CH2 NMe2 Research Articles

Ligand oxidation of small-ring aza- and thia-macrocycles involving CH activation: crystal structures of [MeN(CH 2NMe) 2CH] 2[MX 6]·MeCN (M=Te, X=Cl, Br; M=Sn, X=Br and [C 6H 11S 3] 2[TeBr 6]·MeCN)

Reactions of M(IV) halides with the six-membered triazacyclohexane (MeNCH 2) 3 provide the ionic salts [MeN(CH 2NMe) 2CH] 2[MX 6]·MeCN where M=Te, X=Cl ( I); M=Te, X=Br ( II) and M=Sn, X=Br ( III), as confirmed by spectroscopic and single crystal X-ray diffraction studies. The individual [MeN(CH 2NMe) 2CH] + cations contain a planar (Me)NCHN(Me) segment reminiscent of amidinium formation (mean): NC, 1.31(1) Å; NCN, 123.3(1)°. A plausible reaction pathway involving an incipient release of a hydride ion from a CH 2 unit of the bound ligand and a subsequent attack (nucleophilic) at the β-carbon of a coordinated acetonitrile (solvent) molecule is discussed. Supporting evidence for activation of the acetonitrile via a nucleophilic attack comes from the reaction system GeBr 4/ iC 3H 7NHCOCH 2CONH iC 3H 7/CH 3CN, which provides the cationic organohydrobromide salt [CH 3C(CH(CONH iC 3H 7) 2) 2NH 3]Br ( IV). The structure of IV reveals two malonamide fragments attached to the acetonitrile residue. The reaction of TeBr 4 and [9]aneS 3 provides orange crystals of a product identified spectroscopically and by X-ray diffraction studies as the bicyclic sulphonium salt [C 6H 11S 3] 2[TeBr 6]·MeCN ( V). A plausible reaction pathway, namely molecular oxidation with CH activation resulting in hydride ion expulsion, is suggested. The structure of the bicyclic cation reveals a five-membered ring and a six-membered ring fused along a common SC linkage, 1.825(6) Å. The peripheral SC bond distances lie in the range 1.800(5)–1.822(5) Å. The reaction of TeCl 4 and Me 3[9]aneN 3 in toluene gives orange crystals of the doubly-protonated ligand salt [(Me 3[9]aneN 3)H 2][TeCl 6]·C 6H 5CH 3 ( VI). An extensive pattern of intra- and inter-molecular hydrogen bonding is observed.

An approach to heterometallic alkoxide-β-diketonate complexes with a M 4O 4 cubane-like core and new prospects of their application in preparation of solid catalysts. X-ray single crystal study of (Co,Ni) 4(acac) 4(μ 3-OMe) 4(MeOH) 4, Co 2Ni 2(acac) 4(μ 3-OMe) 4(OAc) 2 and Mg 4(acac) 4(μ 3-OMe) 4(MeOH) 4

The interaction of the individual M 4(acac) 4(μ 3-OMe) 4(MeOH) 4 complexes, M=Co, Ni in toluene/methanol media provided crystals of (Co,Ni) 4(acac) 4(μ 3-OMe) 4(MeOH) 4 ( I) — the product of co-crystallization of isomorphous products. The oxidation of a MeOH solution of I in air in the presence of NaOAc and aminoalcohols as catalysts gave Co 2Ni 2(acac) 4(μ 3-OMe) 4(OAc) 2 ( II), an individual heterometallic derivative. The interaction of Mg(OCH(CH 3)CH 2NMe 2) 2 with Cu(acac) 2 in toluene/methanol media produced Mg 4(acac) 4(μ 3-OMe) 4(MeOH) 4 ( III) as the only isolatable product. The starting Co and Ni homometallic complexes as well as the heterometallic CoNi complex II were used to prepare the zeolite-supported oxide catalysts which exhibited extremely high activity towards methanol oxidation.

