Complexation of palladium cyanide with imidazolidine-2-thione and its derivatives

Summary Pd(CN)₂ reacts with imidazolidine-2-thione (Imt), 1,3-diazinane-2-thione(Diaz), 1,3-diazipnane-2-thione (Diap) and their derivatives to yield complexes of stoichiometry [PdL₂(CN)₂] or [PdL(CN)₂] (L = Imt, Diaz or Diap and L = Imt having N-Me, Et or Pr substituents), which were characterized by elemental analysis, i.r., ¹H and ¹³C n.m.r. spectroscopy. Both mono- and bis ligand complexes are thought to be square planar with the monoligand binding to metal via sulphur (bridging) and the bis ligand via the monodentate thione group. The ¹³C enriched Pd(¹³CN)₂ complex was prepared and the ¹³C n.m.r. recorded. The C-2 resonance of ¹³C n.m.r. of Imt, Diaz or Diap complexes of the copper(I), silver(I), gold(I) and palladium(II) were compared.     

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.     

Syntheses,crystal structures and magnetic properties of two cyano-bridged two-dimensional assemblies [Fe(salpn)]2 [Fe(CN)5NO] and [Fe(salpn)]2[Ni(CN)4]

Two cyano-bridged assemblies, [Fe^III(salpn)]₂[Fe^II(CN)₅NO] (1) and [Fe^III (salpn)]₂[Ni^II(CN)₄] (2) [salpn = N, N-1,2-propylenebis(salicylideneiminato)dianion], have been prepared and structurally and magnetically characterized. In each complex, [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– coordinates with four [Fe(salpn)]⁺ cations using four co-planar CN^– ligands, whereas each [Fe(salpn)]⁺ links two [Fe(CN)₅NO]^2– or [Ni(CN)₄]^2– ions in the trans form, which results in a two-dimensional (2D) network consisting of pillow-like octanuclear [—M^II—CN—Fe^III—NC—]₄ units (M = Fe or Ni). In complex (1), the NO group of [Fe(CN)₅NO]^2– remains monodentate and the bond angle of Fe^II—N—O is 180.0°. The variable temperature magnetic susceptibilities, measured in the 5–300 K range, show weak intralayer antiferromagnetic interactions in both complexes with the intramolecular iron(III)iron(III) exchange integrals of –0.017 cm^–1 for (1) and –0.020 cm^–1 for (2), respectively.     

Synthesis and Spectroscopic Characterization of Silver(I) Complexes of Selenones

Silver(I) complexes of selenones, [LAgNO₃] and [AgL₂]NO₃ (where L is imidazolidine-2-selenone or diazinane-2-selenone and their derivatives) have been prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹⁰⁷Ag) spectroscopy. An upfield shift in the C=Se resonance of selenones in ¹³C NMR and a downfield shift in N-H resonance in ¹H NMR are consistent with selenium coordination to silver(I). In ¹⁰⁷Ag NMR, the AgNO₃signal is deshielded by 450-650 ppm on coordination to selenones. Greater upfield shifts in ¹³C NMR were observed for [LAgNO₃] compared to [AgL₂]NO₃complexes, whereas the opposite trend was observed for ¹H and¹⁰⁷Ag NMR chemical shifts.     

A novel cyano complex of tungsten(IV) with 2, 2′-bipyridyl

Summary (bpyH)₃(H₃O)[W(CN)₈]·H₂O reacts at high temperature to give the ionic species [W(bpy)(CN)₆]^2–. Tetraphenylphosphonium and tetraphenylarsonium salts were isolated as solids whereas the acid and its alkali metal salts were investigated in solution. The new complexes were characterized by u.v. and visible, i.r. and e.s.r. spectrometry, t.g. and d.t. analysis. The intensively coloured salts exhibit solvent—dependent absorption bands at low energy assigned to Wbpy transitions.     

