Improved Synthesis of Asymmetrical Substituted 1H-1,2,4-Diazaphospholes

Hydrazone Phosphaketene as a Synthetic Platform To Obtain Three Classes of 1,2,4-Diazaphosphol Derivatives by Switchable Chemoselectivity Strategies

We introduce switchable chemoselectivity strategies based on the hydrazone phosphaketene intermediate to synthesize three classes of 1,2,4-diazaphosphol derivatives. First, the five-membered heterocyclic P and O anion intermediates acted as nucleophilic agents in the selective construction of C-P and C-O bonds. Second, the phosphinidene served as a phosphorus synthon, allowing for the formation of C-P and C-N bonds. Finally, a stepwise mechanism, supported by DFT calculations, was invoked to explain the reaction selectivity.

Synthesis and properties of 1,2,3-diazapnictol-5-yl substituted ferrocenes

A series of new ferrocene derivatives bearing 1,2,3-diazapnictolyl substituents were synthesised and their spectroscopic and electrochemical properties were studied.

Synthesis and coordination properties of new σ2,λ3-P/N switchable chelators based on [1,2,3]-diazaphosphole

New ligands with σ²,λ³-P/N switching ability were synthesised and their coordination properties toward transition metals were studied.

1,2,4-Diazaphospholide complexes of lanthanum(iii), cerium(iii), neodymium(iii), praseodymium(iii), and samarium(iii): synthesis, X-ray structural characterization, and magnetic susceptibility studies

A few heteroleptic, charge-separated heterobimetallic, and polymeric alkali metalate complexes of 1,2,4-diazaphospholide lanthanum(iii), cerium(iii), neodymium(iii), praseodymium(iii), and samarium(iii) were simply prepared via the metathesis reaction of MCl3 (THF)m (m = 1-2) and K[3,5-R2dp] ([3,5-R2dp](-) = 3,5-di-substituent-1,2,4-diazaphospholide; R = tBu, Ph) in a varied ratio (1 : 3, 1 : 4, and 1 : 5, respectively) at room temperature in tetrahydrofuran. All the complexes were fully characterized by (1)H, (13)C{(1)H}, (31)P{(1)H}, IR, and X-ray single crystal diffraction analysis despite their paramagnetism (excluding La(iii) complexes). The structures of the complexes were found to feature varied coordination modes. The magnetic properties of several compounds were studied by magnetic susceptibility, and the complexes presented the magnetic moments close to or lower than the theoretical values for the free ions in the trivalent oxidation states (Pr(3+), Nd(3+)).

Chromium(III) complexes with 1,2,4-diazaphospholide and 2,6-bis(N-1,2,4-diazaphosphol-1-yl) pyridine ligands: synthesis, X-ray structural characterization, EPR spectroscopy analysis, and magnetic susceptibility studies

Three chromium(III) 1,2,4-diazaphospholide complexes were prepared: 3,5-di-tert-butyl-1,2,4-diazaphospholide chromium(III) dichloride [(η 2-3,5-tBu2dp)Cr(THF)2Cl2] (1), 3,5-di-phenyl-1,2,4-diazaphospholide chromium(III) dichloride [(η 2-3,5-Ph2dp)Cr(THF)2Cl2] (2), and 2,6-bis(N-1,2,4-diazaphosphol-1-yl)pyridine chromium(III) trichloride {[2,6-bis(N-1,2,4-diazaphosphol-1-yl)pyridine]CrCl3} (3). X-ray diffraction analysis has shown that these six-coordinate complexes each have a pseudo-octahedral configuration. Electron paramagnetic resonance (EPR) spectroscopy data for complex 1 for the paramagnetic S = 3/2 system (d 3 electron configuration) confirm a Cr(III) center in the octahedral coordination environment. The magnetic susceptibility of complex 1 followed the Curie–Weiss law well between 25 and 300 K. The magnetic moment of 1 was found to be close to the spin-only magnetic moment expected for three unpaired electrons (3.87 μB).

1-Methyl-3,5-diphenyl-1H-1,2,4-diazaphosphole

In the titleN-substituted 1,2,4-diazaphosphole, C15H13N2P, the phenyl rings make dihedral angles of 29.8 (3) and 55.9 (3)° with the 1,2,4-diazaphosphole ring. In the crystal, no significant intermolecular interactions are present.