Mixed isocyanide-1,4-diaza-1,3-butadiene complexes of molybdenum and tungsten-II. Species of the type [M(CO)3(CNR)(R′-DAB)]1+,0,1−

The complexes M(CO)₄(R′-DAB) (M = Mo or W; R′-DAB = R′NCHCHNR′; R′ = i-Pr, t-Bu, Cy or p-tol) undergo substitution of a single CO ligand by isocyanide ligands RNC (R = Me, CHMe₂, CMe₃, C₆H₁₁ or xylyl), in refluxing toluene to give fac-M(CO)₃(CNR)(R′-DAB). Synthesis of the latter complexes can also be achieved, at ambient temperature, through the use of the nitrile complexes, Mo(CO)₃(NCMe)₃ and W(CO)₃(NCEt)₃: the method involves substitution of the nitrile ligands first by R′-DAB, then by RNC. The intermediate compounds Mo(CO)₃(NCMe)(R′-DAB) and W(CO)₃(NCEt)(R′-DAB) have also been isolated and characterized. Oxidation of dark blue-purple Mo(CO)₃(NCMe)(t-Bu-DAB) and Mo(CO)₃(CNR)(t-Bu-DAB)(R = Me or CMe₃) with [Cp₂Fe]PF₆ in dichloromethane solution produces the paramagnetic (17-electron), orange complexes [Mo(CO)₃(NCMe)(t-Bu-DAB)PF₆ and [Mo(CO)₃(CNR)(t-Bu-DAB)]PF₆, respectively. The molybdenum cations, [Mo(CO)₃(NCMe)(t-Bu-DAB)]PF₆ and [Mo(CO)₃(CNCMe₃)(t-Bu-DAB)]PF₆, react with two and one equivalent of tert-butyl isocyanide, respectively, to yield dark red cis, trans-[Mo(CO)₂(CNCMe₃)₂)t-Bu-DAB)]PF₆. Reduction of cis, trans-[Mo(CO)₂(CNCMe₃)₂)(t-Bu-DAB)]PF₆ with cobaltocene in acetone yields the analogous dark blue zerovalent species cis, trans-Mo(CO)₂(CNCMe₃)₂(t-Bu-DAB). The compounds [Mo(CO)(CNR)₄(t-Bu-DAB)](PF₆)₂ and Mo(CO)₃(CNR)(t-Bu-DAB) are produced, via a disproportionation reaction, when solutions of the cations [Mo(CO)₃(CNR)(t-Bu-DAB)]⁺ (R = Me or CMe₃) are reacted with ∼three equivalents of RNC. On the other hand, the reaction between tert-butyl isocyanide and [Mo(CO)₃(CNCMe₃)(i-Pr-DAB)]⁺ gives seven-coordinate [Mo(CNCMe₃)₅(i-Pr-DAB)](PF₆)₂ and Mo(CO)₃(CNCMe₃)(i-Pr-DAB). The ligand-based reduction of the complexes M(CO)₃(CNR)(R′-DAB) (M = Mo or W) is readily accessible in THF upon addition of one molar equivalent of THF-soluble LiEt₃BH to yield solutions that contain the radical anions [M(CO)₃(CNR)(R′-DAB)]^−.. The complexes synthesized in this work have been characterized on the basis of their spectroscopic and electrochemical properties, including ESR spectral studies on the paramagnetic 17- and 19-electron complexes.     

