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Beyramabadi SA, Morsali A, Vahidi SH, Khoshkholgh MJ, Esmaeili AA. N,N′-dipyridoxyl(ethylenediamine) schiff-base ligand and its square-pyramidal copper(II) complex: Synthesis, experimental and theoretical characterization. J STRUCT CHEM+ 2012. [DOI: 10.1134/s0022476612030079] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Grotjahn DB. Bifunctional catalysts and related complexes: structures and properties. Dalton Trans 2008:6497-508. [DOI: 10.1039/b809274e] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pal S, Barik AK, Gupta S, Hazra A, Kar SK, Peng SM, Lee GH, Butcher RJ, El Fallah MS, Ribas J. Copper(II) Mediated Anion Dependent Formation of Schiff Base Complexes. Inorg Chem 2005; 44:3880-9. [PMID: 15907114 DOI: 10.1021/ic0501420] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A tetranuclear mixed ligand copper(II) complex of a pyrazole containing Schiff base and a hydroxyhexahydropyrimidylpyrazole and copper(II) and nickel(II) complexes of the Schiff base having N-donor atoms have been investigated. A 2 equiv amount of 5-methyl-3-formylpyrazole (MPA) and 2 equiv of 1,3-diamino-2-propanol (1,3-DAP) on reaction with 1 equiv of copper(II) nitrate produce an unusual tetranuclear mixed ligand complex [Cu4(L1)2(L2)2(NO3)2] (1), where H2L1 = 1,3-bis(5-methyl-3-formylpyrazolylmethinimino)propane-2-ol and HL2 = 5-methyl-3-(5-hydroxyhexahydro-2-pyrimidyl)pyrazole. In contrast, a similar reaction with nickel(II) nitrate leads to the formation of a hygroscopic intractable material. On the other hand, the reaction involving 2 equiv of MPA and 1 equiv each of 1,3-DAP and various copper(II) salts gives rise to two types of products, viz. [Cu(T3-porphyrinogen)(H2O)]X2 (X = ClO4, NO3, BF4 (2)) (T3-porphyrinogen = 1,6,11,16-tetraza-5,10,15,20-tetrahydroxy-2,7,12,17-tetramethylporphyrinogen) and [Cu(H2L1)X]X x H2O (X = Cl (3), Br (4)). The same reaction carried out with nickel(II) salts also produces two types of compounds [Ni(H2L1)(H2O)2]X2 [X = ClO4 (5), NO3 (6), BF4 (7)] and [Ni(H2L1)X2] x H2O [X = Cl (8), Br (9)]. Among the above species 1, 3, and 5 are crystallographically characterized. In 1, all four copper atoms are in distorted square pyramidal geometry with N4O chromophore around two terminal copper atoms and N5 chromophore around two inner copper atoms. In 3, the copper atom is also in distorted square pyramidal geometry with N4Cl chromophore. The nickel atom in 5 is in a distorted octahedral geometry with N4O2 chromophore, where the metal atom is slightly pulled toward one of the axial coordinated water molecules. Variable-temperature (300 to 2 K) magnetic susceptibility measurements have been carried out for complex 1. The separations between the metal centers, viz., Cu(1)...Cu(2), Cu(2)...Cu(2)A, and Cu(2)A...Cu(1)A are 3.858, 3.89, and 3.858 A, respectively. The overall magnetic behavior is consistent with strong antiferromagnetic interactions between the spin centers. The exchange coupling constants between Cu(1)...Cu(2) and Cu(2)...Cu(2A) centers have turned out to be -305.3 and -400.7 cm(-1), respectively, resulting in a S = 1/2 ground state. The complexes are further characterized by UV-vis, IR, electron paramagnetic resonance, and electrochemical studies.
