Girolamo La Monica

Oxidation reaction of [{Cu(Hpz)2Cl}2](Hpz = pyrazole): synthesis of the trinuclear copper(II) hydroxo complexes [Cu3(OH)(pz)3(Hpz)2Cl2]·solv (solv = H2O or tetrahydrofuran). Formation, magnetic properties, and X-ray crystal structure of [Cu3(OH)(pz)3(py)2Cl2]·py (py = pyridine)

The trinuclear copper(II) complexes [Cu3(OH)(pz)3(Hpz)2Cl2]·solv (Hpz = pyrazole, pz = pyrazolate anion, solv = H2O or tetrahydrofuran) have been obtained by oxidation reactions of [{Cu(Hpz)2Cl}2]. When treated with pyridine(py), both CuII derivatives gave the related compound [Cu3(OH)(pz)3-(py)2Cl2]·py, which has been characterized by a single-crystal X-ray structure analysis. Crystals are orthorhombic, space group Pnma(no. 62), a= 19.883(3), b= 15.063(3), c= 9.495(2)A, Z= 4, R= 0.035 and R′= 0.041 for 1 472 absorption corrected reflections having I > 3σ(I).

The bis(salicylaldehyde)ethylenediimine cobalt(II)-catalysed oxidative carbonylation of primary and secondary amines

Abstract Anilines are oxidized to azobenzenes in methanol or methylene chloride solution using dioxygen as the oxidant and bis(salicylaldehyde)ethylenediimine cobalt(II) (CoIIsalen) as catalyst. In the presence of carbon monoxide, isocyanates, urethanes and ureas are also obtained. The latter two are the only reaction products when the aliphatic amine 1-adamantylamine is used as a substrate. Increasing the pressures of dioxygen and carbon monoxide significantly improves reaction yields. Ortho-aminophenol give the corresponding azo derivative and an oxazolone. Aromatic secondary amines give secondary formamides in low yields.

Selective Ortho-Hydroxylation of phenols in copper(I) Complexes

Abstract Several catechols are obtained by reacting excess of the corresponding phenols with the tetrahydroborato copper(I) complex ( 4 ) and subsequent dioxygen oxidation of the intermediate copper(I) phenoxo complex ( 1 ).

Reactions of CO2 with tetrahydroborato copper(I) complexes in moist solvents: Synthesis and reactions of [(phen)2Cu] [(HO)3B(O2CH)] and (phen)(Ph3P)Cu(O2COH) (phen = 1,10-phenanthroline)

Carbon dioxide reacts with the tetrahydroborato copper(I) complex, (phen)(Ph3P)Cu(BH4) (phen = 1,10-phenanthroline) (1) in moist tetrahydrofuran and in the presence of free phen affording the ionic derivative [(phen)2Cu] [(HO)3B(O2CH)] (3). The same complex 3 can be obtained from 1 and aqueous formic acid in the presence of phen; from the new tetrahydroborato copper(I) complex, (phen)2Cu(BH4) (2), and aqueous formic acid; and from 2 with CO2 in moist tetrahydrofuran. The reaction of (phen)(Ph3P)Cu(BH4) (1) with CO2 in moist methanol gives the bicarbonato derivative, (phen)(Ph3P)Cu(O2COH) (4). The action of alcohols, ROH, on 3 causes the formation of the ionic formato complex [(phen)2Cu](O2CH) (5), the boron atom being eliminated as the alkyl boric ester, (RO)3B. Complex 3 reacts with an alcoholic triphenylphosphine solution giving the already reported covalent formato derivative, (phen)(Ph3P)Cu(O2CH). The reaction of 3 with PhCH2Br gives the benzyl formic ester HCO2CH2Ph. The reactivity of 4 toward neutral ligands such as phen and CyNC has been investigated, the ionic bicarbonato derivatives, [(phen)2Cu](HCO3) (8) and [(phen)(CyNC)2Cu](HCO3) (9), being obtained respectively.

