6.1.2. Aqueous V(III) Chemistry 877 6.1.3. Oxidation State of Vanadium in Tunicates 878 6.1.4. Uptake of Vanadate into Tunicates 879 6.1.5. Vanadium Binding Proteins: Vanabins 879 6.1.6. Model Complexes and Their Chemistry 880 6.1.7. Catechol-Based Model Chemistry 880 6.1.8. Vanadium Sulfate Complexes 881 6.2. Fan Worm Pseudopotamilla occelata 883 7. Vanadium Nitrogenase 883 7.1. Nitrogenases 883 7.2. Biochemistry of Nitrogenase 884 7.3. Clusters in Nitrogenase and Model Systems: Structure and Reactivity 885

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The chemistry and biochemistry of vanadium and the biological activities exerted by vanadium compounds.

Light-Emitting Self-Assembled Materials Based on d(8) and d(10) Transition Metal Complexes.

N atom, thus providing carbenes derived from pyrazolium, isothiazolium, and even quinolinium salts that contain a stabilizing heteroatom in a remote position (G-J in Figure 1). Recently, carbenes such as K, which are comprised of only one heteroatom and lack delocalization through the heterocycle, have been discovered as versatile ligands, thus constituting another important class of carbenes with low heteroatom stabilization. Both the synthesis of the organometallic complexes of these ligands as well as the (catalytic) properties of the coordinated metal centers generally show distinct differences, compared to the more classical NHC complexes, such as C2-metallated imidazolylidenes. This review intends to describe such differences and highlights the chemical peculiarities of these types of N-heterocyclic carbene complexes. It introduces, in a qualitative manner, the synthetic routes that have been established for the preparation of such complexes, covering the literature from the very beginning of activities in this area up to 2008. While specialized reviews on some aspects of the present topic have recently appeared,7 a comprehensive overview of the subject has not been available thus far. Rather than just being descriptive, the present account is mainly directed toward the impact of these still unusual metal-carbene bonding modes on the electronic properties and on the new catalytic applications that have been realized by employing such new carbene complexes. As a consequence of our focus on complexes with less-stabilized heterocyclic ligands, systems comprising acyclic carbenes have not been included, and the interested reader is, instead, referred to the pioneering and

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Beyond Conventional N-Heterocyclic Carbenes: Abnormal, Remote, and Other Classes of NHC Ligands with Reduced Heteroatom Stabilization

Molybdenum(VI) speciation in sulfidic waters; stability and lability of thiomolybdates

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Vapochromism in organometallic and coordination complexes: chemical sensors for volatile organic compounds.

https://isabelcorreia.weebly.com/uploads/1/1/1/2/11123979/1_ica_1999.pdf

Preparation and characterisation of new oxovanadium(iv) schiff base complexes derived from amino acids and aromatic o-hydroxyaldehydes

The dinuclear vanadium(v) complex [V2O3(sal-L-val)2(H2O)]1(sal-L-val =N-salicylidene-L-valinate) has been prepared and characterized and its crystal structure determined. The compound contains a double bridge by O (oxo) and O (carboxylate) and is one of the rare examples where the two VO groups make an angle near 90°. There are two independent molecules, A and B, in the asymmetric unit which are similar and each consists of two VO(sal-L-val) groups at nearly right angles to each other. They exhibit a distorted-octahedral geometry, involving in the equatorial plane the O,N,O atoms of the Schiff-base ligand and the bridging O (oxo) group and in the axial positions a carboxyl oxygen of the second VO(sal-L-val) group and a water molecule. The bridging V–O(oxo) bond lengths range between 1.787 and 1.823 A, and are significantly shorter than the bridging V–O(carboxylate), ranging between ≈1.93–1.94 A for equatorial and ≈2.40–2.43 A for axial. Several known [VO(sal-L-aa)(H2O)] and new [VO(sal-L-aa)(bipy)](sal-L-aa =N-salicylidene-L-amino acidate, bipy = 2,2′-bipyridine) complexes were also prepared and their spectroscopic (ESR, UV and CD) properties studied. A correlation observed between the CD intensities and the size of the amino acid side groups is discussed.

Crystal and molecular structure of [V2O3(sal-L-val)2(H2O)](sal-L-val =N-salicylidene-L-valinate) and spectroscopic properties of related complexes

The structure and spectroscopic properties of the red form of [Pt(bipy)Cl2](bipy = 2,2′-bipyridyl) are discussed. Some novel cases of dimorphism are reported. Preparation of the new complexes [Pt(LL)Cl2](LL = 6,6′-Me2-bipy, 5,5′-Me2bipy, 4,4′-Me2bipy), [Pt(LL)2]2+(LL = 5,5′-Me2bipy, 4,4′-Me2bipy), [Pt(bipy)(py)2]2+, [Pt(bipy)-(NO3)(OH)], and [Pt(bipy)(H2O)(OH)]+(py = pyridine) are described and 1H n.m.r. assignments of [Pt(bipy)-(OH)2] and [Pt(bipy)2]2+ have been made by comparison with the corresponding methyl-substituted 2,2′-bipyridyl derivatives. At pH ca. 6, the 220 MHz 1H m.r. spectrum of [Pt(bipy)2]2+ is consistent with a square planar or tetrahedrally distorted structure.

Spectroscopic studies on some compounds (including dimorphic solids) of platinum(II) with 2,2′-bipyridyl and its analogues

2p electron binding energies for the sulfur atoms in metal polysulfides

Solvent effects on the electronic spectra of the complexes [Pt(bipy)X2](bipy = 2,2′-bipyridyl; X = Cl, Br, or I), [Pd(bipy)Cl2], and [Pt(bipy)(py)2]2+(py = pyridine) are reported and correlated with the ET parameters of the solvents. The assignments of the electronic spectra are discussed.

Robert D. Gillard

Papers

Preparation and characterisation of new oxovanadium(iv) schiff base complexes derived from amino acids and aromatic o-hydroxyaldehydes

Crystal and molecular structure of [V2O3(sal-L-val)2(H2O)](sal-L-val =N-salicylidene-L-valinate) and spectroscopic properties of related complexes

Spectroscopic studies on some compounds (including dimorphic solids) of platinum(II) with 2,2′-bipyridyl and its analogues

2p electron binding energies for the sulfur atoms in metal polysulfides

Solvent effects on the electronic spectra of some 2,2′-bipyridyl palladium(II) and platinum(II) complexes