Cyano(triphenylsilyl)phosphanide as a Building Block for P,C,N Conjugated Molecules

Zwitterionic 2-Phosphaethene-thiolates [(LC)P=CS(LC/P)]+ as PCS Building Blocks (LC=NHC, LP=PR3)

The zwitterionic compounds [(LC)P=CS(LC/P)]+ (3+, LC=NHC, LP=PR3), featuring cationic substituents at the phosphorus and carbon atoms, are synthesized as their triflate salts at a multi-gram scale from the reaction of Lewis base adducts of CS2, namely LC/P-CS2 (4), with a combination of [(LCP)4][OTf]4 (1[OTf]4) and Ph3P. The feasibility of using 3+ as PCS building blocks is showcased in their reactions with representative electrophiles (MeOTf) and nucleophiles (MesMgBr, Ph3PCH2), leading to selective functionalization of the PCS core at the S- and P-terminus, respectively. Additionally, it is reported that 3+ can function as ambident nucleophiles with AgOTf (2 equivalents), affording unprecedented linear coordination polymer [Ag2(OTf)3-μ2:κP,κS-((LC)P=CS(PCy3))]+ (6 b), where the PCS moiety acts as a bridging ligand in transition metal complexes for the first time. Reduction of 3+ facilitates the cleavage of the P- and C-bound substituents leading to the formation of the [PCS]- anion. Moreover, cycloaddition reactions of 3+ with 1[OTf]4 are shown to selectively yield five- and eight-membered polyphosphorus heterocycles. Preliminary results suggest the possibility of activating the C-S bond in [(LC)P=CS(LC)]+, resulting in the formation of [(LC)P=C(LC)-P(LC)][OTf]2, 12[OTf]2, which may serve as a synthon for the PCP unit in future studies.

Cobalt-Mediated [3+1] Fragmentation of White Phosphorus: Access to Acylcyanophosphanides

Despite the accessibility of numerous transition metal polyphosphido complexes through transition-metal-mediated activation of white phosphorus, the targeted functionalization of Pn ligands to obtain functional monophosphorus species remains challenging. In this study, we introduce a new [3+1] fragmentation procedure for cyclo-P4 ligands, leading to the discovery of acylcyanophosphanides and -phosphines. Treatment of the complex [K(18c-6)][(Ar*BIAN)Co(η4 -P4 )] ([K(18c-6)]3, 18c-6=[18]crown-6, Ar*=2,6-dibenzhydryl-4-isopropylphenyl, BIAN=1,2-bis(arylimino)acenaphthene diimine) with acyl chlorides results in the formation of acylated tetraphosphido complexes [(Ar*BIAN)Co(η4 -P4 C(O)R)] (R=tBu, Cy, 1-Ad, Ph; 4 a-d). Subsequent reactions of 4 a-d with cyanide salts yield acylated cyanophosphanides [RC(O)PCN]- (9 a-d- ) and the cyclo-P3 cobaltate anion [(Ar*BIAN)Co(η3 -P3 )(CN)]- (8- ). Further reactions of 4 a-d with trimethylsilyl cyanide (Me3 SiCN) and isocyanides provide insight into a plausible mechanism of this [3+1] fragmentation reaction, as these reagents partially displace the P4 C(O)R ligand from the cobalt center. Several potential intermediates of the [3+1] fragmentation were characterized. Additionally, the introduction of a second acyl substituent was achieved by treating [K(18c-6)]9b with CyC(O)Cl, resulting in the first bis(acyl)monocyanophosphine (CyC(O))2 PCN (10).

An Isolable Radical Anion Featuring a 2-Center-3-Electron π-Bond without a Clearly Defined σ-Bond

Featuring an extra electron in the π* antibonding orbital, species with a 2-center-3-electron (2c3e) π bond without an underlying σ bond are scarcely known. Herein, we report the synthesis, isolation and characterization of a radical anion salt [K(18-C-6)]+ {[(HCNDipp)2 Si]2 P2 }⋅- (i.e. [K(18-C-6)]+ 3⋅- ) (18-C-6=18-crown-6, Dipp=2,6-diisopropylphenyl), in which 3⋅- features a perfectly planar Si2 P2 four-membered ring. This species represents the first example of a Si- and P-containing analog of a bicyclo[1.1.0]butane radical anion. The unusual bonding motif of 3⋅- was thoroughly investigated via X-ray diffraction crystallography, electron paramagnetic resonance spectroscopy (EPR), and calculations by density functional theory (DFT), which collectively unveiled the existence of a 2c3e π bond between the bridgehead P atoms and no clearly defined supporting P-P σ bond.

Direct synthesis of phosphorotrithioates from [TBA][P(SiCl3)2] and disulfides

Sulfur-containing organophosphorus molecules have played a pivotal role in organic synthesis, pharmaceutical pesticides and functional materials, thereby motivating researchers worldwide to establish S-P bonds from more environmentally friendly phosphorus sources. In this study, a novel method was developed for constructing S-P bonds, specifically by reacting the inorganic phosphorus derivative TBA[P(SiCl₃)₂] with sulfur-containing compounds under mild conditions. This method demonstrates the advantages of low energy consumption, mild reaction conditions and environmental friendliness. Moreover, this protocol-as a green synthesis method to replace the use of white phosphorus in the production of organophosphorus compounds (OPCs)-achieved the functional conversion of "inorganic phosphorus to organic phosphorus", in line with the national green development strategy.

Recent advances in the chemistry of the phosphaethynolate and arsaethynolate anions

Over the past decade, the reactivity of 2-phosphaethynolate (OCP^-), a heavier analogue of the cyanate anion, has been the subject of momentous interest in the field of modern organometallic chemistry. It is used as a precursor to novel phosphorus-containing heterocycles and as a ligand in decarbonylative processes, serving as a synthetic equivalent of a phosphinidene derivative. This perspective aims to describe advances in the reactivities of phosphaethynolate and arsaethynolate anions (OCE^-; E = P, As) with main-group element, transition metal, and f-block metal scaffolds. Further, the unique structures and bonding properties are discussed based on spectroscopic and theoretical studies.

Simple conversion of trisodium phosphide, Na3P, into silyl- and cyanophosphides and structure of a terminal silver phosphide

Reaction of trisodium phosphide (Na3P) with chlorosilanes allows for simple derivatization into silyl- and cyano-substituted phosphanide species which were compared to each other. The recently discovered cyano(triphenylsilyl)phosphanide shows unique coordination...