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Background Crohn’s disease (CD) can develop fistulizing complications at any time during the disease course. Enterocutaneous fistulas (ECF) are disabling lesions with a significant impact on quality of life. The aim of this study was to describe the characteristics and natural history of ECF complicating CD, and to analyze its medical and/or surgical management. Methods A retrospective analysis of all adult patients with fistulizing CD with at least one episode of ECF from the ENEIDA registry (over 68,000 patients) was performed. ECF were defined as a communication between the gastrointestinal tract and the skin producing leakage of luminal contents. Additional data describing the ECF and its medical or surgical management were gathered. The main endpoint was any ECF-related surgical intervention. Fistula closure was defined as the absence of drainage, with no new abscess or surgery for at least 6 months. A comparison of the characteristics and outcomes after the availability of biologic agents (Jan/2000) was also performed. The baseline characteristics were analyzed by means of descriptive statistics and were compared by non-parametric tests. Factors associated with surgery were further evaluated in a binary multivariable regression and survival analysis. Results A total of 301 ECF in 286 patients from 46 hospitals diagnosed between Jan/1970-Sept/2020 were included (median age 34 years (IQR, 27–46); 59% male; 67% L3). ECF had a median of 1 external opening (range 1–10), 59% with concomitant internal fistulas, and usually involved the ileum (67%) or colon (23%). After 146 months (IQR, 69–233) of follow-up, 37% received thiopurines, 40% anti-TNF, 6% ustekinumab and 2% vedolizumab. Surgery was performed in 208 patients (69%) after a median of 4 months (IQR, 1.4–12). Fistula closure was achieved in 253 patients (84%) after 30 months (IQR, 4–84), mostly after surgery (54%) and in one third after medical therapy. Fistula recurrence was uncommon (11%) after closure. Patient and fistula characteristics were significantly different after the availability of biologics. In fact, anti-TNF biologics and thiopurines reduced surgery risk (HR 0.5; 0.38–0.67; HR 0.64; 0.47–0.86, respectively). The surgery rate in the biologic era tends to be lower than before (OR 0.63;0.33–1.09) while timing is similar. Closure rates are also comparable, but it was obtained more frequently after medical therapy once biologicals were available (OR 2.21; 1.13–4.29). Conclusion ECF complicating CD entail a high burden of medical and surgical resources. Closure rates are high, usually after surgery, and fistula recurrence is uncommon. A number of patients can benefit from medical therapy and achieve fistula closure.

Background Three anti-TNFs (one intravenous and two subcutaneous) are licensed for the treatment of ulcerative colitis (UC). However, it is not known if the efficacy of a second anti-TNF changes on whether it is intravenous or subcutaneous; this could justify the indication of biological agents with a different mechanism of action in second line. The aim of this study was to compare the efficacy of a second subcutaneous or intravenous anti-TNF in UC. Methods Patients from the prospectively maintained ENEIDA registry treated with consecutively intravenous and subcutaneous anti-TNF, who were naïve to biological agents, were identified. Patients were classified according to the administration route of the first anti-TNF in: IVi (intravenous initially) or SCi (subcutaneous initially). Patients treated for extraintestinal manifestations or pouchitis were excluded. Clinical activity and effectiveness were defined based on Partial Mayo Score (PMS) at baseline, 14 and 52 weeks. Loss of response, dose-escalation and treatment discontinuation were also assessed. Results 372 UC patients were included (270 IVi and 102 SCi). Both cohorts were similar in clinical-epidemiological characteristics, except for a higher proportion of patients with moderate-to-severe clinical activity at the beginning of the first anti-TNF in the IVi group (82% vs. 71%; p = 0.017) and at the beginning of the second anti-TNF (62% vs. 74%; p = 0.04). Clinical response and remission rates at week 14 for the second anti-TNF were 41% and 29% in IVi vs. 47% and 25% in SCi, respectively (p = ns). At week 52, clinical response/remission rates of the second anti-TNF were 37%/32% in IVi vs. 40%/29% in SCi (p = ns). A higher response rate at 14 weeks with the second anti-TNF was detected in the SCi group (40% vs. 68%; p = 0.012) when the reason for withdrawal of the first anti-TNF was secondary loss of response. The cumulative persistence of the second anti-TNF treatment in IVi and SCi were 55% and 54% after 1 year, and 41% and 40% after 2 years, respectively (p = ns). The SCi group had lower rates of dose-escalation with the second anti-TNF than IVi (34% and 29% in SCi vs. 57% and 49% in EVi, at 12 and 24 months, respectively -p = 0.004-). Dose-escalation of the first anti-TNF and moderate-to-severe clinical activity at the beginning of the second anti-TNF were associated with a lower probability of remission with the second anti-TNF in the short- and long-term. Conclusion The efficacy of infliximab after failure/intolerance of a subcutaneous anti-TNF is similar to that of subcutaneous anti-TNFs after infliximab failure/intolerance.

