Andrei Drozdov

Synthesis and characterisation of tin(IV) and organotin(IV) derivatives 2-{((2-hydroxyphenyl)imino)methyl}phenol

Abstract From the interaction of 2-{[(2-hydroxyphenyl)imino]methyl}phenol(salopH2) with tin and organotin(IV) acceptors, the derivatives [SnR3(salopH)] (R=Me or Bun), [SnR2(salop)] (R=Me, Bun, But, Vin or Ph), [SnRX(salop)(solvent)] (R=Me, Bun, Ph or X; X=Cl, Br or I; solvent=CH3OH or H2O), [Sn(salop)2], [R2SnCl2(salopH2)] (R=Me or Bun) have been obtained and characterised. The chelates, containing the Schiff base in mono or dianionic form, are generally stable both in the solid state and in solution, whereas the [SnR2Cl2(salopH2)] adducts slowly decompose in acetone or DMSO yielding [SnR2(salop)] and releasing HCl. All the [SnR2(salop)] and [SnRX(salop)(solvent)] complexes are fluxional in solution. The 119Sn NMR chemical shift is a function of the number of R groups. The X-ray single crystal diffraction study of [SnVin2(salop)] shows the metal to be five-coordinate in a distorted square pyramidal environment, SnC distances being 2.112(2) and 2.113(2) A, SnO 2.117(2) and 2.125(2) A and SnN 2.227(2) A. The whole structure consists of molecular units connected by weak intermolecular SnO interactions. In the complexes [SnX2(salop)(CH3OH)]·CH3OH complexes (X=Cl or Br), the tin atom is found in a strongly distorted octahedral environment with the SnO bond ranging from 1.995(3) to 2.055(2) A. The SnN bond is 2.116(4) A in the bromide and 2.171(3) A in the chloride complex.

Structure and volatility of copper complexes containing pyrazolyl-based ligands

Abstract Volatility studies, electrospray mass spectra and IR in vapour phase were carried out for a series of Cu(I) and Cu(II) complexes containing anionic pyrazole-based ligands such as 4-acyl-5-pyrazolonates and poly(pyrazolyl)borates. The volatility has been related to structural features and molecular parameters of the copper complexes. The crystal structures of [Cu(Q′)2(bipy)]·(acetone)1.5 (Q′=1-phenyl-3-methyl-4-benzoyl-pyrazolon-5-ato, bipy=2,2′-bipyridyl) and [Cu(QF)2(phen)]·EtOH (QF=1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolon-5-ato, phen=1,10-phenanthroline), have been also determined. In these complexes the copper atom is in a tetragonally distorted octahedral arrangement of the four O-atoms of pyrazolones with N2-donor ligand in equatorial position. Two sets of CuO distances, the longer being in axial positions, have been found. XRD data of films obtained from metal organic chemical vapour deposition MOCVD experiments on [Cu(poly(pyrazolyl)borate)(PR3)] complexes have also been reported.

Synthesis and x-ray crystal structures of tetrakis-(2,2,6,6-tetramethylheptane-3,5-dionato)bis(2,2′-bipyridyl)dibarium Ba2(thd)4(bipy)2 and catena-[dodecakis(2,2-dimethylpropanoato)bis(2,2,6,6-tetramethylheptane-3,5-dionato)tetra(pyridine)tetra(aqua) heptabarium] pyridine solvate {Ba7(piv)12(thd)2(py)4(H2O)4·2py}

Abstract Two new volatile mixed ligand barium complexes have been synthesized and their X-ray crystal structures determined. Ba2(thd)4(bipy)2 (1) consists of dimeric molecules; with two barium atoms linked by four bridging BaOBa bonds. The structure of {[Ba7(piv)12(thd)2(py)4(H2O)4]·2py} (2) contains Ba3 units and separate Ba atoms which are connected into infite chains through BaOBa bridges.

