Complexes of metal ions with phosphorus or arsenic containing ligands,part XX. Chelates ofo-phenylenebis(diarylarsines) with palladium(II) and platinum(II) halides,pseudohalides and perchlorates

Summary Two ditertiaryarsines,o-phenylenebis(diphenylarsine), (pdpa) ando-phenylenebis(di-p-tolylarsine), (pdta) yield some new complexes of palladium(II) and platinum(II). These are: square planar M(pdta)X₂ · nCH₂Cl₂, [M = Pd, X = Cl, Br or NCS; M = Pt, X = Cl]; [Pt(A-A)₂] X₂ · nCH₂Cl₂, [(A-A) = pdta, X = Cl, NCS or ClO₄; (A-A) = pdpa, X=ClO₄] and [M₂(A-A)₂(NCS)₂] (ClO₄)₂ · nCH₂Cl₂, [M = Pd, (A-A) = pdta; M = Pt, (A-A) = pdpa]; distorted octahedral M(pdta)₂-X₂nCH₂Cl₂, [M = Pd, X = I; M = Pt, X = Br or I] and [Pd(pdta)₂(H₂O)₂](ClO₄)₂, and five coordinate [M(A-A)₂X] ClO₄ · nCH₂Cl₂, [M = Pd, Pt, (A-A) = pdta, X = I; M = Pt, (A-A) = pdpa, X = Br or I]. The [M₂(A-A)₂(NCS)₂] (ClO₄)₂ · nCH₂Cl₂ complexes are novel in the sense that they contain bridging thiocyanate together with ionic perchlorate. The stereochemical assignments have been made on the basis of i.r. and u.v. spectra as well as conductance data.     

Complexes of aminobenzylamines. part II. Complexes ofo-aminobenzylamine with palladium(II) and platinum(II)

Summary The reactions of K₂[MX₄] (M = Pd^II or Pt^II and X = Cl or Br) witho-aminobenzylamine (o-aba) have been studied in neutral aqueous solutions. Two types of complexes were isolated from these studies: [MLX₂] and [ML₂]X₂. Elemental analyses, conductivity measurements, i.r. and visible spectra suggest polymeric structures for [MLX₂] with the ligand,o-aba = L, acting as a bridge, and/or mononuclear structures for [ML₂]X₂.     

Nickel(II)- und Kobalt(II)-Komplexe des trans-2-Äthylmercapto-cyclohexyl-phenylphosphins

Preparation and properties of nickel(II) and cobalt(II) chelates of the bidentate ligand trans-2-ethylthio-cyclohexyl-phenylphosphine (ÄMCPP) are described. Three types of nickel(II) complexes have been obtained from ÄMCPP: the four-coordinated, square planar [Ni(ÄMCPP)₂]X₂ (X = J, Br, ClO₄); five-coordinated [Ni(ÄMCPP)₂X]X (X = Cl, NCS), [Ni(ÄMCPP)₂X]BPh₄ (X = Cl, NCS) and the octahedral [Ni(ÄMCPP)₂Cl₂]. Cobalt(II) forms tetrahedral 1.1-[Co(ÄMCPP)X₂] (X = Br, Cl) and 1.2-Co(ÄMCPP)₂X₂(X = Br, Cl, NCS) complexes. All compounds were characterized by electronic reflectance and absorption spectra, conductivity and magnetic measurements.     

Co-ordination compounds of diacetyldihydrazone and diacetylbis(monomethylhydrazone)

Summary Diacetyldihydrazone (DADH) forms only six-coordinate complexes with iron(II), cobalt(II), nickel(II) and zinc(II). In M(DADH)₂X₂ (M=Fe, X=Br or I; M=Co, X=I; M=Ni, X=Cl, Br or NCS) the ligand is chelating in the [M(DADH)₃]²⁺ cations, while in M(DADH)₂X₂ (M=Co, X=Cl or Br; M=Ni, X=Cl or Br) the ligand is probably bridging and bidentate. Diacetylbismonomethylhydrazone (DAMH), by contrast, forms predominantly tetrahedral complexes M(DAMH)X₂ (M=Fe or Co, X=Cl or Br; M=Ni, X=Br; M=Co, X=NCS; M=Zn, X=Cl, Br or NCS) and some octahedral complexes M(DAMH)₂X₂ (M=Co, X=NCS; M=Ni, X=Br). The i.r. spectra, electronic spectra and magnetic moments of the complexes are discussed.     

