Synthesis and Structural Characterisation of Palladium(II) Complexes with N,N′,N-Tridentate N′-Substituted N,N-Di(2-picolyl)amines and their Application to Methyl Methacrylate Polymerisation

2014 ◽  
Vol 67 (6) ◽  
pp. 953 ◽  
Author(s):  
Sunghoon Kim ◽  
Dongil Kim ◽  
Yujin Song ◽  
Ha-Jin Lee ◽  
Hyosun Lee

The reaction of [Pd(CH3CN)2Cl2] with N′-substituted N,N-di(2-picolyl)amine-based ancillary ligands, for example N,N-di(2-picolyl)cyclohexylmethylamine (L1), N,N-di(2-picolyl)benzylamine (L2), N,N-di(2-picolyl)aniline (L3), and 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene (L4), in the presence of NaClO4 in ethanol yields a new series of [(NN′N)PdCl]X (X = ClO4, Cl) complexes, i.e. mononuclear [LnPdCl]ClO4 (Ln = L1, L2, L3) and binuclear [L4Pd2Cl2]Cl2. X-Ray crystallographic analysis determined that the Pd atom in complexes [(NN′N)PdCl]X showed a slightly distorted square-planar geometry involving three nitrogen atoms and a chlorido ligand. Moreover, the unit cell included a ClO4– or Cl– anion as the counterion. The complex [L1PdCl]ClO4 showed the highest catalytic activity for the polymerisation of methyl methacrylate in the presence of modified methylaluminoxane at 60°C among the mononuclear PdII complexes. Specifically, the activity of binuclear [L4Pd2Cl2]Cl2 was 2-fold higher than the corresponding mononuclear [L2PdCl]ClO4 per active palladium metal centre.

2010 ◽  
Vol 428-429 ◽  
pp. 140-143
Author(s):  
Chung Jung Chen ◽  
Chung K. Lai

A new type of 3,3'-(2-hydroxypropane-1,3-diyl) bis(azan-1-yl-1-ylidene)bis(2-(4-alkoxy phenyl)prop-1-en-1-ol) and their copper complexes were prepared and mesomorphic properties characterized. The mesomorphic properties of these copper complexes were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and powder X-ray diffraction. X-ray structural crystallographic analysis showed that these bimetallic compounds have two copper centers coordinated with central square planar geometry. These molecules all have total two 1a or five alkoxy sidechains 1b appended around the central core. The mesomorphic behavior exhibited was found to be dependent on the sidechain density. All compounds in 1a exhibited smectic mesophases, however, compounds in 1b exhibited hexagonal columnar phases (Colh), which were characterized by optical textures and confirmed by powder x-ray diffraction.


Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 607 ◽  
Author(s):  
Yin-Xia Sun ◽  
Ying-Qi Pan ◽  
Xin Xu ◽  
Yang Zhang

An unprecedented dinuclear CuII complex, [Cu2(L2)2], derived from a salamo-like chelating ligand H2L2, was produced by the cleavage of a newly synthesized, half-salamo-like ligand HL1 (2-[O-(1-ethyloxyamide)]oxime-3,5-dichloro-phenol). This was synthesized and characterized by elemental analyses, IR, UV–Vis and fluorescent spectra, single crystal X-ray diffraction analysis, and Hirshfeld surface analysis. X-ray crystallographic analysis indicated that the two CuII (Cu1 and Cu2) ions bore different (N2O3 and N2O2) coordination environments, the penta-coordinated Cu1 ion possessed a slightly twisted tetragonal pyramid geometry with the τ value τ = 0.004, and the tetra-coordinated Cu2 ion showed a slightly twisted square planar geometry. Interestingly, one oxime oxygen atom participated in the coordination reported previously. Moreover, an infinite two-dimensional layered supramolecular network was formed. Compared with HL1, the CuII complex possessed the characteristic of fluorescence quenching.


2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Takayoshi Fujii ◽  
Mihoko Kanno ◽  
Mitsuo Hirata

We have prepared the trinuclear complexes (3) and (4), from the reaction of with (1) and determined their structures by X-ray crystallographic analysis. In both complexes, two monoanions chelate the Cu(II) center in square-planar geometry, whereas the terminal Cu(II) center is four-coordinate and a distorted tetrahedron.