T1 colorectal polyps with at least 1 risk factor for metastasis to lymph node should be treated surgically and are considered endoscopically unresectable. Optical analysis, based on the Narrow-Band Imaging International Colorectal Endoscopic (NICE) classification system, is used to identify neoplasias with invasion of the submucosa that require endoscopic treatment. We assessed the accuracy of the NICE classification, along with other morphologic characteristics, in identifying invasive polyps that are endoscopically unresectable (have at least 1 risk factor for metastasis to lymph node).We performed a multicenter, prospective study of data collected by 58 endoscopists, from 1634 consecutive patients (examining 2123 lesions) at 17 university and community hospitals in Spain from July 2014 through June 2016. All consecutive lesions10 mm assessed with narrow-band imaging were included. The primary end point was the accuracy of the NICE classification for identifying lesions with deep invasion, using findings from histology analysis as the reference standard. Conditional inference trees were fitted for the analysis of diagnostic accuracy.Of the 2123 lesions analyzed, 89 (4.2%) had features of deep invasion and 91 (4.3%) were endoscopically unresectable. The NICE classification system identified lesions with deep invasion with 58.4% sensitivity (95% CI, 47.5-68.8), 96.4% specificity (95% CI, 95.5-97.2), a positive-predictive value of 41.6% (95% CI, 32.9-50.8), and a negative-predictive value of 98.1% (95% CI, 97.5-98.7). A conditional inference tree that included all variables found the NICE classification to most accurately identify lesions with deep invasion (P.001). However, pedunculated morphology (P.007), ulceration (P = .026), depressed areas (P.001), or nodular mixed type (P.001) affected accuracy of identification. Results were comparable for identifying lesions that were endoscopically unresectable.In an analysis of 2123 colon lesions10 mm, we found the NICE classification and morphologic features identify those with deep lesions with96% specificity-even in non-expert hands and without magnification. ClinicalTrials.gov number NCT02328066.

The reaction under very mild conditions of the polyspirophosphazene copolymer with pendant diphenylphosphine groups {[NP(O2C12H8)]0.85[NP(OC6H4PPh2)2]0.15}n (I) (O2C12H8= 2,2’-dioxybiphenyl) with [Au(THT)Cl] (THT = tetrahydrothiophene) gives the neutral polymeric complex {[NP(O2C12H8)]0.85[NP(OC6H4PPh2-AuCl)2]0.15}n (II). The new material has been characterized by spectrocopic and thermochemical methods (TGA and DSC). Pyrolysis of the Au polymer (I) in air at 800 °C gave gold nanostructured materials that were characterized by TEM, SEM-EDAX and X-ray diffraction. Nanoparticles in the range of 90 to 130 nm were seen.

The reaction of [NPCl2]n first with 2,2'-dihydroxybiphenyl and K2CO3 or (R)-(+)-2,2'-dihydroxy-1,1'-binaphthyl and Cs2CO3, and subsequently with HO−C6H4−CO2Prn and Cs2CO3, gave the phosphazene copolymers {[NP(O2C12H8)]1-x[NP(O−C6H4−CO2Prn)2]x}n [x = 0.2 (1a), 0.35 (1b), 0.5 (1c), 0.7 (1d), and 0.85 (1e)] and the chiral analogues {[NP(O2C20H12)]1-x[NP(O−C6H4−CO2Prn)2]x}n [x = 0.2 (2a), 0.4 (2b), 0.45 (2c), 0.5 (2d), 0.55 (2e), 0.7 (2f), and 0.8(2g)]. The study of their properties as a function of the composition have revealed systematic changes in the electronic structure of the macromolecules, in the interplanar distances of their mesophases and in glass transition temperatures. The latter variation has demonstrated the strictly alternating nature of the copolymeric structures in the series 1 and 2. This is an experimental evidence supporting that the substitution of Cl in the [NPCl2]n with the bifunctional reagents or 2,2'-dihydroxybiphenyl and (R)-(+)-2,2'-dihydroxy-1,1'-binaphthyl as promoted by alkali...

