共查询到20条相似文献，搜索用时 93 毫秒
1.
以邻菲罗啉(Phen)和邻氨基苯磺酸为配体,与硝酸镍利用水热合成法合成标题配合物{[Ni(Phen)3]·L·(OH)}(L=邻氨基苯磺酸阴离子)。通过红外光谱和元素分析对标题配合物进行结构表征,X-射线单晶衍射结果表明,标题配合物的分子式为:C42H31O4N7SNi,Mr=788,属单斜晶系,空间群为C2/c,晶胞参数:a=23.119?,b=15.792?,c=25.040?,β=111.2°,V=8523.3?3,Z=8,R1=0.0808,ωR2=0.2447。标题配合物由一个配阳离子[Ni(Phen)3]2+,一个邻氨基苯磺酸阴离子和一个氢氧根离子组成。在配阳离子中,中心Ni(II)与三个phen分子的六个氮原子配位,形成六配位的八面体构型。配阳离子通过静电引力与阴离子结合。化合物分子间通过氢键和Phen环π-π堆积作用形成三维结构。 相似文献
2.
《云南教育》2007,(3)
有关圆选择题1.(临沂)如图,在Rt△ABC中,AC=5,BC=12,⊙O分别与边AB、AC相切,切点分别为E、C,则⊙O的半径是()。A.10/3B.16/3C.20/3D.23/32.(鄂州)如图,A是半径为1的⊙O外的一点,OA=2,AB是⊙O的切线,点B是切点,弦BC//OA,连结AC。则图中阴影部分面积等于()。A.π/6B.π/3c.π/2D.(π/3)-3～(1/2)π/3c.π/2D.(π/3)-3～(1/2)A.π/6B.π/3c.π/2D.(π/3)-3～(1/2)B.π/3c.π/2D.(π/3)-3～(1/2)连结AC。则图中阴影部分面积等于()。A.π/6B.π/3c.π/2D.(π/3)-3～(1/2)2006年全国中考数学新题集锦~~… 相似文献
3.
4.
配合物Zn(phen)2[(C6H5)2C(OH)COO]2的水热合成及晶体结构 总被引：1，自引：0，他引：1
黄旭军 《衡阳师范学院学报》2008,29(3):73-75
在甲醇和水的混合溶剂中用二苯乙醇酸、邻菲罗啉(phen)、高氯酸锌合成了一种新型配位聚合物Zn(phen)2[(C6H5)2C(OH)COO]2.该配合物晶体属三斜晶系,空间群C2/c,晶胞参数:a=2.5912(4),b=1.13381(17),c=1.7457(3)nm;β=1 123.697(2)0,V=4.2671(11)nm3,Dc=1.370g/cm3,Z=4,F(000)=1824.最终GooF=1.005,最终偏离因子R1=0.0367,wR2=0.0834.晶体中锌原子与2个邻菲罗啉的4个N原子及2个二苯乙酸根4个羧基氧原子中的两个氧原子配位,形成六配位的变形八面体结构. 相似文献
5.
在溶剂热条件下,MnCl2·4H2O,四氮唑-1-乙酸(1-tza)和邻菲罗啉(phen)在乙腈溶剂中反应得到一个新型单核配合物[Mn(1-tza)2(phen)2]·H2O(1),该配合物通过氢键作用在ab面形成一维链状超分子结构,链与链之间又通过π-π堆积形成二维层状超分子结构.配合物1的晶体数据为:C30H24MnN12O5,M=687.55,空间群为P2(1),a=9.163 10(10),b=15.475 5(2),c=21.446 7(2),α=γ=90°,β=101.79°,V=2 977.04(6)3,z=4,Dc=1.534 Mg/m3,R1=0.046 8,wR2=0.136 2. 相似文献
6.
通过还原剂保护法合成了二价稀土铕的邻菲咯啉配合物并进行了元素分析、红外等表征,测定了配合物的晶体结构:配合物组成为[Eu(Phen)_2·cl_2],单斜晶系,P2(1)/c空间群,晶胞参数α=9.6039(9)■,b=15.1374(14)■,c=14.6339(14)■,β=99.6170 (10)°,Z=4,Mr=583.27,D_c=1.848 Mg.m~(-3),R_1=0.0629,wR_2=0.2014。铕为6配位,两个邻菲咯啉作为螯合配体参与配位,另两个配位点被Cl原子占有。 相似文献
7.
正一、问题提出题已知△ABC中,3(1/2)tanA·tanB-tanA-tanB=3(1/2).(1)求∠C的大小;(2)设角A,B,C的对边依次为a,b,c,若c=2且△ABC是锐角三角形,求a2+b2的取值范围.解(1)C=π/3(略).(2)学生解1:由余弦定理得a2+b2-ab=4. 相似文献
8.
制备了一个新的钴的[Co(C4H3N2CoO2)2(H2O)4](C4H4N2CoO2=4,6-二羟基嘧啶),通过X-射线衍射、热重分析和荧光光谱对配合物的结构和性质进行了测试和表征.晶体结构分析表明,该晶体属于单斜晶系,空间群C2/c,晶胞参数:a=13.528(3),b=7.2240(13),c=13.001(2);α=90°,β=109.448(2)°,γ=90°;V=1198.0(4)3,μ=1.485mm-1,Dc=1.958 Mg/m3,F(000)=724,R=0.0302,wR=0.0894(I>2σ(I)).在配合物的结构单元中,Co原子与两个4,6-二羟基嘧啶和四个水分子配位,形成略有畸变的拉伸八面体配合物.配合物的结构单元[Co(C4H3N2CoO2)2(H2O)4]之间进一步通过分子间氢键和π-π堆积作用相互交叉连接在一起形成三维超分子化合物. 相似文献
9.
题目:已知a、b、c是锐角三角形ABC的三个内角A、B、C所对的三边,tg1/2A=tg~3 1/2 C,sinBcosC=sin(C-B),并且a、b、c、成等比数列,试证明△ABC是正三角形。有一本书给出的解答提示如下:“先由已知条件和A+B+C=π导出B=1/3π,再由余弦定理证明 a=c,则△ABC是正三角形”。其实,这道题是不妥的。为了便于分析,笔者根据以上提示猜测其证明过程为: 由已知 sinB·cosC=sin(C-B) 得 sinB·cosC=sinCcosB-cosCsinB化简得 2sniB·cosC=sinC·cosB ① 相似文献
10.
《新高考》2007,(10)
第Ⅰ试1.D2.A3.C4.A5.B6.B7.B8.C9.A10.D11.End If12.y=-x 413.2514.215.4216.S2=mS1,S椭圆=πab17.(1)因为tanB=csionsBB,cosB=a2 2ca2c-b2,而tanB=a2 3ca2c-b2,可得sinB=23.(2分)因为B为锐角,所以B=60°.(4分)(2)sin(B 10°)[1-3tan(B-10°)]=sin70°[1-3tan50°](6分)=sin70°1-3·csions5500°°(10分)=sin70°·cos50c°o-s503°sin50°=2sin70°·sin(c3o0s°5-0°50°)(12分)责编/朱凌燕顾俊邮箱/gujun071001@163.c44高三语数外=-2sins2i0n°4c0o°s20°=-1.(14分)18.(1)根据俯视图可知,ABCD是边长为a的正方形,且A1H⊥… 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
14.
15.
16.
《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
17.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
18.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
19.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献