M. Shakir

Macrocyclic complexes of transition metals with divalent polyaza units

A new series of 14–16-membered hexaazamacrocyclic complexes [ML1X2] and [ML2X2] (M = CoII, NiII, CuII and ZnII; X = Cl or NO3) have been synthesized by template condensation of phenylenediamine, primary diamines and formaldehyde solution 35% in MeOH and have been characterized by i.r., 1H-n.m.r., e.p.r., and u.v. spectroscopy as well as by magnetic susceptibility and conductivity measurements. An octahedral geometry has been suggested for all the complexes.

Metal ion directed synthesis of 14–16 membered tetraimine macrocyclic complexes

A new series of 14–16 membered tetraazatetraimine macrocyclic complexes [ML1X2]-[ML3X2] [M=CoII, NiII and ZnII] and [CuL1]X2-[CuL3]X2 [X=Cl or NO3] have been synthesized by the template condensation of dibenzoylmethane with primary diamines in MeOH. The complexes were characterized by elemental analysis, i.r, 1H-n.m.r., e.p.r. and u.v-vis spectroscopy, as well as by conductivity and magnetic susceptibility measurements. The copper complexes exhibit square planar geometry, whereas an octahedral geometry is suggested for all other complexes.

Synthesis and Characterization of bis(Macrocyclic) Complexes Based on the 13-Membered Pentaaza Unit

Abstract The template condensation of triethylenetetraamine, formaldehyde and benzidine in 2:4:1 molar ratio results in new types of binuclear bis(macrocyclic) complexes, [M2LX4] [M = Mn, Co, Ni, Cu, Zn, X = Cl or NO3] in which two pentaazacyclotetradecane subunits are linked by a biphenyl group attached to an uncoordinated benzidine nitrogen atom. The complexes synthesized were characterized by IR, 1H NMR, UV/VIS, EPR, conductivity, magnetic moments and analytical data. The observed low conductance values of all these complexes suggests their non-ionic character and that all the complexes exhibit octahedral geometry around the metal ions. Referee I: E. Rosenberg Referee II: K. Moedritzer

3-mercapto-1,2-propanediol and its 1-methoxy and 1-ethoxy derivatives, HSCH2CH(OH)CH2OR′ (R′= H, CH3, C2H5), as uninegative bidentate bridging ligands: Synthesis and characterization of dimeric complexes with cobalt, copper and silver

Abstract Reaction of 3-mercapto-1,2-propanediol and its 1-methoxy and 1-ethoxy derivatives, HSCH 2 CH(OH)CH 2 OR′(R′= H, CH 3 , C 2 H 5 ) [RSH, R = CH 2 CH(OH)CH 2 OR′], with [M(PPh 3 ) 3 X] [M = Co I , Cu I ; X = Cl or Ag I ; X = NO 3 ] in tetrahydrofuran yield bridged dimeric species, [M(PPh 3 ) 2 RS] 2 [R = CH 2 CH(OH)CH 2 OR′; M = Co I ( 1 ), Cu I ( 2 ), Ag I ( 3 ); 1a, 2a, 3a and 1b, 2b, 3b for R′ = H, CH 3 and C 2 H 5 , respectively]. The complexes corresponding to Co I and Cu I are also prepared by reaction with [M(PPh 3 ) 2 Cl 2 ] under similar reaction conditions, [M(PPh 3 ) 2 RS] 2 [M = Co ( 1′ ), Cu ( 2′ ); 1a′ , 2a′ and 1b′ , 2b′ for R = H, CH 3 , C 2 H 5 , respectively], where the metal ions reduce to their corresponding monovalent states.

Organotellurium Derivatives. Syntheses and Characterization of Dimethyl and Diethyl Telluriumdichlorosulphates [R2Te(SO3Cl)2]

Abstract Dimethyl and diethyl telluriumdichlorosulphates have been isolated in the form of dark brown colored crystalline solids utilizing the solvolytic reactions of the corresponding di-iodides with chlorosulphuric acid. The electrical conductivity and IR spectroscopic studies confirm that these compounds are non-ionic and the mode of linking of the chlorosulphate group to the tellurium atom is covalent, resulting in a reduced Cs symmetry for the chlorosulphate group. The PMR spectral study indicates that the corresponding methyl and ethyl protons of these molecules are deshielded which is consistent with the lowering of the non-bonded electron density at tellurium atom due to its drainage towards the chlorosulphate group.

Coordinating Properties of Chlorosulphate Ion; Synthesis and Characterization of Mn (II), Co (II), Ni(II) and Cu(II) Bis-(Chlorosulphates) and Their Complexes with Nitrogen-Containing Bases

Abstract Chlorosulphates of the divalent transition metals Mn(II), Co(II), Ni(II) and CU(II) have been prepared and characterized. The electrical conductivities and i.r. spectral data indicate a considerable extent of cation-anion interaction and the anion is bonded in a tridentate manner such that it has a reduced Cs symmetry in the molecule. The magnetic susceptibility measurements and the ligand field spectroscopic studies are consistent with the octahedral geometry for these salts and indicate the presence of some covalent bonding between the chlorosulphate ion and the metal ion. However, a tetragonal distortion in the geometry has been indicated for the Ni(II) salt. The coordination compounds of the type ML4(SO3Cl)2[L=acetonitrile, pyridine, pyridine N-oxide] and ML2(SO3Cl)2 [L = 2,2′bipyridine, acridine] have also been prepared and characterized. The i.r. and ligand field spectroscopic studies and magnetic susceptibility measurements indicate the presence of a strong interaction between the anion an...

