Crystal Structures Of 1a Research Articles

Microwave-assisted and conventional synthesis and stereogenic properties of monospirocyclotriphosphazene derivatives

The reactions of hexachlorocyclotriphosphazene, N 3P 3Cl 6, with N/O donor type N-alkyl or (aryl)-o-hydroxybenzylamines HO(C 6H 4)CH 2NHR(Ar), [R(Ar) = C(CH 3) 3 ( 1), Ph ( 2)] produce monospirocyclic tetrachlorocyclotriphosphazenes ( 1a and 2a). The geminal substituted cyclotriphosphazenes ( 1b, 1d, 2b and 2d) are obtained from the reactions of 1 equiv. of 1a and 2a with 2 equiv. of pyrrolidine or morpholine in THF, while the fully substituted phosphazenes ( 1c, 1e, 2c and 2e) are formed from the reactions of 1a and 2a with the excess pyrrolidine or morpholine in toluene, between 24 and 48 h. The microwave-assisted reactions of 1a and 2a with excess pyrrolidine or morpholine in toluene afford the fully substituted products with higher yields than those which were obtained by conventional methods. The structural investigations of the compounds have been verified by elemental analyses, ESI-MS, FTIR, 1H, 13C, 31P NMR and HETCOR techniques. The crystal structure of 2a is determined by X-ray crystallography and the phosphazene ring is in the flattened boat form. Compounds 1b, 1d, 2b and 2d in which the spiro aryloxy moiety provides the one centre of chirality exist as racemates and the chirality has been confirmed by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA), ( S)-(+)-2,2,2-trifluoro-1-(9′-anthryl)ethanol.

Anaerobic DNA cleavage activity in red light and photocytotoxicity of (pyridine-2-thiol)cobalt(iii) complexes of phenanthroline bases

Cobalt(iii) complexes [Co(pnt)(B)(2)](NO(3))(2) (1-3) of pyridine-2-thiol (pnt) and phenanthroline bases (B), viz. 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in ) and dipyrido[3,2-a:2',3'-c]phenazine (dppz in 3), have been prepared, characterized and their photo-induced anaerobic DNA cleavage activity studied. The crystal structure of 1a as mixed ClO(4)(-) and PF(6)(-) salt of 1 shows a Co(III)N(5)S coordination geometry in which the pnt and phen showed N,S- and N,N-donor binding modes, respectively. The complexes exhibit Co(iii)/Co(ii) redox couple near -0.3 V (vs. SCE) in 20% DMF-Tris-HCl buffer having 0.1 M TBAP. The complexes show binding propensity to calf thymus DNA giving K(b) values within 2.2 x 10(4)-7.3 x 10(5) M(-1). Thermal melting and viscosity data suggest DNA surface and/or groove binding of the complexes. The complexes show significant anaerobic DNA cleavage activity in red light under argon atmosphere possibly involving sulfide anion radical or thiyl radical species. The DNA cleavage reaction under aerobic medium in red light is found to involve both singlet oxygen and hydroxyl radical pathways. The dppz complex shows non-specific BSA and lysozyme protein cleavage activity in UV-A light of 365 nm via both hydroxyl and singlet oxygen pathways. The dppz complex exhibits photocytotoxicity in HeLa cervical cancer cells giving IC(50) values of 767 nM and 19.38 microM in UV-A light of 365 nm and in the dark, respectively. A significant reduction of the dark toxicity of the dppz base (IC(50) = 8.34 microM in dark) is observed on binding to the cobalt(iii) center.

Efficient synthesis of tetradecafluoro-4-phenylheptan-4-ol by a Cannizzaro-type reaction and application of the alcohol as a bulky Martin ligand variant for a new anti-apicophilic phosphorane

Alcohols 8 bearing two identical perfluoroalkyl groups were prepared by the reaction of the corresponding perfluoroalkyl phenyl ketones 7 with 0.5 equivalents of t-BuOK via Cannizzaro-type disproportionation. Utilizing the new bulky bidentate ligand with two n-C(3)F(7) groups generated from 8c, anti-apicophilic phosphorane 5a and its stable isomer 6a were synthesized. The crystal structures of 5a and 6a were slightly affected by the steric repulsion of heptafluoropropyl groups. Kinetic studies on the isomerization of 5a to 6a showed that the new ligand was effective for decreasing the isomerization rate compared with its C(2)F(5) analog 3a to about half.

