Synthesis and characterization of di‐n‐butyltin(IV) complexes with 4′/2′‐nitrobiphenyl‐2‐carboxylic acids: X‐ray crystal structures of [{(n‐C4H9)2Sn(OCOC12H8NO2−4′)}2O]2 and (n‐C4H9)2Sn{OCOC12H8NO2−4′}2

Reactions of di‐n‐butyltin(IV) oxide with 4′/2′‐nitrobiphenyl‐2‐carboxylic acids in 1 : 1 and 1 : 2 stoichiometry yield complexes [{(n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′/2′)}₂O]₂ ( 1 and 2 ) and (n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′/2′)₂ ( 3 and 4 ) respectively. These compounds were characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy. The IR spectra of these compounds indicate the presence of anisobidentate carboxylate groups and non‐linear C? Sn? C bonds. From the chemical shifts δ (¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn), the coordination number of the tin atom and the geometry of its coordination sphere have been suggested. [{(n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′)}₂O]₂ ( 1 ) exhibits a dimeric structure containing distannoxane units with two types of tin atom with essentially identical geometry. To a first approximation, the tin atoms appear to be pentacoordinated with distorted trigonal bipyramidal geometry. However, each type of tin atom is further subjected to a sixth weaker interaction and may be described as having a capped trigonal bipyramidal structure. The diffraction study of the complex (n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′)₂ ( 3 ) shows a six–coordinate tin in a distorted octahedral frame containing bidentate asymmetric chelating carboxylate groups, with the n‐Bu groups trans to each other. The n‐Bu? Sn? n‐Bu angle is 152.8° and the Sn? O distances are 2.108(4) and 2.493(5) Å. The oxygen atom of the nitro group of the ligand does not participate in bonding to the tin atom in 1 and 3 . Crystals of 1 are triclinic with space group P1 and of that of 3 have orthorhombic space group Pnna. Copyright © 2003 John Wiley & Sons, Ltd.     

Self‐assembly of di‐ and triblock PEG‐pentavaline amphiphiles

Nanoparticles formed from amphiphilic block copolymers can be used as drug delivery vehicles for hydrophilic therapeutics. Poly(ethylene glycol) (PEG)‐peptide copolymers were investigated for their self‐assembling properties and as consequent potential delivery systems. Mono‐ and dihydroxy PEGs were functionalized with a pentavaline sequence bearing Fmoc end groups. The molecular weight of the PEG component was varied to evaluate copolymer size and block number. These di‐ and tri‐block copolymers readily self‐assemble in aqueous solution with critical aggregation concentrations (CACs) of 0.46–16.29 μM. At concentrations above the CAC, copolymer solutions form spherical assemblies. Dynamic light scattering studies indicate these aggregates have a broad size distribution, with average diameters between 33 and 127 nm. The copolymers are comprised β‐conformations that are stable up to 80 °C, as observed by circular dichroism. This peptide secondary structure is retained in solutions up to 50% MeOH as well. The triblock copolymers proved to be the most stable, with copolymers synthesized from 10 kDa PEG having the most stable particles. Loading of carboxyfluorescein at 2–5 mol % shows that these copolymers have the potential to encapsulate hydrophilic drugs for delivery applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

The reaction of di‐n‐butyltin oxide with hexafluoro‐2,2‐bis(4‐carboxyphenyl)propane

The reaction of hexafluoro‐2,2‐bis(4‐carboxyphenyl)propane with tetrabutyldipropoxydistannoxane, formed in situ from dibutyltin oxide and n‐propanol in benzene, yields a compound the structure of which is a strained macrocycle with a single dicarboxylate moiety. Copyright © 1999 John Wiley & Sons, Ltd.     

Synthesis and characterization of dimeric organotin compounds {[(ArCH2)2 Sn(2‐quin)]2O}2 and crystal structure of {[(2‐ClC6 H4CH2)2Sn(2‐quin)]2O}2

