Synthesis of Differently Substituted N- and P-Aminodiphosphinoamine PNPN-H Ligands

Abstract

On the basis of the known aminodiphosphinoamine ligand Ph₂PN(i-Pr)P(Ph) N(i-Pr)-H (3a), differently substituted aminodiphosphinoamine PNPN-H ligands (3) were prepared. By using different synthetic methods, the N-substituted ligands Ph₂PN (i-Pr)P(Ph)N(c-Hex)-H (3b), Ph₂PN(c-Hex)P(Ph)N(i-Pr)-H (3g), and Ph₂PN(i-Pr)P(Ph) N[(CH₂)₃Si(OEt)₃]-H (3c), in addition to the formerly described Ph₂PN(n-Hex)P (Ph)N (i-Pr)-H (3h), Ph₂PN(i-Pr)P(Ph)N(Et)-H (3d), Ph₂PN(i-Pr)P(Ph)N(Me)-H (3e), and Ph₂PN(c-Hex)P(Ph)N(c-Hex)-H (3f), were obtained. In addition, Ph₂PN(i-Pr)P(Me)N(i-Pr)-H (3i), (cyclopentyl)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3j), (-O-CH₂-CH₂-O-)PN(i-Pr)P(Ph)N(i-Pr)-H (3k), and (1-Ad)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3l) were prepared with different P-substitutions. All compounds were characterized and the molecular structures of the intermediates Ph₂PN(i-Pr)P(Ph)Cl (1a) and (cyclopentyl)₂PN(i-Pr)P(Ph)Cl (1e) and the ligand (1-Ad)₂PN(i-Pr)P(Ph)N(i-Pr)-H (3l) were investigated by single-crystal X-ray diffraction.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

A Flexible Ligand for Multipurpose Complexation

Abstract

The synthesis of the flexible ligand 2,6-bis-{(bis-(2-aminoethyl)amino(methyl}anisole (L) is reported. The basicity behaviour in aqueous solution was studied by potentiometry (25°C, I = 0.15 mol dm^?3, Me₄NCl). L behaves as pentaprotic base (logK₁ = 10.31(2), logK₂ = 9.65(2), logK₃ = 9.16(2), logK₄ = 8.39(2), logK₅ = 2.14(2)). The stability constants for Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes were determined by potentiometry and all of these metalions were found to form both mono and binuclear species: logK_ML = 9.39(3) for Co(II); 14.5(1) for Ni(II); 17.57(7) for Cu(II); 10.62(2) for Zn(II) and 9.83(3) for Cd(II). LogK_M2L = 15.19(3) for Co(II); 19.57(5) for Ni(II); 28.44(3) for Cu(II); 16.77(6) for Zn(II) and 14.62(3) for Cd(II). The crystals of [Cu₄L₂(N₃)₆](ClO₄)₂·H₂O are triclinic, space group P-1 a = 13.770(6), b = 14.043(2), c = 16.800(3) Å, α = 105.700(1), β = 102.790(3), γ = 103.660(3)°, Z = 2. L behaves as ditopic ligand and the crystal lattice consists of branched chains of Cu(II) ions.     

Syntheses and structures of highly hindered N-functionalised alkyl and amido group 12 complexes MR2 (M=Zn, Cd, and Hg), [MRCl]2 (M=Zn and Hg)

