Compounds Research Articles

THE CORRELATIONS BETWEEN MERCURY SPECIATION AND DISSOLVED ORGANIC MATTER IN THE SEDIMENT OF THE RED SEA

This study addresses the correlations between Hg an d organic matter in recent sediment; samples were collected from the Gulf of Aqaba, Red Sea coasts (o ligotrophic regions) during 2010. In the present st udy TOC analyzer was used to determine Total Organic Carbon (TOC) and Total Nitrogen (TN) concentrations and the total amount of mercury (Hg T) in sediment samples were analyzed by Hydra-C mercury analyzer. The obtained results indicated that, mercury, TOC a nd TN average concentrations in the Red Sea were 85.42 ng g -1 , 5.10 and 4.45 mg L -1 , respectively. The results show that the Total Org anic Carbon (TOC) in sediment represents the sum of various organic comp ounds, which may play a completely different role i n the distribution and accumulation of Hg. slightly c orrelations between the TOC and the concentration o f Hg in the studied sediment arise mainly from the labil e portion of organic matter released. These compoun ds primarily consist of easily degradable algal-derive d lipids and various pigments, which are petrograph ically described as a soluble Organic Matter (OM). The preserved OM in sediment is commonly entrapped within the cell walls of phytoplankton and also appears as a surface coating on sediment particles. The stron g affinity between Hg and OM is due not only to its c hemical reactivity, but also to the physical charac teristic of these labile compounds, which plays the most imp ortant role in the distribution of Hg in sediment.

Landfill Leachate Circulation on Old Waste Pretreatment Performance Prediction with Artificial Neural Networks

Performance of landfill fresh leachate pretreatment by circulation on primitive waste deposits predicted by artificial neural network (ANN) mathematical modeling. Landfill simulation reactor (LSR) for laboratory scale modeling was applied to prepare the old waste and evaluation of pretreatment performance. Concentration of BOD5 and COD in leachate measured as organic compound indicators and NH3 and NH4 concentrations as nitrogen comp ounds. The results indicated that organic matters removal (64%) was higher compare to nitrogen compounds removal (42%). Optimized neural network was constructed with a mean absolute error (MSE) of 30.85 and 6-7-4 structure. The input of model was leachate characteristics and time, while the output was removal performance for organic and nitrogen compounds. The R value of 0.979 from regression analyses indicated there was very good agreement in the trends between forecasted and measured data.

Matching unknown empirical formulas to chemical structure using LC/MS TOF accurate mass and database searching: example of unknown pesticides on tomato skins

Traditionally, the screening of unknown pesticides in food has been accomplished by GC/MS methods using conventional library searching routines. However, many of the new polar and thermally labile pesticides and their degradates are more readily and easily analyzed by LC/MS methods and no searchable libraries currently exist (with the exception of some user libraries, which are limited). Therefore, there is a need for LC/MS approaches to detect unknown non-target pesticides in food. This report develops an identification scheme using a combination of LC/MS time-of-flight (accurate mass) and LC/MS ion trap MS (MS/MS) with searching of empirical formulas generated through accurate mass and a ChemIndex database or Merck Index database. The approach is different than conventional library searching of fragment ions. The concept here consists of four parts. First is the initial detection of a possible unknown pesticide in actual market-place vegetable extracts (tomato skins) using accurate mass and generating empirical formulas. Second is searching either the Merck Index database on CD (10,000 compounds) or the ChemIndex (77,000 compounds) for possible structures. Third is MS/MS of the unknown pesticide in the tomato-skin extract followed by fragment ion identification using chemical drawing software and comparison with accurate-mass ion fragments. Fourth is the verification with authentic standards, if available. Three examples of unknown, non-target pesticides are shown using a tomato-skin extract from an actual market place sample. Limitations of the approach are discussed including the use of A + 2 isotope signatures, extended databases, lack of authentic standards, and natural product unknowns in food extracts.