Synthesis and characterization of platinum(II)-terminated dendritic carbosilanes: X-ray crystal structure of the model species [PtCl(C 6H 3{CH 2NMe 2}-2-SiMe 3-5)(PPh 3)

A series of cycloplatinated carbosilane dendrimers appended with the monoanionic C,N-bidentate ligand [C 6H 4{CH 2NMe 2}-2] − (CN) was prepared via a multiple CH activation reaction. Ligand exchange in the parent model species [PtCl(C 6H 3{CH 2NMe 2}-2-SiMe 3-5)(DMSO)] ( 1) in the presence of PPh 3 gave the phosphine complex [PtCl(C 6H 3{CH 2NMe 2}-2-SiMe 3-5)(PPh 3)] ( 2). The crystal structure of 2 was also determined, showing a close proximity between one of the ArH of the phosphine ligand and the ArH ortho of the CN ligand.

Hypervalent tellurium compounds containing N→Te intramolecular interactions. Crystal and molecular structure of [2-(Me 2NCH 2)C 6H 4] 2Te 2, [2-(Me 2NCH 2)C 6H 4]TeS(S)PR 2 (R=Me, Ph, OPr i) and [2-(Me 2NCH 2)C 6H 4]Te–S–PPh 2N–PPh 2S

[2-(Me 2NCH 2)C 6H 4]TeS(S)PR 2 [R=Me ( 2), Et ( 3), Ph ( 4), OPr i ( 5)] were prepared by reacting [2-(Me 2NCH 2)C 6H 4] 2Te 2 ( 1) with the appropriate disulfanes, [R 2P(S)S] 2, while [2-(Me 2NCH 2)C 6H 4]Te–S–PPh 2N–PPh 2S ( 6) was obtained by metathesis reaction between [2-(Me 2NCH 2)C 6H 4]TeBr and potassium tetraphenyldithioimidodiphosphinate. The compounds were characterized by multinuclear NMR ( 1H, 13C, 31P). The crystal and molecular structures of 1, 2, 4– 6 were determined by single-crystal X-ray diffraction. All compounds are monomeric and the N atom of the pendant CH 2NMe 2 arm is strongly coordinated to the tellurium atom. The organophosphorus ligands are monodentate, thus resulting in a T-shaped coordination geometry around tellurium.

Hypervalent organotin(IV) derivatives containing [2-(Me 2NCH 2)C 6H 4]Sn moieties. Competition between nitrogen and chalcogen atoms for coordination to the metal centre

[2-(Me 2NCH 2)C 6H 4]SnPh 2Cl ( 1) was prepared by reacting Ph 2SnCl 2 with [2-(Me 2NCH 2)C 6H 4]Li in toluene. The reactions of ( 1) with the ammonium salt of the appropriate thiophosphinato ligand in 1:1 molar ratio afford the isolation of [2-(Me 2NCH 2)C 6H 4]SnPh 2L [L=S(S)PPh 2 ( 2), O(S)PPh 2 ( 3)] as white crystalline solids. The molecular structure of 1– 3 was determined by single-crystal X-ray diffraction. Their crystals contain monomeric units with the metal atom exhibiting a distorted trigonal bipyramidal coordination environment. The SnC 3 moiety is almost planar. The N atom of the pending CH 2NMe 2 arm is strongly coordinated to the metal centre (Sn(1)N(1) 2.519(2), 2.548(3), 2.481(2) Å for 1, 2 and 3, respectively), trans to the Cl, O or S atoms (N(1)Sn(1)Cl(1) 170.49(6)°, N(1)Sn(1)S(1) 169.06(8)°, N(1)Sn(1)O(1) 168.58(8)°, respectively). The S atom double bonded to phosphorus is not involved in intra- or intermolecular coordination to tin.

