Reactions of organotin chlorides R2SnCl2 (R = Et, But, or Ph) with lithium 4,6-di( tert -butyl)- N -(2,6-diisopropylphenyl)- o -amidophenolate. Synthesis and structures of tin( IV ) o -iminoquinone complexes

The exchange reactions of tin diorganohalides R₂SnCl₂ (R = Et, Bu^t, or Ph) with lithium amidophenolate APLi₂ (AP is the 4,6-di(tert-butyl)-N-(2,6-diisopropylphenyl)-o-iminobenzo-quinone dianion) in tetrahydrofuran produced the new five-coordinate (Et₂SnAP(THF) (3)) and four-coordinate (R₂SnAP (R = Bu^t, Ph)) tin(IV) complexes. The reaction of Ph₂SnCl₂ with APLi₂ in a nonpolar solvent (hexane or toluene) is accompanied by the additional redox process giving rise to the paramagnetic complex Ph₂Sn(ImSQ)Cl (6) (ImSQ is the 4,6-di(tert-butyl)-N-(2,6-diisopropylphenyl)-o-iminobenzoquinone radical anion). The molecular structures of complexes 3 and 6 were established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 253–258, February, 2007.     

Beiträge zur Chemie des Phosphors. 87. 1,2-Di-tert-butyl-3-iso-propyl-cyclotriphosphan,ein stabiles gemischt-substituiertes Cyclotriphosphan

Contributions to the Chemistry of Phosphorus. 87. 1,2-Di-tert-butyl-3-iso-propyl-cylclotriphosphane, a Stable Mixed-substituted Cyclotriphosphane The first kinetically stable mixed-substituted cyclotriphosphane, 1,2-di-tert-butyl-3-iso-propyl-cyclotriphosphane, (PBu^t)₂(PPrⁱ) ( 1 ), was synthesized by [2+1]-cyclocondensation of K(Bu^t)P–P(Bu^t)K with PrⁱPCl₂ in n-pentane. Mainly (PBu^t)₄ as well as mixed-substituted cyclotetra- and cyclopentaphosphanes are formed as by-products. 1 could be isolated in a pure state by high vacuum distillation and was thoroughly characterized. It forms two diastereomers, the more stable of which with a cis-standing tert-butyl and iso-propyl group can be stored without decomposition under inert conditions at room temperature for several days. Through thermolysis of 1 beside other alkylcyclophosphanes the mixed-substituted cyclotetraphosphanes (PBu^t)₂(PPrⁱ)₂ ( 2 ) and (PBu^t)₃(PPrⁱ) ( 3 ) are formed and their ³¹P NMR parameters are reported.     

Syntheses,structural determination,and binding studies of nine-coordinate multinuclear (mnH)2[EuIII(egta)]2·6H2O and binuclear (mnH)4[EuIII2(dtpa)2]·6H2O

Two lanthanide complexes, (mnH)₂[Eu^III(egta)]₂·6H₂O (1) (H₄egta = ethyleneglycol-bis-(2aminoethylether)-N,N,N′,N′-tetraacetic acid) and (mnH)₄[Eu^III₂(dtpa)₂]·6H₂O (2) (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), have been synthesized and characterized by FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray diffraction reveals that 1 is multinuclear nine-coordinate and crystallizes in the monoclinic crystal system with space group C2/c. The obtained cell dimensions are a = 38.513(3)?Å, b = 13.5877(8)?Å, c = 8.7051(5)?Å, β = 99.6780(10)°, and 4490.6(5)?ų. Each methylamine (mnH⁺) cation in 1, through hydrogen bonds, connects three adjacent [Eu^III(egta)]^? anions. The [Eu^III(egta)]^? anions connect one another forming a 1-D multinuclear zigzag chain structure along the c-axis. Complex 2 is nine-coordinate binuclear structure with tricapped trigonal prismatic conformation and crystallizing in the monoclinic crystal system, but with space group P2₁/n. The obtained cell dimensions are a = 9.9132(8)?Å, b = 24.1027(18)?Å, c = 10.7120(10)?Å, β = 109.1220(10)°, and 2418.2(3)?ų. For 2, there are two kinds of methylamine cations (mnH⁺) connecting [Eu^III₂(dtpa)₂]^4? complex anions and lattice waters through hydrogen bonds, leading to formation of a 2-D ladder-like layer structure.     

