Stabilization of different redox levels of a tridentate benzoxazole amidophenoxide ligand when bound to Co(iii) or V(v).

A tridentate benzoxazole-containing aminophenol ligand NNO was coordinated to Co and V metal centers and the electronic structure of the resultant complexes characterized by both experimental and theoretical methods. The solid state structure of the Co complex exhibits a distorted octahedral geometry with two tridentate ligands bound in meridional fashion, and coordination-sphere bond lengths consistent with a Co(iii) oxidation state. EPR and magnetic data support a S = 1/2 ground state, and a formal electronic description of Co(iii)(NNO)(NNO) where NNO corresponds to an amidophenoxide and NNO to the iminosemiquinone redox level.

Cyclometalation and coupling of a rigid 4,5-bis(imino)acridanide pincer ligand on yttrium.

An extremely rigid NNN-donor proligand, 4,5-bis{(diphenylmethylene)amino}-2,7,9,9-tetramethylacridan, H[AIm2] was prepared in five steps starting from 5-methyl-2-aminobenzoic acid and 4-bromotoluene. Reaction of intensely orange H[AIm2] with LiCH2SiMe3 formed deep blue Li(x)[AIm2]x (x = 2 in the solid state), while reaction with [Y(CH2SiMe3)3(THF)2] (0.5 equiv.

Increasing the bioavailability of Ru(III) anticancer complexes through hydrophobic albumin interactions.

A series of pyridine-based derivatives of the clinically successful Ru(III)-based complexes indazolium [trans-RuCl4(1H-indazole)2] (KP1019) and sodium [trans-RuCl4(1H-indazole)2] (KP1339) have been synthesized to probe the effect of hydrophobic interactions with human serum albumin (hsA) on anticancer activity. The solution behavior and protein interactions of the new compounds were characterized by using electron paramagnetic resonance (EPR) and UV/Vis spectroscopy. These studies have revealed that incorporation of hydrophobic substituents at the 4'-position of the axial pyridine ligand stabilizes non-coordinate interactions with hsA.

Synthesis, characterization and catalytic activity of copper(II) complexes containing a redox-active benzoxazole iminosemiquinone ligand.

A tridentate benzoxazole-containing aminophenol ligand HL(BAP) was synthesized and complexed with Cu(II). The resulting Cu(II) complexes were characterized by X-ray, IR, UV-vis-NIR spectroscopies, and magnetic susceptibility studies, demonstrating that the ligand is oxidized to the o-iminosemiquinone form [L(BIS)](-) in the isolated complexes. L(BIS)Cu(II)Cl exhibits a distorted tetrahedral geometry, while L(BIS)Cu(II)OAc is square pyramidal.

Optimization and structure-activity relationships of a series of potent inhibitors of methicillin-resistant Staphylococcus aureus (MRSA) pyruvate kinase as novel antimicrobial agents.

A novel series of hydrazones were synthesized and evaluated as inhibitors of methicillin-resistant Staphylococcus aureus (MRSA) pyruvate kinase (PK). PK has been identified as one of the most highly connected 'hub proteins' in MRSA. PK has been shown to be critical for bacterial survival which makes it a potential target for development of novel antibiotics and the high degree of connectivity implies it should be very sensitive to mutations and thus less able to develop resistance.

Gold(II) phthalocyanine revisited: synthesis and spectroscopic properties of gold(III) phthalocyanine and an unprecedented ring-contracted phthalocyanine analogue.

In 1965, gold(II) phthalocyanine (AuPc, 1) was described to be synthesized from unsubstituted 1,3-diiminoisoindoline and gold powder or AuBr. Compound 1 has been regarded as a rare example of a paramagnetic gold(II) complex. However, its chemistry, especially the oxidation state of the central gold ion, has not been previously explored due to the inherent insolubility of 1 caused by its unsubstituted structure.

From low to very high birefringence in bis(2-pyridylimino)isoindolines: synthesis and structure-property analysis.

A series of new substituted 1,3-bis(2-pyridylimino)isoindolines--1,3-bis(2-pyridylimino)-5,6-bis(2,6-diisopropylphenoxy)isoindoline (2b), 1,3-bis(2-pyridylimino)-5,6-bis(4-tert-butylphenyl)isoindoline (2c), and 1,3-bis(2-pyridylimino)-5-tert-butylisoindoline (2d)--were synthesized and structurally characterized by single-crystal X-ray diffraction. The birefringence (Δn) of the crystals of unsubstituted 1,3-bis(2-pyridylimino)isoindoline (2a), 2b, 2c, and 2d were measured and found to vary greatly, with Δn values of 0.0654(3), 0.

Pyridine analogues of the antimetastatic Ru(III) complex NAMI-A targeting non-covalent interactions with albumin.

A series of pyridine-based derivatives of the antimetastatic Ru(III) complex imidazolium [trans-RuCl(4)(1H-imidazole)(DMSO-S)] (NAMI-A) have been synthesized along with their sodium-ion compensated analogues. These compounds have been characterized by X-ray crystallography, electron paramagnetic resonance (EPR), NMR, and electrochemistry, with the goal of probing their noncovalent interactions with human serum albumin (hsA). EPR studies show that the choice of imidazolium ligands and compensating ions does not strongly influence the rates of ligand exchange processes in aqueous buffer solutions.

Non-innocent ligand behavior of a bimetallic Ni Schiff-base complex containing a bridging catecholate.

The geometric and electronic structure of a bimetallic Ni Schiff-base complex and its one-electron oxidized form have been investigated in the solid state and in solution. The two salen units in the neutral complex 1 are linked via a bridging catecholate function. The one-electron oxidized form [1](+) was determined to exist as a ligand radical species in solution, with the electron hole potentially localized on the redox-active dioxolene, the phenolate ligands, or delocalized over the entire ligand system.

Phthalocyanine as a chemically inert, redox-active ligand: structural and electronic properties of a Nb(IV)-oxo complex incorporating a highly reduced phthalocyanine(4-) anion.

This report describes the reduction of a niobium(V) phthalocyanine complex and investigation of the electronic structure of the resulting products. The reduction of PcNbCl(3) (Pc = phthalocyanine dianion) with 5.5 equiv of potassium graphite in 1,2-dimethoxyethane (DME) resulted in the isolation of K(2)PcNbO.