Vapochromism in Complexes of Stoichiometry [Au2Ag2R4L2]n

Reaction of [NBu4][Au(C6X5)2] (C6X5 = 3,5-C6Cl2F3, C6Cl5) with AgOClO3 in an Et2O/CH2Cl2 mixture affords [Au2Ag2(C6X5)4(OEt2)2]n [C6X5 = 3,5-C6Cl2F3 (1a), C6Cl5 (1b)]. These compounds react with tetrahydrofuran, acetone, acetonitrile or toluene in solution and in the gas phase (with toluene only in solution) to the new complexes [Au2Ag2(C6X5)4L2]n [L = THF (2a, 2b), (CH3)2CO (3a, 3b), CH3CN (4a, 4b), C7H8 (5a, 5b)]. The crystal structures of 2a and 5a have been determined by X-ray diffraction methods, showing polymeric chains formed by the union of tetranuclear Au2Ag2 units via aurophilic interactions. The thermal stability and the vapochromic behaviour of these complexes have been studied by thermogravimetric analysis (TGA), X-ray powder diffraction and FT-IR spectroscopy

Tetrazole-5-carboxylic Acid Based Salts of Earth Alkali and Transition Metal Cations

The tetrazole-5-carboxylate anion was investigated as ligand for earth alkali metal and transition metal complexes. Therefore, the strontium 4a (*3 H(2)O, *2.75 H(2)O, *2.5 H(2)O), barium 4b (*3 H(2)O), copper 4c (*3.5 H(2)O, *4 H(2)O), manganese 4d (*4 H(2)O, *5 H(2)O), and silver tetrazol-5-carboxylate 4e (*1.56 H(2)O) were synthesized and characterized by vibrational spectroscopy (IR), and the crystal structures of 4a (*2.75 H(2)O, *2.5 H(2)O), 4b*3 H(2)O, 4c*4 H(2)O, and 4d*5 H(2)O were determined using single crystal X-ray diffraction. The thermal stability was investigated by DSC-measurements, and the sensitivity toward impact and friction was determined by BAM-standards. The copper, strontium, and barium tetrazole-5-carboxyate proved to be suitable thermal and physical stable colorants for pyrotechnic compositions. The crystal structure of the tetragonal modification of strontium tetrazole-5-carboxyate possesses channels along the c-axis, leading to a porous material.

Synthesis and characterization of novel five-membered palladacycles

3-(2-Chloroquinolin-3-yl)-1,5-bis(3,4,5-trimethoxy-phenyl)-pentane-2,4-dione derivatives 3a–b were conveniently synthesized in excellent yields (82% each) by tandem Knoevenagel condensation reactions of 2-chloro-3-carbaldehyde-quinoline 1a– b with 3,4,5-trimethoxy acetophenone, followed by a base catalyzed Michael addition, such as DBU (1,8-diazabicyclo[5,4,0]undec-7-ene) with or without solvent. The reactions of 3a–b with Pd(dba) 2 in the presence of PPh 3 (1:2) in degassed acetone provided the dinuclear palladium complexes {Pd( C, N-2-C 9H 4N–CH–[–CH 2CO(3,4,5-(OMe-) 3–C 6H 2-] 2–3-R-6)Cl(PPh 3)} 2 [(R = H ( 4a), R = OMe ( 4b)] in moderate yields (38% and 43%), which in turn reacted with an excess of isonitrile XyNC (Xy = 2,6-Me 2C 6H 3) to give the corresponding palladacycles 5a– b in moderate yields (45% and 43%). The palladacycles 5a– b were also obtained in similar yields (32% and 33%) via a one-pot oxidative addition reaction of 3a-b with isonitrile XyNC:Pd(dba) 2 (4:1). The products were characterized by satisfactory elemental analysis and spectral studies (IR, 1H, and 31P NMR). The crystal structure of 5a was determined by X-ray crystallography diffraction studies.