The reactivity of new (1,5-cyclooctadiene)rhodium acylpyrazolonates towards N- and P-donor ligands: X-ray structures of [Rh(1,5-COD)Qs], [Rh(1,5-COD)(phen)]Qs·0.5H2O (HQs=1-phenyl-3-methyl-4-(2-thenoyl)-pyrazol-5-one) and [Rh(1,5-COD)Br]2

Abstract Complexes [Rh(1,5-COD)(Q)] have been prepared by the reaction between [Rh(1,5-COD)Cl] 2 (1,5-COD=1,5-cyclooctadiene) and HQ (where HQ=1-phenyl-3-methyl-4-R-pyrazol-5-one: R=2-thenoyl ( HQ s ), 2-furanoyl ( HQ o ) or tert -butylacetyl ( HQ T ). [Rh(1,5-COD)(Q)] react with N 2 -donor ligands such as 1,10-phenanthroline (phen) or 2,2-bipyridyl (bipy) yielding ionic compounds [Rh(1,5-COD)(N 2 -donor)]Q. The substitutional lability of 1,5-COD in [Rh(1,5-COD)(Q)] versus mono- and di-organophosphine ligands was also investigated. In all cases 1,5-COD has been displaced. Reaction with two equivalents of PPh 3 gave, upon oxidation of the Rh(I) centre, [Rh(PPh 3 ) 2 (O 2 )(Q)] species containing a η 2 -peroxo-group. Reaction of [Rh(1,5-COD)(Q)] with the chelating P 2 -donor 1,2-bis(diphenylphosphino)ethane (dppe) or 4,4′-bis(diphenylphosphino)ferrocene (dppf) yields the peroxo Rh(III) compounds [Rh(dppe) 2 O 2 ]Q T and [Rh(dppf)O 2 (Q s )] or Rh(I) species [Rh(dppf-O 2 )(Q T )] containing the diphosphine in the oxidised form. Finally the reaction between [Rh(1,5-COD)(Q)] and allylbromide yields the well-known [Rh(1,5-COD)Br] 2 . All complexes have been characterised by analytical and spectral data (IR, 1 H and 31 P{ 1 H}-NMR spectra). The crystal structures of [Rh(1,5-COD)(Q s )], [Rh(1,5-COD)(phen)]Q s and [Rh(1,5-COD)Br] 2 , all containing a Rh(I) atom in a square coordinate environment, are also reported.

Organotin(IV) derivatives containing bis(diphenylphosphine)- and bis(diphenylphosphineoxo)alkanes

Abstract Di-organotin(IV)halides R2SnCl2 (R=Me or Ph) react with bis(diphenylphosphine)methane (DPPM) and bis(diphenylphosphine)ethane (DPPE) in ethanol in aerobic conditions yielding 1:1 adducts [R2SnCl2(DPPM–O2)] and [R2SnCl2(DPPE–O2)], respectively, containing the bis(diphenylphosphine) in oxidized form. The 1:1 adduct [SnMe2Cl2(DPPM–O2)] is composed of separate molecules containing six-coordinate tin, with the ligands coordinated in the bidentate O2-fashion, whereas [SnMe2Cl2(DPPE–O2)] is polymeric, with octahedral and centrosymmetric (all trans) tin atoms. In inert atmosphere, the interaction between R2SnCl2 and DPPM or DPPE does not take place. Mono-organotin halides RSnCl3 (R=Me, Bun or Ph) react with DPPM and DPPE yielding 1:1 adducts [RSnCl3(DPPM)] (R=Me, Bun or Ph) and [RSnCl3(DPPE)] (R=Bun or Ph).

THE STRUCTURAL CHEMISTRY OF IIA GROUP METAL DIKETONATES

The structural chemistry of the IIA group metal diketonates (M=Mg, Ca, Sr, Ba) is reviewed. A special attention is given to Ba compounds as the most challenging in MOCVD of HTSC thin films. The structures are described according to the structural principles: nuclearity, types of ligands and the coordination modes. Some correlations between the crystal structure, volatility and storage stability are discussed.