Nickel(II) and copper(II) complexes of 2,5-dimethyl-1,3,4-thiadiazole

Summary Nickel(II) and copper(II) complexes of 2,5-dimethyl-1,3,4-thiadiazole Ni(DTZ)X₂ (X = Cl or Br) and M(DTZ)₂X₂ (M = Ni, X = 1 or N03; M = Cu, X = Cl, Br or NO₃) have been prepared. The i.r. spectra show that in all the complexes the ligand is N,N- or N-bonded to the metal while the sulfur atom does not participate in coordination, and that the halide ions are coordinated forming terminal M-X bonds. The NO ₃ ^- group is coordinated in both the nitrato complexes. Magnetic moments of 3.07–3.29 B.M. for the nickel(II) and 1.86–1.92 B.M. for the copper(II) complexes were observed. The Ni(DTZ)X₂ complexes have a pseudo-tetrahedral [N₂X₂] coordination with N,N-bridging ligand molecules. The Ni(DTZ)₂X₂ and Cu(DTZ)₂X₂ complexes, with predominantly monodentate ligand, involve six-coordinate metal atoms with strong equatorial [N₂X₂] bonds and weaker axial bonds.Author to whom all correspondence should be directed.     

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].     

Synthesis and characterization of 1-Methyl-4-mercaptopiperidine complexes of nickel(II), palladium(II) and platinum(II)

Summary Complexes of formulae Ni(HRS)₂X₂ (X=Cl or Br), M(HRS)₂Y₂ (M=Ni or Pd; Y=NO₂ or C1O₄), Pd(HRS)X₂ (X=Cl, Br or I), Pt(HRS)X₂ (X=Cl or Br), Pt(HRS)₂(ClO₄)₂ and M(RS)₂ (M=Pd or Pt) where HRS and RS denote 1-methyl-4-mercaptopiperidine in the zwitterionic or in the thiolato form, respectively, have been prepared and characterized. In all the complexes the ligands are coordinated exclusively through sulphur. Polymeric structures consisting of square-planar geometry with sulphur-bridged metal atoms are proposed in each case.     

Zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethyl-pyrimidine-2(1H)-one

The following zinc(II), cadmium(II) and mercury(II) complexes of 4,6-dimethylpyrimidine-2(1H)-one (L) have been prepared and investigated by conductometric,IR and Raman methods: MX₂L₂ (M = Zn, X = Cl, Br(CHCl₃, I(CHCl₃, CF₃COO; M = Cd, X = Cl, Br CF₃COO; M = Hg, X = Cl, CF₃COO), Cd₂I₄L₃, Hg₃X₆L₂ (X = Cl, Br), Hg₃X₆L₄(X = Br, I), MX₂L₄·6H₂O (M = Zn, Cd, X = CIO₄, BF₄; M = Hg, X = CIO₄. The ligand is principally bonded through the unprotonated nitrogen atom and in some complexes also through the carbonylic oxygen atom. The zinc halide complexes are tetrahedrally coordinated, the trifluoroacetate ion is coordinated as a monodentate ligand.     

Chelate complexes of some NNO tridentate Schiff bases with iron(II), cobalt(II), nickel(II) and copper(II)

Summary The Schiff bases a-(C₅H₄N)CMe=NNHCOR (R = Ph, 2-thienyl or Me), prepared by condensation of 2-acetylpyridine with the acylhydrazines RCONHNH₂, coordinate in the deprotonated iminol form to yield the octahedral complexes, M[NNO]₂ M = Co or Ni; [NNOH] = Schiff base and the square-planar complexes, Pd[NNO]Cl. The Schiff bases also coordinate in the neutral keto form yielding the octahedral complexes (M[NNOH]2)Z2 (M = Ni, Co or Fe; Z = C104, BF₄ or N03) and complexes of the type M[NNOH]X2 (M = Ni, Co, Fe or Cu; X = Cl, Br or NCS). Spectral and x-ray diffraction data indicate that the complexes M[NNOH]X2 (M = Ni or Fe) are polymeric octahedral, as are the corresponding cobalt complexes having R = 2-thienyl. However, the cobalt complexes Co[NNOH]X2 (X = CI or Br; R = Ph or Me) and the copper complexes Cu[NNOH]CI₂ (R = Ph, 2-thienyl or Me) are five-coordinate, while the thiocyanato complex Co[NNOH](NCS)₂ (R = 2-thienyl) is tetrahedral.     