3,4-Dicyano-5-aminopyrazole complexes of anhydrous divalent transition metal chlorides and their triphenylphosphine derivatives

Summary3,4-Dicyano-5-aminopyrazole, H3,4(CN)25NH2pz (L) reacts either with anhydrous MCl2 or with [M(PPh3)2Cl2] to yield ML4Cl2 complexes (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd or Hg), whose monomeric and covalent natures have been confirmed by their solubility in most non-polar solvents and their low electrical conductivities. The bonding mode of substituted pyrazole is inferred from the position of the ν(C-N) band in the i.r. spectra. The electronic spectra and the magnetic moments of these compounds were recorded.

Metal Complexes of 22-Niembered Mononuclear Tetraimine-Tetraamide Macrocycles: Synthesis and Characterization

Abstract Template condensation reaction of succinic acid or phthalic acid with hydrazine hydrate and 2,4-pentanedione resulted in the formuation of a new series of 22-membered tetraiminetetraamide macrocyclic complexes: dichloro/dinitrato (8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)metal(II), [ML1X2] [M = Mn(II), Co(II), Ni(II) and Zn(II); X = CI or NO3]; (8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)copper(II) dichloride/dinitrate [CuL1]X2; dichloro/dinitrato(9, 10, 20, 21-d ibenzo-8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl-1, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)metal(II), [ML2X2] [M = Mn(II), Co(II), Ni(II) and Zn(II); X = CI or NO3) and (9, 10, 20, 21-dibenzo-8, 11, 19, 22-tetraone-3, 5, 14, 16-tetramethyl, 2, 6, 7, 12, 13, 17, 18-octaazacyclodocosane-2, 5, 13, 16-tetraene)copper(II) dichloride/dinitrate, [CuL2]X2. These complexes have been characterized by IR, 1H NMR, EPR and electronic spectral studies, conductivity and magnetic susceptibility measurements. An octahedral geometry has been suggested for the manganese, cobalt, nickel and zinc complexes, while a square-planar geometry is proposed for the copper complexes. All complexes are stable to air.

Organotellurium(IV) derivatives: Synthesis and characterization of metal dialkyltetrakis(chlorosulphato)tellurate(IV), M2[R2Te(SO3Cl)4] (M Na, K) and Sn[R2Te(SO3Cl)4] (R CH3, C2H5, n-C3H7, n-C4H9

Abstract The ability of R2Te(SO3Cl)2 (R  CH3, C2H5, n-C3H7, n-C4H9) compounds to behave as a SO3Cl− acceptors has been proved by the synthesis and characterization of new monomeric complexes of the type M2[R2Te(SO3Cl)4] (M Na, K) and Sn[R2Te(SO3Cl)4] by reacting stoichiometric amounts of R2TeI2 (R  CH3, C2H5, n-C3H7, n-C4H9) with metal salts, namely NaI, KI and SnCl2, in excess HSO3Cl. The compounds are hygroscopic in nature but are stable under dry nitrogen. The IR spectra of the compounds suggest that the SO3Cl− is covalently bonded to the dialkyltellurium moiety. The observed molar conductance values of these compounds in DMSO confirm that they are 1:1 and 1:2 electrolytes. The 1H NMR spectra are discussed in terms of inductive effects and since the chlorosulphate group is expected to be bound in monodentate manner the hexacoordination around the tellurium atom is maintained.

Synthesis and Characterization of Metal Mono (Chlorosulphates) M(SO3CL) [M = Ag(I) and Hg(I)] and Their Complexes with Organic Donor Bases

Abstract The solvolytic reaction of silver(I) acetate and mercury(I) chloride in chlorosulphuric acid afforded Ag(SO3Cl) and Hg2(SO3Cl)2, respectively, where HSO3Cl acts both as medium of reaction as well as chlorosulphonating agent. These compounds are hygroscopic in nature and dissolve in non-polar solvents. The coordinating ability of the SO3Cl− group has been further investigated by synthesizing the complexes of these metal monochlorosul phates with strong donor organic bases leading to the formation of complexes of the types [M(SO3Cl)L3] [L = triphenylphosphine, pyridine, pyridine N-oxide] and [M(SO3Cl)L] [L = 2,2′-bipyridine, acridine]. The SO3Cl− group has been found to be covalently bonded to the metal ions or the complex cations [MLn]+ as evidenced by the shift to higher frequency of ν1(A), splitting of doubly degenerate (E) modes and low values of electrical conductivities. The magnetic moment measurements indicate their diamagnetic nature. Referee I: J. A. Heppert Referee II: G. C. Defotis