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The title molecule, [Sn(C8H3F6)4], lies on a twofold rotation axis with the SnIV ion in a distorted tetrahedral coordination environment. Both –CF3 groups attached to one of the unique benzene rings are disordered over two sets of sites, with the ratios of refined occupancies being 0.719 (14):0.281 (14) and 0.63 (5):0.37 (5).

The threat of antibiotic-resistant, biofilm-forming bacteria necessitates a preventative approach to combat the proliferation of robust, pathogenic strains on "high touch surfaces" in the food packaging, biomedical, and healthcare industries. The development of both biocide-releasing and tethered, immobilized biocide surface coatings has risen to meet this demand. While these surface coatings have demonstrated excellent antimicrobial efficacy, there are few examples of antimicrobial surfaces with long-term durability and performance. To this end, UV-curable phosphoniums bearing benzophenone anchors with either an alkyl, aryl, or fluoroalkyl group were synthesized and their efficacy as thermally stable antimicrobial additives in extruded plastics or as surface attached coatings probed. The surface topology and characteristics of these materials were studied to gain insight into the mechanism of their antimicrobial activity. Efficacy against both Gram negative and Gram positive bacteria as either a coating or additive showed compete reductions of the initial bacterial load. Crucially, the materials maintained the ability to kill biofilm-forming bacteria even after being subject to several cycles of abrasion.

Contact-active ammonium and phosphonium antimicrobial polymeric coatings grafted to plastic surfaces by UV treatment are described. Robust, antimicrobial styrenic polymeric scaffolds copolymerized with a low loading of UV-curable benzophenone were prepared by nitroxide-mediated polymerization (NMP). Similar reversible addition-fragmentation chain-transfer (RAFT)-controlled radical polymerizations were attempted for comparison. These random styrenics were further functionalized into partially quaternarized water-soluble cationic polymers. UV-cured polymeric thin film coatings possessing cationic groups with

In this paper we outline two major findings. The first is that we describe how designer hypercoordinate stannanes can be made from simple substitutions, and by extension, designer tin polymers, at least partially, using these methods. The second is that using advanced DFT methods, 119Sn NMR frequencies have been accurately calculated for select hypercoordinate tin compounds. This accuracy provides a means for further investigation of an important bonding interaction in the solution phase, and is of significant interest to small molecule tin chemists.

Background: The COVID-19 pandemic has had an unprecedented impact on global health and the world's economies. Proliferation of virulent and deadly SARS-CoV-2 variants require effective transmission mitigation strategies. Under reasonable environmental conditions, culturable and infectious SARS-CoV-2 can survive on contaminated fomites from hours to months. In the present study we evaluated a surface-anchored polymeric quaternary ammonium antimicrobial to help reduce fomite transmission of SARS-CoV-2 from contaminated surfaces. Methods: Two studies were performed on antimicrobial pre-treated metal disks in March 2020 by two independent Biosafety Level 3 (BSL-3) equipped laboratories in April 2020. These facilities were in Belgium (the Rega Medical Research Institute) and Australia (the Peter Doherty Institute) and independently applied quantitative carrier-based methodologies using the authentic SARS-CoV-2 isolates (hCoV-19/Australia/VIC01/2020, hCoV-19/Belgium/GHB-03021/2020). Results: Residual dry tests were independently conducted at both facilities and demonstrated sustained virion destruction (108.23 TCID50/carrier GHB-03021 isolate, and 103.66 TCID50/carrier VIC01 isolate) 1 hour (drying) + 10 minutes after inoculation. Reductions are further supported by degradation of RNA on antimicrobial-treated surfaces using qRT-PCR. Conclusions: Using a polymeric quaternary ammonium antimicrobial (EPA/PMRA registered) the results independently support a sustained antiviral effect via SARS-CoV-2 virion destruction and viral RNA degradation. This indicates that silane-anchored quaternary ammonium compound (SiQAC-18) treated surfaces could play an important role in mitigating the communicability and fomite transmission of SARS-CoV-2.

With the risks associated with healthcare-associated infections and the rise of antibiotic resistant microorganisms, there is an important need to control the proliferation of these factors in hospitals, retirement homes and other institutions. This work explores the development and application of a novel class of sulfonamide-based quaternary ammonium antimicrobial coatings, anchored to commercially and clinically relevant material surfaces. Synthesized in high yields (60–97%), benzophenone-anchored antimicrobials were spray-coated and UV grafted onto plastic surfaces, while silane-anchored variants were adhered to select textiles via dip-coating. Surface modified samples were characterised by advancing contact angle, anionic dye staining, X-ray photoelectron spectroscopy and atomic force microscopy. After verifying coating quality through the above characterization methods, microbiological testing was performed on batch samples in conditions that simulate the natural inoculation of surfaces and objects (solid/air) and water containers (solid/liquid). Using the previously established Large Drop Inoculum (LDI) protocol at solid/air interfaces, all treated samples showed a full reduction (105–107 CFU) of viable Arthrobacter sp., S. aureus, and E. coli after 3 h of contact time. Additional testing of the walls of plastic LDPE vials treated with a UV-cured sulfonamide antimicrobial at a solid/liquid interface using the newly developed Large Reservoir Inoculum (LRI) protocol under static conditions revealed a complete kill (>106 reduction) of Gram-positive Arthrobacter sp., and a partial kill (>104 reduction) of Gram-negative E. coli within 24–48 h of contact.

Diorganotin dihalides act as cocatalysts for site-selective and stereoselective couplings of diol-containing carbohydrates with electron-deficient alkenes in the presence of an Ir(III) photoredox catalyst and quinuclidine, a hydrogen atom transfer mediator. Quantum-chemical calculations support a proposed mechanism involving the formation of a cyclic stannylene acetal intermediate that shows enhanced reactivity toward hydrogen atom abstraction by the quinuclidinium radical cation. Addition of the carbon-centered radical to the alkene partner results in C-alkylation of the carbohydrate substrate.