Organosilyl and organogermyl isocyanide complexes of group vib metal carbonyls

Syntheses of twelve M(CO)₅L complexes (M  Cr, Mo, W; L  CNSiR₂R′, CNGeR₂R′ for R,R′  Me,Ph) were accomplished by carbonyl displacement from M(CO)₆ by L. Several cis-Mo(CO)₄L₂ complexes and one fac complex, Mo(CO)₃(CNGeMe₃)₃, are also reported, prepared by displacement of bicycloheptadiene or cycloheptatriene from Mo(CO)₄(bicycloheptadiene) and Mo(CO)₃(cycloheptatriene). Infrared and ¹³C NMR spectra confirm that the ligands are isocyanides rather than cyanides although the latter is the stable and predominate form of the pure ligands. The mono-substituted compounds are only moderately stable when sealed in vacuo; otherwise stored they decompose rapidly probably by virtue of reaction with oxygen. The phenylsilyl and phenylgermyl isocyanide complexes are harder to store than the methyl analogues. The bis and tris complexes were very difficult to study, being thermally very unstable as well as reactive toward oxygen so that characterization of these species was only marginally successful.     

Nitrogen donor ligands bearing N–H groups: Effect on catalytic and cytotoxic activity of molybdenum η3-allyldicarbonyl complexes

Reactions of [Mo(η³-C₃H₅)Br(CO)₂(NCMe)₂] with the bidentate nitrogen ligands 2-(2′-pyridyl)imidazole (L1), 2-(2′-pyridyl)benzimidazole (L2), N,N′-bis(2′-pyridinecarboxamido)-1,2-ethane (L3), and 2,2′-bisimidazole (L4) led to the new complexes [Mo(η³-C₃H₅)Br(CO)₂(L)] (L = L1, 1; L2, 2; L4, 4) and [{Mo(η³-C₃H₅)Br(CO)₂}₂(μ-L3)] (3).The reaction of complexes 2 and 3 with Tl[CF₃SO₃] afforded [Mo(η³-C₃H₅)(CF₃SO₃)(CO)₂(L2)] (2T) and [{Mo(η³-C₃H₅)(CF₃SO₃)(CO)₂}₂(μ-L3)] (3T).Complexes 3 and 2T were structurally characterized by single crystal X-ray diffraction, showing the facial allyl/carbonyls arrangement and the formation of the axial isomer. In 2T, two molecules are assembled in a hydrogen bond dimer.The four complexes 1–4 were tested as precursors in the catalytic epoxidation of cyclooctene and styrene, in the presence of t-butylhydroperoxide (TBHP), with moderate conversions and turnover frequencies for complexes 1–3 and very low ones for 4. The increasing number of N–H groups in the complexes seems to be responsible for the loss of catalytic activity, compared with other related systems. The cytotoxic activities of all the complexes were evaluated against HeLa cells. The results showed that compounds 1, 2, 4, and 2T exhibited significant activity, complexes 2 and 2T being particularly promising.     

The influence of the nature of the ligand,L, on the electrochemical behaviour of dinitrosyl molybdenum complexes,Mo(NO)2L2Cl2, in aprotic media

Electrochemical investigations of the reduction of dicationic, monocationic and neutral dinitrosyl molybdenum complexes in nitromethane and acetonitrile are reported. All the compounds with the general formulae: [Mo(NO)₂L₂L′₂]²⁺, [Mo(NO)₂L₂L′Cl]⁺ and Mo(NO)₂L₂Cl₂ (L = CH₃CN, CH₂CHCN, C₆H₅CN, C₅H₅N, P(C₆H₅)₃, L₂ = 2,2′-bipyridine, L′ = CH₃CN and L′₂ = 2,2′-bipyridine) are reducible by one electron to yield 19-electron complexes. The dicationic complexes undergo a reversible one-electron transfer. For the mono- and dichlorocomplexes, the one-electron transfer induces the facile exchange of the chloroligand in the 19-electron complexes except for L₂ = 2,2′-bipyridine. However, the exchange of the chloroligand is followed by the fast anation by Cl^? of the remaining 18-electron chlorocomplexes to afford [Mo(NO)₂Cl₃L]^? and [Mo(NO)₂Cl₄]^2? which are reducible at higher negative potentials than dichloro- and monochlorocomplexes. The multiple electrochemical step system is not catalytic, but of the electroactivation type.     

