ChemNOR

Chemical Heuristic Evaluation of Molecules Networking for Optimized Reactivity

A powerful Dart package that discovers relevant chemical compounds using Google Gemini AI and PubChem — your all-in-one chemistry toolkit.

📖 Overview

ChemNOR combines the power of Google Gemini AI with the vast PubChem chemical database to give you:

• 🔬 AI-driven compound discovery via SMILES pattern generation
• 💬 Conversational AI Chemist for chemistry Q&A
• 🧪 Formula parsing, IUPAC naming, and molecular weight calculation
• 📊 NMR, IR, and Mass spectroscopy simulation
• ⚖️ Automatic chemical equation balancing
• 🛡️ GHS safety data retrieval
• 🖼️ Molecular structure visualization

Note: A Google Cloud API Key is required for AI features.

🚀 Installation

Add the following to your pubspec.yaml:

dependencies:
  chem_nor: ^0.5.5

Then run:

dart pub get

⚙️ Initialization

Default Model (gemini-2.5-flash)

import 'package:chem_nor/chem_nor.dart';

final chemNor = ChemNOR(genAiApiKey: 'your-api-key');

Specifying a Model

final chemNor = ChemNOR(
  genAiApiKey: 'your-api-key',
  model: GeminiModel.gemini_2_5_pro.apiName,
);

note: use .apiName to get the api name of the model Available models:

// Print all available models
print(ChemNOR.availableModels);

🧬 Core Features

1. 🔍 Find Relevant Compounds

Finds chemical compounds matching an application description using AI-generated SMILES patterns and PubChem lookups.

import 'package:chem_nor/chem_nor.dart';

void main() async {
  final chemNor = ChemNOR(genAiApiKey: 'your-api-key');
  final results = await chemNor.findListOfCompounds('carboxylic acid compounds');
  print(results);
}

ChemNOR Compound Search Results
Generated at: 2025-02-06 13:55:01
Query SMILES patterns: C(=O)O, O=C(O)O, C(=O)C, C(=O)OC, C(=O)CC
====================================================
CID: 284
Name: formic acid
Molecular Formula: CH2O2
SMILES: C(=O)O
Hydrogen Bond Donor: 1
Hydrogen Bond Acceptor: 2
TPSA: 37.3
Complexity: 10.3
--------------------------------------------
CID: 767
Name: carbonic acid
Molecular Formula: CH2O3
SMILES: C(=O)(O)O
Hydrogen Bond Donor: 2
Hydrogen Bond Acceptor: 3
TPSA: 57.5
Complexity: 26.3
--------------------------------------------

For JSON output, use findListOfCompoundsJSN:

final results = await chemNor.findListOfCompoundsJSN('carboxylic acid compounds');
print(results);

2. 🔎 Substructure Search

Searches PubChem for compounds containing a given SMILES pattern and returns a list of matching compound IDs (CIDs).

final cids = await chemNor.getSubstructureCids('CC');
print(cids); // Output: [6324]

3. 🤖 AI SMILES Generation

Uses Gemini AI to suggest relevant SMILES patterns based on a chemical application description.

final smiles = await chemNor.getRelevantSmiles('carboxylic acid compounds');
print(smiles);
// Output: [C(=O)O, CC(=O)O, c1ccccc1C(=O)O, OC(=O)C(=O)O, ...]

4. 📋 Compound Properties

Fetches detailed compound properties from PubChem using a CID.

final props = await chemNor.getCompoundProperties('248');
print(props);
// Output: {cid: 248, name: carboxymethyl(trimethyl)ammonium, formula: C5H12NO2+, weight: 118.15, ...}

5. 💬 AI Chemist

Chat with an AI chemist specializing in chemistry topics. Uses Gemini AI with chemistry-focused context.

void main() async {
  final chemNor = ChemNOR(genAiApiKey: 'your-api-key');
  final response = await chemNor.Chemist(
    'Please educate me about carboxymethyl(trimethyl)ammonium'
  );
  print(response);
}

The Chemist method focuses on chemistry-related questions. Use the chat method for general-purpose conversation with optional chat history context.

