Elektronik Reaktivite İndeksi (ERI): Deniz Çeliğine Yönelik Yeşil Korozyon İnhibitörlerinin Taranması İçin Heuristik Bir Bileşik Tanımlayıcı

Abstract

Organik korozyon inhibitörlerinin kuantum-kimyasal taramalarında moleküller çoğunlukla ya E_HOMO değerine ya da HOMO–LUMO enerji aralığına, ΔE, göre sıralanmaktadır. Bu ayrım kullanışlı olmakla birlikte kimyasal açıdan eksiktir. Çelik yüzeyine adsorpsiyon, hem erişilebilir bir dolu sınır orbitalini hem de arayüzeydeki yük yeniden dağılımına uyum sağlayabilecek yeterli elektronik yumuşaklığı gerektirir. Bu birleşik gereksinimi yakalamak amacıyla, Elektronik Reaktivite İndeksi, ERI = EHOMO / ΔE, deniz çeliğine yönelik yeşil inhibitör adayları için heuristik bir ilk-aşama tarama tanımlayıcısı olarak tanımlanmıştır. CDFT açısından ERI, (1/2) EHOMO × S ile ölçeklenir; burada S global yumuşaklığı ifade eder. Bu çalışmada kullanılan negatif orbital enerji gösteriminde, daha negatif ERI değerleri erişilebilir dolu orbitalleri daha dar enerji aralıklarıyla birleştiren molekülleri işaret eder. Beş yapısal sınıftan yirmi iki organik molekül, örtük sulu çözücü modeliyle, epsilon = 78.4, PM7 yöntemi kullanılarak değerlendirilmiştir. Kuersetin en güçlü ERI yanıtını vermiştir (-1.165); onu luteolin ve kafeik asit izlemiştir. En yüksek sıralı bölgeye, genişletilmiş pi-delokalizasyonu ve oksijen merkezli donör bölgeleri ile uyumlu olarak konjuge flavonoidler ve fenolikler hâkim olmuştur. Literatürde bildirilen inhibisyon davranışları aynı genel kimyasal eğilimi izlemiştir; ancak bu karşılaştırma istatistiksel doğrulama sağlamamaktadır. Seçilen beş yüksek sıralı aday için yapılan SwissADME profillemesi Lipinski beş kuralı ihlali göstermemiştir. ERI, klorür ortamında yapılacak elektrokimyasal testlerden önce düşük maliyetli bir elektronik filtre olarak değerlendirilmelidir.

Keywords

• Elektronik Reaktivite İndeksi (ERI)
• Yeşil korozyon inhibitörleri
• Kuantum kimyası
• Yapı–reaktivite ilişkileri
• Deniz çeliği

Electronic Reactivity Index (ERI): A Heuristic Composite Descriptor for Screening Green Corrosion Inhibitors for Marine Steel

Abstract

Most quantum-chemical screens of organic corrosion inhibitors rank molecules from either EHOMO or the HOMO–LUMO gap, ΔE. That split is convenient, but chemically incomplete. Adsorption on steel requires both an accessible occupied frontier orbital and enough electronic softness to accommodate interfacial charge redistribution. To capture this coupled requirement, we define the Electronic Reactivity Index, ERI = EHOMO / ΔE, as a heuristic first-pass descriptor for green inhibitor candidates for marine steel. In CDFT terms, ERI scales with (1/2) EHOMO × S, where S is global softness. With the negative orbital-energy convention used here, more negative ERI values mark molecules that combine accessible occupied orbitals with narrower gaps. Twenty-two organic molecules from five structural classes were evaluated using PM7 with implicit aqueous solvation, epsilon = 78.4. Quercetin gave the strongest ERI response (-1.165), followed by luteolin and caffeic acid. The highest-ranked region was dominated by conjugated flavonoids and phenolics, consistent with extended pi-delocalisation and oxygen-centred donor sites. Literature-reported inhibition behaviour followed the same broad chemical trend, although it does not provide statistical validation. SwissADME profiling of five selected high-ranked candidates showed no Lipinski rule-of-five violations. ERI is best viewed as a low-cost electronic filter before chloride-media electrochemical testing.

Keywords

• Electronic Reactivity Index (ERI)
• Green corrosion inhibitors
• Quantum chemistry
• Structure-reactivity relationships
• Marine steel

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