OPTIMASI SIFAT INHIBITOR KOROSI SENYAWA THIAAMIDA-PIRAZOLINDOL BERDASARKAN TEORI FUNGSIONAL KERAPATAN - Saprini Hamdiani; Jannatin Arduha; Agus Abhi Purwoko; Saprizal Hadisaputra (Jurnal Pijar Mipa, 2016)
Abstrak. Sifat inhibitor korosi senyawa turunan thiaamida-pirazolindol (TP) telah dikaji menggunakan teori fungsional kerapatan pada tingkatan teori B3LYP/6-31G(d). Pengaruh gugus substitusi pendonor dan penarik elektron (NH2, SH, CHCH2, CH3, OH, CHO, COOH, F, NO2) terhadap efisiensi anti korosi senyawa thiaamida-pirazolindol juga dihitung. Parameter kuantum untuk senyawa anti korosi seperti energi orbital (EHOMO dan ELUMO), potensial ionisasi (I), afinitas elektron (A) dan elektronegativitas (Ãâ¡) memiliki hubungan yang linier dengan efisiensi anti korosi (IE%) senyawa turunan thiaamida-pirazolindol. Gugus pendonor elektron meningkatkan nilai IE%. Urutan kenaikan IE% adalah NO2 < CHO < COOH < F < CHCH2 < OH < CH3 < NH2. Penambahan gugus pendonor elektron amina (NH2) meningkatkan IE% hingga 98,76 % dibandingkan IE% thiaamida-pirazolindol murni 90,80 %. Penambahan gugus penarik elektron menurunkan IE% hingga mencapai 82,82 %. Kajian teoritis ini akan berkontribusi besar dalam mendesain dan sintesis senyawa inhibitor organik dengan efisiensi inhibitor tinggi.Kata kunci: inhibitor korosi, teori fungsional kerapatan, thiaamida-pirazolindolAbstract. Corrosion inhibitor properties of thiamide pyrazolindole and its derivatives has been elucidated by means of density functional theory (DFT) at B3LYP/6-31G(d) level of theory. Effect of electron donating and withdrawing groups such as NH2, SH, CHCH2, CH3, OH, CHO, COOH, F and NO2 on the corrosion inhibitor of thiamide pyrazolindole derivatives also have been studied. The quantum chemical parameters such as the frontier orbital energies (EHOMO), ionization potential (I), electron affinity (A) and electronegativity (Ãâ¡) are closely related to the corrosion inhibition efficiency (IE%) of thiamide pyrazolindole derivatives. The presence of electron donating groups increases IE% values meanwhile electron withdrawing groups reduce IE% values. The enhancement of IE% follows NO2 < CHO < COOH < SH < F < CH3 < CHCH2 < OH < NH2. Electron donating NH2 group gives 98,76 % of IE%, pure thiamide pyrazolindol IE% = 90,80 %. In contrast, electron withdrawing NO2 group gives IE% only 82,82 %. This theoretical study would have a significant contribution in designing high-efficiency organic corrosion inhibitors.Keywords: corrosion inhibitors, density functional theory, thiamide pyrazolindol