The reaction of MCl₂ (M=Zn, Cd and Hg) with Li(2-(C(SiMe₃)₂)(6-Me-C₅H₃N)), [Li(MeR)], affords mononuclear metal(II) alkyls. These, in the solid state, show intramolecular M-N interactions in their four-membered chelate rings, which progressively weaken down the series, the C-M-C angles becoming more open (〈M-N〉= 2.30(2), 2.52(2), 2.913(4) Å, C-M-C=160.7(2), 168.5(2), 180(-)°). Alkylmercury chloride complexes have been prepared by the reaction of HgCl₂ with [Li(MeR)], Li(2-(C(SiMe₃)₂)(C₅H₄N)), [Li(HR)], or Li(2-(NSiMe₃)(6-Me-C₅H₃N)), [Li(mpsa)], or from the redistribution reaction of the dialkyl (or amido) mercury complex with HgCl₂. The alkylmercury chloride complexes are dimeric or polymeric in nature with near-linear 2-coordination; (Hg-Cl=2.329(5), 2.318(4), 2.272(8) Å, Cl-Hg-C(N)=175.0(4), 174.7(4), 175.6(5)°). Cd(2-(CH(SiMe₃))(6-Me-C₅H₃N))₂(tmen), prepared from the reaction of Li(2-(CH(SiMe₃))(6-Me-C₅H₃N)) and CdCl₂ in the presence of tmen, has also been structurally authenticated as the rac isomer with the ipso protons directed towards the tmen.     

Pheromones of insects and their analogs

Dodec-8Z-en-1-ol (VIII) and tetradec-8Z-en-1-ol (IX) and the corresponding acetates (X and IX) — components of the sex pheromones of many species of Lepidoptera — have been synthesized from cyclooctene (I) in three stages. The ozonolysis of (I) (–70°C, CH₂Cl₂-MeOH, NaHCO₃; –20°C, Ac₂O/Et₃N) led to methyl 8-oxooctanoate (II). The DNPH of (II), (III), mp 59–61°C. The coupling of (II) with n-C₃H₁₇ CH=PPh₃ (IV) or with n-C₅H₁₁ CH=PPh₃ (V) (–70°C, 2 h; 25°C, 15 h, Ar) gave the methyl esters of dodec-8Z-enoic (VI) and tetradec-8Z-enoic (VII) acids, respectively. The reduction of (VI) and (VII) [(i-Bu)₂AlH, 0°C, 2 h; 25°C, 15 h] gave the corresponding alcohols (VIII) and (IX) by the acetylation (Ac₂O-Py, 25°C, 24 h) of which, (X) and (XI), were obtained. The yields (%): (II) 80, (VI) 45, (VII) 60, (VIII) 95, (IX) 90, (X) 75, (XI) 74. The IR and PMR spectra of compounds (II) and (VI–XI) are given.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 276–279, March–April, 1989.     

Das Carotinoidspektrum der Hagebutten von Rosa pomifera: Nachweis von (5Z)-Neurosporin; Synthese von (3R, 15Z)-Rubixanthin

Carotenoids from Hips of Rosa pomifera: Discovery of (5Z)-Neurosporene; Synthesis of (3R, 15Z)-Rubixanthin Extensive chromatographic separations of the mixture of carotenoids from ripe hips of R. pomifera have led to the identification of 43 individual compounds, namely (Scheme 2): (15 Z)-phytoene (1) , (15 Z)-phytofluene (2) , all-(E)-phytofluene (2a) , ξ-carotene (3) , two mono-(Z)-ξ-carotenes ( 3a and 3b ), (6 R)-?, ψ-carotene (4) , a mono-(Z)-?, ψ-carotene (4a) , β, ψ-carotene (5) , a mono-(Z)-β, ψ-carotene (5a) , neurosporene (6) , (5 Z)-neurosporene (6a) , a mono-(Z)-neurosporene (6b) , lycopene (7) , five (Z)-lycopenes (7a–7e) , β, β-carotene (8) , two mono-(Z)-β, β-carotenes (probably (9 Z)-β, β-carotene (8a) and (13 Z)-β, β-carotene (8b) ), β-cryptoxanthin (9) , three (Z)-β-cryptoxanthins (9a–9c) , rubixanthin (10) , (5′ Z)-rubixanthin (=gazaniaxanthin; 10a ), (9′ Z)-rubixanthin (10b) , (13′ Z)- and (13 Z)-rubixanthin (10c and 10d , resp.), (5′ Z, 13′ Z)- or (5′ Z, 13 Z)-rubixanthin (10e) , lutein (11) , zeaxanthin (12) , (13 Z)-zeaxanthin (12b) , a mono-(Z)-zeaxanthin (probably (9 Z)-zeaxanthin (12a) ), (8 R)-mutatoxanthin (13) , (8 S)-mutatoxanthin (14) , neoxanthin (15) , (8′ R)-neochrome (16) , (8′ S)-neochrome (17) , a tetrahydroxycarotenoid (18?) , a tetrahydroxy-epoxy-carotenoid (19?) , and a trihydroxycarotenoid of unknown structure. Rubixanthin (10) and (5′ Z)-rubixanthin (10a) can easily be distinguished by HPLC. separation and CD. spectra at low temperature. The synthesis of (3 R, 15 Z)-rubixanthin (29) is described. The isolation of (5 Z)-neurosporene (6a) supports the hypothesis that the ?-end group arises by enzymatic cyclization of precursors having a (5 Z)- or (5′ Z)-configuration.     