1996 ◽  
Vol 74 (11) ◽  
pp. 1990-1997 ◽  
Author(s):  
Robert A. Stockland Jr. ◽  
Gordon K. Anderson ◽  
Nigam P. Rath ◽  
Janet Braddock-Wilking ◽  
J. Christopher Ellegood

Treatment of [PdCl2(cod)] with tetrabenzyltin gives the benzylpalladium complex [PdCl(CH2Ph)(cod)] (cod = 1,5-cyclooctadiene), 1a, whose structure has been determined by X-ray crystallography. It adopts approximate square-planar geometry, with the double bonds perpendicular to the square plane. The corresponding ethylpalladium derivative 1b has been prepared by a similar method, but it is considerably less stable. It decomposes by (β-elimination to produce ethene and a transient hydride complex, which either undergoes migratory insertion to give [Pd2(μ-Cl)2(η1,η2-C8H13)2], 2a, or dinuclear reductive elimination with a second molecule of 1b to produce ethane, [PdCl2(cod)], free cyclooctadiene, and palladium metal. Complex 2a has also been prepared by reaction of [PdCl2(cod)] with NaBH4. At higher temperatures 2a converts to an equilibrium mixture with its η3-allyl isomer, 2b. Reactions of [PdCl2(cod)] or K2PdCl4 in the presence of cyclooctadiene in aqueous solution to produce 2a or 2b have also been investigated. Key words: palladium, diene complexes, allyl complexes, isomerization, β-elimination.


2019 ◽  
Vol 20 (3) ◽  
pp. 520 ◽  
Author(s):  
Giarita Ferraro ◽  
Tiziano Marzo ◽  
Maria Cucciolito ◽  
Francesco Ruffo ◽  
Luigi Messori ◽  
...  

Stable five-coordinate Pt(II) complexes have been highlighted as a promising and original platform for the development of new cytotoxic drugs. Their interaction with proteins has been scarcely studied. Here, the reactivity of the five-coordinate Pt(II) compound [Pt(I)(Me) (dmphen)(olefin)] (Me = methyl, dmphen = 2,9-dimethyl-1,10-phenanthroline, olefin = dimethylfumarate) with the model proteins hen egg white lysozyme (HEWL) and bovine pancreatic ribonuclease (RNase A) has been investigated by X-ray crystallography and electrospray ionization mass spectrometry. The X-ray structures of the adducts of RNase A and HEWL with [Pt(I)(Me)(dmphen)(olefin)] are not of very high quality, but overall data indicate that, upon reaction with RNase A, the compound coordinates the side chain of His105 upon releasing the iodide ligand, but retains the pentacoordination. On the contrary, upon reaction with HEWL, the trigonal bi-pyramidal Pt geometry is lost, the iodide and the olefin ligands are released, and the metal center coordinates the side chain of His15 probably adopting a nearly square-planar geometry. This work underlines the importance of the combined use of crystallographic and mass spectrometry techniques to characterize, in detail, the protein–metallodrug recognition process. Our findings also suggest that five-coordinate Pt(II) complexes can act either retaining their uncommon structure or functioning as prodrugs, i.e., releasing square-planar platinum complexes as bioactive species.


Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 476 ◽  
Author(s):  
Xuan-Dien Luong ◽  
Xuan-Truong Nguyen

A [O,N] bidentate π-expanded ligand system, (E)-1-(n-octylimino)methylpyren-2-ol (2), was newly synthesized via a six-step synthesis from pyrene. The ligand 2 reacts with [PtCl2(PhCN)2] in chlorobenzene and the presence of a base at reflux for 2 h under the formation of (2(Pt)) complex with a yield of 70%. The molecular structure of (2(Pt)), studied by common spectroscopic methods and X-ray diffraction, shows a square planar geometry with a trans-configuration of the ligands. The molecular structure, absorption spectra, electrochemical properties, and phosphorescence characteristics of the (2(Pt)) complex are discussed, emphasizing the comparison with those of the previously reported Pt complex (1(Pt)) containing the isomeric ligands of 2, (E)-2-(n-octylimino)methylpyren-1-ol. The DFT calculations of the two Pt complexes are carried out and exhibit a clear explanation of the relationship between their physico-chemical characteristics.