Ten new dimeric organotin compounds {[(ArCH₂)₂ Sn(2‐quin)]₂O}₂ (Ar = Ph 1 , 2‐ClC₆H₄ 2 , 3‐ClC₆H₄ 3 , 4‐ClC₆H₄ 4 , 2‐FC₆H₄ 5 , 3‐FC₆H₄ 6 , 4‐FC₆H₄ 7 , 4‐BrC₆H₄ 8 , 4‐CNC₆H₄ 9 , 2,4‐Cl₂C₆H₃ 10 ) have been synthesized by dealkylation reactions of 2‐quinH with [(ArCH₂)₃Sn]₂O, and their structures have been characterized by elemental analysis, IR and NMR (¹}H, ¹³C, ¹¹⁹Sn) spectroscopies. The structures of {[(2‐ClC₆H₄CH₂)₂Sn(2‐quin)]₂O}₂ 2 have been determined by X‐ray diffraction. Studies show that compound 2 has a tetranuclear, centrosymmetric dimeric structure, with the endo‐cyclic tin atom five‐coordinated and the exo‐cyclic tin atom six coordinated. Studies also show that the nitrogen atoms of the 2‐quin ligand are coordinating to the tin atom for all the ten compounds. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:152–159, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20194     

The synthesis,NMR (1H, 13C, 119Sn) and IR spectral studies of some di‐ and tri‐organotin(IV) sulfonates: X‐ray crystal structure of [(n‐C4H9)2Sn(OSO2C6H4CH3‐4)2·2H2O]

A number of alkyltin(IV) paratoluenesulfonates, R_nSn(OSO₂C₆H₄CH₃‐4)_4?n (n = 2, 3; R = C₂H₅, n‐C₃H₇, n‐C₄H₉), have been prepared and IR spectra and solution NMR (¹H, ¹³C, ¹¹⁹Sn) are reported for these compounds, including (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), the NMR spectra of which have not been reported previously. From the chemical shift δ(¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn) and ²J(¹H, ¹¹⁹Sn), the coordination of the tin atom and the geometry of its coordination sphere in solutions of these compounds is suggested. IR spectra of the compounds are very similar to that observed for the paratoluenesulfonate anion in its sodium salt. The studies indicate that diorganotin(IV) paratoluenesulfonates, and the previously reported compounds (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), contain bridging SO₃X groups that yield polymeric structures with hexacoordination around tin and contain non‐linear C? Sn? C bonds. In triorganotin(IV) sulfonates, pentacoordination for tin with a planar SnC₃ skeleton and bidentate bridging paratoluenesulfonate anionic groups are suggested by IR and NMR spectral studies. The X‐ray structure shows [(n‐C₄H₉)₂Sn(OSO₂C₆H₄CH₃‐4)₂·2H₂O] to be monomeric containing six‐coordinate tin and crystallizes from methanol–chloroform in monoclinic space group C2/c. The Sn? O (paratoluenesulfonate) bond distance (2.26(2) Å) is indicative of a relatively high degree of ionic character in the metal–anion bonds. Copyright © 2003 John Wiley & Sons, Ltd.     

Tetranuclear clusters containing a CrIII-doped MnIII4O2 core: syntheses, structures, and magnetic properties

The oxidation of MnII carboxylates by (NBu4)Cr2O7 in the presence of different phosphonic acids and chelating ligands results in six CrIII-doped tetranuclear manganese clusters formulated [Mn3CrO2(O2CCH3)4(O3PC5H4N)2(bpy)2] (1), [Mn3CrO2(O2CCH3)4(O3PC5H4N)2(phen)2] (2), [Mn3CrO2(O2CPh)4(O3PC5H4NO)2(phen)2] (3), [Mn3CrO2(O2CPh)4(O3PC6H11)2(bpy)2] (4), [Mn 3CrO2(O2CPh)4(O3PC6H11)2(phen) 2] (5), and [Mn3CrO2(O2CCH3)4(O3PC6H11)2(bpy)2] (6). Single-crystal X-ray analyses reveal that all the compounds contain similar [M4O2]8+ cores with the four metal sites arranged in planar topologies. The metal ions within the core are bridged by both carboxylate and phosphonate ligands. Temperature-dependent magnetic measurements show that in all cases dominant antiferromagnetic interactions are propagated between the metal centers. The ac magnetic measurements on compounds 5 and 6 reveal that both the in-phase and the out-of-phase signals are frequency dependent, characteristic of single-molecule magnet behaviors.     

Synthesis and crystal structure of AlH2P3O10.2H2O; a new structure-type for layered acid phosphates

The crystal structure of the layered acid phosphate, AlH2P3O10.2H2O, has been determined and provides a new structure-type for a series of metal phosphates with interlamellar regions likely to be highly suited to intercalation behaviour.     