Synthesis and characterisation of four- and eight-membered ring auralactam complexes

The reactions of the cyclo-aurated gold(III) dihalide complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}AuCl 2] with N-cyanoacetylurethane [NCCH 2C(O)NHCO 2Et], 2-benzoylacetanilide [PhC(O)CH 2C(O)NHPh] and acetoacetanilide [MeC(O)CH 2C(O)NHPh], and [{C 6H 4(CH 2NMe 2)-2}AuCl 2] with acetoacetanilide in dichloromethane with excess silver(I) oxide gives the first examples of auralactam complexes, containing AuNRC (O)CHR′ four-membered rings. A single-crystal X-ray diffraction study on the complex [{C 6H 4(CH 2NMe 2)-2}A u{NPhC(O)C H(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl 3 solution of the complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}A u{N(CO 2Et)C(O)C HCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}Au{N(CO 2Et)C(O)CHCN}] 2·2CDCl 3, characterised by an X-ray structure determination. The dimer contains an eight-membered A uNC(O)CAuNC(O)C ring.

Preparation and electrochemical behaviour of dinuclear platinum complexes containing NCN ligands (NCN=[C 6H 3(Me 2NCH 2) 2-2,6] −). The crystal structure of [C 6H 3(Me 2NCH 2) 2-1,3-(CC)-5] 2

A series of homodinuclear Pt compounds containing the anionic, potentially terdentate NCN ligand (NCN=[C 6H 3(Me 2NCH 2) 2-2,6] −) or its 4-ethynyl derivative were prepared. The two platinum centres are linked together in two different fashions: (i) directly linked by an ethynyl or diethynylphenyl group (head-to-head) and (ii) indirectly bonded by a ethynyl- or butadiynyl-linked bis-NCN ligand (tail-to-tail). The reaction of the head-to-head σ,σ′-ethynylide complex {Pt}CC{Pt} ({Pt}=[Pt(C 6H 3{CH 2NMe 2} 2-2,6)] +) with [CuCl] n yields {Pt}Cl and [Cu 2C 2] n , while with [Cu(NCMe) 4][BF 4] a Cu(I) bridged complex was formed: [(η 2-{Pt}CC{Pt}) 2Cu][BF 4]. The results of cyclic voltammetry experiments reveal that both connection modes of the two platinum centres lead to electrochemically independent Pt–NCN units. The X-ray crystal structure analysis of the neutral, tail-to-tail bridging butadiyne bis-NCNH ligand [C 6H 3(CH 2NMe 2)-1,3-(CC)-5] 2 is reported.

Study on structural properties and solution dynamics of zinc complexes with the ( N, N-dimethylaminomethyl)ferrocenyl ligand

The reaction of { C, N-[Fe(η 5-C 5H 5)(η 5-C 5H 3(CH 2NMe 2)-2)]}Li, (FcN)Li, with zinc chloride affords the diorganozinc complex (FcN) 2Zn ( 1). In solution, 1 appears as a mixture of rac and meso diastereomers, whereas in the solid state it crystallizes solely as a rac diastereomer. The ratio of rac/meso diastereomers in solution is solvent-, temperature- and concentration-dependent, consistent with an intermolecular exchange between diastereomers. An intramolecular dynamic phenomenon involving dissociation and recoordination of ZnN bonds was also observed. The reaction of 1 with zinc chloride yields the monoorganozinc compound (FcN)ZnCl ( 2) as a slightly soluble yellow microcrystalline powder.

Donor-funktionalisierte Alkinyle von Titan(IV), Kupfer(I) und Silber(I); Festkörperstrukturen von [Ti](CCCH 2NMe 2) 2 und {[Ti](CC tBu) 2}CuCCCCC 2H 5

