Properties and Reactivity Patterns of AsP3: An Experimental and Computational Study of Group 15 Elemental Molecules

Abstract

Facile synthetic access to the isolable, thermally robust AsP3 molecule has allowed for a thorough study of its physical properties and reaction chemistry with a variety of transition-metal and organic fragments. The electronic properties of AsP3 in comparison with P4 are revealed by DFT and atoms in molecules (AIM) approaches and are discussed in relation to the observed electrochemical profiles and the phosphorus NMR properties of the two molecules. An investigation of the nucleus independent chemical shifts revealed that AsP3 retains spherical aromaticity. The thermodynamic properties of AsP3 and P4 are described. The reaction types explored in this study include the thermal decomposition of the AsP3 tetrahedron to its elements, the synthesis and structural characterization of [(AsP3)FeCp*(dppe)][BPh4] (dppe = 1,2-bis(diphenylphosphino)ethane), 1, selective single As-P bond cleavage reactions, including the synthesis and structural characterization of AsP3(P(N(iPr)2)N(SiMe3)2)2, 2, and activations of AsP3 by reactive early transition-metal fragments including Nb(H)(η2-tBu(H)C═NAr)(N[CH2tBu]Ar)2 and Mo(N[tBu]Ar)3 (Ar = 3,5-Me2C6H3). In the presence of reducing equivalents, AsP3 was found to allow access to [Na][E3Nb(ODipp)3] (Dipp = 2,6-diisopropylphenyl) complexes (E = As or P) which themselves allow access to mixtures of AsnP4−n (n = 1−4).