A convenient and selective route to a trans-difunctionalized macrocyclic hexadentate N4O2 ligand

2001 ◽  
Vol 79 (7) ◽  
pp. 1105-1109 ◽  
Author(s):  
Hongyan Luo ◽  
Robin D Rogers ◽  
Martin W Brechbiel

The synthesis and characterization of a novel difunctionalized tetraaza macrocycle, 1,8-bis(2-hydroxybenzyl)-1,4,8,11-tetraazacyclotetradecane (abbreviated H2bcyclamb), is described. The diprotic hexadentate ligand N4O2 was conveniently synthesized in two steps by the cyclic condensation reaction of 1,4,8,11-tetraazacyclotetradecane (abbreviated cyclam) and salicylaldehyde, followed by NaBH4 reduction of the cyclic hexahydropyrimidine condensate. The difunctionalization was selective and is the first procedure of trans-difunctionalization of a tetraazamacrocycle, without generating mono-, tri-, or tetra-functionalized products, with only 1,8-difunctionalized product being isolated, and with the convenience of the functionalization occurring as a result of deprotection. The trans-arrangement of the two functional groups in H2bcyclamb was verified by X-ray crystallographic studies of the copper(II) complex [Cu(H2bcyclamb)](OAc)2·2H2O. The crystal is monoclinic, P21/c, with a = 10.0931(2), b = 13.8820(1), c = 10.8752(1) Å, β = 106.332(1)°, V = 1462.26(3) Å3. The structure of [Cu(H2bcyclamb)](OAc)2·2H2O also shows the metal ion in an elongated octahedral geometry.Key words: 1,8-difunctionalized, cyclam, copper(II) complex.

2009 ◽  
Vol 13 (02) ◽  
pp. 223-234 ◽  
Author(s):  
Tomasz Goslinski ◽  
Ewa Tykarska ◽  
Wojciech Szczolko ◽  
Tomasz Osmalek ◽  
Aleksandra Smigielska ◽  
...  

The condensation reaction of 2-amino-3-[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile with a series of diketones led to novel dinitriles, of which 2-(2,5-dimethyl-1H-pyrrol-1-yl)-3-[methyl(3-pyridylmethylene)amino]-2(Z)-butene-1,4-dinitrile, the product of the Paal-Knorr reaction, was successfully utilized in the Linstead macrocyclization towards symmetrical and unsymmetrical porphyrazines. NMR and X-ray study revealed an almost perpendicular orientation of the pyrrolyl groups in relation to the porphyrazine platform. The newly synthesized macrocycles with different peripheral groups show interesting spectroscopic and electrochemical properties. Due to selective sensor/coordination properties they are expected to find applications as chemical sensors and electronic materials.


1992 ◽  
Vol 47 (6) ◽  
pp. 829-836 ◽  
Author(s):  
Henry Strasdeit

The isolation of 3,6,9,12-tetraazatetradecane-1,14-diamine (linear isomer of pentaethylenehexamine, linpen) from a technical polyamine mixture is described. In methanol, linpen acts as a hexadentate ligand towards cadmium(II). The solid compounds [Cd(linpen)](BPh4)2 (1), [Cd(linpen)](BPh4)2•2 DMSO (2) and [Cd(linpen)](BF4)2 (3) have been isolated and characterized by elemental analysis, spectroscopy and X-ray powder diffraction. The 113Cd NMR resonance of 1 is at 351 ppm (0.30 M in DMSO-d6, standard: 0.10 M Cd(ClO4)2 in D2O).2 and 3 have been structurally characterized by single-crystal X-ray diffraction. 2: C 2/c; a = 19.337(1)Å, b = 17.937(1)Å, c = 18.584(1)Å, β = 111.54(1)°; Z = 4, R = 0.034, Rw = 0.033.3: P21/n; a = 8.607(1)Å, b = 14.851(2)Å, c = 15.703(2)Å, ß = 91.21(2)°; Z = 4,R = 0.083, Rw = 0.072. Both compounds contain discrete [Cd(linpen)]2+ complexes. The hexamine wraps around the metal ion in a helical manner. This results in a strong distortion of the coordination polyhedron. The mean Cd-N bond lengths are 2.38Å and 2.37Å for 2 and 3, respectively.Models for MN6 centers in metal-polyethyleneimine (PEI) complexes are derived from the structure of [Cd(linpen)]2+. For example, loops at the MN6 site in molecules of linear PEI are proposed.


2021 ◽  
Vol 33 (9) ◽  
pp. 2157-2161
Author(s):  
F.M. Nareetsile ◽  
R. Gontse ◽  
O.A. Oyetunji ◽  
V.C. Obuseng

Hexadentate ligand of the type N,N,N′,N′-tetrakis(2-pyridylmethyl)alkanediamine (where alkane is butane (L1), hexane (L2) and octane (L3) reacted with Ni(ClO4)2·6H2O (stoichiometry 1:1) in alcoholic solutions yielding mononuclear complexes of the type [Ni(L)](ClO4)2·xH2O. The ligand L1 reacted with Ni(ClO4)2·6H2O in ethanol medium to give a violet powder of [Ni(L1)](ClO4)2·3H2O. The other mononuclear nickel(II) complexes using L2 and L3 were synthesized in methanol solution to give violet powders of [Ni(L2)](ClO4)2·2H2O and [Ni(L3)](ClO4)2·2H2O, respectively. All the three complexes were characterized by IR and elemental analysis. The X-ray crystallographic results for the purple crystals of [Ni(L1)](ClO4)2·3H2O shows the octahedral geometry on the Ni(II) ions together with the tetrahedral perchlorate anions separated from the [Ni(L1)]2+ cation. The crystal structure data show monoclinic space group P 21/c; a = 17.1748(10), b = 9.8273(6), c = 17.8146(10) Å; α = 90º, β = 95.0200(10)º, γ = 90º; V = 2995.2(3) Å3 , Z = 4.


