配位化学课件Coordination--Compound1

,Department of Material and Engineering, Soochow University,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,Coordination,chemistry,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,Department of Material and Engineering, Soochow University,Coordination Chemistry,Coordination Compound (Metal Complexes),Part One,Introduction and Historical Development,Part Two,The Theory of Coordination Compounds,Part Three,Stereochemistry of Complexes,Part Five,Complex Ion Stability,Part Six,Kinetics and Mechanisms of Reactions of Coordination Compounds,Part four,Preparations and Reactions of Coordination Compounds,1-1.,Indroduction,Lets review/go over some of their properties or characteristics:,At a very early stage (such as at your first year in the class of inorganic chemistry), the students were introduced to a series of compounds referred to as/called:,coordination compounds,(metal complexes),(complexes in brief).,1-3. Nomenclature,1-1.,Indroduction,1-2. Historical Development,Part OneIntroduction and Historical Development,Socialism with Chinese characteristics. That car is myproperty. Property management, intellectual property, mechanical property,(1),These compounds generally contain a,central ion,( usually a metal ion),surrounded by a cluster of ions or molecules.,(2),These complexes tend to,retain/maintain their identity,/integrity even in solution, although partial dissociation may occur.,Identity card; reveal or conceal/cover up your identity; territorialintegrity; A man of moralintegritydoes not fear any slanderous attack,(3),These complexes may be,cations,or anions or,nonionics, depending on the sum of the charges of the central atom and the surrounding ions or molecules.,一,.,Coordination compounds play an essential role in the chemical industry and in our lives.,(1),In 1963 Nobel prize in chemistry was awarded jointly/together to,Dr. K.,Ziegler,of the Max Plank Institute, in Germany, and to Prof.,G. Natta,of the University of Milan. Italy.,academy award, financial reward,They developed,a new kind of,catalyst, using it they,could prepare the polymerization of ethylene under low pressure, which makes thousands of,polyethylene articles,commonplace/ ordinary.,articles consumption,(these articles are very common in market),This,Ziegler-Natta catalyst,for this polymerization is just,a complex of the metals aluminum and titanium.,(2),The importance of metal complexes becomes clear when one realize that:,(A),Chlorophyll,kl:rfil, which is vital to photo-synthesis in plants( allows plants to absorb energy from light), is a magnesium complex,(B),Hemoglobin,hi:m,glbin,which carries oxygen to animal cells, is an iron complex.,Hemoglobin in the,blood,carries oxygen from the respiratory organs (,lungs,or,gills,) to the rest of the body (i.e. the tissues) where it releases the oxygen to burn nutrients to provide energy to power the functions of the organism, and collects the resultant,carbon dioxide,to bring it back to the respiratory organs to be dispensed/removed from the organism.,dispensable-indispensable (necessary); resultant-reactant,(C),Vitamin B,12, is a water-soluble,vitamin,with a key role in the normal functioning of the,brain,and,nervous system, and for the formation of,blood,. It is one of the eight,B vitamins,.,维生素,B,12,It is normally involved in the,metabolism,of every,cell,of the human body, especially affecting,DNA,synthesis and regulation/control, but also,fatty acid,synthesis and energy production.,It is the largest and most structurally complicated vitamin and can be produced industrially only through bacterial fermentation-synthesis.,Pernicious anemia,恶性贫血,in human is due to the failure of absorption of vitamin B,12,-Vitamin B,12,is used to treat,vitamin B,12,deficiency,cyanide poisoning,(hydrogen, potassium, sodium cyanide).,pernicious/hurtful/deadly/harmful/fatal, smoking is to health.,(D),Blood tonic,of,红桃,K (red spade K), which has been available in market, is also an iron complex.,Blood Tonic assist the body to promote healthy blood, physical and mental powers, skin and improve healthy production of blood in various bone marrow-related health problems, especially,aplastic,anemia,再生障碍性贫血,. It also can be used as a beauty tonic because when there is sufficient blood and nutrition, the skin, the complexion/look/ appearance and hair will improve and project/show or display good health as well as retard/delay aging and prolong the youthfulness of the body.,Healthy blood is not only necessary for nourishing your body, but also important in the healthy development of your mind. When blood quality is unhealthy,typical symptoms are pale complexion, dry skin, dizziness, ringing in the ears, forgetfulness, insomnia/sleeplessness and menstrual disorder in women, premature gray hair and many other disharmonies.,(E),Sodium and calcium salts of EDTA, which is a highly effective antidote or,toxicide,in preventing people from radiating of radioactive elements, is an complex.,(F),Several complexes of platinum,can be used as strong anti-cancer medicines, which are being experimented( or used ) in clinic.,(3),It is almost certain that you have already encountered/run across coordination compounds in laboratory or elsewhere.,They are used extensively in,qualitative analysis,as a means of,separating,certain metal ions and as a means of positively,identifying,certain unknown ions (particularly metal ions).,intensive/extensive reading, extended family,For example:,You have perhaps performed ( or carried out) the experiment :,“how to identify silver ion in solution?”,You can state/account for/explain the problem in the following way:,(i),You can add,chloride,kl:raid,ion to the solution, which gives an white precipitate of silver chloride immediately;,PbCl,2,or,CuCl,is also an white precipitate; a slight mistake could precipitate/result in a disaster; make a precipitate/cavalier/careless decision,(ii),Then, adding an excess of aqueous ammonia to the solution, the precipitate can dissolve and become a clear solution.,(iii),But if you continue to add an excess of nitric,naitrik,acid, the precipitate will appear again.,These behaviors are due to the existence of the two,equilibria,(1) (2):,Explain:,(i),Because silver chloride is,not soluble,/ insoluble in water, it does, however, dissolve in excess NH,3,and forms the stable complex ion -,Ag(NH,3,),2,+,;,(ii),The addition of excess of HNO,3,to the clear solution causes the equilibrium,(2),to shift to the left, and so the white precipitate reappears.,(iii),It is due to the reduction or lowing of concentration of NH,3,which has reacted with H,+,to form NH,4,+,.,(4),The formation of metal complexes is often accompanied by very striking/significant changes in color.,You have learned lots of these examples in inorganic chemistry and done a large number of experiments in laboratory.,Here, giving an interesting example:,You may be familiar with the use of the solutions of CoCl,2,as,invisible ink:,Writing down with this almost colorless solution on paper,you can see the following phenomena:,(A),It is virtually/actually invisible.,(B),When being heated, the water is driven off; the blue complex CoCoCl,4, is formed.,(C),The color is notably intense so that the writing can easily be read.,intense pain/emotion/cold/competition; intense/dark green,(D),But on standing, water is slowly taken up by the surrounding atmosphere and the original colorless complex Co(H,2,O),6,Cl,2,is regenerated, which makes the writing invisible again.,(i),Those phenomena are due to the existing of the following,equilibium,(3):,Explain:,(iii),But the writing becomes a very legible/clear blue color when the writing of the paper is heated, and then this distinct color slowly disappears( or becomes invisible again).,(ii),That is to say, this diluted solution is almost colorless ( it is actually slight pink due to the complex Co(H,2,O),6,2+,), when you write something on paper with this solution, it is practically invisible).,The above examples can positively illustrate our point that,coordination compounds are common, important and frequently encountered.,(5),On the other hand, coordination compounds are extensively used in dying and finishing industry. Maybe you will encounter these problems in the future.,二,.,The direction of research and applied prospects of coordination compounds can be summarized as follows:,1.,the syntheses of neo-type or new-style complexes,(a) The inorganic,(b) metal,(c) polymer materials,have been listed as three current major materials.,(A),They are extensively applied in many ways of,high-temperature; resistant,( to fire, erosion and