Eight‐ and Twelve‐membered Cyclosilazoxanes: Structural Investigation of Two N‐Pentafluorophenyl‐substituted Si4N3O and Si6N2O4 Rings

The molecular structures of two N‐pentafluorophenylcyclosilazoxanes have been investigated. X‐Ray crystal structure determinations of (C₆F₅)₃Me₈Si₄N₃O ( 2 ) and (C₆F₅)₂Me₁₂Si₆N₂O₄ ( 3 ) revealed the first structurally authenticated examples of eight‐membered Si₄N₃O and twelve‐membered Si₆N₂O₄ ring systems.     

Synthesis and Crystal Structure of Di-n-butyltin（Ⅳ） Complex with 2-Oxo-propionic Acid （4-Pyridinecarbonyl） Hydrazone

The novel complex di‐n‐butyltin(IV) 2‐oxo‐propionic acid (4‐pyridinecarbonyl) hydrazone, (n‐C₄H₉)₂Sn‐[O₂CC(CH₃)=N‐N=C(‐O)C₅N‐4] (H₂O) has been synthesized and its structure has been determined by X‐ray diffraction analysis. The complex crystallizes in orthorhombic system with space group Pca2₁. Crystal data: a=2.7540(9) nm, b=0.9676(3) nm, c= 1.5750(5) nm, V=4.197(2) nm³, D_c= 1.444 g/cm³, Z=8. μ= 1.241 mm^?1. F(000)= 1856, R₁=0.0462 and wR₂=0.1001. In the crystals of the title complex, the tin atom is in six‐coordination with a distorted octahedral geometry, three oxygen atoms [O(1), O(3) and O(4)] and one nitrogen atom N(1) forming the equatorial plane and C(10)‐Sn(1)‐C(14) being the axis. Two molecules form a dimer with weak interactions of Sn‐O bonding and hydrogen bonds.     

Syntheses and crystal structures of Dimolybdenum complexes containing P2 and functionalized Cyclopentadienyl ligands

The dimolybdenum complex [(η⁵-RC₅H₄)₂Mo₂(CO)₆] (1, R = CH₃CO; II, R = CH₃O₂C) reacts with an equimolar amount of white phosphorus P₄ to yield the corresponding dimolybdenum complex containing the P₂ ligand [(η⁵-RC₅H₄)₂Mo₂(CO)₄(μ,η²-P₂)] (1, R = CH₃CO; 2, R = CH₃O₂C) in moderate yield. The two new compounds have been characterized by elemental analyses, ¹H?NMR, ¹³C?NMR, ³¹ P?NMR and IR spectroscopies and their crystal structures have been determined by X-ray diffraction methods.     

Preparation,antitumor activity in mice,pharmacokinetics and tissue distribution in rats of di‐n‐butyl‐di‐(4‐chlorobenzohydroxamato)tin(IV) liposome

Di‐n‐butyl‐di‐(4‐chlorobenzohydroxamato)tin(IV) (DBDCT) is an antitumor compound with high activity and relatively low bioavailability. In order to improve the pharmacokinetic characteristics and raise its therapeutic index, a liposome of DBDCT (DBDCT‐L) was prepared for the first time. A study of the pharmacokinetics and tissue distribution after intravenous administration of DBDCT‐L compared with free DBDCT to rats was investigated. DBDCT‐L showed a slower clearance, increased half‐time and a larger AUC value than those of free DBDCT, which demonstrated that DBDCT‐L could significantly alter the tissue distribution pattern of DBDCT in rats. The highest concentration distribution for DBDCT‐L was detected in liver, which may be associated with the enhanced antitumor activity in vivo against hepatocellular carcinoma H₂₂ and possible target release of the compound. Acute toxicity assay showed that the LD₅₀ value of DBDCT‐L was higher than that of free DBDCT. Further in vivo antitumor test showed that DBDCT‐L displayed higher antitumor activity against the hepatocellular carcinoma H₂₂ than free DBDCT, indicating that the liposome could prolong the action time of DBDCT in the system circulation, change its distribution in rats, reduce acute toxicity and finally increase antitumor activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Organtin complexes of 2,5‐dithiobiurea (H2dtbu): The crystal structures of (Ph3Sn)2(dtbu) and [(n‐Bu)2SnCl]2(dtbu)

