Werner Complexes with ω‐Dimethylaminoalkyl Substituted Ethylenediamine Ligands: Bifunctional Hydrogen‐Bond‐Donor Catalysts for Highly Enantioselective Michael Additions

The racemic carbonate complex [Co(en)₂O₂CO]⁺ Cl^? (en=1,2‐ethylenediamine) and (S)‐[H₃NCH((CH₂)_nNHMe₂)CH₂NH₃]³⁺ 3 Cl^? (n=1–4) react (water, charcoal, 100 °C) to give [Co(en)₂((S)‐H₂NCH((CH₂)_nNHMe₂)CH₂NH₂)]⁴⁺ 4 Cl^? ( 3 a – d H⁴⁺ 4 Cl^?) as a mixture of Λ/Δ diastereomers that separate on chiral‐phase Sephadex columns. These are treated with NaOH/Na⁺ BAr_f^? (BAr_f=B(3,5‐C₆H₃(CF₃)₂)₄) to give lipophilic Λ‐ and Δ‐ 3 a–d ³⁺ 3 BAr_f^?, which are screened as catalysts (10 mol %) for additions of dialkyl malonates to nitroalkenes. Optimal results are obtained with Λ‐ 3 c ³⁺ 3 BAr_f^? (CH₂Cl₂, ?35 °C; 98–82 % yields and 99–93 % ee for six β‐arylnitroethenes). The monofunctional catalysts Λ‐ and Δ‐[Co(en)₃]³⁺ 3 BAr_f^? give enantioselectivities of <10 % ee with equal loadings of Et₃N. The crystal structure of Δ‐ 3 a H⁴⁺ 4 Cl^? provides a starting point for speculation regarding transition‐state assemblies.     

Complex Formation of PdII Ion with the Tripodal Ligand Tris[2-(dimethylamino)ethyl]amine

The complex formation of Pd^II with tris[2-(dimethylamino)ethyl]amine (N(CH₂CH₂N(CH₃)₂)₃, Me₆tren) was investigated at 25° and ionic strength I = 1, using UV/VIS, potentiometric, and NMR measurements. Chloride, bromide, and thiocyanate were used as auxiliary ligands. The stability constant of [Pd(Me₆tren)]²⁺ in various ionic media was obtained: log β([Pd(Me₆tren)] = 30.5 (I = 1(NaCl)) and 30.8 (I = 1(NaBr)), as well as the formation constants of the mixed complexes [Pd(HMe₆tren)X]²⁺ from [Pd(HMe₆tren)(H₂O)]³⁺:log K = 3.50 = Cl^?) and 3.64 (X^? = Br^?) and [Pd(Me₆tren)X]⁺ from [Pd(Me₆tren)(H₂O)]²⁺: log K = 2.6 (X^? = Cl^?), 2.8(Br^?) and 5.57 (SCN^?) at I = 1 (NaClO₃). The above data, as well as the NMR measurements do not provide any evidence for the penta-coordination of Pd^II, proposed in some papers.     

Synthesis and characterization of η<Superscript>3</Superscript>-allyl palladium(II) complexes with Ph<Subscript>2</Subscript>P(S)CHP(S)Ph<Subscript>2</Subscript> and OC(CF<Subscript>3</Subscript>)CHCO(C<Subscript>4</Subscript>H<Subscript>3</Subscript>S) co-ligands

The new complexes [(η³-Me₂CCMeCH₂)Pd{η²-Ph₂P(S)CHP(S)Ph₂] (1), [(η³-Me₂CCMeCH₂)Pd{η²-OC(CF₃) CHCO(C₄H₃S)}] (2) and [(η³-CH₂CMeCH₂)Pd{η²-OC(CF₃)CHCO(C₄H₃S)}] (3) have been synthesized by reacting [(η³-allyl)Pd(μ-Cl)]₂ with Ph₂P(S)CH₂P(S)Ph₂ and OC(CF₃)CH₂CO(C₄H₃S) in the presence of base. All have been characterized by elemental analysis, FT-IR, ¹H-n.m.r and FAB-mass spectroscopy. Spectroscopic studies suggest that both ligands are bidentate, forming six-membered Pd-S-P-C-P-S and Pd-O-C-C-C-O palladacycles, the η³-allyl group completing the coordination sphere.     