The preparation of numerous donor-functionalised acetylides with Ti(IV) and/or Group II transition metals is described. The reaction of [Ti]Cl 2 ( 1) {[Ti]=(η 5-C 5H 4SiMe 3) 2Ti} with two equivalents of LiCCR 1 [ 2a: R 1=CMeCH 2; 2b: R 1=C 6H 4CN-4; 2c: R 1=CH 2NMe 2; 2d: R=C 5H 4N-4] affords the bis(alkynyl)titanocenes [Ti](CCR 1) 2 [ 3a: R 1=CMeCH 2; 3b: R 1=C 6H 4CN-4; 3c: R 1=CH 2NMe 2] in good yields. While by treatment of 1 with 2d in a 1:2 molar ratio only non-characterisable products are formed, the use of [Ti](Cl)(CH 2SiMe 3) ( 4) produces [Ti](CH 2SiMe 3)(CCC 5H 4N-4) ( 5) in excellent yields. Monomeric, donor-functionalised copper(I) acetylides of general type {[Ti](CCR 1) 2}CuCCR 3 [R 1= t Bu, 7a: R 3=CCCH 2CH 3; 7b: R 3=CMeCH 2; 7c: R 3=C 6H 4CN-4; R 1=SiMe 3, 7d: R 3=CMeCH 2; 7e: R 3=C 6H 4CN-4] are accessible by (i) the reaction of {[Ti](CC t Bu) 2}CuSC 6H 4CH 2NMe 2-2 ( 6) with equimolar amounts of 2a– 2c or (ii) treatment of the monomeric copper(I) methyl {[Ti](CCR 1) 2}CuCH 3 ( 8a: R 1=SiMe 3, 8b: R 1= t Bu) with HCCR 3 [ 9a: R 3=CCCH 2CH 3, 9b: R 3=CMeCH 2, 9c: R 3=C 6H 4CN-4] in a 1:1 molar ratio. The reaction chemistry of these complexes towards selected transition metal compounds is described. The bis(alkynyl)titanocenes 3a– 3c produce with ML n { 10a: ML n =CuCl; 10b: ML n =CuI; 10c: ML n =[Cu(CH 3CN) 4][PF 6]; 10d: ML n =AgBF 4; 10e: ML n =Ni(CO) 4} the heterobimetallic tweezer complexes {[Ti](CCR 1) 2}ML [R 1=CMeCH 2; 11a: ML=CuCl; R 1=C 6H 4CN-4; 11b: ML=CuCl; 11c: ML=CuI; 11d: ML=Ni(CO); R 1=CH 2NMe 2; 11e: ML=CuPF 6; 11f: ML=AgBF 4]. In complexes 11a– 11f an early and a late transition metal centre [e.g. Ni(0)] are linked via the corresponding R 1CC ligands of the organometallic π-tweezer complexes. For complexes 11e and 11f a dynamic behaviour is observed in solution. The solid state structures of 3c and 7a are reported. Both compounds crystallise in the triclinic space group P 1 ̄ . They exhibit features that are characteristic for this class of complexes: (i) a tetrahedral environment around the Ti(IV) of 3c and 7a, (ii) a lengthening of the CC triple bonds upon η 2-coordination to the transition metal complex fragment CuCCCCC 2H 5, (iii) a trans-deformation of the TiCC t Bu unit, and (iv) a reduction of the bite angle C CCTiC CC for 7a.

New Group 9 metal complexes containing N, P-chelate ligand system. : Synthesis, characterization and application to catalytic hydrogenation

New N, P-chelating o-carboranylaminophosphine ligand Cab N, P 2 [Cab N, P = o-C 2B 10H 10(CH 2NMe 2)(PPh 2)- N, P] was prepared from o-carboranylamine LiCab N [Cab N = o-C 2B 10H 10(CH 2NMe 2)- N] and chlorodiphenylphosphine. Consequently, the reaction of [M(cod)(solv) 2] +BF 4 − (M=Rh, Ir; cod=cycloocta-1,5-diene) with 2 was investigated. The resulting rhodium and iridium metal complexes [(Cab N, P )M(cod)] +BF 4 − 3 (M=Rh 3a, Ir 3b) were characterized by NMR spectroscopy and elemental analysis. In addition, an X-ray structure analysis was performed on complex 3a, where the potential N, P-chelate ligand 2 was found to coordinate in a bidentate mode. The subsequent reaction of 3 with PPh 3 and CO resulted in the dissociation of the N, P-chelate ligand 2 to yield the penta-coordinate metal complexes [(PPh 3) 2M(CO) 3] +BF 4 − 4 (M=Rh 4a, Ir 4b). The structure of 4a was determined by X-ray diffraction analysis, exhibiting a trigonal bipyramidal configuration with the triphenylphosphine ligands occupying axial positions. The activities of complex 3 as a catalyst precursor during the hydrogenation of cyclohexene were tested and produced the cyclohexane with 100% conversion in the case of 3a.

