From Na(OCP) as a “P” transfer reagent, the radicals (NHC–P–E–P–NHC) (E = P, As) were synthesized and characterized as donor–acceptor adducts by EPR spectroscopy and DFT computations.

Carbon dioxide and two equivalents of Na(OCP) form, in an equilibrium reaction, a CO2 adduct of the composition Na2(P2C3O4). The anion of this salt, [O2C-P(CO)2P](2-), is built up by a four-membered 1,3-diphosphetane-2,4-dione ring and a carboxylate unit attached to one of the phosphorus atoms. A remarkable π-delocalization was observed within the OCPCO moiety. The stepwise reaction mechanism leading to Na2(P2C3O4) was investigated with quantum chemical calculations. Accompanied by the release of CO2, Na2(P2C3O4) reacts with both 2-iodopropane and 4,4',4''-trimethoxytriphenylmethyl chloride to form four-membered cyclic anions. For comparison the analogous reactions were performed with Na(OCP) instead of Na2(P2C3O4) and the results are discussed in detail.

The reactivity of Na(OCP) was investigated towards triorganyl compounds of the heavier group 14 elements (R3EX R = Ph or (i)Pr; E = Si, Ge, Sn, Pb; X = Cl, OTf). In the case of E = Si two constitutional isomers were formed and characterised in situ: R3Si-O-C[triple bond, length as m-dash]P is the kinetic and R3Si-P[double bond, length as m-dash]C[double bond, length as m-dash]O is the thermodynamic product, representing experimental evidence of the ambident character of the (OCP)(-) anion. Applying theoretical calculations and spectroscopic methods, the compound previously reported as (i)Pr3Si-O-C[triple bond, length as m-dash]P can now unambiguously be identified as (i)Pr3Si-P[double bond, length as m-dash]C[double bond, length as m-dash]O. The heavier analogues form exclusively the phosphaketene isomer R3E-P[double bond, length as m-dash]C[double bond, length as m-dash]O (E = Ge, Sn, Pb). DFT calculations were performed to gain deeper insight into the bonding and thermodynamic stability of these compounds.

Phosphorus-containing heterocycles have evolved from laboratory curiosities to functional components, such as ligands in catalytically active metal complexes or molecular constituents in electronic devices. The straightforward synthesis of functionalized heterocycles on a larger scale remains a challenge. Herein, we report the use of the phosphaethynolate (OCP)(-) anion as a building block for various sterically unprotected and functionalized hydroxy substituted phosphorus heterocycles. Because the resulting heterocycles are themselves anions, they are building blocks in their own right and allow further facile functionalization. This property may be of interest in coordination chemistry and material science.

The terminal rhenium(I) phosphaethynolate complex [Re(PCO)(CO)(2)(triphos)] has been prepared in a salt metathesis reaction from Na(OCP) and [Re(OTf)(CO)(2)(triphos)]. The analogous isocyanato complex [Re(NCO)(CO)(2)(triphos)] has been likewise prepared for comparison. The structure of both complexes was elucidated by X-ray diffraction studies. While the isocyanato complex is linear, the phosphaethynolate complex is strongly bent around the pnictogen center. Computations including natural bond orbital (NBO) theory, natural resonance theory (NRT), and natural population analysis (NPA) indicate that the isocyanato complex can be viewed as a classic Werner-type complex, that is, with an electrostatic interaction between the Re(I) and the NCO group. The phosphaethynolate complex [Re(P=C=O)(CO)(2)(triphos)] is best described as a metallaphosphaketene with a Re(I)-phosphorus bond of highly covalent character.

Carbon phosphides, C P , may have highly promising electronic, optical, and mechanical properties, but they are experimentally almost unexplored materials. Phosphaheteroallenes stabilized by N-heterocyclic carbenes undergo a one-electron reduction to yield compounds of the type (L) C P with diverse structures. The use of imidazolylidenes as ligands L give complexes with a central four-membered ring C P , while more electrophilic cyclic diamidocarbenes (DAC) give a compound with an acyclic π-conjugated CP-PC unit. Cyclic C P compounds are best described as non-Kekulé molecules that are stabilized by coordination to the NHC ligands NHC→(C P )←NHC. These species can be easily oxidized to give stable radical cations [(NHC) C P ] . The remarkably stable molecules with an acylic C P core are best described with electron-sharing bonds (DAC)=C=P-P=C=(DAC).

Cyanuric acid (C H N O ) is widely used as cross-linker in basic polymers (often in combination with other crosslinking agents like melamine) but also finds application in more sophisticated materials such as in supramolecular assemblies and molecular sheets. The unknown phosphorus analogue of cyanuric acid, P C (OH) , may become an equally useful building block for phosphorus-based polymers or materials which have unique properties. Herein we describe a straightforward synthesis of 2,4,6-tri(hydroxy)-1,3,5-triphosphinine and its derivatives P C (OR) which have been applied as strong π-acceptor η -ligands in piano stool Mo(CO) complexes.

The long‐sought carbene–bismuthinidene, (CAAC)Bi(Ph), has been synthesized. Notably, this represents both the first example of a carbene‐stabilized subvalent bismuth complex and the extension of the carbene‐pnictinidene concept to a non‐toxic metallic element (Bi). The bonding has been investigated by single‐crystal X‐ray diffraction studies and DFT calculations. This report also highlights the hitherto unknown reducing and ligand transfer capability of a beryllium(0) complex.