The reactions of the spirocyclic phosphazene [N 3 P 3 (O 2 C 12 H 8 ) 2 Cl 2 ] (O 2 C 12 H 8 = 2,2'-dioxybiphenyl) with the thiophenols HS--C 6 H 4 --R and M 2 CO 3 (M = K or Cs) in refluxing acetone gave respectively the spirocyclic substituted derivatives [N 3 P 3 (O 2 C 12 H 8 ) 2 (SC 6 H 4 --R) 2 ] R = H ( 2a ), Br ( 2b ), OMe ( 2c ), NO 2 ( 2d ). The reaction is a two-step process the second of which is much faster than the first and the monosubstituted intermediate [N 3 P 3 (O 2 C 12 H 8 ) 2 (SC 6 H 4 --R)Cl] cannot be detected. By contrast, in the analogous reactions with the phenols HO--C 6 H 4 --R and M 2 CO 3 (M = K or Cs) in acetone or THF, to give the known derivatives [N 3 P 3 (O 2 C 12 H 8 ) 2 (OC 6 H 4 --R) 2 ], the first step is faster although both are very dependent on R, M and the solvent. Thus, in the case of the phenol HO--C 6 H 4 --OMe the reaction conditions could be adjusted to give the useful synthetic intermediate monosubstituted derivative [N 3 P 3 (O 2 C 12 H 8 ) 2 (OC 6 H 4 --...

The outcome of the reaction of the bifunctional reagent p-aminophenol (HO-C6H4-NH2) with the cyclic triphosphazene [N3P3Cl6] is very dependent on the solvent, the temperature, and the proton abstractor. In THF at room temperature with K2CO3 the reaction is very slow and takes place only through the NH2 group to give a mixture of aminophosphazenes, but in refluxing acetone with Cs2CO3 the reaction is fast and occurs through both the NH2 and the OH groups leading to crosslinked products. The analogous reaction with the bis-spirocyclodichlorotriphosphazene [N3P3Cl2(O2C12H8)2] (O2C12H8 = 2,2′-dioxybiphenyl) is also dependent on the conditions, but is more selective. At room temperature in THF with K2CO3 the reaction gives mostly aminophosphazene derivatives, while in refluxing acetone with Cs2CO3 the known aryloxyphosphazene [N3P3(OC6H4NH2)2(O2C12H8)2] (1) is obtained exclusively. Accordingly, the reactions of p-aminophenol with high molecular weight poly(dichlorophosphazene) [NPCl2]n in THF at room temperature in the presence of K2CO3, occur exclusively through the NH2 groups without crosslinking, forming solutions of the aminophosphazene random copolymers {[NPCl2]1−x[NPCl(NHC6H4OH)]x}n (2a) (x 1) that carry terminal OH groups. The reaction of 2a with NH2Bu (Bu = n-butyl) gave the stable and soluble polymers {[NP(NHBu)2]1−x[NP(NHBu)(NHC6H4OH)]x}n (3). Also, in agreement with the cyclic models, the reaction of p-aminophenol with the partially substituted copolymer {[NP(O2C12H8)]0.8[NPCl2]0.2}n occurs only at refluxing temperatures and in the presence of Cs2CO3, producing the poly(aryloxyphosphazene) derivative {[NP(O2C12H8)]0.8[NP(OC6H4NH2)2]0.2}n (4) possessing terminal NH2 groups, or, if the chlorine substitution is completed with phenol, the analogous polymer {[NP(O2C12H8)]0.8[NP(OC6H5)(OC6H4NH2)]0.2}n (5). (© Wiley-VCH Verlag GmbH, 1 Weinheim, Germany, 2002)