一种吡嗪铱(Ⅲ)配合物的晶体结构及光物理性质

合成了一种铱配合物二(4,4'-二氟-5-甲基-2,3-二苯基吡嗪) (乙酰丙酮)合铱[(MDPPF)₂Ir(acac)]的有机电致发光器件(OLED),利用X射线单晶衍射仪测定了该化合物的晶体结构. 利用紫外-可见吸收光谱、发射光谱对其光物理性质进行研究. 结果表明: (MDPPF)₂Ir(acac)的单晶结构属于三斜晶系, P1空间群,晶胞参数a=1.13984(3) nm, b=1.26718(3) nm, c=1.29541(3) nm, α=93.7181(19)°, β=101.638(2)°, γ=110.853(3)°, V=1.69336(7) nm³; (MDPPF)₂Ir(acac)在二氯甲烷溶液中的发射峰为555 nm. 以(MDPPF)₂Ir(acac)为客体材料,制备了结构为ITO/NPB(40 nm)/CBP: (MDPPF)₂Ir(acac)(20 nm)/TPBi(10 nm)/Alq₃ (30 nm)/LiF(1 nm)/Al(100 nm)的一系列不同掺杂浓度器件, 器件的发射峰位于558 nm, 最大亮度达到32700 cd·m^-2,最大电流效率44.3 cd·A^-1, 最大功率效率20.7 lm·W^-1.     

Polarographische und oszillopolarographische Untersuchungen in Trimethylphosphat

Zusammenfassung Das polarographische und oszillopolarographische Verhalten der Perchlorate von Tl(I), Rb(I), K(I), Na(I), Ba(II), Zn(II), Cd(II), Mn(II), Co(II), Ni(II) sowie von Bisbiphenylchrom(I) jodid wurde in wasserfr. Trimethylphosphat (0,1M-Tetraäthylammoniumperchlorat) untersucht. Die Halbwellenpotentiale bei 25° gegen die gesättigte wäßr. Kalomelelektrode werden auf die Bisbiphenylchrom(I)jodid-Skala bezogen.Die Beziehung zwischen Donorzahl des Lösungsmittels undE _1/2 ist erfüllt. Eine Ausnahme, welche auf Chelatbildung zurückzuführen sein dürfte, bilden die in Trimethylphosphat gemessenen Werte für Mn(II), Co(II) und Ni(II).

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Polarographic and oscillopolarographic investigations in trimthhyl phosphate

Polarographic and oscillopolarographic investigations have been carried out on the perchlorates of Tl(I), Rb(I), K(I), Na(I), Ba(II), Zn(II), Cd(II), Mn(II), Co(II), Ni(II) and of bisbiphenylchromium(I)iodide in anhydrous trimethylphosphate (0,1M tetraethylammoniumperchlorate). The half-wave potentials at 25° vs. the aqueous saturated calomel electrode are referred to the bisbiphenylchromium(I)iodide-scale. The relationship between donor number of the solvent andE _1/2 is observed. An exception is given for Mn(II), Co(II) and Ni(II) in trimethylphosphate, which is regarded as due to chelate formation.

