Crystal Structures Of 2b Research Articles

Versatility in the mode of coordination {(N), (N,O) −, (C,N) − or (C,N,O) 2−} of [(η 5-C 5H 5)Fe{(η 5-C 5H 4)–CH [dbnd]N–(C 6H 4-2OH)}] to palladium(II)

The study of the reactivity of the ferrocenyliminoalcohol [(η 5-C 5H 5)Fe{(η 5-C 5H 4)–CH N–(C 6H 4-2OH)}] ( 1b) with Na 2[PdCl 4] or Pd(OAc) 2 has allowed the isolation and characterization of the heterotrimetallic complexes: trans-[Pd{(η 5-C 5H 5)Fe[(η 5-C 5H 4)–CH N–(C 6H 4-2OH)]} 2Cl 2] ( 2b), [Pd{[(η 5-C 5H 3)–CH N–(C 6H 4-2O)]Fe(η 5-C 5H 5)}{(η 5-C 5H 5)Fe[(η 5-C 5H 4)–CH N–(C 6H 4-2OH)]}] ( 3b) and trans-[Pd{(η 5-C 5H 5)Fe[(η 5-C 5H 4)–CH N–(C 6H 4-2O)]} 2] ( 4b). Ligand 1b acts as a (N) (in 2b) or a (N,O) − (in 4b) ligand; while in 3b the two units of the iminoalcohol exhibit simultaneously different modes of binding {(N) and [C(sp 2, ferrocene),N,O] 2−}. The crystal structures of 2b · 3H 2O and 3b · 1/2CHCl 3 are also reported and confirm the mode of binding of the ligand in these compounds. The relative importance of the factors affecting the preferential formation of products ( 2b– 4b) is also discussed. The study of the reactivity of 3b with PPh 3 has enabled the obtention of the cyclopalladated complexes [Pd{[(η 5-C 5H 3)–CH N–(C 6H 4-2O)]Fe(η 5- C 5H 5)}(PPh 3)] ( 6b) and [Pd{[(η 5-C 5H 3)–CH N–(C 6H 4-2OH)]Fe(η 5-C 5H 5)}Cl(PPh 3)] ( 7b), in which 1b behaves as a [C(sp 2, ferrocene),N,O] 2− (in 6b) or [C(sp 2, ferrocene),N] − (in 7b) ligand. Treatment of 3b with MeO 2C–C C–CO 2Me produces [Pd{[(MeO 2C–C C–CO 2Me) 2(η 5-C 5H 3)–CH N–(C 6H 4-2O)]Fe(η 5-C 5H 5)}] ( 8b), that arises from the bis(insertion) of the alkyne into the σ[Pd–C(sp 2, ferrocene)] bond. The comparison of the results obtained for 1b and [C 6H 5–CH N–(C 6H 4-2OH)] ( 1a) has allowed to establish the influence of the substituents on the imine carbon on their reactivity in front of palladium(II) as well as on the lability of the Pd-ligands bond. 57Fe Mössbauer studies of 2b– 4b and 6b provide conclusive evidence of the effect induced by the mode of binding of 1b on the environment of the iron(II).

Discovery of a new class of 4-anilinopyrimidines as potent c-Jun N-terminal kinase inhibitors: Synthesis and SAR studies

A new series of 4-anilinopyrimidines has been synthesized and evaluated as JNK1 inhibitors. SAR studies led to the discovery of potent JNK1 inhibitors with good enzymatic activity as well as cellular potency represented by compound 2b. Kinase selectivity profile and the crystal structure of 2b are also described.

Chiral Platinum(II) Compounds Containing Ferrocenyl Schiff Bases Acting as (N), (N,O)–, [C(sp2,ferrocene),N]– or [C(sp2,ferrocene),N,O]2– Ligands

