Purple Solids Research Articles

The NSN link as electron accepting moiety for stable, solution‐processable conjugated oligomers

AbstractNew conjugated oligomers, oligo(9,9‐didodecylfluorene‐bis‐sulphurdiimide), consisting of 9,9‐didodecylfluorene separated by NSN moieties, are reported. These oligomers are stable purple solids under ambient conditions with absorption covering a broad spectral window in the UV‐vis range and a main broad peak centered at 555 nm with onset extending to 700 nm. These oligomers show an obviously longer conjugation length than its dimeric analogue, bis‐9,9‐didodecyl‐fluorene‐2‐sulfurdiimide that shows a band‐edge absorption centered at 484 nm with onset at 590 nm. The dimer and oligomers are soluble in a variety of organic solvents. Moreover, we found that the oligomer with an average repeating‐unit number of six could significantly quench the photoluminescence (PL) of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene] (MEH‐PPV) or poly(3‐hexylthiophene) (P3HT) in the solid state. More importantly, the composites of this oligomer with P3HT showed a nearly 10‐fold enhancement of the photocurrent, compared with that of P3HT itself. In addition, the PL of this oligomer could be quenched by the presence of phenyl‐C61‐butyric acid methyl ester (PCBM) in toluene. These results suggest the presence of photoinduced charge transfer in composites of these oligomers blended with an electronic partner that either donates or accepts electrons. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Vanadium selenoether and selenolate complexes, potential single-source precursors for CVD of VSe2thin films

Reactions of VCl4 with one mol equiv. of L–L (L–L = MeSe(CH2)2SeMe, MeSe(CH2)3SeMe, nBuSe(CH2)2SenBu) in anhydrous CH2Cl2 solution at room temperature give [VCl4(L–L)] as very moisture-sensitive dark purple solids. Using VCl4 and excess selenoether in gently refluxing CH2Cl2 leads to reduction to [VCl3(L–L)] (L–L as above and o-C6H4(CH2SeMe)2), while VCl4 reacts with excess SeMe2 at room temperature to give [VCl3(SeMe2)2]. All new complexes were characterised by microanalysis, IR and UV/visible spectroscopy and magnetic measurements. Reaction of [(Cp)2VCl2] with two mol equiv. of LiSetBu in anhydrous thf gives the VIV selenolate complex [(Cp)2V(SetBu)2] as a very moisture-sensitive brown solid. The new complexes have been investigated as possible reagents for deposition of vanadium selenide. While low pressure chemical vapour deposition (LPCVD) experiments showed that the diselenoether complexes were not sufficiently volatile for VSe2 deposition, [VCl3(SeMe2)2] gives very thin deposits of VSe2. LPCVD studies on [(Cp)2V(SetBu)2] at 600 °C produce thicker black films of VSe2. In all cases EDX measurements show that the films are Se deficient.

The reactions of some σ-alkynylnickel complexes with 7,7,8,8-tetracyanoquinodimethane

