Spyros P. Perlepes

Coordinating properties of isoorotic acid

Abstract The complexes [M(H 2 isor) 2 (H 2 O) 2 ]·H 2 O (M = Mn, Co, Ni, Cu, Zn), [M(H 2 isor) 2 (H 2 O) 2 ] (M = Fe, Cd), and [M(Hisor)(H 2 O) 2 ] (M = Hg,Pd), where H 3 isor = isoorotic acid, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, x-ray powder patterns, thermal methods, magnetic susceptibilities, and spectral (IR and far-IR, Raman, ligand field) studies. Pseudo-octahedral monomeric stereochemistries are assigned for the Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) complexes in the solid state, while [Pd(Hisor)(H 2 O) 2 ] has a square planar structure. The H 2 isor − ion behaves as a bidentate chelated O carboxylato , O(4) ligand; the uncoordinated amide group of H 2 isor − is present in the lactim (enolic) tautomeric form in the Cu(II) and Cd(II) complexes. Only Pd(II) and Hg(II) promote deprotonation of the monolactim form on coordination and yield 1:1 neutral complexes of the doubly deprotonated ligand; the Hisor 2− ion behaves as a bidentate chelated O carboxylato , O(4) deprotonated enolic ligand.

The coordination chemistry of N-(2-pyridyl)pyridine-2′-carboxamide; A potentially tridentate ligand containing one secondary amide and two 2-pyridyl donor groups

Abstract New complexes of the general compositions M(LH)X 2 (M = Co, Zn; X = Cl, Br, I), Zn(LH)(NCS) 2 , Zn(LH)(NO 3 ) 2 ·H 2 O, Cu(LH)X 2 (X = Cl, Br, ONO 2 ), Ni(LH)Cl 2 ·H 2 O, Co(LH) 2 X 2 (X = NCS, ONO 2 ), Ni(LH) 2 X 2 (X = Cl, Br, NCS, ONO 2 ), Pt(LH) 2 Cl 2 and MLCl· n H 2 O (M = Ni, Cu, Pd; n = 2, 3), where LH = N -(2-pyridyl)pyridine-2′-carboxamide, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, X-ray powder patterns, thermal methods, magnetic susceptibilities and spectroscopic (IR, ligand field, 1 H NMR) studies. Pseudotetrahedral, square planar, square pyramidal and distorted octahedral stereochemistries are tentatively assigned in the solid state. Most complexes appear to be monomeric, while polymeric structural types are attributed for Ni(LH)Cl 2 ·H 2 O and CuLCl·2H 2 O. The neutral amide group of LH is coordinated to Co(II), Ni(II), Cu(II) and Zn(II) through oxygen, while N-coordination is observed for PdLCl·2H 2 O. The amide group of L − is bound to different Cu(II) atoms in CuLCl·2H 2 O through both its nitrogen and oxygen. The rare O-coordination of the deprotonated amide bound is proposed for NiLCl· 3H 2 O. The N(1) atom is not involved in coordination except in the complexes Ni(LH)Cl 2 ·H 2 O, NiLCl· 3H 2 O and CuLCl·2H 2 O, where both pyridine residues are coordinated. The variation in structural types observed is believed to be a consequence of the stereochemical adaptability of the ligand to the electronic demands of the metal ions.

Metal complexes containing the monoanion, dianion and the neutral form of the ligand N-(2-carboxylphenyl)pyridine-2′-carboxamide

New complexes of the formulae M(LH)2·nH2O (M = Co, Ni, Cu, Zn; n = 2, 2.5, 3), Cu2(LH)2L· 3H2O, PdL·H2O, Pt3(LH)4L·7H2O, M2(LH)2(OH)2· nH2O (M = Co, Ni, Zn; n = 2, 4), CuL, M(LH2)2Cl2· EtOH (M = Co, Cu; EtOH = ethanol), Ni(LH2)2Cl2· EtOH·H2O, M(LH2)2X2 (M = Co, Ni; X = NCS, ONO2), Zn(LH2)2(NO3)2, Zn(LH2)(LH)Cl, Cu(LH2)- (LH)NO3 and Cu3(LH)3L(NO3), where LH2=N-(2- carboxylphenyl)pyridine-2′-carboxamide, have been isolated. The complexes were characterised by elemental analyses, conductivity measurements, magnetic moments and spectral (IR, 1H NMR and electronic) studies. Varying stereochemistry is assigned for the complexes prepared in the solid state. The complexes M(LH)2·nH2O (M = Co, Ni, Cu, Zn), Cu2- (LH)2L·3H2O and Cu3(LH)3L(NO3) appear to be polymeric, while dimeric structural types are assigned for M2(LH)2(OH)2·nH2O (M = Co, Ni, Zn) and CuL. Only palladium(II) at acidic pH and copper(II) at basic pH promote amide deprotonation on coordination and yield doubly deprotonated complexes. Coordination of the neutral carboxylic group is not observed for the complexes of LH2; the carboxylate ion exhibits monodentate coordination in the compounds of LH- and L2-. The neutral amide group of the ligands LH2 and LH− is coordinated to the metal ions through oxygen, while N(amide)-coordination is observed for the L2- complexes. The secondary amide bond shows the rare iminol type of coordination in Cu(LH)2·2H2O.