AbstractA study of the reactions of the following ferrocenyl Schiff bases: (SC)‐(+)‐[FcCH=NCH(R1)CH2OH] {Fc = (η5‐C5H5)Fe(η5‐C5H4), R1 = Me (1a) or CHMe2 (1b)} with cis‐[PtCl2(dmso)2] under different experimental conditions is reported. This study enabled the isolation and characterisation of the enantiomerically pure platinum(II) complexes trans‐(SC)‐[Pt{FcCH=NCH(R1)CH2OH}Cl2(dmso)] {R1 = Me (2a)or CHMe2 (2b)} and cis‐(SC)‐[Pt{FcCH=NCH(R1)CH2OH}Cl2(dmso)] {R1 = Me (3a) or CHMe2 (3b)} as well as four isomeric forms of (SC)‐[Pt{FcCH=N–CH(R1)CH2O}Cl(dmso)] {R1 = Me or CHMe2} (4–7a,b). These isomers differ in the conformation of the imine {anti‐(E) (in 4 and 6) or syn‐(Z) (in 5 and 7)} or in the relative arrangement of the nitrogen and the dmso group {trans (in 4 and 5) or cis (in 6 and 7)}. Imines 1 behave as a N‐donor ligand in 2 and 3 and as a (N,O)– group in 4–7. We also prepared the diastereomers {(Sp,SC) and (Rp,SC)} of the platinacycles [Pt{[(η5‐C5H3)CH=NCH(R1)CH2OH]Fe(η5‐C5H5)}Cl(dmso)] {8 and 9; R1 = Me (Sp,SC) (8a) and (Rp,SC) (9a) or R1 = CHMe2 (Sp,SC) (8b) and (Rp,SC) (9b)}, [Pt{[(η5‐C5H3)CH=NCH(R1)CH2O]Fe(η5‐C5H5)}(dmso)] {10 and 11; R1 = Me (Sp,SC) (10a) and (Rp,SC) (11a) or R1 = CHMe2 (Sp,SC) (10b) and (Rp,SC) (11b)} and [Pt{[(η5‐C5H3)CH=NCH(R1)CH2OH]Fe(η5‐C5H5)}Cl(PPh3)] {12 and 13; R1 = Me (Sp,SC) (12a) and (Rp,SC) (13a) or R1 = CHMe2 (Sp,SC) (12b) and (Rp,SC) (13b)}, containing a [C(sp2,ferrocene),N]– (in 8, 9, 12 and 13) or a [C(sp2,ferrocene),N,O]2– (in 10 and 11) group. The X‐ray crystal structures of 1b·H2O, 3b, 7b·CH2Cl2·1/2H2O and 9a are also reported. Our study allows the elucidation of the factors affecting the preferential formation of a given platinum(II) complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Syntheses and Structures of [M{In(SC{O}Ph)4}2] (M = Mg and Ca): Single Molecular Precursors to MIn2S4 Materials

The compounds [Mg{In(SC{O}Ph)4}2] (1) and [Ca(H2O)x{In(SC{O}Ph)4}2].yH2O (x = 0, y = 1, 2 major product; x = 1, y = 0, 2a minor product; x = 2, y = 2, 2b minor product) have been synthesized by reacting InCl3 and M(SC{O}Ph)2 (M = Mg and Ca) prepared in situ in the molar ratio 1:2. The structures of 1, 2a, and 2b have been determined by X-ray crystallography. The structure of 1 consists of two tetrahedral [In(SC{O}Ph)4]- anions sandwiching the Mg(II) metal ions through six carbonyl O atoms. The coordination geometry at the Mg(II) metal atom is distorted octahedral with an O(6) donor set. The structures of 2a and 2b consist of two [In(SC{O}Ph)4]- anions sandwiching the Ca(II) metal ion through five and four carbonyl O atoms, and the octahedral coordination at the Ca(II) centers is completed by one and two aqua ligands, respectively. Two aqua ligands and two lattice water molecules form a H-bonded water chain in the channel created by [Ca{In(SC{O}Ph)4}2] molecules in the crystal structure of 2b. The thermal decomposition of 1 and 2 indicated the formation of the corresponding MIn2S4 materials, and this was confirmed by X-ray powder diffraction patterns.

Synthesis, Structures, and Olefin Polymerization Capability of Vanadium(4+) Imido Compounds with fac-N3 Donor Ligands

