Question

Find the number of moles of \(\mathrm{CH}_{3} \mathrm{MgCl}\) consumed by 1 mole of Nc1cccc(N)c1

Short answer

In conclusion, the number of moles of \(\mathrm{CH_3MgCl}\) consumed by 1 mole of pyridazine is 1 mole, since the stoichiometry of the reaction is 1:1.

Step-by-step solution

Identify the molecules

Before solving the problem, let's identify the molecules involved in the reaction. The given molecule with the SMILES notation Nc1cccc(N)c1 represents "pyridazine", which is an aromatic heterocyclic compound containing two nitrogen atoms. On the other hand, CH3MgCl is a Grignard reagent with the formula written as \(\mathrm{CH_3MgCl}\).

Understand the reaction mechanism

Pyridazine has two nitrogen atoms, and the most common reaction with Grignard reagents involves addition to one of these nitrogen atoms. The Grignard reagent is a strong nucleophile and forms a new carbon-nitrogen bond upon reaction. In the case of pyridazine, the less electron-rich nitrogen (substituted nitrogen) should be more reactive towards Grignard reagents. This is due to the electron-donating effect of the nitrogen, which makes the adjacent nitrogen less electron-rich and therefore more susceptible to nucleophilic attack. Thus, the reaction occurs as follows: Pyridazine (Nc1cccc(N)c1) + CH3MgCl -> N-CH3 substituted pyridazine + MgCl2

Determine the stoichiometry of the reaction

Now that we understand the reaction mechanism, we can determine the stoichiometry of the reaction. Based on the reaction equation, 1 mole of pyridazine reacts with 1 mole of CH3MgCl to form 1 mole of N-CH3 substituted pyridazine and 1 mole of MgCl2. Therefore, the stoichiometry of the reaction is 1:1.

Calculate the number of moles of CH3MgCl required

Since the stoichiometry of the reaction is 1:1, it means that for every 1 mole of pyridazine, we will need an equal amount of CH3MgCl to react with it. Therefore, 1 mole of pyridazine requires 1 mole of CH3MgCl to completely react. In conclusion, the number of moles of \(\mathrm{CH_3MgCl}\) consumed by 1 mole of pyridazine is 1 mole.

Key concepts

Pyridazine

Pyridazine is an interesting aromatic heterocyclic compound that contains two nitrogen atoms within its six-membered ring structure. It is important to distinguish it from other similar compounds like pyridine, which contains only one nitrogen atom. In pyridazine, the nitrogen atoms play a crucial role, making the molecule highly polar and reactive. These nitrogen atoms can act as sites for nucleophilic attacks in chemical reactions. Pyridazine is stable owing to its aromaticity, which results from the delocalization of electrons over the ring. This electron delocalization constrains addition reactions unless they provide substantial thermodynamic advantage. Understanding the structure of pyridazine aids in predicting its chemical behavior, especially in reactions with nucleophiles like Grignard reagents.

Reaction Mechanism

The reaction between pyridazine and a Grignard reagent, such as \( \text{CH}_3\text{MgCl} \), is a fascinating example of a nucleophilic addition reaction. Grignard reagents are powerful nucleophiles due to their organomagnesium compound nature. In the specific case of pyridazine reacting with a Grignard reagent, the nucleophile targets one of the nitrogen atoms. These reactions usually lead to the formation of a new carbon-nitrogen bond, resulting in a substituted pyridazine. A typical reaction mechanism involves the nucleophilic carbon of the Grignard reagent attacking the less electron-rich nitrogen of the pyridazine ring. This results in the creation of a new bond while also yielding magnesium chloride as a byproduct. The mechanism highlights how electron-rich regions can deter nucleophilic attacks, steering reactions towards more electron-deficient sites.

Stoichiometry

Stoichiometry is a fundamental concept in chemistry that helps us understand how reactants relate in a chemical reaction. In the case of the reaction between pyridazine and \( \text{CH}_3\text{MgCl} \), stoichiometry tells us that for every mole of pyridazine, one mole of \( \text{CH}_3\text{MgCl} \) is required. This 1:1 ratio is derived from the balanced chemical equation that illustrates the reaction mechanism. Such stoichiometric calculations are crucial for determining how much of each reactant is necessary to ensure complete consumption. By understanding this, chemists can efficiently plan and execute reactions without excess waste of valuable reagents. Accurate stoichiometric calculations are vital in industrial chemistry where the scaling of reactions matters significantly.

Nucleophilic Attack

Nucleophilic attack is a key concept in many chemical reactions, including the reaction of pyridazine with Grignard reagents. A nucleophile is a species rich in electrons and carries a partial negative charge, allowing it to donate electrons to electrophilic sites. In a nucleophilic attack, this electron-rich entity aims at a positively charged or electron-deficient site within the molecule. In the pyridazine- \(\text{CH}_3\text{MgCl}\) reaction, the Grignard reagent, which acts as a nucleophile, targets the nitrogen in pyridazine. The attack mainly occurs on the nitrogen atom that is less electron-rich, facilitating the formation of a new bond. Successful nucleophilic attacks often require the nucleophile to overcome steric and electronic barriers, dictating the kinetics and outcome of the reaction. The concept of nucleophilic attack is central to understanding reactivity patterns in organic chemistry.