The σ-alkynyl complexes Ni(η 5-C 5H 5)(PPh 3)–C C–R ( 1), Ni(η 5-C 5H 5)(PPh 3)–C C–X–C CH ( 2) and Ni(η 5-C 5H 5)(PPh 3)–C C–X–C C–Ni(η 5-C 5H 5)(PPh 3) ( 3), reactwith 7,7,8,8-tetracyanoquinodimethane, TCNQ, at 30 °C by insertion of the alkyne C C into a C C(CN) 2 bond to give Ni(η 5-C 5H 5)(PPh 3)–C{ C 6H 4 C(CN) 2}–C{ C(CN) 2}–R ( 4), from 1, Ni(η 5-C 5H 5)(PPh 3)–C{ C 6H 4 C(CN) 2}–C{ C(CN) 2}–X–C CH ( 5), from 2, and Ni(η 5-C 5H 5)(PPh 3)–C{ C 6H 4 C(CN) 2}–C{ C(CN) 2}–X–C C–Ni(η 5-C 5H 5)(PPh 3) ( 6),and Ni(η 5-C 5H 5)(PPh 3)–C{ C 6H 4 C(CN) 2}– C{ C(CN) 2}–X–C{ C(CN) 2}–C{ C 6H 4 C(CN) 2}–Ni(η 5-C 5H 5)(PPh 3) ( 7),from 3 {R = (a) C 6H 5, (b) 4-PhC 6H 4, (c) 4-Me 2NC 6H 4, (d) 1-C 10H 7 (1-naphthyl), (e) 2-C 10H 7 (2-naphthyl), (f) 9-C 14H 9 (9-phenanthryl), (g) 9-C 14H 9 (9-anthryl), (h) 3-C 16H 9 (3-pyrenyl), (i) 1-C 20H 11 (1-perylenyl), (j) 2-C 4H 3S (2-thienyl), (k) C 10H 9Fe (ferrocenyl = Fc) and (l) H; X = (a) nothing, (b) 1,4-C 6H 4, (c) 1,3-C 6H 4 and (d) 4,4′-C 6H 4–C 6H 4}. The reaction is regiospecificand the other possible insertion product, R–C{ C 6H 4 C(CN) 2}–C{ C(CN) 2}–Ni(η 5-C 5H 5)(PPh 3) etc., is not formed. Under the same conditions, there is no evidencefor the reaction of TCNQ with the –C CH of 2, PhC CH, 1,4-C 6H 4(C CH) 2 or FcC CH, or for the reaction of more than one C C(CN) 2 of TCNQ with a Ni-alkynyl moiety. Complexes 4– 7 are all air-stable, purple solids which have been characterised by elemental analysis and spectroscopy (IR, UV–Vis, 1H NMR and 13C NMR),and by X-ray diffraction for 4a, 4b and 4l. The UV–Vis spectra of 4– 7 are very similar. This implies that all contain the same active chromophore which, it is suggested, is Ni–C(5) C 6H 4 C(CN) 2 and not R–C(4) C(CN) 2. This isconsistent with the molecular structures of 4a, 4b and 4l which show that the first of these potentially chromophoric fragments is planar or close to it with an in-built potential for delocalisation, whilst in the second the aryl group R is almost orthogonal to the C C(CN) 2 plane. The molecular structures of 4a, 4b and 4l also reveal a short Ni⋯C(4) separation, indicative of a Ni → C(4) donor–acceptor interaction. The electrochemistry of 4a shows aquasi reversible oxidation at ca. 1 V and complicated reduction processes. It is typical of most 4, but 4l is different in that it shows the same quasi reversible oxidation at ca. 1 V but two reversible reductions at −0.26 and −0.47 V (vs. [Fe(η 5-C 5Me 5) 2] +/0 0.0 V).

Synthesis and characterization of binuclear oxomolybdenum(V) and dioxomolybdenum(VI) O, O′-ditolyl dithiophosphate complexes. : Crystal structures of Mo 2O 3[S 2P(OC 6H 4Me- o) 2] 4, Mo 2O 3[S 2P(OC 6H 4Me- m) 2] 4 and MoO 2[S 2P(OC 6H 4Me- p) 2] 2

A series of binuclear oxomolybdenum(V) O, O′-ditolyl dithiophosphate complexes, Mo 2O 3[S 2P(OR) 2] 4 (R = o-, m-, p-C 6H 4Me) were synthesized by drop wise addition of aqueous solution of the ammonium salt of O, O′-ditolyl dithiophosphoric acid into an acidic solution of sodium molybdate with constant stirring to yield purple solids. Dioxomolybdenum(VI) O, O′-ditolyl dithiophosphate complexes, MoO 2[S 2P(OR) 2] 2 (R = o-, m-, p-C 6H 4Me and CH 2C 6H 5) were also synthesized by reducing Mo 2O 3[S 2P(OR) 2] 4 with OPPh 3 in benzene to yield yellow solids. These complexes were characterized by elemental analysis and IR, 1H and 31P NMR spectroscopy and, in three cases, by X-ray crystallography. In Mo 2O 3[S 2P(OC 6H 4Me- o) 2] 4 and Mo 2O 3[S 2P(OC 6H 4Me- m) 2] 4, the environment around each molybdenum atom can be described as the expected distorted octahedral, consisting of one terminal and one bridging oxygen along with the four chelating sulfur atoms of the dithio ligands, with one Mo–S distance being significantly longer than the other three. In MoO 2[S 2P(OC 6H 4Me- p) 2] 2 the geometry around the Mo atom is again distorted octahedral with two cis terminal oxygen atoms and two anisobidentate dithiophosphate ligands.