The Large Droplet Inoculation (LDI) protocol for testing antimicrobial coatings and treatments is simple, reproducible, and closely mimics real-world conditions at solid/air interfaces. This is an advancement of the current ISO 22196/JIS Z 2801 standard method, as it provides greater ease-of-use and more closely resembles the contamination of common surfaces. The protocol involves inoculating 100 µL droplets containing ~107 microbial cells of a test microorganism onto sets of antimicrobial-treated and untreated control sample material. The sets are protected from dust accumulation and allowed to air dry, which causes all cells within each droplet to encounter the sample surface. The surviving cells are then collected by vortexing in a collection liquid and enumerating to evaluate differences in survival on the antimicrobial-treated and untreated control samples. Overall, the LDI protocol requires 10 hours of basic microbiology over one week and provides a simple means of assessing the efficacy of various antimicrobial coatings and treatments.

Water dispersible polyester resins derived from dimethyl terephthalate, dimethyl 5-sulfoisophthalate sodium salt, 1,2-propane diol and diethylene glycol were prepared. ADesign of Experiment (DOE) was explored by varying the concentration of the ionic 5-sulfo-isophthalate sodium salt and diethylene glycol at various molecular weights and found tocorrelate with particle size dispersion of the sulfonated resins in water. An empirical model for the resin glass transition was also obtained through experimental design.

A series of H2O and/or EtOH soluble, self-assembling quaternary ammonium salts containing a dansyl (DNS) fluorescent moiety suitable for attachment to both porous ([DNS–NH–(CH2)3–NMe2–R+][X−] (2; R = –Si(OMe)3, X− = Cl−) and non-porous (3a; R = –PO(OEt)2, 3b; –PO(Oi-Pr)2, 3c; –(PO(OH)2, X− = Br−), 4; ([DNS–NH–(CH2)3–NMe2–(CH2)3–NH(CH2PO(OEt)2)2+][Br−], 5; R = –((CH2)3SCOCH3, X− = Cl−), 6a; (R = –(CH2)nO(C6H4)CO(C6H5), n = 3, X− = Br−, 6b; n = 3, X− = Cl−, 6c; n = 3, X− = I−, 6d; n = 4, X− = Br−, 6e; n = 4, X− = I−, 6f; n = 6, X− = Br−, 6g; n = 6, X− = Cl−, 6h; n = 6, X− = I−), 7; (R = –CH2–CHCH2, X− = Br−) surfaces were prepared from the precursor dansyl amine (1; DNS–NH–(CH2)3–NMe2). Compounds 1–7 were characterized by NMR (1H, 13C, 29Si (2), 31P (3a–c, 4)) spectroscopy, HRMS, UV-Vis and fluorescence spectroscopy. Additional characterization of compounds 1 and 7 were carried out by X-ray structure determinations. Physical attachment of compound 2 to cotton surfaces after immersion in solutions containing fluorescent dyes was verified by exposure to UV light and by complexation with bromo-phenol blue that rendered the surfaces visibly blue in colour. Phosphorus containing dansyl fluorescent dye, 3c, was attached to a stainless steel surface by exposure to an aqueous solution containing this dye, resulting in the formation of a self-assembled fluorescent monolayer. UV cure of plastic surfaces (polypropylene, silicon medical tubing) coated with compound 6a resulted in the covalent attachment of the dyes.

The synthesis and solid-state molecular structures of two dichlorido(aryl)(alkyl) tin compounds, 5 and 8, both key intermediates to tunable polystannane architectures, are reported. The materials were further investigated by single-crystal XRD and a DFT analysis of their preferential "open and closed" geometries. Conversion of said compounds to their dihydride analogues was undertaken, followed by their application as monomers for polystannane polymer synthesis. The properties of two asymmetrical polystannanes prepared by transition-metal-catalyzed dehydropolymerization of dihydrido(aryl)alkylstannanes (6 and 9) were investigated. The first product was the structurally simple, modest molecular weight, semi-crystalline light- and moisture-stable polystannane 10 with NMR (119 Sn) evidence of prominent Sn←O hypercoordination along the polymer backbone. The second was the lower molecular weight, tosylated four-coordinate polystannane 11 with no evidence of hypercoordination. Differential scanning calorimetry (DSC) of polymer 10 revealed a reversible semi-crystalline nature, whereas an amorphous character was detected for polymer 11. Polystannane 10 was also found to be exceptionally stable to both moisture and light (>6 months) and a promising candidate for the design of readily modified (i.e., tunable) polystannane materials.

The synthesis and characterization of polystannanes with "push" or "pull" moieties attached to the tin backbone are described. Precursor tetra aryl- (1, 2) stannanes were converted to mono- (3) and dichloro- (4, 5) stannanes by either sequential chlorination or by redistribution reactions with SnCl4. Compounds 4 and 5 were transformed to polymerisable tin dihydride monomers 6 and 7 using a large excess (10×) of NaBH4. Homopolymer 8 with electron donating aryl substituents (p-MeOC6H4-) was synthesized by dehydrogenative polymerization using Wilkinson's catalyst. Attempts to prepare the homopolymer 9 with electron withdrawing aryl substituents (p-CF3C6H4-) from the dehydrocoupling of 7 using similar conditions led only to the formation of low molecular weight oligomeric species. Two alternating polymers, 10 and 11, were synthesized by condensation polymerization of (n-Bu)2Sn(NEt2)2 with monomers 6 or 7. The first was a "push-push" alternating polymer, 10, comprised of a repeating unit consisting of two different electron donating groups (p-MeOC6H4-, n-Bu) at neighboring tin centres. The second was a "push-pull" alternating polymer, 11, bearing both an electron donating group (n-Bu) and a strongly electron withdrawing substituent (p-CF3C6H4-) at neighboring tin atoms. All small molecule stannanes and tin-containing polymers were characterized by NMR (1H, 13C, 119Sn, and where required 19F) spectroscopy, MS or EA. The absolute molecular weights of tin polymers (8, 10, 11) were determined by triple detection GPC and in the range of 1.07 × 104 to 1.95 × 104 Da. Rapid photodegradation of polymers was observed by UV-Vis spectroscopy, with a slower degradation observed for the "push-pull" polymer, 11, compared to the "push-push" polymer, 10.