One-pot reactions of V(NMe2)4 with a range of primary alkyl- and arylamines RNH2 and Me3SiCl afforded the corresponding five-coordinate vanadium(4+) imido compounds V(NR)Cl2(NHMe2)2 [R = 2,6-C6H3(i)Pr2 (1a, previously reported), 2-C6H4(t)Bu (1b), 2-C6H4CF3 (1c), (t)Bu (1d), Ad (Ad = adamantyl, 1e)]. The crystal structures of 1b (two diamorphic forms) and 1c featured N-H...Cl hydrogen-bonded chains. Reaction of 1a-e with the neutral face-capping, N3 donor ligands TACN (TACN = 1,4,7-trimethyltriazacyclononane) or TPM [TPM = tris(3,5-dimethylpyrazolyl)methane] gave the corresponding six-coordinate complexes V(NR)(TACN)Cl2 (2a-e) and V(NR)(TPM)Cl2 (3a-e). The X-ray structures of 2b, 2c, 2d, 3b, 3c, and 3e were determined. When activated with methylaluminoxane, certain of the complexes V(NR)(TPM)Cl2 (3) formed moderately active ethylene polymerization catalysts, whereas none of the compounds V(NR)(TACN)Cl2 (2) were active.

New Rh derivatives of s-indacene active in dehydrogenative silylation of styrene

The mono- and bimetallic complexes [(2,6-diethyl-4,8-dimethyl- s-indacenide){Rh(COD)}] ( 1), anti-[(2,6-diethyl-4,8-dimethyl- s-indacenediide){Rh(COD)} 2] ( 2a), syn-[(2,6-diethyl-4,8-dimethyl- s-indacenediide){Rh(COD)} 2] ( 2b) were synthesized and characterized spectroscopically and in the case of complex 2b, by means of X-ray diffraction. The 13C and 103Rh NMR studies suggest that the bonding mode of the indacenediide ligand can be described as intermediate between η 3- and η 5-coordination. This result was confirmed by the crystal structure of 2b as evidenced by the slippage of the rhodium atom towards the periphery of the ligand. Cyclic voltammetry studies revealed a strong intermetallic communication through the fused ring ligand. This property was further illustrated by higher activity and selectivity of binuclear complexes 2 for the catalytic dehydrogenative silylation of styrene.

(Fluoren-9-ylidene)methanedithiolato Complexes of Platinum: Synthesis, Reactivity, and Luminescence1

Platinum(II) complexes with (fluoren-9-ylidene)methanedithiolato and its 2,7-di-tert-butyl- and 2,7-dimethoxy-substituted analogues were obtained by reacting different chloroplatinum(II) precursors with the piperidinium dithioates (pipH)[(2,7-R2C12H6)CHCS2] [R = H (1a), t-Bu (1b), or OMe (1c)] in the presence of piperidine. The anionic complexes Q2[Pt{S(2)C=C(C12H6R(2)-2,7)}2] [R = H, (Pr(4)N)(2)2a; R = t-Bu, (Pr4N)(2)2b, (Et4N)(2)2b; R = OMe, (Pr4N)(2)2c] were prepared from PtCl(2), piperidine, the corresponding QCl salt, and 1a-c in molar ratio 1:2:2:2. In the absence of QCl, the complexes (pipH)(2)2b and [Pt(pip)(4)]2b were isolated depending on the PtCl(2):pip molar ratio. The neutral complexes [Pt{S2C=C(C12H6R(2)-2,7)L(2)] [L = PPh(3), R = H (3a), t-Bu (3b), OMe (3c); L = PEt(3), R = H (4a), t-Bu (4b), OMe (4c); L(2) = dbbpy, R = H (5a), t-Bu (5b), OMe (5c) (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridyl)] were similarly prepared from the corresponding precursors [PtCl2L2] and 1a-c in the presence of piperidine. Oxidation of Q(2)2b with [FeCp2]PF6 afforded the mixed Pt(II)-Pt(IV) complex Q2[Pt2{S2C=C[C12H6(t-Bu)(2)-2,7]}4] (Q(2)6, Q = Et4N+, Pr4N+). The protonation of (Pr4N)(2)2b with 2 equiv of triflic acid gave the neutral dithioato complex [Pt2{S2CCH[C12H6(t-Bu)(2)-2,7]}4] (7). The same reaction in 1:1 molar ratio gave the mixed dithiolato/dithioato complex Pr4N[Pt{S2C=C[C12H6(t-Bu)(2)-2,7]}{S2CCH[C12H6(t-Bu)(2)-2,7]}] (Pr(4)N8) while the corresponding DMANH+ salt was obtained by treating 7 with 2 equiv of 1,8-bis(dimethylamino)naphthalene (DMAN). The crystal structures of 3b and 5c.CH2Cl2 have been solved by X-ray crystallography. All the platinum complexes are photoluminescent at 77 K in CH2Cl2 or KBr matrix, except for Q(2)6. Compounds 5a-c and Q8 show room-temperature luminescence in fluid solution. The electronic absorption and emission spectra of the dithiolato complexes reveal charge-transfer absorption and emission energies which are significantly lower than those of analogous platinum complexes with previously described 1,1-ethylenedithiolato ligands and in most cases compare well to those of 1,2-dithiolene complexes.

