Phosphorus Copies of PPV:  π-Conjugated Polymers and Molecules Composed of Alternating Phenylene and Phosphaalkene Moieties

Abstract

A new class of pi-conjugated macromolecule, poly(p-phenylenephosphaalkene) (PPP), is reported. PPPs are phosphorus analogues of the important electronic material poly(p-phenylenevinylene) (PPV) where P=C rather than C=C bonds space phenylene moieties. Specifically, PPPs [-C(6)R(4)-P=C(OSiMe(3))-C(6)R'(4)-C(OSiMe(3))=P-](n)() (1: R = H, R' = Me; 11: R = Me, R' = H) were synthesized by utilizing the Becker reaction of a bifunctional silylphosphine, 1,4-C(6)R(4)[P(SiMe(3))(2)](2), and diacid chloride 1,4-C(6)R'(4)[COCl](2). Several model compounds for PPP are reported. Namely, mono(phosphaalkene)s R-P=C(OSiMe(3))-R' (4: R = Ph, R' = Mes; 7: R = Mes, R' = Ph), C-centered bis(phosphaalkene)s R-P=C(OSiMe(3))-C(6)R'(4)-C(OSiMe(3))=P-R (5: R = Ph, R' = Me; 8: R = Mes, R' = H), and P-centered bis(phosphaalkene)s R-C(OSiMe(3))=P-C(6)R'(4)-P=C(OSiMe(3))-R (6: R = Mes, R' = H; 10: R = Ph, R' = Me). Remarkably, selective Z-isomer formation (i.e., trans arylene moieties) is observed for PPPs when bulky P-substituents are employed while E/Z-mixtures are otherwise obtained. X-ray crystal structures of Z-7, Z,Z-8, and Z,Z-10 suggest moderate pi-conjugation. The twist angles between the P=C plane and unsubstituted arenes are 16 degrees -26 degrees , while those between the P=C plane and methyl-substituted arenes are 59 degrees -67 degrees . The colored PPPs and their model compounds were studied by UV/vis spectroscopy, and the results are consistent with extended pi-conjugation. Specifically, weakly emissive polymer E/Z-1 (lambda(max) = 338 nm) shows a red shift in its absorbance from model E/Z-4 (lambda(max) = 310 nm), while a much larger red shift is observed for Z-11 (lambda(max) = 394 nm) over Z-7 (lambda(max) = 324 nm).

Acetylene‐Expanded Dendralene Segments with Exotopic Phosphaalkene Units

“…The reaction is accompanied by a color change from reddish-brown to reddish-yellow, and the appearance of a new yellow spot on the TLC plates. NMR spectroscopic analysis reveals the formation of two products with 31 P chemical shifts at d = 341.6 (4 a) and 342.8 ppm (4 b). Neither of the products contains TMS groups, nor 1 H NMR spectroscopic signals in the diagnostic acetylene region that point towards the formation of two isomers of 4.…”

“…[1,2,11,23] The introduction of heteroatoms in the form of higher alkenes as surrogates of traditional alkenes has been explored to a much lesser extent, despite the advantages in terms of lower HOMO-LUMO gaps and polarizability that are offered by this strategy. [24][25][26] The first oligo-phenylethylene analogues that feature disilenes, [27][28][29] phosphaalkenes, [30,31] and diphosphenes [32,33] instead of classical C=C bonds have emerged in the literature only recently. The reason for the sporadic presence of such structures is caused by a shortage of synthetic protocols that allow for their preparation as well as the general instability of higher element p bonds.…”

Group 6 metal carbonyl complexes of a family of bulky phosphines: spectroscopic and structural studies of chromium(0)-, molybdenum(0)- and tungsten(0)-pentacarbonylsilylphosphines

“…pentane leaving a pale yellow/brown solid behind. The solid was re-dissolved in hexane and X-ray quality crystals of Cr(PhP{TMS} 2 )(CO) 5 (4), Mo(PhP{TMS} 2 ) (CO) 5 (5) and W(PhP{TMS} 2 ) (CO) 5 (6) were grown from slow evaporation of the solvent in an inert atmosphere glove box. (7), Mo (8), W (9) A solution of M(CO) 5 THF, M ¼ Cr, Mo and W was prepared by irradiating 1.1 mmol of the respective hexacarbonyl in 50 mL of THF using a high-pressure mercury lamp in 1-h increments with degassing for 3-4 h. The HP(TMS) 2 was generated by adding 0.041 mL (1.0 mmol) of dry, degassed CH 3 OH to 0.29 mL (1.0 mmol) of P(TMS) 3 in 2.5 mL of THF.…”

“…For example P(TMS) 3 has been recently reported for use in the synthesis of new wide-bite-angle diphosphines, indium-phosphide nanocrystals and chiral phosphabarrelene ligands [2][3][4]. The use of PhP(TMS) 2 is reported in the diasteroselective addition of silylphosphines to chiral aldehydes and preparation of heteronuclear pconjugated polymers [5,6]. Finally, HP(TMS) 2 has appeared in the literature for use in the synthesis of unique aluminum-phosphorus bonded compounds and functionalized alkylidenephosphines [7,8].…”

Synthesis and low-temperature dehydrating imidation polymerization of 1,4-dihydro-1,4-diarsininetetracarboxylic acid dianhydride

“…[1][2][3][4][5] For example, heteroatom-containing poly(phenylene)s, such as poly(phenyleneoxide), poly(phenylenesulfide) and polyaniline, are industrially important as engineering plastics and electrical materials. Heteroaromatic polymers, such as polythiophene and polypyrrole, have also been intensively investigated and widely applied.…”