2006 ◽  
Vol 62 (5) ◽  
pp. m974-m976 ◽  
Author(s):  
Gideon Steyl

The title compound, [Pd(C7H5O2)Cl(C18H15P)], is a new type of α-diketone palladium(II) complex containing a tertiary arylphosphine. It crystallizes with a distorted square-planar geometry about the palladium(II) metal centre. The most important bond distances and angles include Pd—O (trans P) = 2.0481 (12) Å, Pd—O (trans Cl) = 2.0016 (12) Å, Pd—P = 2.2268 (4) Å, Pd—Cl = 2.2770 (5) Å, O—Pd—O = 80.22 (5)° and O—C—C—O = 3.7 (2)°. A π–π stacking interaction is observed between neighbouring tropolonate groups, with an interplanar distance of 3.377 (6) Å.


1986 ◽  
Vol 39 (7) ◽  
pp. 1101 ◽  
Author(s):  
GA Lawrance ◽  
BW Skelton ◽  
AH White ◽  
P Comba

Reduction of [2-methyl-2-nitro-N,N?-bis(pyridin-2-ylmethyl)propane- 1,3-diamine]copper(II) with zinc in aqueous hydrochloric acid and subsequent recomplexation yields the macromonocyclic complex (6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)copper(II) perchlorate as the major product, apparently by cleavage of both pyridine rings from the precursor ligand and direct recombination of two saturated residues. Catalytic reduction of the nitro group in the precursor compound can be achieved cleanly over palladium-carbon with hydrogen. The macrocyclic complex crystallized in the space group P21/c, a 8.031(4), b 17.45(1), c 8.436(5) Ǻ, β 117.87(4)°, Z 2; for a single-crystal X-ray structure determination R was 0.078 for 1378 'observed' reflections. The complex is centrosymmetric, the macrocycle having pendant amines on opposite sides of the macrocyclic plane, while perchlorate oxygen atoms occupy the axial sites with Cu-O at 2.59 Ǻ. Observed Cu-N distances of 2.022(6) and 1.996(7) Ǻ are longer than usual for copper(II) amines. Electron spin resonance and electronic spectroscopy define an essentially square-planar geometry in solution, with only weak axial interactions.


2015 ◽  
Vol 70 (10) ◽  
pp. 711-718
Author(s):  
An-Qi Dai ◽  
Qi Yan ◽  
Jing Zhong ◽  
Sheng-Chun Chen ◽  
Ming-Yang He ◽  
...  

AbstractReaction of 3,4,5,6-tetrachloro-1,2-benzenedicarboxylyic acid (1,2-H2BDC-Cl4) with transitional metal salts at room temperature in mixed DMF/H2O solvent affords three complexes formulated as [Cu(1,2-HBDC-Cl4)2(DMF)2] (1), {[Cd(1,2-HBDC-Cl4)2(H2O)4]·2DMF} (2), and {[Ni(1,2-BDC-Cl4)(H2O)5]·DMF·H2O} (3) (DMF = N,N-dimethylformamide). All these complexes have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray crystallography. In 1, the CuII ion is four-coordinated with a square-planar geometry formed by two 1,2-HBDC-Cl4 anions and two DMF ligands; in 2, the CdII ion takes an octahedral geometry coordinated by two 1,2-HBDC-Cl4 anions and four aqua ligands; while in 3, the NiII ion is octahedrally coordinated by one 1,2-BDC-Cl4 dianion and five aqua ligands. Intermolecular O–H···O hydrogen bonds and Cl···Cl (or C–H···Cl) interactions provide a significant contribution to stabilizing the three mononuclear structures in the solid state. The results suggest that structural differences among them are attributed to the influence of transition metal ions. The fluorescence of the complexes and of 1,2-H2BDC-Cl4 has been investigated. No significant metal effect has been observed.


IUCrData ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Yansi Zhao ◽  
Yanmei Chen

In the title complex, [Cu(C7H7N2O2)2]·2CH3OH, the metal centre is coordinated by two 4-aminophenylhydroxamate bidentate ligands, in a distorted square-planar geometry. The asymmetric unit is completed by two methanol solvent molecules, which are involved in hydrogen bonding with N—H functionalities of the free hydroxamate groups. The crystal structure also features N—H...O bonds formed by the NH2 groups, and O—H...O hydrogen bonds with the methanol solvent molecules as donors.


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