High selectivity for l-cysteine residue at axial solvated site of trigonal-bipyramidal palladium(II) complex with tripodal tetradentate phosphine

The five-coordinate trigonal-bipyramidal palladium(II) and platinum(II) complexes with sulfur-coordinated glutathione at the axial position, [Pd(gluta)(pp₃)](BF₄) and [Pt(gluta)(pp₃)](PF₆) (gluta = glutathionate, pp₃ = tris[2-(diphenylphosphino)ethyl]phosphine), were prepared and characterized by ³¹P NMR spectroscopy. The dimeric square-planar platinum(II) complex [Pt(pp₃)]₂(PF₆)₄ gave the monomeric five-coordinate solvated complex, [Pt(pp₃)(CH₃CN)]²⁺, in acetonitrile. Extraction experiments for amino acids from the aqueous solution to the chloroform layer were carried out by using [Pd(pp₃)(CH₃CN)]²⁺, [Pt(pp₃)(CH₃CN)]²⁺, and [Pd(p₃)(CH₃CN)]²⁺ (p₃ = bis[2-(diphenylphosphino)ethyl]phenylphosphine) as extractants. High selectivity for the thiolate sulfur atom in l-cysteinate was observed at the solvated coordination site in [Pd(pp₃)(CH₃CN)]²⁺. The selectivity was applied to extraction of l-cysteinate from a mixture of some amino acids and, further, the reduced form of glutathionate from a mixture of the reduced and oxidized forms of glutathione.     

Novel Copolymers of 4-Fluorostyrene. 6. Dialkoxy Ring-Substituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₃CH?C(CN)₂ (where R is 2,3-(CH₃O)₂, 2,4-(CH₃O)₂, 2,5-(CH₃O)₂, 2,6-(CH₃O)₂, 3,4-(CH₃O)₂, and 3,5-(CH₃O)₂ and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r ₁) for the monomers is 2,6-(CH₃O)₂(2.8) > 2,5-(CH₃O)₂(2.5) > 2,3-(CH₃O)₂ (2.1) > 3,5-(CH₃O)₂ (1.8) > 3,4-(CH₃O)₂ (0.9) > 2,4-(CH₃O)₂ (0.7). High T_g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250–400°C range with residue, which then decomposition in 400–800°C range.     

Kinetics and Mechanism of the Cerium(IV) Oxidation of Arnold's Base and the Protonation and Hydroxylation of Michler's Hydrol Blue

In aqueous H₂SO₄, Ce(IV) ion oxidizes rapidly Arnold's base((p-Me₂NC₆H₄)₂CH₂, Ar₂CH₂) to the protonated species of Michler's hydrol((p-Me₂NC₆H₄)₂CHOH, Ar₂CHOH) and Michler's hydrol blue((p-Me₂NC₆H₄)₂CH⁺, Ar₂CH⁺). With Ar₂CH₂ in excess, the rate law of the Ce(IV)-Ar₂CH₂ reaction in 0.100 M H₂SO₄ is expressed -d[Ce(IV)]/dt = k_app[Ar₂CH₂]₀[Ce(IV)] with k_app = 199 ± 8M^?1s^?1 at25°C. When the consumption of Ce(IV) ion is nearly complete, the characteristic blue color of Ar₂CH⁺ ion starts to appear; later it fades relatively slowly. The electron transfer of this reaction takes place on the nitrogen atom rather than on the methylene carbon atom. The dissociation of the binuclear complex [Ce(III)ArCHAr-Ce(III)] is responsible for the appearance of the Ar₂CH⁺ dye whereas the protonation reaction causes the dye to fade. In highly acidic solution, the rate law of the protonation reaction of Michler's hydrol blue is -d[Ar₂CH⁺]/dt = k_obs[Ar₂CH⁺] where K_obs = ((ac + 1)[H*] + bc[H⁺]²)/(a + b[H⁺]) (in HClO₄) and k_obs= ((ac + 1 + e[HSO₄^?])[H⁺] + bc[H⁺]² + d[HSO₄^?] + q[HSO₄^?]²/[H⁺])/(a + b[H⁺] + f[HSO₄^?] + g[HSO₄^?]/[H⁺]) (in H₂SO₄), and at 25°C and μ = 0.1 M, a = 0.0870 M s, b = 0.655 s, c = 0.202 M^?1s^?1, d = 0.110, e = 0.0070 M^?1, f = 0.156 s, g = 0.156 s, and q = 0.124. In highly basic solution, the rate law of the hydroxylation reaction of Michler's hydrol blue is -d[Ar₂CH⁺]/dt = k_OH[OH^?]₀[Ar₂CH⁺] with k_OH = 174 ± 1 M^?1s^?1 at 25°C and μ = 0.1 M. The protonation reaction of Michler's hydrol blue takes place predominantly via hydrolysis whereas its hydroxylation occurs predominantly via the path of direct OH attack.     