O, N-Chelated boron aminophenolate complexes. Crystal structure of BPh 2(OC 6H 4(CH 2NMe 2)-2)

Two diphenylboron ortho-aminophenolate complexes, [BPh 2(OC 6H 4(CH 2NMe 2)-2)] ( 2) and [BPh 2(OC 6H 2(CH 2NMe 2) 2-2,6-Me-4)] ( 6), have been prepared in a one-pot procedure approach starting from B(OMe) 3. The starting material was reacted with two equivalents of phenylmagnesium bromide, followed by hydrolysis with HCl. The resulting borinic acid, BPh 2(OH), was reacted with either HOC 6H 4(CH 2NMe 2)-2 or HOC 6H 2(CH 2NMe 2) 2-2,6-Me-4 to give 2 or 6, respectively. An X-ray structure determination of 2 showed it to be a four-coordinate boron compound with a tetrahedral coordination geometry. The six-membered chelate ring in 2 is puckered. Variable temperature 1H-NMR analysis of 6 showed the existence of two dynamic processes in solution, i.e. one process involving flipping of the puckered chelate ring conformation (Δ G ‡=41 kJ mol −1) and a second, higher energy, process (Δ G ‡=65 kJ mol −1) in which exchange of coordinated and non-coordinated amine functions occurs. The exchange is (at least partly) assisted intermolecularly.

Reactivity of Cyclocobaltated Benzylamine Derivatives toward Terminal Alkynes

The cyclocobaltated complexes [(η5-C5H5)Co(4-RC6H3CH2NMe2-C2,N)I] (1; R = H, Me, F) reacted with terminal alkynes such as R‘C⋮CH (2; R‘ = tBu, SiMe3) to afford a mixture of the two compounds {(η5-C5H5)Co[η5-C5H4CHCR‘(4-R-2-(CH2NMe2)C6H3)]}+PF6- (3) and (E)-CHR‘CH(4-R-2-(CH2NMe2)C6H3) (4) in a ca. 1:1 ratio. The reaction is rationalized by assuming that insertion of the alkyne into the Co−C bond of 1 occurred with no regioselectivity, leading to two unstable regioisomers; a selective migration of the less hindered alkenyl−Co derivative to a Cp unit followed by migration of the monosubstituted Cp ring thus obtained to another cobalt center afforded 3, whereas compound 4 should be obtained via protiodemetalation of the other isomer formed.

Perilithiation and the synthesis of 8-substituted-1-naphthamides

Attempted perilithiation of 1-naphthamides with their 2-positions blocked leads only to nucleophilic attack on the aromatic ring, but perilithiation of naphthalenes bearing 1-substituents such as -NMe 2 or -CH 2NMe 2 allows the synthesis of 8-substituted-1-naphthamides. The 8-CH 2NMe 2 substituents can be converted to carbonyl groups by Polonovski reactions; other 8-substituents may be introduced by using naphthalic anhydride as a starting material.

Spirocyclic stannole derivatives by 1,1-organoboration of 2,2-bis(1-alkynyl)-1,3-di-tert-butyl-1,3,2-diazastannacyclohexanes