The chemical behaviour of the azido group bonded to copper(I): Synthesis and reactivity of thiothiatriazolato and alkynyl complexes

The copper(I) azido-derivatives, (PPh3)(phen)CuN3 (Ia) and (PPh3)(TMP)CuN3 (Ib) (phen = 1,10-phenanthroline; TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline), obtained from [(PPh3)2CuN3]2 and the bidentate ligand (biL), react with CS2 to give the thiothiatriazolato-copper(I) complexes, (PPh3)(phen)CuNC(S)SNN (IIa) and (PPh3)(TMP)CuNC(S)SNN (IIb). The preparation of IIa and IIb occurs only when free triphenylphosphine is present in the reaction medium. The isothiocyanate complexes, (PPh3)(biL)Cu(NCS) (biL = phen, IIIa; biL = TMP, IIIb) are formed, instead of IIa and IIb, when free PPh3 is not added to the reaction medium. The complexes IIIa and IIIb are also obtained when CH2Cl2 solutions of IIa and IIb are stirred for 15 h in the absence of light; if longer reaction times are used, the dimeric isothiocyanato complexes [(biL)Cu(NCS)]2 are formed. Compounds IIa and IIb react with PhCOCl to give (PPh3)(biL)CuCl and 4-benzoyl-1,2,3,4-thiatriazole-5-thione, PhCONC(S)SNN. Treatment of Ia and Ib, or [(PPh3)2CuN3]2, with COS did not lead to isolation of characterizable products. An unsaturated molecule such as ethyl propriolate, EtO2CCCH, does not behave as a 1,3-dipolarophile in its reactions with Ia and Ib, the alkynyl derivatives [(biL)Cu2(CCCO2Et)2]n (n is probably 2; biL = phen, IVa; biL = TMP, IVb), being obtained. Similarly the azido-complex [(PPh3)2CuN3]2 reacts with ethyl propiolate to give the asymmetric binuclear alkynyl derivative, (PPh3)3Cu2(CCCO2Et)2 (V). The reaction of V with hydrogen chloride gives EtO2CCCH and the known complex (PPh3)3Cu2Cl2, confirming the above formulation. The reactions of V with neutral ligands such as TMP, phen and CyNC have also been studied, leading to the isolation of new copper(I) alkynyl-derivatives.

The bis(salicylaldehyde) ethylenediimine cobalt (II). Catalysed oxidative carbonylation of 1-adamantylamine in alcohol: a study for optimising carbamate formation

Abstract The oxidative carbonylation of 1-adamantylamine with dioxygen and carbon monoxide in methanol and with bis(salicylaldehyde)ethylenediimine cobalt(II) as catalyst to give the corresponding carbamate and urea is sensitive to the reaction temperature, the [substrate]/[catalyst] ratio and the pressure of the reactants. In the same conditions, diphenylmethane and anthracene exhibit only oxidation to benzophenone and anthraquinone respectively, and the antitumoral drug 3,6-diamino-2,7-dimethylacridine (acridine yellow) gives the corresponding monocarbamate.

The catalytic carbonylation at atmospheric pressure of phenyl azide to PhNCO, PhNHCONHPh and PhNHCOOEt

Abstract The catalytic activities of rhodium(I) complexes in the carbonylation of phenyl azide at atmosphere pressure, leading to the corresponding isocyanate have been studied. [Rd(DPE) 2 ] Cl and RhCl(CO)(PPh 3 ) 2 are the most active catalysts, and maintain their high activity even in the presence of aniline (which gives diphenylurea) or ethanol (which gives carbamate).

Pyrazolato Metal Complexes – Synthesis, Characterization, and X-ray Crystal Structures of Heterotrimetallic Re–M2 Derivatives (M = Cu, Ag, Au)

By treating [(CO)3Re(Hpz)2(pz)] (Hpz = pyrazole) with [Cu(CH3CN)4]BF4, AgNO3, or [Au(tht)Cl] (tht = tetrahydrothiophene) in acetonitrile in the presence of Et3N, the corresponding trinuclear complexes {(CO)3Re(pz)3[M(CH3CN)]2} (1a–c) have been obtained. Treatment of complexes 1a–c with cyclohexyl isocyanide (c-C6H11NC) afforded the derivatives {(CO)3Re(pz)3[M(c-C6H11NC)]2} (2a–c). Complexes 2a–c have been characterized in solution by 1H-NMR spectroscopy and in the solid state by single-crystal X-ray diffraction analysis.