Novel Copolymers of 4-Fluorostyrene. 8. Some Ring-Trisubstituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₂CH=C(CN)₂ (where R is 2,4-(CH₃O)₂-3-CH₃, 2,3,4-(CH₃O)₃, 2,4,5-(CH₃O)₃, 2,4,6-(CH₃O)₃, 3,4,5-(CH₃O)₃, 6-Br-3,4-(CH₃O)₂), 2,3,5-Cl₃, 2,3,6-Cl₃ and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r ₁) for the monomers is 3,4,5-(CH₃O)₃(10.6) > 2,4,6-(CH₃O)₃(9.3) > 2,4,5-(CH₃O)₃ (5.4) > 2,3,4-(CH₃O)₃ (4.4) > 6-Br-3,4-(CH₃O)₂ (3.2) > 2,3,5-Cl₃ (1.5) > 2,3,6-Cl₃ (1.0) > 2,4-(CH₃O)₂-3-CH₃ (0.7). High T _g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–400°C range with residue, which then decomposed in the 400–800°C range.     

Novel Copolymers of Vinyl Acetate with Alkyl and Alkoxy Ring‐Disubstituted 2‐Phenyl‐1,1‐dicyanoethylenes

Electrophilic trisubstituted ethylene monomers, alkyl and alkoxy ring‐disubstituted 2‐phenyl‐1,1‐dicyanoethylenes, RC₆H₃CH?C(CN)₂ (where R is 2,4‐(CH₃)₂, 2,5‐(CH₃)₂, 2,3‐(CH₃O)₂, 2,4‐(CH₃O)₂, 2,5‐(CH₃O)₂, 3,4‐(CH₃O)₂, 3‐C₂H₅O‐4‐CH₃O, 4‐CH₃O‐3‐CH₃), were synthesized by piperidine catalyzed Knoevenagel condensation of ring‐disubstituted benzaldehydes and malononitrile, and characterized by CHN elemental analysis, IR, ¹H‐ and ¹³C‐NMR. Novel copolymers of the ethylenes and vinyl acetate were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C‐NMR, GPC, DSC, and TGA. High T _g of the copolymers, in comparison with that of polyvinyl acetate, indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 190–700°C range.     

Homo‐ and copolymerization of norbornene and 5‐norbornene‐2‐yl acetate with bis‐(β‐ketonaphthylamino)palladium(II)/B(C6F5)3 catalytic system

The polymerization of norbornene with bis(β‐ketonaphthylamino) palladium(II), Pd{CH₃C(O)CHC[N(naphthyl)]CH₃}₂, in combination with tris(pentafluorophenyl)borane (B(C₆F₅)₃), was investigated by varying the B:Pd(II) molar ratio, monomer concentration, reaction temperature, and time. The catalytic activity was found to reach 2.8 × 10⁴ gPolymer/(molPd^?h) and the obtained polynorbornene (PNBE) was confirmed to be vinyl addition polymer and showed good thermo‐stability (T_dec > 350°C), but exhibited poor solubility in organic solvents due to the relative higher stereo regularity. Pd{CH₃C(O)CHC[N(naphthyl)]CH₃}₂/B(C₆F₅)₃ system is also an active catalyst for copolymerization of norbornene and 5‐norbornene‐2‐yl acetate (NBE‐OCOCH₃) in toluene with moderate yields (in 9.2–36.5% yields) and produces the addition‐type copolymer with relatively high molecular weights (0.96 × 10⁴–2.13 × 10⁴ g/mol). The incorporation of functional group in the copolymer can be controlled up to 0.9–23.5 mol% by varying the NBE‐OCOCH₃ monomer feed ratios from 10 to 90%. The copolymers are proved to be noncrystalline and show good solubility in common organic solvents and excellent thermal stability up to 350°C. Copyright © 2011 John Wiley & Sons, Ltd.     