A series of organotin(IV) complexes of two types, [R₃Sn]₂(dtbu) (R = PhCH₂ 1 , Ph 2 , n‐Bu 3 , H₂dtbu = 2,5‐dithiobiurea), [R₂SnCl]₂(dtbu) (R = PhCH₂ 4 , Ph 5 , n‐Bu 6 ) have been synthesized and characterized by elemental analysis, IR, and NMR (¹H, ¹¹⁹Sn) spectroscopy. The structures of 2 and 6 have been determined by X‐ray crystallography. Crystal structures show that both complexes 2 and 6 are the symmetric dinuclear unit. Interestingly, supramolecular structures show that complex 2 has formed a linear chain through N H⋅⋅⋅S hydrogen bonding and 6 has formed a two‐dimensional network in perfect bc plane connected through N H⋅⋅⋅Cl hydrogen bonding and nonbonded S⋅⋅⋅S interactions. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:435–442, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20456     

Synthesis and nonlinear optical properties of polyester containing 4‐di‐(2′‐hydroxyethoxy)‐4‐diphenyl‐hydrazonomethyl chromophore

The nonlinear optical property of new polyester has been studied via second harmonic generation (SHG). The values of electro‐optic coefficients, d₃₃ and d₃₁, of the poled polymer film were 3.15 × 10 ^?7 and 1.5 × 10^?7 esu, respectively. Thermal behavior of this polyester was studied through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). 4‐di‐(2′‐hydroxyethoxy)‐4‐diphenyl‐hydrazonomethyl was synthesized from the reaction of 3,4‐dihydroxy‐4‐diphenyl‐hydrazonomethyl with 2–chloro–1‐ethanol in a 1:2 mole ratio and subsequently reacted with terephthaloyl chloride (TPC) in the presence of pyridine, as catalyst, to produce the new nonlinear polyester. The chemical structures of the resulting monomers and polymer were characterized by CHN analysis, ¹H‐NMR, FT‐IR, and UV–Vis spectroscopy. Copyright © 2009 John Wiley & Sons, Ltd.     

Hydrothermal syntheses and crystal structures of two organic–inorganic hybrid molybdovanadates based on [V2Mo6(OH)2O24]4− and [VMo12O40]3− polyoxoanions

Two new organic–inorganic hybrid cobalt-molybdovanadates [Co(phen)₃]H₂[H₂V₂Mo₆O₂₆] · 7H₂O (1) and [Co(2,2′-bipy)₃][Na(H₂O)₇][VMo₁₂O₄₀] (2) have been hydrothermally synthesized and structurally characterized by elemental analyses, IR, UV, XPS spectroscopy, thermogravimetric (TG) analyses, and X-ray single crystal diffraction. The molecular structure of 1 consists of a [V₂Mo₆(OH)₂O₂₄]^4? polyoxoanion, a [Co(phen)₃]²⁺, two H⁺ and seven lattice water molecules. The structure of [V₂Mo₆(OH)₂O₂₄]^4? consists of six MoO₆ octahedra and two VO₄ tetrahedra; six MoO₆ octahedra are linked by edge-sharing oxygens forming a {Mo₆} ring, and two VO₄ tetrahedra cap opposite sides of the {Mo₆} ring. The molecular structural unit of 2 is constructed from a typical Keggin-type [VMo₁₂O₄₀]^3? polyoxoanion and a [Co(2,2′-bipy)₃]²⁺ cation and a Na⁺ countercation; Co²⁺ is coordinated by six nitrogens from three 2,2′-bipyridines forming a distorted octahedron.     

Novel five‐membered ring formation by oxidative photocyclization of 4‐(2‐arylvinyl)benzo[a]quinolizinium salts

Oxidative photocyclization of 4‐(2‐arylvinyl)benzo[a]quinolizinium salts ( 6 ) gave five‐ or six‐mem‐bered rings depending on the aryl substituent. The olefins 6a and 6b with a phenyl or naphthyl substituent resulted in a normal six‐membered ring formation to afford 6a‐azoniapicene and 6a‐azoniabenzo[b]picene salts ( 7 and 8 ), respectively. In contrast, the photo‐reaction of pyridyl substituted derivative 6c resulted in novel five‐membered ring formation to yield 3b‐azonia‐5‐(2‐pyridyl)acephenanthrylene salt ( 10 ).     

