Divalent N(I) compounds with two lone pairs on nitrogen.

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Main Group Chemistry

Background:

• Divalent main group elements in low oxidation states, such as C(0) and Si(0), are known.
• Previous experimental evidence for Si(0) and P(I) states prompted exploration of similar nitrogen compounds.

Purpose of the Study:

• To search for and identify novel divalent nitrogen N(I) compounds.
• To characterize the electronic structure and reactivity of these newly discovered nitrogen systems.

Main Methods:

• Synthesis and identification of biguanide derivatives as divalent nitrogen N(I) compounds.
• Quantum chemical analysis to determine structural details, molecular orbitals, and charge distribution.
• Comparative analysis of electronic structure and reactivity with divalent C(0) systems.

Main Results:

• Identification of ::N(←L)(2)(⊕) systems with bicoordinated nitrogen in the N(I) formal oxidation state, particularly in protonated biguanide derivatives.
• Characterization of these compounds by two lone pairs on the central nitrogen, analogous to divalent C(0) compounds.
• Detailed analysis of electronic structure, including molecular orbitals, atomic charges, and reactivity towards Lewis acids.

Conclusions:

• The discovery of divalent nitrogen N(I) systems represents a new bonding environment for nitrogen, distinct from nitrenium ions.
• These novel compounds exhibit unique electronic properties and reactivity patterns.
• The findings expand the scope of low-valent main group chemistry.