On the interaction of acylpyrazolonates with zinc(II) acceptors: the role of ancillary ligands

Abstract From the interaction of 1-phenyl-3-methyl-4-R-C(O)-pyrazol-5-one (HQT: R=CH2C(CH3)3; HQC: R=C6H11) with Zn(O2CCH3)2·2H2O in MeOH, derivatives [Zn(QT)2(H2O)] (1), [Zn(QT)2(MeOH)2] (2) and [Zn(QC)2(MeOH)2] (3) have been obtained. Heating 1 under vacuum afforded the anhydrous [Zn(QT)2] (4). Compounds 1 and 3 react with N2-donor ligands 1,10-phenanthroline (phen) and 2,2′-bipiridyl (bipy) in chloroform yielding [Zn(QT)2(phen)] (5), [Zn(QC)2(phen)] (6), [Zn(QT)2(bipy)] (7) and [Zn(QC)2(bipy)] (8), respectively. The adducts [Zn(QT)2(trime)] (9) and [Zn(QT)2(tmeda)] (10), respectively, were synthesised by carrying out the reaction between HQT and Zn(O2CCH3)2·2H2O in the presence of N,N,N′-trimethylethylenediamine (trime) or N,N,N′,N′-tetramethylethylenediamine (tmeda). In the X-ray crystal structure of 9 the zinc was found six-coordinate in a slightly distorted octahedral environment, due to steric requirements of acylpyrazolonato and diamine donors. Finally, 2 interacts in Et2O with imidazole (im), 1-methylimidazole (1-Meim), diethylamine (Et2NH) and 1-methylimidazoline-2-thione (Hmimt) affording [Zn(QT)2(imH)2] (11), [Zn(QT)2(N-Meim)2] (12), [Zn(QT)2(Et2NH)2] (13) and [Zn(QT)2(Hmimt)]2 (14), respectively. All compounds 1–14 have been characterised both in the solid and solution states with analytical and spectral data.

Lanthanide metal complexes containing the first structurally characterized β-diketonate acid stabilized by hydrogen bonding

Abstract A series of {H3O+}[MQs4]− (M=Tb, Eu, Lu; HQs=1-phenyl-3-methyl-4-thenoylpyrazole-5-one) complexes have been prepared and characterized; the presence of the {H3O+} cation stabilized by H-bonding to the pyridinic nitrogen of Qs has been confirmed by X-ray and spectroscopic (NMR, IR) investigations.

Synthesis, structure and luminescence properties of new rare earth metal complexes with 1-phenyl-3-methyl-4-acylpyrazol-5-ones

The isolation and characterization of new lanthanide complexes of formula [Ln(QL)3(EtOH)(H2O)], (Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; HQL = 1-phenyl-3-methyl-4-phenylacetylpyrazol-5-one) [Ln(QL)3(H2O)2] (L = La or Lu), [Ln(QS)3(EtOH)(H2O)] (Ln = Tb or Eu; HQS = 1-phenyl-3-methyl-4-thienoylpyrazol-5-one, [Tb(QO)3(EtOH)(H2O)] (HQO = 1-phenyl-3-methyl-4-furanoylpyrazol-5-one) [Tb(QF)3(H2O)2] (HQF = 1-phenyl-3-methyl-4-trifluoroacetylpyrazol-5-one) and [NBu4][Ln(Q)4] (Ln = Eu or Tb, Q = QF or QL) is reported. The crystal structure of the tris(β-diketonate) complexes [Nd(QL)3(EtOH)(H2O)], [Dy(QL)3(EtOH)(H2O)](EtOH), and [Eu(QS)3(H2O)(EtOH)] containing eight-coordinate lanthanide ions in a square antiprismatic environment has been determined. The coordination environment in the tetrakis complex [NBu4][Eu(QF)4] is also close to the square antiprismatic one. Photoluminescence (PL) and phosphorescence studies of selected derivatives are reported.

Interaction of Rh(I) with a new polydentate O4,N-donor pyrazolone able to form mononuclear, dinuclear and heterobimetallic compounds

Abstract Reaction of the new polydentate O4,N-donor ligand, namely 2,6-bis[4(1-N-phenyl-3-methyl-pyrazolium-5-one)carbonyl]pyridinium trichloride [H5QN]Cl3, with [Rh(COD)Cl]2 affords the dinuclear compound [Rh2(COD)2([H3QN]Cl3)] 1 which reacts with PPh3 forming [Rh(PPh3)2Cl2(HQN)] 2, able to interact with SnMe2Br2 yielding the heterobimetallic adduct [Rh(PPh3)2 Cl2(HQN)SnMe2Br2] 3; the X-ray structure of 2 shows the Rh(III) center in a slightly distorted octahedral environment with Cl atoms situated in cis-position and two phosphine groups in trans.