Crystallization method controlled trinuclear or ion-pair Manganese(III)-porphyrin-based heterobimetallic complexes: Synthesis,spectra characterization,and crystal structure

Cyanide-bridged trinuclear heterometallic Ag(I)-Mn(III) complex {[Mn(TClPP)(H₂O)]₂[Ag(CN)₂]}₂ · 2Br · 2C₃H₆O · 3H₂O (I) and ion-pair complex {[Mn(TClPP)(CH₃OH)₂][Ag(CN)₂]} · 0.5H₂O (II) have been synthesized with [Mn(TClTPP)(H₂O)₂]Br (H₂TClTPP = meso-tetra(4-chlorophenyl)porphyrin) as assembling segment and K[Ag(CN)₂] as building block by using different crystallization method. These two complexes have been characterized by elemental analysis, IR spectroscopy and X-ray structure determination. In the trinuclear complex I, [Ag(CN)₂]^? as bidentate ligand coordinates with the two central Mn(III) atom of [Mn(TClPP)(H₂O)₂]⁺ through its two trans cyanide groups to form the complex cation of [Mn(TClPP)(H₂O)]₂[Ag(CN)₂]⁺, which further constructs the neutral complexes with the help of one Br^? as balanced anion. For the ion-pair complex II composed by free [Mn(TClPP)(CH₃OH)₂]⁺ cation and free [Ag(CN)2]^? anion, it can be linked into one-dimensional supramolecular structure with the dependence of the intermolecular O-H...N and O-H...O hydrogen bond interactions.     

The chemistry of pyridinethiols and related ligands,Part 9. Synthesis,spectroscopy and crystal structure of sulphur bridged dimeric [{η3-(O-μ-S)-1-oxopyridine-2-thione}(triphenylphosp hine)silver(I)]

Reaction of 1-hydroxypyridine-2-thione (HpyOS) in CHCl3 with Ag2CO3 suspended in CHCl3 under magnetic stirring followed by addition of PPh3 yields a product of stoichiometry: Ag(pyOS)(PPh3). The compound adopts a dimeric structure [Ag(pyOS)(PPh3)]2 (1) where each Ag atom acquires a distorted tetrahedral geometry by co-ordinating to one oxygen, two sulphur and one phosphorus atoms. The Ag2S2 core forms a parallelogram [Ag—S 2.507(1), 2.822(1)Å] with Ag—S—Ag and S—Ag—S angles of 74.8(1) and 105.2(1)°, respectively.     

Synthesis,crystal structure and magnetic properties of a two-dimensional mixed-valence assembly [Fe(salen)]2[Fe(CN)5NO]

A cyanide-bridged Fe^III–Fe^II mixed-valence assembly, [Fe^III(salen)]₂[Fe^II(CN)₅NO] [salen = N,N-ethylenebis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na₂[Fe(CN)₅NO] · 2H₂O and a MeOH solution of [Fe(salen)NO₃] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—Fe^II—CN—Fe^III—NC—]₄ units with dimensions: Fe^II—C = 1.942(7) Å, C—N = 1.139(9) Å, Fe^III—N = 2.173(6) Å, Fe^II—C—N = 178.0(6)°, Fe^III—N—C = 163.4(6)°. The Fe^II—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe^III–Fe^III exchange integral of –0.033 cm^–1.     

Synthesis,crystal structure,and properties of [Cu(LH)]2[M(mnt)2] [M = Ni or Cu; H2L = 3,3′-(1,3-propanediyldinitrilo)-bis(2-butanone oxime); mnt2− = maleonitriledithiolate] complexes containing bridging cyano groups

Interesting complexes containing a mnt^2– bridge, based on the reaction of [M(mnt)₂]^2– [M = Ni or Cu] with [Cu(LH)]⁺, have been prepared and characterized by e.s.m.s., i.r and u.v–vis. spectroscopic techniques and by electrochemistry. The complexes show weak antiferromagnetic interactions between magnetic centers. The X-ray analysis of the molecular structure of [Cu(LH)]₂[Ni(mnt)₂] has been completed. It structurally features the CN group of mnt^2– which can act as a bridging ligand between two transition metals.     

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(-NC)}₂Ru(bpy)₂](PF₆)₂ and [{(N—N)-(PPh₃)Cu(-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)(-CN)Ru^(II) complexes.     

A new convenient method for the synthesis of mixed-ligand β-diketonato Tc(III) complexes

A new convenient method has been proposed to synthesize mixed-ligand -diketonato Tc(III) complexes, using the ligand exchange reaction [Tc(acac)₂(CH₃CN)₂]⁺+L^–[Tc(acac)₂L]+ +2CH₃CN where L is bza, dpm or dbm. The yield was about 30–40%. UV-visible and IR spectra of these complexes were measured. Characteristic features of the compounds were compared with those of the corresponding complexes of ruthenium.     

