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The actinide and lanthanide bonding in M[N(EP[Ph.sub.2]).sub.2].sub.3]] and M[N(EPi[Pr.sub.2]).sub.2].sub.3]] is structurally studied using spectroscopic methods and density functional theory calculations. The increased covalency in the M-E bond is found due to increased d-orbital participation, while in An-E bonds it is due to f-orbital participation.

A general and versatile Cu-(I)-based oxidation procedure that enables facile access to pentavalent organouranium complexes is described. It gives insight into derivatives electronic structure and bonding and also oxidation states of copper and uranium reagents.

The systematic studies of a series of eight uranium (IV) bis(fluoroketimide) complexes which exhibited the covalency of the uranium(IV) ketimide interaction is reported.

The synthesis of a uranium oxo imido complex, namely, trans-[U(NR)(O).sup.2+], which provides a link between an isostructural uranyl analogue and bis(imido) extremes, is reported. The structural data and theoretical results demonstrate that, like the bis(imido) complexes, the mixed oxo imido species still maintain many of the qualities that uranyl possesses, including significant uranium f and d electron participation in the multiple bonds.

A series of bulky allyl terpyridyl-ytterbium complexes are synthesized to determine the effect of allyl ligands on the internal charge-transfer process that exists in these materials. Compared to the pantamethylcyclopentadienyl-ytterbocene compound Cp*2Yb(tpyCN), the symmetrically substituted allyl complex [1,3-(SiMe3)2C3H3]2Yb(tpyCN) possesses a markedly lowered equivalent to N frequency of 2130 [cm.sup.-1].

The reactivity of the phenyl dichalcogenides (PhE-EPh, E = S, Se, Te) with three metal complexes M[(CO).sub.3][(P[R.sub.3]).sub.2], W(CO)3(PR3)2 and Mo[(N[[t.sub.Bu]]Ar).sub.3] is investigated. The calculations of electron densities of the SOMO have shown the increasing electron density on the chalcogen atom on going from S to Se to Te.

The concomitant alterations in electron-density distributions and spatial extents in the lowermost unoccupied molecular orbital (LUMO) of the N-heterocyclic ligand as compared to monometallic complexes and the effect of increased metal-metal separation on the mechanism and/or magnitude of the electronic/magnetic coupling are determined. The optical spectroscopic results for ytterbocene complexes have shown that the spectra are dominated by the one- or two-electron reduced polypyridyl ligands.

Two americium(III) iodates, beta-Am(IO3)3 and alpha-Am(IO3)3 are prepared from the aqueous reactions of Am(superIII) with KlO4 at 180 degrees Celsius and are characterized by single-crystal X-ray diffraction, diffuse reflectance and Raman spectroscopy. The alpha-form, consistent with the known structure of anhydrous lanthanide iodates, is a 3D network of pyramidal iodate groups, while the beta-form has a 2D layered structure with nine-coordinate Am(super III) atoms, novel to the f-element iodate series.

A new series of Fe(II), FeCl2{N(R)=C(Me)=N(R)} containing diimine ligands with hemiliable sidearms R (R=CH2(CH2)2NMe(sub 2), CH2(CH2)2OMe, CH2(CH2)2SMe) were synthesized. It was found that interaction of Co with high-spin 5-coordinate Fe model complex is thermoneutral but favored to low-spin diphosphine fragments.

Characterization of products from the oxidation of uranium metal with 1.3 equiv of iodine in nitrile solvents is described, while this reaction is carried out in acetonitrile, isolated the [U(N=CMe)(sub 9)][UI(sub 6)][I]. The same reaction carried out in benzonitrile provides UI(sub 4)(N=CPh)(sub 4) as the only product.

A new 4'-cyanoterpyridyl adduct of ytterbocene is prepared that displays physical properties similar to those seen in other di- and triimine complexes of ytterbocene. The differing coordination modes for the 4'-cyano-2,2':6',2''-terpyridine (tpyCN) ligand to the ytterbocene center is confirmed by isolation and X-ray crystallographic characterization of complexes binding through either the cyano nitrogen of tpyCN or the three terpyridyl nitrogen atoms of tpyCN.

The synthesis and structural characterization of mixed Pu(VI) hydroxo-iodate compound, (PuO2)2(IO3)(OH)3 is presented. The structure consists of two-dimensional layers forming in the ac plane and is the first single-crystal structure of plutonium(VI) connected through hydroxide anions.

A study on the synthesis and solution behavior of La2(NHAr)6 (Ar = 2,6-(super i)Pr2C6H3) and its complexation with the Lewis bases is conducted. A comparison of the observed chemistry of this arylamide system with the structurally related aryloxide is presented.

