A new uninegative ligand, tris-(diphenylthiophosphinyl)methanide

The reaction of tris-(diphenylthiophosphinyl)methane, [(C₆H₅)₂P(S)]₃CH, with mercury(II) halides produces complexes of the type [(C₆H₅)₂P(S)]₃CHgX, where X is Cl, Br and I.     

Far-IR spectra of charge-transfer complexes between IX (X = Cl,Br or I) and trans-1,2-bis(4-pyridyl)ethylene, 1,2-bis(4-pyridyl)ethane and 4,4′-

Far-IR spectra of charge-transfer complexes of trans-1,2-bis(4-pyridyl)ethylene (Bpe), 1,2-bis(4-pyridyl)ethane (Bpa) and 4,4′-bipyridyl (4,4′-     

Polarography of o- and p-nitrophenyl acetic acids

Polarography of o- and p-nitrophenyl acetic acids has been carried out in aqueous buffers (pH 2.0 to 12.0) of constant ionic strength (1.0 M) at 30 ± 0.5 °C. The nitro group underwent a diffusion-controlled reduction (6e) over the whole pH range. The number of electrons involved in the reduction was found by incorporating the values of diffusion coefficients, obtained by using a McBain-Dawson cell, into the Ilkovic equation. Koutecky's method has been used to compute the kinetic parameters (αn_aand ?log k^o_f,h) for the reduction of the nitro group and a reduction mechanism is proposed.     

The mercuration of ortho- and meta-carboranes

The mercuration of ortho- and meta-carboranes is described. This mercuration proceeds at the boron atom of the icosahedral at position 9.     

Magnetic and spectral studies on N-(thiophene-2-carboxamido)salicylaldimine complexes of some bivalent 3d metal ions

Metal(II) complexes of N-(thiophene-2-carboxamido)salicylaldimine (H₂TCS) of types M(H₂TCS)₂Cl₂ [M = Ni, Cu and Zn], M(HTCS)Cl [M = Co, Ni and Cu], M(HTCS)₂ [M = Mn, Fe, Co, Ni, Cu and Zn], M(TCS)·xH₂O [M = Mn, Co and Ni, x = 2; M = Cu, x = 0], Ni(TCS)py₂ and Cu(TCS)py have been prepared. Elemental analyses, molar conductance, magnetic moment, electronic, IR and ESR spectral studies have been used to characterize these complexes. The different modes of chelation of the ligand and the stereochemistry of the complexes are discussed.     

Reaction of trans-[Co(en)2(SO3)(H2O)]+ with imidazole and containing ligands

trans-[Co(en)₂(SO₃)(H₂O)]⁺ reacts with imidazole (ImH) and imidazole containing ligands (L) to form trans-[Co(en)₂(SO₃)L]⁺ in the pH range 6.0–9.0. The complex seems to react both in the hydroxy and in the aquo form. The rate constant for the reaction of imidazole with the aquo form is 6.0±0.7 and 4±1M^?1s^?1 for the reaction with the hydroxy form at 25°C. The apparent equilibrium constant for formation of the imidazole complex at pH 7 is consistent with the value of 3 x 10² measured previously. Appreciable amounts of complex form only in the pH 6–9 range. Above pH 9 NMR spectra show that even the immediate products are different. In aged solutions at all pHs other products form.     

The preparation of cis- and trans-[PtH(C6Cl5)(PEt3)2 and a study of the “hydride-donor capacity” of the complexes trans- [PtH(C6X5(PEt3)2] (X = F and Cl)

The preparations of cis- and trans-[PtH(C₆Cl₅)(PEt₃)₂] by thermal decomposition of cis- and trans-[Pt(OCHO)(C₆Cl₅)(PEt₃)₂], respectively, are reported. Also described are cis- and trans-[Pt(SnCl₃)(C₆Cl₅)(PEt₃)₂], obtained by treating SnCl₂ with cis- and trans-[PtCl(C₆,Cl₅)(PEt₃)₂], respectively. It is shown that while trans- [PtH(C₆Cl₅)(PEt₃)₂] does not form hydride-bridged complexes in the presence of trans-(PtH(MeOH)(PEt₃)₂]⁺, the corresponding complex trans-[PtH(C₆)(PEt₃)₂] reacts with the same solvento complex, in methanol, giving labile [(PEt₃)₂HPt(-μH)Pt(C₆F₅)(PEt₃)₂]⁺.     