A series of cyclic thionylphosphazenes were prepared and density functional theory (DFT) calculations initiated to gain insight into their susceptibility to ambient ring-opening polymerization with Lewis acid catalysts (GaCl3, AlCl3). DFT analyses determined that PBE1PBE-GD3BJ provided the optimal calculated structures for 1, 5, 5’ and 8. The gauge-independent atomic orbital (GIAO) method (M05-2X-GD3//PBE1PBE-GD3BJ) provided a good approximation for the 31P NMR resonances. Energy calculations indicate that thionylphosphazene phosphorus substitution promotes heterolytic cleavage of the thionyl S–Cl bond, as does adduct formation with GaCl3 or AlCl3, suggesting that 4 has potential for GaCl3-catalyzed ROP reactions at ambient temperatures. The generation of thionylphosphazene cation from 1 with catalytic quantities of Lewis acids (10:1 GaCl3, AlCl3) initiates the ambient temperature ROP to poly(thionylphosphazene) (2) in a minimum amount of solvent. Polymerization/depolymerization studies of 1 and 2 in solution was found to be fully reversible in the presence of GaCl3.

Polystannanes with azobenzene moieties designed to protect the Sn-Sn backbone from light- and moisture-induced degradation is described. The azo-stannyl precursor 3 (70%) is converted in good yields (88-91%) to the mono- (4), and dichloro- (5) stannanes, by sequential chlorination, followed by further reduction of 5 to the dihydride (6) using NaBH4 (78%). All stannanes were characterised by NMR (1H, 13C, 119Sn) spectroscopy and HRMS; in addition, 3, 4 and 5 were structurally elucidated via X-ray diffraction analysis. Metal-free dehydrocoupling of 6 at RT leads exclusively to homopolymer (7-i) displaying an initial solution 119Sn NMR signal ( = -196 ppm) that migrates to -235 ppm after 10 days (7-f). In contrast, metal-catalyzed dehydrocoupling of 6 in toluene at RT leads directly 7-f. Random co-polymers formed from 6 and (n-Bu)2SnH2 at 4:1 (8a) and 1:1 (8b) ratios were compared to the alternating polystannane (9) prepared by the reaction of 6 with (n-Bu)2Sn(NEt2)2. DFT calculations of 3-6 indicate that hypercoordination at Sn is influenced by substituents and by solvation. Homopolymer 7 was found to have unprecedented moisture and light stability in the solid state for > 6 months.

The synthesis and full characterisation, including in one case via single crystal X-ray diffraction, of two novel bio-derived aromatic monomers are reported. These materials, incorporating a Eugenol or Vanillin molecular skeleton are modified to incorporate diol chains obtained from reaction with glycerine carbonate. They are further characterised by the presence of other groups (e.g., allyl) which are also capable of engendering polymerisation. Facile heat induced self-polymerization is noted in one of the new monomers. The compounds are further tested in block co-polymer synthesis and found to form blocks with simple co-monomers such as succinic acid.

A library of precursor and functionally active quaternary ammonium cations (QACs) for use as corrosion resistant and or antimicrobial coatings, or alternatively as polymer modifiers, is described. High yielding and improved routes to a series of functionally terminated allyl ([(CH2=CH-CH2)m-N+(Me)n-C18H37][X−], 1: m=1, n=2, X−=Br−, 3: m=2, n=1, X−=I−, 4: m=3, n=0, X−=Br−) vinyl ([CH2=CHCH2CH2-N+Me2-C18H37][Br−] 5), hydroxy ([HO-(CH2)m-N+Me2-C18H37][Br−], 6: m=3, 7: m=4), haloalkyl ([X1-(CH2)3-N+Me2-C18H37][X−] 8: X1=Br, X=Br−, 9: X1=Cl, X=I−), dimethoxyphenethyl ([(MeO)2C6H3(CH2)2-N+Me2-C18H37][Br−], 11), acetamido ([H3C(O)NH-(CH2)3-N+Me2-C18H37][Cl−], 12) cyano ([N≡C–CH2-N+Me2-C18H37][Cl−], 13), organocarbonylamino ([R-C(O)2NH-(CH2)3-N+Me2-C18H37][Br−], 14: R=t-Bu-, 15: R=PhCH2-), phthalimido ([PhthN-(CH2)3-N+Me2-C18H37][Br−], 16), amino ([H2N-(CH2)3-N+Me2-C18H37][Br−] 17), acetylthio ([HC(O)S-(CH2)3-N+Me2-C18H37][Cl−], 18), thiol ([HS-(CH2)3-N+Me2-C18H37][Cl−] 19), disulfa ([-S-(CH2)2-N+Me2-C18H37]2[Br−]2, 20) C18 QACs prepared by thermal and or microwave driven Menshutkin reactions are detailed. All new compounds were characterized by NMR spectroscopy, HRMS spectrometry and in the case of 1 and 6 by X-ray crystallography.

This review surveys recent developments in the field of pentacoordinated group 14 (i.e., Si, Ge, Sn, Pb) small molecules, and more specifically Sn compounds, containing ligands with datively linked electron donating atoms such as N, P, O and S. It describes the syntheses of these compounds by a variety of techniques as well as investigations into their unique structures and electronic properties.

Tetraorganotin tin(IV) compounds containing a flexible or rigid (4: Ph3Sn-CH2-C6H4-R, 7: Ph3SnC6H4-R, R = 2-oxazolinyl) chelating oxazoline functionality were prepared in good yields by the reaction of lithiated oxazolines and Ph3SnCl. Reaction of 7 with excess HCl resulted in the isolation of the tin monochlorido compound, 9 (ClSn[Ph2]C6H4-R). Conversion of the triphenylstannanes 7 and 4 into their corresponding dibromido species was successfully achieved from the reaction with Br2 to yield 10 (Br2Sn[Ph]C6H4-R) and 11 (Br2Sn[Ph]-CH2-C6H4-R), respectively. X-ray crystallography of 4, 7, 9, 10, and 11 reveal that all structures adopt a distorted trigonal bipyramidal geometry around Sn in the solid state. Compound 4, with an additional methylene spacer group, displays a comparatively long Sn&ndash, N bond distance compared to the dibromido tin species, 11. Several DFT methods were compared for accuracy in predicting the solid-state geometries of compounds 4, 7, 9&ndash, 11. Compounds 10 and 11 were further converted into the corresponding dihydrides (12: H2Sn[Ph]C6H4-R, 13: H2Sn[Ph]-CH2-C6H4-R), via Br&ndash, H exchange, in high yield by reaction with NaBH4. Polymerization of 12 or 13 with a late transition metal catalyst produced a low molecular weight polystannane (14: &ndash, [Sn[Ph]C6H4-R]n&ndash, Mw = 10,100 Da) and oligostannane (15: &ndash, [Sn[Ph]-CH2-C6H4-R]n&ndash, Mw = 3200 Da), respectively.

