Hydrogen Peroxide: A Poor Ligand to Gallium Tetraphenylporphyrin

As models for possible heme-iron-H2O2 enzymatic intermediates, tetraphenylporphyrin (TPP)-gallium chemistry has been explored in CD2Cl2. (TPP)GaOTf (1) and (TPP)Ga(ClO4) (2) have been prepared from (TPP)GaCl and AgOTf or AgClO4. Trace water reacts with 2 to give [(TPP)Ga(OH2)](ClO4) (5) and with (TPP)GaOOtBu to give (TPP)GaOH (3). These complexes were fully characterized including X-ray structures for 1, 3, the bis(aquo) analogue of 5, and the methyl derivative (TPP)GaMe (4). A convenient procedure for preparing anhydrous dilute solutions of H2O2 in methylene chloride is described. All of these gallium complexes, however, are unreactive with this anhydrous H2O2 in CD2Cl2. H2O2 does not displace even the weakly coordinating perchlorate or triflate anions, or coordinated water, indicating that H2O2 is a very weak ligand

Hydrogen Peroxide: A Poor Ligand to Gallium Tetraphenylporphyrin

As models for possible heme-iron-H2O2 enzymatic intermediates, tetraphenylporphyrin (TPP)-gallium chemistry has been explored in CD2Cl2. (TPP)GaOTf (1) and (TPP)Ga(ClO4) (2) have been prepared from (TPP)GaCl and AgOTf or AgClO4. Trace water reacts with 2 to give [(TPP)Ga(OH2)](ClO4) (5) and with (TPP)GaOOtBu to give (TPP)GaOH (3). These complexes were fully characterized including X-ray structures for 1, 3, the bis(aquo) analogue of 5, and the methyl derivative (TPP)GaMe (4). A convenient procedure for preparing anhydrous dilute solutions of H2O2 in methylene chloride is described. All of these gallium complexes, however, are unreactive with this anhydrous H2O2 in CD2Cl2. H2O2 does not displace even the weakly coordinating perchlorate or triflate anions, or coordinated water, indicating that H2O2 is a very weak ligand

Hydrogen Peroxide: A Poor Ligand to Gallium Tetraphenylporphyrin

As models for possible heme-iron-H2O2 enzymatic intermediates, tetraphenylporphyrin (TPP)-gallium chemistry has been explored in CD2Cl2. (TPP)GaOTf (1) and (TPP)Ga(ClO4) (2) have been prepared from (TPP)GaCl and AgOTf or AgClO4. Trace water reacts with 2 to give [(TPP)Ga(OH2)](ClO4) (5) and with (TPP)GaOOtBu to give (TPP)GaOH (3). These complexes were fully characterized including X-ray structures for 1, 3, the bis(aquo) analogue of 5, and the methyl derivative (TPP)GaMe (4). A convenient procedure for preparing anhydrous dilute solutions of H2O2 in methylene chloride is described. All of these gallium complexes, however, are unreactive with this anhydrous H2O2 in CD2Cl2. H2O2 does not displace even the weakly coordinating perchlorate or triflate anions, or coordinated water, indicating that H2O2 is a very weak ligand

Hydrogen Peroxide: A Poor Ligand to Gallium Tetraphenylporphyrin

As models for possible heme-iron-H2O2 enzymatic intermediates, tetraphenylporphyrin (TPP)-gallium chemistry has been explored in CD2Cl2. (TPP)GaOTf (1) and (TPP)Ga(ClO4) (2) have been prepared from (TPP)GaCl and AgOTf or AgClO4. Trace water reacts with 2 to give [(TPP)Ga(OH2)](ClO4) (5) and with (TPP)GaOOtBu to give (TPP)GaOH (3). These complexes were fully characterized including X-ray structures for 1, 3, the bis(aquo) analogue of 5, and the methyl derivative (TPP)GaMe (4). A convenient procedure for preparing anhydrous dilute solutions of H2O2 in methylene chloride is described. All of these gallium complexes, however, are unreactive with this anhydrous H2O2 in CD2Cl2. H2O2 does not displace even the weakly coordinating perchlorate or triflate anions, or coordinated water, indicating that H2O2 is a very weak ligand

Hydrogen Peroxide: A Poor Ligand to Gallium Tetraphenylporphyrin

As models for possible heme-iron-H2O2 enzymatic intermediates, tetraphenylporphyrin (TPP)-gallium chemistry has been explored in CD2Cl2. (TPP)GaOTf (1) and (TPP)Ga(ClO4) (2) have been prepared from (TPP)GaCl and AgOTf or AgClO4. Trace water reacts with 2 to give [(TPP)Ga(OH2)](ClO4) (5) and with (TPP)GaOOtBu to give (TPP)GaOH (3). These complexes were fully characterized including X-ray structures for 1, 3, the bis(aquo) analogue of 5, and the methyl derivative (TPP)GaMe (4). A convenient procedure for preparing anhydrous dilute solutions of H2O2 in methylene chloride is described. All of these gallium complexes, however, are unreactive with this anhydrous H2O2 in CD2Cl2. H2O2 does not displace even the weakly coordinating perchlorate or triflate anions, or coordinated water, indicating that H2O2 is a very weak ligand

