Cis Atoms Research Articles

FeIII in a high-spin state in bis(5-bromosalicylaldehyde 4-ethylthiosemicarbazonato-κ3O,N1,S)ferrate(III) nitrate monohydrate, the first example of such a cationic FeIII complex unit.

The synthesis and crystal structure (100 K) of the title compound, [Fe(C10H11BrN3OS)2]NO3·H2O, is reported. The asymmetric unit consists of an octahedral [FeIII(HL)2]+ cation, where HL- is H-5-Br-thsa-Et or 5-bromosalicylaldehyde 4-ethylthiosemicarbazonate(1-) {systematic name: 4-bromo-2-[(4-ethylthiosemicarbazidoidene)methyl]phenolate}, a nitrate anion and a noncoordinated water molecule. Each HL- ligand binds via the thione S, the imine N and the phenolate O atom, resulting in an FeIIIS2N2O2 chromophore. The ligands are orientated in two perpendicular planes, with the O and S atoms in cis and the N atoms in trans positions. This [Fe(HL)2](anion)·H2O compound contains the first known cationic FeIII entity containing two salicylaldehyde thiosemicarbazone derivatives. The FeIII ion is in the high-spin state at 100 K. In addition, a comparative IR spectroscopic study of the free ligand and the ferric complex is presented, demonstrating that such an analysis provides a quick identification of the degree of deprotonation and the coordination mode of the ligand in this class of metal compounds. The variable-temperature magnetic susceptibility measurements (5-320 K) are consistent with the presence of a high-spin FeIII ion with a zero-field splitting D= 0.439 (1) cm-1.

PH-responsive cisplatin-loaded niosomes: synthesis, characterization, cytotoxicity study and interaction analyses by simulation methodology

Abstract Cisplatin (Cis) is an effective cytotoxic agent, but its administration has been challenged by kidney problems, reduced immunity system, chronic neurotoxicity, and hemorrhage. To address these issues, pH-responsive non-ionic surfactant vesicles (niosomes) by Span 60 and Tween 60 derivatized by cholesteryl hemisuccinate (CHEMS), a pH-responsive agent, and Ergosterol (helper lipid), were developed for the first time to deliver Cis. The drug was encapsulated in the niosomes with a high encapsulation efficiency of 89%. This system provided a responsive release of Cis in pH 5.4 and 7.4, thereby improving its targeted anticancer drug delivery. The noisome bilayer model was studied by molecular dynamic simulation containing Tween 60, Span 60, Ergosterol, and Cis molecules to understand the interactions between the loaded drug and noisome constituents. We found that the platinum and chlorine atoms in Cis are critical factors in distributing the drug between water and bilayer surface. Finally, the lethal effect of niosomal Cis was investigated on the MCF7 breast cancer cell line using 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results from morphology monitoring and cytotoxic assessments suggested a better cell-killing effect for niosomal Cis than standard Cis. Together, the synthesis of stimuli-responsive niosomes could represent a promising delivery strategy for anticancer drugs.

Quaternization and oxidation reactions of cyclodiphosphazane derivatives and their copper(I) and gold(I) complexes.

