chem_nor 0.5.5

Dart package that finds relevant chemical compounds using AI(Gemini) and PubChem. Use it to level up your chemistry knowledge and chat with your Ai chemist!

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.

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📖 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.

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🚀 Installation

Add the following to your pubspec.yaml:

dependencies:
  chem_nor: ^0.5.5

Then run:

dart pub get

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⚙️ 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:

Model	Identifier
Gemini 2.5 Flash Lite	GeminiModel.gemini_2_5_flash_lite.apiName
Gemini 2.5 Flash	GeminiModel.gemini_2_5_flash.apiName
Gemini 2.5 Pro	GeminiModel.gemini_2_5_pro.apiName
Gemini 3.0 Flash Preview	GeminiModel.gemini_3_flash_preview.apiName
Gemini 3.0 Pro Preview	GeminiModel.gemini_3_pro_preview.apiName

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

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🧬 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);
}

📄 View Text Output

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);

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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]

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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, ...]

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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, ...}

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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.

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🧰 Additional Modules

📐 Formula Parser

Parses chemical formulas into element maps.

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

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🏷️ IUPAC Naming

Generates IUPAC names from SMILES notation via PubChem.

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

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⚖️ 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

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🌡️ 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

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⚗️ Reaction Balancer

Automatically balances chemical equations.

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

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🛡️ 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}

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🔗 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

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📡 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

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🖼️ 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

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🔬 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');
  }
}

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📦 Module Summary

Module	Function	Description
🔬 ChemNOR Core	findListOfCompounds	AI + PubChem compound search
🔬 ChemNOR Core	findListOfCompoundsJSN	JSON-formatted compound search
🔬 ChemNOR Core	getSubstructureCids	PubChem substructure search
🔬 ChemNOR Core	getRelevantSmiles	AI-generated SMILES suggestions
🔬 ChemNOR Core	getCompoundProperties	PubChem compound property lookup
💬 Chemist	Chemist / chat	AI chemistry chatbot
📐 Formula Parser	parseFormula	Element map from formula
🏷️ IUPAC Naming	generateIupacName	SMILES → IUPAC name
⚖️ Molecular Weight	calculateMolecularWeight	Formula → molecular weight
🌡️ Periodic Table	PeriodicTable.getBySymbol	Element data lookup
⚗️ Reaction Balancer	ReactionBalancer.balance	Equation balancing
🛡️ Safety Data	getSafetyData	GHS hazard information
🔗 SMILES Parser	parseSmiles / isSmilesValid	SMILES structure analysis
📡 Spectroscopy	simulateProtonNmr / simulateIrSpectrum	Spectrum simulation
🖼️ Visualization	drawMolecule	PubChem structure image URL

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📄 License

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

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Made with ❤️ for the chemistry and Dart community.