Coordination modes of 1-allyl benzotriazole: synthesis and characterization of cobalt(II), nickel(II), copper(II), copper(I) and silver(I) complexes

Summary The synthesis and coordination behaviour of 1-allylbenzotriazole (ABT), containing both -donating heterocyclic ring nitrogen(s) and a -bonding olefinic group, has been studied by complexation with Co^II, Ni^II, Cu^II, Cu^I and Ag^I salts. The solid complexes M(ABT)₂X₂ (M=Co, Ni or Cu and X=a counterion) and M(ABT)X (M=Cu or Ag and X=Br, I, or NO₃) have been characterised by¹H-n.m.r. (representative Cu^I species) and other physical data. Different modes coordination for the title ligand have been proposed based upon i.r. data which indicate the participation of a -donating ring nitrogen only in complexes with bivalent metal salts, and the involvement of both the ring nitrogen and the allylic olefinic component in bonding to a monovalent metal ion.¹H-n.m.r. data are qualitatively commensurate with participation of the allyl group in monovalent metal complexes.     

Cobalt(II), nickel(II) and copper(II) with 2-substituted benzimidazole complexes

Summary Complexes of stoichiometries M(Acbim)₂X₂·nH₂O and M(Bzbim)₂X₂·nH₂O (M = Co, Ni or Cu; Acbim = 2-acetylbenzimidazole, Bzbim = 2-benzoylbenzimidazole; X = Cl, Br, NO₃ or ClO₄; n = 0, 1 or 2) have been prepared and characterised by spectroscopic and physicochemical methods. The ligands coordinate through carbonyl oxygen and tertiary nitrogen.     

Complexes of 8-Aminoouinoline. II. The Infrared Spectra of the Bisand Mono(Aminoquinoline) Complexes of Metal(II) Halides

Abstract

The infrared spectra of the complexes M(aq)₂(H₂O)₂X₂ (M = Fe, Co, Ni, Cu; aq = 8-aminoquinoline; X =Cl, Br) have been determined over the range 4000-50 cm^?1. Absence of vM-X bands indicates that the halide is not coordinated to the metal ion and the complexes are correctly formulated [M(aq)₂-(H₂O)₂]X₂. Deuteration of the amino group and the effects of metal ion substitution enable assignment of the vM-NH₂, vM-N and vM-OH₂ modes as well as the amino group vibrations. ¹⁸ O-Labelling assists in identifying the vO-H, vO-H……X and δO-H bands. The spectra are consistent with trans-octahedral coordination and axial bonding of the water molecules. The far infrared spectra of the mono(aminoquinoline) complexes [M(aq)X₂]_n (M = Cu, Zn; X = Cl, Br) are consistent with the proposed structure of polymeric octahedral coordination involving both bridging and terminal M-X bonds. The vM-NH₂, vM-N, vM-X(terminal) and vM-X(bridging) bands are assigned by studying the effects of amino group deuteration, metal ion substitution and halide substitution.     