Synthesis and characterization of organotin complexes with dithiocarbamates and crystal structures of (4‐NCC6H4CH2)2Sn(S2CNEt2)2 and (2‐ClC6H4CH2)2 Sn(Cl)S2CNBz2

Ten organotin derivatives with dithiocarbamates of the formulae (4‐NCC₆H₄CH₂)₂Sn(S₂CNEt₂)₂ (1), (4‐NCC₆H₄CH₂)₂Sn(S₂CNBz₂)₂ (2), (4‐NCC₆H₄CH₂)₂Sn[S₂CN(CH₂CH₂)₂NCH₃]₂ (3), (2‐ClC₆H₄CH₂)₂ Sn(S₂CNEt₂)₂ (4), (2‐ClC₆H₄CH₂)₂Sn(S₂CNBz₂)₂ (5), (4‐NCC₆H₄CH₂)₂Sn(Cl)S₂CNEt₂ (6), (4‐NCC₆H₄CH₂)₂Sn(Cl)S₂CNBz₂ (7), (4‐NCC₆H₄CH₂)₂Sn(Cl)S₂CN(CH₂CH₂)₂NCH₃ (8), (2‐ClC₆H₄CH₂)₂ Sn(Cl)S₂CNEt₂ (9) and (2‐ClC₆H₄CH₂)₂Sn(Cl)S₂CNBz₂ (10) have been prepared. All complexes were characterized by elemental analyses, IR and NMR. The crystal structures of complexes 1 and 10 were determined by X‐ray single crystal diffraction. For complex 1, the central tin atom exists in a skew‐trapezoidal planar geometry defined by two asymmetrically coordinated dithiocarbamate ligands and two 4‐cyanobenzyl groups. In addition, because of the presence of close intermolecular non‐bonded contacts, complex 1 is a weakly‐bridged dimer. In complex 10, the central tin atom is rendered pentacoordinated in a distorted trigonal bipyramidal configuration by coordinating with S atoms derived from the dithiocarbamate ligand. In vitro assays for cytotoxicity against five human tumor cell lines (MCF‐7, EVSA‐T, WiDr, IGROV and M226) furnished the significant toxicities of the title complexes. Copyright © 2006 John Wiley & Sons, Ltd.     

Syntheses and Crystal Structures of Two New Open‐Framework Tin(II) Phosphates: Sn5O2(PO4)2 and Sn4O(PO4)2

Two new three‐dimensional neutral open‐framework tin(II) phosphates, Sn₅O₂(PO₄)₂ and Sn₄O(PO₄)₂, were synthesized under hydrothermal conditions with different ratio of tin(II) oxalate, phosphoric acid and 4,4′‐diaminodiphenylmethane. Their crystal structures have been solved by single‐crystal X‐ray diffraction methods. Sn₅O₂(PO₄)₂ crystallizes in the space group and contains six‐membered ring and twelve‐membered ring channels running parallel to the b axis. Sn₄O(PO₄)₂ crystallizes in the space group P2₁/n and contains intersecting eight‐membered ring channels. These two compounds have rare trigonal‐planar Sn₃O.     

The first crystal structures of six‐ and seven‐membered tellurium‐ and nitrogen‐containing (Te—N) heterocycles: 2H‐1,4‐benzotellurazin‐3(4H)‐one and 2,3‐dihydro‐1,5‐benzotellurazepin‐4(5H)‐one

There is a paucity of data concerning the structures of six‐ and seven‐membered tellurium‐ and nitrogen‐containing (Te—N) heterocycles. The title compounds, C₈H₇NOTe, (I), and C₉H₉NOTe, (II), represent the first structurally characterized members of their respective classes. Both crystallize with two independent molecules in the asymmetric unit. When compared to their sulfur analogs, they exhibit slightly greater deviations from planarity to accommodate the larger chalcogenide atom, with (II) adopting a pronounced twist‐boat conformation. The C—Te—C angles of 85.49 (15) and 85.89 (15)° for the two independent molecules of (I) were found to be somewhat smaller than those of 97.4 (2) and 97.77 (19)° for the two independent molecules of (II). The C—Te bond lengths [2.109 (4)–2.158 (5) Å] are in good agreement with those predicted by the covalent radii. Intermolecular N—H...O hydrogen bonding in (I) forms centrosymmetric R₂²(8) dimers, while that in (II) forms chains. In addition, intermolecular Te...O contacts [3.159 (3)–3.200 (3) Å] exist in (I).     

New lacunar-type and pendant groups containing derivatives of β-unsubstituted dibenzotetraaza[14]annulenes—syntheses and crystal structures

Three new lacunar-type derivatives of β-unsubstituted dibenzotetraaza[14]annulene have been synthesized along with a range of their open-chain pendant group containing counterparts. The crystal structures of two representative products have been determined and the noncovalent interactions explored. A number of C-H?π and π?π interactions involving aliphatic chains and aromatic regions of the macrocycle have been evidenced. The relative ease and high yield of lacunization are suggested to be largely due to self-assembly processes, driven by favorable noncovalent interactions between reacting units.