@article {5202,
	title = {Effects of sequential replacement of -NH2 by -OH in the tripodal tetraamine tren on its acidity and metal ion coordinating properties},
	journal = {Inorganic Chemistry},
	volume = {40},
	number = {7},
	year = {2001},
	note = {ISI Document Delivery No.: 413ATTimes Cited: 26Cited Reference Count: 32},
	month = {Mar},
	pages = {1527-1535},
	type = {Article},
	abstract = {The preparation is described of two modified derivatives of the tripodal tetraamine tren, 2-hydroxy-N,N-bis(2-aminoethyl)ethylamine, NNO(2)222, and 2-amino-N,N-bis(2-hydroxyethyl)ethylamine NNO(2)222, in which one and two primary amines, respectively, have been replaced with hydroxyl groups. The aqueous acid-base and metal ion (Ni2+, Cu2+: Zn2+ coordination properties of these two compounds were studied by potentiometric, spectrophotometric, and NMR titrations. Two and three acidity constants, respectively, were determined for NNO(2)222 and NN(2)O222 by potentiometry. NMR titrations proved that deprotonation of the two OH residues in NNO(2)222, and of the one in NN(2)O222, corresponded to pK(a) > 14. Acidity constants related to deprotonation-of the terminal primary amine functions were similar in both NNO2222 and NN(2)O222 land to those in the parent compound tren), whereas deprotonation of the tertiary ammonium N atom had a very different acidity constant in each of these three compounds. Charge repulsion, polar effects, and intramolecular hydrogen bond formation an responsible for the discrepancy. Chelated diamine metal complexes for each ligand studied depended only on the basicity of the corresponding two amines, suggesting that the hydroxyl group interacted with the metal ion very weakly in acidic or neutral solutions. The ML2+ species further deprotonated to form M(L - H)(+) and M(L - 2H) complexes, in which the protons are released from the coordinated OH group. A pM vs pH correlation showed that replacing an NH2 group with a OH group in tren or NN(2)O222 makes the resulting metal complex less stable. Electronic spectra showed that the Cu(II) complexes of both NNO(2)222 and NN(2)O222 adopted a square pyramidal geometry rather than a trigonal bipyramidal geometry. The X-ray crystal structure analysis of the zinc complex [Zn(OH)(mu -NNO(2)222 - H)Zn(NNO(2)222)](2+), as its [BF4](-) salt, shows a dinuclear molecule containing two zinc ions, each coordinated in a distorted trigonal bipyramid. The coordination environment at one zinc atom is composed of the four donor groups of a mono-O-deprotonated ligand NNO(2)222 and a hydroxyl ion with the central nitrogen atom of the ligand and the hydroxyl ion in equatorial positions. The oxygen atom of the deprotonated alkoxo group bridges to the second zinc atom, which is coordinated by this atom and one undeprotonated ligand NNO2222.},
	keywords = {COPPER(II) COMPLEXES, CRYSTAL, DIPERCHLORATE, donor ligands, STABILITY},
	isbn = {0020-1669},
	url = {<Go to ISI>://000167588300019},
	author = {Song, B. and Reuber, J. and Ochs, C. and Hahn, F. E. and Lugger, T. and Orvig, Chris}
}
@article {4116,
	title = {Transition metal azolates from metallocenes .2. Synthesis, X-ray structure, and magnetic properties of a three-dimensional polymetallic Iron(II) imidazolate complex, a low-temperature weak ferromagnet},
	journal = {Journal of the American Chemical Society},
	volume = {119},
	number = {37},
	year = {1997},
	note = {ISI Document Delivery No.: XW696Times Cited: 57Cited Reference Count: 49},
	month = {Sep},
	pages = {8675-8680},
	type = {Article},
	abstract = {{The reaction of ferrocene with molten imidazole at 150 degrees C yielded pale yellow crystals of composition [Fe-3(imid)(6)(imidH)(2)](x). Crystals of [Fe-3(imid)(6)(imidH)(2)](x) are monoclinic},
	keywords = {3, 5-DIMETHYLPYRAZOLATE, BRIDGED COMPLEXES, COPPER(II) COMPLEXES, CRYSTAL-STRUCTURE, DINUCLEAR COMPLEX, EXCHANGE INTERACTION, MOLECULAR-STRUCTURES, MONONUCLEAR, PYRAZOLATE POLYMERS, ROUTE},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1997XW69600011},
	author = {Rettig, S. J. and Storr, A. and Summers, D. A. and Thompson, R. C. and Trotter, J.}
}
@article {4116,