The preparation and characterization of some new nickel(II), copper(II), zinc(II) and cadmium(II) complexes of the pyrrole-2-carboxaldehyde Schiff bases ofS-alkyl esters of dithiocarbazic acid

Summary New complexes of general formulae [Ni(HL)₂], [ML]·H₂O and [Cu(HL)X] (H₂L = pyrrole-2-aldehyde Schiff bases ofS-methyl- andS-benzyldithiocarbazates; X = Cl or Br; M = Ni^II, Cu^II, Zn^II or Cd^II) were prepared and characterized by a variety of physicochemical techniques. The Schiff bases coordinate as NS bidentate chelating agents in [Ni(HL)₂] and [Cu(HL)X], and as tridentate NNS chelates in [ML] (M = Ni^II, Cu^II, Zn^II or Cd^II). Both the [Ni(HL)₂] and [NiL] complexes are diamagnetic and square-planar. Based on magnetic and spectroscopic evidence, thiolate sulphur-bridged dimeric square-planar structures are assigned to the [Cu(HL)X] and [ML] (M = Ni^II or Cu^II) complexes. The complexes ML (M = Zn^II or Cd^II) are polymeric and octahedral.     

Palladium(II) complexes with primary thioamides

Summary Palladium(II) complexes of thioacetamide, thiooxamide,N ^o,N ^o-dimethylthiooxamide and ethyl thiooxamidate have been prepared and investigated by electronic and i.r. spectroscopy. It is concluded that the ligands always act as monodentate sulphur donors, and that planar [PdL₄]X₂ (X = Cl, Br or ClO₄) compounds are formed. The(PdS) frequencies and the ligand field strengths are enhanced by electron donor groups and lowered by electron withdrawing groups.     

Palladium(II) and platinum(II) complexes of rhodanine and 3-methylrhodanine

Summary The following palladium(II) and platinum(ll) complexes of rhodanine (HRd) and 3-methylrhodanine (MRd) have been prepared: Pd(HRd)_1.5Cl₂, Pd(HRd)₂Br₂, Pd(HRd)₂Br₂ · 0.25 EtOH, M(MRd)₂X₂ [M = Pd, X = Cl (0.25 EtOH) or Br; M = Pt, X = Cl or Br], Pd(MRd)₃Br₂, and M(MRd)₄(ClO₄)₂ (M = Pd or Pt). The ligands are coordinated to the metal through the thiocarbonylic sulphur atom. Pd(HRd)_1.5Cl₂ has presumably a structure such as (X = Cl or Br) complexes have a trans-planar coordination. Pd(MRd)₂X₂ (X = Cl or Br) complexes arecis-planar coordinated. Pd(MRd)₃Br₂ has presumably a square coordination with two MRd molecules and two CI ionscis-coordinated in the equatorial plane, and a MRd molecule and a Cl ion weakly bonded in apical position. The M(MRd)₄(ClO₄)₂ complexes have square planar coordination.Author to whom all correspondence should be addressed.     

Metal Complexes of Aniline: Infrared and Raman Spectra

Abstract

The literature for the years 1965–1987 has been searched for all significant papers which refer to the vibrational spectra of metal complexes of aniline and substituted anilines. These papers have been reviewed with particular reference to isotopic labelling and metal ion substitution studies as assignment techniques and to the structural and bonding information which can be derived from the spectra. Compounds of the following classes are included: [M(an)₂X₂] (M = Mn, Co, Ni, Cu, Zn, Cd, Hg; an = aniline, X - Cl, Br, I, NCS); cis- and trans-[Pt(an)₂X₂] (X = Cl, Br, I, NO₂); [M(R-an)₂X₂] (M = Mn, Co, Ni, Cu, Zn; R-an = o-, m- and p-toluidine and other substituted anilines; X = Cl, Br, I); aniline adducts of metal β-ketoenolates; the complexes trans-[PtL(R-an)X₂] (L = CH₂?CH₂ or CO, R-an = aniline or a substtuted aniline, X = Cl, Br); and other miscellaneous systems comprising aniline as a ligand.     

Untersuchungen an 1,2-Komplexen der Nickel(II)-halogenide mit N-substituierten Aminoäthylpyridinen-(2)

In the solid state complexes of the type MiL₂X₂ (L = N-substituted β-aminoethyl-pyridine; X = Cl, Br, J) have a cis-octahedral (X = Cl, Br) or a distorted trigonal bipyramidal structure (X = J). In solutions in acetone a partial dissociation occurs with the formation of NiLX₂, L, NiL₂X⁺, and X^?. Using a spectrophotometric method stability constants K_2S of the complexes NiL₂X₂ are determined. A correlation exists between log K_2s and the pK- values of the quarternary ammonium ions derived from the ligands L. Sterical factors cause the exeptional position of the chelates of β-methylaminoethylpyridine-(2).     