🧰 Additional Modules

📐 Formula Parser

Parses chemical formulas into element maps.

final elements = parseFormula('H2SO4');
print(elements); // Output: {H: 2, S: 1, O: 4}

🏷️ IUPAC Naming

Generates IUPAC names from SMILES notation via PubChem.

final name = await generateIupacName('CCO');
print(name); // Output: ethanol

⚖️ Molecular Weight

Calculates molecular weight from a chemical formula.

final weight = calculateMolecularWeight('H2O');
print('Water molecular weight: $weight g/mol');
// Output: Water molecular weight: 18.01528 g/mol

🌡️ Periodic Table

Access detailed information about any element.

final oxygen = PeriodicTable.getBySymbol('O');
print('Oxygen: atomic number ${oxygen?.atomicNumber}, mass ${oxygen?.atomicMass}');
// Output: Oxygen: atomic number 8, mass 15.999

final metals = PeriodicTable.getByCategory('transition metal');
print('Number of transition metals: ${metals.length}');
// Output: Number of transition metals: 38

⚗️ Reaction Balancer

Automatically balances chemical equations.

final balanced = ReactionBalancer.balance('H2 + O2 = H2O');
print(balanced); // Output: 2H2 + O2 = 2H2O

🛡️ Safety Data (GHS)

Retrieves GHS chemical safety classifications and hazard codes.

final safetyInfo = await getSafetyData('acetone');
print('Signal word: ${safetyInfo['signal_word']}');
print('Hazard statements: ${safetyInfo['hazard_statements']}');
// Output:
// Signal word: Danger
// Hazard statements: {H225, H319, H336}

🔗 SMILES Parser

Analyzes SMILES notation to extract structural information.

final structure = parseSmiles('CCO');
print(structure);
// Output: {atomCounts: {C: 2, O: 1}, bondCounts: {single: 2, ...}, rings: 0, ...}

final isValid = isSmilesValid('C1=CC=CC=C1');
print('Is benzene SMILES valid? $isValid'); // Output: true

📡 Spectroscopy Simulation

Simulates NMR, IR, and Mass Spectrometry data from molecular structures.

// Proton NMR
final nmrData = await simulateProtonNmr('CCO');
print(nmrData['summary']);
// Output:
// ¹H NMR prediction for ethanol:
// δ 0.9 ppm (triplet, 3H) - Methyl group (-CH₃)
// δ 3.5 ppm (singlet (broad), 1H) - Hydroxyl group (-OH)
// δ 3.6 ppm (quartet, 2H) - CH₂ adjacent to oxygen

// IR Spectrum
final irData = await simulateIrSpectrum('CCO');
print('IR bands: ${irData['bands'].length}'); // Output: IR bands: 4

🖼️ Molecular Visualization

Generates a PubChem URL to visualize a compound from SMILES.

final url = drawMolecule('CCO');
print(url);
// Output: https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/smiles/CCO/PNG

🔬 Complete Example

Combine all modules for a comprehensive chemical analysis pipeline:

import 'package:chem_nor/chem_nor.dart';

void main() async {
  final chemNor = ChemNOR(genAiApiKey: 'your-api-key');

  // 1. Find compounds related to a query
  final compounds = await chemNor.findListOfCompounds('analgesic compounds');

  if (compounds.isNotEmpty) {
    final smiles = 'CC(=O)OC1=CC=CC=C1C(=O)O'; // Aspirin SMILES

    // 2. Get IUPAC name
    final name = await generateIupacName(smiles);

    // 3. Calculate molecular weight
    final formula = 'C9H8O4';
    final weight = calculateMolecularWeight(formula);

    // 4. Get GHS safety information
    final safety = await getSafetyData('aspirin');

    // 5. Simulate NMR spectrum
    final nmrData = await simulateProtonNmr(smiles);

    // 6. Generate visualization
    final visUrl = drawMolecule(smiles);

    // 7. Print comprehensive report
    print('Compound:          $name');
    print('Formula:           $formula');
    print('Molecular Weight:  $weight g/mol');
    print('Safety Signal:     ${safety['signal_word']}');
    print('NMR Summary:       ${nmrData['summary']}');
    print('Visualization:     $visUrl');
  }
}

📦 Module Summary

📄 License

This project is licensed under the MIT License — see the LICENSE file for details.