Molybdenum carbonyl complexes of binucleating pyridine-based ligands

Reaction of [Mo(CO)₄(diene)] with 4,4′-bipyridine (44′B), trans-1,2-bis(2-pyridyl)ethene (2-bpe) and trans-1,2-bis(4-pyridyl)-ethene (4-bpe) gives polymeric [Mo(CO)₄(44′B)]_n, mononuclear cis-[Mo(CO)₄(2-bpe)₂] and binuclear [Mo(CO)₄(4-bpe)]₂ respectively. Reaction of the same ligands with [Mo(CO)₄(bpy)] (bpy is 2,2′-bipyridine) produces the bridged binuclear complexes [{Mo(CO)₃(bpy)}₂(44′B)] and [{Mo(CO)₃(bpy)}₂(4-bpe)]. Products are characterised by microanalysis and spectroscopy (IR, ¹H NMR, UV/vis). Reduction of [{Mo(CO)₃(bpy)}₂(44′B)] produces an anion in which the unpaired electron is localised on the chelating bpy ligand.     

Reactivity of [M(CO)3(NN)(thioureas)] (M = Mo,W; NN = 2,2′bipyridine, 1,10-phenanthroline) complexes towards systems with mercury-halides bonds. Trimetallic compounds with XMHgM′X (M′ = Mo,W; X = Cl,Br, I) bondings

New heterotrimetallic complexes were isolated by reaction of M(CO)₃(NN)L (M = Mo, W; NN = bipy, phen; L = thioureas) either with HgX₂ (X = Cl, Br, I) giving complexes of the formula [M(CO)₃(NN)(X)]₂Hg or with M′(CO)₃(NN′)(Cl)(HgCl) (M′ = Mo, W; NN′ = bipy, phen) producing compounds of the type (Cl)(NN)(CO)₃MHgM′(CO)₃(NN′)(Cl). These new photosensitive substances were characterized through IR spectroscopy and conductivity measurements. Structures involving XMHgM′X bonding are proposed and the reactions are discussed in terms of an insertion of the fragment M(CO)₃(NN) into the HgX bonds.     

The preparation and characterisation of a series of cationic bimetallic linear triphos-bridged complexes of the type [Mo (CO) (L,L′ or L″–P) (η2-RC2R′)Cp] [BF4] {L,L′ or L″= [WI2 (CO){PhP(CH2CH2PPh2)2–P,P′} (η2-RC2R′)] (L,R=R′=Me; L′,R=R′=Ph; L″,R=Me,R′=Ph}

Equimolar quantities of [Mo (CO) (η²-RC₂R′)₂Cp] [BF₄] (R=R′=Me Ph R=Me R′=Ph) and L L′ or L″ {L L′ or L″= [WI₂ (CO){PhP(CH₂CH₂PPh₂)₂-PP′} (η²-RC₂R′)]} (L R=R′=Me L′ R=R′=Ph L″ R=Me R′=Ph) react in CH₂Cl₂ at room temperature to give the new bimetallic complexes[Mo (CO) (L L′ or L″–P) (η²-RC₂R′)Cp] [BF₄] (1–9) via displacement of the alkyne ligand on the molybdenum centre The complexes have been characterised by elemental analysis IR and ¹ H NMR spectroscopy and in selected cases by ³¹ P NMR spectroscopy.     

Übergangsmetallphosphidokomplexe. XIII. P-funktionelle phosphidoverbrückte Heterozweikernkomplexe mit und ohne Metall-Metall-Bindung; P(SiMe3)2-verbrückte cp(CO)xFe-Derivate