Synthesis, crystal structure and spectroscopic properties of two new complexes containing azido or dicyanamido bridges

Two new complexes, [Cu(L₁){N(CN)₂}]·ClO₄ (1) (L₁ is 1,8-dimethyl-1,3,6,8,10,13-hexa-azacyclotetradecane) and [Co(L₂)(N₃)₂]·ClO₄ (2) (L₂ is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetra-azacyclotetradecane) have been synthesized and characterized. The compounds crystallize in the monoclinic system P2₁ space group for 1 and P2₁/n for 2. Single crystal X-ray analysis reveals that the compound 1 assumes a one-dimensional structure via hydrogen-bonding interactions, in which each Cu(II) ion is coordinated by four nitrogen atoms from ligand L₁ and one nitrogen atom from [N(CN)₂]⁻ anion. For compound 2, each Co(III) ion is coordinated by four nitrogen atoms of ligand L₂ and two nitrogen atoms from N₃ ⁻ anion.     

The synthesis and characterization of a new (E,E)-dioxime containing 20-membered tetraazadioxa macrocyclic moieties and its mononuclear complexes

A new (E,E)-dioxime, (2Z,3Z)-9,20-bis[(4-methylphenyl)sulfonyl]-1,4,7,8,9,10,11,12,14,15,17, 18,19,20,21,22-hexadecahydro-13,16-ethano[1,4,7,11,14,18]dioxatetraazacycloicosino[2,3-g] quinoxaline-2,3-dione dioxime (6) (H₂L) has been synthesized by reacting cyanogen-di-N-oxide (5) with 4,15-bis[(4-methylphenyl)sulfonyl]-2,3,4,5,6,7,9,10,12,13,14,15,16,17-tetradecahydro-8,11-ethano-1,18,4,8,11,15-benzodioxatetraazacycloicosine-20,21-diamine (4). Mononuclear complexes (7) and (8) of this ligand have been synthesized by reacting the vic-dioxime (H₂L) with NiCl₂.6H₂O and CoCl₂.6H₂O respectively. The BF₂⁺ capped Ni(II) and Co(III) complexes (9) and (10) of the dioxime have been synthesized from (7) and (8), respectively. The new compounds were characterized by a combination of elemental analysis, ¹H- and ¹³C-NMR, IR. and MS. spectral data.     

两种3D微孔Zn-MOF对水溶液中Fe3+、Cr2O72-和丙酮分子的荧光传感(英文)

通过溶剂热法合成了2种三维微孔锌金属有机框架材料,其分子式为[Zn₃(DBA)(OH)(1,10-phen)₂]_n (1)和{[Zn₂(HDBA)(4,4′-bipy)_1.5]·H₂O}_n (2)(H₅DBA=3,5-二(2′,4′-对羧基苯基)苯甲酸;1,10-phen=1,10-菲咯啉;4,4′-bipy=4,4′-联吡啶)。结构分析表明,配合物1为三核锌基金属单元的三维微孔骨架,配合物2为双核锌基的微孔结构。与2相比,配合物1在水中具有较强的发光性能,可作为检测Fe³⁺、Cr₂O₇^2-和丙酮分子的发光传感器,具有较高的选择性和灵敏度。     

Diorganotin Complexes with N(4)-Phenylthiosemicarbazones: Synthesis,Spectroscopic Characterization,and Antibacterial Activity