The reactions of cyclodiphosphazane derivatives cis-{(t)BuN(H)P(μ-N(t)Bu)2PN(H)(t)Bu} (1), cis-{MeN(C4H8N)P(μ-N(t)Bu)2P(NC4H8Me)} (2) and {(Me2NCH2CH2O)P(μ-N(t)Bu)2P(OCH2CH2NMe2)} (3) with methyl iodide and methyl triflate and their subsequent reactions with elemental sulfur and selenium are reported. Interestingly, the reactions of 1-3 with an excess of methyl iodide resulted in quaternising only one phosphorus atom in cis-[{(t)BuNHP(μ-N(t)Bu)2P(CH3)NH(t)Bu}](I) (4), two exocyclic nitrogen atoms and one of the phosphorus atoms in cis-{(Me2NC4H8N)P(μ-N(t)Bu)2P(CH3)(NC4H8NMe2)}](I)3 (7) and only two exocyclic nitrogen atoms in cis-[{(Me3NCH2CH2O)P(μ-N(t)Bu)2P(OCH2CH2NMe3)}](I)2 (8). The reaction of 1 with one equiv. of methyl triflate produced cis-[{(t)BuN(H)P(μ-N(t)Bu)2P(CH3)N(H)(t)Bu}]OTf (5), whereas the same reaction in a 1 : 2 molar ratio afforded cis-{(t)BuN(H)P(CH3)(μ-N(t)Bu)2P(CH3)N(H)(t)Bu}(OTf)2 (6). Compounds 4 and 5 showed poor solubility in water, whereas 7 and 8 were high melting crystalline solids with moderate to good water solubility. Treatment of 4 with either elemental sulfur or selenium gave both cis- and trans-chalcogenide derivatives. Similar reactions of 7 and 8 produced both mono- and bischalcogenides. Reactions between 4 or 7 and CuI yielded dinuclear complexes, cis-[{Cu2(μ-I)3((t)BuN(H)P)(μ-N(t)Bu)2(P(CH3)N(H)(t)Bu)]2}(I)] (15) and cis-[{Cu2(μ-I)3[(Me2NC4H8N)P(μ-N(t)Bu)2P(CH3)(NC4H8NMe2)]2}(I)5] (16), while the reaction of 8 with CuI produced a coordination polymer [{Cu2(μ-I)3(μ-N(t)BuP)2(OCH2CH2NMe3)2}I]∞ (17), containing triiodo-bridged [Cu2(μ-I)3] linkers. The molecular structures of several of these compounds were confirmed by single crystal X-ray diffraction studies. The Cu(I)···Cu(I) distance of 2.55 Å in 15 is quite short and is the same as that found in copper metal and also in complexes containing [Cu2(μ-I)3] linkers. All the metal complexes exhibit strong intra-, inter- or both intra- and inter-molecular hydrogen bonding interactions.

Synthesis and structural characterization of mono- and dinuclear Mo(V)-oxo-complexes containing bis(3,5-dimethylpyrazol-1-yl)acetate anion as ligand

Abstract Reactions of bis(3,5-dimethylpyrazol-1-yl)acetic acid (Hbdmpza) with (pyH)5[MoOCl4(H2O)]3Cl2, and (pyH)[MoOBr4] in acetonitrile at elevated temperatures result in obtaining two new compounds, [MoOX2(bdmpza)]∙yCH3CN (X=Cl y = 0 (1), X=Br, y = 1 (2)), respectively. The treatment of mononuclear 1 and 2 in acetonitrile/water solution gives dinuclear [Mo2O4(bdmpza)2]∙2H2O (3). The complexes were analyzed by elemental analysis UV–Vis and IR spectroscopy. The κ3-N,N,O coordination of Mo atoms by bdmpza was proven by the single-crystal X-ray structure. In all compounds the Mo(V) centers are six-coordinated; in 3 the Mo atoms in cis-{Mo2O4}2+ core are bridged by two O atoms.

Different coordination modes for disulfoxides towards diorganotin(IV) dichlorides. X-ray crystal structures of 1,2-cis-bis-(phenylsulfinyl)ethene (rac-,cis-cbpse) and adducts [{Ph2SnCl2(meso-bpse)}n] and [{n-Bu2SnCl2(pdtd)}2