Silver(I) complexes of thiourea

Ag^I complexes of thiourea (tu) having the general formula Ag(tu) _x NO₃ (x = 1–4) have been prepared and characterized by elemental analyses, i.r. and n.m.r. (¹H, ¹³C, ¹⁵N and ¹⁰⁷Ag) spectroscopy. Separate i.r. bands were observed for terminal and bridging tu ligands in the complexes. The Ag(tu)NO₃ complex is assumed to be polymeric with all tu groups in the bridging mode. A consistent upfield shift in the ¹³C-n.m.r. chemical shift is observed as the number of tu groups attached to Ag^I increases, whereas the opposite trend is observed for ¹H, ¹⁵N and ¹⁰⁷Ag chemical shifts.     

Mixed ligand transition metal complexes of tertiary phosphines and 5-phenyl-l,3,4-oxadiazole-2-thione

Transition metal complexes containing two types of ligands: 5-phenyl-1,3,4-oxadiazole-2-thione ion (L) and tertiary phosphines, have been prepared. The complexes, [ML₂A₂] [M = Pd or Pt; A = PPh₃ or Ph₂PCH₂CH₂P(O)Ph₂] and [ML₂B] (M = Co, Ni, Pd or Pt; B = Ph₂PCH₂PPh₂ or Ph₂PCH₂CH₂PPh₂), were characterized by elemental analysis, molar conductance, i.r., u.v.–vis., ³¹P-n.m.r., magnetic susceptibility measurements and mass spectra.     

The crystal structure of caesium tetracyanodioxoosmate(VI) Cs2[OsO2(CN)4]

Summary The crystal structure of the caesium salt of [OsO₂(CN)₄]^2– has been determined from three-dimensional x-ray diffraction data. The orange crystals are monoclinic, space group C2/m with a=12.125(2), b=8.284(1), c=5.457(1) Å, =102.01(1)° with two molecules per unit cell. The final R value using 778 observed reflections and anisotropic thermal parameters for all atoms was 0.028. The [OsO₂(CN)₄]^2– ion has an octahedral geometry. Bond distances: Os=O=1.750(8)Å and Os–C=2.093(9)Å.     

Oxo-tricyano complexes of molybdenum(IV) and tungsten(IV) with bidentate Schiff bases

Summary The reaction of [M(CN)₄O(OH₂)]^2– (M = Mo or W) with 2-acetylpyridine and methyl-or butyl-amine in a water-MeOH mixture gave [M(CN)₃O(L-L)]^- (L-L= Schiff base ligand), isolated as [AsPh₄]⁺ salts. The complexes have been characterized by elemental analysis, and electronic, i.r. and¹H-n.m.r. spectroscopy. The Schiff base ligands complex in a bidentate manner through the two nitrogen atoms giving mixed-ligand compounds similarly to 2,2-bipyridyl or 1,10-phenanthroline.On leave from the Faculty of Chemistry, Jagiellonian University, Kraków.     

Dinuclear complexes with a μ-cyano ligand. Part XI(1). Synthesis and characterization of several derivatives ofcis-[Co(NH3)(en)2(H2O)]3+

Summary The new complex double saltscw-[Co(NH₃)(en)₂(H₂O)]₂ [M(CN)₄]₃ (en = ethylenediamine; M = Ni, Pd or Pt),cis-[Co(NH₃(en)₂(H₂O)]₂[FeNO(CN)₅]₃ andcis-[Co(NH₃)(en)₂(H₂O)][Co(CN)₆] have been synthesized and by anation in the solid state the corresponding new dinuclear complexes with a cyano bridgecis- ortrans-[(NH₃)(en)₂Co-NC-M(CN)₃]₂ [M(CN)₄] (M = Ni, Pd or Pt);cis-, trans-[(NH₃)(en)₂Co-NC-FeNO(CN)₄]₂[FeNO(CN)₅] andcis-[(NH₃)(en)₂Co-NC-Co(CN)₅ have been prepared. The complexes have been characterized by chemical analysis, t.g. measurements, and by i.r. and electronic spectroscopy. With [Ni(CN)₄][^2– and [Co(CN)in]₆ ^3– only thecis-isomer is produced; with [Pd(CN)₄]^2–, [Pt(CN)₄]^2– and [FeNO(CN)₅]^2– thetrans- isomer is the dominant species. The dinuclear complex derived from [Pt(CN)₄]^2– shows strong Pt-Pt interactions both in the solid state and in solution.     