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Mit 5 Abbildungen     

Sulfonylcalix[4]arenetetrasulfonate as pre-column chelating reagent for selective determination of aluminum(III), iron(III), and titanium(IV) by ion-pair reversed-phase high-performance liquid chromatography with spectrophotometric detection

Sulfonylcalix[4]arenetetrasulfonate (SO₂CAS) has been examined as a pre-column chelating reagent for ultratrace determination of metal ions by ion-pair reversed-phase high-performance liquid chromatography with spectrophotometric detection. Metal ions were converted into the SO₂CAS chelates in an acetic buffer solution (pH 4.7). The chelates were injected onto a n-octadecylsilanized silica-type Chromolith™ Performance RP-18e column and were eluted using a methanol (50 wt.%)-water eluent (pH 5.6) containing tetra-n-butylammonium bromide (7.0 mmol kg⁻¹), acetate buffer (5.0 mmol kg⁻¹), and disodium ethylendiamine-N,N,N′,N′-tetraacetate (0.10 mmol kg⁻¹). Under the conditions used, Al(III), Fe(III), and Ti(IV) were selectively detected among 21 kinds of metal ions [Al(III), Ba(II), Be(II), Ca(II), Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ga(III), Hf(IV), In(III), Mg(II), Mn(II), Mo(VI), Ni(II), Pb(II), Ti(IV), V(V), Zn(II), and Zr(IV)]. The detection limits on a 3σ blank basis were 8.8 nmol dm⁻³ (0.24 ng cm⁻³) for Al(III), 7.6 nmol dm⁻³ (0.42 ng cm⁻³) for Fe(III), and 17 nmol dm⁻³ (0.80 ng cm⁻³) for Ti(IV). The practical applicability of the proposed method was checked using river and tap water samples.     

Number of species in complexation equilibria of o-, m- and p-CAPAZOXS with Cd, Co, Ni, Pb and Zn ions by PCA of UV-vis spectra

A critical comparison of the selected derivative principal component analysis (PCA) methods on the absorbance matrix data concerning the complexation equilibria between o-CAPAZOXS and Cd²⁺, Pb²⁺ and Zn²⁺ or m-CAPAZOXS and Cd²⁺, Co²⁺, Ni²⁺ and Zn²⁺ or p-CAPAZOXS and Cd²⁺ and Zn²⁺ at 25 °C is provided. As the number of complex species in a complex-forming equilibria mixture is an important step in spectral data treatment, the nine selected index functions for the prediction of the number of light-absorbing species that contribute to a set of spectra is critically tested by the PCA. An improved identification with the second SD(AE) or third derivative TD(AE) and derivative ratio function ROD(AE) for the average error criterion AE is preferred. After the number of various complexes formed the stability constants of species ML, ML₂ (and ML₃, respectively) type log β₁₁, log β₁₂ (and log β₁₃, respectively) for the system of o-CAPAZOXS (ligand L) with the metals (the standard deviation s(log β_pq) of the last valid digits is given in brackets) Cd²⁺ (6.39(5) and 11.51(9)), Pb²⁺ (4.24(2) and 9.01(2)) and Zn²⁺ (5.18(7) and 9.06(10)) and for the system of m-CAPAZOXS with Cd²⁺ (6.59(20) and 11.51(32)), Co²⁺ (7.19(6) and 12.19(8)), Ni²⁺ (7.64(7) and 13.39(12)) and Zn²⁺ (4.83(3) and 9.57(3)) and for the system of p-CAPAZOXS with Cd²⁺ (6.44(5), 10.99(10) and 14.57(25)) and Zn²⁺ (6.84(16), 13.05(29) and 18.74(43)) at 25 °C are estimated using SQUAD(84) nonlinear regression of the mole-ratio spectrophotometric data. The computational strategy is presented with goodness-of-fit tests and various regression diagnostics capable of proving the reliability of the chemical model proposed.     