The synthesis of N-Zn, N-Cu complexes involving 2-amino pyridine and ethylenediamine ligands and application to the Henry reaction

The synthesis and characterization of a series of N-Zn, N-Cu complexes with 2-amino pyridine and ethylenediamine ligands (1a–b and 2a–b) have been described. They were synthesized with a simple, one-pot method, and the crystal structures of 1a, 1b, 2a and 2b were determined by X-ray crystallography. The complexes were also characterized by NMR, IR, and elemental analysis. They were used as the catalysts in an application to the Henry reaction, and high yields were obtained under the optimum conditions.

Organometallic dithiolene complexes of benzenedithiolate analogues with π-coordinating and π-interacting Cp* ligand

Organometallic dithiolene complexes, which were formulated as [Cp *M(dcbdt)] and [Cp *M(dcdmp)] (M = Co, Rh, Ir; Cp * = η 5-pentamethylcyclopentadienyl, dcbdt = 4,5-dicyanobenzene-1,2-dithiolate, dcdmp = 2,3-dicyano-5,6-dimercaptopyrazine) were prepared from a low valent Cp *Co I or high valent Cp *M III species (M III = Co III, Rh III, Ir III). The UV–Vis absorption spectral and electrochemical data of them were obtained. The lowest absorption (HOMO–LUMO) energies of them became redshift in order of the Co > Rh > Ir complexes. The reduction potentials suggested that the central metal modifies their LUMO levels. The molecular and crystal structures of [Cp *Co(dcbdt)] ( 3a), [Cp *Co(dcdmp)] ( 4a) and [Cp *Rh(dcdmp)] ( 4b) were determined by X-ray diffraction studies. The cobalt complexes 3a and 4a were monomeric, formally 16-electron complexes and have two-legged piano-stool geometries. The crystal structure of 3a indicated some plane-to-plane intermolecular interactions such as benzene⋯benzene interaction on the dcbdt ligand and two Cp *⋯benzene π–π stackings. 4a showed plane-to-plane interaction with a pseudo-4-fold-symmetry arrangement between the pyrazine moieties on the dcdmp ligand. The rhodium complex 4b was dimeric in the crystal to form a criss-cross arrangement and had a three-legged piano-stool geometry, but it was monomerized in solution. The dimer of 3b was observed in the oxidation process of the cyclic voltammogram.

Increasing the antibacterial activity of gallium(III) against Pseudomonas aeruginosa upon coordination to pyridine-derived thiosemicarbazones

Reaction of N(4)-phenyl-2-formylpyridine thiosemicarbazone (H2Fo4Ph), N(4)-phenyl-2-acetylpyridine thiosemicarbazone (H2Ac4Ph) and N(4)-phenyl-2-benzoylpyridine thiosemicarbazone (H2Bz4Ph) with gallium nitrate gave [Ga(H2Fo4Ph) 2](NO 3) 3 ( 1), [Ga(2Ac4Ph) 2]NO 3 ( 2) and [Ga(2Bz4Ph) 2]NO 3 ( 3). In all complexes coordination of the thiosemicarbazone via the N py–N–S chelating system occurs. In 1 the thiosemicarbazone acts as a neutral ligand while in 2 and 3 the ligand is anionic. Upon slow diffusion of 2 in DMSO [Ga(2Ac4Ph) 2]NO 3·DMSO ( 2a) was formed. The crystal structure of 2a was determined. Upon coordination the antibacterial activity of both gallium and thiosemicarbazones against Pseudomonas aeruginosa significantly increases.