Rhodium(I) catalysis of cycloprop[a]acenaphthylene isomerizations

Cycloprop [a] acenaphthylene was found to rearrange to phenalene in the presence of rhodium dicarbonyl chloride dimer. Deuterium labeling of this molecule at C(7) (both exo and endo), at C(8), at C(7) (exo) and C(8) and at C(7) (exo), C(8), and C(8') indicated that the C(7) (exo) deuterium was migrating stereospecifically. Furthermore, all of the isotopic label present in the cycloprop[a]acenaphthylene was found statistically distributed over positions 1, 3, 4, 6, 7, and 9 of the phenalene product. Control experiments established the need of the catalyst, the inability to achieve rearrangement of the exo-7-methyl derivative, and the susceptibility of a monodeuterated phenalene for extensive isotopic scrambling in its own right when exposed to rhodium(I). These results have been interpreted on the basis of oxidative addition by rhodium(I) into the central bond of cycloprop[a]acenaphthylene from above the “flap”, followed by shifting of the C(7) (exo) hydrogen (or deuterium) to give a η³-allylrhodim-(III) complex. The experimental data further support a mechanism involving subsequent rearrangement of this intermediate around the periphery of the phenalene ring. This process which is otherwise degenerate is thought to be facilitated by the special electronic features of the phenalenyl system.     

Carbonyl-organocobalt(I) and -(II) complexes

Passage of CO through solutions of complexes (C₆F₅)₂CoL₂ gives carbonyl derivatives (C₆F₅)₂CoL₂(CO) (L₂ = 2 PEt₃, 2 P-n-Bu₃, 2 PPh₃, Ph₂PCH₂CH₃PPh₂). The properties of these compounds are described.The compounds are also produced by treating solutions of (C₆F₅)₂Co-(dioxane)₂ with CO, but a simultaneous reduction to (C₆F₅)Co(CO)₄ takes place. Treatment of the latter complex with monodentate ligands gives substitution products (C₆F₅)Co(CO)₃L (L = PEt₃, P-n-Bu₃, PPh₃) all of which are monomeric, whereas the addition of Ph₂PCH₂CH₂PPh₂ gives the dimer (C₆F₅)(CO)₂CoLLCo(CO)₂(C₆F₅). The properties of these compounds are discussed.     

The preparation and synthetic value of fac-[M(CO)3(NCR)3]+ cations (M  Mn or Re; R  Et,Pr OR PhCH2)

Treatment of MBr(CO)₅ (M = Mn or Re) with AgClO₄ and an organonitrile in a suitable solvents affords the complexes fac-[M(CO)₃(NCR)₃][ClO₄], (R = Et, Pr or PhCH₂). The use of these complexes as synthetic precursors has been illustrated by the preparation of fac-[M(CO)₃L₃][ClO₄], (M = Mn, L = NH₃ or L₃ = dien; M = Re, L₃ = triphos). Pure fac-[Re(CO)₃(NH₃)₃][ClO₄] could not be prepared using this nitrile displacement route, but may be isolated, as the PF₆^? salt, from the reaction of [Re(CO)₃(toluene)][PF₆] and ammonia in chloroform.     

Rhodium(I) and rhodium(III) arene complexes with N-carbazolyltriphenylphosphinegold(I) and other polycyclic arene ligands

The new heteronuclear arene complexes [(COD)Rh(μ-cbz)AuPPh₃]ClO₄, [{(COD)Rh}₂(μ-cbz)AuPPh₃](ClO₄)₂, [(C₅Me₅)Rh(μ-cbz)AuPPh₃](ClO₄)₂ and [{C₅Me₅) Rh}₂(μ-cbz)AuPPh₃](ClO₄)₄ (COD = 1,5-cyclooctadiene, cbz = carbazolyl), and the mononuclear arene complexes [(COD)Rh(arene)]ClO₄ (arene = tetralin, biphenyl, fluorene, indene, 9,10-dihydroanthracene or carbazole) have been prepared by reaction of the acetone solvated complexes [(COD)Rh(Me₂CO)_x]ClO₄ or [(C₅Me₅)Rh(Me₂CO)₃](ClO₄)₂ with (cbz)AuPPh₃ or the appropriate polycyclic arene ligand.     

