Electrophilic terminal phosphinidene complexes [Ar-Ar-P-W(CO)₅] (Ar-Ar: biaryl or an analogue thereof) undergo a spontaneous insertion of the phosphorus atom into the vicinal CH bonds to give annelated phospholes. Twelve examples are described, including biphenyl, thienyl, pyrrolyl, and benzofuryl groups as biaryl moieties. The activation energy of the insertion reaction is quite low (about 2 kcal mol⁻¹).

Electrophilic terminal phosphinidene complexes [Ar-Ar-P-W(CO)₅] (Ar-Ar: biaryl or an analogue thereof) undergo a spontaneous insertion of the phosphorus atom into the vicinal CH bonds to give annelated phospholes. Twelve examples are described, including biphenyl, thienyl, pyrrolyl, and benzofuryl groups as biaryl moieties. The activation energy of the insertion reaction is quite low (about 2 kcal mol⁻¹).

The reactions of BX₃ (X = Cl, Br) with 7-R-7-phosphanorbornadiene–M(CO)₅ (M = Mo, W) complexes (1) yields products 2 and 4 in which the RP–M(CO)₅ unit is inserted into one of the carboxyl units of the phthalic derivative as a result of the collapse of the bridge. When X = Br, 4 cyclizes to give new six-membered heterocycles 5 with quasiplanar structures. When treated by an excess of BBr₃, heterocycles 5 undergo ring contraction to afford five-membered oxocyclic products 6.

The discovery and molecular engineering of novel electroluminescent materials is still a challenge in optoelectronics. In this work, the development of new π-conjugated oligomers incorporating a dihydrophosphete skeleton is reported. Variation of the substitution pattern of 1,2-dihydrophosphete derivatives and chemical modification of their P atoms afford thermally stable derivatives, which are suitable emitters to construct organic light-emitting diodes (OLEDs). The optical and electrochemical properties of these new P-based oligomers have been investigated in detail and are supported by DFT calculations. The OLED devices exhibit good performance and current-independent CIE coordinates.

A DFT study suggests that the conversion of arsolylcarbenes into arsenines as described by Märkl proceeds via arsabenzvalenes. A similar conversion does not work with phospholylcarbenes. However, we have found that, in some cases, 1-diazoalkylphosphole sulfides are converted into phosphinine sulfides whose in situ reduction by triphenylphosphite affords the dicoordinate phosphinines.

The reaction of tributylphosphane with a 7-(2′-formyl-2-biphenylyl)phosphanorbornadiene P-W(CO)₅ complex leads to the 5-phosphaphenanthrene P-W(CO)₅ complex via an intramolecular phospha-Wittig condensation. This complex is stable enough for detection by ³¹P NMR spectroscopy but cannot be isolated due to its high reactivity. It is trapped by addition of MeOH or cycloaddition with 2,3-dimethylbutadiene or a nitrileimine. The adducts were characterized by X-ray crystal structure analysis.

Correcting an earlier report, the reaction of 1-phenyl-3,4-dimethylphosphole (1a) with an excess amount of dimethyl acetylenedicarboxylate (DMAD) at room temperature affords the stable cyclopentadienylidenephosphorane 3a resulting from unexpected deoxygenation of initially formed [phosphole + 2DMAD] adduct 2a by the starting phosphole. The identity of 3a was established by X-ray crystal structure analysis. DFT calculations on a model [1+2] adduct similar to 2a shows a bent allenic structure and an ambident reactivity for the terminal carbon of the (DMAD)₂ chain. Cyclopentadienylidenephosphorane 3b is also obtained with 1-benzylphosphole 1b. With 1-stannylphosphole 1c, a 1:3 adduct with a seven-membered ring (i.e., 5) is obtained. It was also characterized by X-ray crystal structure analysis. Finally, with 1-benzyl-2-benzoylphosphole 1d, the P lone pair has lost its nucleophilicity and a [4+2] cycloaddition takes place with the dienol tautomer of the unsaturated ketone to give phosphindole 6, also characterized by X-ray.