Formation of C–C Bonds in Diiron Complexes by Addition of Carbanions to Alkynyl(methoxy)carbene Ligands

AbstractAddition of cyanide ions to the alkynyl(methoxy)carbene complexes [Fe2{μ‐CN(Me)(R)}(μ‐CO)(CO){Cα(OMe)Cβ≡CγR'}(Cp)2]+ (R = Xyl, R' = Tol, 1a; R = Xyl, R' = Ph, 1b; R = Xyl, R' = Me3Si, 1c; R = Me, R' = Tol, 1d; R = Me, R' = Ph, 1e) occurs selectively at Cα to afford the 1,1‐disubstituted σ‐propargyl complexes [Fe2{μ‐CN(Me)(R)}(μ‐CO)(CO){C(OMe)(CN)(C≡CR')}(Cp)2] (R = Xyl, R' = Tol, 2a; R = Xyl, R' = Ph, 2b; R = Xyl, R' = Me3Si, 2c; R = Me, R' = Tol, 2d; R = Me,R' = Ph, 2e). Conversely, the stabilised carbanaions[CH(R)2]– (R = CN, CO2Me) add at the Cγ position with subsequent hydrogen migration to Cβ to give the 1‐σ‐buta‐1,3‐dienyl complexes [Fe2{μ‐CN(Me)(Xyl)}(μ‐CO)(CO){Cα(OMe)=CβHCγ(Tol)=Cδ(R)2}(Cp)2] (R = CN, 3a; CO2Me, 3b). No migration is possible in the absence of hydrogen atoms at Cδ, therefore addition of [C(Me)(CO2Me)2]– to 1a results in the formation of the σ‐allenyl complex [Fe2{μ‐CN(Me)(Xyl)}(μ‐CO)(CO){Cα(OMe)=Cβ=Cγ(Tol)Cδ(Me)(CO2Me)2}(Cp)2] (4). Protonation of the neutral complexes 3b and 4affords the vinyl(methoxy)carbene complexes [Fe2{μ‐CN(Me)(Xyl)}(μ‐CO)(CO){Cα(OMe)CβH=Cγ(Tol)Cδ(R)(CO2Me)2}]+ (R = H, 5; Me, 6), which exist in solution as mixtures of (E)‐ and (Z)‐isomers in dynamic equilibrium, as shown by VT NMR studies. The cationic complex 6 shows electrophilic behaviour. Thus, addition of CN– results in the σ‐allyl complex [Fe2{μ‐CN(Me)(Xyl)}(μ‐CO)(CO){Cα(OMe)(CN)[CβH=Cγ(Tol)Cδ(Me)(CO2Me)2]}(Cp)2] (7), whereas the reaction with Me2NH affords the vinyl acyl complex [Fe2{μ‐CN(Me)(Xyl)}(μ‐CO)(CO){Cα(O)CβH=Cγ(Tol)Cδ(Me)(CO2Me)2}(Cp)2] (8). The crystal structures of 2b and 3a·CH2Cl2 have been determined. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Cyclometallation of phenylhydrazones: Synthesis, reactivity, crystal structure analysis and novel trinuclear palladium(II) cyclometallated compounds with [C, N, N′] terdentate ligands