Copper(I) and silver(I) complexes of 2-amino-1,3,4-thiadiazole and 2-ethylamino-1,3,4-thiadiazole

The following copper(I) and silver(I) complexes of 2-amino-1,3,4-thiadiazole (atz) and 2-ethylamino-1,3,4-thiadiazole (eatz) have been prepared and studied by conductometric, IR and Raman methods: CuXL(X = Cl, Br, I; L = atz, eatz), CuXL₃(X = ClO₄, NO₃; L = atz, eatz), AgClO₄·1.5atz·1/3 EtOH, AgNO₃·2.5atz, AgClO₄·3eatz, AgNO₃·eatz. The ligands are bonded through the amine nitrogen atoms with ν(MN) bands in the 520–410 cm^?1 region. The CuXL complexes have a trigonal (N, 2X_b) coordination with a probable weaker axial interaction. The CuXL₃ and AgCIO₄·3eatz complexes probably have a trigonal pyramidal (3N,O) coordination. In the atz complexes of silver perchlorate and nitrate some ligand molecules are bridging. The AgNO₃·2.5atz complex is likely to have a dimeric structure with tetrahedral coordination of the silver ion.     

The formation and crystal and molecular structures of hexa(μ-organothiolato)tetracuprate(I) cage dianions: bis-(tetramethylammonium)hexa-(μ-methanethiolato)tetracuprate(I) and two polymorphs of bis(tetramethylammonium)hexa-(μ-benzenethiolato)-tetracuprate(I)

X-Ray analysis shows that the crystalline compounds (Me₄N)₂[Cu₄(SMe)₆] (1), (Me₄N)₂[Cu₄(SPh)₆] (2) and (Me₄N)₂[Cu₄(SPh)₆]EtOH (3) all contain the [tetrahedro-Cu^I₄-octahedro-(SR)₆]^2? molecular cage. Very well developed pale yellow crystals of (2) and (3) can be obtained directly from a mixture of copper(II) salt and excess benzenethiol with tertiary amine in alcohol. The substituents R of the [Cu₄(SR)₆]^2? cage remove the high symmetry of the Cu₄S₆ core, and allow three configurational isomers for the cage. All known instances of this cage structure occur as the isomer which minimises the number of close contacts of substituents over the surface of the cage. Despite this, there remain intra-cage repulsive interactions between substituents, greater for RPh than for RMe, which cause distortions primarily in the SCuS angles which range from 105–144°. CuS distances are coupled, apparently electronically, to opposite SCuS angles. The stereo-chemical analysis is extended to all known Cu₄(SR)₆ cages, and to alternative cage structures.     

Spectroscopic and structural properties of homonuclear Fe(II) pyrazine-bridged polymeric complexes [Fe(pyrazine)2X2]n. (X = Cl,Br or I)

The reactions of FeX₂ (X = Cl, Br or I) with pyrazine (pyz) yield the Fe(pyz)₂X₂ compounds. Examination of IR and Raman spectra in the medium- and far-IR region as well as studies of electronic and Mössbauer spectra suggests that the complexes contain six-coordinate high-spin Fe(II) in the FeN₄X₂ chromophore. The complexes have a polymeric pseudo-octahedral pyz-bridged structure. The magnetic moments are independent of temperature and low-temperature magnetic measurements do not indicate any magnetic ordering above 4.2 K in these compounds. The π-acceptor properties of pyz are reflected both in the electronic spectra evaluated in terms of the angular overlap model and the Mössbauer parameters.     

Spectroscopic studies of 4-substituted pyridinium 2-pyridylcarbonylmethylide-rhodium(I) complexes and x-ray molecular structure of (1,5-cyclooctadiene) (4-methylpyridinium 2-pyridylcarbonylmethylide)rhodium(I) perchlorate

