Copper(I) complexes of neutral,deprotonated and protonated 4,6-dimethylpyrimidine-2 (1H)-thione

Summary The following copper(I) complexes of 4,6-dimethylpyrimidine-2(1H)-thione (HL), its protonated cation (H₂L⁺) and deprotonated anion (L^–) have been prepared: CuL, Cu(HL)X (X = Cl, Br or I), Cu(HL)₂X (X = C1 or Br), Cu₂(HL)₃Br₂, Cu(H₂L)X₂ (X = Cl or Br), Cu₃(HL)₂LA₂ (A = ClO₄ or BF₄ ). The i.r. spectra show that in all the HL and L^– complexes and in the Cu(H₂L)Br₂ complex, the ligands are S, N coordinated to the metal ion, while in Cu(H₂L)Cl₂ only the thiocarbonylic sulphur is coordinated, probably bridging two copper(I) atoms. Thev(CuN) (288–317 cm^–1 ) andv(CuS) (191–225 cm^–1 ) have uniform frequency values in all the complexes. The halide ions are, in all their complexes, wholly or in part coordinated giving twov(CuX) bands which may indicate an asymmetrical Cu-X Cu halide bridging bond.Author to whom all correspondence should be directed.     

Silver(I) complexes ofN-ethylthiourea. An infrared study

Summary The following silver(I) complexes ofN-ethylthiourea, L, have been isolated in the solid state: AgLX (X = Cl, Br, ClO₄, BF₄, and CF₃CO₂), Ag₂L₃X₂ (X=ClO₄, BF₄ and CF₃CO₂), AgL₂ClO₄, AgL₃X (X = Cl, Br, I, ClO₄, BF₄ and CF₃CO₂). The decrease of the(CS) and (SCN₂) frequencies in the i.r. spectra of the complexes indicates S-coordination of the ligands. The(AgS) frequencies lie in the 267–252 cm^–1 range for terminal and 240-210 cm^–1 range for bridged or long Ag-S bonds. The following structures may be proposed for the complexes. AgLX (X = Cl and Br), polymeric trigonal coordination with bridging halide ions; Ag₂L₃A₂ (A = ClO₄ and BF₄), polymeric trigonal coordination with three bridging sulphur atoms; AgL₂ClO₄, polymeric tetrahedral coordination with four bridging sulphur atoms; AgL₃A (A = ClO₄ and BF₄), dimeric tetrahedral coordination with two terminal and two bridging sulphur atoms; AgLO₂CCF₃ and Ag₂L₃(O₂CCF₃)₂, trigonal and/or tetrahedral coordination with terminal sulphur bonds and bridging CO₂ groups; AgL₃O₂CCF₃, tetrahedral coordination with terminal sulphur bonds and a monodentate CO₂ group. In the trifluoroacetato complexes, a(AgO) band is observed at 185–209 cm^–1. The AgL₃X complexes (X = Cl, Br and I) show two(AgX) and two(AgS) bands with rather low frequencies corresponding to long metal-ligand bond distances.     

Gold(I) complexes of thioamides

Summary Gold(I) forms linear [AuL₂]X complexes (X = Cl, Br, I or CIO₄) with thioacetamide and thiobenzamide, AuLX compounds with thiobenzamide (X = CI or Br),N, N-dimethylthioformamide (X = Cl, Br or 1) andN-dimethylthioacetamide (X = CI, Br or 1). Thev(AuS) vibrations are assigned in the 320-260 cm^–1 range. The i.r. spectra further suggest hydrogen bonding between the ligands and the anions. The conductivity measurements indicate dissociation of the [AuL₂]X complexes (X = halide) and coordination of X in solution.Presented in part at the XIX ICCC, Prague, 1978.     

Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

Coordination Polyhedra OsXn(X = F, Cl, Br, I) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of compounds containing complexes [Os _a X _b ] ^z–(X = F, Cl, Br, I). Atoms of Os(V) at X = F and Cl, of Os(IV) at X = Cl, Br, and of Os(III) at X = Br were found to exhibit a coordination number of 6 with respect to the halogen atoms and to form OsX₆octahedra. The coordination polyhedra of Os(III) for X = Cl, I are square pyramids OsX₄. Each Os(III) atom forms one Os–Os bond; as a consequence, the OsBr₆octahedra share a face in forming Os₂Br^3– ₉complexes, while the OsX₄pyramids (X = Cl, I) dimerize to produce [X₄Os–OsX₄]^2–ions. The influence of the valence state of the Os atoms and of the nature of the halogen atoms on the composition and structure of the complexes formed and some characteristics of the coordination sphere of Os were considered.     

(N,N, N′, N′-tetramethylethylenediammonium)Cu2X6 (X=Cl,Br): crystal structure and magnetic interactions

Summary The crystal structures of (Me₄enH₂)Cu₂Cl₆ and (Me₄enH₂)Cu₂Br₆ have been determined. The triclinic crystals contain chains of symmetrically bibridged [Cu₂X₆]^2– dimers. Within the dimers the Cu–X distances average 2.299 Å (Cl) and 2.408 Å (Br) and the Cu–X–Cu angles are 96.4(1)^o (Cl) and 95.7(1)^o (Br). Longer Cu–X bonds, 2.679(1)Å (Cl) and 2.761(3)Å (Br), link dimers together into infinite chains via asymmetrical bridges. The bridging angles for the asymmetric bridge are 92.2(1)^o (Cl) and 89.4(1)^o (Br). Magnetic susceptibility data for both compounds are indicative of antiferromagnetic coupling. Analyses of the data yields J/k=–23(1)K (Cl) and –82(2)K (Br) for the interdimer coupling and J/k=–5(1)K (Cl) and –4(1)K (Br). The intradimer coupling for the chloride is in accord with magneto-structure relations deduced for similar salts. Similarly, the increased antiferromagnetic contribution upon substitution of Cl by Br follows trends previously observed.     

Disordered Crystal Structures of Three Halogenated Propionamides CF3CFXCONH2 (X = Cl, Br, I)

The disordered crystal structures of three halogenated propionamides of the general formula CF₃CFXCONH₂, X = Cl (I), Br (II), and I (III), were studied by X-ray diffraction (CAD-4 automatic diffractometer, MoK ). All these structures are monoclinic with space group P2 _1/c . The structures were solved by direct methods and refined by the full-matrix least-squares procedure anisotropically for nonhydrogen atoms. It was established that structures II and III is isomorphic to each other, whereas structure I is not isomorphic to them, although it has a similar molecular packing. The same crystallographic position is statistically (with different probabilities) occupied by two identical molecules (I, II, or III) with different configurations, which may be regarded as one disordered molecule where two substituents at the C₂ atom (halogen X atom and CF₃ group) are mutually statistically interchangeable in the space of the unit cell. The amide fragment (–CONH₂) of these disordered molecules is practically ordered. The crystal structures of I, II, and III have a developed system of intermolecular H-bonds of N–H O type and unusual intramolecular H-bonds of N–H F–C type.     

Thermally induced isomerisation and decomposition of diethylenetriamine complexes of nickel(II) in the solid state

Summary Complexes [NiL₂]X₂·nH₂O (L=diethylenetriamine; n=O when X=CF₃CO₂ or CCl₃CO₂; n=1 when X=Cl or Br, and n=3 when X=0.5SO₄ or 0.5SeO₄) and NiLX₂·nH₂O (n=1 when X=Cl or Br; n=3 when X=0.5SO₄ or 0.5SeO₄) have been synthesised and investigated thermally in the solid state. NiLSO₄ was synthesised pyrolytically in the solid state from [NiL₂]SO₄·[NiL₂]X₂ (X=Cl or Br) undergo exothermic irreversible phase transitions (242–282° C and 207–228° C; H=–11.3 kJ mol^–1 and –1.9 kJ mol^–1 for [NiL₂]Cl₂ and [NiL₂]Br₂, respectively). [NiL₂]-phenomenon (158–185° C; H=2.0 kJ mol^–1). NiLX₂· nH₂O (n=1 or 3) undergo simultaneous deaquation-isomerisation upon heating. All the complexes possess octahedral geometry.     

Cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole and 2,5-bis(methylmercapto)-1,3,4-thiadiazole

Summary Some cobalt(II), nickel(II), copper(II) and copper(I) complexes of 2-mercapto-5-methyl-1,3,4-thiadiazole (mttz) and 2,5-bis(methylmercapto)-1,3,4-thiadiazole (bmttz) have been prepared and studied by conductometric and magnetochemical methods and by electronic and i. r. spectroscopy. The complexes CoX₂ · 2L (L=mttz, X=Cl, Br or I; L=bmttz, X=Br or I), CoCl₂ · bmttz are pseudotetrahedral, and the complexes NiX₂ · mttz (X=Cl or Br), NiCl₂ · 1.3 bmttz, NiBr₂ · 1.5 bmttz are pseudooctahedral. The complex Co₃(OAc)₂ · 4(mttz-H) · 2H₂O has an undefinite constitution. The polynuclear complexes CuCl₂ · 1.3 mttz and CuBr₂ · 1.2 mttz contain presumably pseudotetrahedral chromophores, the chloride having a subnormal magnetic moment. The CuX₂ · 2 bmttz (X=Cl, Br or NO₃) complexes have a six coordination with bridging ligand molecules. In the CuX · 2 mttz (X=Cl, Br or ClO₄) complexes the anions are coordinated, while in the CuClO₄ · 2 bmttz complex the perchlorate anion is ionically bonded.     

Copper(I) and copper(II) complexes of diamino-dithioether ligands

Summary Copper(II) salts were reacted with two diamino-dithioether ligands, i.e. 1,3-di(o-aminophenylthio)propane (abbreviated H₂L¹) and 1,2-di(o-aminophenylthio)xylene (abbreviated H₂L²). Mixtures of copper(I) and copper(II) complexes were obtained with Cl^– and ClO ₄ ^– counterions. The major products were the copper(I) complexes, which were obtained pure after recrystallisation from MeCN-MeOH. The ligands lose two protons from the amine functions to form copper(I) complexes of general formula [CuL]X, where X = ClO ₄ ^– or Cl^–. The complexes were oxidised to [CuL]X₂ with H₂O₂ in DMF. Cu(NO₃)₂ on the other hand gave [CuH₂LNO₃]NO₃.     

Rhodium(1) carbonyl complexes with alkyl sulphoxides and sulphides

Summary Rhodium(I) carbonyl complexes, namely Rh(CO)X(R₂SO)₂ (R = Me, n-Pr or n-Bu) and Rh(CO)X(R₂S)₂ (R = Me, Et or i-Pr) and X = CI or Br, have been prepared and characterized. The compounds Rh(CO)X[P(OPh)₃]₂ X = Cl or Br, have also been isolated. In the R₂SO and R₂S complexes, the carbonyl stretching frequencies occur atca. 2020–2025 cm^–1 andca. 1950–1980 cm^–1 respectively. In the R₂SO ligand containing complexes v(S-O) occurs atca. 1100–1125 cm^–1 indicative of metal-sulphur coordination. In presence of HBF₄, the addition of an excess of Me₂SO to (OC)₂Rh(-Cl)₂Rh(CO)₂ gives [Rh(Me₂SO)₆]³⁺ in which the central metal atom undergoes spontaneous oxidation from Rh¹(d⁸) to Rh^III(d⁶). The complexes have been characterized additionally by u.v.vis. spectra, conductivity measurements and by elemental analyses.     