Triangular tricopper(i) clusters supported by donor-substituted triazacyclohexanes

Triazacyclohexanes (R(3)TAC,1a-i ) with pyridyl or thioether functionalities (R) in the N-substituents react with three equivalents of CuX (X = Cl (2), Br (3) or I (4)) in MeCN to give the triangular tri-copper clusters [R(3)TAC(CuX)(3)] (R = 2-pyridylmethyl (2a, 3a ), 5-(t)butyl-2-pyridyl (3b). 2-(3-phenylpropylthio)ethyl (3c), 2-(2-ethyl-butylthio)ethyl (3d), 2-(4-heptylthio)ethyl (2e, 3e ), 2-(1-heptylthio)ethyl (3f), 2-(2,4,6-trimethyl-benzylthio)ethyl (3g), 2-(o-methyl-benzylthio)ethyl (3h) and 2-(o-fluoro-benzylthio)ethyl (2i, 3i 4i)). The thioether complexes are stable towards air and water. The bromide bridge in the clusters can be replaced by chloride (2c, e, f, i) or iodide (4c, e, f, i ) by the reaction of a dichloromethane solution of the cluster with aqueous NaI or AgCl, respectively. Crystal structures of 2a, 3a, 3b, 2e, 3h and show triangular halide-bridged Cu(3) clusters capped by the triazacyclohexane and stabilised by the coordination of one pyridyl or thioether arm to each copper atom. DFT calculations confirm the NMR assignments and reveal the electronic structure of the copper triangle.

Conversion of novel palladacycles into oxopyrrolo[3,4-b]quinolines

The quinolinylcyclopalladated complexes 3a– b were synthesised in good yields (81% and 77%) by the insertion reaction of the prepared dinuclear palladium complexes [Pd( C,N-2-C 9H 4N-CHO-3-R-6)Cl(PPh 3)] 2 [(R = H ( 2a), R = OMe ( 2b)] with isonitrile XyNC (Xy = 2,6-Me 2C 6H 3). The cyclopalladated complexes 3a– b were also obtained in low yields (39% and 33.5%) via a one pot oxidative addition reaction of quinoline chloride 1a– b with isonitrile XyNC:Pd(dba) 2 (4:1). The reactions of 3a– b with Tl(TfO) (TfO = triflate, CF 3SO 3) in the presence of H 2O or EtOH causes depalladation reactions of the complexes to provide the corresponding organic compounds 4a– b, 5a– b and 6a– b in yields (41%, 27% and 18–19%). The products were characterized by satisfactory elemental analyses and spectral studies (IR, 1H, 13C and 31P NMR). The crystal structures of 2a, 3a and 3b were determined by X-ray diffraction studies.

Ph4P][(C5H6N3O3)M(CO)5] (M = Cr, Mo, W; C5H7N3O3 = 1,3‐Dimethyl‐cyanuric Acid). Organometallic Complexes of the 1,3‐Dimethylcyanurate Ligand

Abstract1,3‐Dimethylcyanuric acid (DMCH) forms on deprotonation and reaction with TlF its thallous salt Tl[DCM] (2) which is converted to the phosphonium salt [PPh4][DCM] (3). On the reaction with M(CO)6, the pentacarbonylmetalate salts [Ph4P][(DMC)M(CO)5], M = Cr (4a), Mo (4b) and W (4c) are obtained. IR and NMR data of 4 reveal the DMC anion (1) to have coordination properties similar to those of pyridine. The crystal structures of 4a and 4c are reported.

Oxidative Dehydrogenation of Tris(o-isopropylphenyl)phosphines by Platinum Complexes

The binuclear cyclometalates [Pt2Cl2{2-CMe2C6H4P(C6H4(2-iPr))2}2] (1a) and [Pt2Cl2{2-CMe2C6H3(4-OMe)P(C6H3(2-iPr)(4-OMe))2}2] (1b) react with CHCl2CHCl2 to give the corresponding mononuclear phosphine-alkene chelates [PtCl2{2-CH2═CMeC6H4P(C6H4(2-iPr))2}] (2a) and [PtCl2{2-CH2═CMeC6H3(4-OMe)P(C6H3(2-iPr)(4-OMe))2}] (2b). The product 2a can also be formed directly from [PtCl2(NCtBu)2] and La in CHCl2CHCl2 or by addition of SO2Cl2 to 1a. Addition of an excess of SO2Cl2 to 1b gave [PtCl2{2-CH2═CMeC6H3(4-OMe)P(C6H2(2-iPr)(4-OMe)(5-Cl))2}] (3b), a derivative of 2b featuring meta-chlorine substituents on the terminal P groups as a result of electrophilic aromatic substitution. A mechanism for the conversion of 1a,b to 2a,b is proposed involving an electrophilic alkyl C−H activation by a coordinatively unsaturated platinum(IV) species. The mechanism is supported by the isolation of the diplatinum(IV) cyclometalate [Pt2Cl2{2-CH2C6H3(4-OMe)P(C6H3(2-Me)(4-OMe))2}] as a mixture of syn and anti isomers 5b and 5b′. The crystal structures of 2a and 3b have been determined.