Synthesis and Antimicrobial Activity of Indole Isoxazolines and Isoxazole Derivatives.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Thiadiazolyl Quinazolones as Potential Antiviral and Antihypertensive Agents.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Alkylindium(I) vs Carbon Monoxide Bridges in Binuclear Iron Carbonyl Complexes: A Theoretical Study

Polynuclear iron carbonyl complexes have been prepared only recently, in which bridging carbonyl ligands were replaced by isolobal monoalkylindium groups. A theoretical analysis of the compounds (CO)3Fe(μ-CO)3-x(μ-InCH3)xFe(CO)3 (x = 0, 1, 2, 3) shows the specific influence of a stepwise substitution of CO by RIn(I) fragments on their electronic, structural, and bonding properties. This influence is determined by the order of the σ donor [RIn(I) ≫ CO(bridge)] and π acceptor [RIn(I) < CO(bridge) ≪ CO(terminal)] capabilities of these ligands.

Membrane Treatment of Secondary Textile Effluents for Direct Reuse

Post-treatment of secondary textile wastewater was tested at pilot scale on membrane modules (microfiltration MF, nanofiltration NF and reverse osmosis RO) for the direct reuse of polished effluent within the dyeing processes. The main polluting parameters monitored in the post-treatment were: organic compounds (COD), colour, surfactants and salinity (as conductivity). The first treatment scheme was made of ceramic MF followed by NF. Aluminium polychloride was added at high concentrations (of the order of 70 mg Al/L) to avoid MF membrane fouling. The quality of the final permeate, produced by NF fed on the MF permeate, was acceptable for water reuse. Clariflocculation (CF) plus multimedia filtration (MMF) followed by low-pressure RO was also tested. This process performed quite well: the RO module (p = 4 bar) ran for relatively long cycles (up to 80 hours) with 5% reduction of the permeate flow rate at a 10 L m−2 h−1 fluxes. A techno-economical analysis on the experimental data indicate that a high quality effluent (COD &amp;lt; 10 mg/l; conductivity &amp;lt; 40 μS/cm; negligible residual colour), to be recycled in the textile dyeing industry, may be produced at affordable costs (less than 0.25 ECU) from secondary textile wastewater.

The 195Pt NMR of L2Pt(1,2-dithiolene) Complexes

The syntheses and characterizations of the novel platinum(II) mono-1,2-dithiolenes (COD)Pt(dddt) (1), (Ph3P)2Pt(dddt) (2), (COD)Pt(edt) (3), (Ph3P)2Pt(edt) (4), (bipy)Pt(edt) (5), and (Ph3P)(CO)Pt(dddt) (6) (COD = 1,5-cyclooctadiene; dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate; edt = ethylene-1,2-dithiolate, bipy = 2,2‘-bipyridyl) are reported. 195Pt NMR spectral analysis was performed on the above-mentioned compounds along with the previously reported compounds (COD)Pt(dmid) (7), (Ph3P)2Pt(dmid) (8), (Ph3P)2Pt(dmit) (9), (COD)Pt(mnt) (10), (Ph3P)2Pt(mnt) (11), (COD)Pt(dt) (12), and (Ph3P)2Pt(dt) (13) (dmid = 1,3-dithiole-2-oxo-4,5-dithiolate; dmit = 1,3-dithiole-2-thione-4,5-dithiolate; mnt = maleonitrile-1,2-dithiolate; dt = ethane-1,2-dithiolate). 195Pt NMR results show that, depending on the nature of L2 in L2Pt(1,2-dithiolene) complexes, the 1,2-dithiolene ligands behave as either π donors or acceptors toward the Pt metal center. 195Pt NMR is also sensitive to the relative electron-withdrawing ability of the substituents on the 1,2-dithiolene backbone which results in an ordering of chemical shifts into a series independent of L2. Support is also provided by electrochemistry, UV−vis spectroscopy, and 13C NMR. X-ray structural analysis results are given for 1, monoclinic, P21/a, a = 10.2420(10) Å, b = 10.7510(10) Å, c = 13.2890(20) Å, β = 102.870(10), Z = 4, and for 5, monoclinic, I2/a, a = 7.2294(2) Å, b = 11.4574(4) Å, c = 14.9103(6) Å, β = 89.380(15), Z = 4.