Abstract

The organotin(IV) complexes, SnPh₂L^a (1), SnMe₂L^a (2), SnBu₂L^a (3), SnPh₂L^b (4), SnMe₂L^b (5), SnPh₂L^c (6), SnMe₂L^c (7), and SnBu₂L^c (8) were obtained by reaction of SnR ₂Cl₂ (R = Ph, Me, and Bu) with 1-(5-bromo-2-hydroxybenzylidene)-4-phenylthiosemicarbazide (H₂L^a), 1-((2-hydroxynaphthalen-1-yl)methylene)-4-phenylthiosemicarbazide (H₂L^b), and 1-(2-hydroxy-3-methoxybenzylidene)-4-phenylthiosemicarbazide (H₂L^c). The synthesized complexes have been investigated by elemental analysis, IR, ¹H NMR, and ¹¹⁹Sn NMR spectroscopy. The data show that the thiosemicarbazone acts as a tridentate dianionic ligand and coordinates via the thiol group, imine nitrogen, and phenolic oxygen. The coordination number of tin is 5. The in vitro antibacterial activities of the ligands and their complexes have been evaluated against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and compared with the standard antibacterial drugs.

[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 following free supplemental files: Additional figures and tables]     

SCHWEFELDIIMIDE MIT SILYL-, GERMYL-, STANNYL- UND PHOSPHINYL-HETEROSUBSTITUENTEN. SYNTHESE UND NMR-SPEKTROSKOPISCHE CHARAKTERISIERUNG

Abstract

Reactions of the salts K₂SN₂ and K[(NSN)R] (R = ′Bu, SiMe₃ and P′Bu₂) with organoelement chlorides R′R′ěl have been used to prepare four series of model sulfur diimides: R′R″E(NSN)ER″R′, ′Bu(NSN)ER″R′, Me₃Si(NSN)E″R′ and ^tBu₂P(NSN)ER″R′, respectively (E = C, Si, Ge, Sn; R′ and R″ = alkyl or aryl group). All compounds have been characterized by ′H and ¹³C NMR and—if possible—by ³¹P, ²⁹Si and ¹¹⁹Sn NMR spectroscopy. The configuration (Z or E) of the substituents R and E″R′ has been assigned in several cases using ^tBu(NSN)^tBu (1) as a reference. The E,Z assignment of ¹H, ¹³C and ¹⁵N nuclei in 1 is based on selectively ¹H-decoupled refocused INEPT ¹⁵N NMR and two-dimensional (2D) ¹³C/¹H heteronuclear shift correlations. The sulfur diimides under study are in general fluxional in solution.     

ESR study of the thermal decomposition of di-tert-butoxy-tert-butyl alumotrioxide formed in the reaction of tri-tert-butoxyaluminum with tert-butyl hydroperoxide

Tri-tert-butoxyaluminum reacts with tert-butyl hydroperoxide to produce di-tert-butoxy-tert-butyl alumotrioxide, which decomposes heterolytically to form singlet dioxygen and homolytically with the O—O bond cleavage. The Bu^tOO^·, (Bu^tO)₂AlOO^·, Bu^tO^·, and (Bu^tO)₂AlO^· radicals were identified by ESR using spin traps. These findings confirm the formation of aluminum-containing trioxide. The above radicals initiate alkylarene oxidation by the tri-tert-butoxyaluminum—tert-butyl hydroperoxide system. The carbon-centered and alkylperoxy radicals originated from the oxidized substrates were identified.     

Synthesis and cation binding properties of fluorescent calix[4]arene derivatives bearing tryptophan units at the lower rim

The fluorescent peptidocalixarenes, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(O-methyl-l-tryptophanylcarbonylmethoxy)calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,27-di(O-methyl)-26,28-bis(O-methyl-l-tryptophanylcarbonylmethoxy)calix[4]arene (2), were prepared by introducing tryptophan subunits at a lower calixarene rim. Coordination abilities of 1 and 2 towards Eu(III) and alkali metal cations were studied by spectrophotometric, spectrofluorimetric, conductometric and potentiometric titrations in acetonitrile at 25°C. Rather strong complexation was observed for smaller alkali metal cations Li⁺ and Na⁺ (log K _Li1 >6, log K _Li2 >6, log K _Na1  = 8.25, log K _Na2  = 6.94), and moderate for K⁺ (log K _K1  = 5.09, log K _K2  = 4.09). Larger Rb⁺ and Cs⁺ cations did not fit in the ion binding site of 1 so no complexation was detected, whereas the more flexible ligand 2 accommodated Rb⁺ cation (log K _Rb2  = 3.44). The fluorescence of 1 (λ_ex = 280 nm, λ_em = 340 nm) was remarkably quenched by Eu(III). Stability constant of 1:1 (Eu³⁺:1) complex determined spectrofluorimetrically amounted to log K _Eu1  = 6.16.     