Structural studies on zinc(II) complexes with 2-benzoylpyridine-derived hydrazones

2-Benzoylpyridine-phenylhydrazone (H2BzPh), 2-benzoylpyridine- para-chloro-phenylhydrazone (H2BzpClPh), and 2-benzoylpyridine- para-nitro-phenyl (H2BzpNO 2Ph) hydrazone were obtained and fully characterized, as well as their zinc(II) complexes [Zn(H2BzPh)Cl 2] ( 1), [Zn(H2BzClPh)Cl 2] ( 2) and [Zn(H2BzpNO 2Ph)Cl 2] ( 3). During the syntheses of complex 1 a second product crystallized, which was characterized as [Zn(2BzPh) 2] ( 1a). Upon re-crystallization in 1:9 DMSO:acetone conversion of 2 into [Zn(H2BzpClPh)Cl 2] · H 2O ( 2a) and of 3 into [Zn(2BzpNO 2Ph)Cl(DMSO)] ( 3a) occurred. The crystal structures of 1a, 2a and 3a were determined. In 1a the two nearly perpendicular H2BzPh ligands give rise to a distorted octahedral environment around the metal. The 5-fold coordination around the metal is completed with two chloride ions in 2a and with one chloride and one oxygen atom from DMSO in 3a.

Preparation, Characterization, and Catalytic Studies of Magnesium Phenoxides: Highly Active Initiators for Ring-Opening Polymerization of l-Lactide

A series of sterically bulky phenols (1a−f; EDBP-RTs-H = 2,4-di-tert-butyl-6-(1-(3,5-di-tert-butyl-2-hydroxyphenyl)ethyl)phenyl benzenesulfonate) were synthesized. Their related n-butylmagnesium complexes [(μ-EDBP-RTs)MgnBu]2 (2a−f) and magnesium alkoxides [(EDBP-RTs)Mg(μ-OBn)]2 (3a−f) were prepared and structurally characterized. In the presence of THF, coordination of [(EDBP-RTs)Mg(μ-OBn)]2 (3e) with THF gave the pentacoordinated magnesium complex [(EDBP-RTs)Mg(μ-OBn)(THF)]2 (4). Crystal structures of 2a−c,e, 3a−c,f, and 4 have been determined. Experimental results show that magnesium alkoxides (3a−f) are very reactive initiators toward ROP of l-lactide, with a quantitative yield of polymer (1000 equiv) in less than 4 min.

Synthesis, structure, and electrochemistry of pyridinecarboxamide cobalt(III) complexes; the effect of bridge substituents on the redox properties

Two series of complexes of the types trans-[Co III(Mebpb)(amine) 2]ClO 4 {Mebpb 2− = N, N-bis(pyridine-2-carboxamido)-4-methylbenzene dianion, and amine = pyrrolidine (prldn) ( 1a), piperidine (pprdn) ( 2a), morpholine (mrpln) ( 3a), benzylamine (bzlan) ( 4a)}, and trans-[Co III(cbpb)(amine) 2]X {cbpb 2− = N, N-bis(pyridine-2-carboxamido)-4-chlorobenzene dianion, and amine = pyrrolidine (prldn), X = PF 6 ( 1b), piperidine (pprdn), X = PF 6 ( 2b), morpholine (mrpln), X = ClO 4 ( 3b), benzylamine (bzlan), X = PF 6 ( 4b)} have been synthesized and characterized by elemental analyses, IR, UV–Vis, and 1H NMR spectroscopy. The crystal structure of 1a has been determined by X-ray diffraction. The electrochemical behavior of these complexes, with the goal of evaluating the effect of axial ligation and equatorial substitution on the redox properties, is also reported. The reduction potential of Co III, ranging from −0.53 V for ( 1a) to −0.31 V for ( 3a) and from −0.48 V for ( 1b) to −0.22 V for ( 3b) show a relatively good correlation with the σ-donor ability of the axial ligands. The methyl and chloro substituents of the equatorial ligand have a considerable effect on the redox potentials of the central cobalt ion and the ligand-centered redox processes.

