimicking activity

RSC Advances ◽  
2014 ◽  
Vol 4 (70) ◽  
pp. 37085-37094 ◽  
Author(s):  
Anangamohan Panja

Influence of the ionic size of metal on the diverse coordination chemistry of manganese(ii) has been examined by X-ray diffraction and IR spectral studies, and their relative phenoxazinone synthase activity has also been explored.

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 593
Author(s):  
Juan Miranda-Pizarro ◽  
Macarena G. Alférez ◽  
M. Dolores Fernández-Martínez ◽  
Eleuterio Álvarez ◽  
Celia Maya ◽  
...  

A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CH3C{(C6H4OR2)3], where R stands for Ph (1a), Xyl (1b, Xyl = 2,6-Me2-C6H3), iPr (1c), and Cy (1d). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors. As such, we report here the isolation and full characterization of a number of Au(I), Ag(I), Cu(I), Ir(III), Rh(III) and Ru(II) homotrimetallic complexes, including the structural characterization by X-ray diffraction studies of six of these compounds. We have observed that the flexibility of these trisphosphinites enables a variety of conformations for the different trimetallic species.


1989 ◽  
Vol 169 ◽  
Author(s):  
Winnie Wong‐Ng ◽  
Lawrence P. Cook ◽  
Michael D. Hill ◽  
Boris Paretzkin ◽  
E.R. Fuller

AbstractThe influence of the ionic size of the lanthanides R on melting relations of Ba2RCu3O6+x, where R=Y, Eu and Nd, was studied and compared with that of a high Tc superconductor mixed‐lanthanide phase Ba2(Y.75Eu.125Nd 125)Cu3O6+xThese materials have been characterized by a variety of methods including differential thermogravimetric analysis (DTA), scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy (EDX) and X‐ray powder diffraction. Single phase samples of Ba2(Y.75Eu.125Nd.125)Cu3O6+x were annealed at 1004, 1040, 1052, 1060, 1078, 1107 and 1160°C and quenched into a helium gas container cooled by liquid nitrogen. The SEM micrographs of these samples showed the progressive chnages in features of the microstructures from sintering and grain growth through melting and then recrystallization from the melt. The addition of the SEM technique in conjunction with X‐ray diffraction has been helpful in the study of phase equilibria in this system.


Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 982
Author(s):  
Devaraj Pandiarajan ◽  
Thomas Fox ◽  
Bernhard Spingler

The coordination chemistry of butane-2,3-dione bis (2′-pyridylhydrazone) towards the divalent first-row transition metals zinc and iron has been explored. Depending upon the conditions, the ligand in the six complexes was found to be either neutral, mono, or doubly deprotonated. The zinc(II) and iron(II) complexes were fully characterized by elemental analysis, mass spectrometry, and X-ray diffraction methods.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mareike C. Jahnke ◽  
F. Ekkehardt Hahn

Abstract The reactions of N-alkyl-N′-picolyl-benzimidazolium bromides or N,N′-dipicolyl-benzimidazolium bromide with silver oxide yielded the silver dicarbene complexes of the type [Ag(NHC)2][AgBr2] 1–4 (NHC = picoline-functionalized benzimidazolin-2-ylidene). The silver complexes 1–4 have been used in carbene transfer reactions to yield the gold(I) complexes of the type [AuCl(NHC)] 5–8 in good yields. A halide exchange at the metal center of complexes 5–8 with lithium bromide yielded the gold bromide complexes 9–12. Finally, the oxidation of the gold(I) centers in complexes 9–12 with elemental bromine gave the gold(III) complexes of the type [AuBr3(NHC)] 13–16. Molecular structures of selected Au(I) and Au(III) complexes have been determined by X-ray diffraction studies.


2004 ◽  
Vol 59 (11-12) ◽  
pp. 1372-1378 ◽  
Author(s):  
Peter J. Pogorzeleca ◽  
David H. Reid ◽  
Derek A. Tocher ◽  
James D. E. T. Wilton-Ely

The coordination chemistry of the unusual, pyrrole-stabilised thioaldehyde molecules, 3,5-dimethylpyrrole-2-carbothioaldehyde (HSPyMeHMe) and 3,5-dimethyl-4-ethylpyrrole-2-carbothioaldehyde (HSPyMeEtMe) has been investigated with nickel, palladium and platinum in the complexes [M(κ2- SPyMeRMe)2] (M = Ni, Pd, Pt; R = H, Et). The structure of the cyclometallated derivative [Pd(η2- C,N-C6H4CH2NMe2)(κ2-SPyMeEtMe)] was determined by X-ray diffraction.


1995 ◽  
Vol 50 (4) ◽  
pp. 642-648 ◽  
Author(s):  
Rolf W. Saalfrank ◽  
Klaus Schobert ◽  
Stefan Trümmer ◽  
Alexander Wolski

The new bistetrazole 13 has been obtained by subsequent formation of the two heterocyclic units. In methanolic solution 13 reacts with zinc(II) acetate to yield the pseudo-meso-1 D-coordination polymer [ZnL2(MeOH)]n (n = ∞) 14. The structure of 14 was established by single crystal X-ray diffraction. The generation of the polymeric chain 14 is understandable, if intermediate formation of coordinatively unsaturated zinc(II) buildingblocks (Δ)-15 and (Λ)-15 is assumed. Alternating linkage of the self-complementary chiral monomers 15, across one cyanofunction each, leads to 14 with zinc being essentially octahedrally coordinated. Compared with polymeric compounds of similar bridging ligands, the Zn ··· N≡C-distance in 14 (225,7 pm) is short.


1975 ◽  
Vol 13 (2) ◽  
pp. 65-70 ◽  
Author(s):  
H. C. Srivastava ◽  
A. K. Kulshreshtha ◽  
V. K. Srivastava

1989 ◽  
Vol 67 (2) ◽  
pp. 239-244 ◽  
Author(s):  
U. S. Rai ◽  
K. D. Mandal

The phase diagram of p-phenylenediamine – benzoic acid system, determined by the thaw–melt method, shows the formation of two eutectics and a 1:1 addition compound. The linear velocity of crystallization of pure components, eutectics and addition compound, determined by measuring the movement of growth front in a capillary, suggests that crystallization data obey the Hillig–Turnbull equation. Using experimental values of heats of fusion, entropy of fusion and excess thermodynamic functions were calculated and the results are explained on the basis of cluster formation in the melts. X-ray diffraction data infer that these eutectics are not simply the mechanical mixture of the two components and there is preferential ordering of atomic planes during their formation. The infrared spectral studies suggest the formation of intermolecular hydrogen bonding between the components forming the molecular complex. Keywords: organic eutectics, growth kinetics, phase diagram, thermochemistry, X-ray diffraction studies.


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