The reactions of meso-1,2-bis(phenylsulfinyl)ethane (meso-bpse) with Ph2SnCl2, 2-phenyl-1,3-dithiane trans-1-trans-3-dioxide (pdtd) with n-Bu2SnCl2 and 1,2-cis-bis-(phenylsulfinyl)ethene (rac-,cis-cbpse) with Ph2SnCl2, in 1:1 molar ratio, yielded [{Ph2SnCl2(meso-bpse)}n], [{n-Bu2SnCl2(pdtd)}2] and [{Ph2SnCl2(rac,cis-cbpse)}x] (x = 2 or n), respectively. All adducts were studied by IR, Mossbauer and 119Sn NMR spectroscopic methods, elemental analysis and single crystal X-ray diffractometry. The X-ray crystal structure of [{Ph2SnCl2(meso-bpse)}n] revealed the occurrence of infinite chains in which the tin(IV) atoms appear in a distorted octahedral geometry with Cl atoms in cis and Ph groups in trans positions. The X-ray crystal structure of [{n-Bu2SnCl2(pdtd)}2] revealed discrete centrosymmetric dimeric species in which the tin(IV) atoms possess a distorted octahedral geometry with bridging disulfoxides in cis and n-butyl moieties in trans positions. The spectroscopic data indicated that the adduct containing the rac,cis-cbpse ligand can be dimeric or polymeric. The X-ray structural analysis of the free rac-,cis-cbpse sulfoxide revealed that the crystals belong to the C2/c space group.

Crystal structure of trans-dichloro-1,3-propanediamine-bis[(2-methoxyethyl) diphenylphosphine]ruthenium (II),RuCl2(C3H10N2)(C15H17OP)2

Article Crystal structure of trans-dichloro-1,3-propanediamine-bis[(2-methoxyethyl) diphenylphosphine]ruthenium (II),RuCl2(C3H10N2)(C15H17OP)2 was published on April 1, 2006 in the journal Zeitschrift für Kristallographie - New Crystal Structures (volume 221, issue 1-4).

Crystal structure of cis,cis,cis‐1,2‐epoxy‐3,5‐dibromo‐4‐hydroxy tetralin

AbstractThe title compound, C10H8Br2O2, consists of a tetrahydronaphthalene skeleton composed of a six‐membered ring A with arene oxide, monobromo and monohydroxy atoms in cis,cis,cis configuration held in a boat conformation and a six‐membered planar ring B, where the ring B carries monobromo atom. The repulsive interactions between the Br and OH atoms affect the topology of the tetrahydronaphthalene moieties.

Synthesis, crystal structure and magnetic properties of the manganese(II) chains [Mn(bipym)(NO3)2] and [Mn(bipym)(NCO)2] (bipym = 2,2′-bipyrimidine)

Two new manganese(II) chains of formula [Mn(bipym)(NO 3 ) 2 ] 1 and [Mn(bipym)(NCO) 2 ] 2 (bipym = 2,2′-bipyrimidine) have been synthesized and their structures determined by single-crystal X-ray diffraction. Their structures consist of zigzag chains of bipym-bridged manganese(II) ions where electroneutrality is achieved by monodentate and chelating nitrate groups (1) and by N-bonded terminal cyanate ligands (2). The manganese atom in 1 is seven-co-ordinated being surrounded by four bipym nitrogens and three nitrato-oxygens [Mn–N and Mn–O 2.362(2)–2.330(2) and 2.205(2)–2.392(2) A, respectively]. The manganese atom in 2 is six-co-ordinated with four bipym- and two cyanato-nitrogen atoms in cis position comprising a distorted-octahedral environment [average Mn–N (cyanato) and Mn–N (bipym) bond distances 2.097(3) and 2.355(3) A, respectively]. In both structures the bipym group acts as a bis(bidentate) ligand forming two five-membered chelate rings, the values of the bite angle at the bipym being 69.5(1) and 69.3(1)° in 1 and 69.5(1)° in 2. The intrachain metal–metal separations are 6.239(1) and 6.247(1) A in 1 and 6.234(1) A in 2. Variable-temperature magnetic susceptibility data in the temperature range 290–4.2 K show the occurrence of a significant intrachain antiferromagnetic coupling between the local high-spin manganese(II) ions, the values of the exchange coupling parameter J being -0.93 (1) and -1.1 (2) cm -1 . The efficiency of bis(chelating) ligands such as bipym and oxalate in mediating antiferromagnetic coupling between manganese(II) ions is analysed and discussed in the light of available magnetostructural data.

