Complexes of the tripodal nitrilotrimethylenetrisphosphonic (H6L) and P,P′,P″-triphenylnitrilotrimethylenetrisphosphinic (H3L°) acids with the copper(II) ion. Synthesis and characterization of [Hpy][Cu(H3L)(H2O)] and [Cu(HL°)(py)]2·2Me2CO (original) (raw)
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Polyhedron, 1998
The stoichiometries and stability constants of the copper"II# complexes with seven amino! diphosphonates ðRÐN"CH 1 PO 2 H 1 # 1 \ LŁ containing iminomethylenephosphonate moieties have been deter! mined pH!metrically at 14>C and at an ionic strength of 9[19 mol dm −2 "KCl#[ The results suggest for L 0Ð5 only equimolar species] ðCu"H 1 L#\ ðCu"HL#\ ðCuLŁ and two hydroxo ðCuH −0 LŁ and ðCuH −1 LŁ\ in the pH range of 1Ð00[4\ the only di}erence is the presence of an additional ðCu"H 2 L#Ł species "½04)# at low pH for N!2! picolyliminodi"methylenephosphonic# acid[ For L 6 the model contains protonated and non!protonated 0]1 species[ From the comparative analysis of the stability and the spectroscopic "UVÐVIS and EPR# data it has been established that the ligands in ðCuHLŁ and ðCuLŁ are tridentate^the formation of two _ve!membered chelate rings leads to very stable complexes[ The LMCT bands from O − "PO 2 1− # and N imino to Cu 1¦ are at 114Ð 120 and 291Ð166 nm[ Þ 0887 Elsevier Science Ltd[ All rights reserved
Polyhedron, 2011
The complex formation between copper(II) and (pyridinyl)aminomethane-1,1-diphosphonic acid derivatives was studied by means of pH-potentiometry, spectroscopic methods (UV-Vis, EPR) and mass spectrometry (MS). The bisphosphonate ligands form polynuclear Cu 3 H x L 3 (x = 4 ,3, 2, 1, 0, À1) species besides the mononuclear 1:1 and 1:2 metal-to-ligand molar ratio complexes. Two phosphonate groups are basic binding sites for the metal ion. It is suggested that in the polynuclear complexes the ligands adopt chelating and bridging modes via the four oxygen atoms of the two phosphonate groups.
Inorganica Chimica Acta, 2020
The chemical preparation, crystal structure and spectroscopic characterization of two new Cu(II) complexes [Cu(ampymo)4](O2CMe)2, ( 1 ) and [Cu(C5H7N3O)2(H2O)3](CH3COO)2, [Cu(ampymo)2(H2O)3](O2CMe)2, ( 2 ) with the monodentate ligand 2-amino-6-methylpyrimidin-4-(1H)-one, (ampymo), are reported. In ( 1 ), the Cu(II) atom is four-coordinated, in a square planar fashion, by nitrogen atoms of four ampymo ligands. In ( 2 ), it is five-coordinated in a square pyramidal fashion by two pyrimidine nitrogen atoms and three water oxygen atoms. The crystal structure of ( 1 ) is stabilized by N H⋯O hydrogen bonds with pillars of the cationic complexes alternating with channels occupied by the acetate anions. In the atomic arrangement of ( 2 ), the complex cations are located parallel to the (a, b) plane between which the acetate anions intercalate by establishing hydrogen bonds with these cations to form a tridimensional network. The vibrational absorption bands were identified by infrared spect...
Mixed-Ligand Complexes of Copper(II) with α-Hydroxycarboxylic Acids and 1,10-Phenanthroline
Zeitschrift für anorganische und allgemeine Chemie, 2001
Eight new two-ligand complexes of copper(II) with 1,10-phenanthroline and one of four different a-hydroxycarboxylic acids (glycolic, lactic, mandelic and benzylic) were prepared. The complexes of general formula [Cu(HL) 2 -(phen)]´nH 2 O (HL = monodeprotonated acid) (1±4) were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermo-gravimetric analysis. The complexes of general formulae [Cu(HL)(phen) 2 ](HL)´H 2 L´nSolv [1 a (HL = HGLYO ± , n = 1, Solv = MeCN) and 3 a (HL = HMANO ± , n = 0)] and [Cu(L)(phen)(OH 2 )]´nH 2 O [2 a (L = LACO 2± , n = 4) and 4 a (L = BENO 2± , n = 2)] were characterized by X-ray diffractometry. In all these latter a pentacoordinated copper atom has a basically square pyramidal coordination polyhedron, the distortion of which towards a trigonal bipyramidal configuration has been evaluated in terms of the parameter s. In 1 a and 3 a there are three forms of a-hydroxycarboxylic acid: a monodentate monoanion, a monoanionic counterion, and a neutral molecule lying in the outer coordination sphere; in 2 a and 4 a the a-hydroxycarboxylic acid is a bidentate dianion coordinating through carboxyl and hydroxyl oxygens. Parameter s definiert. In 1 a und 3 a liegen die a-Hydroxycarbonsa È ure in drei Formen vor: als einza È hniges Monoanion, als monoanionisches Gegenion und als neutrales Moleku È l in der a È uûeren Koordinationsspha È re; in 2 a und 4 a ist die a-Hydroxycarbonlsa È ure ein zweiza È hniges Dianion, das u È ber die Carboxyl-und Hydroxyl-Sauerstoffatome koordiniert.