(1,5-Cyclooctadiene) (4-substituted pyridinium 2-pyridylcarbonylmethylide)- rhodium(I) perchlorates, [Rh(COD)(C₅H₄NC(O)C?H₊C₅H₄X-4)]ClO₄ [COD = 1,5-cyclooctadiene; X = CH₃C(O), CH₃OC(O), C₆H₅, CH₃, and H], have been prepared. They are shown to have the geometry with coordination by the pyridyl nitrogen and carbonyl oxygen atoms of the ylide ligands and to exhibit intramolecular rearrangement of coordinated COD in chloroform, methanol, and dimethyl sulphoxide based on IR and ¹H NMR spectroscopies. Although the ylides have exhibited fluorescence bands due to an intramolecular charge-transfer transition and phosphorescence bands due to a carbonyl ³(n?π^*) transition, the complexes have given emission bands due to the metal-to-ylide ligand charge-transfer transition. A.single crystal X-ray crystal structure has been determined for [Rh(COD)(C₅H₄NC(O)C?H₊C₅H₄CH₃-4)]ClO₄. The crystals are monoclinic, space group P2₁/n with cell dimensions a = 14.887(3), b = 20.274(4), c = 6.966(1) Å, β = 96.13(1)°, and Z = 4. The structure has been refined by a block-diagonal least-squares method to final R = 0.060 for 2997 independent reflections with |F_o| > 3σ(F). The ylide carbon-pyridinium nitrogen bond distance is 1.420(10) Å. The bonded distances from rhodium to the midpoints of the double bonds of COD are 1.982(11) and 2.014(12) Å.     

Preparation,crystal and molecular structure of,and NMR parameters for,the exopolyhedral heterocyclic platinaundecaborane [μ-2,7-(SCSNEt2)-7-(PMe2Ph)-NIDO-7-PtB10H11]

The compound [μ-2,7-(SCSNEt₂)-7-(PMe₂Ph)-nido-7-PtB₁₀H₁₁] has been obtained in a yield of 52% from the reaction of [7,7-(PMe₂Ph)-nido-7-PtB₁₀H₁₂] and [AuBr₂(S₂CNEt₂)], and identified by single crystal X-ray diffraction analysis and multi-element single and double resonance NMR spectroscopy. The yellow-orange compound crystallizes in the monoclinic space group P2₁/n with a 1179.2(2), b = 1244.9(5), c = 1641.4(2) pm, β = 95.45(1)°, Z = 4, and the structure (R 0.0209, R_w = 0.0211 for 3719 observed reflections) is that of a nido-7-platinaundecaborane with an exopolyhedral N,N-diethyldithiocarbamate ligand bridging the Pt(7) and B(2) positions to give a $\text{-Pt-B-C-S-}$ five-membered ring. The tetrahapto platinum-to-borane bonding has a considerable twist distortion relative to other nido-7-platinaundecaboranes which do not possess this cyclic feature. The NMR parameters exhibit no anomalies and are consistent with the crystal molecular structure. A plot of δ(¹¹B) vs δ(¹H) for directly bound exo-terminal hydrogen atoms shows good correlation with the slope 16 : 1.     

Structure of di-μ-N-Phenylanthranilato-di-1, 5-cyclooctadiene dirhodium(I)

The reaction of [RhCl(COD)]₂ (COD = 1,5-cyclooctadiene) with sodium N-phenylanthranilate leads to the formation of the new crystalline rhodium(I) complex [RhFA(COD)]₂ (FA = N-phenylanthranilate anion). The compound is a dimer with two N-phenylanthranilate ions bridging and COD ligands terminally bonded to rhodium with an Rh … Rh distance equal to 3.424(3) Å. Strong intramolecular hydrogen bonding occurs between the hydrogen of the NH group and the closest carbonyl oxygen in the FA ligands. The crystals are monoclinic, space group P2₁/c, with a = 11.246(8), b = 14.999(9), c = 21.82(2) Å, β = 105.11(6)°. The structure was solved by the heavy-atom method and refined by least squares to R = 0.035 for 4260 diffractometer data.     