X-ray crystal structures ofcis-bis(diphenylphosphinamide)tetracarbonylmolybdenum(0) andtrans-bis(N-methyl diphenylphosphinamide)tetracarbonylmolybdenum(0)

The X-ray crystal structures ofcis-Mo(CO)4(Ph2PNH2)2,I, andtrans-Mo(CO)4(Ph2PNHMe)2,II, are presented. ComplexI crystallizes in the monoclinic space groupP21/c(a=13.433(1),b=12.2719(8),c=17.318(2)A;β=109.79(1)°;V=2686.1(8)A3;Z=4). ComplexII crystallizes in the triclinic space groupP¯1 (a=6.9986(8),b=10.328(1),c=11.241(2)A,α=107.58(1)°,β=91.76(1)°, γ=101.28(1)°,V=756.1(4)A3,Z=1). The molybdenum coordination geometry in each complex is a slightly distorted octahedron. The molybdenum-carbon bond lengths for the carbonyls trans to phosphorus in complexI are shorter than those the carbonyls trans to other carbonyls. The average molybdenum-phosphorus distance inI (2.525(5)A) is similar to those in other diphenylphosphinamide complexes and longer than the molybdenum-phosphorus distance inII in 2.4585(7)A). The distance between two nitrogen atoms incis Mo(CO)4(Ph2PNH2)2 (3.74(3)A) is significantly larger than the sum of their van der Waals radii (3.10 A) indicating that the two nitrogens are not hydrogen bonded.

Synthesis and structures of copper(II) and nickel(II) complexes of 1,8-diaza-4-thiaoctane. Characterization of a novel polymeric trigonal bipyramidal copper(II) complex containing both bridging and meridionally coordinated ligands

The synthesis, x-ray structure determination, and spectroscopic properties of nickel(II) and copper(II) complexes of 1,8-diaza-4-thiaoctane (aeaps) are described. [Ni(aeaps)2](ClO4)2 crystallizes in the orthorhombic space group Pbcn witha=10.943(2),b=13.209(2),c=14.798(2)A, and Z=4. The complex crystallizes as the unsymmetrical facial isomer, with the sulfur atoms incis positions. The copper(II) complex crystallizes in the monoclinic space group Cc, witha=16.041(2),b=9.223(1),c=16.048(3) A,a=118.65(2)0, and Z=4. The copper(II) ion has a trigonal bipyramidal coordination geometry, with one ligand coordinated meridionally, and two bridging ligands in which the thioether is not bound to a metal ion. The structures of these complexes are discussed in terms of the known solution chemistry of this ligand with copper(II) and nickel(II).

Synthesis and crystal structure of complex compounds of oxyhalogenide Mo(V) and oxythiohalogenide Mo(VI) with triphenylphosphine oxide

From a study of the interaction of MoSCl/sub 3/ with OP(C/sub 6/H/sub 5/)/sub 3/ (L) we established the conditions for synthesis and isolated complexes of composition (MoOCl/sub 3/L/sub 2/)-(Mo(O, Cl)/sub 2/Cl/sub 2/L/sub 2/) (I) and (MoO/sub 2/Cl/sub 2/L/sub 2/)(MoOSCl/sub 2/L/sub 2/) (II) in the form of single crystals. The crystals were monoclinic with almost identical unit cells but were different in color. It transpired that the structure of I agreed with that carried out in (1) and confirmed the heterovalent statistical distribution found by the authors for the Cl and O atoms occupying the two vertices of one of the two crystallographically independent Mo octahedra. Complex II is isostructural with I. The Mo atom is coordinated by two Cl atoms in trans positions, and by two O/sub L/ cis atoms. O and S are situated in trans positions to the two O/sub L/ atoms in Mo(1) whereas in Mo(2) octahedra these positions are occupied by two oxo atoms. Distances are Mo(2)-O/sub L/ 2.18(1) and 2.17(1) A, Mo(1)-O/sub L/ 2.10(2) and 2.16(1) A, Mo(2)=O 1.74 (2) and 1.77(1), Mo(1)=O 1.67 (1), Mo(1)=S 2.249(7), Mo(1)-Cl 2.396 (6) and 2.386(6), Mo(2)-Cl 2.394(6) and 2.378(6) A. The difference in the bond lengths Mo(1)-O/sub L/more » for the two L molecules is probably linked to the trans effect of the ligands.« less