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Affiliation(s)
- Sachindranath Pal
- Department of Chemistry, SreeChaitanya College, Habra, North 24 Parganas, West Bengal, India
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Sallam SA. Synthesis, characterization and thermal decomposition of copper(II), nickel(II) and cobalt(II) complexes of 3-amino-5-methylpyrazole Schiff-bases. TRANSIT METAL CHEM 2005. [DOI: 10.1007/s11243-004-5859-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Liu YN, Orlowski G, Schatte G, Kraatz HB. 3-Ferrocenylamido-5-methylpyrazole: synthesis and metal coordination. Inorganica Chim Acta 2005. [DOI: 10.1016/j.ica.2004.11.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Grotjahn DB, Van S, Combs D, Lev DA, Schneider C, Incarvito CD, Lam KC, Rossi G, Rheingold AL, Rideout M, Meyer C, Hernandez G, Mejorado L. Substituent control of hydrogen bonding in palladium(II)-pyrazole complexes. Inorg Chem 2003; 42:3347-55. [PMID: 12739977 DOI: 10.1021/ic026104n] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Inter- and intramolecular hydrogen bonding of an N-H group in pyrazole complexes was studied using ligands with two different groups at pyrazole C-3 and C-5. At C-5, groups such as methyl, i-propyl, phenyl, or tert-butyl were present. At C-3, side chains L-CH(2)- and L-CH(2)CH(2)- (L = thioether or phosphine) ensured formation of chelates to a cis-dichloropalladium(II) fragment through side-chain atom L and the pyrazole nitrogen closest to the side chain. The significance of the ligands is that by placing a ligating side chain on a ring carbon (C-3), rather than on a ring nitrogen, the ring nitrogen not bound to the metal and its attached proton are available for hydrogen bonding. As desired, seven chelate complexes examined by X-ray diffraction all showed intramolecular hydrogen bonding between the pyrazole N-H and a chloride ligand in the cis position. In addition, however, intermolecular hydrogen bonding could be controlled by the substituent at C-5: complexes with either a methyl at C-5 or no substituent there showed significant intermolecular hydrogen bonding interactions, which were completely avoided by placing a tert-butyl group at C-5. The acidity of two complexes in acetonitrile solutions was estimated to be closer to that of pyridinium ion than those of imidazolium or triethylammonium ions.
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Affiliation(s)
- Douglas B Grotjahn
- Department of Chemistry, 5500 Campanile Drive, San Diego State University, San Diego, CA 92182-1030, USA.
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Grotjahn DB, Van S, Combs D, Lev DA, Schneider C, Rideout M, Meyer C, Hernandez G, Mejorado L. New flexible synthesis of pyrazoles with different, functionalized substituents at C3 and C5. J Org Chem 2002; 67:9200-9. [PMID: 12492321 DOI: 10.1021/jo026083e] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Syntheses of pyrazoles featuring a functionalized side chain attached to carbon 3 and varying alkyl and aryl substituents attached to carbon 5 are presented. Installation of R = methyl, isopropyl, tert-butyl, adamantyl, or phenyl groups at C5 is reported here, starting by coupling protected alkynols with acid chlorides RCOCl, forming alkynyl ketones, which are reacted with hydrazine to form the pyrazole nucleus. Alcohol deprotection and conversion to a chloride gave 5-substituted 3-(chloromethyl)- or 3-(2-chloroethyl)pyrazoles. This sequence can be done within 2 d on a 30 g scale in excellent overall yield. Through nucleophilic substitution reactions, the chlorides are useful precursors to other polyfunctional pyrazoles. In the work here, derivatives with side chains LCH(2)- and LCH(2)CH(2)- at C3 (L = thioether or phosphine) were made as ligands. The significance of the ligands made here is that by placing a ligating side chain on a ring carbon (C3), rather than on a ring nitrogen, the ring nitrogen not bound to the metal and its attached proton will be available for hydrogen bonding, depending on the steric environment created by R at C5.
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Affiliation(s)
- Douglas B Grotjahn
- Department of Chemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA.
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Paul S, Barik AK, Peng SM, Kar SK. Novel copper(II) induced formation of a porphyrinogen derivative: X-ray structural, spectroscopic, and electrochemical studies of porphyrinogen complexes of Cu(II) and Co(III) complex of a trispyrazolyl tripodal ligand. Inorg Chem 2002; 41:5803-9. [PMID: 12401086 DOI: 10.1021/ic0112185] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Copper(II) complexes of a novel pyrazole containing porphyrinogen and cobalt(III) and zinc(II) complexes of a pyrazole containing tripodal ligand having N-donor atoms have been investigated. 5-Methyl-3-formylpyrazole (MPA) on reaction with copper(II) nitrate or perchlorate in the presence of tris(2-aminoethyl)amine (tren) forms novel pyrazole-based porphyrinogen complexes [Cu(T(3)-porphyrinogen)(H(2)O)](NO(3))(2) (1a) and [Cu(T(3)-porphyrinogen)(H(2)O)](ClO(4))(2) (1b) where T(3)-porphyrinogen is 1,6,11,16-tetraaza-5,10,15,20-tetrahydroxy-2,7,12,17-tetramethylporphyrinogen. The same products are also obtained when tren is replaced by triethylamine. By contrast, the reaction between MPA, tren, and cobalt(II) perchlorate produces the cobalt(III) complex [Co(HMPz(3)tren)]ClO(4) (2) derived from the tripodal Schiff base tris[4-(3-(5-methyl-pyrazolyl)-3-aza-3-butenyl]amine (H(3)MPz(3)tren). The X-ray crystal structures of the copper(II) complexes (1a and 1b) and the cobalt(III) complex (2) have been determined. The structures show distorted square pyramidal coordination environments for 1a and 1b with the water molecule occupying the apical site, while for complex 2 a distorted octahedral geometry is obtained. Data for 1a follow: a = 19.476(3) A, b = 9.4116(8) A, c = 14.204(3) A; alpha = 90 degrees = gamma, beta = 107.58(2) degrees; V = 2482.0(7) A(3), Z = 4. Data for 1b follow: a = 20.967(3) A, b = 9.1563(18) A, c = 14.858(4) A; alpha = 90 degrees = gamma, beta = 108.44(3) degrees; V = 2706.0(10) A(3), Z = 4. Data for 2 follow: a = 21.293(3) A, b = 12.724(2) A, c = 19.777(4) A; alpha = 90 degrees = gamma, beta = 93.03(2) degrees; V = 5350.6(15) A(3), Z = 8. All three complexes crystallize in the monoclinic crystal system with the C2/c space group. The complexes are further characterized by UV-vis, IR, EPR, and electrochemical studies.