A series of model linear tristannanes [((1R)3Sn)2(2R)2Sn (1: 1R = 2R = n-Bu, 2: 1R = Ph, 2R = n-Bu, 3: 1R = Me, 2R = n-Bu, 4: 1R = n-Bu, 2R = Ph, 5: 1R = Me, 2R = Ph, 6: 1R = n-Bu, 2R = Me, 7: 1R = Ph, 2R = Me)] were prepared by condensation reactions of one equivalent of a dialkyl or diaryl tin diamide or dihydride and two equivalents of a trialkyl or triaryl tin hydride or amide respectively, and characterized by NMR (1H, 13C, 119Sn) and UV–Vis spectroscopy, and elemental analysis. An LSDA/SDD level of DFT and TD-DFT for trimers 1–7 predicts significant structural differences as a function and nature of the substituents bound to tin and calculated electronic transitions for these compounds in fair relative agreement with experimental results. Calculated electronic spectra obtained from equivalent DFT studies of the sequentially lengthened oligomers Ph3Sn[t-Bu2Sn]nSnPh3 (8–11 where n = 1–4) previously prepared by Drager are in good agreement with the reported experimental UV–Visible spectroscopic and X-ray diffraction data which show a red shift of the σ–σ* absorption transition (λmax) and bond lengthening and bond angle widening of the central tin atoms as the oligostannane is extended. TD-DFT studies of the alkoxy terminated di(n-butyl) oligostannanes 12a–m (CH3CH2OCH2CH2[Sn(n-Bu)2]nCH2CH2OCH2CH3); n = 3–15) indicate lower limiting energy gaps as the polymer chain size is increased. The calculated data deviates significantly from results found experimentally by Sita and suggests that even smaller energy gaps are possible if the polymer (13) resides in an all trans configuration. TD-DFT studies at the LSDA/SDD level were also carried out on a model polystannane 16 (H[SnH2]nH, n = 1–40) to investigate the impact of Sn catenation on the intrinsic band gap of the material and compared to both the Si and Ge analogues 14 and 15 (H[MH2]nH, M = Si, Ge: n = 1–40). The modelling of the polymetallanes reveals the expected limiting energy gap of the σ–σ* transition in a trans-planar configuration with Sn (2.681 eV)

A new condensation polymerization route leading to alternating polystannanes is presented. The stoichiometric reaction of tin dihydrides and tin diamides in diethyl ether or toluene under mild reaction conditions afforded three new moderate molecular weight alternating polystannanes, -[Ph2Sn-alt-Sn(n-Bu)2]n-, -[Ph2Sn-alt-SnMe2]n-, -[Me2Sn-alt-Sn(n-Bu)2]n-, in addition to a known homopolymer, -[(n-Bu)2]n-.

A series of aryloxy organotin compounds Ph3Sn(CH2)3OC6H4R (5: R = H; 6: R = Ph; 7: R = OCH3, 8: R = CF3), Ph2ClSn(CH2)3OC6H4R (9: R = H; 10: R = Ph) and PhCl2Sn(CH2)3OC6H4R (12: R = H; 13: R = Ph) have been synthesized and characterised by NMR (1H, 13C, 119Sn) spectroscopy. X-ray structure determinations of 9, 10, 12 and 13 reveal a distorted trigonal bipyramidal geometry at Sn with Cl trans to the datively bonded O whereas 8 possesses tetrahedral geometry and a Sn⋯O dative interaction is absent. Triorganotin hydrides Ph2HSn(CH2)3OC6H4R (14: R = H; 15: R = Ph) and diorganotin dihydrides PhH2Sn(CH2)3OC6H4R (16: R = H; 17: R = Ph) were prepared by reduction of the corresponding dihalides with LiAlH4. Catalytic dehydrocoupling of dihydrides 16 or 17 with a late transition metal catalyst afforded asymmetrical hypercoordinated polystannanes [PhSn(CH2)3OC6H4R]n (18: R = H; 19: R = Ph) with relatively high molecular weights (Mw = 1.3 × 104 – 2.5 × 105 Da) and narrow polydispersities (PDI's = 1.3–3.3). NMR and UV–Vis spectroscopy studies indicate that the new polymers display dramatically improved light stability, but remain sensitive to moisture.

A series of UV active benzophenone ([C6H5COC6H4-O-(CH2)n-N+Me2R][X–]; 4, R = C12H25, n = 3, X– = Br–; 5a–c, R = C18H37, n = 3, X– = Cl–, Br–, I–; 6a–c, R = C18H37, n = 4, X– = Cl–, Br–, I–; 7a–c, R = C18H37, n = 6, X– = Cl–, Br–, I–) terminated C12 and C18 quaternary ammonium salts (QACs) were prepared by thermal or microwave-driven Menshutkin protocols of the appropriate benzophenone alkyl halide (1a–c, 2a–c, 3a–c) with the corresponding dodecyl- or octadecyl N,N-dimethylamine. All new compounds were characterized by NMR spectroscopy, HRMS spectrometry, and, in one instance (4), by single-crystal X-ray crystallography. Representative C12 and C18 benzophenone QACs were formulated into 1% (w/v) water or water/ethanol-based aerosol spray coatings and then UV-cured onto plastic substrates (polypropylene, polyethylene, polystyrene, polyvinyl chloride, and polyether ether ketone) with exposure to low to moderate doses of UV (20–30 J cm–2). Confirmation as to the presence of the coatings was detected by advanci...