Transition Metal Phosphido Complexes. XIII. P-functional Phosphido-Bridged Heterobimetallic Complexes with and without a Metal-Metal Bond; P(SiMe₃)₂-Bridged cp(CO)_xFe Derivatives cp(CO)₂FeP(SiMe₃)₂ 1 reacts with the carbonyl nitrosyl complexes Co(CO)₃(NO), Fe(CO)₂(NO)₂,Mn(CO)(NO)₃ substituting a CO ligand and with the THF complexes M′(CO)₅THF(M′ = Cr, Mo, W), Mncp(CO)₂THF MnMecp(CO)₂ which can be obtained in solution substituting the THF ligand to give the phosphido-bridged bimetallic complexes cp(CO)₂Fe[μ-P(SiMe₃)₂]M′L_m 2 (M′L_m = Co(CO)₂(NO) b , Fe(CO)(NO)₂ c , Mn(NO)₃ d , Cr(CO)₅ f , Mo(CO)₅ g , W(CO)₅ h , Mncp(CO)₂ i , MnMecp(CO)₂ j ). Solutions of Li(Me₃Si)₂PM′L_m 4e–l (M′L_m = Fe(CO)₄ e , Crcp(CO)(NO) k , Vcp(CO)₃ l ) are available by a selective cleavage reaction of a Si? P bond in the complexes (Me₃Si)₃PM′L_m 3e–l using n-BuLi. Reactions of cp(CO)₂FeBr with 4e–l give the bimetallic complexes 2e–l . The open-chain complexes 2c, 2f, 2h–k undergo a photochemical decarbonylation reaction to form the phosphido-bridged bimetallic complexes cp(CO)Fe[μ-CO, μ-P(SiMe₃)₂]M′L_m?1(Fe-M′) 5 (M′L_m?1 = Fe(NO)₂ c , Cr(CO)₄ f , W(CO)₄ h , Mncp(CO) i , MnMecp(CO) j , Crcp(NO) k ) containing a metal-metal bond. Equilibria between various isomers can partially be observed in solutions of the complexes 5. I.R., N.M.R., and mass spectral data are reported.     

Metallkomplexe mit 1,2-Dithion-Liganden. III. Dithiooxamide als starke Donatoren oder Akzeptoren in Molybdäncarbonylkomplexen

Metal Complexes with 1,2-Dithione Ligands. III. Dithiooxamides as Strong Donors or Acceptors in Molybdenum Carbonyl Complexes. Starting from substitution labile molybdenum carbonyl complexes L₂Mo(CO)₄, L₃Mo(CO)₃ and L₂L₂′Mo(CO)₂ several new complex types with the C? C-twisted tetraalkyldithiooxamides (R₄dto) and the planar N,N′-dialkyldithiooxamides (R₂H₂dto) such as (R₄dto)Mo(CO)₄ ( 8 – 11 ), (R₂H₂dto)Mo(CO)₄ ( 12 – 18 ), (R₂R₂′dto)Mo(CO)₃(P(C₆H₅)₃) ( 27 – 31 ), (R₂R₂′dto)Mo(CO)₂(PR₃)₂ ( 36 – 51 ) are described and compared with complexes of a cyclic dithiooxamide ( 62 – 64 ) and analogous complexes with thioamides R₂NC(S)R′ ( 19 – 25 , 52 – 55 , 57 – 60 ). In Mo(CO)₄ complexes, dithiooxamides display a rather strong donor character and are thus similar to simple thioamides, but the blue colour of the R₂H₂dto complexes indicates already low-lying acceptor levels. When passing from the Mo(CO)₄ complexes via Mo(CO)₃(PR₃) complexes to the very electron rich Mo(CO)₂(PR₃)₂ complexes, the i.r. and eletronic spectra indicate an unexpected and drastic change in ligand character. Dto ligands in the latter complex type turn out to be very strong acceptors, independent of the degree of N-alkylation. A conformational change, with twisted R₂N? C bonds and a planar S? C? C? S skeleton (as in the dithiolene complexes), can account for all the peculiarities of the (dto)-dicarbonylbis(phosphine) complexes as compared to the “normal” thioamide complexes. Dithiooxamides can thus control the oxidation state of metals by a remote conformational change and possibly act as an electron reservoir in chemical reactions at the metal center.     