Binary salt of a palladium(II) complex with (phosphonomethyl)phosphonic (medronic) acid comprising `handbell‐like' [Pd{μ‐CH2(PO3)2}]3 units

The asymmetric unit of the title compound, dipotassium bis[hexaaquanickel(II)] tris(μ₂‐methylenediphosphonato)tripalladium(II) hexahydrate, K₂[Ni(H₂O)₆]₂[Pd₃{CH₂(PO₃)₂}₃]·6H₂O, consists of half a {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ anion [one Pd atom (4e) and a methylene C atom (4e) occupy positions on a twofold axis] in a rare `handbell‐like' arrangement, with K⁺ and [Ni(H₂O)₆]²⁺ cations to form the neutral complex, completed by three solvent water molecules. The {[Pd{CH₂(PO₃)₂}]₃}⁶⁻ units exhibit close Pd...Pd separations of 3.0469 (4) Å and are packed via intermolecular C—H...Pd hydrogen bonds. The [KO₉] and [NiO₆] units are assembled into sheets coplanar with (011) and stacked along the [100] direction. Within these sheets there are [K₄Ni₄O₈] and [K₂Ni₂O₄] loops. Successive alternation of the sheets and [Pd{CH₂(PO₃)₂}]₃ units parallel to [001] produces the three‐dimensional packing, which is also supported by a dense network of hydrogen bonds involving the solvent water molecules.     

Synthesis,properties and crystal structures of volatile β-ketoiminate Pd complexes,precursors for palladium chemical vapor deposition

The β-aminovinylketone ligands CH₃C(NH₂)CHC(O)CH₃ (1) and CH₃C(NHCH₃)CHC(O)CH₃ (2) were synthesized from 2,4-pentandione by amination with a water solution of the appropriate amine in toluene at room temperature. The reactions of 1 and 2 with the PdCl₂ salt in amine medium gave the volatile chelate metal complexes Pd[CH₃C(NH)CHC(O)CH₃]₂ (3) and Pd[CH₃C(NCH₃)CHC(O)CH₃]₂ (4). The obtained compounds were identified by elemental analysis, ¹H and ¹³С NMR, IR-spectroscopy and were characterized by TGA and a single-crystal X-ray diffraction study. In compounds 3 and 4, the Pd atom has a square coordination environment Pd O₂N₂.     

Studies in aryltin chemistry: part 7. Spectroscopic and fungicidal studies of some p-substituted tri-aryltin acetates,oxides and hydroxides

The fungicidal activity of a series of aryltin compounds, (p-ZC₆H₄)₃SnX (X=OAc, OH, or 1/2O), where Z=F, Cl, CH₃, CH₃O, C₂H₅ or (CH₃)₃C, and for which IR and NMR (¹¹⁹Sn) data are reported, has been assessed by radial growth assays on Aspergillus niger, Botrytis cinera, Mucor hiemalis, Fusarium solani and Penicillium chrysogenum, and the results compared with those for the Ph₃SnOAc and Ph₃SnOH archetypes. In most cases, para-substitution only slightly reduces biocidal activity, but with p-CH₃O the aryltin is completely ineffective. This result correlates with the seemingly decreased ability of the ‘(p-CH₃OC₆H₄)₃Sn’ moiety to achieve a trigonal-bipyramidal five-coordinate geometry with oxygen atoms in the axial positions, all other Ar₃SnOAc and Ar₃SnOH having this geometry in the solid state. A model for fungicidal action is proposed based on the need for the organotin inhibitor to attain the above geometry in the active site that it occupies in the ATPase enzyme, being the required condition for its biological activity. © 1997 John Wiley & Sons, Ltd.     

Homogeneous Catalysis with Dicationic PdII Complexes: Aldol reaction of methyl isocyanoacetate with benzaldehyde

A series of dicationic Pd^II-acetonitrile complexes containing bi- and tridentate nitrogen and bidentate phosphine ligands (some of which are chiral) has been prepared as their BF₄ salts. The molecular structures for two of these, [Pd(CH₃CN)₂(bipy)] (BF₄)₂ ( 4 ) and [Pd(CH₃CN)((pybox)(i-Pr))] (BF₄)₂((S,S)-pybox(i-Pr) = 2,6-bis[(S)-4′-isopropyloxazolin-2′-yl]pyridine, 5 ) have been determined by X-ray diffraction. All of these complexes are shown to be effective homogeneous catalysts for the aldol-type condensation of the isonitrile, methyl isocyanoacetate, with benzaldehyde. Two isonitrile complexes, [Pd(2,2′-bipyridyl)(CNCH₂COOCH₃)₂] (BF₄)₂ and [Pd((S,S)-pybox(i-Pr))(CNCH₂COOCH₃)] (BF₄)₂, have also been prepared.     

