Problem 17
State the types of isomerism that may be exhibited by the following complexes, and draw structures of the isomers: (a) \(\left[\mathrm{Co}(\mathrm{en})_{2}(\mathrm{ox})\right]^{+},(\mathrm{b})\left[\mathrm{Cr}(\mathrm{ox})_{2}\left(\mathrm{OH}_{2}\right)_{2}\right]^{-}\) (c) \(\left[\mathrm{PtCl}_{2}\left(\mathrm{PPh}_{3}\right)_{2}\right],(\mathrm{d})\left[\mathrm{PtCl}_{2}\left(\mathrm{Ph}_{2} \mathrm{PCH}_{2} \mathrm{CH}_{2} \mathrm{PPh}_{2}\right)\right]\) and (c) \(\left[\mathrm{Co}(\mathrm{cn})\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\right]^{2+}\)
Problem 18
Using spectroscopic methods, how would you distinguish between the pairs of isomers (a) cis- and trans\(\left[\mathrm{PdCl}_{2}\left(\mathrm{PPh}_{3}\right)_{2}\right]\) (b) \(c\) is- and \(\operatorname{trans}=\left[\mathrm{PtCl}_{2}\left(\mathrm{PPh}_{3}\right)_{2}\right]\) and (c) \(f a c-\) and \(\operatorname{mer}-\left[\mathrm{RhCl}_{3}\left(\mathrm{PMe}_{3}\right)_{3}\right]\)
Problem 19
Comment on the possibility of isomer formation for each of the following complexes (the ligand tpy is \(2,2^{\prime}: 6^{\prime}, 2^{\prime \prime}=\) terpyridine, 20.27 ): (a) \(\left[\mathrm{Ru}(\mathrm{py})_{3} \mathrm{Cl}_{3}\right]\) (b) \(\left[\mathrm{Ru}(\mathrm{bpy})_{2} \mathrm{Cl}_{2}\right]^{+}\) (c) \(\left[\mathrm{Ru}(\mathrm{tpy}) \mathrm{Cl}_{3}\right]\)
Problem 22
One isomer of \(\left[\mathrm{PdBr}_{2}\left(\mathrm{NH}_{3}\right)_{2}\right]\) is unstable with respect to a second isomer, and the isomerization process can be followed by IR spectroscopy. The IR spectrum of the first isomer shows absorptions at 480 and \(460 \mathrm{cm}^{-1}\) assigned to \(v(P d N)\) modes. During isomerization, the band at \(460 \mathrm{cm}^{-1}\) gradually disappears and that at \(480 \mathrm{cm}^{-1}\) shifts to \(490 \mathrm{cm}^{-1}\). Rationalize these data.
Problem 24
(a) In each of the following complexes, determine the overall charge, \(n,\) which may be positive or negative: \\[ \begin{array}{l} {\left[\mathrm{Fe}^{\mathrm{II}}(\mathrm{bpy})_{3}\right]^{n},\left[\mathrm{Cr}^{\mathrm{III}}(\mathrm{ox})_{3}\right]^{\prime \prime},\left[\mathrm{Cr}^{\mathrm{III}} \mathrm{F}_{6}\right]^{n},\left[\mathrm{Ni}^{\mathrm{II}}(\mathrm{en})_{3}\right]^{\prime \prime},} \\ {\left[\mathrm{Mn}^{11}(\mathrm{ox})_{2}\left(\mathrm{OH}_{2}\right)_{2}\right]^{\prime \prime},\left[\mathrm{Zn}^{11}(\mathrm{py})_{4}\right]^{n},\left[\mathrm{Co}^{111} \mathrm{Cl}_{2}(\mathrm{en})_{2}\right]^{n}}\end{array}\\] (b) If the bonding in \(\left[\mathrm{MnO}_{4}\right]^{-}\) were \(100 \%\) ionic, what would be the charges on the Mn and \(\mathrm{O}\) atoms? Is this model realistic? By applying Pauling's electroneutrality principle, redistribute the charge in \(\left[\mathrm{MnO}_{4}\right]^{-}\) so that \(\mathrm{Mn}\) has a resultant charge of +1 What are the charges on each 0 atom? What does this charge distribution tell you about the degree of covalent character in the Mn-O bonds?
Problem 25
(a) Which of the following octahedral complexes are chiral: \(\operatorname{cis}-\left[\mathrm{CoCl}_{2}(\mathrm{en})_{2}\right]^{+},\left[\mathrm{Cr}(\mathrm{ox})_{3}\right]^{3-},\) trans \(\left[\mathrm{PtCl}_{2}(\mathrm{cn})_{2}\right]^{2+},\left[\mathrm{Ni}(\mathrm{phen})_{3}\right]^{2+},\left[\mathrm{RuBr}_{4}(\mathrm{phen})\right]^{-},\) cis- \(\left[\mathrm{RuCl}(\mathrm{py})(\mathrm{phen})_{2}\right]^{+} ?\) (b) The solution \(^{31}\) P NMR spectrum of a mixture of isomers of the square planar complex \(\left[\mathrm{Pt}(\mathrm{SCN})_{2}\left(\mathrm{Ph}_{2} \mathrm{PCH}_{2} \mathrm{PPh}_{2}\right)\right]\) shows one broad signal at \(298 \mathrm{K} .\) At \(228 \mathrm{K},\) two singlets and two doublets \((J=82 \mathrm{Hz})\) are observed and the relative integrals of these signals are solvent-dependent. Draw the structures of the possible isomers of \(\left[\mathrm{Pt}(\mathrm{SCN})_{2}\left(\mathrm{Ph}_{2} \mathrm{PCH}_{2} \mathrm{PPh}_{2}\right)\right]\) and rationalize the \(\mathrm{NMR}\) spectroscopic data.
