Simple spectrophotometric method for the estimation of accessible amino groups and preparation of polyurethane nanocomposites.

The chemical and physical properties of [AgO 2 C(CH 2 OCH 2 ) 3 H] (3) and its use as an aqueous, ligand-free MOD ink (MOD = metal-organic decomposition) for piezo inkjet printing is discussed. The printed, thermal, or photochemical sintered silver features are electrically conductive on glass (2.7 Â 10 7 S m -1 ) and PET (PET = polyethylene terephthalate) substrates (1.1 Â 10 7 S m -1 ) corresponding to 43% and 18% of the bulk silver conductivity. Conducted tape tests show the suitability of the ink for particularly polymer substrates. TG-MS studies demonstrate a two-step decomposition for the conversion of 3 to elemental silver. The structure of 3 in the solid state was determined by single X-ray structure determination.

Two from one: It is possible to form two different, interpenetrating polymer structures—silicon dioxide and a phenolic resin—simultaneously in a single step without the formation of by‐products by using a readily polymerizable, organic silicon spiro compound. This new polymerization process enables the fabrication of materials with domain sizes of 0.5 to 3 nm.

Design and synthesis of ordered, metal-free layered materials is intrinsically difficult due to the limitations of vapor deposition processes that are used in their making. Mixed-dimensional (2D/3D) metal-free van der Waals (vdW) heterostructures based on triazine (C N ) linkers grow as large area, transparent yellow-orange membranes on copper surfaces from solution. The membranes have an indirect band gap (E = 1.91 eV, E = 1.84 eV) and are moderately porous (124 m g ). The material consists of a crystalline 2D phase that is fully sp hybridized and provides structural stability, and an amorphous, porous phase with mixed sp -sp hybridization. Interestingly, this 2D/3D vdW heterostructure grows in a twinned mechanism from a one-pot reaction mixture: unprecedented for metal-free frameworks and a direct consequence of on-catalyst synthesis. Thanks to the efficient type I heterojunction, electron transfer processes are fundamentally improved and hence, the material is capable of metal-free, light-induced hydrogen evolution from water without the need for a noble metal cocatalyst (34 µmol h g without Pt). The results highlight that twinned growth mechanisms are observed in the realm of "wet" chemistry, and that they can be used to fabricate otherwise challenging 2D/3D vdW heterostructures with composite properties.

Aus eins mach zwei: Ausgehend von einer leicht polymerisierbaren Silicium‐Spiroverbindung gelingt es, in einem einzelnen Prozessschritt zwei interpenetrierende Polymerstrukturen – SiO2 und Phenolharz – ohne die Bildung von Beiprodukten herzustellen. Diese neue Polymerisationsmethode ist auf verschiedenste Monomere anwendbar und macht Polymermaterialien mit Domänengrößen von 0.5 bis 3 nm zugänglich.

A series of organometallic mono-and disubstituted bis(alkynyl)biferrocenes of type (L n MCtC)-(HCtC)bfc (L n M ) (η 5 -C 5 H 5 )(Ph 3 P) 2 Ru (8a), (η 5 -C 5 H 5 )(Ph 3 P) 2 Os (8b), (η 5 -C 5 H 5 )(dppf)Ru (8c); bfc ) 1′,1′′′-biferrocenyl, ((η 5 -C 5 H 4 ) 2 Fe) 2 ; dppf ) 1,1′-bis(diphenyl)phosphanyl ferrocene, (η 5 -C 5 H 4 PPh 2 ) 2 Fe) and (L n MCtC) 2 bfc (L n M ) (Ph 3 P)Au ( 6), (η 5 -C 5 H 5 )(Ph 3 P) 2 Ru (9a), (η 5 -C 5 H 5 )(Ph 3 P) 2 Os (9b), (η 5 -C 5 H 5 )(dppf)Ru (9c)) have been synthesized from (HCtC) 2 bfc (4) with either (Ph 3 P)AuCl (5) in the presence of HNEt 2 /[CuI] (synthesis of 6) or L n MX (L n MX ) (η 5 -C 5 H 5 )(Ph 3 P) 2 RuCl (7a); (η 5 -C 5 H 5 )(Ph 3 P) 2 OsBr (7b); (η 5 -C 5 H 5 )(dppf)RuCl ( 7c)) together with [H 4 N]PF 6 and KOtBu (synthesis of 8 and 9), respectively. The structures of 6, 8b, 9a, 9b, and 9c in the solid state were determined by singlecrystal X-ray structure analysis, showing unsymmetrical (8) or symmetrical geometries (6, 9), with almost eclipsed conformations or approximately midway positions between the fully eclipsed and the fully staggered conformation of the bfc cyclopentadienyl rings and with anti geometry of the linear ethynyl connecting units. UV-vis and NIR spectroscopic measurements suggest a weak interaction between the appropriate metal atoms. The associated radical cations were in situ generated by stepwise chemical oxidation and characterized by continuous wave electron paramagnetic resonance (EPR) investigations in X-band performed at low temperature.

