当前位置: 首页 > 晶体 >配位水上的氢是关于镜面对称的,看了审稿意见仍然加不好,求助各位虫友,成分感激

配位水上的氢是关于镜面对称的,看了审稿意见仍然加不好,求助各位虫友,成分感激

作者 shiandtian
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以下是审稿意见:
Hydrogens of the coordinated water molecules O(1W) and O(2W). Refining hydrogens in close proximity to a heavy atom, especially on room-temperature data, is seldom successful, especially as both O lie on a mirror plane, so in the suggested models each H is disordered between two positions. Thus, some O-H bonds are almost pointing towards the lanthanide atom, with unrealistically short H...Ln contacts of 2.10-2.35 Ang (in one case in 4, as short as 1.76 Ang). Then, these hydrogens do not make a sensible network of hydrogen bonds, which is improbable when there are plenty of acceptors (O) nearby. My suggestions are shown in the attached file 7.res. Here, O(2W)  has its hydrogens related by the mirror plane, hence only one independent H with occupancy of 1. It forms a hydrogen bond with O(3W). Thus there is no hydrogen directed towards the metal. At O(1W), one H atom lies on the mirror plane (like the O itself) and forms H-bond with O(2W)(2-x, y, -z), related by twofold axis. The other H is disordered between two positions related by the mirror plane, and interacts with O(4A)(2-x,1-y,1-z). Note that the latter atom has occupancy of 0.5, which agrees well with the half-occupancy of the H. In this file, O(5W), O(6W) and O(7W) have increased occupancies, better fitting the electron density, so now there is 1.75 H2O per asymmetric unit, or 3.5 per formula unit, and the formula should be
        
_chemical_formula_moiety  ‘C23 H19 Er O10, 3.5(H2 O) '
_chemical_formula_sum            'C23 H26 Er O13.5'
_chemical_formula_weight          686.35
_exptl_absorpt_coefficient_mu     3.798
_exptl_crystal_density_diffrn     1.724
Structures 4 and 5 can be treated similarly.

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  • leaves922

    把水分子放进part -1试试,占据数10.5

  • shiandtian

    引用回帖:
    2楼: Originally posted by leaves922 at 2017-08-18 17:36:02
    把水分子放进part -1试试,占据数10.5

    试过了,不过还是出现了3个H,有一个还键连不上~

  • shiandtian

    引用回帖:
    2楼: Originally posted by leaves922 at 2017-08-18 17:36:02
    把水分子放进part -1试试,占据数10.5

    不好意思,记错了,‘把水分子放进part -1试试,占据数10.5’后,有两个H原子,但是它们和O1W不键连~DFIX 后,会出现3个H,有一个是对称位置的

  • lich666

    特殊位置上加一个氢,占有率是1就行了。注意OH键长为0.85,HH键长为1.4就行了。不用part -1那么麻烦。

  • shiandtian

    引用回帖:
    5楼: Originally posted by leaves922 at 2017-08-19 09:59:01
    非特殊位置的更改一部分H的指向,特殊位置的水分子无序要做part-1,如果特殊位置都在part-1有键连,要单独拿出来做part-2,而且特殊位置的占据数都是0.5
    ...

    我还是不太懂,请问如何更改H的指向,非特殊位置与特殊位置指是什么

  • shiandtian

    引用回帖:
    6楼: Originally posted by lich666 at 2017-08-19 12:26:11
    特殊位置上加一个氢,占有率是1就行了。注意OH键长为0.85,HH键长为1.4就行了。不用part -1那么麻烦。

    不太懂,特殊位置是什么?

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