PSEUDOTETRAHEDRAL COBALT(II) COMPLEXES OF C3v and Cs SYMMETRIES

Abstract New complexes of the general types HCoX3 ·nL and HCo Y2X·nL (X=Br, I; Y=Cl, Br, I; L=diethyl ether, pyridine, aniline; n=1, 2, 3 and 4) have been prepared and characterized by elemental analyses, molar conductance measurements, magnetic measurements, spectral (UV, visible, IR and far-IR) data and X-ray powder patterns. All the magnetic and spectroscopic results indicate that pseudotetrahedral [CoX3L]− and [CoY2XL]− anions are present in the solid pyridine and aniline complexes. The data for the solid compounds are compatible with, and lend support to, outer spheres comprising (N[sbnd]H[sbnd]N)+ groups.

Use of ethyl oxamate for syntheses of oxamato(-1) and novel μ-oxamato(-2) complexes

SummaryThe use of ethyl oxamate for the synthesis of inorganic oxamato complexes is reported. A reaction system leading to the preparation of the novel polymeric μ-oxamato(-2) complexes [M(oxm)(H2O)2]x (M=Cu, Zn, Cd), [Co(oxm)(H2O)2]x·0.5xH2O and [Ni(oxm)(H2O)2]x·xH2O is described (H2oxm = oxamic acid). Ethyl oxamate can also be used for the preparation of monomeric oxamato(-1) complexes.ZusammenfassungEs wird der Einsatz von Ethyloxamat für die Synthese von anorganischen Oxamato-Komplexen beschrieben. Ein Reaktions-System für die Herstellung von neuen μ-Oxamato(-2)-Komplexpolymeren: [M(oxm)(H2O)2]x; (M = Cu, Zn, Cd), [Co(oxm)(H2O)2]x·0.5xH2O und [Ni(oxm)(H2O)2]x·xH2O, wird vorgestellt. Ethyloxamat kann auch für die Herstellung von monomeren Oxamato(-1)-Komplexen verwendet werden.

Coordination compounds of N-(2-aminophenyl)- and N-(3-aminophenyl)pyridine-2′-carboxamide with cobalt(II) and cobalt(III). The nature of amide deprotonation induced by cobalt(III) in acidicpH

New complexes of the general formulae CoL2X·nH2O (X=Cl, Br, I, NCS, NO3 andn=0, 1, 2 or 3), Co2L2X3·EtOH (X=Cl, Br, I, NCS), Co(DH)X2 (X=NCS, NO3) and Co(DH)2X2 (X=NCS, I) have been prepared, whereLH=N-(2-aminophenyl)pyridine-2′-carboxamide andDH=N-(3-aminophenyl)pyridine-2′-carboxamide. The compounds were characterized by X-ray powder patterns, conductivity measurements, thermogravimetric analysis, magnetic properties as well as by IR, ligand field and1H-NMR spectroscopy. In the presence of oxygen,LH undergoes a cobalt(III) ion promoted amide hydrogen ionization in thepH region 4–6.ZusammenfassungNeue Komplexe der allgemeinen Formeln CoL2X·nH2O (X=Cl, Br, I, NCS, NO3 undn=0, 1, 2, 3), Co2L2X3·EtOH (X=Cl, Br, I, NCS), Co(DH)X2 (X=NCS, NO3) und Co(DH)2X2 (X=NCS, I) wurden dargestellt mit LH=N-(2-aminophenyl)pyridin-2′-carboxamid undDH=N-(3-aminophenyl)pyridin-2′-carboxamid. Die Verbindungen wurden mittels Röntgenstrukturanalyse, Leitfähigkeitsmessungen, thermogravimetrischen Analysen, magnetischen Eigenschaften sowie mit IR-, Ligandenfeld- und1H-NMR-Spektroskopie charakterisiert. In Gegenwart von Sauerstoff unterliegtLH einer Cobalt(III)ion-induzierten Amidwasserstoffionisierung impH-Bereich 4–6.