Journal of Chemical Sciences, 2015
Equimolar reaction of copper(I) bromide with 2-thiouracil (tucH 2) in acetonitrile-methanol formed a light yellow solid which on subsequent treatment with a mole of triphenyl phosphine (PPh 3) in chloroform has yielded a sulfur-bridged dinuclear complex, [Cu 2 Br 2 (µ-S-tucH 2) 2 (PPh 3) 2 ]•2CHCl 3 1. A reaction of copper(I) bromide with two moles of 2,4-dithiouracil (dtucH 2) in acetonitrile-methanol followed by addition of two moles of PPh 3 , designed to form [Cu(µ-S,S-dtuc) 2 (PPh 3) 4 Cu] 2a, instead resulted in the formation of previously reported polymer, {CuBr(µ-S,S-dtucH 2)(PPh 3)} n 2. Reaction of copper(I) iodide with 2thiouracil (tucH 2) and PPh 3 in 1:1:2 molar ratio (Cu:H 2 tuc:PPh 3) as well as that of copper(I) thiocyanate with pyridine-2-thione (pySH) or pyrimidine-2-thione (pymSH) and PPh 3 in similar ratio, yielded an iodo-bridged unsymmetrical dimer, [(PPh 3) 2 (µ-I) 2 Cu(PPh 3)] 3 and thiocyanate bridged symmetrical dimer, [(PPh 3) 2 Cu(µ-N,S-SCN) 2 Cu(PPh 3) 2 ] 4, respectively. In both the latter reactions, thio-ligands which initially bind to Cu metal center, are de-ligated by PPh 3 ligand.
Polyhedron, 2002
Stabilities of the mixed-ligand complexes of Cu 2 + ion with N, N,N%,N¦,N¦-pentamethyldiethylenetriamine [N,N,N%,N¦,N¦-pentamethyl-{bis(2-aminoethyl)amine}, Me 5 dien] as a primary ligand and a-alaninehydroxamic acid [2-amino-N-hydroxypropanamid, a-Alaha] or b-alaninehydroxamic acid [3-amino-N-hydroxypropanamid, b-Alaha] as a secondary ligand L and their absorption and EPR spectra at various pH values are reported. The visible spectra exhibit a characteristic red shift and a shoulder at lower energies indicating a five-coordinate structure of the formed complexes. The change of the EPR spectral parameters as a function of pH reflects two modes of an equatorial-axial chelation by the aminohydroxamic acid ligand L in the [Cu(Me 5 dien)(HL)] 2 + and [Cu(Me 5 dien)(L)] + species.
Inorganic Chemistry, 1996
The tripodal tetramine ligands N(CH 2 CH 2 CH 2 NH 2) 3 (trpn) and N[(CH 2 CH 2 CH 2 NH 2) 2 (CH 2 CH 2 NH 2)] (332) react with Cu(NO 3) 2 ‚3H 2 O in water to give light blue copper(II) complexes. These were characterized by X-ray crystallography to be the square-pyramidal binuclear Cu(II) species [Cu(trpn)(NO 3)] 2 (NO 3) 2 and [Cu(332)(NO 3)] 2-(NO 3) 2 ‚2H 2 O. Selected crystallographic details are as follows, respectively: formula C 18 H 48 Cu 2 N 12 O 12 , C 16 H 48-Cu 2 N 12 O 14 ; M) 751.74, 759.72 Da; both triclinic; both P1 h; a) 8.4346(8), 8.446(4) Å; b) 9.0785(9), 8.744(3) Å; c) 11.9310(12), 12.007(3) Å; R) 94.50(1), 102.68(2)°;) 103.56(1), 94.79(3)°; γ) 117.42(1), 117.69-(4)°; V) 769.7(5), 748.2(13) Å 3 ; both Z) 1; R) 4.16, 4.00; R w) 11.34, 6.74 for 2887 (I g 2σ(I)), 2457 (F o 2 g 3σ(F o 2)) structure factors and 199, 209 refined parameters. The binuclear complex dications exhibit a squarepyramidal coordination geometry around the copper atoms. Three amine functions (one tertiary and two primary) are coordinated to one copper atom and the remaining primary amine arm bridges to the second copper center. Potentiometric and visible spectrophotometric studies show that a protonated square-pyramidal [Cu(HL)(H 2 O) 2 ] 3+ cation (L) trpn, 332, 322 (322) N[(CH 2 CH 2 CH 2 NH 2)(CH 2 CH 2 NH 2) 2 ])) predominates in the intermediate pH region, in contrast to the established trigonal-bipyramidal structure of the tren (tren) tris(2-aminoethyl)amine)) complex of Cu(II). Each [Cu(HL)(H 2 O) 2 ] 3+ has one protonated uncoordinated ligand arm which explains the formation of the binuclear species at neutral pH.