Reaction of the ligand C 6H 5N(H)N CMe(C 5H 4N) ( a) with palladium(II) acetate in toluene gave the mononuclear cyclometallated complex [Pd{C 6H 4N(H)N CMe(C 5H 4N)}(AcO)] ( 1a). Reaction of 1a with sodium chloride gave the analogous chlorine compound [Pd{C 6H 4N(H)N CMe(C 5H 4N)}(Cl)] ( 3a) which could also be prepared by reaction of a with lithium tetrachloropalladate and sodium acetate in methanol for 48 h; whereas shorter reaction times afforded the non-cyclometallated complex [Pd{C 6H 5N(H)N CMe(C 5H 4N)}(Cl) 2] ( 2a). Reaction of the ligand 2-ClC 6H 4N(H)N CMe(C 5H 4N) · HCl ( b), with palladium(II) acetate, or with lithium tetrachloropalladate and sodium acetate, yielded the cyclometallated complex [Pd2-ClC 6H 3N(H)N CMe(C 5H 4N)(Cl)] ( 1b). Treatment of 3a and 1b with silver trifluoromethanesulphonate (triflate) and triphenylphosphine in acetone gave the mononuclear complexes [Pd{2-RC 6H n N(H)N CMe(C 5H 4N)}(PPh 3)][CF 3SO 3], (R = H, n = 4, 4a; R = Cl, n = 3, 2b) with the ligand as C,N,N′ terdentate and substitution of chlorine by triphenylphosphine. Reaction of 3a and 1b with silver triflate and the tertiary diphosphine Ph 2P(CH 2) 4PPh 2 (dppb) in a 2:1 molar ratio gave the dinuclear cyclometallated complexes [{Pd[2-RC 6H 3N(H)N CMe(C 5H 4N)]} 2(μ-Ph 2P(CH 2) 4PPh 2)][CF 3SO 3] 2 (R = H, 5a; R = Cl, 3b) with a μ 2-diphosphine bridging ligand. Similarly, treatment of 3a and 1b with silver triflate and the tertiary triphosphines MeC(CH 2PPh 2) 3 (tripod) and (Ph 2PCH 2CH 2) 2PPh (triphos), in 3:1 molar ratio, gave the novel trinuclear complexes [{Pd[C 6H 4N(H)N CMe(C 5H 4N)]} 3{μ 3-MeC(CH 2Ph 2) 3}][CF 3SO 3] 3 ( 6a) and [{Pd[2-ClC 6H 3N(H)N CMe(C 5H 4N)]} 3{μ 3-(PPh 2CH 2CH 2) 2PPh}][CF 3SO 3] 3 ( 4b) regioselectively, with the phosphine as a μ 3-bridging ligand. When the reaction between 3a and triphos was carried out in 1:1 molar ratio the mononuclear complex [Pd{C 6H 4N(H)N CMe(C 5H 4N)}{(PPh 2CH 2CH 2) 2PPh-P,P,P}][ClO 4] ( 7a) was obtained. The crystal structures of 2b, 3a and 4a have been determined by X-ray crystallography.

Difluorenylsilanes, -germanes, and -stannanes Exhibiting an Unprecedented Parallel Arrangement of the Fluorene Units

New, yet unprecedented molecular structures with parallel fluorene units were found by X-ray diffraction in (9,9'-disubstituted difluorenyl)(dimethyl) derivatives of group 14 elements Me 2 E(CR'R 2 )(CRR 2 ) (E = Si, R' = Me, R = SiMe 3 , 6a; E = Ge, R' = Me, R = SiMe 3 , 6b; and E = Sn, R' = R = SiMe 3 , 5c; CR 2 = fluorene units). This is in sharp contrast with the structure of monosubstituted Me 2 Ge(CHR 2 )(CR 2 -SiMe 3 ) (3b) and disubstituted Me 2 E(CMeR 2 ) 2 (E = Ge, 4b; E = Sn, 4c) derivatives where the two fluorene units are almost perpendicular. Intramolecular C-H...π interactions are revealed by solution 1 H NMR spectroscopy and supported by the AM1 molecular orbital calculations. Intermolecular (aryl, alkyl)C-H...π interactions leading to supramolecular associations are shown by the crystal structures of 3b, 4b, 4c, 5c, and 6a. In 4b and 5c rather unusual CH...HC distances resembling the dihydrogen bonds are noticed. Synthesis, NMR spectra, and gas phase conformations predicted on the basis of AM1 semiempirical molecular orbital calculations are discussed for Me 2 E(CRR 2 )(CRR 2 ) (E = Si, R' = R = SiMe 3 , 5a; E = Ge, R' = R = SiMe 3 , 5b; E = Sn, R' = H, R = Me, 2c; R' = H, R = SiMe 3 , 3c; R' = Me, R = SiMe 3 , 6c; CR 2 = fluorene units).

Methanetriacetic and methylmethanetriacetic acids, their precursors and derivatives: NMR and X-ray diffraction studies

The NMR spectra and crystal structures of triacid 2b, triamide 4b and diastereomers 7, 8 were studied; the crystal structure of 2b is the first example of an H-bonded totally interlocked and percatenated homochiral structure.