Asymmetric synthesis and retroracemisation of amino acids via copper(II) complexes with schiff bases between chiral 1-(N,N-dimethylaminomethyl)-2-formylcymantrene and dipeptides

1-(N,N-Dimethylaminomethyl)-2-formylcymantrene (AFCMT) has been resolved into enantiomers through an intermediate formation of diastereomeric complexes with (S)-Ala-(S)-Ala, (S)-Ala-Gly and Gly-(S)-Ala. By the X-ray anomalous dispersion method the absolute configuration of its enantiomers has been determined: (-)₄₃₆ AFCMT-(S), (+)₄₃₆ AFCMT-(R).Alkylation of enantiomeric complexes (R)-and (S)-AFCMT-(GlyGly) Cu(II) with acetaldehyde gives, respectively, (R)-and (S)-Thr with an asymmetric yield of 92–98% and (R)- and (S)-allo-Thr with an asymmetric yield of 95–100%, only the N-terminal glycine being alkylated.The AFCMT enantiomers were also employed for retroracemisation of (R,S)-Ala-(R,S)-Nva; in this case an excess of (S)-Ala and (R)-Nva is obtained for (S)-AFCMT. (R)- and (S)-AFCMT are not liable to racemisation in the course of the threonine synthesis and retroracemisation of depeptides and can be repeatedly employed for these transformations.     

ABA triblock copolymers with pendant hydroxyl groups prepared by controlled cationic polymerization and their use as delivery carrier for paclitaxel

To improve the hydrophilicity of poly(styrene-b-isobutylene-b-styrene) (SIBS), this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers (TPEs) with polyisobutylene (PIB) as rubbery segments. The precursor poly{(styrene-co-4-[2-(tert-butyldimethylsiloxy) ethyl]styrene)-b-isobutylene-b-(styrene-co-4-[2-(tert-butyldimethylsiloxy)ethyl]styrene)}(P(St-co-TBDMES)-PIB-P(St-co-TBDMES)) triblock copolymer was first synthesized by living sequential cationic copolymerization of isobutylene (IB) with styrene (St) and 4-[2-(tert-butyldimethylsiloxy) ethyl]styrene (TBDMES) using 1,4-di(2-chloro-2-propyl)benzene (DiCumCl)/titanium tetrachloride (TiCl₄)/2,6-di-tert-butylpyridine (DtBP) as the initiating system. Then, P(St-co-TBDMES)-PIB-P(St-co-TBDMES) was hydrolyzed in the presence of tetra-butylammonium fluoride to yield poly{[styrene-co-4-(2-hydroxyethyl)styrene]-bisobutylene-b-[styrene-co-4-(2-hydroxyethyl)styrene]} (P(St-co-HOES)-PIB-P(St-co-HOES)) with pendant hydroxyl groups. P(St-co-HOES)-PIB-P(St-co-HOES) used as the paclitaxel carrier was also investigated in this study. Comparing with SIBS, P(St-co-HOES)-PIB-P(St-co-HOES) has exhibited better compatibility with paclitaxel and higher release rate.     

3,6-Di-tert-butyl-o-benzosemiquinone complexes of copper(1) with bidentate bis(diphenylphosphine) ligands. Synthesis, structures, and properties

New mononuclear 3,6-di-tert-butyl-o-benzosemiquinone complexes of copper(1) with bis(diphenylphosphine) ligands were synthesized: (DBSQ)Cu(dppe) (1) (DBSQ=3,6-di-tert-butyl-o-benzosemiquinone and dppe=1,2-bis(diphenylphosphino)ethane), (DBSQ)Cu(dppp) (2) (dppp=1,3-bis(diphenylphosphino)propane), (DBSQ)Cu(dppn) (3) (dppn=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl), and (DBSQ)Cu(dppfc) (4) (dppfc=1,1′-bis(diphenylphosphino)ferrocene). The compositions and structures of complexes1–4 were characterized by elemental analysis and electronic absorption, IR, and ESR spectroscopy. The molecular structures of complexes3 and4 were established by X-ray diffraction analysis. The reactions of elimination and replacement of neutral ligands in the coordination sphere of the complexes were studied by ESR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2333–2340, November, 1998.     