Magnetization reversal processes have been studied in hybrid magnetic/superconducting Nd-Co/Nb bilayers by the comparison of out-of-plane magnetic hysteresis loops and superconducting phase diagrams as a function of magnetic layer thickness and of disorder in the magnetic layer induced by a nanostructured copolymer template. A good correlation is found between the regimes corresponding to percolation effects in the superconductor and to the transition from extended to confined superconductivity with the characteristic fields for reverse domain nucleation and fast domain expansion in the magnetic layer, indicating that superconductivity nucleates on the disordered network imprinted on the superconducting layer by the labyrinth domain structure of the magnetic layer. As disorder increases in the magnetic layer, percolation effects disappear from the superconducting transitions in agreement with a more homogeneous magnetization reversal process. © 2014 AIP Publishing LLC., This work was supported by Spanish MINECO under grants FIS2008-06249 and Consolider CSD2007-00010 and by CAM under grant S2009/MAT-1726.

The second-harmonic response of 4-[(4‘-nitrophenyl)azo]phenoxy- doped polyphosphazene (PPZ) films with high glass-transition temperatures (Tg∼ 150 °C) has been investigated. The nonlinear chromopho...

Polyphosphazenes with high glass-transition temperatures have been prepared according to a newly developed synthetic route. The 4-[(4'-nitrophenyl)azo]phenoxy chromophore has been incorporated as a side-chain group in a concentration around 30% by weight. The nonlinear optical (NLO) properties of polyphosphazene films have been studied. The three components of the second-order NLO susceptibility tensor for corona poled films are X (2) 15 = 9.3 x 10 -24 C/V 2 (2.5 x 10 -9 esu), X (2) 31 = 9.6 x 10 -24 C/V 2 (2.6 × 10 -9 esu) and X (2) 33 = 28.2 × 10 -24 C/V 2 (7.6 x 10 -9 esu) for a poling field of 6 kV and a temperature of 140°C. The Kleinman symmetry and the condition X (2) 33 = 3X (2) 31 are approximately obeyed within the experimental error. At room temperature (RT), the thermal stability of the second-order NLO response is very high since the X (2) 15 value decreases by less than 10% in 70 days. The third-order NLO susceptibility has also been determined and reaches 0.38 × 10 -31 C m/V 3 (0.31 × 10 -12 esu) for the unsubstituted polymer and 3.2 × 10 -31 C m/V 3 (2.6 x 10 -12 esu) for the substituted (side-chain) one.

Planar optical waveguides of some novel phosphazene inorganic polymers with high glass transition temperatures, T g > 150° C, have been prepared by spin-coating on glass and quartz substrates. Thicknesses between 0.5 and 2 μm and index steps of about An ∼0.2 (for quartz) and An ∼0.1 (for glass) at λ = 0.633 μm have been achieved. From one to five modes have been observed at wavelengths ranging from the green to the near infrared. Refractive indices have been well fitted to a Sellmeier dispersion equation. Waveguide losses are estimated to be around 10 dB/cm.

The vibrational spectra of three cyclic phosphazene molecules, [N3P3Cl4(O2C12H8)] (CP1), [N3P3Cl2(O2C12H8)2] (CP2) and [N3P3(O2C12H8)3] (CP3), are reported. The far-infrared, infrared and Raman spectra were recorded. The assignment of fundamental vibrational modes is assisted by quantum chemical computations of wavenumbers and Raman and infrared intensities. Fundamental vibrational modes characterized by wavenumber and intensity are identified in the infrared and Raman spectra of the series. Copyright © 1999 John Wiley & Sons, Ltd.

The direct reaction of [NPCl2]n with the difunctional reagent 2,2‘-dihydroxybiphenyl (HOC6H4C6H4OH) and K2CO3 in tetrahydrofuran gave soluble linear phosphazene high polymers instead of the expected cross-linked products. The reaction of [N3P3Cl6] with 1, 2, or 3 equiv of HOC6H4C6H4OH and K2CO3 in acetone gave the known spiro derivatives [N3P3Cl4(O2C12H8)], [N3P3Cl2(O2C12H8)2], and [N3P3(O2C12H8)3] without formation of bridging products, and the dichloro derivative reacted directly with para-substituted phenols HOC6H4R and K2CO3 in acetone to give the new compounds [N3P3(OC6H4R)2(O2C12H8)2] (R = Br, COC6H5, or OCH3), without signs of replacement of the bis(aryloxy) substituents. In an analogous manner, poly(dichlorophosphazene) [NPCl2]n reacted with HOC6H4C6H4OH and K2CO3 in THF without significant cross-linking to give, depending on the mole ratio, the soluble polymer [NP(O2C12H8)]n (Mw = 450 000, Tg = 160 °C) or the partially substituted polymers {[NP(O2C12H8)]0.35[NPCl2]0.65}n. The latter were subseque...