Membrane treatment of secondary textile effluents for direct reuse

Post-treatment of secondary textile wastewater was tested at pilot scale on membrane modules (microfiltration MF, nanofiltration NF and reverse osmosis RO) for the direct reuse of polished effluent within the dyeing processes. The main polluting parameters monitored in the post-treatment were: organic compounds (COD), colour, surfactants and salinity (as conductivity).The first treatment scheme was made of ceramic MF followed by NF. Aluminium polychloride was added at high concentrations (of the order of 70 mg Al/L) to avoid MF membrane fouling. The quality of the final permeate, produced by NF fed on the MF permeate, was acceptable for water reuse.Clariflocculation (CF) plus multimedia filtration (MMF) followed by low-pressure RO was also tested. This process performed quite well: the RO module (p = 4 bar) ran for relatively long cycles (up to 80 hours) with 5% reduction of the permeate flow rate at a 10 L m−2 h−1 fluxes.A techno-economical analysis on the experimental data indicate that a high quality effluent (COD < 10 mg/l; conductivity < 40 µS/cm; negligible residual colour), to be recycled in the textile dyeing industry, may be produced at affordable costs (less than 0.25 ECU) from secondary textile wastewater.

A Review Paper: Current Knowledge of Ghee and Related Products

Ghee is produced mainly by indigenous methods in Asia, the Middle-East and Africa and the methods of manufacture and characteristics vary. Some ambiguity in the definition of ghee occurs mainly due to regional differences and preferences for the product, commonly used for culinary purposes but also for particular social functions and therapeutic purposes. The characteristic flavour of ghee is its major criterion for acceptance. Flavour is greatly influenced by the fermentation of the cream or butter and the heating processes. Carbonyls, lactones and free fatty acids are reported to be the key ghee flavouring compounds. Ghee is fairly shelf-stable largely because of its low moisture content and possible antioxidative properties. Ghee may contain high amounts of conjugated linoleic acid, a newly reported anticarcinogen. However, it is also reported that, under certain circumstances, it may contain certain amounts of cholesterol oxidation compounds (COPS) which may cause adverse health effects.

Kooperative Wirkung in π-Ligand-verbrückten Zweikernkomplexen XX Eine neue Strategie zur Synthese von heterodinuklearen Komplexen mit einem verbrückenden Bis(cyclopentadienyl)-Liganden

Abstract The reaction of {M}[ η 5 -C 5 H 4 C(O)OMe]({M} = W(CO) 3 Me: 1a ; {M} = Mn(CO) 3 : 1b ) with tetramethylcyclopentadienyllithium and Me 3 SiCl, subsequently, reveals {M}[ η 5 -C 5 H 4 C(OTMS)(C 5 Me 4 )](OTMS = OSiMe 3 ; {M} = W(CO) 3 Me: 2a ; {M} = Mn(CO) 3 : 2b ) in high yields. Hydrolysis of 2a and 2b results quantitatively in the formation of {M}[ η 5 -C 5 H 4 C(O)(C 5 Me 4 H)] ({M} = W(CO) 3 Me: 3a ; {M} = Mn(CO) 3 : 3b ). 2a,b and 3a,b are versatile precursors for the synthesis of homo- and heterodinuclear complexes containing a bis(cyclopentadienyl) ketone ligand. Deprotonation of 3a and further reaction with [Rh(CO) 2 Cl] 2 yields (Me)(CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(CO) 2 ( 4a ). 4a is also obtained by using 2a instead of 3a . Taking 2a and 2b in corresponding reactions, (CO) 3 Mn[ η 5 ( Mn )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(CO) 2 ( 4b ), (Me)(CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( Rh )-(C 5 Me 4 )]Rh(C 7 H 8 ) ( 5 ) (C 7 H 8 = norborna-2,5-diene) and (CO) 3 Mn[ η 5 ( Mn )-(C 5 H 4 )C(O)- η 5 ( Ir )-(C 5 Me 4 )]Ir(C 8 H 12 ) ( 6 ) (C 8 H 12 = cycloocta-1,5-diene) can be synthesized as well. Heating of 3a,b with Co 2 (CO) 8 and 3,3-dimethylbut-l-ene in refluxing THF affords {M}[ η 5 ( M )-(C 5 H 4 )C(O)- η 5 ( Co )-(C 5 Me 4 )]Co(CO) 2 ({M} = W(CO) 3 Me: 7a ; {M} = Mn(CO) 3 : 7b ). The metal-metal bound compounds (CO) 3 W[ η 5 ( W )-(C 5 H 4 )C(O)- η 5 ( M )-(C 5 Me 4 )]M(CO) 2 ( W—M ) (M = Ru: 8 ; M = Fe: 9 ) are formed during the reaction of 3a with the corresponding carbonyl metal complexes in refluxing diglyme. Heating of 3a with a 4.5-fold excess of Fe(CO) 5 yields the homodinuclear complex (CO) 2 Fe[ η 5 -(C 5 H 4 )C(O)- η 5 -(C 5 Me 4 )]Fe(CO) 2 ( Fe-Fe ) ( 10 ) and (CO) 3 W[ η 5 ( W )-(C 5 H 4 )CH 2 - η 5 ( Fe )-(C 5 Me 4 )]Fe(CO) 2 ( W-Fe ) ( 11 ) as unexpected products. 11 contains a completely hydrogenated sp 3 carbon atom as a linker between the two cyclopentadienyl moieties. X-ray diffraction studies of 2b, 5, 7a, 8 and 10 are reported.