A new patent pending technique is proposed in this study to improve the mechanical and biological performance of ultra high molecular weight polyethylene (UHMWPE), i.e., to uniformly coat nylon onto the UHMWPE fiber (Firouzi et al., 2012). Mechanical tests were performed on neat and new nylon coated UHMWPE fibers to examine the tensile strength and creep resistance of the samples at different temperatures. Cytotoxicity and osteolysis induced by wear debris of the materials were investigated using (MTT) assay, and RT-PCR for tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6) osteolysis markers. Mechanical test results showed substantial improvement in maximum creep time, maximum breaking force, and toughness values of Nylon 6,6 and Nylon 6,12 coated UHMWPE fibers between average 15% and 60% at 25, 50, and 70°C. Furthermore, cytotoxicity studies have demonstrated significant improvement in cell viability using the nylon coated UHMWPE over the neat one (72.4% vs 54.8%) for 48h and (80.7 vs 5%) for 72h (P

Theoretical calculations illustrate that organometallic macromolecules with piano stool coordination repeating units (Fe-acyl complex) adopt linear chain configuration with a P-Fe-C backbone surrounded by aromatic groups. The macromolecules show molecular weight-dependent and temperature stimulated solution behaviour in DMSO.

A series of 2-methoxymethyl tetraorganotins [2-(MeOCH2)C6H4]SnR3 (21: R = Ph; 22: R = n-Bu; 23: R = Me), diorganotin chlorides [2-(MeOCH2)C6H4]R2SnCl (24: R = Ph; 25a, 25b: R = n-Bu), monoorganotin dichlorides [2-(MeOCH2)C6H4]RSnCl2 (26: R = Ph; 27: R = n-Bu; 28: R = Me) and the tin trichloride [2-(MeOCH2)C6H4]SnCl3 (29) were successfully prepared from the reaction of the organolithium, [2-(MeOCH2)C6H4]Li, and the appropriate chlorostannane. Similarly, a series of dimethylamino stannanes including the tetraorganotin [2-(Me2NCH2)C6H4]SnPh3 (30), the diorganotin halides [2-(Me2NCH2)C6H4]Ph2SnX (34: X = Cl; 35: X = Br), dichlorides [2-(Me2NCH2)C6H4]RSnCl2 (38: R = Ph; 39: R = n-Bu; 40: R = Me) and the tribromide [2-(Me2NCH2)C6H4]SnBr3 (37) were prepared by reaction of the appropriate organochlorostannane and the organolithium [2-(Me2NCH2)C6H4]Li followed by selective halogenations in the case of 34–37. 2-Methoxymethyl and dimethylamino diorganotin dichlorides (27, 28 and 39, 40) were hydrogenated with LiAlH4 to produce new 2-methoxymethyl [2-(MeOCH2)C6H4]RSnH2 (41: R = n-Bu; 42: R = Me) and dimethylamino [2-(Me2NCH2)C6H4]RSnH2 (44: R = n-Bu; 45: R = Me) dihydrides. X-ray structure determination of 30 revealed a nearly tetrahedral stannane, while structural analysis of 24, 29 and 40 display distorted trigonal bipyramidal geometry at Sn with Cl trans to the datively coordinated heteroatom. A selection of DFT methods were assessed for accuracy in predicting the solid-state geometries of the hypercoordinate Sn complexes. Catalytic dehydrocoupling of C,O- (41) and C,N- (44) diorganotin dihydrides was explored using Wilkinson's catalyst at RT leading to the recovery of modest molecular weight polymers (52: Mw = 3.03 × 104 Da, PDI = 1.4, 53: Mw = 3.1 × 104 Da, PDI = 1.86). The new rigid polymers were isolated in moderate (52: 65%) and low yields (53: 18%) and were found to be amorphous by DSC.

A brief overview is presented on recent advances in the application of nickel coordination complexes as mediators of olefin polymerisation; in some cases involving stereo-regular polymer formation where appropriate. Emphasis is also given on recent findings concerning di- and tri-nuclear Ni clusters with details on ethylene, methyl methacrylate or styrene-based monomer polymerisations.

The symmetrical bisferrocene 1,1,14,14-tetra-n-butyl-2,2,13,13,15,15,26,26-octamethyl-1,2,13,14,15,26-hexastanna[3.3]ferrocenophane ([(η5-C5H4)Fe(η5-C5H4SnMe2Sn(n-Bu)2SnMe2)]2, 8) was synthesized in good yield (82%) from the reductive coupling reaction of 1,1′-bis(dimethylstannyl)ferrocene, 6, with one equivalent of di-n-butylbis(diethylamino) stannane, 7a, at 0 °C in diethyl ether solution. Compound 8 is stable to ambient light but decomposes in the presence of moisture or chlorinated solvents. The title compound 8 was characterized by NMR (1H, 13C, 117Sn, 119Sn) spectroscopy, HRMS, and elemental analysis. A statistical model to account for the 117Sn/119Sn coupling patterns, observed in both the 117Sn and 119Sn NMR spectra, was undertaken and is a good fit to experimental data. Investigations by UV–vis spectroscopy display a visible d–d transition at λmax at 455 nm (e = 74 L mol–1 cm–1), while cyclic voltammetry reveals two reversible oxidation events at 0.01 and 0.23 V (relative to the ferrocene/ferroce...

The ambient temperature condensation, to yield low molecular weight poly(methyloxothiazene) (Mw = 1 × 104; PDI = 1.4), can be achieved by the reaction of MeS(O2)NHSiMe3 and SOCl2—this latter reaction being performed in an attempt to isolate ClSMe(O)NSiMe3 (6a). The in situ addition of a Lewis acid initiator (e.g., PCl5) to freshly prepared samples of N-silylsulfonimidoyl chlorides (ClSR(O)NSiMe3, 6a–d, R = Me, Et, Ph, p-C6H4Me) yielded high molecular weight, narrowly dispersed polymers, 5a–d (Mw = 6.7 × 104–3.3 × 106; PDI = 1.2–1.6) of general formula [RS(O)═N]n. These materials have been characterized by GPC, NMR (1H, 13C) spectroscopy, and DSC. UV–vis spectroscopy of CH2Cl2 solutions of 5a–d reveal a high-energy π–π* transition (λmax = 300–350 nm) that tails into the visible. Additionally, theoretical modeling of oligomeric (methyloxothiazenes) at either a semiempirical, Hartree–Fock, or DFT level of theory suggests that these polymers adopt an irregular helical architecture.

