Dibenzo[b,e]phosphorin

Abstract

gas configuration of the Ni is exceeded by one electron. In an attempt to isolate (3) N O was lost and ( I ) was re-formed. The complexes ( I ) , Hal = C1 and Br, cannot indefinitely undergo reversible addition of N O because on prolonged action of NO they are converted into the oxidation products (Bu3PO)NiHalz 141. On reaction of (Bu3P)zNiJz 121 with NO the presence of the intermediates (2) and (3) cannot be demonstrated although, as the products (4) and (5) show, they probably represent steps in the reaction.if the reaction is carried out in hexane, Bu3PI2 is precipitated and can be isolated. The IR spectrum of the mixture of (4) and (5) contains three N O bands, of which one is assigned to (4) and the two others to the cis,trans isomersIs1 of (5). The analytical results and molecular weight of the mixture lie between those of ( 4 ) and (5).Chromatographic separation of (4) and (5) has not been accomplished because of the instability of (5). However, (5) is readily converted into ( 4 ) : if the mixture of (4) and (5) is treated with PBu3 the I bridges in (5) are broken and after removal of the excess of PBu3 in a high vacuum a t 90°C analytically pure (4) is obtained in 95 % yield (calculated on the (Bu3P)zNiIz ( I ) used). Iodonitrosylbis(tri-n-butylphosphine)nickel (4) is a violet compound that is liquid at room temperature and dissolves as the monomer in benzene. Its properties closely resemble those of the compounds [ ( C~H S )~P ]~N~( N O ) N O~ 141 and [ ( C~H~~)~P ] Z N~( N O ) I [5] which have been prepared by other methods.With phosphorus, as with other elements of Period 3, the tendency to formation ofp,-hybrid bonds is very slight. Only very recently have derivatives of tervalent phosphorus with coordination number 2 been prepared "1. We set ourselves the task of synthesizing dibenzo[b,e]phosphorin (9-phospha-anthracene) ( I ) , the phosphorus analogue of acridine, by removal of HCl from 5-chloro-5,10-dihydrodibenzo[b,e]phosphorin (2) [*I. We worked out two new methods of preparing (2) : a) A solution of the di-Grignard compound from bis(o-bromopheny1)methane (3) in tetrahydrofuran was added dropwise to a solution of dichlorodiethylaminophosphine (molar ratio ca. 1 : l ) in tetrahydrofuran at -8OOC. After evaporation of the solvent the residue was extracted with cyclohexane, filtered, and gaseous HC1 was passed into the filtrate. The crude product obtained on subsequent evaporation was sublimed and recrystallized from toluene; m.p.(after sublimation) [102][103][104][105][106][107][108][109]. To confirm its structure, the product (2). which is very sensitive to hydrolysis, was oxidized in sodium hydroxide solution to (4) [*I by hydrogen peroxide. ( 3 ) =+m NaOH 0 " ' OH ( 4 ) 61(2), 4 7% b) Analogously, interaction of the GIignard compound from (u-bromopheny1)phenylmethane (5) and chlorobis(diethy1amino)phosphine in tetrahydrofuran at -80 OC and treatment of the reaction mixture with cyclohexane and HCI as described in a) affords o-benzylphenyldichlorophosphine (6), b.p. 142-143 "j0.01 mm, n'," = 1.62...

CF3‐Inspired Synthesis of Air‐Tolerant 9‐Phosphaanthracenes that Feature Fluorescence and Crystalline Polymorphs

“…Figure highlights the UV/Vis spectra of 6 . The longest wavelength absorptions of 6 a ( λ =436 nm, ϵ =6710) and 6 b ( λ =438 nm, ϵ =3130) are comparable to II ( λ =429 nm) and III ( λ =432 nm, ϵ =7970), which is compatible to the energetic difference between the HOMO and LUMO mentioned above. TD‐DFT studies assigned absorptions at around λ =350 to 450 nm for 6 a and 6 b , which could be assigned as a HOMO‐to‐LUMO transition (Figure , top) .…”

“…Replacement of the sp 2 carbon atom(s) of polyaromatic hydrocarbon (PAH) molecules with heavier main‐group elements has been attractive because the heavier unsaturated double bonds induce intriguing π‐orbital (band) properties. After Märkl synthesized phosphabenzene (phosphorin, phosphinine) I as a phosphorus analogue of benzene in 1966, Bickelhaupt succeeded in generating 9‐phosphaanthracene II in 1967 (Figure a) . Introduction of a substituent at the 10 position was effective to improve the stability of 9‐phosphaanthracene, and characterization of III by using UV/Vis spectroscopy was thus achieved ,.…”

Diphosphahexaarenes as Highly Fluorescent and Stable Materials

“…In particular, linearly fused systems containing six‐membered phosphorus heterocycles date from 1967, when de Koe and Bickelhaupt reported the synthesis of the first conjugated anthracene‐like molecule, a scaffold that has recently received a great deal of attention . However, although arenes have been investigated for more than a century, large laterally fused systems containing six‐membered phosphorus heterocycles are virtually unknown.…”

Phosphinines as ligands in homogeneous catalysis: recent developments, concepts and perspectives

“…The mixed g 1 -g 6 binding mode in which the phosphinine behaves as an 8e − donor, has been found for metals in the center of the transition series, such as the manganese complex 23 depicted in Fig. 12.…”