Synthesis,Structure and Reactivity of [1, 2‐Bis(diphenylphosphinite)ethane]bromotricarbonylmanganese(I) with Reactions of Phosphites,Phosphonites. and Phosphinites

The manganese carbonyl complex [MnBr(CO)₃ L ] ( 1 ), where L = Ph₂POCH₂CH₂OPPh₂, was prepared by reacting [MnBr(CO)₅] with the bidentate ligand 1, 2‐Bis(diphenylphosphinite)ethane. From this compound and the appropriate phosphite, phosphinite or phosphonite ligands were synthesized the complexes [MnBr(CO)₂ LL ′], where L ′ = P(OMe)₃ ( 2 ) or P(OEt)₃ ( 3 ) and [MnBr(CO)₃ L ′₂], where L ′ =PPh(OEt)₂ ( 4 ) or PPh₂(OEt) ( 5 ). The obtained compounds have been characterized by elemental analysis, mass spectrometry, IR and NMR (¹H, ¹³C and ³¹P) spectroscopies and X‐ray diffractometry for the complexes 1 , 4 and 5 .     

Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Darstellung,Eigenschaften und Molekülstrukturen von Komplexen des versteiften dreizähnigen Chelatliganden N,N′-Bis(diphenylphosphino)-2, 6-diaminopyridin mit MII - und M0-Übergangsmetallen [MII = Ni,Pd, Pt; M0 = Cr,Mo, W]

Preparation, Properties, and Molecular Structures of a Rigid Tridentate Chelate Ligand N, N′-Bis(diphenylphosphino)-2, 6-diaminopyridine with M^II and M⁰ Transition Metals [M^II = Ni, Pd, Pt; M⁰ = Cr, Mo, W] The reaction of chlorophenylphosphane and 2, 6-Diaminopyridine give N, N′-Bis-(diphenylphosphino)-2, 6-diaminopyridine (PNP). Two types of complexes [M(PNP)Cl]Cl · L (M = Ni, L = H₂O; M = Pd, L = C₂H₅OH; M = Pt) and mer-[M(PNP)(CO)₃] · 2 THF (M = Cr, Mo, W) have been prepared using PNP. These coordination compounds have been characterized by means of i.r., u.v., ³¹P and ¹H n.m.r. measurements. The determination of the molecular structure of the two triclinic substances mer-[Mo(PNP)(CO)₃] · 2 THF and [Ni(PNP)Cl]Cl · H₂O show that the octahedral Mo(d⁶) and the square planar nickel (d⁸) compounds contain a nearly planar tridentate chelate ring system (two fused five-membered rings of the type ) in which the observed bond distances are in accordance with a π electron delocalization effect. The observed gram susceptibility of the diamagnetic Ni(d⁸) compound remains unchanged between 293 and 410 K. The relative activation property for a homogenous catalytic standard hydrogenation reaction of styrene to ethylbenzene decreases in series of catalysts of type [M(PNP)Cl]Cl · L with M^II = Ni > Pd > Pt.     

Substitution reactions of [MBr(π allyl)(CO)2(LL)] complexes (M = Mo,W; L-L = 2,2 -bipyridine 1,2-bis(diphenylphosphine)ethane) with xanthates and dithiocarbamates

The complexes [MBr(π-allyl)(CO)₂(bipy)] (M = Mo, W, bipy = 2,2′-bipyridine) react with alkylxanthates (M^IRxant), and N-alkyldithiocarbamates (M^IRHdtc) (M^I = Na or K), yielding complexes of general formula [M(S,S)- (π-allyl)(CO)₂(bipy)] (M = Mo, (S,S) = Rxant (R = Me, Et, t-Bu, Bz), RHdtc (R = Me, Et); M = W, (S,S) = Extant). A monodentate coordentate coordination of the (S,S) ligand was deduced from spectral data. The reaction of [MoBr(π-allyl)(CO)₂(bipy)] with MeHdtc and Mexant gives the same complexes whether pyridine is present or not. The complexes [Mo(S,S)(π-allyl)(CO)₂(bipy)] ((S,S) = MeHdtc, Mexant) do not react with an excess of (S,S) ligand and pyridine.No reaction products were isolated from reaction of [MoBr(π-allyl)(CO)₂(dppe)] with xanthates or N-alkyldithiocarbamates.     

