Sheo K. Dikshit

Synthesis and characterization of mixed ligand copper(I) complexes containing halides, triphenylarsine and N,N-dimethyl-N′-phenylthiourea (dmptH), N,N-dibutyl-N′-phenylthiourea (dbptH) or 1,3-thiazolidine-2-thione (tzdtH). The X-ray crystal structure of [Cu(PPh3)2(dmptH)Cl]

Abstract The arsine complexes [Cu(AsPh3)2(LH)X] (LH = N,N-dimethyl-N′-phenylthiourea (dmptH), N,N-dibutyl-N′-phenylthiourea (dbptH) or 1,3-thiazolidine-2-thione (tzdtH); X = Cl, Br, I) have been prepared and characterized on the basis of analytical, IR, electronic (UV-vis), 1H NMR, conductivity and magnetic measurements. In all cases there is a distorted tetrahedral environment around copper(I) and the ligands (LH) bind through thione sulphur atom to copper(I). We also report the crystal structure of complex [Cu(PPh3)2(dmptH)Cl] which shows that metal ion has a distorted tetrahedral geometry with bond lengths CuS = 2.459(2), CuCl = 2.308(1), CuP(1) = 2.305(1) and Cu  P (2) = 2.313(1) A . The NH is intramolecularly hydrogen bonded to Cl with a bond distance NH … Cl = 2.31 A

Substitution reactions of [CuI(PPh3)3X] (X = Cl, Br or I) with N,N-dimethyl-N′-phenylthiourea (dmptH), N,N-dibutyl-N′-phenylthiourea (dbptH) and 1,3-thiazolidine-2-thione (tzdtH)

Abstract Reactions of [Cu(PPh 3 ) 3 X] with the titled ligands yield The complexes have been characterized on the basis of analytical, IR, electronic (UV-vis), 1 H, 31 P and 13 C NMR, conductivity and magnetic measurements. In all cases there is a distorted tetrahedral environment around copper(I), and the ligands (LH) bind through the thione sulphur atom to copper(I).

Substitution reactions of [CuI(AsPh3)3X] (X = Cl, Br or I= with 3-phenyl-2-thioxoimidazolidin-4-one (ptiH) and 5-mercapto-1-phenyl-1,2,3,4-tetrazole (mptH)

Abstract Reactions of [Cu(AsPh 3 ) 3 X] with the title ligands yield [Cu(AsPh 3 ) 2 (LH)X] These complexes have been characterized on the basis of analytical, IR, electronic (UV-vis), 1 H NMR, conductivity and magnetic measurements. In all cases there is a distorted tetrahedral environment around copper(I), and the ligands (LH) bind through the thione sulphur atom to copper(I).

Reactions ofN-ethoxycarbonyltoluene-4-thiocarboxamide (ETTH),N-ethoxycarbonylpyrrole-2-thiocarboxamide (ETH), 2-thiopyrrole-1,2-dicarboximide (TPH) andN-carbamoylpyrrole-2-thiocarboxamide (CPTH) with [CuI(MPh3)3X] [M = P or As; X = Cl, Br or I] and AgI, CdII, HgII or PbII ions

SummaryReactions of [Cu(MPh3)3X] with the title ligands yield [Cu(MPh3)2(LH)X] (LH = ETTH, ETH, TPH and CPTH). Twenty-four complexes have been characterized on the basis of analytical, i.r., electronic and n.m.r. spectral and magnetic measurements studies. These complexes are unique examples of tetrahedral coordination with the aromatic ligand bonded to copper(I) through sulphur. Reaction with AgI, CdII, HgII or PbII results in abstraction of sulphur from ETTH to give the corresponding sulphides and an oxygenated form of the ligand.

SYNTHESIS, SPECTROSCOPIC, PHOTOPHYSICAL AND ELECTROCHEMICAL PROPERTIES OF CYANO-BRIDGED COPPER(I)-RUTHENIUM(II) COMPLEXES

Abstract Complexes of the formula [(N–N)Cu(AsPh 3 )CN] (N–N=2,2′–bipyridine, 1,10–phenanthroline) have been synthesized. Ru(bpy) 2 Cl 2 .2H 2 O and [( η 5 –cp)Ru(PPh 3 ) 2 Cl] react with [(N–N)Cu(AsPh 3 )CN] to give cyano-bridged compounds. IR spectral studies in the low frequency region (700–50 cm −1 ) and 4000–400 cm −1 region reveal cyano bridging in the complexes. Luminescence measurements suggest oxidation of metal centres (Cu I –Cu II and Ru II –Ru III ) on excitation at a charge transfer band. This has been substantiated with electrochemical studies of complexes which exhibit quasi-reversible reductions viz. Ru III ⧹Ru II and Cu II ⧹Cu I . The deposition of metallic copper is also observed at a potential of −1.55 V. Based on these data, a mechanism for photo-redox reaction of complexes has been presented. The properties of these bimetallic complexes are compared with those of parent complexes.