Treatment of 1 0 ,1 000 -bis(ethynyl)biferrocene (1) with 2 equiv of FeCl(η 2 -dppe)(Cp*) (2) in the presence of [H 4 N]PF 6 produced the vinylidene complex [1 0 ,1 000 -((Cp*)(η 2 -dppe)FedCdCH) 2 bfc][PF 6 ] 2 (3) (97%, Cp*=η 5 -C 5 Me 5 ; dppe=1,2-bis(diphenylphosphino)ethane; bfc=1 0 ,1 000 -biferrocenyl, (η 5 -C 5 H 4 ) 2 Fe) 2 ), while neutral tetranuclear 1 0 ,1 000 -((Cp*)(η 2 -dppe)Fe-CtC) 2 bfc (4) was obtained from the reaction of 3 with KO t Bu (68%). The IR, 1 H, 13 C, and 31 P NMR, cyclic voltammetry, M€ ossbauer, and UV-vis data were obtained for 4. When reacted with 2 equiv of [FcH]PF 6 or TCNQ, complex 4 provided 4[X] 2 (Fc = 1-ferrocenyl, (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 ), X = PF 6 , 89%; X = TCNQ = 7,7,8,8tetracyanoquinodimethane, 91%), and 4[PF 6 ] was obtained by reacting 4 with 4[PF 6 ] 2 in a 1:1 molar ratio (76%). Organometallics 4[PF 6 ] 3 (93%) and 4[PF 6 ] 4 (87%) were obtained from the reaction of 4[PF 6 ] 2 with 1 or 2 equiv of Ag [PF 6 ]. For the purpose of reasonable solubility the triflate salts of tri-and tetracationic species 4[OTf] 3 (94%) and 4[OTf] 4 (95%) were synthesized instead of the hexafluorophosphate salts. The structures of 3, 4, and 4[TCNQ] 2 in the solid state were determined by single-crystal X-ray structure analysis. IR and M€ ossbauer spectroscopy of 4[PF 6 ] n (n=0-4) allowed the stepwise observation of the four metal-centered oxidations and established the localized character of the mixedvalence complexes. EPR spectra of 4[PF 6 ] n (n=1, 3) proved the formation of two radicals, one centered on the half-sandwich termini and the other centered on the (ethynyl)biferrocene bridge, indicating that the mediating state is sufficiently low lying to be populated at 66 K. The NIR spectra of the mixedvalent species 4[PF 6 ] n (n=1, 2) and 4[OTf] 3 showed the presence of two bands, and their characteristic parameters are in accord with an electron transfer involving intermediate states. § Part of the Dietmar Seyferth Festschrift. In honor of Prof. Dr. h.c. mult. Dietmar Seyferth for his outstanding contribution as editor to Organometallics.

The synthesis of a unique series of heteromultinuclear transition metal complexes with up to seven different metal atoms is reported by using consecutive synthesis methodologies including metathesis, dehydrohalogenation, and carbon−carbon cross-coupling reactions. In these compounds the metals Ti, Fe, Ru, Os, Re, Pt, and Cu are connected via carbon-rich bridging units comprising 1,3,5-triethynylbenzene and 2,2′-bipyridyl-5-yl. These molecules have been characterized by elemental analysis, IR and NMR spectroscopy, and ESI-TOF mass spectrometry. The main structural feature of these compounds is an unsymmetrical trans-configurated platinum(II) bis-acetylide unit. The structure of 1-(FcCC)-3-[( t Bu2bpy)(CO)3ReCC]-5-[trans-(Ph3P)2(RcCC)PtCC]C6H3 (3) and 1,3-[(Ph3P)2(η5-C5H5)OsCC]2-5-[(CO)3(Cl)Re(bpyCC)]C6H3 (18) (Fc = (η5-C5H5)(η5-C5H4)Fe; Rc = (η5-C5H5)(η5-C5H4)Ru; t Bu2bpy = 4,4′-di-tert-butyl-2,2′-bipyridyl; bpy = 2,2′-bipyridyl-5-yl) in the solid state is reported. Both compounds are characterized by the central 1,3,5-triethynylbenzene core, bridging the individual transition metal building blocks. These organometallic fragments show thereby typical structural properties. The appropriate metal acetylide moieties are, as expected, found in a linear arrangement with representative M−C and CC bond distances.