A13C nuclear magnetic resonance study of some linear alkynyl gold(I) and silver(I) complexes

Summary Phenylacetylide gold(I) and silver(I) compounds of the type [n-Bu₄N][M(C=CPh)₂], (1) and [n-Bu₄N][XMC=CPh], (2) have been studied by¹³C n.m.r. spectroscopy and their chemical shifts are reported for the first time. The shielding of the alkynyl carbon linked directly to the metal in (2) isca. 10–15 ppm less than the analogous carbon in (1) (M=Au), andca. 6–11 ppm less in the silver complexes (M=Ag). The variation in chemical shift depends on the nature of X(X=Cl, Br, I, C₂Ph and Ph₃P) and indicates greatly different degrees of polarization of the Au-C= (or Ag-C=) bonds in (1) and (2). I.r. spectra of the title compounds are reported and confirm the weakness of ML back-bonding. Comparison is also made with¹³C and i.r. data for platinum, and mercury complexes.     

Studies on nickel (II) complexes of some poly(1-pyrazolyl)alkane ligands

Summary The coordinating behaviour of tris(1-pyrazolyl)methane, HCpz₃ and 2,2-bis(1-pyrazolyl)propane, Me₂Cpz₂ ligands towards nickel(II) salts has been investigated. Tris(1-pyrazolyl)methane yields stable, solid complexes of the type [Ni(HCpz₃)X.H₂O].nH₂O (X=Cl, n=2; AcO, N=1) and [Ni(HCpz₃)₂]X₂ (X = Br, I, NO₃, or IO₄) whilst Me₂Cpz₂ ligand does not. However, Me₂Cpz₂ in the presence of poor coordinating polyanions such as BF ₄ ^– and PF ₆ ^– reacts readily to give stable complexes of the type [Ni(Me₂Cpz₂)₂X]Y (X=Cl, NO₃, or AcO and Y=BF₄ or PF₆). The complexes have been characterised by elemental analysis, magnetic moments, electronic and infrared absorption spectra. An octahedral structure has been proposed for the complexes [Ni(HCpz₃)X₂ · H₂O] · nH₂O with one water molecule occupying an axial position. An octahedral structure has also been proposed for the complex ions, [Ni(HCpz₃)₂]²⁺ and [Ni(Me₂Cpz₂)₂X]⁺(X = NO₃ or AcO) with the anion X acting as a bidentate ligand whilst [Ni(Me₂Cpz₂)₂Cl]⁺ is considered to have a square pyramidal structure.     

Metal complexes of sulfur-nitrogen chelating agents. Part 12. The chemistry of nickel(II), palladium(II), cobalt(II) and copper(II) complexes of N2S2 and N3S2 donor systems

Summary Nickel(II), palladium(II), cobalt(II) and copper(II) complexes of the ligandN,N-1,2-propane-bis(methyl 2-amino-cyclopent-1-ene-dithiocarboxylate) (H₂L¹),N,N-1,3-propane-bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate) (H₂L²) andN,N-[bis(methyl 2-aminocyclopent-1-ene-dithiocarboxylate)] diethylenetriamine (H₂L³) have been synthesised. Both H₂L¹ and H₂L² form complexes of the type ML, and all but the copper(II) complexes, are square planar. In the copper(II) complexes tetrahedral distortion is significantly more with CuL². From H₂L³ square planar complexes of the type [M(HL³)X] (M=Ni, X=Cl, Br, I or SCN; M=Pd, X=Cl or Br) have been obtained in which the donor unit involved is N₂SX. The composition of the cobalt(II) and copper(II) complexes is [M(H₂L³)X₂] (X=Cl or Br) which contain the chromophore [MN₃X₂].     