15N-NMR. and 31P-NMR. Studies of palladium and platinum complexes

¹⁵N-NMR. parameters for the complexes trans-[MCl₂ (¹⁵NH₂ (CH₂)₅CH₃)L] are reported; M = Pt, Pd, L = PBu, PMePh₂, P (p-CH₃? C₆H₄)₃, AsBuⁿ₃, AsMePh₂, As (p-CH₃C₆H₄)₃, NH₂ (CH₂)₅CH₃ and (for Pt) C₂H₄. For both metals, the NMR. parameters depend on the trans-influence of the ligand L. The values ¹J (¹⁹⁵Pt, ¹⁵N) vary from 138 to 336 Hz and can be shown to correlate with the values ¹J (¹⁹⁵Pt, ³¹P) in the complexes trans-[PtCl₂ (PBu)L]. There is a linear relation between the ¹⁵N chemical shifts in the complexes of the two metals. The reactions of the complexes sym-trans-[M₂Cl₄L₂], M = Pd, Pt, L = a tertiary phosphine or arsine, with neutral ligands are described. ¹⁹⁵Pt-, ³¹P- and ¹³C-NMR. data are reported.     

Synthesis and Polymerization of the Organometallic Monomer Series Based on Cymantrenylethyl Acrylate

{η⁵ -C₅H₄[CH(CH₃)OC(O)CH = CH₂])Mn(CO)3, {η⁵—C₅[CH-(CH₃)OC(O)C(CH₃)=CH₂]]Mn(CO)₃, and {η⁵—C₅H₄[CH(CH₃)-OC(O)CH=C(CH₃)2])Mn(CO)₃ were synthesized (63, 57, and 51%, respectively) from {η⁵—C₅H₄[CH(CH₃)OH])Mn(CO)₃, toluene-sulfonic acid, and the acrylic, methacrylic, and dimethylacrylic acids, and from (η⁵-C₅H₄[CH(CH₃)OH]}Mn(CO)₃, pyridine, and the acrylic, methacrylic, and dimethylacrylic acyl chlorides [26, 48, and 25% (impure), respectively]. No product was obtained when NaH was used as the base in the latter method. The acrylate and methacrylate monomers were bulk homopolymerized at 65°C with AIBN (75% yield, M_n = 88,550 g/mol; 78% yield, M_n = 349,350 g/mol, respectively). The dimethylacrylate did not polymerize under these conditions. The polymers lost vinylcymantrene upon heating to 257 and 279°C, respectively. The polymers did not exhibit a clear T_g but were observed to soften at 85 and 160°C, respectively, and they could be pulled into fibers.     

Dialkylterphenyl Phosphine-Based Palladium Precatalysts for Efficient Aryl Amination of N-Nucleophiles

A series of 2-aminobiphenyl palladacycles supported by dialkylterphenyl phosphines, PR₂Ar′ (R=Me, Et, iPr, Cyp (cyclopentyl), Ar′=Ar^Dipp2, Ar^Xyl2f, Dipp (2,6-C6H3-(2,6-C6H3-(CHMe2)2)2), Xyl=xylyl) have been prepared and structurally characterized. Neutral palladacycles were obtained with less bulky terphenyl phosphines (i.e., Me and Et substituents) whereas the largest phosphines provided cationic palladacycles in which the phosphines adopted a bidentate hemilabile k¹-P,η¹-C_arene coordination mode. The influence of the ligand structure on the catalytic performance of these Pd precatalysts was evaluated in aryl amination reactions. Cationic complexes bearing the phosphines PiPr₂Ar^Xyl2 and PCyp₂Ar^Xyl2 were the most active of the series. These precatalysts have demonstrated a high versatility and efficiency in the coupling of a variety of nitrogen nucleophiles, including secondary amines, alkyl amines, anilines, and indoles, with electronically deactivated and ortho-substituted aryl chlorides at low catalyst loadings (0.25–0.75 mol % Pd) and without excess ligand.     

Metal catalysed Brooke rearrangement of 3-Halo-1-(trimethylsilyl) propan-2-one (Halo = Cl or Br)

The complexes [IrH(CO)(PPh₃)₃], trans-[IrCI(CO)- (PPh₃)₂], [RhH(PPh₃)₄], [Pd(PPh₃)₄], [Pt(trans-stilbene)(PPh₃)₂] and [Pt(η³-CH₂-COCH₂)-(PPh₃)₂] catalyse the rearrangement of Me₃SiCH₂C(O)CH₂Cl to CH₂?C(OSiMe₃)-CH₂Cl.     