The use of deprotonation-substitution reactions on poly(alkyl/arylphosphazenes) for the preparation of new types of poly(phosphazenes) is summarized. Emphasis is placed on those with metal-containing side groups. The coordination of lithium and silver tetrafluoroborate to the backbone of [Me(Ph)PN]n and [Me2PN]n is also discussed. In the second part of this paper, the synthesis and characterization of new types of the μ-phosphorus-bridged diiron compounds are reviewed. Many of these incorporate amino and silylamino substituents and are derived from the reactions of low-coordinate P-N compounds with the diiron ion, [(μ-CO)(μ-S-t-Bu)Fe2(CO)6]−.

In the present investigation we ascertained the stability of lycopene, beta-carotene, ascorbic acid, polyphenolic compounds and total antioxidant capacity (AC) during the process of concentrating tomatoes into two tomato pastes (10 and 15 degrees Brix). Thermal processing increased the content of lycopene, total phenolic compounds, total flavonoids, and the individual phenolic compounds quercetin, rutin, chlorogenic and cafeic acids, whereas it decreased the other analysed compounds. However, lycopene in the 15 degrees Brix-tomato paste decreased due to the extension of thermal processing, which led to degradation. The AC of aqueous and organic extracts was measured and different AC values were observed depending on the antioxidant profile of the extract and assay used (TEAC and FRAP). AC expressed in dry matter decreased as result of ascorbic acid losses. Overall, thermal processing enhanced the nutritional value of tomatoes, mainly by increasing the lycopene and phenolic antioxidants, but the extension of treatment must be controlled to prevent lycopene degradation.

The unsaturated dihydrides [Mn2(µ-H)2(CO)6(µ-L–L)][L–L = Ph2PCH2PPh2(dppm)1; or (EtO)2POP(OEt)2(tedip)2] react with sulfur to yield the hydrogensulfido complexes [Mn2(µ-H)(µ-SH)(CO)6(µ-L–L)](L–L = dppm 3a; or tedip 3b). The hydrogen bound to the sulfur atom in 3a is easily removed by thallium(I) acetylacetonate, generating a species which affords, upon reaction with the appropriate electrophiles, the thiolato complexes [Mn2(µ-H)(µ-SZ)(CO)6(µ-dppm)](Z = Me 3c, SnMe33d, or AuPPh33e). The solid-state structure of 3e has been determined by X-ray methods [monoclinic, space group P21/n, a= 18.840(4), b= 13.024(2), c= 20.243(4)A, β= 108.66(2)°, Z= 4].

The unsaturated dihydrides [Mn2(μ-H)2(CO)6(μ-LL)] (LL = Ph2PCH2PPh2, dppm, 1; (EtO)2POP(OEt)2, tedip, 2) react with carbon dioxide (at 50 atm) or with formic acid to yield not only the expected hydridoformate complexes [Mn2(μ-H)(μ-O2CH)(CO)6(μ-LL)] (LL = dppm, 3a; tedip, 3b but also the hydridohydroxo-derivatives [Mn2(μ-H)(μ-OH)(CO)6(μ-LL)] (LL = dppm, 4a; tedip, 4b. The complexes 4 do not seem to arise from decomposition of 3 or to be products of the reaction of 1 and 2 with water. The hydrides 1 and 2 also react under mild conditions with several heterocumulenes (cyclohexylisocyanate, dicyclohexylcarbodiimide and trimethylsilylazide) to afford [Mn2(μ-H){μ-OC(H)NCy}(CO)6Iμ-tedip)] (5), [Mn2(μ-H{μ-CyNC(H)NCy}(CO)6(μ-LL)] (LL = dppm, 6a; tedip 6b and [Mn2(μ-H)(μ-N3)(CO)6(μ-LL)] (LL = dppm, 7a: tedip, 7b), respectively.