Cyclic ligands with fixed co-ordination geometry. Part 6(1). Chalcogenanthrenes as bridging ligands in dinuclear complexes of rhenium(I) and platinum(IV)-X-ray crystal structure of di(μ-chloro) (μ-2, 3, 7, 8-tetramethoxyselenanthrene) hexamethyl diplatinum(IV)

Summary The chalcogenanthrenes Vn₂EE; 2, 3, 7, 8-tetramethoxythianthrene (E=E=S), 2, 3, 7, 8-tetramethoxydibenzothiaselenin (E=S, E=Se), and 2, 3, 7, 8-tetramethoxyselenanthrene (E=E=Se), react with [{ReBr(CO)₃(THF)}₂] and [{PtXMe₃}₄] (X=Cl or Br) to give the dinuclear complexes [(fac-L₃M)₂(-X)₂ (-Vn₂EE)] (M=Re, L=CO, X=Br; M=Pt, L=Me, X=Cl or Br) in which the chalcogenanthrenes reveal a hitherto unknown co-ordination mode as bridging ligands. Telluranthrene (Pn₂ Te₂), however, forms mononuclear complexes of compositionfac-[L₃MX(Pn₂Te₂)] (M=Re, L=CO, X=Br; M=Pt, L=Me, X=Br) with a chelating chalcogenanthrene ligand. Whereas the rhenium compounds are not stable enough in solution to be studied by i.r. spectroscopy, the platinum compounds can be well characterised by their¹H n.m.r. spectra. Furthermore, the results of a single-crystal structure determination of [Pt₂Cl₂Me₆(Vn₂Se₂)] are reported. The Pt–Se distance of 259 pm indicates a relatively weak interaction between the chalcogenanthrene and the remaining dinuclear fragment of the molecule.     

Gold(I) complexes with tertiary phosphine sulfide ligands

Phosphine sulfides and their gold(I) complexes with general formula R₃P=S—Au—X (X = Cl^–, Br^– or CN^–) were prepared and characterized by elemental analyses, i.r. and ³¹P-n.m.r. spectroscopy. A decrease in the i.r. frequency of the P=S bond in the ligands upon complexation, is indicative of S coordination to gold (I). The ³¹P-n.m.r. spectra revealed that electronegativity of the substituents and angles between them were the two most important factors influencing the ³¹P-n.m.r. chemical shifts. The phosphorus resonance was observed to be more downfield in alkyl substituted phosphine sulfides as compared to the aryl substituted phosphine sulfides. Ligand scrambling in the Cy₃P=S—Au—CN complex in solution, to form [(Cy₃P=S)₂Au]⁺ and [Au(CN)₂]^–, was investigated by ¹³C and ¹⁵N-n.m.r. spectroscopy. Equilibrium constants (K _eq) for scrambling of the Cy₃P=S—Au—CN complex and for its analogue, Cy₃P=Se—Au—CN were measured by integrating the ¹³C-n.m.r. at 297 K and were found to be 0.147 and 1.81 respectively.     

Preparation and properties of chiral complexes of Cu(II) with (S)-2-[(N-benzylprolyl)amino]benzaldehyde oxime,catalysts of azlactone hydrolysis

Two Cu(II) complexes of (S)-2-[(N-benzylprolyl)amino]benzaldehyde oxime (L) were isolated. The complex Cu[(LH^–1)(Cl)] is green, whereas Cu₂(LH₂)_–2 is red-brown. The structure of these complexes was proved by elemental analysis, IR and UV spectroscopy. The average molecular masses ( ) of the complexes in ethanol were determined by precision ebulliometry. The concentration dependence of the values of these complexes is consistent with the existence of the following equilibria in ethanol: Cu[(LH_–1)(Cl)] + EtOH Cu[(LH_–1)(HOEt)]⁺+Cl⁺ and [Cu₂(LH_–2)₂] + EtOH 2[Cu(LH-_–2)(HOEt)]. The equilibrium constants of these two reactions were determined. Both [Cu(LH_–1)(Cl)] and [Cu₂(LH_–2)₂] catalyze with equal efficiency the hydrolysis of 2-methyl-4-benzyl-5(4H)-oxazolone in aqueous solutions at a given pH. The UV spectra of both complexes in water at similar pH values are identical. Thus, both complexes must be interconvertible in aqueous solutions. Furthermore, the absence of any electrophoretically mobile particles in neutral aqueous buffers is an indication that the complexes [Cu₂(LH^–2)₂] and [Cu(LH^–2)(H₂O)] are the predominant species in solution under these conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2270–2275, October, 1991.     