New biimidazole and bibenzimidazole derivatives: mono and binuclear palladium(II) or platinum(II) complexes and heterobinuclear palladium(II)-rhodium(I) or platinum(II)-rhodium(I) complexes

Novel neutral biimidazolate or bibenzimidazolate palladium(II) and platinum(II) complexes of the type M(NN)₂(dpe) [M = Pd, Pt; (NN)₂^2? = BiIm^2?, BiBzIm^2?. dpe = 1,2-bis(diphenylphosphino) ethane] have been obtained by reacting MCl₂(dpe) with TI₂(NN)₂. Complexes M(NN)₂(dpe) which are Lewis bases react with HClO₄ or [M(dpe)(Me₂CO)₂](ClO₄)₂ to yield, respectively, mononuclear cationic complexes of general formula [M{H₂(NN)₂](dpe) (M = Pd, Pt; H₂(NN)₂ = H₂BiIm, H₂BiBzIm) and homobinuclear palladium(II) or platinum(II) cationic complexes of the type [M₂{μ - (NN)₂}(dpe)₂](ClO₄)₂. Reactions of M(BiBzIm)(dpe) with [Rh(COD) (Me₂CO)_X](ClO₄) render similar heterobinuclear palladium(II)-rhodium(I) and platinum(II)-rhodium(I) cationic complexes, of general formula [(dpe)M(μ-BiBzIm)Rh(COD)](ClO₄) (M = Pd, Pt; COD = 1,5-cyclooctadiene). Di- and mono-carbonyl derivatives [(dpe)M(μ-BiBzIm)Rh(CO)L](ClO₄) (M = Pd, Pt; L = CO, PPh₃) have also been prepared. The structures of the resulting complexes have been elucidated by conductance studies and IR spectroscopy.     

A new copper(I) thiocyanato thiocyanogen complex

The reaction between Cu²⁺ and SCN^?, in glacial acetic acid at a Cu/SCN ratio, of 1:4, gave a dark red solution that exhibited an absorption band at 496 nm. The colour of the freshly prepared solution was bleached by water with concomitant production of SO₄^2? ion. On standing, the stability of the colour towards water is increased and the position of the absorption band shifts to a higher wavelength. It is inferred that the thiocyanogen produced on oxidation of SCN^? by Cu²⁺ is stable in the non-aqueous medium and is coordinated together with SCN^? in a Cu(I) complex. The bleaching action of water is attributed to the hydrolysis of thiocyanogen, mainly to SO₄^2?. The presence of thiocyanogen enhanced polymerization and subsequent deposition of an orange-brown solid complex. On the basis of chemical, spectral, and thermal analyses the formula K[Cu(SCN)₂(NCS—SCN)], is assigned to the new compound.     

The formation and structural chemistry of the hexa(μ-t-butylthiolato) pentacuprate(I) cage anion with triethylammonium and tetraethylammonium cations

Yellow (Et₄N)[Cu₅(SBu^t)₆] crystallises from solutions prepared from Cu(II), Bu^tSH, Et₃N and Et₄NBr in acetone/ethanol, while (Et₃NH)[Cu₅(SBu^t)₆] crystallises from solutions of CuSBu^t and Bu^tSH in Et₃N. Crystal structure determinations reveal that both compounds contain the molecular cage [Cu₅(μ-SBu^t)₆]^?, in which two copper atoms are three-coordinate (Cu_trig), three copper atoms are two-coordinate (Cu_dig), and all thiolate ligands are doubly-bridging. The polyhedral stereochemistry of the core is trigonalbipyramido-Cu₅-trigonal antiprismo-S₆. The complete [Cu₅(μ-SBu^t)₆]^? cage in the Et₄N⁺ compound closely approaches D₃ symmetry, but in the Et₃NH⁺ compound one SBu^t ligand is inverted at the sulphur bridge, causing angular distortions in the cage.Two structural features, the antiprismatic twist of the S₆ polyhedron and the bending of Cu_dig towards the cage centroid (S-Cu_dig-S = 171(1)°), provide evidence for weak Cu-Cu attractive interactions within the cage. Infrared data are discussed. Crystal data: (Et₄N)[Cu₅(SBu^t)₆], C₃₂H₇₄Cu₅NS₆, a = 45.500 (3), b = 11.805(1), c = 20.168(2) Å, β = 117.81 (1)°, C2/c, Z = 8, R = 0.078 (2953 observed F); (Et₃NH)[Cu₅(SBu^t)₆], C₃₀H₇₀Cu₅NS₆, a = 10.519(1), b = 21.457(1), c = 20.065(1), β = 95.11(1), P2₁/c, Z = 4, R = 0.072 (3093 observed F). (Et₄N)[Ag₅(SBu^t)₆] is isostructural with (Et₄N)[Cu₅(SBu^t)₆].