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′-     

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]⁺.     

pentahapto- UND trihapto- cycloheptadienylkobalt(I)-komplexe

Treatment of [CoH(N₂)(PPh₃)₃] with cycloheptatriene in diethyl ether affords [Co(1—5-η-C₇H₉)(PPh₃)₂] (I). An etherical solution of (I) reacts with CO at room temperature and under normal pressure to yield the carbonyl complex [Co(1—3-η-C₇H₉)(CO)₂(PPh₃)] (II). These compounds are characterized by their PMR and IR spectra.     

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.     

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.     

The isomerization of cis,trans-1,5-cyclodecadiene by RhCl3 · 3H2O in ethanol

The isomerization of cis,cis-1,6-cyclodecadiene to cis,trans-1,5-; and cis,cis-1,5-cyclodecadiene in the presence of their rhodium complexes seems to indicate an isomerization for which no thermal conversion has been reported. Evidences are presented for the functioning of ethanol as a hydride source in these polymerizations.     

1,2- and 1,7-Dicarba-closo-dodecarborane(12)platinum(II) complexes formed through metal—carbon σ bonds: cis- and trans-monohydrido derivatives

New neutral platinum(II) monohydridocarborane complexes of general formula cis- and trans-L₂PtH(σ-carb), where L = (C₂H₅)₃P, (C₆H₅)₃P, (C₆H₅)₂(CH₃)P, (C₆H₅)(CH₃)₂P and carb = 2-R-1,2- or 7-R-1,7-B₁₀C₂H₁₀^? (R = H, CH₃, C₆H₅), have been prepared. The configurations of the complexes obtained have been assigned by ¹H NMR spectroscopy. The _cis-monohydridocarborane complexes here reported are the first examples of neutral _cis-monohydrido derivates of platinum(II) containing platinum—carbon σ bonds. ¹H NMR chemical shifts and coupling constants of the prepared complexes are also reported, and used in a tentative evaluation of the _trans-influence of the carbonage ligands.     

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.     

Synthesis of 1,2-ethanediylbis(diphenyl-phosphonium)-PH,P′H′ hexachloromolybdate(III) I and nonachlorodimolybdate(III) II. The crystal structure of (dppeH2)3[MoCl6]2·12h2O

Two compounds of the formulae (dppeH₂)₃[MOCl₆]₂ ·12H₂O I and (dppeH₂)₃[Mo₂Cl₉]₂II are described. For compound I, which proved to be active in olefin epoxidation, the crystal structure was determined. The rose-pink crystals are triclinic, space group P$\text{1}$ with a = 13.715(9), b₃ = 14.686(7), c = 12.512(7) Å, α = 109.56(4), β = 97,98(4) and γ = 91.27(5)°, V = 2345 Å, D_m = 1.42 and D_c = 1.44 gcm^?3, Z = 1. Block-diagonal least squares refinement of the structure has led to a final value of the conventional R factor of 0.049 for the 3914 independent reflections with I > 3σ(I). Bond distances are in the range: MoCl 2.439(2)–2.469(2) Å, and PC 1.771(9)–1.806(8) Å.     

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.     

Synthesis and spectroscopic characterization of heterobimetallic (α-alkynyl)iron-cobalt hexacarbonyl complexes, μ-(1-σ, 2-3, η2-R2C-CCR′)][(CO)3Fe-Co(CO)3] and [μ-(1-σ, 2-3, η2-H2C-CCCH2OH)] [(CO)3Fe-Co(CO)2(PPh3)]

The title compounds have been prepared from reactions of Co₂(CO)₆(μ-HOR₂CC₂R′) or Co₂(CO)₆(μ-HOR₂CC₂CR₂OH) complexes with Fe(CO)₅ in acetone. In the latter set of reactions the homobimetallic butatriene compounds, Fe₂(CO)₆-(μ-R₂CCCCR₂), are also obtained. The striking feature of these reactions is the ability of Fe(CO)₅ to dehydroxylate the organic moiety and to replace a Co(CO)₃ unit forming mixed iron-cobalt derivatives. A direct interaction between the iron and the carbon atom, originally bearing the lost -OH group, is evident from the bulk of the spectroscopic data; thus the organic chain acts as an overall 5 electron donor, according to the E.A.N. formalism. The heterobimetallic compounds have been characterized by elemental analysis, mass spectrometry, IR spectroscopy and NMR studies. For the phosphine derivative FeCo(CO)₅(PPh₃)(H₂CC₂OH) a crudely refined X-ray analysis has been performed.     

Potassium trifluoroperoxotitanate(IV) trihydrate,K[Ti(O2)F3] · 3H2O

Potassium trifluoroperoxotitanate(IV) trihydrate, K[Ti(O₂)F₃] · 3H₂O, with the peroxide (O₂^2?) being bonded to the Ti(IV) centre in a triangular bidentate manner (C_2ν) as evidenced from the IR and laser Raman spectroscopic studies, has been synthesised from the reaction of a solution of TiO₂in 40% HF with an excess of 30% H₂O₂ and KOH, followed by the addition of aqueous HF to adjust the pH of the reaction solution between 8 and 9.     

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.     