Synthesis,characterization, and crystal structures of cobalt(II), copper(II), and zinc(II) complexes of a bidentate iminophenol

A bidentate iminophenol (HL = 2-((4-methoxyphenylimino)methyl)-4,6-di-tert-butylphenol derived from condensation of 4-methoxyaniline and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) was mixed with divalent metal salts to form the corresponding mononuclear metal complexes [M^II(L)₂] (M = Co (1), Cu (2), and Zn (3)). The complexes are characterized by different spectroscopic and analytical tools. X-ray crystal structures of the complexes revealed homoleptic mononuclear complexes with MN₂O₂ coordination. The cobalt(II) (1) and zinc(II) (3) complexes display a pseudo-tetrahedral coordination geometry, whereas the copper(II) complex (2) exhibits a distorted square-planar coordination. The zinc(II) complex (3) emits at 460 nm with a twofold enhancement of emission with respect to the free iminophenol.     

Cyclization of N-alkyldithiocarbamates in alkaline media,a counter example of well-known chemistry – an experimental and theoretical study

In strong alkaline media, the reaction of 2-(tert-butylamino)ethanol (3: R?=?Bu^t) with CS₂ at 0°C produced a cyclic dithiocarbamate, 3-tert-butylthiazolidine-2-thione (1: R?=?Bu^t), rather than alkaline metal or ammonium salts of [S₂CN(Bu^t)CH₂CH₂OH]^?. This is in contrast to isolation of stable alkaline metal or ammonium salts of [S₂CN(R)CH₂CH₂OH]^? (R?=?Me, Et, Pr, or CH₂CH₂OH) obtained in analogous reactions. The use of Ni(OAc)₂, both as a source of Ni(II) and a weaker base, in a one-pot reaction with (3: R?=?Bu^t) and CS₂, successfully gave the first reported metal complex of [S₂CN(Bu^t)CH₂CH₂OH]^?, namely [Ni{S₂CN(Bu^t)CH₂CH₂OH}₂] (2: R?=?Bu^t). Compounds 1 and 2 have been fully characterized by infrared and NMR spectroscopies, and by X-ray crystallography. DFT calculations on the cyclization and stabilities of [S₂CN(R)CH₂CH₂OH]^? (R?=?Pr and Bu^t) have been carried out.     

Reactions of tBu2P–PLi–PtBu2 with [(Et3P)2MCl2] (M = Ni,Pd, Pt). Synthesis and Properties of [(1,2‐η‐tBu2P=P–PtBu2)M(PEt3)Cl] (M=Ni,Pd)

^tBu₂P–PLi–P^tBu₂·2THF reacts with [cis‐(Et₃P)₂MCl₂] (M = Ni, Pd) yielding [(1,2‐η‐^tBu₂P=P–P^tBu₂)Ni(PEt₃)Cl] and [(1,2‐η‐^tBu₂P=P–P^tBu2)Pd(PEt₃)Cl], respectively. ^tBu₂P– PLi–P^tBu₂ undergoes an oxidation process and the ^tBu₂P–P–P^tBu₂ ligand adopts in the products the structure of a side‐on bonded 1,1‐di‐tert‐butyl‐2‐(di‐tert‐butylphosphino)diphosphenium cation with a short P–P bond. Surprisingly, the reaction of ^tBu₂P–PLi–P^tBu₂·2THF with [cis‐(Et₃P)₂PtCl₂] does not yield [(1,2‐η‐^tBu₂P=P–P^tBu₂)Pt(PEt₃)Cl].     