Poly(mercaptoimidazolyl)borate chemistry and the predominance of κ 3- S, S, H over κ 2- S, S or κ 3- S, S, S coordination modes: unexpected formation of square pyramidal Ni(II) complexes

The paramagnetic nickel(II) complexes [(dppe)Ni(L)]X (L=Bm R or Tm R) have been readily prepared from the appropriate 1,2-bis(diphenylphosphino)ethane adducts Ni(dppe)X 2 (X=Cl, Br) and the thallium(I) reagents Tl(Bm R) (R=Me, Bu t ) or Tl(Tm R) (R=Me, Bu t , p-Tol), and isolated as carmine to deep purple solids in 75–95% yield. X-ray diffraction studies of [(dppe)Ni(Bm Me)]Cl and [(dppe)Ni(Tm p-Tol )]Cl revealed the presence of a weak pseudo-axial Ni⋯H–B interaction and an overall square pyramidal geometry in each complex. As such, the cationic complexes [(dppe)Ni(L)] + are the first structurally characterized species having [NiP 2S 2H] cores and resemble a number of transient species that play a key role in the catalytic cycle of [NiFe] hydrogenases.

Synthesis and reactivity of novel ruthenium carbene catalysts. X-ray structures of [RuCl 2(CHSC 6H 5)(P iPr 3) 2] and [RuCl 2(CHCH 2CH 2- C, N-2-C 5H 4N)(P iPr 3)

Two novel classes of very air-stable ruthenium carbene complexes have been developed. The arylthio substituted ruthenium carbenes containing two bulky phosphines are deep purple solids, whereas the 2-pyridylethanyl substituted ruthenium carbene complexes contain only one bulky phosphine and are light-brown colored. One member of each class has been characterized with X-ray crystallography. The metathesis activity of these complexes has been investigated in the polymerization of dicyclopentadiene. Several excellent catalysts were identified. Desired geltimes and initiation temperatures could be easily tuned by changing the substitution pattern on the pendant ligand in the 2-pyridylethanyl substituted ruthenium carbenes.

Polymerization ofN-carbazolylacetylene by various transition metal catalysts and polymer properties

N-Carbazolylacetylene (CzA) was polymerized in the presence of various transition metal catalysts including WCl6, MoCl5, [Rh(NBD)Cl]2, and Fe(acac)3 to give polymers in good yields. The polymers produced with W catalysts were dark purple solids and soluble in organic solvents such as toluene, chloroform, etc. The highest weight-average molecular weight of poly(CzA) reached about 4 × 104. In the UV–visible spectrum in CHCl3, poly(CzA) exhibited an absorption maximum around 550 nm (εmax = 4.0 × 103 M−1 cm−1) and the cutoff wavelength was 740 nm, showing a large red shift compared with that of poly(phenylacetylene) [poly(PA)]. Poly(CzA) began to lose weight in TGA under air at 310°C, being thermally more stable than poly(PA) and poly[3-(N-carbazolyl)-1-propyne]. Poly(CzA) showed a third-order susceptibility of 18 × 10−12 esu, which was 2 orders larger than that of poly(PA). © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2489–2492, 1998

Polymerization of (o-Phenylphenyl)acetylene and (2,5-Di-tert-butylphenyl)-acetylene and Polymer Properties

o-(Phenylphenyl)acetylene and (2,5-di-tert-butylphenyl)acetylene polymerized with group 6 and 5 transition metal catalysts irrespective of the presence of the bulky ortho substituents. Both of the polymers were dark purple solids and insoluble in any organic solvents. The onset temperatures of weight loss of the polymers were 270°C and higher

ChemInform Abstract: Synthesis of New Phosphido‐Bridged Dinitrosyliron‐Containing Heteronuclear Metal Complexes.