A series of strained, silicon-bridged [1]ferrocenophanes with methylated cyclopentadienyl rings, which are prospective monomeric precursors of poly(ferrocenylsilanes) via ring-opening polymerization, has been synthesized and characterized. The dimethylated silicon-bridged [1]ferrocenophanes Fe(η-C5H3Me)2SiMe2 (4) were prepared as a mixture of isomers via the reaction of Fe(η-C5H3MeLi)2·TMEDA (TMEDA = tetramethylethylenediamine) with Me2-SiCl2. The 3,3′-syn isomer 4a was cleanly isolated via low-temperature crystallization. The tetramethylated silicon-bridged [1]ferrocenophane Fe(η-C5Me4)(η-C5H4)SiMe 2 (6) and the octamethylated silicon-bridged [1]ferrocenophane Fe(η-C5Me4)2SiMe2 (8) were prepared via the reaction of FeCl2 with Li2[(C5Me4)(C5H 4)SiMe2] and Li2[(C5Me4)2SiMe2], respectively. X-ray diffraction studies of 4a and 8 revealed that these molecules possess highly strained ring-tilted structures. Comparison with the previously determined structure of Fe(η-C5H4)2-SiMe2 (1) revealed that, with increasing ring methylation, the tilt angle between the planes of the cyclopentadienyl ligands decreases significantly (1, 20.8(5)°; 4a, 18.6(3)°; 8, 16.1(3)°), the angle between the cyclopentadienyl ligand and the ipso cyclopentadienyl carbon-silicon bond increases (1, 37.0(6)°; 4a, 39.1(2)°; 8, 40.3(2)°), and the Fe-Si distance decreases (1, 2.690(3) Å; 4a, 2.6767(8) Å; 8, 2.652(1) Å). Cyclic voltammetric analysis of 1, 4a, 6, and 8 in CH2Cl2 revealed that each ferrocenophane exhibits a reversible, one-electron oxidation. Analysis of 1 and 8 by 57Fe Mössbauer spectroscopy in conjunction with the crystallographically determined trend in Fe-Si distances provided evidence for the presence of a weak dative Fe-Si interaction which is more substantial in the latter species than the former. Crystals of 4a (C14H18FeSi) are orthohombic, space group Pbca, with a = 14.775(2) Å, b = 10.655(2) Å c = 16.882(2) Å, V = 2657.7(7) Å3, and Z = 8. Crystals of 8 (C20H30FeSi) are monoclinic, space group C2/c, with a = 15.687(3) Å, b = 9.194(1) Å, c = 26.612(5) Å, β = 98.65(2)°, V = 3653(6) Å3, and Z = 8. © 1995 American Chemical Society.

Review: syntheses as well as investigations of their unique structures and electronic roperties; 115 refs.

The quantitative conversion of the tertiary stannane (n-Bu)3SnH (2) into (n-Bu)6Sn2 (4) was achieved by heating the neat hydride material under low pressure or under closed inert atmosphere conditions. A 31% conversion of Ph3SnH (3) to Ph6Sn2 (5) was also observed under low pressure; however, under closed inert atmosphere conditions afforded Ph4Sn (6) as the major product. A mixed distannane, (n-Bu)3SnSnPh3 (7), can also be prepared in good yield utilizing an equal molar ratio of 2 and 3 and the same reaction conditions used to prepare 4. This solvent-free, catalyst-free route to distannanes was extended to a secondary stannane, (n-Bu)2SnH2 (8), which yielded evidence (NMR) for hydride terminated distannane H(n-Bu)2SnSn(n-Bu)2H (9), the polystannane [(n-Bu)2Sn]n (10), and various cyclic stannanes [(n-Bu)2Sn]n=5,6 (11, 12). Further evidence for 10 was afforded by gel permeation chromatography (GPC) where a broad, moderate molecular weight, but highly dispersed polymer, was obtained (Mw = 1.8 × 104 Da, polydispersity index (PDI) = 6.9) and a characteristic UV–vis absorbance (λmax) of ≈370 nm observed.

Two perfluorinated potentially polymerizable dichlorostannane monomers, R2SnCl2, [R = (p-CF3C6H4), ((3,5-CF3)2C6H3)] have been prepared in good yield by the comproportionation reactions of the corresponding tetrarylstannanes (1, 2) and tin tetrachloride. The chlorinated monomers 5 and 6 were characterized by X-ray crystallography, 1H, 13C, and 119Sn NMR spectroscopy. The Wurtz coupling behaviour of these dichloromonomers with Na metal in the presence of 15-Crown-5 was also investigated and moderate to very high molecular weight polystannanes 8 and 9 where detected by GPC (Mw = 1.1–1.5 × 105 Da). The introduction of perfluorinated, strongly electron-withdrawing substituents on the phenyl rings of the resulting polystannanes causes a considerable blue-shift (>50 nm) of the σ–σ* λmax transition relative to that of polydiphenylstannane. The perfluorinated groups were designed to impart improved moisture stability relative to non-fluorinated analogues. The new polymers 8 and 9 were found to be extremely light sensitive and readily degraded to oligomeric species upon exposure to ambient light.

The solvent-free, Pt-catalyzed desilylative coupling reaction of 1,1′-bis(dimethylsilyl)ferrocene (12) at elevated temperature leads to the elimination of one dimethylsilane unit and the concomitant oligomerization of ferrocenes with a single dimethylsilyl bridge in low to moderate yields. Air- and moisture-stable oils of the dimer (13) and trimer (14) species possessing dimethylsilyl bridges and terminal dimethylsilane end groups have been isolated by preparative TLC and characterized by HR-MS, elemental analysis, and NMR spectroscopy.

Low to moderate molecular weight substituted polyferrocenylenes [(η5-C5H3X)Fe(η5-C5H3X)]n (where 3a−3c, X = H, SiMe3, Me) were prepared from the Ullmann coupling reaction of the diiodoferrocenes, (η5-C5H3XI)2Fe (2a−2c), with an excess of copper metal or alternatively CuCl-facilitated coupling of the bis(stannyl)ferrocene, (η5-C5H3SiMe3SnBu3)2Fe (1b). The new monomers were characterized by 1H and 13C NMR spectroscopy, elemental analysis and mass spectrometry. A single-crystal X-ray diffraction study (η5-C5H3SiMe3I)2Fe (2b) shows the disubstituted cyclopentadienyl rings are eclipsed with the substituents staggered by 20°. The molecular weights (Mw) for the soluble homopolymers 3b and 3c were estimated by gel permeation chromatography in THF vs polystyrene standards and were found in the range from 2.0 × 103 to 1 × 104 with generally broad polydispersities (PDI > 2). Polymers 3b and 3c were characterized by 1H and 13C NMR spectroscopy and elemental analysis. The polymer thermal transition behavior and morpho...