Copper(I) complexes of nitrogen-sulphur ligands. 1-Phenyl-4,6-dimethylpyrimidine-2-thione and its protonated form as ligands in copper(I) complexes. Chemical,spectroscopic, conductivity and polarographic studies

Summary 1-Phenyl-4,6-dimethylpyrimidine-2-thione (L) and its protonated cation 1-phenyl-4,6-dimethyl pyrimidinium-2-thione , have been employed to prepare the following copper(I) complexes: CuXL (X=Cl, Br, I, ClO₄ or BF₄), (CuX)₃L₂ (X=Cl, Br, I or SCN), (CuX)₂L₅ (X= ClO₄ or BF₄) and the zwitterionic species CuXY(LH) X=Y=Cl, Br or I; X=Br; Y=Cl; X=I; Y=Br). Chemical analysis, conductivity, and near-and far-i.r. spectroscopic data are presented and the chemical relationships between them discussed in terms of postulated dinuclear or polynuclear species for the complexes. Metalligand vibrations suggest that the neutral ligand is N, S-bidentate in its copper(I) complexes as well as S-coordinat for the cation in the zwitterionic compounds. Diagnostic i.r. bands frequencies of counterions and (Cu–X) modes indicate the coordinating character of Cl^–, Br^–, I^–, SCN^– and of ClO ₄ ^– , BF ₄ ^– (in CuXL) anions. For the chloro-complexes CuClL and (CuCl)₃L₂, salt-like species of the [CuL₂][CuCl₂] and [{Cu₂L₂Cl}_n] [CuCl₂]_n type respectively, are proposed. The polarographic data for the perchlorate complexes have shown that in dimethylformamide (DMF) solution, the prevailing species are CuClO₄L, CuClO₄L₂ and (CuClO₄)₂L₅; their overall stability constants were determined.     

Mixed ligand palladium(II) complexes of oxalate and malonate with vitamin-B6 molecules: synthesis,crystal structure and kinetics

The synthesis of six mononuclear palladium complexes of general formula [Pd(ox)/(mal)L₂] and [Pd(ox)/(mal)L] (ox = oxalate, mal = malonate, both L and L are vitamin-B₆ molecules (I), L = pyridoxine, pyridoxal and L = pyridoxamine) has been achieved. The structures of these compounds were established by elemental analysis, i.r. and ¹³C-n.m.r. [Pd(oxalate)(pyridoxine)₂] was analyzed by single crystal X-ray diffraction. It exhibits square planar coordination with bond lengths 2.015 (2) Å for Pd—N and 2.010 (2) Å for Pd—O. The interaction of [Pd(ox)₂]^2– and [Pd(mal)₂]^2– with L has been followed kinetically in order to look into the nature of products and the mechanism of formation under the conditions [Pd^II-chelate] [L] and [L].     

Mixed-ligand complexes of gold(I) and silver(I) with heterocyclic thiones

Summary Novel mixed-ligand complexes of Ag¹ and Au¹ containing triphenylphosphine (TPP) and heterocyclic thiones, of general formula [TPP–M–L]Cl and [(TPP)₂–M–L]Cl, where L=imidazolidine-2-thione (Imt), 1,3-diazinine-2-thione (Diaz) or N-isopropylimidazolidine-2-thione (iPrImt) have been prepared. The spectroscopic data are consistent with S-donation in all complexes. The magnitude of high-field shift in carbon-13 n.m.r. of the thioureide carbon on complexation is interpreted in terms of coordination geometry around the metal atoms. The mixed-ligand complexes are structurally similar to some of the commonly used antiarthritic Au¹ drugs and are thus potentially useful in chemotherapy.     

Mixed-ligand complexes of copper(I) with heterocyclic thiones

Summary Novel mixed-ligand copper(I) complexes of general formula [TPP–Cu–(L)Cl] or [TPPhos–Cu–(L)Cl], where TPP=triphenylphosphine, TPPhos=triphenylphosphate and L=imidazolidine-2-thione [Imt],N-propylimidazolidice-2-thione [PrImt],N-i-propylimidazolidine-2-thione [iPrImt], and 1,3-diazinine-2-thione [Diaz] and bis coniplexes of formula [(L)₂CuCl] where L=[PrImt] and [iPrImt] have been prepared and characterized by electronic, vibrational and n.m.r. spectroscopy. The spectral data are consistent with S-donation of thiones. The magnitude of upfield shift in¹³Cn.m.r. of the thionreide carbon on complexation has been interpreted in terms of coordination geometry around the metal stoms. X-ray structure analysis agrees with the conclusions from the spectroscopic measurements. The structure of [(PrImt)₂CuCl] revealed three-coordinated copper(I) with crystal data:a=14.106(4),b=14.380(2),c=19.024(3) A, =108.8(2)°,z=8 and space group P2/c.