oxidation, etc.) materials.,(B),Furthermore, the syntheses of complexes are extremely emphasized on functional materials such as ones of,light;,heat;,electricity;,magnetism .,(A),The complexes can be used as,reagents/reactants,intermediates,catalysts,in organic synthetic industry.,2.,The research of complexes into the properties of the utility and simulated performance,(B),The development and utility of these,small molecules,such as N,2, CO, HCHO, CH,4,is the important basis of current chemical industry.,In these reactions large numbers of,carbonyl,k:bnil,complexes,and,cluster compounds,have been used to,activate these small molecules to react with oxygen.,These oxidation reactions can release large amounts of energy which can be used in many ways.,(C),Many organic,ligands,have extensively been used as,developers (,显色剂,),，,precipitants (,沉淀剂,),extractants,（萃取剂）,titrants,（滴定剂）,masking agents,（掩蔽剂）,anti-masking agent,in elementary analysis.,三,. The term “complex compounds” is no longer the meaning of itself,(A),Until the beginning of the last century the nature of these materials were not fully understood, and the compounds were referred to as “complex compounds”.,(B),This term is still used nowadays but fortunately no longer for the same reason.,(C),After extensive research on such systems, our knowledge has so increased that,the systems are no longer considered complicated.,(D),In fact,the knowledge of the properties of complexes is showed more significantly important,if you want to understand the chemistry of metals.,1-2. Historical Development,Students should keep in mind that scientific development usually comes from a somewhat,regular fashion:,(i),Collect as many facts ( or as much information) as possible by means of many carefully designed experiments.,1-1.,Indroduction,1-2. Historical Development,1-3. Nomenclature,(ii),Attempt to explain and correlate all the facts with a suitable theory ( or a theory available at that time).,Students should also remember that unlike experiments, theories can be modified, even at times (sometimes) completely discarded as more and more information becomes available.,1-2-1. Discovery and properties,(,一,). It is hard or difficult to state exactly which complex is the first one discovered ( and when).,Perhaps the earliest one on record is,Prussion,blue:,KCNFe(CN),2,Fe(CN),3,(current formula is KFe(CN),6,Fe,x,),which obtained by an art color maker,Diesbach, in Berlin at the beginning of the eighteenth century (1740).,It was said or reported that in order to find out a kind of blue dye,Diesbach,mixed:,several animals skins, blood and Na,2,CO,3,heated them on an iron pot, then got an kind of blue compound, which is called,Prussion,blue.,Note:,CN,is produced by the hydrolysis of amino acids (animals skins),Usually, the first complex is considered as,hexaamminecobalt,() chloride,CoCl,3,6NH,3, discovered by,Tassert,(1798, who is an analytic chemist in France).,This discovery marked the real beginning of,coodination,compound because its,unique properties,stimulated considerable interest and research on the similar systems and compounds.,stimulate(stimulus,sting, distinguish) ,simulate(similar,),But this complex could not explained by the chemical theories available at that time.,So it is necessary to understand,how CoCl,3,and NH,3, two stable compounds of presumably saturated valence, could combine together to make another yet very stable compound?,It is a puzzle and a stimulus for chemists to further study and research.,But the answer was not to be found until,approximately 100 years later.,During that period of time,many such compounds were prepared; and their properties studied; several theories were proposed and then discarded,-,Because they were inadequate to explain subsequent/ next/following experimental data.,such as,chain theory,by,Blomstrand,-Jorgensen,reference the middle part on page 2 in your book,(,二,). Generally, the preparation of metal complexes involves the reaction between a salt and some other ions or molecules such as H,2,O, NH,3,Cl,(X,), NO,2, NCS, CN, ,For example:,PtCl,2,2NH,3,/ Pt(NH,3,),4,PtCl,4,-,Rrdmann,salt;,Co(NO,2,),3,KNO,2,2NH,3,/ KCo(NH,3,),2,(NO,2,),4,-,Magnus salt (green).,At first,each complex was named after the chemist who originally prepared.,Secondly,the complexes were named on the basis of color because