The synthesis and characterization of two rare examples of the nickel(II)-containing trinuclear clusters of the general formula μ(3)-halido-μ(3)-hydroxotris(μ-halido)tris(L) trinickel(II) halide [halide = Cl (2), Br (3); L = 4,4-dimethyl-2-(o-anilinyl)-2-oxazoline] are described. These materials are compared and contrasted to the "parent" chloride salt (1) of this series (L = N,N,N',N'-tetramethylethylene-1,2-diamine and halide = Cl) and its congeners; 2 and 3 represent the first oxazoline-containing clusters of this structural class. Both 1 and 2 are shown to be active catalysts for the polymerization of olefins (styrene, methyl methacrylate, etc.) using a stoichiometric equivalent of methylaluminoxane as the copromoter, a situation that gives good yields of syndiotactic rich polymers. Density functional theory (B3LYP/6-31G*/LANL2DZ) is employed to hypothesize the likely origin of the activity demonstrated by these compounds.

A coating of Nylon 6,6 or 6,12 was used to improve the penetration resistance of ultra high molecular weight polyethylene (UHMWPE) fabric that would be potentially useful in the manufacture of flexible body armor against spike/knife threats. Quasi-static test results for the spike penetrator showed a 77% and 86% improvement in the puncture resistance of Nylon 6,6 and Nylon 6,12 coated UHMWPE (respectively) over a neat fabric target of equivalent areal densities. Dynamic impact testing demonstrated dramatic improvement in the puncture resistance of nylon-coated fabrics while only a slight improvement in stab resistance was observed comparing samples with equivalent areal densities. Photography of ruptured areas after quasi-static testing revealed limited fiber motion or fiber stretching with no evidence of fiber pullout for nylon-coated fabric samples in contrast to neat fabric. This suggests that there was a significant increase in energy absorption by nylon-coated fabrics at impact. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40350.

Novel tin-bridged [1]ferrocenophanes (1) undergo ring-opening polymerization to yield unusual bimetallic high-molecular-weight poly(ferrocenylstannane)s (2). They also undergo insertion of platinum to afford a 1-stanna-2-platina[2]ferrocenophane (3).

The silicon-bridged [1]ferrocenophanes Fe(η-C5H4)2SiRR‘ [3 (R = Me, R‘ = Cl), 4 (R = R‘ = Cl)] with chlorine substituent(s) at silicon were prepared via the reaction of Fe(η-C5H4Li)2·TMEDA (TMEDA = tetramethylethylenediamine) with the chlorinated silanes MeSiCl3 and SiCl4, respectively. An X-ray diffraction study of 4 indicated that the cyclopentadienyl rings in this species are tilted by an angle of 19.2(4)°, typical of other structurally characterized silicon-bridged [1]ferrocenophanes. Thermal ring-opening polymerization (ROP) of 3 and 4 at 250 °C yielded the first high molecular weight poly(ferrocenylsilanes) with halogen substituents at silicon, [Fe(η-C5H4)2SiRR‘]n [7 (R = Me, R‘ = Cl), 8 (R = R‘ = Cl)]. Transition-metal-catalyzed polymerization of 3 and 4 with Pd and Pt catalysts also yielded polymers 7 and 8 in solution at room temperature. Polymer 7 was soluble in polar organic solvents and was characterized by 1H, 29Si, and 13C NMR and elemental analysis. In contrast, poly(ferrocenylsilane) 8 was...

A series of high molecular weight poly(ferrocenylgermanes) [Fe(η-C5H3X)2GeR2]n 5a−d (X = H; a, R = Me; b, R = Et; c, R = n-Bu; d, R = Ph) and 7 (X = SiMe3, R = Me) were synthesized via the thermal ring-opening polymerization of the corresponding germanium-bridged [1]ferrocenophanes 4a−d and 6. Poly(ferrocenyldimethylsilane)−poly(ferrocenyldimethylgermane) random copolymer 8 was obtained by the thermal and transition metal-catalyzed ring-opening polymerization of a mixture of the [1]germaferrocenophane [Fe(η-C5H4)2GeMe2] (4a) and the corresponding [1]silaferrocenophane [Fe(η-C5H4)2SiMe2] (2a). The molecular weights for the homo- and copolymers were estimated by gel permeation chromatography in THF versus polystyrene standards and were found to be in the range of Mw = 5.0 × 104−2.0 × 106 and with polydispersities in the range of Mw/Mn = 1.2−2.4. A low-angle laser light scattering study of 5a in THF gave an absolute value of Mw of 3.3 × 106, which was significantly greater than the GPC estimate (Mw = 8.2 × 1...

The silicon-bridged [1]ferrocenophane Fe(η-C5H3SiMe3)2(SiMe2) (5) was synthesized via the reaction of Li2[Fe(η-C5H3SiMe3)2]•tmeda (tmeda = tetramethylethylenediamine) with Me2SiCl2 in hexanes. The disilane-bridged [2]ferrocenophane Fe(η-C5H3SiMe3)2(Si2Me4) (7) was prepared using a similar route from the disilane ClMe2SiSiMe2Cl. Despite the presence of sterically demanding SiMe3 substituents on the cyclopentadienyl rings, compound 5 was found to undergo thermal ring-opening polymerization at 170 °C to produce very soluble, high molecular weight poly(ferrocenylsilane) 6 with Mw = 1.4 × 105, Mn = 8.4 × 104. However, the [2]ferrocenophane 7 was found to be resistant to thermal ring-opening polymerization even at 350 °C and decomposed above 380 °C. A single-crystal X-ray diffraction study of 7 revealed that the steric interactions between the bulky SiMe3 groups are relieved by a significant twisting of the disilane bridge with respect to the plane defined by the centroids of the cyclopentadienyl ligands and the metal atom. The angle between the planes of the cyclopentadienyl rings in 7 was found to be 5.4(6)°, slightly greater than that in the non-silylated analogue Fe(η-C5H4)2(Si2Me4) (4a) (4.19(2)°), and dramatically less than the corresponding tilt angle of the strained, polymerizable, silicon-bridged [1]ferrocenophane Fe(η-C5H4)2(SiMe2) (1) (20.8(5)°). The length of the Si—Si bond in 7 (2.342(3) Å) was found to be close to the sum of the covalent radii (2.34 Å). Crystals of 7 are monoclinic, space group C2/c, with a = 23.689(3) Å, b = 11.174(1) Å, c = 31.027(3) Å, β = 109.16(1)°, V = 7758(2) Å3, and Z = 12. Keywords: ring-opening polymerization, ferrocenophane, organometallic polymers.