Trans-1,2-dithiooxalate as bridging ligand—II: The X-ray crystal structure of μ-1,2-dithiooxalato-bis[bis(triphenylphosphine)silver(I)]

The X-ray structure of (Ph₃P)₂Ag(SOC₂SO)Ag(PPh₃)₂ shows this complex as the second authentic example containing a bridging trans-1,2-dithiooxalate ligand. The compound crystallizes in the monoclinic space group P2₁/c with a=13.159(2), b=11.895(2), c=20.939(5)Å, β= 101.35(2)° and Z = 2. The structure was solved by Patterson and Fourier methods for 5649 diffractometer data and refined to a final R value of 0.066 for 03545 observed reflections. The dimensions of the dithiooxalate bridge are compared with those of the corresponding trans-dithiooxalate in (Ph₄As)₄ (O₂C₂S₂)₂In(SOC₂SO)In(S₂C₂O₂)₂]. Differences between structures containing bridging trans-dithiooxalate or bridging cis-dithiooxalate, respectively, are discussed.     

1-pyrazolyliridium(I) derivatives; x-ray evidence for monodentate pyrazolato ligands

An X-ray crystal structure determination has shown that trans-(Ph₃P)₂Ir(CO)-(pyrazolato-N), obtained from the chloride and potassium pyrazolate, contains a monodentate azolato ligand.     

Preparation and electrical resistivities of tetrathiafulvalen (TTF) and tetraselenafulvalen salts with the [SnR2Cln]2-n anions (n = 3 or 4: R = Et or Ph) and X-ray crystal structure of [TTF]3[SnEt2Cl4]

Tetrathiafulvalen (TTF) and tetraselenafulvalen (TSF) salts with diorganochloro-stannate anions, [TTF][SnEt₂Cl₃] (1), [TTF]₂[SnPh₂Cl₄] (2), [TTF]₃[SnEt₂Cl₄] (3), [TTF]_3.3[SnPh₂Cl₄] (4), [TSF]₂[SnPh₂Cl₄] (5) and [TSF]_3.3[SnPh₂Cl₄] (6), were prepared by the reactions of [TTF or TSF]₃[BF₄]₂ with SnR₂Cl₂ (R = Et or Ph) in the presence of [Ph₃PCH₂Ph]Cl and by electrocrystallization of TTF or TSF in acetonitrile containing SnR₂Cl₂ and [Ph₃PCH₂Ph]Cl. All the salts behave as semiconductors with electrical resistivities of the order of 10–10⁸ Ω cm as compacted samples at 25°C. Electronic reflectance spectra of the simple salts 1, 2 and 5, show a band due to the dimeric(TTF⁺)₂ or (TSF⁺)₂ unit in the 12,200–12,800-cm^?1 region. The complex salt 3 exhibits a TTF⁺/TTF° charge-transfer (CT) band at 8700 cm^?1, and the remaining complex salts, 4 and 6, both display CT bands between the radical cations and between the radical cation and the neutral donor molecule. The crystal structure of 3 was determined by a single-crystal X-ray diffraction. The tetragonal crystal, space group I4cm, has cell dimensions a = 11.710(3) Å, c = 25.242(7) Å, and Z = 4. The structure was solved by the heavy-atom method and refined to a final R value of 0.082 for 479 independent reflections with >F_° > 3σ(F). TTF molecules exist as trimers, in which a slight lateral shift from the eclipsed TTF overlap occurs, although TTF molecules are arranged with equal spacing between them. The trimer units are located perpendicularly to each other, forming a two-dimensional layer. The [SnEt₂Cl₄]^2? anion is disordered with respect to the two SnEt and two SnCl bonds.     

Mononuclear,three-coordinate metal thiolates: Preparation and crystal structures of [NBun4][Hg(SPh)3] and [NPrn4] [Pb(SPh)3]

Dissolution of HgO or PbO in methanolic solutions of NaSPh yields homogeneous solutions from which highly crystalline [NBuⁿ₄][Hg(SPh)₃] (1) or [NPrⁿ⁴][PB(SPh)₃] (2) can be isolated on addition of appropriate quaternary ammonium salts. 1 crystallizes in monoclinic space group P2₁/a with a = 20.663(7), b = 16.812(6), c = 9.757(3) Å, β = 95.52(2)° and Z = 4. The anion consists of a rare example of trigonal planar coordinated Hg; there are no weaker, intermolecular Hg ... S axial interactions. 2 crystallizes in triclinic space group Pl? with a = 12.689(7), b = 11.255(6), c = 12.046(7) Å, α = 107.93(3), β = 109.64(3), γ = 86.01(3)°, and Z = 2. The anion consists of a trigonal pyramidal coordinated PbS₃ unit. The structures were solved using data collected at approx. ? 160°C and refined to conventional R values of 5.7 and 4.6%, respectively for 1 and 2.     

Synthesis and crystal structure of [N,N′-bis(2,3,5,6-tetrafluorophenyl)-ethane-1,2-diaminato(2-)]dipyridineplatinum(II)

The reaction of PtCl₂en (en = ethane-1,2-diamine) with TlO₂CC₆F₅ in boiling pyridine unexpectedly yielded a polyfluorophenyl-stabilized ethane-1,2-diaminatoplatinum(II) complex, Pt[N(p-HC₆F₄)CH₂]₂(py)₂, 1a, the structure of which has been established by X-ray crystallography.