AbstractThe new phosphido‐bridged complexes (III) and (V) are synthesized by bridge‐assisted reactions.

Synthesis of new phosphido-bridged dinitrosyliron-containing heteronuclear metal complexes

New phosphido-bridged, Fe(NO) 2-containing heteronuclear metal complexes have been synthesized by bridge-assisted reactions. Thus, deprotonation of Fe(NO) 2(PPh 2H) 2 with n-BuLi to Li 2[Fe(NO) 2(PPh 2) 2], followed by treatment with Cp 2MCl 2 (M = Zr, Ti), affords Cp 2M(μ-PPh 2) 2Fe(NO) 2 as air- stable, purple solids. Reaction of Fe(NO) 2(PPh 2H) 2 with cobaltocene in acetonitrile at reflux gives a dark green, air-sensitive solid that is provisionally formulated as Cp 2Co 2(μ-PPh 2) 2Fe 2(NO) 4. Various attempts to obtain a mixed carbonyl-nitrosyl complex, (CO) 3 Fe(μ-PPh 2) 2F e(NO) 2, proved unsuccessful. All new complexes were characterized by a combination of elemental analysis, FAB mass spectrometry, and IR and 1H and 31P NMR spectroscopy.

Übergangsmetall-carbin-komplexe XCVIII. N-Alkylierung eines ethylisocyanid-liganden am molybdän(0); Synthese und oxidationsreaktionen erster cyclopentadienyl-substituierter molybdän-diethylaminocarbin-komplexe

A large scale, high yield synthesis of the first cyclopentadienyl-substituted diethylaminocarbyne complexes of molybdenum has been developed starting from (η 5-C 5H 5)Mo(CO) 3I ( 1). In the first step of the synthetic procedure 1 is quantitatively transformed with EtNC in CH 2Cl 2 into an isomeric mixture of cis- and trans-(η 5-C 5H 5)Mo(CO) 2(EtNC)I ( 2a, 2b). The isomers 2a and 2b are then quantitatively reduced with sodium powder to the zerovalent molybdenum complex Na[(η 5-C 5H 5)Mo(CO) 2(EtNC)] ( 3). The ethylisocyanide ligand in 3 is susceptible to electrophilic attack at nitrogen. Thus reaction of 3 with Et 3OBF 4 gives as the major product, the low valent diethylaminocarbyne complex (η 5-C 5H 5)(CO) 2MoCNEt 2 ( 4). A minor product, the η 2-iminoacyl complex (η 5-C 5H 5)(CO) 2Mo[η 2-C(NEt)Et] ( 5), is also formed in this reaction via electrophilic attack on the electron rich metal center of 3. Compounds 4 and 5 are separated by column chromatography and isolated as yellow and red, microcrystalline solids in 60 and 8% yield respectively. Oxidative decarbonylation of 4 with I 2 and Br 2 leads to the high valent diethylaminocarbyne complexes (η 5-C 5H 5)(I) 2(CO)MoCNEt 2 ( 6) and (η 5-C 5H 5)(Br) 2-(CO)MoCNEt 2 ( 7), isolated as thermally stable, black and purple solids in quantitative yield. Composition and structure of the complexes 2a–7 were determined by total elemental analyses, IR, 1H NMR and 13C NMR spectra and the spectral data compared with the analogous tungsten compounds.