Synthesis and Spectroscopic Characterization of (CO)6Fe2{μ-EC(H)C(H)E‘} (E ≠ E‘; E, E‘ = S, Se, Te) and (CO)6Fe2{μ-TeC(H)C(H)Te}. Structural Characterization of (CO)6Fe2{μ-SC(Ph)C(H)Se} and (CO)6Fe2{μ-SC(H)C(Ph)Te}

When acetylene gas was bubbled through methanol solutions containing the mixed-chalcogenide compounds (CO)6Fe2(μ-EE‘) (E ≠ E‘; E, E‘ = S, Se, Te), the acetylene adducts (CO)6Fe2{μ-EC(H)C(H)E‘} (1, 52%, E, E‘ = S, Se; 2, 46%, E, E‘ = S, Te; 3, 38%, E, E‘ = Se, Te) were obtained. In addition, trace amounts of the homochalcogenide derivatives (CO)6Fe2{μ-EC(H)C(H)E} (E = S, Se, Te) were also obtained. The Te2 compound (CO)6Fe2{μ-TeC(H)C(H)Te} (4) was obtained in 32% yield from the reaction of (CO)6Fe2(μ-Te2) with acetylene. Compounds 1−4 were characterized by IR and 1H, 13C, 77Se, and 125Te NMR spectroscopy. Crystallographic analysis of the phenylacetylene adducts (CO)6Fe2{μ-SC(Ph)C(H)Se} (5) and (CO)6Fe2{μ-SC(H)C(Ph)Te} (6) were carried out. The structures of both 5 and 6 can be described as Fe2SE (E = Se, Te) tetrahedral butterfly cores containing the phenylacetylene as a bridge between the two wingtip chalcogen atoms, with three terminally bonded carbonyl groups on each Fe atom.

Diacetylene-bridged clusters: Synthesis and characterization of (CO) 6Fe 2Se 2{ μ-HCC(CCR)}, {(CO) 6Fe 2Se 2} 2{ μ-HCC(CCR)} (RMe on n-Bu) and (CO) 6Fe 2Se 2( μ-HCCCCCH 3 OS 3(CO) 10

The compounds (CO) 6Fe 2Se 2{ μ- HC C( C CR)} (R=Me ( 1) or n-Bu ( 2) and {(CO) 6Fe 2Se 2} 2{ μ-HCC(CCR)} (RMe ( 3) or n-Bu ( 4)) have been obtained by room-temperature reactions of Fe 2(CO) 6(μ-Se 2) with HCCCCR. Compound 1 Os 3(CO) 10(NCMe) 2 to give (CO) 6Fe 2Se 2( μ-HCCCCCH 3OS 3(CO) 10 ( 5). The structure of compounds 1, 3 and 5 have been established by single-crystal X-ray diffraction studies.