Mass spectra of some (Z)-α-Phenyl-β-(2-thienyl)acrylonitriles

The mass spectra of some (Z)α-(4-R′-phenyl)-β-(2-thienyl-5-R)acrylonitriles (R = H, CH₃, Br; R′ = H, CH₃O, CH₃, Cl, NO₂) at 70 eV are reported. Mass spectra exhibit pronounced molecular ions. The compound's where R = H, and CH₃ are characterized by the occurrence of a strong [M - H]⁺ peak. Moreover, in all the compounds a m/z 177 peak occurs. In the compounds where R = H, [M - HS]* and [M - CHS]* ions are present except the nitroderivatives. Where R = CH₃, [M - HS]⁺ ion occurs.     

Reactivity of diacetylplatinum(II) complexes: oxidative addition of alkyl halides and crystal structures of acetyl platinum(IV) complexes

Diacetylplatinum(II) complexes [Pt(COMe)₂(N^N)] (N^N = bpy, 3a; 4,4′-t-Bu₂-bpy, 3b) were found to undergo oxidative addition reactions with organyl halides. The reaction of 3a with methyl iodide and propargyl bromide led to the formation of the cis addition products (OC-6-34)-[Pt(COMe)₂(R)X(bpy)] (R = Me, X = I, 4a; CH₂C≡CH, X = Br, 4k). Analogous reactions of 3a with ethyl iodide, benzyl bromide, and substituted benzyl bromides, 3-(bromomethyl)pyridine, 2-(bromomethyl)thiophene, allyl bromide, and cyclohex-2-enyl bromide led to exclusive formation of the trans addition products (OC-6-43)-[Pt(COMe)₂(R)X(bpy)] (X = I, R = Et, 4b; X = Br, R = CH₂C₆H₅, 4c; CH₂C₆H₄(o-Br), 4d; CH₂C₆H₄(p-COOH), 4e; CH₂-3-py (3-pyridylmethyl), 4f; CH₂-2-tp (2-thiophenylmethyl), 4g; CH₂CH=CH₂, 4h; c-hex-2-enyl (cyclohex-2-enyl), 4i). All complexes 4 were characterized by microanalysis, ¹H and ¹³C NMR and IR spectroscopy. Additionally, complexes 4a, 4f, and 4g were characterized by single-crystal X-ray diffraction analyses. Reactions of 3a and 3b with o-, m- and p-bis(bromomethyl)benzene, respectively, led to the formation of dinuclear platinum(IV) complexes [{Pt(COMe)₂Br(N^N)}₂-{μ-(CH₂)₂C₆H₄}] (5). These complexes were characterized by microanalysis, IR spectroscopy, and depending on their solubility by ¹H and ¹³C NMR spectroscopy, too. A single-crystal X-ray diffraction analysis of complex [{Pt(COMe)₂Br(bpy)}₂{μ-m-(CH₂)₂C₆H₄}] (5b) confirmed its dinuclear composition. The solid-state structures of 4a, 4f, 4g, and 5b are discussed in terms of C–H···O and O–H···O hydrogen bonds as well as π–π stacking between aromatic rings.     

Novel Copolymers of Styrene. 3. Oxy Ring-disubstituted 2-cyano-3-phenyl-2-propenamides

Novel electrophilic trisubstituted ethylene monomers, oxy ring-disubstituted 2-cyano-3-phenyl-2-propenamides, RC₆H₃CH? C(CN)CONH₂ (where R is 2,3-(CH₃O)₂, 2,4-(CH₃O)₂, 2,5-(CH₃O)₂, 2,6-(CH₃O)₂, 3,4-(CH₃O)₂, 3,5-(CH₃O)₂, 3-CH_3?4-CH₃O, 3-C₂H₅O-4-CH₃O, 3,4-(C₆H₅CH₂O)₂, 2-C₆H₅CH₂O-3-CH₃O, 3-C₆H₅CH₂O-4-CH₃O, 4-C₆H₅CH₂O-3-CH₃O) were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and cyanoacetamide, and characterized by CHN analysis, IR, ¹H- and ¹³C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, AIBN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H- and ¹³C-NMR. High T_g of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 300–500°C range with residue (2–9% wt), which then decomposed in the 500–800°C range.