Complexes of N-Donors

The preparation of the isomeric forms of Pt(NH3)2Cl2 is discussed in terms of the trans-effect in section 3.8.9 [67]. 

These ci s-complexes of palladium are unstable and rapidly isomerize but can be made via the ci s-diaqua complex [68] 

Although the bisammine complexes of platinum(II) are the most important because of the medical applications of the m-isomer (section 3.10), the synthesis of the others [69] is also important  

High yield synthesis of Pt(NH3)3Cl+ is difficult [67] the traditional method of Chugaev (/. Chem. Soc., 1915, 1247), which relies on the hydrolysis of NCO- to generate ammonia, is the most widely used 

Another route ultimately relies on replacement of a labile water molecule trans-Vt(NH3)2C12 trans-Pt(NH3)2ClI AgN°3 

Hiffh vield svnthesis of PtrNH,t,Cl is difficult f671 the traditional method 

Since thiourea has a high traiu-influence, the ammonia trans to it is replaced, repetition of the sequence causing the formation of yellow needles of Pt(tu)4Cl2. 

The best examples of complexes with bidentate N-donors are those with 2,2 -bipyridyl (bipy) and 1,10-phenanthroline (phen). Complexes LnL2(N03)3 (L = bipy, phen) have been studied in detail and have 10-coordinate structures with all nitrates bidentate 

The structure of La(phen)2(N03)3 (reproduced by permission of the American Chemical Society from M. Frechette, I.R. Butler, R. Hynes, and C. Detellier, Inorg. Chem., 1992, 31, 1650). 

A number of chloride complexes include Pr(terpy)Cl3.8H2O X-ray diffraction established the presence of a [Pr(terpy)C1(H20)5] + ion. Lanthanide nitrates react with 1 mole of terpy in MeCN to give [La(terpy)(N03)3(H20) ] (Ln = La, = 2 Ln = Ce-Ho, n = 1 Ln = Er-Lu, n = 0) with coordination numbers decreasing from 11 (La) to 9 (Er-Lu) if these are crystallized from water [Ln(terpy)(N03)2(H20)4] NO3 (Ln = La-Gd) and [Ln(terpy)(N03)2(H20)3]N03.2H20 (Ln = Tb-Lu) are formed these have both biden-tate and ionic nitrate and nine- and eight-coordinate lanthanides, respectively. Thiocyanate complexes Ln(terpy)2(NCS)3(Ln = Pr, Nd) are also nine coordinate. 

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Platinum(IV) forms complexes with a range of ligands [1, 2, 10, 11]. 3.10.1 Complexes of N-donors... 

Fig. 11 zinc complexes of N-donor imino, NHC, and scorpionate ligands... 

Relatively few complexes of N-donor ligands are known. One of the best characterized is with the tridentate ligand terpyridyl, which reacts with scandium nitrate to form Sc(terpy )(N03 )s here scandium is connected to 9 atoms, but one Sc-O bond is considerably longer than the others, so a coordination number of 8.5 has been assigned. A range of porphyrin and phthalocyanine complexes exist syntheses often involve the high-temperature routes typical of the transition metals but recently a high-yield low-temperature route has been utilized to make octaethylporphyrin (OEP) complexes ... 

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