Synthesis of lithium corrole and its use as a reagent for the preparation of cyclopentadienyl zirconium and titanium corrole complexes.

The lithium corrole complex (Mes(2)(p-OMePh)corrole)Li(3)·6THF (1·6THF), prepared via deprotonation of the free-base corrole with lithium amide, acts as precursor for the preparation of cyclopentadienyl zirconium(iv) corrole (2) and pentamethylcyclopentadienyl titanium(IV) corrole (3).

Substitution and reaction chemistry of cobalt complexes supported by [N2P2] ligands.

The coordination chemistry of mono- and divalent cobalt complexes supported by the monoanionic multidentate ligands, [N(2)P(2)] (where [N(2)P(2)] = (t)BuN((-))SiMe(2)N(CH(2)CH(2)P(i)Pr(2))(2)) and [N(2)P(2)(tolyl)] (where [N(2)P(2)(tolyl)] = MeC(6)H(4)N((-))SiMe(2)(CH(2)CH(2)P(i)Pr(2))(2)), is presented. The Co(II) halide complex [N(2)P(2)]CoI (2) serves as a precursor to the alkyl, hydride, and amide species [N(2)P(2)]CoMe (3), [N(2)P(2)]CoCH(2)SiMe(3) (4), [N(2)P(2)]CoH (5), [N(2)P(2)]CoNHPh (10), and [N(2)P(2)]CoNHC(6)H(4)Me (11). Reduction of 2 results in the formation of a stable, monomeric Co(I) species, [N(2)P(2)]Co (6). Compound 6 can be trapped with CO to form either [N(2)P(2)]Co(CO) (7) or [(t)BuN(C=O)SiMe(2)N(CH(2)CH(2)P(i)Pr(2))(2)]Co(CO)(2) (8) depending on the number of equivalents of CO introduced. Compound 6 also serves as a precursor to transient Co(III) imido species. The Co(II) halide complex [N(2)P(2)(tolyl)]CoI (16) is synthesized through an analogues reaction to that of 2. Reduction of 16 results in the formation of [N(2)P(2)(tolyl)]Co (17), and differences in the coordination and reaction chemistry of 6 and 17 are described.

Synthesis and characterization of manganese and iron complexes supported by multidentate [N2P2] ligands.

The coordination chemistry of mono- and divalent manganese and iron complexes supported by the monoanionic multidentate ligands, [N2P2] (where [N2P2] = tBuN(-)SiMe2N(CH2CH2PiPr2)2) and [N2P2tolyl] (where [N2P2 tolyl] = MeC6H4N(-)SiMe2(CH2CH2PiPr2)2) is presented. The Mn(II) and Fe(II) halide complexes [N2P2]MnCl (1) and [N2P2]FeCl (2) serve as precursors to the alkyl and hydride species [N2P2]MnMe (3), [N2P2]FeMe (4), [N2P2]FeCH2SiMe3 (5), and ([N2P2]Mn)2(mu-H)2 (6). Reduction of 1 and 2 results in the formation of the new bridging dinitrogen complexes ([N2P2]Mn)2(mu-N2) (7) and ([N2P2]Fe)2(mu-N2) (8), respectively. Upon exposure to vacuum, N2 is abstracted from 8, resulting in the observed Fe(I) complex, [N2P2]Fe (9). The new Fe(II) halide complex [N2P2tolyl]FeCl (10) was isolated following the substitution of [N2P2tolyl] for [N2P2]. Reduction of 10 in the presence of N2 resulted in the formation of the dinitrogen free adduct [N2P2tolyl]Fe (11).

Use of tetradentate monoanionic ligands for stabilizing reactive metal complexes.

Ligand scaffolding: The chemist's ability to choose from a wide range of supporting ligands is an important factor in designing new metal complexes. The introduction of new ligand scaffolds with different donor types and coordination numbers allows for the expansion of reaction chemistry at metal centers. This article surveys the use of the tetradentate monoanionic (TMDA) ligands (shown here) with main-group, transition-metal, and f-block elements. Supporting ligand design has played a vital role in the development of coordination and organometallic chemistry. A myriad of ligands with varying charge, donor-type, and denticity have been explored in this realm. A ligand type that has garnered recent attention involves a tetradentate monoanionic (TDMA) framework. TDMA ligands have been used with p-, d-, and f-block elements to form an array of interesting new complexes with applications ranging from bioinorganic chemistry to catalysis. Complexes incorporating TDMA ligands have been shown to stabilize reactive low-valent and cationic species. Functionalized beta-diiminato and TACN derivatives as well as tripodal ligands featuring both hard sigma-donors as well as "mixed-donors" are covered in this review. The synthetic challenges associated with the implementation of each ligand set are discussed.

Reactivity of a Co(I) [N(2)P(2)] complex with azides: evidence for a transient Co(III) imido species.

The synthesis of a monomeric Co(i) complex supported by a multidentate monoanionic [N(2)P(2)] ligand is described; interaction with aryl azides at low temperature generates a species whose reactivity is consistent with imido ("Co[double bond, length as m-dash]NR") character.

First-row transition metal-halide complexes supported by a monoanionic [N(2)P(2)] ligand.

Metal-halide complexes of a multidentate monoanionic ligand tBuN(H)SiMe2N(CH2CH2PiPr2)2, H[N2P2], with Ti, V, Cr, Mn, Fe, Co, and Ni have been isolated and characterized. X-ray crystallographic studies were performed on [N2P2]TiCl2 (3), [N2P2]CrCl2 (5), [N2P2]MnCl (6), [N2P2]FeCl (7), [N2P2]CoCl (8), and [N2P2]NiBr (9), and the results revealed that the [N2P2] ligand exhibits considerable flexibility in the manner in which it binds to first-row metals and that three distinct coordination modes are observed: kappa3-N2P (Ti), kappa3-NP2 (Mn, Fe, Co), and kappa4-N2P2 (Cr, Ni). Electrochemical (CV) data and room-temperature magnetic susceptibilities are also described.

Transition metal dinitrogen complexes supported by a versatile monoanionic [N2P2] ligand.

By adjusting to the steric and electronic requirements of differing metal centers, the new multidentate monoanionic ligand [N(2)P(2)] has demonstrated a unique ability to stabilize a range of transition metal-dinitrogen complexes in a variety of oxidation states and coordination geometries.

Synthesis and reactivity of metal complexes supported by the tetradentate monoanionic ligand bis(2-picolyl)(2-hydroxy-3,5-di-tert-butylbenzyl)amide (BPPA).

Metal-halide complexes of Ti, V, Y, Zr, Al, Ga, and U supported by the tetradentate monoanionic (TDMA) ligand bis(2-picolyl)(2-hydroxy-3,5-di-tert-butylbenzyl)amine, H(BPPA), were synthesized and spectroscopically characterized. In addition, the complexes (BPPA)TiCl2, (BPPA)VBr2, [(BPPA)YCl2]2, (BPPA)AlCl2, (BPPA)GaCl2, and (BPPA)UI3 were characterized by single-crystal X-ray crystallography. In all cases the ligand is bound kappa4 to the metal center. All structurally characterized compounds are monomeric in the solid-state with the exception of [(BPPA)YCl2]2, which exists as a dimer in the solid-state. The metal-alkyl complexes (BPPA)AlMe2 and (BPPA)Zr(CH2Ph)3 were also synthesized and characterized, and an X-ray structure of (BPPA)Zr(CH2Ph)3 was obtained. The transformation of BPPA from a monoanionic to a dianionic ligand via proton abstraction was observed and monitored by NMR spectroscopy.