Several manganese carbonyl complexes of the type [Mn(CO)m(CNtBu)n(L)p(LL)]ClO4 (m + n + p = 4; m = 1−3; n = 1−3; p = 0, 1; L = P(OMe)3, CNPh; LL = 2,2′-bipiridine (bipy), 1,10-phenantroline (phen), bis(t-butyl)-1,4-diazabuta-2,3-diene (tBu-DAB), N,N,N′,N′-tetramethylethylendiamine (tmed)) have been prepared starting either from fac-[Mn(CO)3(CNtBu)(LL)]ClO4 or fac-[Mn(CO)3{P-(OMe)3}(LL)]ClO4 and using ONMe3 as decarbonylating agent. The stereochemistry of the substitution reactions products is discussed in terms of the nature of the possible intermediates.

The phosphazene copolymers {[NP(O 2 C 12 H 8 )] 0.5 [NP(O–C 6 H 4 –CO 2 Pr n )(O–C 6 H 4 –L)] 0.5 } n [L = CN ( 1 ), PPh 2 ( 2 )] and {[NP(O 2 C 12 H 8 )] 0.6 [NP(O–C 6 H 4 –CO 2 Pr n )(O–C 5 H 4 N)] 0.4 } n ( 3 ) have been synthesized by sequential substitution from [NPCl 2 ] n . Their reactions with [W(MeOH)(CO) 5 ] gives the corresponding tungsten carbonyl complexes {[NP(O 2 C 12 H 8 )] 0.5 [NP(O–C 6 H 4 –CO 2 Pr n )(O–C 6 H 4 –CN)(W(CO) 5 ) 0.4 ] 0.5 } n ( 4 ), {[NP(O 2 C 12 H 8 )] 0.5 [NP(O-C 6 H 4 –CO 2 Pr n )(O–C 6 H 4 –PPh 2 )(W(CO) 5 ) 0.7 ] 0.5 } n ( 5 ), {[NP(O 2 C 12 H 8 )] 0.6 [NP(O–C 6 H 4 –CO 2 Pr n )(O–C 5 H 4 N–W(CO) 5 )] 0.4 } n ( 6a ), and {[NP(O 2 C 12 H 8 )] 0.6 [NP(O–C 6 H 4 –CO 2 Pr n )(O–C 5 H 4 N)(W(CO) 5 ) 0.4 ] 0.4 } n ( 6b ), that have been fully characterized by IR and NMR spectroscopies. The thermal properties (TGA and DSC) of the polymeric complexes showed that they are high glass transition materials that undergo a complete decarbonylation below 300 °C forming metal containing species that have a stabilizing effect on the polymeric matrices. The final residues up to 800 °C are of the order of30–50%.

The high molecular weight phosphazene random copolymer {[NP(OC6H5)2]0.94 [NP(OC6H5)(OC6H4CNFe(dppe)Cp)]0.06[PF6]0.06}n (1), that carries [Fe(dppe)Cp] cationic fragments coordinated to nitrile side groups, has been synthesized from the copolymer {[NP(OC6H5)2]0.94[NP(OC6H5)(OC6H4CN)]0.06}n and the complex [Fe(CH3CN)(dppe)Cp][PF6] by the complete elimination of the acetonitrile from the equilibrium mixture that they form in dichloromethane solution. The new polymer has been fully characterized by a detailed discussion of the IR and NMR data that may be also useful for the study of other polymeric complexes with similar metal fragments. The cyclic voltammogram of (1) showed an oxidation process that is chemically irreversible but, rather unexpectedly, electrochemically reversible. All the results were interpreted by comparison with the data obtained for the new cyclic model complexes {N3P3(OC6H4-R)5[OC6H4CNFe(dppe)Cp]}[PF6] R=H (2a), Bu t (2b), (see chart 1) that were synthesized by a similar method using the nitrile phosphazene ligands [N3P3(OC6H4-R)5(OC6H4CN)]

