24小时热门版块排行榜    

查看: 1747  |  回复: 4
当前只显示满足指定条件的回帖,点击这里查看本话题的所有回帖

魏超

金虫 (正式写手)

平平淡淡

[求助] 有3个B错误,请大家帮忙解决一下 已有1人参与

Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    O2     --  C1      ..       13.0 su   
PLAT417_ALERT_2_B Short Inter D-H..H-D       H2A    ..  H7A     ..       1.87 Ang.
PLAT420_ALERT_2_B D-H Without Acceptor       O7     -   H8A    ...          ?      
--------------------------------------------------------------------------------
分别为
PLAT230 Type_2 Hirshfeld Rigid-Bond Test (Acta Cryst (1976),A32,239-244
--------------------------------------------------------------------------------

The components of the anisotropic displacement parameters along chemical
bonds are assumed to be equal in magnitude. Large differences might
indicate contamination of these parameters with other (unresolved) effects
such as (substitutional) disorder, model or data errors and/or
over-refinement. Atomic sites assigned the wrong scattering type (e.g. Ag
versus Br) should generate 'problem signals' with this test. Data sets
corrected for absorption effects with DELREF techniques (e.g. DIFABS, SHELXA,
XABS2) often show large DELU values for bonds involving the heaviest atom.
Note: The original 'Hirshfeld-test' was defined in absolute terms (see
F.L.Hirshfeld, Acta Cryst. (1976). A32, 239-244). The current test is with
reference to the associated standard uncertainty.

PLAT417 Type_2 Test for short non-bonding inter D-H..H-D contacts
--------------------------------------------------------------------------------

Short non-bonding inter D-H..H-D contacts may be related to disordered or
misplaced H-atoms.
Experience has shown that any intermolecular H...H separation of less than
1.8 Angstroms between unit-occupancy H atoms is a clear indicator that one
or both of these H atoms may be wrongly placed.

PLAT420 Type_2 Test for D-H without acceptor
--------------------------------------------------------------------------------

Potential hydrogen bond donors are checked for the presence of suitable
acceptors using commonly used (Jeffrey) H-bond criteria. As a general rule
there should be an acceptor for each donor. Exceptions are very rare for O-H
and more common for -NH and -NH2. A common error is an -OH on a calculated
position pointing in the wrong direction.

[ Last edited by 魏超 on 2013-2-24 at 10:01 ]
回复此楼

» 猜你喜欢

» 本主题相关价值贴推荐,对您同样有帮助:

已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

魏超

金虫 (正式写手)

平平淡淡

引用回帖:
2楼: Originally posted by 08113113 at 2013-02-24 10:09:42
第一个是刚性太强了,可以试试DELU C1 O2指令。后面的O7上氢加的有问题,而且氢的命名也不合理,O7接上H8A呢。

感谢您的帮助,不过我还要麻烦您,DELU C1 O2这个指令在什么地方加,怎么编写,我没有用过,请您给详细写一下。后面的问题,我会改的。请您帮助,谢谢
3楼2013-02-24 11:49:49
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
相关版块跳转 我要订阅楼主 魏超 的主题更新
信息提示
请填处理意见