With the exception of 1c, the 2,2-bis(1-alkynyl)-1,3-di-tert-butyl-1,3,2-diazastannacyclohexanes ( 1) [CCR 1: R 1=Me ( a), Bu ( b), tBu ( c), Ph ( d), SiMe 3 ( e), CH 2NMe 2 ( f), CH 2OMe ( g)] react with triethylborane, Et 3B ( 2), to give the spirocyclic stannole derivatives 4a, b, d, e, f, g by intermolecular 1,1-ethylboration, followed by intramolecular 1,1-vinylboration. In the cases of 1f and 1g, zwitterionic intermediates 7f, g, in which the tin atom is coordinated to an alkynylborate CC bond, were detected by NMR spectroscopy. In the case of the reaction of 1e with triphenylborane, Ph 3B ( 3), exchange reactions involving the SnN bonds compete with 1,1-organoboration, and the spirocyclic stannole derivative 5e is only part of a complex reaction mixture. In the reaction of 1e with Et 3B, an intermediate 8e with the wrong stereochemistry for ring closure was detected by NMR spectroscopy. Owing to the reversibility of 1,1-organoboration, the spirocyclic stannole 4e is finally formed. Products and intermediates were characterised by 1H, 11B, 13C, 15N, 29Si and 119Sn NMR spectroscopy. Several absolute signs of coupling constants in 4e were determined.

C–H activation of a MeN grouping in one of the CH 2NMe 2ortho substituents of a NCN ‘pincer’ ligand in tungsten chemistry: X-ray structure of [WCl 2(NPh)(C 6H 3{CH 2NMeCH 2}-2-{CH 2NMe 2}-6)

Reaction of the aryl and alkyl metal derivatives, [Li(C 6H 3(CH 2NMe 2) 2-2,6)] 2 ( 1), in situ prepared ‘Zn(C 6H 3(CH 2NMe 2) 2-2,6) 2’ ( 2), [Li(CH 2{C 6H(CH 2NMe 2) 2-2,6-Me 2-3,5})] ( 3) and [Zn(CH 2{C 6H(CH 2NMe 2) 2-2,6-Me 2-3,5}) 2] ( 4), respectively, with either WOCl 4 or [W(NPh)Cl 4(Et 2O)] in Et 2O yielded insoluble products. According to elemental analysis and mass balance the adducts that were formed contained all of the starting compounds, including the respective Li and Zn salts eventually formed. However, when the arylzinc reagent 2 was reacted with [W(NPh)Cl 4(Et 2O)] in CH 2Cl 2, [WCl 2(NPh)(C 6H 3{CH 2N(Me)CH 2}-2-{CH 2NMe 2}-6)] ( 6) was formed, which was isolated in high yield. The single-crystal X-ray determination of 6 showed a NCN ligand that is η 3- mer- N,C,N-bonded to the tungsten(VI) center via the (aryl)C ipso carbon and the two ortho- N-donor atoms. As one of the NCH 3 groups has undergone C–H activation, thus forming an azatungstacyclopropane ring, the NCN-pincer ligand is overall bonded to the tungsten centre as a tetradentate, η 4- N,C,N,C coordinating dianionic ligand. The corresponding tungsten(VI) alkylidene complex [W(CH 2SiMe 3)(NPh)(C 6H 3{CHN(Me)CH 2}-2-(CH 2NMe 2)-6)] ( 7) was generated by reaction of 6 with two equivalents of LiCH 2SiMe 3.

Bisphenolate iron(II) complexes with intramolecularly coordinating nitrogen Lewis bases

The synthesis and characterisation of a novel Fe(II) bisphenolate complex [Fe(OC 6H 4CH 2NMe 2-2) 2] 2 ( 1) from [Na(OC 6H 4CH 2NMe 2-2)] and anhydrous FeCl 2 is reported. The solid state structure has been elucidated by single crystal X-ray analysis and shows a dimeric structure with two bridging and two terminal phenolate ligands. Compound 1 reacts with pyridine to form the adduct [Fe(OC 6H 4CH 2NMe 2-2) 2(py) 2] ( 2). Similarly, 2 equiv. of [Na(OC 6H 2(CH 2NMe 2) 2-2,6-Me-4)] were reacted with FeCl 2 and the thus in situ prepared ‘[Fe(OC 6H 2(CH 2NMe 2) 2-2,6-Me-4) 2] n ’ ( 3) was reacted with pyridine to form the adduct [Fe(OC 6H 2(CH 2NMe 2) 2-2,6-Me-4) 2(pyr) 2] ( 4). Compound 4 was characterised by single crystal X-ray analysis. Attempts to use these compounds as catalysts in the oxidation of cyclohexane with t-butylhydroperoxide (cat.:C 6H 12:t-BuOOH=1:1000:100) resulted in the direct formation of brown coloured products, probably as a result of irreversible oxidation of 1, 2, 3 and 4, respectively. No cyclohexanol or cyclohexanone was formed.