A kinetics study of the reactions of OH with several aromatic and olefinic compounds

The reactions of hydroxyl radicals with eight substituted aromatic hydrocarbons and four olefins were studied utilizing the flash photolysis–resonance fluorescence technique. The rate constants were measured at 298°K using either Ar or He as the diluent gas. The values of the rate constants (k × 10¹²) in the units of cm³/molec. sec are

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Triterpene glycosides ofHedera helix I. The structures of glycosides L-1, L-2a,L-2b,L-3, L-4a,L-4b,L-6a,L-6b,L-6c,L-7a,and L7-b from the leaves of common ivy

The leaves of common ivy have yielded 11 triterpene glycosides: the 3-O-α-L-pyranosides of oleanolic acid (1), of echinocystic acid (2), and of hederagenin; the 3-O-[O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranoside]s of oleanolic acid (4), of echinocystic acid (5), and of hederagenin (6); the O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester of hederagenin 3-O-α-L-pyranoside (7); the O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester of hederagenin 3-O-[O-α-L-pyranosyl-(1→2)-α-L-arabinopyranoside] (9); and the O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl esters of oleanolic acid, echinocystic acid, and hederagenin 3-O-[O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside]s (8), (10), and (11), respectively. This is the first time that compounds (1), (2), (5), (7), (9), and (10) have been found in this plant. Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 742–746, November–December, 1994.     

Chemistry of vinylidene complexes

The reactions of Cp(CO)₂Re=C=CHPh (2) with M(PPh₃)₄ (M = Pd, Pt) gave the μ-vinylidene complexes Cp(CO)₂RePd(μ-C=CHPh)(PPh₃)₂ (3) and Cp(CO)₂RePt(μ-C=CHPh)(PPh₃)₂ (1), respectively. The substitution of Ph₂PCH₂PPh₂ (dppm) for the PPh₃ ligands in 1 resulted in the formation of Cp(CO)RePt(μ-C(1)=C(2)HPh)(μ-CO)(dppm) (4). The structure of complex 4 has been determined by single-crystal X-ray diffraction analysis. The structural and spectroscopic characteristics of complexes 1, 3, and 4 were compared with the corresponding parameters of the manganese-containing analogs Cp(CO)₂MnPd(μ-C=CHPh)(PPh₃)₂ (5), Cp(CO)₂MnPt(μ-C=CHPh)(PPh₃)₂ (6) and Cp(CO)₂MnPt(μ-C=CHPh)(dppm) (7).     

Beiträge zur Chemie des Phosphors. 152. Funktionalisierte Cyclotriphosphane des Typs (t-BuP)2PX (X = K,SiMe3, SnMe3, Cl,Br, PCl2, P(t-Bu)Cl,P(t-Bu)I)

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Polarographic analytical determination of Hg(II), Cu(II), Cd(II), As(III), Sb(III), Ti(IV) and U(VI) in the presence of Fe(III)

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OPTICAL ISOMERS OF 2,2′-DIAMINOBIPHENYLBIS(ETHYLENEDIAMINE) COBALT(III) CHLORIDE AND ITS RELATED COMPLEXES1