Synthesis and characterization ofN,N-diethyldithiocarbamate complexes of 2-alkoxycarbonylethyltin trichloride

N,N-Diethyldithiocarbamate complexes of 2-alkoxycarbonylethyltin trichloride, ROCOCH 2 CH 2 SnCl 3-x [S 2 CNEt 2 ] x (R = CH 3 (a); CH 3 CH 2 (b); CH 2 =CHCH 2 (c); CH 3 CH 2 CH 2 (d); CH 3 CH 2 CH 2 CH 2 (e); x = 1 (1), 2 (2)) were synthesized and characterized by means of elemental analysis, IR, and NMR ( 1 H, 13 C and 119 Sn) spectra. The crystal structure of 1b (i.e. R = CH 3 CH 2 , x =1) was determined and shows that the tin atom adopts a distorted octahedral geometry with both a five-membered chelate ring, formed via carbonyl coordination to tin, and a four-membered chelate ring, formed by the bidentate dithiocarbamate. The spectral data and ab initio calculations indicate that intramolecular carbonyl-oxygen to tin coordination in 1a-1e persists, but not in 2a-2e, owing to the preference of the dithiocarbamate ligands to chelate the tin centre.

Highly reactive oligosilyltriflates—synthesis, structure and rearrangement

The novel branched oligosilyltriflates of formula [TfO(Me3Si)2Si]2E (2a–d) [E = 0 (2a), SiMe2 (2b), GeMe2 (2c), SiMe2–SiMe2 (2d)] and [TfO(Me3Si)2SiSiMe2]3SiMe (9) have been prepared by the protodesilylation of [Ph(Me3Si)2Si]2E (1a–c), [H(Me3Si)2Si]2E (5d) and [Ph(Me3Si)2SiSiMe2]3SiMe (8) using TfOH (CF3SO3H) as reagent in almost quantitative yields. The crystal structure of 2b is reported.

The synthesis, structure and ethene polymerisation catalysis of mono(salicylaldiminato) titanium and zirconium complexes

The silyl ethers 3-But-2-(OSiMe3)C6H3CH=NR (2a-e) have been prepared by deprotonation of the known iminophenols (1a-e) and treatment with SiClMe3 (a, R = C6H5; b, R = 2,6-Pri2C6H3; c, R = 2,4,6-Me3C6H2; d, R = 2-C6H5C6H4; e, R = C6F5). 2a-c react with TiCl4 in hydrocarbon solvents to give the binuclear complexes [Ti{3-But-2-(O)C6H3CH=N(R)}Cl(mu-Cl3)TiCl3] (3a-c). The pentafluorophenyl species 2e reacts with TiCl4 to give the known complex Ti{3-But-2-(O)C6H3CH=N(R)}2Cl2. The mononuclear five-coordinate complex, Ti{3-But-2-(O)C6H3CH=N(2,4,6-Me3C6H2)}Cl3 (4c), was isolated after repeated recrystallisation of 3c. Performing the dehalosilylation reaction in the presence of tetrahydrofuran yields the octahedral, mononuclear complexes Ti{3-But-2-(O)C6H3CH=N(R)}Cl3(THF) (5a-e). The reaction with ZrCl4(THF)2 proceeds similarly to give complexes Zr{3-But-2-(O)C6H3CH=N(R)}Cl3(THF) (6b-e). The crystal structures of 3b, 4c, 5a, 5c, 5e, 6b, 6d, 6e and the salicylaldehyde titanium complex Ti{3-But-2-(O)C6H3CH=O}Cl3(THF) (7) have been determined. Activation of complexes 5a-e and 6b-e with MAO in an ethene saturated toluene solution gives polyethylene with at best high activity depending on the imine substituent.