Synthese und struktur zweikerniger cyclopentadienyltricarbonylmangan-komplexe vom Typ (CO)3Mn[(η5-C5H4)-X-(η 5-C5H4)]Mn(CO)3

The synthesis of various members of the family of title compounds (CO)3Mn[(η5-C5H4)-X-(η5-C5H4)] MnCO)3 has been achieved by a variety of methods: the mononuclear bridging groups X  S (1a) and X  Si(C6 H5)2 (1b) have been introduced by standard methods via (η5-C5H4Li)Mn(CO)3. The dicarbon bridging entities MeCCMe and MeC(OH)(OH)CMe have been formed by reductive coupling of the corresponding ring acetylated complexes. Reductive coupling of [η5-α-C5H3CH3(COCH3)]Mn(CO)3 (2a) under mild conditions with TiCl3/LiAlH4 leads to the corresponding vicinal diol (CO)3Mn[η5-C5H3(α-CH3)] C(OH)(CH3)C(OH)(CH3)[η5-C5H3(α-CH3)]Mn(CO)3 (3). Under less mild conditions the McMurry type reduction leads to the corresponding olefin (CO)3Mn[η5-C5H3(α-CH3)]C(CH3)C(CH3)[η5 -C5 H3(α-CH3)]Mn(CO)3 (4a). The olefin is obtained as a mixture of Z/E- and R/S-isomers; the corresponding four diastereomeric forms of 4a are separable by capillar gas chromatography. Using the same approach the β-isomer [η5-β-C5H3CH3(COCH3)]Mn(CO)3 (2b) yields a mixture of the four isomers of (CO)3Mn[η 5-C5H3(β-CH3)]C(CH3)C(CH3)[ η5-C5H3(β-CH3)]Mn(CO)3 (4b). In an analogous way (η5-C5H4-COCH3)Mn(CO)3 (5) is coupled to give the Z-(6a) and E-isomers (6b) of (CO)3 Mn[η5-C5H4]C(CH3)C(CH3)[η5-C5H4]Mn(CO)3. The isomers are easily separated by column chromatography. As a binuclear species closely related to the title compounds, {η5-C5H3CH3 [β-COCH2(η6-C6H5)Cr(CO)3]}Mn(CO)3 (8) is obtained by Cr(CO)3-complexation of {η5-C 5H3CH3[β-COCH2(C6H5)]}Mn(CO)3 (7). All the compounds have been characterised by the usual spectroscopic and analytical techniques. In addition the compounds 1a, 1b, 2a, the meso-form of 3, 3a, 6a, 6b and 8 have been characterised by X-ray analyses.

Additionsreaktionen von (CO) 5CrEPhH 2(E  P As) an di(ethinyl)-phosphane und stannane; stufenweise darstellung von komplex-gebundenen 1,4-dihetero-cyclohexa-2,5-dienen