Bidentates versus Monodentates in Asymmetric Hydrogenation Catalysis: Synergic Effects on Rate and Allosteric Effects on Enantioselectivity

C 1-Symmetric phosphino/phosphonite ligands are prepared by the reactions of Ph 2P(CH 2) 2P(NMe 2) 2 with ( S)-1,1'-bi-2-naphthol (to give L A ) or ( S)-10,10'-bi-9-phenanthrol (to give L B ). Racemic 10,10'-bi-9-phenanthrol is synthesized in three steps from phenanthrene in 44% overall yield. The complexes [PdCl 2( L A,B )] ( 1a, b), [PtCl 2( L A,B )] ( 2a, b), [Rh(cod)( L A,B )]BF 4 ( 3a, b) and [Rh( L A,B ) 2]BF 4 ( 4a, b) are reported and the crystal structure of 1a has been determined. A (31)P NMR study shows that M, a 1:1 mixture of the monodentates, PMePh 2 and methyl monophosphonite L 1a (based on ( S)-1,1 '-bi-2-naphthol), reacts with 1 equiv of [Rh(cod) 2]BF 4 to give the heteroligand complex [Rh(cod)(PMePh 2)( L 1a )]BF 4 ( 5) and homoligand complexes [Rh(cod)(PMePh 2) 2]BF 4 ( 6) and [Rh(cod)( L 1a ) 2]BF 4 ( 7) in the ratio 2:1:1. The same mixture of 5- 7 is obtained upon mixing the isolated homoligand complexes 6 and 7 although the equilibrium is only established rapidly in the presence of an excess of PMePh 2. The predominant species 5 is a monodentate ligand complex analogue of the chelate 3a. When the mixture of 5- 7 is exposed to 5 atm H 2 for 1 h (the conditions used for catalyst preactivation in the asymmetric hydrogenation studies), the products are identified as the solvento species [Rh(PMePh 2)( L 1a )(S) 2]BF 4 ( 5'), [Rh(S) 2(PMePh 2) 2]BF 4 ( 6') and [Rh(S) 2( L 1a ) 2]BF 4 ( 7') and are formed in the same 2:1:1 ratio. The reaction of M with 0.5 equiv of [Rh(cod) 2]BF 4 gives exclusively the heteroligand complex cis-[Rh(PMePh 2) 2( L 1a ) 2]BF 4 ( 8), an analogue of 4a. The asymmetric hydrogenation of dehydroamino acid derivatives catalyzed by 3a, b is reported, and the enantioselectivities are compared with those obtained with (a) chelate catalysts derived from analogous diphosphonite ligands L 2a and L 2b , (b) catalysts based on methyl monophosphonites L 1a and L 1b , and (c) catalysts derived from mixture M. For the cinnamate and acrylate substrates studied, the catalysts derived from the phosphino/phosphonite bidentates L A,B generally give superior enantioselectivities to the analogous diphosphonites L 2a and L 2b ; these results are rationalized in terms of delta/lambda-chelate conformations and allosteric effects of the substrates. The rate of hydrogenation of acrylate substrate A with heterochelate 3a is significantly faster than with the homochelate analogues [Rh( L 2a )(cod)]BF 4 and [Rh(dppe)(cod)]BF 4. A synergic effect on the rate is also observed with the monodentate analogues: the rate of hydrogenation with the mixture containing predominantly heteroligand complex 5 is faster than with the monophosphine complex 6 or monophosphonite complex 7. Thus the hydrogenation catalysis carried out with M and [Rh(cod) 2]BF 4 is controlled by the dominant and most efficient heteroligand complex 5. In this study, the heterodiphos chelate 3a is shown to be more efficient and gives the opposite sense of optical induction to the heteromonophos analogue 5.