Nitrogen Atom Insertion into Ir−S and C−S Bonds Initiated by Photolysis of Iridium(III)−Azido-Dithiocarbamato Complexes

Photolysis of acetonitrile solutions of Cp*Ir(R2dtc)(N3) [Cp* = η5-C5Me5, R2dtc = S2CNR2; R = Me (1) or Et (1‘)] at temperatures below 0 °C afford five-coordinate complexes Cp*Ir{NSC(NR2)S} (2 or 2‘), where a nitrogen atom has been inserted into one of the Ir−S bonds. In solution, complex 2 thermally convert to the azaethene-1,2-dithiolate complex, Cp*Ir[SNC(NMe2)S] (3), which could be crystallized as the corresponding dimer, {Cp*Ir[μ-SNC(NMe2)S-κ3S:S,S‘]}2 (4). As a result, a nitrogen atom that originated in the azide ligand is transferred into a C−S bond of the dithiocarbamate

Nitrogen Atom Insertion into Ir−S and C−S Bonds Initiated by Photolysis of Iridium(III)−Azido-Dithiocarbamato Complexes

Photolysis of acetonitrile solutions of Cp*Ir(R2dtc)(N3) [Cp* = η5-C5Me5, R2dtc = S2CNR2; R = Me (1) or Et (1‘)] at temperatures below 0 °C afford five-coordinate complexes Cp*Ir{NSC(NR2)S} (2 or 2‘), where a nitrogen atom has been inserted into one of the Ir−S bonds. In solution, complex 2 thermally convert to the azaethene-1,2-dithiolate complex, Cp*Ir[SNC(NMe2)S] (3), which could be crystallized as the corresponding dimer, {Cp*Ir[μ-SNC(NMe2)S-κ3S:S,S‘]}2 (4). As a result, a nitrogen atom that originated in the azide ligand is transferred into a C−S bond of the dithiocarbamate

Nitrogen Atom Insertion into Ir−S and C−S Bonds Initiated by Photolysis of Iridium(III)−Azido-Dithiocarbamato Complexes

Photolysis of acetonitrile solutions of Cp*Ir(R2dtc)(N3) [Cp* = η5-C5Me5, R2dtc = S2CNR2; R = Me (1) or Et (1‘)] at temperatures below 0 °C afford five-coordinate complexes Cp*Ir{NSC(NR2)S} (2 or 2‘), where a nitrogen atom has been inserted into one of the Ir−S bonds. In solution, complex 2 thermally convert to the azaethene-1,2-dithiolate complex, Cp*Ir[SNC(NMe2)S] (3), which could be crystallized as the corresponding dimer, {Cp*Ir[μ-SNC(NMe2)S-κ3S:S,S‘]}2 (4). As a result, a nitrogen atom that originated in the azide ligand is transferred into a C−S bond of the dithiocarbamate

Oxygen−Oxygen Bond Homolysis in a Novel Titanium(IV) Alkylperoxide Complex, Cp₂Ti(OO<i>^t</i>Bu)Cl

Cp2TiCl2 reacts with NaOOtBu to form the new titanium peroxide complex, Cp2Ti(OOtBu)Cl (1), which has been characterized both in solution and in the solid state. This complex is surprisingly unreactive towards olefins and phosphines, as it does not directly transfer an oxygen atom. Instead, decomposition occurs via initial homolysis of the oxygen−oxygen bond, yielding a tert-butoxyl radical. Decomposition of 1 in the presence of phosphines yields either phosphine oxides (e.g., OPPh3) or phosphinites (e.g., tBuOPEt2), products that result from tBuO• + PR3. O−O bond homolysis is surprising because the Ti(IV) center is d0 and cannot be oxidized, where all previous clear examples of homolytic cleavage of metal peroxide complexes are facilitated by oxidation of the metal center

Oxygen−Oxygen Bond Homolysis in a Novel Titanium(IV) Alkylperoxide Complex, Cp₂Ti(OO<i>^t</i>Bu)Cl

Cp2TiCl2 reacts with NaOOtBu to form the new titanium peroxide complex, Cp2Ti(OOtBu)Cl (1), which has been characterized both in solution and in the solid state. This complex is surprisingly unreactive towards olefins and phosphines, as it does not directly transfer an oxygen atom. Instead, decomposition occurs via initial homolysis of the oxygen−oxygen bond, yielding a tert-butoxyl radical. Decomposition of 1 in the presence of phosphines yields either phosphine oxides (e.g., OPPh3) or phosphinites (e.g., tBuOPEt2), products that result from tBuO• + PR3. O−O bond homolysis is surprising because the Ti(IV) center is d0 and cannot be oxidized, where all previous clear examples of homolytic cleavage of metal peroxide complexes are facilitated by oxidation of the metal center