Reactions involving transition metals. Part 16. Rhodium, iridium, platinum, and gold complexes containing the bis(trifluoromethyl)amino-oxy-ligand

The stable complexes [Ir{ON(CF3)2}2Cl(CO)L2](L = PPh3, AsPh3, or PMePh2) and [Pt{ON(CF3)2}2(PPh3)2] have been prepared by oxidative addition of the radical (CF3)2NO˙ to trans-[IrCl(CO)L2] and either [Pt(η2-C2H4)(PPh3)2] or [Pt(PPh3)4] respectively. The compounds trans-[IrX(CO)(PPh3)2](X = Br or I) react with the radical to give a mixture of [Ir{ON(CF3)2}2{CO2N(CF3)2}(PPh3)2] and [IrX3(CO)(PPh3)2]. The platinum(II) complexes [Pt{ON(CF3)2}2L2](L = PPh3, AsPh3, or PMePh2) and the gold(I) complex [Au{ON(CF3)2}(PPh3)] have been synthesized by metathetical exchange of the chlorine atoms in cis-[PtCl2L2] and [AuCl(PPh3)] using [Hg{ON(CF3)2)}2]. The weak nucleophile Na[ON(CF3)2] has been shown to react with the complexes [M(CO)(MeCN)(PPh3)2]ClO4(M = Rh or Ir) to give the compounds trans-[M{ON(CF3)2}(CO)(PPh3)2], while reaction with the complexes trans-[PtX(CO)L2]BF4(X = Cl, L = PPh3 or AsPh3; X = Br, L = PPh3) occurs at the carbonyl ligand giving [PtX{CO2N(CF3)2}L2]. The new iridium(I) complex trans-[Ir{ON(CF3)2}(CO)(PPh3)2] forms an oxygen complex in solution, and reacts with halogens, CF3CO2H, HgCl2, and C6H5CH2COCl to give the products [IrX3(CO)(PPh3)2](X = Cl or l), [IrH(O2CCF3)2(CO)(PPh3)2], [IrCl2(HgCl)(CO)(PPh3)2], and [IrCl2(COCH2C6H5)(CO)(PPh3)2] respectively, with loss of the (CF3)2NO ligand; unstable oxidative-addition products [Ir{ON(CF3)2}(R)l(CO)(PPh3)2](R = CF3, CH3, or C2H5) have been characterized from the reactions with iodoalkanes.

On the radiation induced solid state isotopic exchange reactions between 60Co 2+ dopant ions and Co(III) atoms in cis-[Coen 2(NO 2)CNS][Co EDTA] 2H 2)

On the radiation induced solid state isotopic exchange reactions between 60Co 2+ dopant ions and Co(III) atoms in cis-[Coen 2(NO 2)CNS][Co EDTA] 2H 2)

Cyclic inorganic compounds. Part IX. Fluorination of bisdimethylaminotetrachlorotriphosphonitrile

Substitution of two of the chlorine atoms in cis-(Ia) and trans-1,3-bisdimethylaminotetrachlorotriphosphonitrile (Ib), with potassium fluorosulphite yields the corresponding cis-(IIa) and trans-geminal (5,5) difluorides(IIb). With antimony trifluoride as fluorinating agent, only the chlorine atoms in the 1- and 3-positions are substituted and two further isomeric difluorides,(IIIa) and (IIIb), can be obtained. Structures are proposed on the basis of 1H and 19F n.m.r. spectra together with evidence from i.r. spectroscopy. Further fluorination of the 1,3-difluorides (IIIa), and (IIIb) with either potassium fluorosulphite or sodium fluoride gives two isomeric 1,3,5,5-tetrafluorides (IVa) and (IVb).