Isolation and Characterization of a Homoleptic Tetramethylcobalt(III) Distorted Square-Planar Complex

Substitution of an acetylacetonate by a carboxylate in the neutral (acac)2Cu(II) was achieved by its reaction with tri- and dichloroacetic acid in benzene (HCO2R where R = CCl3 or CHCl2; Hacac = acetylacctone) which led to the formation of the mixed chelate square planar complex (acac)Cu(OCOR). The later complex, R = CCl3, reacted with heterocyclic bases to produce the square pyramidal complexes (acac)Cu(OCOR) (base), (base = 2- methylpyridine or quinoline); with ethylenediamine (en) to give the octahedral [(en)2Cu(OCOR)]Cl, and with methanol and piperidine or boiling methanol alone to give the methoxo-bridged (acac)Cu(OCH3)2Cu(acac). The reaction of acetylacetonate-carboxy- late-copper(II) complex (R = CHCl2) with heterocyclic bases led to the cleavage of the acetylacetonate ligand and the formation of the octahedral Cu(OCOCHCl2) · 2 base (base = pyridine, 2-, 3- or 4-methylpyridine). The same cleavage reaction took place, and also with R = CCl3, in their reaction with 8-hydroxyquinoline to form the mixed chelates (ROCO)Cu(Oxinate). These formulations are based on chemical analyses, electronic and vibrational spectra, and on conductance measurements.

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Isolation and characterization of (PNP)2Co(CN)4, an unusual square-planar tetracyanocobalt(II) complex

Journal of the American Chemical Society ◽

10.1021/ja00327a033 ◽

1984 ◽

Vol 106 (15) ◽

pp. 4265-4266 ◽

Cited By ~ 11

Author(s):

Stephen J. Carter ◽

Bruce M. Foxman ◽

Louis S. Stuhl

Keyword(s):

Isolation And Characterization ◽

Square Planar

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Isolation and characterization of polydentate ligands derived from the reaction of pentaerythrityltetrabromide and ethylenediamine

Canadian Journal of Chemistry ◽

10.1139/v89-254 ◽

1989 ◽

Vol 67 (10) ◽

pp. 1657-1665 ◽

Cited By ~ 14

Author(s):

A. McAuley ◽

K. Beveridge ◽

S. Subramanian ◽

T. W. Whitcombe

Keyword(s):

Diethyl Malonate ◽

Ring Closure ◽

Polydentate Ligands ◽

Isolation And Characterization ◽

Free Amine ◽

Square Planar ◽

Bonding Interaction ◽

Hydrolysis Of ◽

Amine Hydrochlorides

Reaction of pentaerythrityltetrabromide with ethylenediamine yields three product amines. These have been isolated by separation of the corresponding Ni2+ complexes. The free amine hydrochlorides have been obtained by acid hydrolysis of the Ni2+ species and have been characterized by nuclear magnetic resonance and mass spectroscopy. The crystal structures have been determined for the hexahydrochloride salt of polyamine ligand L1, [H6(L1)]Cl6•4H2O (L1 = C11H28N6, 6,6-bis(4-amino-2-azabutyl)-1,4-diazacycloheptane)(C2/c, a = 15.975) Å, b = 10.723 (1) Å, c = 14.686(1) Å, β = 99.40(1)°, Z = 4), and for the octahydrochloride salt of L2, [H2(L2)Cl8•2H2O (L2 = 5,5-bis(4-amino-2-azabutyl)-1,9-diamino-3,7-diazanonane) (Pccn, a = 12.834(2) Å, b = 16.691(1) Å, c = 14.167(1) Å, Z = 4). Both crystals exhibit strong N—H … Cl,O,N bonding, although in the latter compound the waters of crystallization do not participate in the apparent hydrogen bonding interaction. Both these species are of interest since they represent the precursors to square planar Ni2+ complexes that incorporate the MN4 chromophore. Ring closure of both the free amines L1 and L2 by reaction with diethyl malonate leads to cyclized products that are related to the cyclam ([14-aneN4) tetraaza macrocylic ligands. Keywords: pentaerythrityl, amine, spiro ligand hydrochlorides.

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