Transition metal chemistry of oxime-containing ligands,part XI. Copper(II) complexes of syn-phenyl-2-pyridylketoxime and syn-methyl-2-pyridylketoxime

Summary Some copper(II) complexes of the types: Cu(HPPK)-(PPK)X, Cu(HMPK)(MPK)X (where HPPK = syn-phenyl-2-pyridylketoxime, HMPK = syn-methyl-2-pyridylketoxime and X = Cl^–, Br^–, I^–, NO₃ ^–, SCN^– or SeCN^–) Cu(HPPK)₂SO₄ 3 H₂O and Cu(HMPK)₂SO₄ · 3 H₂O were synthesized and characterized by analysis, magnetic susceptibility, e.s.r., reflectance and i.r. spectral measurements. The spectral data suggest that Cu(HPPK)(PPK)X and Cu(HMPK)(MPK)X containcis square-coplanar [Cu(HPPK)(PPK)]⁺ and [Cu(HMPK)(MPK)]⁺ units respectively, linked by weakly coordinated anions, giving infinite polymeric highly distorted octahedral chain structures, whereas Cu(HPPK)₂SO₄ · 3H₂O and Cu(HMPK)₂SO₄ · 3 H₂O have acis distorted octahedral structure containing two ligand molecules of ketoxime and a bidentate sulphate group. The polycrystalline e.s.r. spectra suggest a distorted octahedral stereochemistry for the Cu^II ion involving a ground-state. By using e.s.r. and reflectance spectral data, the orbital reduction parameters, k₁₁ and k₁ were calculated and interpreted in terms of molecular orbital coefficients.     

Nicke(II) halide complexes with hypoxanthine and xanthine

Summary Ni(LH)₃LX complexes (LH=hypoxanthine or xanthine; X=Cl, Br or I) are formed by boiling under reflux 2:1 molar mixtures of LH and hydrated NiX₂ in HC(OEt)₃–MeCO₂Et. The new complexes appear to be linear chain-like polymers, characterized by bidentate monoanionic L^– ligands singly bidging between adjacent Ni²⁺ ions. A coordination number six is attained by the presence of three terminal unidentate LH and one X ligand in the first coordination sphere of each Ni²⁺ ion. The neutral LH and monoanionic L^– ligands bind exclusivelyvia ring nitrogens to Ni^II. The probable binding sites of the uni- and bi-dentate hypoxanthine and ligands in the new complexes are discussed.Presented in part at the 3rd Chem. Congress of North America (LH=xanthine) and the XXVI ICCC (LH=hypoxanthine), see refs. 1 and 2, respectively.     

A spectroscopic study of cobalt(III) furyldioximates

Summary The electronic properties of a series of cobalt(III)trans-furyldioximato-complexes of the type [CoB(FH)₂X] (B=NH₃, X=Cl, Br, I or NO₂; B=pyridine (py) or thiocarbamide (thio), X=Cl or Br; B=imidazole (imid), X=Br), [Co(FH₂)(FH)Cl₂] and [Co(thio)₂(FH)₂]NO₃ were studied by i.r., u.v. and¹H and¹³C n.m.r. spectra The results were compared with those from the corresponding dimethylglyoximato-complexes. It was concluded that -conjugation over the equatorial plane in the furyldioximates is greater than in the dimethylglyoximates. There is some evidence of thetrans-influence of the anionic ligands in the ammines which are in the order NO ₂ ^– >Br^–>Cl^–.