Modification,characterization and peroxidase-mimetic properties of calcined product of a cobalt compound

One-pot solvothermal treatment of Co(NO₃)₂·6H₂O, H₂L (5-(3-methyl-5-(pyridin-4-yl)-4H-1,2,4-triazol-4-yl) isophthalic acid), and 4,4′-bipyridine (4,4′-bipy) in H₂O/DMF (V/V = 1?:?1) yielded a cobalt-organic chain, [Co(L)(O)(H₂O)₂]_n·1.25nH₂O (1). Compound 1 as raw materials was calcined to obtain Co₃O₄, which could be confirmed by PXRD and SEM. Via the modification, Co₃O₄@SiO₂-NH₂ and Co₃O₄@SiO₂-NH₂-FA samples could be obtained. Compared to Co₃O₄@SiO₂-NH₂, Co₃O₄@SiO₂-NH₂-FA seems to have better peroxidase-mimetic properties. UV–vis results showed that optimal conditions of peroxidase-mimetic experiments were at 50°C in sodium acetate-acetic acid buffer (pH 3.6, 0.2 M), when the concentration of tetramethylbenzidine (TMB) was 0.2 mM. A concentration-dependent manner was shown between the concentration of glucose and absorbance in the measurement experiments for glucose.     

Acetate platinum(II) compound with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine that overcomes cisplatin resistance: structural characterization,in vitro cytotoxicity,and kinetic studies

The reaction of silver acetate with cis-[PtI₂(dbtp)₂], where dbtp = 5,7-ditertbutyl-1,2,4-triazolo-[1,5-a]pyrimidine, yielded cis-[Pt(OOCCH₃)₂(dbtp)₂]·dmf (1). The complex has been analyzed by multinuclear magnetic resonance (¹H, ¹³C, ¹⁵N), IR, and Raman. The compound formed two rotamers in CDCl₃ and its spatial structures have been optimized using computational calculation. It was found that head-to-tail rotamer (1a) is more stable than its head-to-head counterpart (1b). In vitro antiproliferative activity against four tumor cell lines (A549, T47D, FaDu, and A2780cis) revealed in all cases significant cytotoxicity (IC₅₀ = 0.26–1.80 μM), possessing IC₅₀ values at least fivefold lower than cisplatin, carboplatin, and oxaliplatin (except A2780cis). The remarkable in vitro activity against T47D and A2780cis suggested the ability to overcome cisplatin resistance in these types of tumor cells. In addition, in vitro toxicity was evaluated against BALB/3T3 and has shown that the lipophilic platinum(II) complex (1) inhibits cell proliferation weaker than cisplatin and oxaliplatin. Additionally, cis-[Pt(OOCCH₃)₂(dbtp)₂]·dmf exhibited selective activity, in contrast to cisplatin or oxaliplatin.     

Iron(II) complexes containing the 2,6-bis-iminopyridyl moiety. Synthesis,characterization, reactivity,and DNA binding

Two iron(II) complexes, [Fe^II(py^tBuN₃)₂](FeCl₄) (1) and [Fe^II(py^tBuMe₂N₃)Cl₂] (2), with sterically constrained py^tBuN₃ and py^tBuMe₂N₃ chelate ligands (py^tBuN₃ = 2,6-bis-(aldiimino)pyridyl; py^tBuMe₂N₃ = 2,6-bis-(ketimino)pyridyl), have been synthesized and characterized by elemental analysis, IR, UV–vis spectra, and preliminary X-ray single-crystal diffraction. The latter revealed that Fe(II) in 1 is six-coordinate by six nitrogen donors from two bisiminopyridines in a distorted octahedron. Complex 2 reacts with thiourea with a second-order rate constant k₂ = (2.50 ± 0.05) × 10^?3 M^?1 s^?1 at 296 K, and the reaction seemed to be slow. In a similar way, the interaction of 2 and DNA was studied by fluorescence and absorption spectroscopy. The results revealed that 2 caused fluorescence quenching of DNA through a dynamic quenching procedure. The binding constants K_A, K_app, and K_SV as well as the number of binding sites between 2 and DNA were determined.     