Synthesis and spectral studies of copper(II), nickel(II), cobalt(II) and vanadyl(II) complexes of tridentate Schiff bases of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide

Summary Metal(II) chelates of Schiff bases derived from the condensation of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide with o-aminophenol (KAAP), o-aminothiophenol (KAAT) or o-aminobenzoic acid (KAAB) have been prepared and characterized. The complexes are of the type [M(N₂X)]₂ for M = Cu^II and M(NX)₂·nH₂O for M = Ni^II, Co^II and VO^II (X = phenolic oxygen, thiophenolic sulphur or carboxylic oxygen; n = 0 or 2). Conductivity data indicate that the complexes are non-ionic. The Schiff bases behave as dibasic tridentate ligands in their copper(II) complexes and as monobasic bidentate ligands in their nickel(II), cobalt(II) and vanadyl(II) complexes. The subnormal magnetic moments of the copper(II) complexes are ascribed to an antiferromagnetic exchange interaction arising from dimerization. Nickel(II) and cobalt(II) complexes are trans octahedral whereas vanadyl(II) complexes are square pyramidal     

Tridentate chelate π-bonded complexes of rhodium(I), iridium(I), and iridium(III) and chelate σ-bonded complexes of nickel(II), palladium(II), and platinum(II) formed by intramolecular hydrogen abstraction reactions

2,2′-Bis(o-diphenylphosphino)bibenzyl, o-Ph₂PC₆H₄CH₂CH₂C₆H₄PPh₂-o (bdpbz), is dehydrogenated by various rhodium complexes to give the planar rhodium(I) complex

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, from which the ligand, 2,2′-bis(o-diphenylphosphino)-trans-stilbene (bdpps) can be displaced by treatment with sodium cyanide. The stilbene forms stable chelate olefin complexes with planar rhodium(I) and iridium(I) and with octahedral iridium(III). On reaction with halide complexes of nickel(II), palladium(II) or platinum(II), the stilbene ligands

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(R = Ph or o-CH₃C₆H₄) lose a vinyl proton in the form of hydrogen chloride to give chelate, planar σ-vinyls of general formula =CHC₆H₄PR₂-o) (M = Ni, Pd, Pt; X = Cl, Br, I) of high thermal stability; analogous methyl derivatives =CHC₆H₄PR₂-o) are obtained from Pt(CH₃)₂(COD) (COD = 1,5-cyclooctadiene) and the stilbene ligands. The bibenzyl also forms chelate σ-benzyls HCH₂C₆H₄PPh₂-o) (M = Pd, Pt; X = Cl, Br, I). The ¹H NMR spectra of the o-tolyl methyl groups in the compounds =CHC₆H₄PR₂-o) (M = Ni, Pd, Pt; R = o-CH₃C₆H₄) vary with temperature, probably as a consequence of interconversion of enantiomers arising from restricted rotation about the M---P and M---C bonds. Possible mechanisms for the dehydrogenation reactions are briefly discussed.     

Coordination compounds of hydrazine derivatives with transition metals,Part 17. Nickel (II) and cobalt(II) chelates with pyridine-2-aldehyde semi- and thiosemicarbazone

Summary The chelation abilities of both pyridine-2-aldehyde semicarbazone (Pysc) and thiosemicarbazone (Pytsc) towards Ni^II and Co^II salts have been investigated. A series of pentacoordinate monoligand chelates: Ni(Pysc)X₂, Ni(Pytsc)X₂ and Co(Pysc)X₂ and octahedral bis ligand chelates Ni(Pysc)₂X · NO₃ Ni(Pytsc)₂X₂ and Co(Pysc)₂X₂ have been isolated and identified. In these chelates, both Pysc and Pytsc act as neutral tridentate ligands. The deprotonated form of Pyts, which arises through enolization, is identified in N^II chelates and is of the type Ni(PytscH)₂ and Ni(PytscH)X. Spectral and magnetic measurements are presented and attention is drawn to the effect of temperature on the solution spectra of some of the chelates.