9750

8994

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شيمي فيزيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده شيمي

1393

شانزده،135ص.:مصور،جدول،نمودار﴿رنگي﴾

ص.ع.به فارسي و انگليسي

حسين فرخ پور

عليرضا نجفي چرمهيني

94/1/23

كيامرث اسكندري، عبدالحسين دباغ

شيمي

ID8994

1 2 محاسبات فركانسهاي ارتعاشي 71 1 1 محاسبات نوارهاي فوتوالكترون مولكولها 81 1 4 روش رسم طيفهاي فوتوالكترون 81 1 1 ارائه و تجزيه و تحليل نتايج 14 1 1 1 پپتيد حلقوي دوتايي سيس 14 1 1 2 پپتيد حلقوي سهتايي سيس 94 1 1 1 پپتيد حلقوي چهارتايي سيس 71 1 1 4 پپتيد حلقوي پنجتايي سيس 46 1 1 1 پپتيد حلقوي ششتايي سيس 17 1 1 6 پپتيد حلقوي هفتتايي سيس 18 1 1 7 پپتيد حلقوي هشتتايي سيس 18 1 1 8 پپتيد حلقوي نهتايي سيس 19 1 1 9 پپتيد حلقوي دهتايي سيس 19 1 1 11 پپتيد حلقوي پانزدهتايي سيس 111 1 1 11 مدلي براي ارائه اثر فوق مزدوج شدگي و همبستگي الكتروني بر ميزان انرژي يونش 611 1 1 21 نمودار بررسي تغييرات انرژي يونش بر حسب اندازه حلقه 911 1 6 تجزيه و تحليل پايداري نسبي صورتبنديها براساس تفكيك انرژي پايداري 111 1 6 1 بررسي تغييرات انرژي پپتيدهاي حلقوي پايدار و مسطح براساس متوسط انرژي هر واحد پپتيد ي 611 1 7 محاسبه تغييرات متوسط انرژي تشكيل پيوند صورتبنديهاي مسطح 121 1 8 بحث و نت يجه گي ري 121 مراجع 721 چكيده انگليسي 611 نه

116 Investigating the stability of different conformers of a number of nano ring peptides using decomposition energy method intermolecular hydrogen bonding hyperconjugation and electron correlation and Calculating their ionization energies to study their electronic structure properties Sara Sadat Karachi sara sadat k@yahoo com 2014 Department of Chemistry Isfahan University of Technology Isfahan 84156 83111 I R Iran Degree M Sc Language FarsiSupervisor D r Hossein Farrokhpour E mail Farrokhphossein@gmail com h farrokh@cc iut ac irAbstract Nanotubular cyclic peptides are an interesting class of compounds due to structural charac teristics and multitude of functions in living organisms Most of these compounds are bio logically active Due to their unique spatial conformations their simplicity and limitedconformational freedom cyclic peptides are widely used as model molecules for largerpeptides in chemistry biochemistry pharmaceutical chemistry and life sciences Structuredictates function but many intrinsic properties of biomolecules are masked by their envi ronment or by their interactions with it However structures and properties of biomole cules in the gas phase provide us with an understanding of their intrinsic properties in theabsence of the perturbations due to their interactions with their environment The demandsfor gas phase information arise from the anticipation that many biological phenomena canbe traced to the fundamental properties of molecular constituents One of the most im portant physicochemical properties of biomolecules is their ionization potentials Photoe lectron spectroscopy is a powerful technique that is mostly used for determining ionizationenergies of atoms and molecules The cyclic peptides selected in this work have cis con formation for the amide bond NH CO and their building blocks are glaycine amino ac ids The symmetry adapted cluster configuration interaction SAC CI methodology wasused for calculating several ionization energies for these compounds to study the electronicstructure of these compounds as a model for the other cyclic peptides The D95 D P ba sis set was employed for SAC CI calculations Natural bonding orbital NBO calculationswere used to assining the photoelectron bands of each molecule We studied also the roleof hyperconjugation steric effect intramolecular hydrogen bonding and electronic correla tions in determining the relative stability of different conformers of each size of cyclic pep tide in this work In addition the variation of the average energy of each peptide unit wasstudied versus the size of the cyclic peptide Keywords Ionization Energy Photoelectron Spectroscopy SAC CI Hyperconjugation Hydrogen Bonding

حسين فرخ پور

عليرضا نجفي چرمهيني

كيامرث اسكندري، عبدالحسين دباغ