Synthesis and characterization of cationic and zwitterionic allyl zirconium complexes derived from trimethylenemethane (TMM) cyclopentadienylzirconium acetamidinates

Protonation of the trimethylenemethane derivatives, Cp*Zr(σ 2,π-C 4H 6)[N(R 1)C(Me)N(R 2)] ( 1a: R 1=R 2= i-Pr and 1b: R 1=Et, R 2= t-Bu) (Cp*=η 5-C 5Me 5), by [PhNMe 2H][B(C 6F 5) 4] in chlorobenzene at −10 °C provides the cationic methallyl complexes, Cp*Zr(η 3-C 4H 7)[N(R 1)C(Me)N(R 2)] ( 2a: R 1=R 2= i-Pr and 2b: R 1=Et, R 2= t-Bu), which are thermally robust in solution at elevated temperatures as determined by 1H NMR spectroscopy. Addition of B(C 6F 5) 3 to 1a and 1b provides the zwitterionic allyl complexes, Cp*Zr{η 3-CH 2C[CH 2B(C 6F 5) 3]CH 2}[N(R 1)C(Me)N(R 2)] ( 3a: R 1=R 2= i-Pr and 3b: R 1=Et, R 2= t-Bu). The crystal structures of 2b and 3a have been determined. Neither the cationic complexes 2 or the zwitterionic complexes 3 are active initiators for the Ziegler-Natta polymerization of ethylene and α-olefins.

1,1-ethylenedithiolato complexes of palladium(II) and platinum(II) with isocyanide and carbene ligands.

The reactions of [Tl(2)[S(2)C=C[C(O)Me](2)]](n) with [MCl(2)(NCPh)(2)] and CNR (1:1:2) give complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)(2)] [R = (t)Bu, M = Pd (1a), Pt (1b); R = C(6)H(3)Me(2)-2,6 (Xy), M = Pd (2a), Pt (2b)]. Compound 1b reacts with AgClO(4) (1:1) to give [[Pt(CN(t)Bu)(2)](2)Ag(2)[mu(2),eta(2)-(S,S')-[S(2)C=C[C(O)Me](2)](2)]](ClO(4))(2) (3). The reactions of 1 or 2 with diethylamine give mixed isocyanide carbene complexes [M[eta(2)-S(2)C=C[C(O)Me](2)](CNR)[C(NEt(2))(NHR)]] [R = (t)Bu, M = Pd (4a), Pt (4b); R = Xy, M = Pd (5a), Pt (5b)] regardless of the molar ratio of the reagents. The same complexes react with an excess of ammonia to give [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)](CN(t)Bu)[C(NH(2))(NH(t)Bu)]] [M = Pd (6a), Pt (6b)] or [M[eta(2)-(S,S')-S(2)C=C[C(O)Me](2)][C(NH(2))(NHXy)](2)] [M = Pd (7a), Pt (7b)] probably depending on steric factors. The crystal structures of 2b, 4a, and 4b have been determined. Compounds 4a and 4b are isostructural. They all display distorted square planar metal environments and chelating planar E,Z-2,2-diacetyl-1,1-ethylenedithiolato ligands that coordinate through the sulfur atoms.

Polymeric, Molecular, and Cation/Anion Arrangements in Chloro‐, Bromo‐, and Iododiruthenium(II,III) Carboxylate Compounds

AbstractThe synthesis and characterization of the anhydrous compounds [Ru2X(μ‐O2CR)4] [R = CH2CH2OPh, X = Cl (1a), Br (2a), I (3a); R = CMePh2, X = Br (5a), I (6a)] and of the solvated complexes [Ru2X(μ‐O2CR)4(H2O)] [R = CH2CH2OPh, X = Cl (1b), I (3b); R = CMePh2, X = Cl (4b), Br (5b), I (6b)] are described. Thermogravimetric analyses have been used to confirm the anhydrous or solvated natures of the complexes. The crystal structures of 1b·2MeOH, 3b·0.5H2O, and 4b have been investigated by X‐ray diffraction and none of them shows the usual polymeric arrangement reported for tetracarboxylatodiruthenium(II,III) compounds. The structure of 3b·0.5H2O consists of cationic and anionic units, [Ru2(μ‐O2CCH2CH2OPh)4(H2O)2][Ru2I2(μ‐O2CCH2CH2OPh)4], and represents the first reported crystal structure of a tetracarboxylato(iodo)diruthenium(II,III) derivative. The structures 1b·2MeOH and 4b each show the presence of discrete dinuclear molecules. The crystal structure of [Ru2Cl(μ‐O2CCMePh2)4(H2O)] demonstrates that diruthenium compounds with the same halide and carboxylate ligands may adopt polymeric or discrete molecular dispositions. Magnetic susceptibility measurements of the complexes in the 2−300 K range have been carried out. Complex 2a shows a strong antiferromagnetic coupling, consistent with the existence of linear chains in the solid state. The complexes [Ru2X(μ‐O2CR)4(H2O)] show weak through‐space antiferromagnetic coupling, in accordance with non‐polymeric structures. The magnetic behaviour of 1a, 3a, 5a, and 6a suggests a mixture of arrangements. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Synthesis, Chemistry, and Structures of Neopentyl and (Trimethylsilyl)methyl Antimony and Bismuth Oligomers