The structure and the assembly of tris-(2,2'-dioxy-binaphthyl)cyclotriphosphazene [(+)-[NP3(O2C20H12)3], DBNP, in the solid amorphous state was studied using molecular dynamics (MD) including ad hoc quantum mechanically derived force field (FF) parameters, in combination with the energy dispersive X-ray diffraction (EDXD) technique. The atom-atom radial distribution function (RDF) curve obtained through the EDXD experiment revealed low intensity peaks not attributable to the intramolecular distances of the single molecule, but clearly featuring a low energy state of long-distance three-dimensional assembly. The radial distribution functions (RDF) were calculated for various models of DBNP submitted to theoretical MD simulations. Based on the comparison of theoretically calculated RDFs and those obtained from the EDXD experiment, the predominant structural motif of the material in the bulk was found to have DBNP molecules laid one upon the other to form tubular nanostructures. These contain eight DBNP units each (length ca. 46 A) with two and three of these units aligned in parallel and held together. The material can be represented as a bulk of tubular snake-like chains undergoing distortions with a step of eight DBNP units. The bending angles, that vary randomly, attain limited values sufficient to induce disorder and thus nonperiodic structure. The present application of MD simulations combined with EDXD data appear to be a general approach to solve for the first time otherwise intractable issues concerning structural features and assembly of molecular materials in the bulk.

The reaction of [NPCl2]n with substoichiometric amounts of the thiophenols HS—C6H4—R (R = H, Br) and Cs2CO3 in THF at room temperature, gave solutions of {[NPCl2]1-x[NP(S—C6H4—R)2]x}n [R = H (1a), Br (1b)]. The reaction of the derivative with R = Br and x = 0.3 with HO—C6H4—Br gave the random copolymer {[NP(O—C6H4—Br)2]0.7 [NP(S—C6H4—Br)2]0.3}n (2); similarly, the reaction of 1 with the biphenol HO—C6H4—C6H4—OH gave the random copolymers {[NP(O2C12-H8)]0.75[NP(S—C6H4—R)2]0.25}n [R = H, (3a); R = Br, (3b)] as soluble and stable white solids., We thank the Spanish Dirección General de Investigación Científica y Técnica (DGYCYT), Project PB97-1276, for support.

The carbonyls cis,cis -[Mn(CO) 2 (CN-t-Bu) 2 (NN)]ClO 4 and fac -[Mn(CO)(CN-t-Bu) 3 (NN)]ClO 4 , (NN = 2,2′-bipyridine, bpy, and 1,10-phenantroline, phen), are isomerized to cis,trans - and mer -complexes respectively by reduction in acetonitrile with sodium amalgam and subsequent oxidation by air. The structure of fac -[Mn(CO)(CN-t-Bu) 3 (bpy)]ClO 4 has been determined by X-ray diffraction.

The first mer -tricarbonyl complexes of manganese(I) with N -donor chelate ligands, namely mer -[Mn(CO) 3 (CNR)(NN)]ClO 4 , where CNR = CNBu t , NN = 1,10-phenantroline (phen) or 2,2′-bipyridine (bipy), have been obtained from the reactions of fac -[Mn(CO) 3 (Me 2 CO)(NN)]ClO 4 with isocyanides, CNR. Other members of the [Mn(CO) 4- n (CNR) n (NN)]ClO 4 ( n = 1,2,3,4) series have also been synthesized: viz., fac -[Mn(CO) 3 (CNR)(NN)]ClO 4 (Ia-d) and cis,cis -[Mn(CO) 2 (CNR) 2 (NN)]ClO 4 (CNR = CNBu t , CNPh) (IIa-d), cis,cis -)[Mn(CO) 2 (CNR)(CNR′)(NN)]ClO 4 (CNR = CNPh, CNR′ = CNBu t and CNR = CNBu t , CNR′ = CNPh) (IIe-f), fac -[Mn(CO)(CNBu t ) 3 (NN)]ClO 4 , (IVa-b), and [Mn(CNPh) 4 (NN)]ClO 4 ; (NN) represents phen or bipy. (See Scheme 1 and Table 1).

It has been shown that new mer -tricarbonyls mer -[Mn(CO) 3 L(tmed)]ClO 4 , (tmed = N , N , N ′, N ′-tetramethylethylenediamine, L = P(OMe) 3 , P(OEt) 3 , P(O-iPr) 3 ) can be readily obtained from the reaction between fac -Mn(CO) 3 (tmed)Br, AgClO 4 , and L at room temperature, whereas at 0°C fac -isomers are produced. The opposite is the case for L = CN-t-Bu; mer -[Mn(CO) 3 (CN-t-Bu)(tmed)]ClO 4 is observed at 0°C, and the fac -isomer is stable at 25°C.