The compounds (CO) 5CrEPhH 2 (E  P, II; E  As, VIII) react with RP(CCH) 2 (R  tBu, Ia; R  CH 2Ph, Ib) and Me 2Sn(CCPh)2 ( V) via insertion into the EH bonds to give 1,4-dihetero-cyclohexa-2,5-diene complexes of the type [(CO) 5Cr](Ph) PCHCHXCHC H (X  RP, III; X  PhAs, IX) and [(CO) 5Cr](Ph)PC(Ph)CHSnMe 2CHC (Ph) ( VII) in high yields. The insertion of the dialkynes is stereospecific: trans addition of II to V yields first [(CO) 5Cr](Ph)(H)PC(Ph)CHSnMe 2C CPh ( VI) a compound in which the phosphorus group and the Me 2Sn(CCPh) unit are in cis position to each other. Ring closure by insertion of the second phenylethynyl group in VI into the PH bond affords the six membered cycle of [(CO) 5Cr](Ph) P  C(Ph)CHSnMe 2CHC (Ph) ( VII). Another way to synthesize complexes of the type VII is given in the reaction of I with H 2Sn nBu 2 ( XIII). In the presence of KOH/18-Crown-6, the cycles of R PCHCHSn nBu 2CHC H (R  tBu, XIVa; R  CH 2Ph, XIVb) are formed, which then yields by treatment with (CO) 5Cr(Thf) ( XV), [(CO) 5Cr](R) PCHCHSn nBu 2CHC H (R  tBu, XVIa; R  CH 2Ph, XVIb). A compound, in which both hetero-atoms of the 1-phospha-4-arsacyclohexa-2,5-diene ( IXa) are bonded to a 16-electron complex fragment can be synthesized by the reaction of IXa with (CO) 5Mo(Thf) ( X). [(CO) 5Cr]( tBu) P CHCHAs(Ph)[Mo(CO) 5]CHC H ( XII) can be isolated in high yields. The identity of all new synthesized compounds III, VI, VII, IX, XII, XIV and XVI is confirmed by analytical and spectroscopic (IR, MS, 1H, 13C and 31P NMR) data as well as by an X-ray diffraction study of IXa.

Stereoselektive additionsreaktionen von komplexgebundenen phosphanen und arsanen an alkine

The compounds (CO) 5CrEPh m H 3- m (E=P, As; m = 1,2) react with alkynes with insertion into the PH or AsH bonds to yield L n M derivatives of vinyl-substituted phosphines (III, VI, VIII) or arsines (X, XI). The insertion of the acetylenes is stercospecific: trans-addition of the acetylenes HCCR (R = Ph, PPh 2, Me 2Si(CCH), (Me)(Ph)Si(CCH)) used yields the compounds (CO) 5CrPPh 2(CHCHR) (III, R = Ph; VI, R = PPh 2) or (CO) 5CrP(Ph)(H)(CHCHR) (VIIIa, R = Ph; VIIIb, R = PPh 2; VIIIc, R = (Me)(Ph)Si(CCH); VIIId, R = Me 2Si(CCH)), in which the R group and the phosphorus group are in the cis position to each other. Depending on the steric demand of the alkynes used, either one or both of the AsH functional groups in (CO) 5CrAsPhH 2 (IX) will react: PhCCPh inserts into only one AsH bond (formation of (CO) 5CrAs(Ph)(H)(PhCCHPh (X)), whereas the sterically less demanding acetylenes HCCPH and (Me)(Ph)Si(CCH) 2 insert into both AsH groups (formation of (CO) 5CrAs(Ph)(CHCHR) 2 (XIa, R = Ph; XIb, R = (Me)(Ph)Si(CCH))). In general, by reaction of (CO) 5CrPPhH 2 (VII) with (R)(R′)Si(CCH) 2 (IIc, R = Me, R′= Ph; IId, R = R′ = Me), only one alkynyl unit of IIc,d inserts into the PH bond to yield (CO) 5CrP(Ph)(H)[CHCHSi(R)(R′)(CCH)] (VIIIc, R = Me, R′= Ph; VIIId, R = R′= Me), respectively. Ring closure by insertion of the second alkynyl group is not observed under the conditions used. However, the second alkynyl unit in VIIId reacts with Co 2(CO) 8 to form (CO) 5CrP(Ph)(H)(CHCHSi(Me)(Ph)[(η 2-CCH)Co 2(CO) 6]) (XIII) in high yields.