Synthesis and Biological Activity of Novel Phosphonate Derivatives Containing of Pyridyl and 1,2,3-Triazole Rings

In order to search for novel agrochemicals with high activity and low toxicity, a series of phosphonate derivatives containing 1,2,3-triazolyl and pyridyl rings were synthesized using 2-chloro-5-(chloromethyl)-pyridine as the starting material. IR, 1 H NMR, 31P NMR, MS, and elemental analyses confirmed their structures. The crystal structure of 5a was determined by single crystal X-ray diffraction. Preliminary bioassays indicated that some of them possess good herbicidal and moderate fungicidal activities.

Synthesis and X‐ray Structures of the Polycyclic Dimers {[PhB(μ‐NtBu)2AsN(tBu)H]LiI}2 and [PhB(μ‐NtBu)2AsN(tBu)Li]2

AbstractThe metathesis of [PhB(μ‐NtBu)2]AsCl and tBuN(H)Li in 1:1 molar ratio in diethyl ether produced the amido derivative [PhB(μ‐NtBu)2AsN(tBu)H] (1) in good yield. The lithiation of 1 with one equivalent of nBuLi afforded the lithium salt [PhB(μ‐NtBu)2AsN(tBu)Li] (2a). Both 1 and 2a were characterized by multinuclear NMR spectroscopy. The crystal structure of 2a is comprised of a U‐shaped, centrosymmetric dimer in which the monomeric [PhB(μ‐NtBu)2AsN(tBu)]−Li+ units are linked by Li‐N interactions to give a six‐rung ladder. Oxidation of 2a with one‐half equivalent of I2 in diethyl ether resulted in hydrogen abstraction from the solvent to give the dimeric lithium iodide adduct {[PhB(μ‐NtBu)2AsN(tBu)H]LiI}2 (1·LiI) with a central Li2I2 ring.

Synthesis of Bis(2,6-dinitroaryl)palladium(II) and Mono(2,6-dinitroaryl)platinum(II) Complexes. A New Example of the Transphobia Effect and of Transmetalation from Pt to Hg

The reaction of [Pd(κ2-Ar)(O,O-acac)] (κ2-Ar = κ2-C,O-C6(NO2)2-2,6-(OMe); 1) with 1 equiv of RNC gives [Pd(κ2-Ar)(O,O-acac)(CNR)] [R = Xy (2a), tBu (2b)] and with 4 equiv of XyNC, trans-[Pd(κ1-Ar)2(CNXy)2] (κ1-Ar = κ1-C-C6(NO2)2-2,6-(OMe); 3). This complex has also been obtained (1) by reacting Tl(acac) with 1 equiv of trans-[Pd(κ1-Ar)Cl(CNXy)2] (4), obtained in turn by reacting trans-(NMe4)2[Pd(κ1-Ar)Cl(µ-Cl)]2 (5) with 4 equiv of XyNC or (2) by reacting [Pd(κ1-Ar)(C-acac)(phen)] (6) with 4 equiv of XyNC. cis-[Pt(κ2-Ar)(κ1-Ar)(PPh3)] (7) reacts (1) with Hg(OAc)2 (1:1) to afford a mixture of [Hg(Ar)(OAc)], cis-[{Pt(κ1-Ar)(PPh3)}2(µ-OH)(µ-OAc)] (8), and trans-[{Pt(κ1-Ar)(PPh3)}2(µ-OH)2] (9) or (2) with HgCl2 (1:1) to give trans-[{Pt(κ1-Ar)(PPh3)}2(µ-Cl)2] (10), which reacts with an excess of Ag(OAc) to give 8. The reaction of 10 with excess of KOH, or with Tl(acac) (1:1) gives 9. Reaction of palladium complex 5 with 2 equiv of Hg(OAc)2 affords trans-[Pd(κ2-Ar)(µ-OAc)]2 (11). The crystal structures of 2a, 2...