求助：gaussian模拟金属催化甲酸与甲醇酯化反应过程，为什么不反应呢？

fuhua · 发表于 Post on 2024-9-10 18:14:26

各位老师好，最近模拟了一个甲酸与甲醇酯化反应的过程。第一步为金属节点与羰基氧原子配位，C=O键变为C-O，氧夺取C原子的电子，C变为C+离子，随后甲醇的氧原子进攻C+离子。形成产物。但是就是这一步骤始终找不到过渡态，请问一下是什么原因。是位置摆放得不合理还是参数设置有问题呢？为了快速找到过渡态，用了小基组试的。金属为Ti原子，可以与氧原子配位。结果就是下图的结构，产生不了虚频。

输入文件如下
%nprocshared=14
%mem=3GB
%chk=C:\Users\fuhua\Desktop\ts12.chk
# opt=(calcfc,ts,noeigen) freq upm6 nosymm

ts

0 1
Ti             -1 -3.63187100 -1.95280700 -0.00006600
O             -1 -5.57265800 -1.94819400 -0.00004400
Ti             -1 -0.77603300 -4.04976900 -0.00006600
O             -1 -0.19053300 -5.90013800 -0.00004500
O             -1 -3.75805400 -3.29704300 -1.32824400
O             -1 -2.02078900 -4.57260600 1.32815600
O             -1 -3.75802400 -3.29700300 1.32815600
O             -1 -2.02081800 -4.57264600 -1.32824400
O             -1 -1.67701200 -2.28365300 -0.00008300
C             -1 -3.02913800 -4.12510400 -1.77274000
H             -1 -3.26498400 -4.61296500 -2.77573000
C             -1 -3.02909800 -4.12505000 1.77266000
H             -1 -3.42394000 -4.49611800 2.77567000
Ti             -1 1.95280700 -3.63187100 -0.00006600
O             -1 1.94819400 -5.57265800 -0.00004400
Ti             -1 4.04976900 -0.77603300 -0.00006600
O             -1 5.90013800 -0.19053300 -0.00004500
O             -1 0.51383700 -3.35390300 -1.33369100
O             -1 0.51386700 -3.35386300 1.33350900
O             -1 3.29704300 -3.75805400 -1.32824400
O             -1 4.57260600 -2.02078900 1.32815600
O             -1 3.29700300 -3.75802400 1.32815600
O             -1 4.57264600 -2.02081800 -1.32824400
O             -1 2.28365300 -1.67701200 -0.00008300
C             -1 0.99076600 -6.46645800 -0.00005000
H             -1 1.24783300 -7.57703600 -0.00003600
C             -1 4.12510400 -3.02913800 -1.77274000
H             -1 4.61296500 -3.26498400 -2.77573000
C             -1 4.12505000 -3.02909800 1.77266000
H             -1 4.49611800 -3.42394000 2.77567000
Ti             -1 -1.95280700 3.63187100 -0.00006600
O             0 -0.30485833 7.36469334 -0.83835172
Ti             -1 -4.04976900 0.77603300 -0.00006600
O             -1 -5.90013800 0.19053300 -0.00004500
O             -1 -3.35390300 -0.51383700 -1.33369100
O             -1 -3.35386300 -0.51386700 1.33350900
O             -1 -3.29704300 3.75805400 -1.32824400
O             -1 -4.57260600 2.02078900 1.32815600
O             -1 -3.29700300 3.75802400 1.32815600
O             -1 -4.57264600 2.02081800 -1.32824400
O             -1 -2.28365300 1.67701200 -0.00008300
C             -1 -6.46645800 -0.99076600 -0.00005000
H             -1 -7.57703600 -1.24783300 -0.00003600
C             -1 -4.12510400 3.02913800 -1.77274000
H             -1 -4.61296500 3.26498400 -2.77573000
C             -1 -4.12505000 3.02909800 1.77266000
H             -1 -4.49611800 3.42394000 2.77567000
Ti             -1 3.63187100 1.95280700 -0.00006600
O             -1 5.57265800 1.94819400 -0.00004400
Ti             -1 0.77603300 4.04976900 -0.00006600
O             0 1.01705093 5.67006570 -0.58897368
O             -1 3.35390300 0.51383700 -1.33369100
O             -1 -0.51383700 3.35390300 -1.33369100
O             -1 3.35386300 0.51386700 1.33350900
O             -1 -0.51386700 3.35386300 1.33350900
O             -1 3.75805400 3.29704300 -1.32824400
O             -1 2.02078900 4.57260600 1.32815600
O             -1 3.75802400 3.29700300 1.32815600
O             -1 2.02081800 4.57264600 -1.32824400
O             -1 1.67701200 2.28365300 -0.00008300
C             -1 6.46645800 0.99076600 -0.00005000
H             -1 7.57703600 1.24783300 -0.00003600
C             0 0.92539211 6.92777570 -0.94386787
H             0 1.74913000 7.62657183 -1.30802003
C             -1 3.02913800 4.12510400 -1.77274000
H             -1 3.26498400 4.61296500 -2.77573000
C             -1 3.02909800 4.12505000 1.77266000
H             -1 3.42394000 4.49611800 2.77567000
H             -1 1.08940000 1.48337900 -0.00042100
H             -1 -1.48337900 1.08940000 -0.00042100
H             -1 1.48337900 -1.08940000 -0.00042100
H             -1 -1.08940000 -1.48337900 -0.00042100
C             0 -2.35707572 7.63782251 -0.82778338
H             0 -2.51369827 8.68529494 -0.67556355
H             0 -1.35317249 7.47167543 -1.15865111
H             0 -3.04075328 7.27890019 -1.56849910
C             0 -2.59254204 6.88595334 0.49541289
O             0 -2.41818585 5.70539654 0.32337204
O             0 -1.67710747 7.36381768 1.48461722
H             0 -0.84505554 6.67784487 2.00414306
C             0 -4.52796568 8.16786442 -0.42788732
H             0 -5.46666852 7.65725863 -0.48283000
H             0 -3.93388400 7.91491992 -1.28110830
H             0 -4.69701639 9.22429862 -0.41149751
O             0 -3.84147017 7.77643988 0.76392254
H             0 -4.32086669 7.93174429 1.75024768

sobereva · 发表于 Post on 2024-9-11 00:07:00

PM6是半经验方法，此时没有一般的基组的概念
半经验方法算牵扯过渡金属的情况靠谱程度很低，非要用半经验级别的方法试算建议看下文
将Gaussian与Grimme的xtb程序联用搜索过渡态、产生IRC、做振动分析
http://sobereva.com/421（http://bbs.keinsci.com/thread-10106-1-1.html）

必要时结合柔性扫描帮助判断过渡态初猜

fuhua · 发表于 Post on 2024-9-11 15:08:25

sobereva 发表于 2024-9-11 00:07
PM6是半经验方法，此时没有一般的基组的概念
半经验方法算牵扯过渡金属的情况靠谱程度很低，非要用半经验 ...

感谢sob老师~我去仔细研读一下~

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[综合交流] 求助：gaussian模拟金属催化甲酸与甲醇酯化反应过程，为什么不反应呢？