The stepwise interaction of [(phen)(Ph3P)Cu(O2COH)] with pyrazoles and CO2: Synthesis and reactivity of copper(I) pyrazolecarboxylates

Abstract Reactions between [(phen)(Ph 3 P)Cu(O 2 COH)] ( A , phen = 1,10-phenanthroline) and 3,5-dimethyl- pyrazole (pzH) or pyrazole (PzH) in acetone afford the insoluble copper(I) pyrazolates [Cu(pz)] n or [Cu(Pz)] n and red solutions. The action of CO 2 on these suspensions at low temperature yields new copper(I) pyrazolecarboxylates of formula [(phen)(Ph 3 P)Cu(O 2 Cpz)(H 2 O)] ( 1a ) or [(phen)(Ph 3 P)Cu(O 2 CPz)(H 2 O)] ( 1b ) respectively. When heated at 80 °C under vacuum as solid, 1a gives [(phen)(Ph 3 P)Cu(pz)] ( 2 ). The latter can be also obtained by N 2 bubbling at 0 °C through suspensions of 1a . At higher temperatures the decarboxylation reaction of 1a is accompanied by the loss of phen and PPh 3 , [Cu(pz)] n being recovered as the final product. By stirring an acetone suspension of 1a under a CO 2 atmosphere, free pzH and an orange product analysing as [(phen)(Ph 3 P)Cu(O 2 COH)] ( 3 ) were isolated. Complex 3 , although having the same stoichiometry as A , was shown to exhibit spectroscopic and some chemical properties quite different from those of A . The action of pzH under an inert atmosphere on 3 (molar ratio pzH/ 3 = 1), allowed the isolation of 1a , without carbon dioxide evolution. Excess phen on polymeric [Cu(pz)] n causes the formation of [(phen)Cu(pz)] 2 ( 4 ), probably containing a bridging pyrazolate group. The latter has been reacted with CO 2 in the presence of pzH (molar ratio pzH/ 4 >1) obtaining the pyrazolecarboxylato complex 5 , [(phen)(pzH)Cu(O 2 Cpz)]. The neutral pyrazole ligand present in 5 , weakly bound to the metal center, can be easily displaced by triphenyl- phosphine, with formation of 1a , or by cyclohexyl- isocyanide. In the latter case, displacement of both pzH and phen has been observed, and the new pyrazolyl complex 6 [(CyNC)Cu(pz)] 2 , formed. Gas volumetric and thermogravimetric measurements and IR spectra are reported and discussed. A plausible mechanism by which complexes 1 are formed, is also reported.

Oxidation reaction of the copper(I) phenoxo complex [(phen)(Ph3P)Cu(OPH)]: The formation of the copper(II) derivative [(phen)Cu(OPh(OC6H4-2-(OH)], having a catecholate group derived from phenol hydroxylation reaction

The copper(I) bicarbonato complex [(phen)(Ph3P)Cu(O2COH)] (1) (phen = 1,10-phenanthroline) reacts under nitrogen with phenol giving the copper(I) phenoxo derivative [(phen)(Ph3P)Cu(OPh)] (2). Complex 2 was shown to undergo a facile hydrolysis, PhOH being released. The action of moist CO2 on 2 allowed the isolation of the starting bicarbonato complex 1. The reaction of 1 with excess phenol under an oxygen atmosphere, gave the unexpected copper(II) derivative [(phen)Cu(OPh)(OC6H4-2-(OH)] (3). The catecholate group, OC6H4-2-(OH), which is present in complex 3, originates from a phenol hydroxylation reaction assisted by the copper center. The same complex 3 has been also obtained by reacting 2 with excess PhOH under oxidative conditions. The bicarbonato complex 1 reacts with catechol under an oxygen atmosphere giving [(phen)Cu(cat)] (4) or the bis(catecholate)copper(II) derivative, (phen)Cu[OC6H4-2-(OH)]2 (5), depending on the molar ratio copper/catechol. The copper(II) complexes 3, 4 and 5 were shown to be sensitive to water; in the case of compounds 3 and 5 a reaction takes place, the CuOPh (complex 3) and one of the CuOC6H4-2-(OH) (complex 5) groups being involved, phenol (complex 3) and catechol (complex 5) being respectively released. Complex 4, owing to its tendency to retain water of crystallization, converts into [(phen)Cu(cat)]H2O (6). From the hydrolysis reactions of 3 and 5, Download full-size image the catecholato derivative 6 was always obtained, probably through the intermediate formation of the copper(II) hydroxo-catecholate complex [(phen)Cu(OH)(OC6H4-2-(OH))].