Photochemical reactions of metal carbonyls [M(CO)6 (M = Cr,Mo and W), Re(CO)5Br,Mn(CO)3Cp] with 2-hydroxyacetophenone methanesulfonylhydrazone (apmsh)

Five new complexes, [M(CO)₅(apmsh)] [M = Cr; (1), Mo; (2), W; (3)], [Re(CO)₄Br(apmsh)] (4) and [Mn(CO)₃(apmsh)] (5) have been synthesized by the photochemical reaction of metal carbonyls [M(CO)₆] (M = Cr, Mo and W), [Re(CO)₅Br], and [Mn(CO)₃Cp] with 2-hydroxyacetophenone methanesulfonylhydrazone (apmsh). The complexes have been characterized by elemental analysis, mass spectrometry, f.t.-i.r. and ¹H spectroscopy. Spectroscopic studies show that apmsh behaves as a monodentate ligand coordinating via the imine N donor atom in [M(CO)₅(apmsh)] (1–4) and as a tridentate ligand in (5).     

Reaction of metal carbonyls with 2-hydroxy-1-naphthaldeyde methanesulfonylhydrazone and characterization of the substitution products

Five new complexes, [M(CO)₅(nafmsh)] [M?=?Cr, 1; Mo, 2; W, 3], [Re(CO)₄Br(nafmsh)], 4 and [Mn(CO)₃(nafmsh)], 5 have been synthesized by the photochemical reaction of metal carbonyls [M(CO)₆] (M?=?Cr, Mo, W), [Re(CO)₅Br], and [Mn(CO)₃Cp] with 2-hydroxy-1-naphthaldehyde methanesulfonylhydrazone (nafmsh). The complexes have been characterized by elemental analysis, EI mass spectrometry, FT-IR, and ¹H NMR spectroscopy. The spectroscopic studies show nafmsh is a monodentate ligand coordinating via the imine N donor atom in 1–4 and as a tridentate ligand in 5.     

Two molybdenum pentacarbonyl complexes with electroneutral phosphane ligands: [bis(morpholin‐4‐yl)(pentafluoroethyl)phosphane‐κP]pentacarbonylmolybdenum(0) and pentacarbonyl[(pentafluoroethyl)bis(piperidin‐1‐yl)phosphane‐κP]molybdenum(0)

The crystal structures of the title compounds, [Mo{(C₄H₈NO)₂P(C₂F₅)}(CO)₅], (1a), and [Mo{(C₅H₁₀N)₂P(C₂F₅)}(CO)₅], (2a), were determined as part of a larger project that focuses on the synthesis and coordination chemistry of phosphane ligands possessing moderate (electroneutral, i.e. neither electron‐rich nor electron‐deficient) electronic characteristics. Both complexes feature a slightly distorted octahedral geometry at the metal center, due to the electronic and steric repulsions between two of the four equatorial CO groups and the pentafluoroethyl group attached to the phosphane ligand. Bond length and angle data for (1a) and (2a) support the conclusion that the free phosphane ligands are electroneutral. For complex (1a), the Mo—P, Mo—C_ax and Mo—C_eq(ave) bond lengths are 2.5063 (5), 2.018 (2) and 2.048 (2) Å, respectively, and for complex (2a) these values are 2.5274 (5), 2.009 (3) and 2.050 (3) Å, respectively. Geometric data for (1a) and (2a) are compared with similar data reported for analogous Mo(CO)₅ complexes.     