(Tetracyannaphthalocyaninato)eisen(II) mit Isocyaniden als axialen Liganden

(Tetracyanonaphthalocyaninato)iron(II) with Isocyanides as Axial Ligands(Tetracyanonaphthalocyaninato)iron(II) [(CN)4‐2,3‐NcFe; 6] is obtained by treating 2,3,6‐tricyanonaphthalene (5) with iron(II) acetate. Compound 5 is synthesized according to the route given in Scheme 1. The mononuclear bisaxial isocyanide complexes (CN)4‐2,3‐NcFeL2 7–9 with L = tBuNC, cHxNC and AdNC as well as the bridged complex [(CN)4‐2,3‐NcFe(dib)]n (10) are formed as stable compounds by treating 6 with the neat ligands L. The spectroscopic properties of the complexes are described and compared with the analogous compounds (CN)4PcFeL2, 2,3‐NcFeL2, 1,2‐NcFeL2, and with PcFeL2. The bridged complex [(CN)4‐2,3‐NcFe(dib)]n (10) exhibits only poor semiconducting properties as compared to [2,3‐NcFe(dib)]n. The oligomer 10 can be doped with iodine, and the resulting product [(CN)4‐2,3‐NcFe(dib)I1.4]n shows a powder conductivity s̀RT = 2 × 10‐5 S/cm at room temperature.

Übergangsmetallstabilisierte As I- und Sb I-Chelate

The dimetallaarsacumuleniumion [Cp′(CO) 2MnAsMn(CO) 2Cp′] +, 2, (Cp′ = η 5-C 5H 4CH 3) obtained from the arsinidene compound ▪, 1a, reacts with dipy to give the cationic arsenic(I) chelate compound [Cp′(CO) 2Mn] 2 As[dipy] +, which has been isolated and structurally characterized as its CF 3SO 3 − salt, 3a. ortho-Phenanthroline as the chelate ligand gives the corresponding o-phen chelate, isolated as its triflate 3b. In contrast to the arsinidene compound ▪, 1a, which has first to be transformed into the cumulenic system [Cp′(CO) 2MnAsMn(CO) 2Cp′] +, 2, in order to synthesize 3a, 3b, the “inidene” compounds (CO) 5 ▪, 1b, and ▪ Cp′, 1c, undergo a spontaneous reaction with dipy to form the salts [L n M] 2Xdipy +[L n M] 2XCl 2 (L n M = (CO) 5Cr, X = As: 3c; L n M = Cp′(CO) 2Mn, X = Sb: 3d). X-ray analyses of 3c, 3d reveal the tetrahedral coordination around the main group centers X(I) in the cationic as well as in the anionic constituents of 3a (X = As) and 3d (X = Sb). Comparison of the structures known for chelate compounds of the type [L n M] 2dipy + (X = As, Sb, Bi) shows a systematic trend in the relative importance of XN- vs. XM-bonding for these species.

Reaktionen koordinierter liganden VI. Stabilisierung von RP(OH) 2, RPHNEt 2 und RPHCl als liganden in (CO) 5ML

Starting from compounds (CO) 5MPRClNEt 2 (M = Cr, Mo, W) several new complexes have been obtained in which phosphines—non-existent or having a different tautomeric structure in the free state—are stabilized by coordination to a metal(0) centre. Thus, hydrolysis yields (CO) 5CrPR(OH) 2, methanolysis (CO) 5CrPR(OMe)NEt 2 and reduction with LiAlH 4 (CO) 5MPRHNEt 2. The latter were converted into (CO) 5MPRHCl with gaseous HCl.

Reduction of (μ 2-Te 2)Fe 2(CO) 6 and reaction of the dianion formed with metal dihalides, L 2MCl 2, (L = PPh 3, M = Pt, Pd, Ni; L = C 5H 5, M = Ti; L = Me, n-Bu, M = Sn)

Treatment of a THF solution of (μ 2-Te 2)Fe 2(CO) 6 with LiEt 3BH at −78°C gives the dianion [(μ-Te) 2Fe 2(CO) 6] 2−. The dianion reacts with the metal dihalides (PPh 3) 2MCl 2, M = Pt, Pd, Ni, to give the neutral compounds (CO) 6Fe 2(μ 3-Te) 2M(PPh 3) 2, with Cp 2TiCl 2 to give (CO) 6Fe 2(μ 3-Te) 2TiCp 2, or with R 2SnCl 2, R = Me, n-Bu to give (CO) 6Fe 2(μ 3-Te) 2SnR 2.