Studies of amidino-complexes of copper(I) and (II). Carboxylate analogues

Abstract Lithioamidines &{;R′N(Li)C(R)NR′; R = H, CH 3 , C 6 H 5 ; R′ = C 6 H 5 , p -CH 3 C 6 H 4 &}; react with anhydrous copper(II) chloride to form [Cu&{;R′NC(R)NR′&}; 2 ] n complexes, and with anhydrous copper(I) chloride to form [Cu&{;R′NC(R)NR′&};] m . The copper(II) complexes are diamagnetic, purple solids, which are air stable in the solid state but very air reactive in solution. Experimental data are consistent with a dimeric or more highly associated structure, and an X-ray structural determination shows [Cu&{;C 6 H 5 NC(C 6 H 5 )NC 6 H 5 &}; 2 ] 2 to be dimeric with four bridging amidino-groups and a short CuCu distance (2.46A). The copper(I) complexes are pale yellow solids, which in solution are subject to rapid aerial oxidation, especially in the presence of free amidines, and disproportionation to [Cu&{;R′NC(R)HR′&}; 2 ] n and copper metal. Differences in properties are noted between acetamidino-, benzamidino- and formamidino-complexes, the last complexes of copper(I) being most stable towards disproportionation. Cu&{;C 6 H 5 NC(CH 3 )NC 6 H 5 &}; 2 reacts with pyridine (Py) to form the copper(I) derivative Cu&{;C 6 H 5 NC(CH 3 )NC 6 H 5 &};. 2Py and with carbon disulphide to form Cu&{;C 6 H 5 NC(CH 3 )NC 6 H 5 &}; 2 .CS 2 which is reduced to form Cu&{;C 6 H 5 NC(CH 3 )NC 6 H 5 &};.CS 3 .

Complexes of uranium(III) with cyclic polyethers and with aromatic diamines

The complexes (UCl 3) 3(benzo-15-crown-5) 2, UCl 3(cylohexyl-15-crown-5), (UCl 3) 3(18-crown-6) 2 (UCl 3) 5(dibenzo-18-crown-6) 3, (UCl 3 5( cis-syn-cis- dicyclohexyl-18-crown) 3, UCl 3(1,10-phenanthroline) 2 and UCl 3(2,2″-bipyridyl) 2 have been prepared by zinc amalgam reduction of acetonitrile or acetonitrile/propionic acid solution of UCl 4 and the appropriate ligands. Reduction by sodium hydride was also used in one case. The complexes are brown, red, or purple solids which are oxidized in a air and are insoluble in those common organic solvent with which they do not react. Electronic spectra were obtained by reflectance in the range 350–1500 nm, and magnetic susceptibilities of the crown ether complexes at 298 K in the range 2.72–2.91 BM.

Alkylenebisdithiocarbamates of oxovanadium(IV), chromium(III), and manganese(II)

The ethylenebisdithiocarbamato and hexamethylenebisdithiocarbamato derivatives of oxovanadium(IV), chromium(III), and manganese(II) were synthesized and characterized using thermal, solubility, i.r., X-ray powder diffraction, and magnetic susceptibility measurements. Ethylenebis(dithiocarbamato)oxovanadium(IV) was a green, crystalline solid. Ethylenebisdithiocarbamatochromium(III) and hexamethylenebisdithiocarbamatochromium(III) were purple solids, insoluble in deionized water and common organic solvents. Ethylenebisdithiocarbamatomanganese(II) and hexamethylenebisdithiocarbamatomanganese(II) were yellow and light pink solids respectively. The magnetic susceptibility data for all five compounds could be fitted to the Weiss-Curie Law and had very small negative φ values suggesting weak antiferromagnetic interactions between the paramagnetic ions.

Cupric acetate complexes of pyridine and α-picoline

Complexes of the copper(II) salts of halogen-substituted acetates with the ligands pyridine and α-picoline have been prepared and studied, α-Picoline forms 1 : 1 and 2 : 1 complexes. With the exception of the trifluoracetate complex all 1 : 1 species are dimers. The 2 : 1 complexes are purple solids giving blue solutions in organic solvents (although a blue isomer of (CHCl2CO2)2Cu(α-pic)2 has been isolated). There are two arrangements of the α-picoline ligands which minimise interligand steric repulsions and which provide a possible explanation of the difference between solid and solution spectra of these complexes.