the complex of ce(iii), [ ce (phensc) (h 0) ] (c10 ) , was synthesized using the phensc, a hexadentate ligand,2,9-diformyl-1,lo- phenanthroline bis (semicarbazone), and characterized by x-ray diffraction. the cerium atom has an unusual coordination number of ten involving six donor atoms of the planar ligand in the equatorial plane and four oxygen atoms from four axial water molecules. the comp...

High-frequency, high-field EPR at 330 GHz was used to study the photo-oxidized primary donor of photosystem I (P(700)(+)(*)) in wild-type and mutant forms of photosystem I in the green alga Chlamydomonas reinhardtii. The main focus was the substitution of the axial ligand of the chlorophyll a and chlorophyll a' molecules that form the P(700) heterodimer. Specifically, we examined PsaA-H676Q, in...

Experimental work on the oxidation of the lignin model, syringyl alcohol, using oxygen and a Co(salen) catalyst has revealed variations in yield with different imidazole-based axial ligands. A reasonable linear relationship was found between product yield and pKa of the axial ligand. The current work, using density functional calculations, examined geometric, electronic, and energetic parameter...

In the title triangulo-triruthenium compound, [Ru(3)(C(6)H(12)Cl(3)O(3)P)(CO)(11)], one equatorial carbonyl ligand is substituted by a monodentate phosphite ligand, leaving one equatorial and two axial carbonyl ligands on one Ru atom. The remaining two Ru atoms each carry two equatorial and two axial terminal carbonyl ligands. In the crystal structure, the mol-ecules are linked into a one-dimen...

In the title compound, [Sn(C(7)H(7))(C(9)H(6)NO)(2)Cl], the Sn(IV) ion is in a distorted octa-hedral coordination environment formed by the O and N atoms of two bis-chelating quinolin-8-olate ligands, a Cl atom and a C atom from a benzyl ligand. The axial sites are occupied by an N atom of a quinolinate ligand and the C atom of the benzyl ligand. The axial Sn-N bond is slightly shorter than the...

A conserved histidine serves as the axial ligand to the Mg of bacteriochlorophylls in the photosynthetic reaction center (RC) and many other photosynthetic systems. The histidine axial ligands to each and both bacteriochlorophylls of the special-pair primary electron donor of the Rhodobacter sphaeroides RC have been replaced with glycine to create a cavity. In each case, RCs assemble and a norm...

A series of new heteroleptic chelated copper(II) complexes that encompass N,N-dibezyl substituted derivative of ethylenediamine (X-diamine) and acetylacetonate (acac) were prepared.  The IR and electronic absorption spectra and the molar conductivity of the complexes are presented and discussed.  The molar conductivity values of the complexes in different solvents reveals a predominance of elec...

The title compound, [Co(C(14)H(17)N(5))(C(6)H(7)N)](C(24)H(20)B) or [Co{(pyrrole)(2)dien}(4-Mepy)]BPh(4) where (pyrrole)(2)dien is 2,2'-[(3-aza-pentane-1,5-diylbis(nitrilo-methyl-idyne)]dipyrrole and 4-Mepy is 4-methyl-pyridine, contains a penta-dentate (pyrrole)(2)dien ligand furnishing an N(5) set, such that two of the pyrrole N atoms and two of the dien N atoms occupy the equatorial position...

Corrinoid (vitamin B12-like) cofactors contain various alpha-axial ligands, including 5,6-dimethylbenzimidazole (DMB) or adenine. The bacterium Salmonella enterica produces the corrin ring only under anaerobic conditions, but it can form "complete" corrinoids aerobically by importing an "incomplete" corrinoid, such as cobinamide (Cbi), and adding appropriate alpha- and beta-axial ligands. Under...

The rational design and syntheses of a new series of Os(II) complexes with formula [Os(fppz)(2)(CO)(L)] (1: L=4-dimethylaminopyridine; 2: L = pyridine; 3: L = 4,4'-bipyridine; 4: L = pyridazine; 5: L = 4-cyanopyridine), bearing two (2-pyridyl)pyrazolate ligands (fppz) together with one carbonyl and one N-heterocyclic ligand at the axial positions are reported. Single-crystal X-ray diffraction s...