many of the compounds are colored.,For instance:,CoCl,3, 6NH,3,-,luteo,/yellow,cobaltic,chloride;,CoCl,3, 5NH,3,-,purpureo,/purple,cobaltic,chloride;,CoCl,3, 5NH,3,H,2,O,-,roseo,/red,cobaltic,chloride.,Clearly, these systems above mentioned were not practical and had to be abandoned or changed.,The corresponding nomenclature of complexes will be discussed later.,Like these complexes CoCl,3,xNH,3, they differ not only in their colors, but also in the reactivity of their chlorides.,You can see this from the following experimental results of such studies:,Comlexes,number of,Cl,ions,precipitated by Ag,+,CoCl,3,6NH,3,3,CoCl,3,5NH,3,2,CoCl,3,4NH,3,1,There are two kinds of chlorides:,(i),One type is perhaps similar to that in sodium chloride, which is readily precipitated as,AgCl,;,(ii),The other type is held more firmly and not precipitated.,(,三,). The electrical conductivity of a complex solution can also provide useful information,It can determine,the number of ions,presented in solution of different complexes.,Under the same condition (such as the same concentration), comparing the electrical conductivity of different complexes, we can estimate the number of ions,in each complex solution.,Comlexes,PtCl,4,6NH,3,PtCl,4,5NH,3,PtCl,4,4NH,3,molar electrical,Conductivity,(,欧姆,obm,-1,),523,404,229,estimated results (number of ions in solution),5,Pt(NH,3,),4,4+, 4Cl,4,Pt(NH,3,),4,3+, 3Cl,3,Pt(NH,3,),4,2+, 2Cl,For example:,(,四,). Another important property early observed was that certain complexes exist in several different forms but having the same chemical composition (which are called isomers).,For instance:,CrCl,3,6H,2,O,:,green,-,CrCl,2,(H,2,O),4,ClH,2,O,violet,-,Cr(H,2,O),6,Cl,3,blue green,-,CrCl(H,2,O),5,Cl,2,H,2,O,PtCl,2,2NH,3,Cream(light,yellow),-,Pt(NH,3,),4,PtCl,4,(,forms,),They differ in solubility, chemical reactivity, etc.,In,general:,(i),It was necessary to account for all of these experiment facts above with a suitable theory.,(ii),In history, several hypotheses and theories were proposed but proved to be wrong, and only one theory,1-2-2,Werners coordination theory,Our present understanding to the nature of metal complexes is due to the ingenious insight of the person,Alfred Werner,professor of chemistry in Zurich, Swiss;,the winner of a Noble prize in 1913.,In 1893, at the age of only 26, he proposed what is now commonly referred to as “,Werners coordination theory,”.,The theory has been a guiding principle in inorganic chemistry.,It includes three main postulates or hypotheses:,1.,Most elements exhibit two types of valence:,(1) primary valence,(corresponding to the oxidation state),(2) secondary valence,(corresponding to the coordination number).,2.,Every element tends to satisfy both its primary and secondary valence.,3.,The secondary valence is directed towards fixed positions in space.,(this is the basis of the stereochemistry of complexes),Lets explain them with examples:,(1) CoCl,3,6NH,3,primary valence - 3, Co(),secondary valence - 6(NH,3,),Here Co() is already surrounded by six ammonias, so the chloride ions (,Cl,) are farther from the metal ion and arent firmly bound.,Thus a solution of such complexes has four ions, and three,Cl,are readily precipitated by Ag+ as silver chloride.,(2) CoCl,3,5NH,3,primary valence - 2, Co(),secondary valence - 5 (NH,3,),According to postulate 2, there are only five NH,3,. So one chloride ion must serve duel functions for satisfying both.,When fronted with,(3) CoCl,3,3NH,3,( formulated as,Co(NH,3,),3,Cl,3,),the Werners theory predicted the compound would not yield,Cl,- ion solution.,The experimental results confirmed the conclusion.,This proved that the Werners theory was right.,Postulate 3,of Werners theory deals specifically with the stereochemistry of complexes.,It correctly explains many of the structural features of coordination compounds.,One particularly important contribution was,the determination of the structure of six-coordinated complexes,.,Before the discovery of x rays, the spatial configuration of molecules was determined by,comparing the number of known isomers with the number theoretically possible.,By this way (and other evidence such as optical activity), it can prove that certain structures were wrong and obtain evidence in support of a particular configuration.,Werner successfully used this