The strained, silicon-bridged [l]ferrocenophane Fe(η-C 5 H 4 ) 2 SiH 2 (4) was prepared via the reaction of H 2 SiCl 2 with Fe(η-C 5 H 4 Li) 2 .TMEDA in ether at < -78°c. This species was analyzed by single-crystal X-ray diffraction and was found to possess a strained, ring-tilted structure similar to those of previously reported silicon-bridged [l]ferrocenophanes [tilt angle 19.1(1)°]. Thermal ring-opening polymerization of 4 afforded the poly(ferrocenylsilane) [Fe(η-C 5 H 4 ) 2 SiH 2 ] n (5), which was found to be insoluble in common organic solvents. Under the same conditions, mixtures of 4 and the dimethyl analog Fe(η-C 5 H 4 ) 2 SiMe 2 (1a) afforded soluble copolymers 7a-c, consisting of random ferrocenyldihydrosilane and ferrocenyldimethylsilane repeat units, as the first examples of poly(ferrocenylsilane) copolymers prepared via ring-opening polymerization. Repeat unit composition of the random copolymers could be controlled by manipulation of the monomer ratio and was readily assessed by l H NMR spectroscopy. TGA of 5 under N 2 at a heating rate of 10 °C/min found this material to be the most thermally stable to weight loss of all the poly(ferrocenylsilanes) yet studied with only 10% weight loss up to 600 °C and a ceramic yield of 63% at 1000 °C. Among copolymers 7a-c, thermal stability to weight loss increased with increasing ferrocenyldihydrosilane repeat unit content. The homopolymer 5 was found to be crystalline by wide-angle X-ray scattering, and a melting transition at 165 °C was detected by DSC. Glass transitions for the essentially amorphous copolymers were observed to fall between the T g of 18 °C observed for 5 and the T g of 33 °C reported for [Fe(η-C 5 H 4 ) 2 SiMe 2 ] n (2a).

The first silicon-bridged [1.1]ferrocenophane, [{Fe(η-C5H4)2SiMe2}2]5, was prepared in five steps starting from [Fe(η-C5H4Li)2]·tmen (tmen =N,N,N′,N′-tetramethylethylenediamine). Reaction of [Fe(η-C5H4Li)2]·tmen with SiMe2Cl(NEt2) afforded [Fe{η-C5H4SiMe2(NEt2)}2]6 in high yield. Substitution of the silylamine groups of 6 for chlorine by reaction with acetyl chloride gave the dichloro species [Fe(η-C5H4SiMe2Cl)2]7 also in high yield. Reaction of 7 with Li(C5H5) in tetrahydrofuran produced the intermediate [Fe{η-C5H4SiMe2(C5H5)}2], which was subsequently lithiated and treated with FeCl2 to yield 5, in moderate yield. A single crystal X-ray diffraction analysis of compound 5 revealed that the two ferrocene halves are in an anti conformation, with a Fe ⋯ Fe distance of 5.171 (9)A. Cyclic voltammetric analysis of 5 in CH2Cl2 showed the presence of two reversible oxidation waves with a separation of 0.25 V consistent with an extensive interaction between the Fe centres. The room-temperature 57Fe Mossbauer spectrum of 5 is similar to that of 1,1′-bis(trimethylsilyl)ferrocene with an isomer shift of 0.44(1) mm s–1 and a quadrupolar splitting value of 2.32(1) mm s–1. Compound 5 was found to be resistant to thermal ring-opening polymerization and attempted copolymerization with the strained silicon-bridged [1]ferrocenophane [Fe(η-C5H4)2SiMe2] also proved unsuccessful.

A reinvestigation of Pd-catalysed alkyne (R'-C≡CH; R' = H, Ph) insertion chemistry involving R(3)SnSnR(3) (3a: R = Me; 3b: R = n-Bu) was undertaken. Model distannyl ethylenes 4a-b (Me(3)SnCH=CR'SnMe(3)) and 5a-b ((n-Bu)(3)SnCH=CR'Sn(n-Bu)(3)) were reproduced and further characterized by NMR ((119)Sn, (13)C, (1)H) and UV-Vis spectroscopy. In the presence of an excess of phenylacetylene, dimerization-carbostannylation of compound 4b yielded the new conjugated butadiene, (Z,Z)-1,4-bis(trimethylstannyl)-1,4-diphenyl-buta-1,3-diene (9). An X-ray structure determination of 9 reveals a symmetrical double-bond Z confirmation. Compound 9 was further characterized by NMR, UV-Vis spectroscopy, and MS. A DFT analysis of model compounds (4a-b, 5a-b, 9) and the experimental and theoretical λ(max) values from the UV-Vis spectra were also compared. Acetylene and phenylacetylene Pd-catalysed insertion into the backbone of poly[di-(n-butyl)]stannane 12 resulted in new, modest molecular weight, partially inserted alkene tin polymers (13a-b) that were also characterized by GPC, NMR, UV-Vis spectroscopy and elemental analysis.

Sodium dichloroisocyanurate (NaDCC) is a chemical agent that acts against microorganisms in a manner similar to that of sodium hypochlorite by releasing free available chlorine. NaDCC has been approved by the WHO for the emergency treatment of water and by the US EPA for routine treatment of water. Previous studies assessing the effectiveness of NaDCC for the treatment of water implied that NaDCC should have a wide array of disinfecting effects beyond the treatment of planktonic cells in potable water. In this study the biocidal effects of NaDCC against Pseudomonas aeruginosa cells in different growth modes including planktonic cells and biofilms were explored. The data showed that a 60% dilution of the standard NaDCC solution was effective in the treatment of both P. aeruginosa planktonic cells and biofilms.