Abstract

Several cobalt(III) complexes incorporating 2,2′-diaminobiphenyl(dabp) and other 2(2N)- or 4N-type ligands were prepared and resolved by chemical and chromatographic methods: (1) [Co(en)₂(dabp)]Cl₂2H₂O, (2) [Co(l-pn)₂(dabp)] (ClO₄)₃4H₂O, (3) [Co(l-chxn)₂(dabp)](ClO₄)₃3H₂O, (4) α-[Co(trien)(dabp)](ClO₄)₃, (5) α-[Co(2S,9S-dimetrien)(dabp)] (ClO₄)₃ 2H₂O, (6) α-[Co(3S,8S-dimetrien)(dabp)] (ClO₄)₃3H₂O, (7 [Co(tren)(dabp)]Cl₃5H₂O, (8) [Co(bpy)₂(dabp)] Cl₃3H₂O. The complexes (1), (4) and (8) gave one pair of enantiomers, Δ(Λ) and Λ(δ), and the complexes (2) and (3) gave only one Δ-isomer. The absolute configuration of the complexes (5) and (6) was found to be Λ, and that of (7) was not determined because of unsuccessful resolution. The three geometric isomers of the complex (2) were separated and their structures assigned.     

Syntheses of the Enantiomers of γ-Cyclogeranic Acid, γ-Cyclocitral,and γ-Damascone: Enantioselective protonation of enolates

(R)-and (S)-γ-cyclogeranic acid ((R)-and (S)- 9 , resp.) were obtained by resolution of the racemate, and their absolute configurations determined by chemical correlation. The γ-acids (R)-and (S)- 9 were converted into (R)-and (S)-methyl γ-cyclogeranate ((R)-and (S)- 6 , resp.), and (R)-and (S)-γ-damascone ((R)-and (S)- 5 , resp.). A more direct entry to (R)-and (S)- 9 consisted in the enantioselective protonation of a thiol ester enolate with (?)- or (γ)-N-isopropylephedrine((?)- or (γ)- 20 ) and subsequent hydrolysis of the (R)-and (S)-S-phenyl γ-thiocyclogeranate ((R)- and (S)- 24 , resp.; 97% ee). The esters (R)- and (S)- 24 were also used as precursors of (R)- and (S)-γ-damascone ((R)- and (S)- 5 , resp.). Alternatively, (S)- 5 (75% ee) was obtained by enantioselective protonation of ketone enolate 29 with (?)-N-isopropylephedrine ((?)- 20 ). Organoleptic evaluation demonstrated that the (S)-enantiomers of methyl γ-cyclogeranate and γ-damascone are markedly superior to their (R)-enantiomers.     

A study of the structure and properties of mixed-ligand Cu(II) complexes with hexafluoroacetylacetone and methyl-, phenyl-ketoimines

The synthesis and X-ray single crystal study of two mixed-ligand Cu(II) complexes are performed: (CH₃C(NCH₃)CHC(O)CH₃)(CF₃C(O)CHC(O)CF₃)Cu (1) (space group P2₁/c, a = 7.0848(12) Å, b = 17.854(3) Å, c = 11.837(2) Å, β = 100.495(6)°, V = 1472.4(4) ų, Z = 4), (CH₃C(NC₆H₅)CHC(O)CH₃)· (CF₃C(O)CHC(O)CF₃)Cu (2) (space group P-1, a = 9.1119(4) Å, b = 9.6954(4) Å, c = 11.1447(6) Å, α = 113.784(2)°, β = 92.383(2)°, γ = 95.402(2)°, V = 893.52(7) ų, Z = 2). The structures are molecular, formed from neutral mixed-ligand copper complexes. The central copper atom has the (3O+N) coordination environment with average Cu-O distances of 1.948 Å and Cu-N of 1.932 Å; the chelate O-Cu-N angle (average) is 94.0°. In the structures, the complexes are linked into dimeric associates with Cu…Cu distances of 3.197 Å (for 1) and 3.246 Å (for 2). The volatility of mixed-ligand complexes 1 and 2 is in between of that of the starting homo-ligand complexes.