Thiocarboxamide complexes of rhodium, copper, palladium and platinum. The synthesis of [CuX(C4H4NCSNHCO2Et)(MPh3)2] (X = Cl or Br; M = As or P), [RhCl(MeC6H4CSNHCO2Et)2(PPh3)] and [M(MeC6H4CSNHCO2Et)2(PPh3)2] (M = Pd or Pt)

SummaryReaction ofN-ethoxycarbonylpyrrole-1-thiocarboxamide (EPTH) with [CuX(MPh3)3] yields [CuX(EPTH)(MPh3)2] (X = Cl or Br; M = As or P) and ofN-ethoxycarbonyltoluene-4-thiocarboxamide (ETTH) with [RhICl(PPh3)3], [Pd0(PPh3)4] and [Pt0(PPh3)4] yields [RhICl(ETTH)2(PPh3)], [Pd0(ETTH)2(PPh3)2] and [Pt0(ETTH)2(PPh3)2], respectively. The complexes have been characterised by analytical, i.r., electronic and n.m.r. spectral and magnetic measurements. All are tetrahedral except [RhCl(ETTH)2(PPh3)], which is square planar (trans).

Cyano-bridged copper(I)-ruthenium(II) complexes: syntheses, characterization and spectroscopic studies

Abstract New complexes of the formulae [(N-N)Cu(PPh3)CN] (N-N = 2,2′-bipyridine 1,10-phenanthroline) have been isolated and used to synthesize the novel cyano-bridged copper(I)-ruthenium(II) complexes [(N-N)Cu(PPh3)(μ-CN)Ru(bpy)2Cl]PF6 (bpy = 2,2′-bipyridine) and [(N-N)Cu(PPh3)(μ-CN)Ru(η5-Cp)(PPh3)2]PF6 (Cp = cyclopentadienyl anion). In addition, the complexes [(PPh3)2Cu(μ-CN)Ru(bpy)2Cl]PF6 and [(PPh3)2Cu(μ-CN)Ru(η5-Cp)(PPh3)]PF6 or BF4 have been synthesized using [(PPh3)2CuCN]. All the complexes have been characterized on the basis of elemental analyses, spectroscopic data (IR, UV-vis, 1H, 13C and 31P NMR), and magnetic and conductivity measurements. Spectroscopic data clearly indicate that in these complexes copper(I) and ruthenium(II) are bonded via a cyanide bridge.

Substitution reactions of chloro(η5-cyclopentadienyl)bis( triphenylphosphine)-ruthenium(II) with some thiocarboxa(i)mides

Abstract Reactions of [(η 5 -C 5 H 5 )RuCl(PPh 3 ) 2 ] with the ligands of the type RCSNHCOOC 2 H 5 (R = 2-pyrrole, 2-thiophene or 4-toluene), RCSNHCONHC 6 H 5 (R = 2-pyrrole) and 2-thiopyrrole-1,2-dicarboximide lead to the formation of diamagnetic compounds of the formula [(η 5 -C 5 H 5 )RuCl(PPh 3 )(ligand)]. These compounds were characterised by using analytical, magnetic, conductivity and spectroscopic (UV, VIS, IR and proton NMR) data. A distorted octahedral geometry is proposed for the complexes.

Transition Metal Complexes of N-Ethoxycarbonylthiophene-2-thiocarboxamide: Sulfur Abstraction from N-Ethoxycarbonylthiophene-2-thiocarboxamide by Ag(I), Cu(II), Pb(II), Hg(II), and Cd(II) Ions

Abstract Reactions of N-ethoxycarbonylthiophene-2-thiocarboxamide (LH) with transition metal ions viz., Cu(II), Ni(II), Ag(I), Ru(III), Rh(I), Rh(III), Pd(II) and Pt(II) lead to the formation of complexes of formulae CuL2, [NiL2(py)] (in the presence of pyridine), AgL, [RuL2Cl(H2O)], [Rh(LH) (PPh3)Cl]2,[RhL2Cl(H2O)], PdL2 and PtL2, respectively. Reactions of LH with Ag(I), Cu(II), Pb(II), Hg(II) and Cd(II) under refluxing condition yield the corresponding sulfides and the oxidation product of ligand (LH), in case of Ag(I), was characterised as N-ethoxycarbonylthiophene-2-carboxamide. All metal complexes have been characterised on the basis of analytical, conductivity, spectroscopic and magnetic measurement studies and their tentative structures are proposed.

Synthesis, spectroscopic, photophysical and electrochemical behaviour of ruthenium(II) and copper(I) isocyano-bridged complexes with polypyridine ligands: 2,2′-bipyridine and 1,10-phenanthroline

New binuclear complexes with [Cu(PPh3)3]+ and [Cu(PPh3)(N—N)]+ (N—N – 2,2′-bipyridine, 1,10-phenanthroline) moieties connected via the isocyanide group to [Ru(bpy)2(py)]+ and [Ru(phen)2(py)]+ have been prepared and isolated as PF6− salts. In addition, new trinuclear complexes, [{(PPh3)3Cu(μ-NC)}2Ru(bpy)2](PF6)2 and [{(N—N)-(PPh3)Cu(μ-NC)}2Ru(bpy)2](PF6)2, have been synthesized using [Ru(bpy)2(CN)2]. The complexes have been characterized by elemental analyses, i.r., n.m.r., u.v.–vis., FAB mass spectra and by conductivity measurements. The i.r. spectra reveal an increase in v;(CN) in the isocyano-bridged complexes compared to the mononuclear parent complexes. The complexes are luminescent with emission wavelengths in the 458–550 and 600–636 nm ranges. The half wave reduction potentials in MeCN are always more positive than those of the parent complexes. It is observed that the isocyano-bridged complexes are more powerful excited state reductants than the cyano-bridged, Cu(I)(μ-CN)Ru(II) complexes.