2015 ◽  
Vol 2 (2) ◽  
pp. 16-22
Author(s):  
Manimekalai R ◽  
Kalpanadevi K ◽  
Anjutha Prabha N ◽  
Raina O

Metal cinnamate monohydrazinates of the formula M(cin)2N2H4, where M= Co or Zn, nickel crotante monohydrazinate monohydrate Ni(crot)2N2H4.H2O, metal cinnamate and crotonate dihydrazinates M(cin)2(N2H4)2 Where M = Co, Ni, Zn or Cd , M(crot)2(N2H4)2 Where M = Co or Ni and cadmium crotante dihydrazinate monohydrate Cd(crot)2(N2H4)2.H2O have been prepared and characterized by spectral, thermal and X-ray diffraction studies. Electronic spectra indicate that the cobalt and nickel complexes are high-spin octahedral complexes. The IR data show that the binding of hydrazine and the unsaturated carboxylate anion to the metal ion is bidentate. TG-DTA studies show that metal complexes undergo decomposition through metal carboxylate intermediate to give respective metal oxide as the final product. Xray powder diffraction patterns of the complexes indicate isomorphism among them.


2018 ◽  
Vol 2 (1) ◽  
pp. 7
Author(s):  
S Chirino ◽  
Jaime Diaz ◽  
N Monteblanco ◽  
E Valderrama

The synthesis and characterization of Ti and TiN thin films of different thicknesses was carried out on a martensitic stainless steel AISI 410 substrate used for tool manufacturing. The mechanical parameters between the interacting surfaces such as thickness, adhesion and hardness were measured. By means of the scanning electron microscope (SEM) the superficial morphology of the Ti/TiN interface was observed, finding that the growth was of columnar grains and by means of EDAX the existence of titanium was verified.  Using X-ray diffraction (XRD) it was possible to observe the presence of residual stresses (~ -3.1 GPa) due to the different crystalline phases in the coating. Under X-ray photoemission spectroscopy (XPS) it was possible to observe the molecular chemical composition of the coating surface, being Ti-N, Ti-N-O and Ti-O the predominant ones.


2020 ◽  
Vol 10 ◽  
pp. 184798042096688
Author(s):  
Galo Cárdenas-Triviño ◽  
Sergio Triviño-Matus

Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.


Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 721 ◽  
Author(s):  
Jorge A. Ramírez-Gómez ◽  
Javier Illescas ◽  
María del Carmen Díaz-Nava ◽  
Claudia Muro-Urista ◽  
Sonia Martínez-Gallegos ◽  
...  

Atrazine (ATZ) is an herbicide which is applied to the soil, and its mechanism of action involves the inhibition of photosynthesis. One of its main functions is to control the appearance of weeds in crops, primarily in corn, sorghum, sugar cane, and wheat; however, it is very toxic for numerous species, including humans. Therefore, this work deals with the adsorption of ATZ from aqueous solutions using nanocomposite materials, synthesized with two different types of organo-modified clays. Those were obtained by the free radical polymerization of 4-vinylpyridine (4VP) and acrylamide (AAm) in different stoichiometric ratios, using tetrabutylphosphonium persulfate (TBPPS) as a radical initiator and N,N′-methylenebisacrylamide (BIS) as cross-linking agent. The structural, morphological, and textural characteristics of clays, copolymers, and nanocomposites were determined through different analytical and instrumental techniques, i.e., X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). Adsorption kinetics experiments of ATZ were determined with the modified and synthesized materials, and the effect of the ratio between 4VP and AAm moieties on the removal capacities of the obtained nanocomposites was evaluated. Finally, from these sets of experiments, it was demonstrated that the synthesized nanocomposites with higher molar fractions of 4VP obtained the highest removal percentages of ATZ.


2020 ◽  
Vol 75 (6-7) ◽  
pp. 597-603
Author(s):  
Birgit Fuchs ◽  
Hubert Huppertz

AbstractThe non-centrosymmetric scandium borate ScB6O9(OH)3 was obtained through a high-pressure/high-temperature experiment at 6 GPa and 1473 K. Single-crystal X-ray diffraction revealed that the structure is isotypic to InB6O9(OH)3 containing borate triple layers separated by scandium layers. The compound crystallizes in the space group Fdd2 with the lattice parameters a = 38.935(4), b = 4.4136(4), and c = 7.6342(6) Å. Powder X-ray diffraction and vibrational spectroscopy were used to further characterize the compound and verify the proposed structure solution.


Sign in / Sign up

Export Citation Format

Share Document