Metal complexes of the diuretic drug furosemide

New complexes of the formulaeM(fur)2·2H2O (M = Mn, Cu, Zn),M(fur)2·3H2O (M = Co, Ni, Cd), Hg2(fur)3Cl2·2H2O, Pd(fur)Cl·H2O and Rh(fur)3·3H2O, wherefurH = 4-chloro-N-(2-furfuryl)-5-sulfamoylanthranilic acid, have been prepared and characterized by conductivity measurements, X-ray powder patterns, thermal methods, effective magnetic moments as well as by IR, ligand field,1H-NMR and ESR spectroscopic studies. The anionfur− shows a chelated bidentate O(carboxylato), N(imino)-coordinating behaviour.ZusammenfassungNeue Komplexe der Verbindungen:M(fur)2·2H2O (M = Mn, Cu, Zn),M(fur)2·3H2O (M = Co, Ni, Cd), Hg2(fur)3Cl2·2H2O, Pd(fur)Cl·H2O und Rh(fur)3·3H2O, wobeifurH 4-chlor-N-(2-furfuryl)-5-sulfamoylanthanilsäure ist, wurden dargestellt. Die Komplexe wurden durch Leitfähigkeitsmessungen, Röntgen-Pulver-Aufnahmen, thermogravimetrische Analysen, Messungen des effektiven magnetischen Dipolemomentes sowie durch spektroskopische Untersuchungen (IR,1H-NMR und ESR) charakterisiert. Das Anionfur− zeigt das Verhalten einer Chelat-bidentat-O(carboxylato),N(imino)-Koordination.

Bis(1-methylbenzotriazole)dinitratocobalt(II): A pseudo-octahedral complex with pseudo-tetrahedral magnetochemical and ligand field characteristics

SummaryThe reaction between cobalt(II) nitrate and 1-methylbenzotriazole (MeBTA) leads to a complex with unusual magnetochemical and ligand field characteristics. The synthesis and the physical and spectroscopic properties of the pseudo-octahedral complex [Co(MeBTA)2(NO3)2] are described.ZusammenfassungDie Reaktion zwischen Kobalt(II)nitrat und 1-Methylbenzotriazol (MeBTA) führt zu einem Komplex mit ungewöhnlichen magnetochemischen und Ligandenfeld-Eigenschaften. Die Synthese und die spektroskopischen Eigenschaften des pseudo-octaedrischen Komplexes [Co(MeBTA)2(NO3)2] werden beschrieben.

Synthesis and characterization of the complexes of lanthanide(III) chlorides and nitrates with the tetradentate schiff base diethyl(ethylenebis-β-aminocrotonate)

SummaryThe Schiff base ligand diethyl(ethylenebis-β-aminocrotonate) (LH2) reacts with lanthanide(III) chlorides and nitrates in various solvents to give solid complexes of the stoichiometriesLn(LH2)Cl3 (Ln=La−Yb),Ln(LH2)2Cl3 (Ln=La−Sm),Ln2(LH2)3Cl6(Ln=Eu−Yb) andLn(LH2)(NO3)3 (Ln=La−Yb). Properties, conductivity measurements, X-ray powder patterns, thermal data, magnetic moments and spectroscopic (IR,1H-NMR, electronic diffuse reflectance and solid state emission f-f spectra) are discussed in terms of the nature of the bonding and the possible structural types.ZusammenfassungDer Schiffbasen-Ligand Diethyl(ethylenbis-β-aminocrotonat) reagiert mit Lanthanid(III)chloriden und -nitraten in verschiedenen Lösungsmitteln unter der Bildung von festen Komplexen der StöchiometrienLn(LH2)Cl3 (Ln = La − Yb),Ln(LH2)2Cl3 (Ln = La − Sm),Ln(LH2)3Cl6 (Ln = Eu − Yb) undLn(LH2)(NO3)3 (Ln = La − Yb). Die allgemeinen Eigenschaften, Leitfähigkeitsmessungen, Röntgen-Pulverdiagramme, thermische Daten, magnetische Momente und spektroskopische Daten (IR,1H-NMR, Elektronenreflexionsspektren und Festkörperemissions-f-f-Spektren) werden im Hinblick auf die Bildungsverhältnisse im Komplex und strukturelle Möglichkeiten diskutiert.

Pseudotetrahedral cobaltate(II) anions with two and three different kinds of ligands

New complexes of the general types HCo(NCS)3 ·nL, HCoX2(NCS) ·nL and HCo(NCS)2I ·nL (whereX=Cl, Br, I;L=diethyl ether, pyridine, aniline;n=1.5, 2, 3, 3.5) have been prepared and characterized. The magnetic and spectroscopic data indicate that pseudotetrahedral [Co(NCS)3L]−, [CoX2(NCS)L]− and [Co(NCS)2IL]− anions are present in the solid pyridine and aniline compounds.ZusammenfassungNeue Komplexe der allgemeinen Formeln HCo(NCS)3 ·nL, HCoX2(NCS) ·nL und HCo(NCS)2I ·nL (wobeiX=Cl, Br, I;L=Diethylether, Pyridin, Anilin;n=1,5, 2, 3, 3,5) wurden dargestellt und charakterisiert. Die magnetischen und spektroskopischen Ergebnisse weisen darauf hin, daß in den festen Pyridin- und Anilin-Komplexen pseudotetraedrische [Co(NCS)3L]−-, [CoX2(NCS)L]−- und [Co(NCS)2IL]−-Anionen vorliegen.