Titanium σ-acetylides as building blocks for heterobimetallic transition metal complexes: synthesis and redox behaviour of π-conjugated organometallic systems

A series of related Ti σ-acetylides of the type {Ti}CCR ({Ti}=(η 5-C 5H 5) 2Ti(CH 2SiMe 3); 2: R=SiMe 3; 3: R=C 6H 3(CH 2NMe 2) 2-3,5; 4: R=C 6H 2I-4-(CH 2NMe 2) 2-3,5; 5: R=C 6H 4CN-4; 6: R=C 5H 4N-4; 7: R=Fc, Fc=(η 5-C 5H 4)Fe(η 5-C 5H 5); 8: R=C 6H 4(CC{Ti})-4) have been prepared by reacting the corresponding lithium acetylides with {Ti}Cl ( 1). The X-ray crystal structure determination of {Ti}CCSiMe 3 ( 2) is reported. This compound exhibits a one-dimensional (1D) arrangement with respect to the Ti–CC unit. The reaction of 2 with [CuCl] n afforded 1 and [CuCCSiMe 3] n ( 10) and is proposed to occur via prior formation of the dimeric intermediate [(η 2-{Ti}CCSiMe 3) 2Cu 2Cl 2]. The chemical oxidation of {Ti}CCFc, 7, with Ag[BF 4] yielded HCCFc and an undefined Ti species. Treatment of 5 or 6 with {Ru}NN{Ru} ({Ru}= mer, trans-[RuCl 2(NN′N)]; NN′N=η 3-C 5H 3N(CH 2NMe 2) 2-2,6) produced intensively coloured heterodinuclear compounds, such as [{Ti}CCC 5H 4N-4]{Ru} ( 16). In contrast, 5 and 6 react with cationic Pt compounds of the type [{Pt}·L][X] ({Pt}=[Pt(C 6H 3{CH 2NMe 2} 2-2,6] +; L=H 2O, MeCN; X=BF 4, OTf) to give product mixtures rather than defined compounds. Electrochemical studies on some of the bimetallic compounds show that the Ti(III)/Ti(IV) redox potential appears to be reversible and is shifted to a more negative value upon substitution of the Cl ligand in 1 by CCR (compounds 2– 8). Whereas the nature of R in {Ti}CCR has an influence on the Ti(III)/Ti(IV) redox potential, the attachment of a second metal onto the π-conjugated system has only negligible effect on the electrochemical properties of the Ti centre.

Intramolecularly Stabilized 1,4-Phenylene-Bridged Homo- and Heterodinuclear Palladium and Platinum Organometallic Complexes Containing N,C,N-Coordination Motifs; η1-SO2 Coordination and Formation of an Organometallic Arenium Ion Complex with Two Pt−C σ-Bonds

