各位牛牛好！

我最近看到一篇文献里有这样的内容：
Coordinated compounds can be described by the structural parameter τ (τ describes the relative amount of trigonality; τ = 0 for square pyramidal and τ = 1 for trigonal bipyramidal)
我最近要写的文章的那个结构是五配位，我想查一下那个τ值，不知道在cif或lis文件里的什么地方，或在SHELXL里用什么命令得到？
那个符号不是T，只因打不出，其实发汉语拼音因为“tao”值 ！
谢谢！

各位牛牛好！

我最近看到一篇文献里有这样的内容：
Coordinated compounds can be described by the structural parameter τ (τ describes the relative amount of trigonality; τ = 0 for square pyramidal and τ = 1 for trigonal bipyramidal)
我最近要写的文章的那个结构是五配位，我想查一下那个τ值，不知道在cif或lis文件里的什么地方，或在SHELXL里用什么命令得到？
那个符号不是T，只因打不出，其实发汉语拼音因为“tao”值 ！
谢谢！

Hi! Smith. τ (=Tau) value of a certain five coordinate compound usually was calculated manually. You may read the following reference for detail.
A. A.W. Addison, T.N. Rao, J. Reedjik, G.C.J. Verschoor,
J. Chem. Soc., Dalton Trans. (1984) 1349

The tau value ranges from 0 to 1, zero being perfectly
square pyramidal and one being perfectly trigonal bipyramidal. The tau
equation is show in the attached figure. The substituents around the metal are labeled a–e, with ‘‘a’’ being the substituent which does not help define either of the two largest angles around the metal. If ‘‘a’’ is defined as the z axis, then alpha (‘‘c’’ to ‘‘e’’) and beta (‘‘b’’ to ‘‘d’’) are the angles that are opposite from each other in the xy plane.

According to the definition of tau value above, the steps to get the tau value of a compound are as follows:
1) Getting X-ray structural data of the five coordinate compound first.
2) finding all of the bond angles (total 10 angles) involving the central metal atom such as:
a-M-e
a-M-b
a-M-c
a-M-d
b-M-c
b-M-d
b-M-e
c-M-d
c-M-e
d-M-e
3) Picking out the two largest angles.
4) (The largest-the second largest)/60
5) If the Tau value is close to 0, such as 0.15, you may describe your compound possessing a distorted sp geometry; if it is close to 1, such as 0.90, you may say it with distorted trigonal bipyramidal geometry.

[ 本帖最后由 niuniu123 于 2006-9-17 06:58 编辑 ]

非常谢谢！
那个参考文献我昨天也看啦，但由于理解水平有限，没有看明白！
但看了这个具体步骤，对新手我而言方便多啦，我现在就开始计算！

give you a big golden "yuanbao" for bonus!!!

在牛牛老师的指点下，学生我开始做作业啦！
1、
O(1)-Zn(1)-O(2)=58.62 (13),
O(1)-Zn(1) -O(3)=132.82(13),
O(1)-Zn(1)-O(4)=101.17(14),
O(1)-Zn(1)-N(1)=116.05(14),
O(2)-Zn(1)-O(3) =92.47(12),
O(2)-Zn(1)-O(4)=159.60(13),
O(2)-Zn(1)-N(1)=91.61(13),
O(3)-Zn (1)-O(4)=104.93 (15),
O(3)-Zn(1)-N(1)=99.68(14),
O(4)-Zn(1)-N(1)=95.76(14),

2、τ =(159.60-132.82)/60=0.4633

3、那这一个值又应怎么表述呢，是不是属严重扭曲的square pyramidal 还是trigonal bipyramidal呢，我想在写文章时表述科学一点，能打动编辑的心！

4、图见下，不过不知能不能上传！

You may say that "The tau value (0.46) of compound X reveals that the geometry around the zinc atom is nearly in between the square pyramidal and trigonal bipyramidal geometry."

牛牛太理解兄弟我啦！

谢谢！！！

引用:

原帖由 smithchencsc 于 2006-9-17 13:21 发表
牛牛太理解兄弟我啦！

谢谢！！！

Could u upload the cif to chem8? I am curious about the factor leading to such a distortion. steric effect or electronic?

Thx.

引用:

原帖由 Metalcarbene 于 2006-9-18 00:46 发表

Could u upload the cif to chem8? I am curious about the factor leading to such a distortion. steric effect or electronic?

Thx.

我目前还没有上传文件的权限！

如果Metalcarbenzene感兴趣，我们可以在下面传给你研究！

现人在外，自己电脑不在身边！
刚发现，上传功能已开通！
回来后再上传！
烦请Metalcarbene兄再等两天再研究吧！