The formation of ionic species like [LuI2(HOPr)4][I], is discussed. It forms when lutetium metal reacts with elemental iodine in 2-propanol.

To prepare a variety of novel cyclotriphosphazene-based ligand systems with N and O donor sets, a straightforward solvent-free methodology is developed. With selected ligand constructs, a variety of metal complexes are synthesized.

Research has been conducted on tris(bis(trimethylsilyl)amido)samarium. The study of this compound has been carried out via the use of density functional theory and X-ray crystallography, and the results have demonstrated that the structure features positional disorder of the metal atom above and below the plane defined by three N donor atoms.

Research has been conducted on neptunyl(VI) iodates. The authors describe the preparation of these compounds in HCl via aqueous reactions of Np(V) with KIO (sub)4, and their characterization via single-crystal X-ray diffraction and Raman spectroscopy.

We report the small‐scale synthesis, isolated yield, single‐crystal X‐ray structure, 1H NMR solution spectroscopy /solid‐state UV/Vis‐nIR spectroscopy, and density functional theory (DFT)/ab initio wave function theory calculations on an Am3+ organometallic complex, [Am(C5Me4H)3] (1). This constitutes the first quantitative data on Am−C bonding in a molecular species. [ABSTRACT FROM AUTHOR]

This work provides new routes for the conversion of U(iv) into U(vi) bis(imido) complexes and offers new information on the manner in which the U(vi) compounds form. Many compounds from the series described by the general formula U(NR)2(EPh)2(L)2 (R = 2,6-diisopropylphenyl, tert-butyl; E = S, Se, Te; L = py, EPh) were synthesized via oxidation of an in situ generated U(iv) amido–imido species with Ph2E2. This synthetic sequence provides a general route into bis(imido) U(vi) chalcogenolate complexes, circumventing the need to perform problematic salt metathesis reactions on U(vi) iodides. Investigation into the speciation of the U(iv) complexes that form prior to oxidation found a significant dependence on the identity of the ancillary ligands, with tBu2bpy forming the isolable imido–(bis)amido complex, U(NDipp)(NHDipp)2(tBu2bpy)2. Together, these data are consistent with the view that the bis(imido) U(vi) motif – much like the uranyl ion, UO22+– is a thermodynamic sink into which simple ligand frameworks are unable to prevent uranium from falling when in the presence of a suitable retinue of imido proligands. [ABSTRACT FROM AUTHOR]

Three new uranium species (C5Me5)2U(=N-2,6-iPr2-C6H3)(=S), (C5Me5)2U(=N-2,6-iPr2-C6H3)(η2-S2), and (C5Me5)2U(=N-2,6-iPr2-C6H3)(S=PMe3) were synthesized and fully characterized by a combination of NMR, IR, and UV/vis–NIR spectroscopies, elemental analysis, and cyclic voltammetry. The solid state structures of (C5Me5)2U(=N-2,6-iPr2-C6H3)(=S) and (C5Me5)2U(=N-2,6-iPr2-C6H3)(η2-S2) were also determined. The compound (C5Me5)2U(=N-2,6-iPr2-C6H3)(=S) is the first neutral uranium complex with a terminal sulphido ligand, and (C5Me5)2U(=N-2,6-iPr2-C6H3)(S=PMe3) is the first uranium compound with a coordinated phosphine sulphide ligand. The phosphine sulphide adduct, (C5Me5)2U(=N-2,6-iPr2-C6H3)(S=PMe3), can be synthesized either by reaction of the uranium(iv) complex (C5Me5)2U(=N-2,6-iPr2-C6H3)(thf) with S=PMe3 or by the reaction of the uranium(vi) terminal sulphido complex (C5Me5)2U(=N-2,6-iPr2-C6H3)(=S) with PMe3. [ABSTRACT FROM AUTHOR]

The synthesis and structural characterization of a rare example of a uranyl complex possessing three equatorial ligands [M(THF)2][UO2(N(SiMe3)(sub 2))(sub 3)] are described. The series of uranyl amido complexes [UO2(N(SiMe3)(sub 2))(sub n)](super 2-n) (n=2-4) provides a unique opportunity to examine the effects of increasing electron donation by equatorial ligands on the bond strength of axial U=O bonds.

The synthesis and a single-crystal X-ray diffraction study of a member of a new structural class of lanthanide tetracarbonate complexes, [Co(NH3)(sub 6)](sub 6-)[K(sub 2)(H2))(sub 10)][Nd(sub 2)(CO3)(sub 8)](sub 2) are reported. The role, that factors such as ionic radius play in determining the generality of the structure seen in the complex are discussed.