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Affiliation(s)
- Sachindranath Paul
- Department of Chemistry, SreeChaitanya College, Habra, North 24 Parganas, West Bengal, India
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Grotjahn DB, Van S, Combs D, Kassel WS, Rheingold AL. Hydrogen bonding in the crystal structure of bis{3-[(thiomethyl)methyl]pyrazole}copper(II) perchlorate. J Inorg Biochem 2001; 85:61-5. [PMID: 11377696 DOI: 10.1016/s0162-0134(00)00225-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ability of a metal-coordinated pyrazole to engage in hydrogen bonding has been explored by synthesis of the title complex, bis[3-([thiomethyl]methyl)pyrazole]copper(II) perchlorate (3). The coordination in 3 can be described as pseudo-octahedral, with two relatively tightly-bound 3-[(thiomethyl)methyl]pyrazole ligands occupying the equatorial plane, forming a [CuN(2)S(2)](2+) unit with the S donors mutually trans to each other. The axial positions are each filled by a weakly bound perchlorate counterion, one oxygen of which forms a hydrogen bond with the pyrazole N-H moiety on an adjacent [CuN(2)S(2)](2+) unit.
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Affiliation(s)
- D B Grotjahn
- Department of Chemistry, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182-1030, USA.
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Grotjahn DB, Combs D, Van S, Aguirre G, Ortega F. Synthesis and structure of isomeric palladium(II)-pyrazole chelate complexes with and without an N-H group as hydrogen bond donor. Inorg Chem 2000; 39:2080-6. [PMID: 12526516 DOI: 10.1021/ic990995q] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Four new ligands containing a pyrazole ring and either a phosphine or thioether were prepared and converted to their cis-dichloropalladium(II) complexes. Two of the ligands are especially notable for the attachment of a side chain at pyrazole carbon, rather than at nitrogen. The new metal complexes include dichloro[3-(diphenylphosphinomethyl)pyrazole]palladium(II) (1-PdCl2) and dichloro[3-(methylthiomethyl)pyrazole]palladium(II) (2-PdCl2), which both feature an N-H group as a potential proton or hydrogen bond donor. For comparison, isomeric complexes lacking an NH group were prepared: dichloro[1-(diphenylphosphinomethyl)pyrazole]palladium(II) (3-PdCl2) and dichloro[1-(methylthiomethyl)pyrazole]palladium(II) (4-PdCl2). As determined by X-ray crystallography, all four complexes were found to have slightly distorted square planar geometry. Complexes 1-PdCl2 and 2-PdCl2, which contain an NH group, exhibit both intermolecular and intramolecular hydrogen bonding, whereas isomers 3-PdCl2 and 4-PdCl2 do not. Single-crystal X-ray structure determinations on the following compounds are reported: 1-PdCl2, space group P1, a = 8.4488(9) A, b = 8.9175(13) A, c = 12.731(2) A, Z = 2, V = 871.8(2) A3; 2-PdCl2, space group Pbca, a = 10.8827(10) A, b = 11.7721(7) A, c = 14.874(2) A, Z = 8, V = 1905.6 A3; 3-PdCl2, space group P2(1)/c, a = 20.520(2) A, b = 12.549(2) A, c = 13.9784(13) A, Z = 8, V = 3401.1(6) A3; 4-PdCl2, space group Pbca, a = 10.6545(10) A, b = 12.0205(11) A, c = 14.6474(14) A, Z = 8, V = 1875.9(3) A3.
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Affiliation(s)
- D B Grotjahn
- Department of Chemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA.
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Synthesis, spectroscopic studies and solid state electrical conductivity of Ni(II) polymeric complexes. The crystal structure of the complex [Ni(L1)Cl2] · EtOH were L1=1,2-bis(2′-pyridylbenzyleneimino)benzene. Polyhedron 1998. [DOI: 10.1016/s0277-5387(98)00336-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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