Robert W. McGaff

Efficient catalytic cycloalkane oxidation employing a “helmet” phthalocyaninato iron(III) complex

We have examined the catalytic activity of an iron(III) complex bearing the 14,28-[1,3-diiminoisoindolinato]phthalocyaninato (diiPc) ligand in oxidation reactions with three substrates (cyclohexane, cyclooctane, and indan). This modified metallophthalocyaninato complex serves as an efficient and selective catalyst for the oxidation of cyclohexane and cyclooctane, and to a far lesser extent indan. In the oxidations of cyclohexane and cyclooctane, in which hydrogen peroxide is employed as the oxidant under inert atmosphere, we have observed turnover numbers of 100.9 and 122.2 for cyclohexanol and cyclooctanol, respectively. The catalyst shows strong selectivity for alcohol (vs. ketone) formation, with alcohol to ketone (A/K) ratios of 6.7 and 21.0 for the cyclohexane and cyclooctane oxidations, respectively. Overall yields (alcohol + ketone) were 73% for cyclohexane and 92% for cyclooctane, based upon the total hydrogen peroxide added. In the catalytic oxidation of indan under similar conditions, the TON for 1-indanol was 10.1, with a yield of 12% based upon hydrogen peroxide. No 1-indanone was observed in the product mixture.

Synthesis and crystal structures of five new rhenium acetamidate complexes

Abstract Syntheses are reported of five rhenium(III) cluster complexes with acetamidate ligands: [(C 4 H 9 ) 4 N] 2 [{Re 2 Cl 6 (μ-1,2-NHCOCH 3 )} 2 ] ( 1 ), [(C 2 H 5 ) 4 N][Re 3 Cl 8 (μ-1,2-NHCOCH 3 )(μ-2,3-NHCOCH 3 )]·2.5(C 4 H 10 O) ( 2 ), [(C 4 H 9 ) 4 N] 2 [Re 3 Cl 10 (μ-1,2-NHCOCH 3 )] ( 3 ), [(C 4 H 9 ) 4 N] 2 [{Re 3 Cl 8 (μ-1,2-NHCOCH 3 )(OH)} 2 ]·1.7(C 4 H 10 O) ( 4 ), and (C 4 H 9 ) 4 N[Re 3 Cl 9 (H 2 O)(μ-1,2-NHCOCH 3 )]·C 3 H 6 O ( 5 ). The acetamidate ligands in these complexes arise via reactions of acetonitrile–rhenium halide species (either dirhenium or trirhenium chloride clusters) and water. Coordination activates the nitrile to hydrolysis; proton loss and chelation of the acetamidate ligand with displacement of chloride ion leads to the products. Initial formation of a rhenium(III) acetonitrile complex can be assisted using a halide acceptor, Ag + , to generate an open coordination site on the metal. The reaction with K 4 Mo 2 Cl 8 and Ag + ion in acetonitrile gives Mo 2 Cl 4 (NCCH 3 ) 4 ( 6 ). The use of MALDI mass spectrometry in support of synthetic efforts and as a characterization tool is described, and the molecular structures of 1 – 6 were established using X-ray crystallography.

A tetranuclear dianion consisting of linked dirhenate units arranged in an infinite one-dimensional chain through ligand–ligand hydrogen bonding in the solid state

Abstract The reaction of 1,4-dicyanobenzene with tetrabutylammonium octachlorodirhenate in refluxing ethanol, in the presence of excess water, produces a tetrarhenate dianion in which ligand hydrolysis results in a unique structure. In this structure, two dirhenium units are linked by a benzene-1,4-dicarboxamidate ligand. The product has been characterized by X-ray crystallography and spectroscopic means. In the crystallographically-determined structure, the tetrarhenate dianions are joined by hydrogen bonding into an infinite one-dimensional chain with a ‘zigzag’ motif.

Racemic iron(III) and cobalt(III) complexes containing a new pentadentate “helmet” phthalocyaninato ligand

Solvothermal reactions of iron(II) acetate tetrahydrate and cobalt(II) acetate tetrahydrate with 1,2-dicyanobenzene in methanol solution result in the formation of racemic six-coordinate iron(III) and cobalt(III) complexes, respectively, with a new bicyclic pentadentate 14,28-[1,3-diiminoisoindolinato]phthalocyaninato ligand.

Copper(II) methoxide: Direct solventothermal synthesis and X-ray crystal structure

Copper methoxide has been prepared under fairly mild solventothermal conditions by direct reaction of copper(II) acetate monohydrate and methanol. The product has been structurally characterized for the first time by single crystal X-ray diffraction and found to possess a novel infinite one-dimensional chain structure in which copper atoms in distorted square planar coordination environments are linked by bridging methoxide ligands. The conversion of copper acetate to copper methoxide is essentially quantitative. The major byproduct of the synthesis is methyl acetate.

Constructor graph description of hydrogen bonding in a supra­molecular assembly of N,N′-bis­(2-hydr­oxy-1-methyl­ethyl)phthalamide

Hydrogen bonds of four types (N-H...O=C, N-H...OH, O-H...O=C and O-H...OH) connect molecules of the title compound, C(14)H(20)N(2)O(4), in the crystal into sheets folded into a zigzag pattern. The intermolecular interactions are discussed in terms of the first- through fourth-level graph sets, and a constructor graph helps visualize the supramolecular assembly.

Solventothermal synthesis and X-ray crystal structures of two nickel complexes with novel alkoxy-substituted phthalocyanine ligands

Solventothermal reactions of nickel acetate tetrahydrate with 1,2-dicyanobenzene in methanol and ethanol yield novel complexes in which nickel atoms are coordinated by modified phthalocyanine ligands with inner rings bearing methoxy and ethoxy substituents, respectively.