Dehalogenation of RSbBr2 (R = Me3CCH2) with Mg gives cyclo-(RSb)n (n = 4 (1a), 5 (1b)). The compounds cyclo-(RBi)n (R = Me3CCH2; n = 3 (2a), 5 (2b)) form by reaction of RBiCl2 with LiAlH4. Equilibria between 1a and 1b or between 2a and 2b favor the smaller rings at higher temperatures and dilution. Thermal reactions of 2a,b lead to R4Bi2 (3; R = Me3CCH2) and elemental bismuth. Reaction of 2a,b with W(CO)5(thf) (thf = tetrahydrofuran) gives [{μ-η2-cis-(RBi)2}{W(CO)5}2] (4; R = Me3CCH2). Decomposition of [{μ-η2-cis-(R‘Bi)2}{W(CO)5}2] (5; R‘ = Me3SiCH2) leads to [η2-trans-(R‘Bi)2W(CO)5] (6). The crystal structures of 1b, 4, and 6 are reported.

A Comparison of Analogous 4f‐ and 5f‐Element Compounds: Syntheses and X‐ray Crystal Structures of the Mixed Sandwich Complexes [M(η‐C8H8)(L){OP(NMe2)3}] (M = Nd or U; L = η‐C5Me5 or η‐C4Me4P)

AbstractThe series of complexes [M(COT)(L)(HMPA)] {M = Nd or U; COT = η‐C8H8; L = η‐C5Me5 (Cp*) or η‐C4Me4P (tmp), HMPA = OP(NMe2)3} have been synthesized. [Nd(COT)(Cp*)(HMPA)] (1b) was prepared by substitution of the THF ligand of [Nd(COT)(Cp*)(THF)]; [Nd(COT)(tmp)(HMPA)] (3) was prepared by reaction of the neodymium cation [Nd(COT)(THF)4][BPh4] with Ktmp followed by the addition of HMPA to the dimeric compound [Nd(COT)(tmp)]2 (2); [U(COT)(Cp*)(HMPA)] (4) was isolated from the reaction of the uranium cation [U(COT)(HMPA)3][BPh4] with KCp*, and [U(COT)(tmp)(HMPA)2] (5) was obtained upon reduction of the uranium(IV) cation of [U(COT)(tmp)(HMPA)2][BPh4] with sodium amalgam. The X‐ray crystal structures of 1b, 3, and 4 have been determined. In the isostructural compounds 1b and 4, the differences between the U−C and Nd−C bond lengths are smaller than those predicted from the ionic radii of the trivalent ions; in particular, the average M−C(Cp*) distances are equal to 2.77 Å for both M = Nd and U. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Mixed dinitrogen-organocyanamide complexes of molybdenum(0) and their protic conversion into hydrazide and amidoazavinylidene derivatives.

Organocyanamides, Ntbd1;CNR(2) (R = Me or Et), react with trans-[Mo(N(2))(2)(dppe)(2)] (1, dppe = Ph(2)PCH(2)CH(2)PPh(2)), in THF, to give the first mixed molybdenum dinitrogen-cyanamide complexes trans-[Mo(N(2))(NCNR(2))(dppe)(2)] (R = Me 2a or Et 2b) which are selectively protonated at N(2) by HBF(4) to yield the hydrazide(2-) complexes trans-[Mo(NNH(2))(NCNR(2))(dppe)(2)][BF(4)](2) (R = Me, 3a, or Et, 3b). On treatment with Ag[BF(4)], oxidation and metal fluorination occur, and the ligating cyanamide undergoes an unprecedented beta-protonation at the unsaturated C atom to form trans-[MoF(NCHNR(2))(dppe)(2)][BF(4)](2) (R = Me, 4a, or Et, 4b) compounds which present the novel amidoazavinylidene (or amidomethyleneamide) ligands. Complexes 4 are also formed from the corresponding compounds 3, with liberation of ammonia and hydrazine. The crystal structure of 2b was determined by single-crystal X-ray diffraction analysis which indicates that the N atom of the amide group has a trigonal planar geometry.