Group 6 metal carbonyl complexes of 3′H-spiro[indole-3,2′-[1,3]benzothiazole-2(1H)]-one

The spiro-compound 3′H-spiro[indole-3,2′-[1,3]benzothiazole-2(1H)-one (IBTH₂) was synthesized and its structure was determined using spectroscopic techniques (FTIR, ¹H NMR and mass) and X-ray crystallography. This ligand possesses different centers for coordination. Reactions of [M(CO)₆], M = Cr, Mo or W with IBTH₂ in THF under reduced pressure were studied. For chromium a complex with molecular formula [Cr(ITP)₂] was isolated; where ITP is the opened form of the ligand which occurred through C_spiro–S bond, while [Mo(CO)₅(IBTH₂)] and [W(CO)₅(IBTH₂)] were isolated from the reaction of IBTH₂ with molybdenum and tungsten carbonyls, respectively. All complexes were characterized by elemental analysis, IR, mass and ¹H NMR spectroscopy. The biological activity of the ligand and its complexes were studied and compared with the parent compound isatin.     

Synthesis and Structures of the Ligands 1‐Methylimidazol‐2‐yl(pyridin‐2‐yl)methanone {(py)(mim)CO} and 1‐Benzylimidazol‐2‐yl(1‐phenylaldimine) (PhN=CHbim) as their Tetracarbonylmolybdenum(0) Complexes [Mo(CO)4(L2‐N,N′)]

The complexes [Mo(CO)₄(L₂‐N,N′)] [L₂ = 1‐methylimidazol‐2‐yl(pyridin‐2‐yl)methanone and 1‐benzylimidazol‐2‐yl(1‐phenylaldimine)] have been synthesized from hexacarbonylmolybdenum(0) in order to define the coordination characteristics of the bidentate nitrogen‐donor ligands; the complexes exhibit distorted octahedral coordination for molybdenum(0) and cis‐bidentate ligand configurations.     

Synthese und spektroskopische Eigenschaften neuer komplexierter Triphosphane

Synthesis and Spectroscopy of new Triphosphine Complexes The reaction of PCl₃ with [HPPh₂W(CO)₅] in the presence of NEt₃ affords stepwise the diand triphosphine complexes [Cl₂PPPh₂W(CO)₅] and ClP[PPh₂W(CO)₅]. Triphosphine complexes of the type [{M′(CO)₅}(H)P{PPh₂M(CO)₅}] (M = M′ = Cr or Mo) are not formed from the reaction of HP[PPh₂M(CO)₅] with [M′(CO)₅thf]. However they were prepared by reaction of [M′(CO)₅PCl₃] with Li[PPh₂M(CO)₅]. The products were characterized by NMR, IR spectroscopy, and mass spectrometry.     

Basicity of transiton metal carbonyl complexes : XIII. Reactions of the π-cyclopentadienyl complexes of molybdenum and tungsten with aprotic acids

The aprotic acids HgCl₂ and SnX₄ (X  Cl, Br) react with the π-complexes C₅H₅M(CO)(NO)(L) (II, M  Mo W; L  PPh₃) by attack at the metal center. With HgCl₂ complexes II yield stable neutral 1:1 adducts CpM(CO)(NO)(L)HgCl₂(III). In the case of SnCl₄, complexes II initially produce the ionic 1:2 adducts [CpM(CO)(NO)(L)(SnCl₃)]⁺SnCl₅^-(IV) which, as a result of oxidative elimination of CO, turn into the neutral complexes CpM(NO)(L)(SnCl₃)(Cl)(V). In reactions of II with SnBr₄ the corresponding CpM(NO)(L)(SnB₃)(Br) complexes are formed directly. The formation of III–V is accompanied by a considerable increase of the frequencies ν(CO) and ν(NO). The structures of the complexes IV (M  Mo) and V (M  Mo) have been established by an X-ray structure analysis.