	title = {Transition metal azolates from metallocenes .2. Synthesis, X-ray structure, and magnetic properties of a three-dimensional polymetallic Iron(II) imidazolate complex, a low-temperature weak ferromagnet},
	journal = {Journal of the American Chemical Society},
	volume = {119},
	number = {37},
	year = {1997},
	note = {ISI Document Delivery No.: XW696Times Cited: 57Cited Reference Count: 49},
	month = {Sep},
	pages = {8675-8680},
	type = {Article},
	abstract = {{The reaction of ferrocene with molten imidazole at 150 degrees C yielded pale yellow crystals of composition [Fe-3(imid)(6)(imidH)(2)](x). Crystals of [Fe-3(imid)(6)(imidH)(2)](x) are monoclinic},
	keywords = {3, 5-DIMETHYLPYRAZOLATE, BRIDGED COMPLEXES, COPPER(II) COMPLEXES, CRYSTAL-STRUCTURE, DINUCLEAR COMPLEX, EXCHANGE INTERACTION, MOLECULAR-STRUCTURES, MONONUCLEAR, PYRAZOLATE POLYMERS, ROUTE},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1997XW69600011},
	author = {Rettig, S. J. and Storr, A. and Summers, D. A. and Thompson, R. C. and Trotter, J.}
}
@article {4116,
	title = {Transition metal azolates from metallocenes .2. Synthesis, X-ray structure, and magnetic properties of a three-dimensional polymetallic Iron(II) imidazolate complex, a low-temperature weak ferromagnet},
	journal = {Journal of the American Chemical Society},
	volume = {119},
	number = {37},
	year = {1997},
	note = {ISI Document Delivery No.: XW696Times Cited: 57Cited Reference Count: 49},
	month = {Sep},
	pages = {8675-8680},
	type = {Article},
	abstract = {{The reaction of ferrocene with molten imidazole at 150 degrees C yielded pale yellow crystals of composition [Fe-3(imid)(6)(imidH)(2)](x). Crystals of [Fe-3(imid)(6)(imidH)(2)](x) are monoclinic},
	keywords = {3, 5-DIMETHYLPYRAZOLATE, BRIDGED COMPLEXES, COPPER(II) COMPLEXES, CRYSTAL-STRUCTURE, DINUCLEAR COMPLEX, EXCHANGE INTERACTION, MOLECULAR-STRUCTURES, MONONUCLEAR, PYRAZOLATE POLYMERS, ROUTE},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1997XW69600011},
	author = {Rettig, S. J. and Storr, A. and Summers, D. A. and Thompson, R. C. and Trotter, J.}
}
@article {3558,
	title = {GALLIUM AND INDIUM COMPLEXES OF HEXADENTATE LIGANDS CONTAINING PENDANT PYRIDYL AND PHENOLATE GROUPS},
	journal = {Inorganic Chemistry},
	volume = {34},
	number = {11},
	year = {1995},
	note = {ISI Document Delivery No.: RA186Times Cited: 26Cited Reference Count: 42},
	month = {May},
	pages = {3057-3064},
	type = {Article},
	abstract = {{Gallium and indium complexes of N,N{\textquoteright}-bis(2-hydroxybenzyl)-N,N{\textquoteright}-bis(2-methylpyridyl)ethylenediami (H(2)bbpen), N,N{\textquoteright}-bis(S-bromo-2-hydroxybenzyl)-N,N-bis(2-methylpyridyl)ethylenediamin e (H(2)Bbbpen), and N,N{\textquoteright}-bis(5-chloro-2-hydroxybenzyl)-N,N-bis (2-methylpyridyl)ethylenediamine (H(2)Clbbpen) were prepared and characterized by spectroscopic techniques and crystallographic analyses. H(2)bbpen, H(2)Brbbpen, and H(2)Clbbpen were prepared in excellent yield by the reactions of 2-picolyl chloride with N,N{\textquoteright}-bis(2-hydroxybenzyl)ethylenediamine (H-2- bben),N,N{\textquoteright}-bis(S-bromo-2-hydroxybenzyl)ethylenediamine (HzBrbben), and N,N{\textquoteright}-bis(S-chloro-2-hydroxybenzyl)ethylenediamine (H(2)Clbben), respectively. Characterization of H(2)bbpen and its substituted analogs showed these compounds to be symmetrical about the ethylene moiety of the ethylenediamine backbone. This symmetry is maintained in the metal complexes of these compounds. There are six potential sites for coordination to a metal ion: two amine nitrogens, two phenolate oxygens, and two pyridyl nitrogens. A series of monocationic metal complexes were obtained from the reactions of Ga3+ and In3+ with H(2)bbpen, H(2)Brbbpen, and H(2)Clbbpen in the presence of 2 equiv of base (acetate). Crystals of [Ga(Clbbpen)]ClO4 are triclinic, of space group P ($) over bar 1, with 11.1563(6) Angstrom},
	keywords = {aluminum, COBALT(III), COORDINATION, COPPER(II) COMPLEXES, CRYSTAL-STRUCTURES, IONS, metals},
	isbn = {0020-1669},
	url = {<Go to ISI>://A1995RA18600036},
	author = {Wong, E. and Liu, S. and Rettig, S. J. and Orvig, Chris}
}