Palladium(II) complexes of (t-butyl salicylidene) diphenyl disulfide diamine: synthesis,structure, spectral characterization and catalytic properties

The hexadentate N₂S₂O₂ donor ligand N,N’-bis(3,5-tert-butylsalicylidene) diphenyl disulfide-2,2’-diamine was synthesised by the condensation of 2-aminophenyl disulfide and 3,5-di-tert-butyl-2-hydroxybenzaldehyde and its molecular structure was confirmed by X-ray studies. One of the tert-butyl groups in the Schiff base has rotational disorder around the C–C bond with ratio 0.56:0.44. The palladium complexes were prepared by the direct reaction of PdCl₂(CH₃CN)₂ and Schiff base ligands N,N’-bis (5-tert-butylsalicylidene) diphenyl disulfide-2,2’-diamine and N,N’-bis(3,5-tert-butylsalicylidene) diphenyl disulfide-2,2’-diamine, respectively. The structure of the metal complexes was characterized by physico-chemical and spectroscopic methods. Palladium is in square-planar geometry bonded to imine nitrogen and phenolic O in both the complexes. The catalytic efficiency of the palladium complexes was evaluated in the cross-coupling reactions; Heck-Mizoroki reaction of iodobenzene and methyl acrylate and the Suzuki-Miyaura reaction of phenylboronic acid and iodobenzene, which gave low to moderate yields. Higher conversions were obtained for 2a as catalyst due to the increase in the number of bulky tertiary butyl groups in the structure.

     

Crown-ether styryl dyes

The surface enhanced Raman scattering (SERS) spectra of styryl dyes containing a crown-ether group and a heteroaromatic residue with sulfoalkyl (1a) or alkyl (1b)N-substituent and of their complexes with Mg²⁺ cations were recorded in the 10^–4–10^–8 mol L^–1 concentration range. A model for the interaction of compoundsla,b with a silver surface during their adsorption on an electrochemically treated electrode was suggested. Fastcis-trans relaxation of the adsorbed molecules1a,b and complexes (1a,b)Mg²⁺ was found. It was shown that at [1a] = 10^–5 mol L^–1 and moderate molar ratios (C _Mg/[1a] = 3/1 to 9/1) in acetonitrile solutions, (trans-1a)Mg²⁺ complexes are joined into head-to-tail type dimers. An excess of Mg²⁺ cations (C_Mg/[1a] > 100) leads to dissociation of the dimers yielding (trans-1a)(Mg²⁺)₂ complexes. The formation of dimers from complexes (trans-1a)Mg²⁺ is accompanied by a substantial distortion of the planar structure oftrans-1a. This may be an important factor influencing the efficiency of photocycloaddition involving dimers of (trans-1a)Mg²⁺.For part 15, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2429–2436, December, 1995.The work was carried out with financial support of the Russian Foundation for Basic Research (Project No. 94-03-08760) and, to some extent, of INTAS (Grant No. 93-1829) and of the International Science Foundation (Grant No. MHAOOO).     

Zinc(II) and cadmium(II) complexes having racemic and enantiomeric ligands: [Zn(La)2](NO3)2 · CH3CH2OH and [Cd(Lb)2Cl](ClO4) (La = D,L and Lb = D-(+)-1,2, 2-trimethylcyclopentane-1,3-diamine)

Two d¹⁰ transition-metal complexes having racemic and enantiomeric 1,2,2-trimethylcyclopentane-1,3-diamine ligands, [Zn(L_a)₂](NO₃)₂ · CH₃CH₂OH (1) and [Cd(L_b)₂Cl](ClO₄) (2) (L_a = D,L-1,2,2-trimethylcyclopentane-1,3-diamine, L_b = D-(+)-1,2,2-trimethylcyclopentane-1,3-diamine or (1R,3S)-1,2,2-trimethylcyclopentane-1,3-diamine), were synthesized and characterized by X-ray single-crystal diffraction. They crystallize in the Pbca and P2₁2₁2₁ space groups, respectively, and have different coordination numbers and coordination geometry (four-coordinate tetrahedron for Zn(II) in 1 and five-coordinate square-based pyramid for Cd(II) in 2) mainly due to their different ionic radii.