The new ligand precursors [1-(Me3Si)-4-(R){C6(CH2NMe2)4-2,3,5,6}] (2, R = Me3Si; 3, R = H) have been used for the preparation of ionic 1,4-phenylene-bridged bispalladium(II) and palladium(II)-platinum(II) complexes [1-{M(MeCN)}-4-{M'(MeCN)}{C6(CH2NMe2)4-2,3,5,6}](BPh4)2 (5b, M = M' = Pd; 10, M = Pd, M' = Pt). Lithium-halogen exchange of the new ligand precursor C6Br2(CH2NMe2)4-2,3,5,6, 11, generates a presumably polymeric organodilithium reagent, 12, which in a transmetalation reaction with [PtCl2(Et2S)2] affords the 1,4-phenylene-bridged bisplatinum complex [1,4-(PtCl)2{C6(CH2NMe2)4-2,3,5,6}], 13. Reaction of colorless 13 with SO2 affords the unique orange bis-SO2 adduct [1,4-{PtCl(1-SO2)}2{C6(CH2NMe2)4-2,3,5,6}], 16, of which an X-ray crystal structure has been determined. The ionic derivative [1,4-{Pt(MeCN)}2{C6(CH2NMe2)4-2,3,5,6}](BPh4)2, 14b, obtained by reaction of 13 with AgOTf in MeCN followed by addition of NaBPh4, has been the subject of an X-ray crystal structure determination. The X-ray molecular structures of 5b, 10, and 14b have been determined and show intramolecular M···M distances of ca. 6.5 A. The bistriflate complex [1,4-{Pt(MeCN)}2{C6(CH2NMe2)4-2,3,5,6}](OTf)2, 14a, has also been used for the synthesis of the organometallic polymer {[1,4-{PtI(-I)}2{C6(CH2N(H)Me2)4-2,3,5,6}]n}(OTf)2n, 24. Triflate complex 14a slowly reacts with iodomethane to afford the dark red air-stable crystalline complex [1,4-{PtI}2{C6Me-1-(CH2NMe2)4-2,3,5,6}](OTf), 23. The X-ray molecular structure of 23 shows it to be a unique arenium ion species with two para-oriented -bonded iodoplatinum substituents.

Kinetic resolution of racemic 2,2′-bis(trifluoromethane-sulfonyloxy)-1,1′-binaphthalene by chiral dimethylaluminum complexes and an achiral Pd catalyst, as well as by achiral dimethylaluminum reagents in the presence of a chiral Pd catalyst

Kinetic resolution of the racemic title compound was shown to take place during its methylation with either (Me 2AlOCH 2CH 2OMe) 2 or Me 2Al(CH 2NMe 2 in the presence of an optically active Pd(binap) catalyst, as well as during its alkylation with either ( S)-(+)-[Me 2AlOCH 2CH(Me)OCH 2Ph] 2 or ( S)-(+)-[Me 2AlOCH 2CH(CH 2CHMe 2)NMe 2] 2 in the presence of an achiral palladium complex. The ee values of the resolved binaphthyl derivatives by the two methods were up to 69 and 12%, respectively. The latter method represents the first application of a stabilized dialkylaluminum complex with a chiral chelating ligand for asymmetric induction.

Organogold(III) metallacyclic chemistry. Part 4 . Synthesis, characterisation, and biological activity of gold(III)-thiosalicylate and -salicylate complexes

The silver(I) oxide mediated reactions of the gold(III) dichloride complex [{C 6H 3(CH 2 NMe 2)-2-(OMe)-5}A uCl 2] 2a with thiosalicylic or salicylic acid gives the respective complexes [{C 6H 3(CH 2 NMe 2)-2-(OMe)-5}A u{XC 6H 4(COO )-2}] 3a (X=S) or 6b (X=O), containing chelating thiosalicylate or salicylate dianion ligands. X-ray studies show that for the thiosalicylate system, the thiosalicylate sulfur atom is trans to the N, N-dimethylamino group, whereas in the structure of the salicylate complex, it is the carboxylate group that is trans to NMe 2. Both complexes show puckered metallacycles in the solid state. Electrospray mass spectrometry (ESMS) shows strong [M+H] + and [2M+H] + ions for both the gold-thiosalicylate and -salicylate complexes, and these ions possess a high stability towards cone voltage-induced fragmentation. ESMS was also used to identify a minor impurity, the bis(cyclo-aurated) cationic complex [A u{C 6H 3(CH 2N Me 2)-2-(OMe)-5}2] + in the starting dihalide complex 2a and in the product 3a. This complex can be formed by reaction of Me 4N[AuCl 4] with 2 equivalents of the organomercury precursor [Hg{C 6H 3(CH 2NMe 2)-2-(OMe)-5}Cl]. The biological (antitumour, antimicrobial and antiviral) activities are also reported, and these reveal the complexes have moderate to high anti-tumour, antibacterial and antifungal activity.