A family of dioxo-molybdenum(VI) complexes of N2X heteroscorpionate ligands of relevance to molybdoenzymes.

Four new Mo(VI)-dioxo complexes of a family of N2X heteroscorpionate ligands are reported which, together with data already available for (TpR)-, provide a unique example of a comprehensive set of isostructural, isoelectronic complexes differing only in one biologically relevant donor atom. A study of these complexes allows for a direct comparison of structural, spectroscopic, and oxygen atom transfer reactivity properties of the Mo(VI)-dioxo center (of relevance to various families of molybdoenzymes) as a function of donor atom identity.

Donor atom dependent geometric isomers in mononuclear oxo-molybdenum(V) complexes: implications for coordinated endogenous ligation in molybdoenzymes.

We have previously demonstrated that the complex [(L1O)MoOCl(2)], where L1OH = (2-hydroxy-3-tert-butyl-5-methylphenyl)bis(3,5-dimethylpyrazolyl)methane, exists as both cis and trans isomers (Kail, B.; Nemykin, V. N.

Modulating the reduction potential of mononuclear cobalt(II) complexes via selective deprotonation of tris[(2-benzimidazolyl)methyl]amine.

Remote site deprotonation of the coordinated tripodal ligand, tris((2-benzimidazolyl)methyl)amine, was examined using electronic spectroscopy and electrochemistry techniques. The solid-state structures [CoH(3)1(tba)(NCS)]+ and [CoH(2)1(tba)(NCS)] are reported. These complexes crystallized in the triclinic space group P1 [a = 13.

Synthesis and Characterization of Pseudotetrahedral N(2)O and N(2)S Zinc(II) Complexes of Two Heteroscorpionate Ligands: Models for the Binding Sites of Several Zinc Metalloproteins.

Nine new pseudotetrahedral Zn(II) complexes of the heteroscorpionate ligands (3-tert-butyl-2-hydroxy(or thio)-5-methylphenyl)bis(3,5-dimethylpyrazolyl)methane, L1OH or L2SH, have been prepared and characterized (in most cases crystallographically). Complexes isolated include [(L1O)ZnCl], [(L1O)ZnI], [(L1OH)ZnI(2)], [(L1O)ZnCH(3)], [(L1O)ZnOAc], [(L1O)ZnSPh], [(L1O)ZnSBz], [(L2S)ZnCH(3)], [(L2S)ZnSPh], and [(L2S)(2)Zn]. In conjunction with the widely studied tris(pyrazolyl)borates this new series of heteroscorpionates provides a set of isolobal and isoelectronic ligands differing in donor set, i.

The Synthesis and Characterization of 4, 5, and 6 Coordinate Ni(II) Complexes of the "Heteroscorpionate" Ligand (3-tert-Butyl-2-hydroxy-5-methylphenyl)bis(3,5-dimethylpyrazolyl)methane.

Six new Ni(II) complexes of the "heteroscorpionate" ligand (3-tert-butyl-2-hydroxy-5-methylphenyl)bis(3,5-dimethylpyrazolyl)methane, L1OH, have been prepared and characterized (in most cases crystallographically). These complexes include: tetracoordinate [Ni(L1O)Cl]; pentacoordinate [Ni(L1O)(acac)] and [Ni(L1O)(OAc)]; and hexacoordinate [Ni(L1O)(acac)(pz)], [Ni(L1O)(OAc)(MeOH)], and [Ni(L1O)(2)]. This second generation of heteroscorpionate ligand supports a tetrahedral environment for Ni(II) but is not a tetrahedral enforcer.

Hydrogen-Bonding Cavities about Metal Ions: Synthesis, Structure, and Physical Properties for a Series of Monomeric M-OH Complexes Derived from Water.

The tripodal ligand N[CHCHNHC(O)NHC(CH)] ([H 1]) was used to synthesize a series of monomeric complexes with terminal hydroxo ligands. The complexes [CoH 1(OH)], [FeH 1(OH)] , and [ZnH 1(OH)] have been isolated and characterized. The source of the hydroxo ligand in these complexes is water, which was confirmed with an isotopic labeling study for [CoH 1(OH)].

Hydrogen-Bonding Cavities about Metal Ions: A Redox Pair of Coordinatively Unsaturated Paramagnetic Co-OH Complexes.

Nature uses hydrogen bonds to regulate a variety of metal-based reactions. These effects are emulated in the stabilization of trigonal-bipyramidal, paramagnetic Co-OH complexes such as the mono- or dianionic redox-active complex 1 by use of a new hydrogen-bonding ligand.