A single H-bond triggers the formation of a cleft around EtNH through bond rearrangement and rotations of arms in both Co(III) and Fe(III) complexes.

The single H-bond capable N-H in triethylammonium triggers massive structural rearrangement in an inert Co(III) complex that tetraethylammonium cannot. The rearrangement provides a new way to distinguish two similar cations spectroscopically. The process is identical and instantaneous with labile iron(III) without any spectroscopic change.

Water-soluble chiral coordination polymers of Li, Na, K, and Ba with an anionic iron(III) complex of a L-threonine derivative and a significant red shift of visible spectra with Al salt.

Four salts of an anionic iron(III) bis-complex, [Fe(L)], were synthesized from water or methanol. HL is a tridentate ligand derived from the L-threonine amino acid, and the cations used are Li (1), Na (2), K (3), and Ba (4). Single-crystal X-ray diffraction showed that all the complexes are coordination polymers of different dimensionalities.

Characterization of a meso-chiral isomer of a hexanuclear Cu(II) cage from racemization of the L-alanine Schiff base.

We are reporting structural characterization of two new hexanuclear cages (H3O)2[Cu3(μ3-OH)(μ3-NH3)(0.5)(L)3]2·8H2O (1) and (H3O)2[Cu3(μ3-OH)(μ3-H2O)(0.5)(L)3]2·8H2O (1a) where L(2-) is the dianionic form of the Schiff base of L-alanine and salicylaldehyde.

Sodium and potassium ion directed self-assembled multinuclear assembly of divalent nickel or copper and L-leucine derived ligand.

L-leucine derived ligand (H(2)L(L-leu)), KOH, and Ni(II) salt in 2:2:1 ratio self-assembled into a rather large (approximately 13 A) supramolecular assembly with the formula [K{Ni(HL(L-leu))(2)}(3)](+) (1). Structural characterization showed three [Ni(HL(L-leu))(2)] units encapsulated K(+) similar to organic crown ethers/cryptand. Substituting Ni(II) with Cu(II) and K(+) with Na(+) in the above reaction resulted in a set of structurally identical assemblies with the general formula [M'{M(HL(L-leu))(2)}(3)](+), where M' is either K(+) or Na(+) and M is either Cu(II) or Ni(II); [Na{Ni(HL(L-leu))(2)}(3)]ClO(4) (2), Na{Ni(HL(L-leu))(2)}(3)]OTf (3), [K{Cu(HL(L-leu))(2)}(3)]ClO(4) (4), [Na{Cu(HL(L-leu))(2)}(3)]ClO(4) (5), [K{Cu(HL(L-leu))(2)}(3)]NO(3) (6).

Formation of a narrow chiral cavity in bis-copper(ii) complexes of ferrocenylmethyl-l-tyrosine and its interaction with achiral guests.

Earlier we reported the tendency of ferrocenylmethyl substituted amino acids to organize around Cu(ii) in a C(2) symmetry. In this paper we have utilized this property to form a chiral cavity using a l-tyrosine derivative. Structural characterization of [Cu(II)(S-fTyr)(2)(MeCN)(2)] (), where S-fTyr(1-) is ferrocenylmethyl-l-tyrosinate, showed that the alignment of two tyrosine aromatic rings around the fifth coordination site generates a narrow cavity.

Cu(II)-mediated synthesis of a new fluorescent pyrido[1,2-a]quinoxalin-11-ium derivative.

Quinoxalines are heterocyclic compounds with potential application as drugs or fluorophores. However, few quinoxalinylium salts have been reported in the literature. This manuscript describes the synthesis and structural characterization of a previously unknown quinoxalinylium derivative, 2-aminopyrido[1,2-a]quinoxalin-11-ylium ([1](+)), as perchlorate and thiocyanate salts from the Cu(II)-mediated reaction of a Schiff base.

Ferrocene substitution in amino acids strengthens the axial binding in Cu(II) complexes and separates the hydrophobic and hydrophilic region in the crystals.

This paper reports on the synthesis, characterization and electrochemical properties of four ferrocenylmethyl substituted L-amino acid ligands and their Cu(II) complexes. Structural characterization of the complexes of L-methionine and L-asparagine derived ligands showed axial coordination of weak thioether and amide respectively to Cu(II). Coordination of the thioether group of L-methionine to copper (2.

Hexavalent chromium removal from wastewater using aniline formaldehyde condensate coated silica gel.

A resinous polymer, aniline formaldehyde condensate (AFC) coated on silica gel was used as an adsorbent in batch system for removal of hexavalent chromium from aqueous solution by considering the effects of various parameters like reaction pH, dose of AFC coated silica gel, initial Cr(VI) concentration and aniline to formaldehyde ratio in AFC synthesis. The optimum pH for total chromium [Cr(VI) and Cr(III)] adsorption was observed as 3. Total chromium adsorption was second order and equilibrium was achieved within 90-120 min.

Structural characterization of an enantiopure hydroxo-bridged binuclear iron(III) complex with empty one-dimensional helical channels.

A H-bond capable chiral tetradentate ligand, Fe3+, and acetate ion assembles into a hydroxo-bridged binuclear complex with the formula [FeIII2(mu-OH)(mu-OAc)(S-L)2] x 4H2O (1) where H2S-L = S-2-(2-hydroxy-benzylamino)-3-(1H-imidazol-4-yl)-propionic acid. The crystal of 1 contains right-handed one-dimensional (1D) helical channels with 7.3-9.

Role of carboxylate bridges in modulating nonheme diiron(II)/O(2) reactivity.

A series of diiron(II) complexes of the dinucleating ligand HPTP (N,N,N',N'-tetrakis(2-pyridylmethyl)-2-hydroxy-1,3-diaminopropane) with one or two supporting carboxylate bridges has been synthesized and characterized. The crystal structure of one member of each subset has been obtained to reveal for subset A a (micro-alkoxo)(micro-carboxylato)diiron(II) center with one five- and one six-coordinate metal ion and for subset B a coordinatively saturated (micro-alkoxo)bis(micro-carboxylato)diiron(II) center. These complexes react with O(2) in second-order processes to form adducts characterized as (micro-1,2-peroxo)diiron(III) complexes.