1,3‐Diphenylpropane‐1,3‐diamines, V: ¹H‐NMR‐ and IR‐Spectroscopic Data of 1,3‐Diphenylpropane‐1,3‐diamines and their Pt(II) Complexes: Stereochemical Assignments and Binding Mode of the Non‐amine Ligands

Abstract

The 'H-NMR spectra of some 1,3-diacetamino-l.3diphenylpropanes and of the dichloro-Pt(II) complexes of the corresponding diamines are compared with their simulated spectra leading to the stereochemical assignments meso / ruc and eryrhrolthreo, respectively.-IR-spectra data of our "diaqua/sulfato complexes" indicate coordinated as well as free (counterionic) sulfate.'H-NMR-und IR-spektroskopische Untersuchungen an 1,3-Diphenylpropan-1,3-diaminen und lhren Pt(I1)-Komplexen: Stereochemische Zuordnung und Bindung der nicht-aminischen Liganden Die 'H-NMR-Spektren einiger 1,3-Diphenylpropan-l,3-diamine und ihrer Dichlor-Pt(l1)-Komplexe wurden mit den berechneten Spektren verglichen und fiihrten so zu den stereochemischen Zuordnungen meso / ruc bzw. erythro/threo.-Die IR-spektroskopischen Daten unserer "diaqua/sulfato Komplexe" weisen auf koordiniertes und freies (gegenionisches) Sulfat in diesen Verbindungen hin.In part 111') of this series we have reported on the syntheses of the title ligands, while part IV2) deals with the preparation of their Pt(1l) complexes with C1', I, SOj2., and water as additional 1igands.-The 'H-NMR spectra of the ligands and their F't complexes have been compiled in the Experimental Parts of these publications, and the ligands were assigned meso / ruc, and eryrhrolthreo, respectively, without giving an explanation for these indications.Here we describe the arguments of these assignments based on 'H-NMR measurements. Because we are dealing with complicated spin systems with various nuclei, the assignment of the protons by conventional methods is difficult in most cases. Therefore, we have simulated the spectra with the help of a Comparex 8/85 computer (system VM/CMS 5.0) using the program LAME (LAOCOON with Magnetic Equivalence). This is a variation of LAOCOON3) modified by Haigh, Swansea College, Knorr, Munchen, and Poppinger and Vollmerhaus-Koschnik, Regensburg (unpublished). LAME considers nuclei of spin 1/2 only and maximally accepts seven groups of magnetically equivalent spins. If one or several of these groups contain more than one spin, there are additional limitations.At first LAME calculares a theoretic spectrum with line frequences and line itensities in a non-iterative run, using a set of estimated chemical shifts and J-values. In most cases this spectrum does not yet fit the observed one. So, in an iterative run the frequence of a line of the experimental spectrum is attributed to the number of each calculated line. This step is decisive for a good result and, therefore, the lines are attributed according to Hoffmunn et u/!). The subsequent calculation is based on the *) Dedicated to Prof. Dr. H. J . Roth, Tiibingen, on the occasion of his 65th birthday.assumption, that the set of parameters is the best one "which make the sum of the squared residuals of the observables (in this case, transition frequencies) a minim~m"~). k: number of observed linesVeXp -fcalc): difference of frequencies between observed and calculated transition LAME then looks for alterations of those parameter...

Synthesis, Cytotoxicity, and DNA Interactions of New Cisplatin Analogues Containing Substituted Benzimidazole Ligands

“…29 In some cases, cis-dichloro complexes show only one band due to low resolutions independent from cis or trans-configurations. 30 Although no shoulder was apparently observable at the Pt-Cl stretching band of the compounds 1-6, the broad nature of the band suggested the presence of the bands overlapped in this domain. In addition, the position of the ν (Pt-Cl) bands of the complexes was at ∼325 cm -1 and the geometry can be assigned as cis.…”

“…It is well-known that cis -dichloro complexes should show two bands of medium intensity because the vibrations are additive, but in a lot of cases the second band is only a shoulder . In some cases, cis- dichloro complexes show only one band due to low resolutions independent from cis or trans-configurations . Although no shoulder was apparently observable at the Pt−Cl stretching band of the compounds 1 − 6 , the broad nature of the band suggested the presence of the bands overlapped in this domain.…”

Factors Influencing the Configuration and Conformation of Diamine Chelate Rings in Platinum(II) Compounds: 2,4-Bis(methylamino)pentane Complexes

“…Investigations of substituted six-membered chelate rings (e.g., meso and racemic [PtCl 2 (1,3-diphenyl-1,3-diaminopropane)] and the 3-hydroxyphenyl analog ) led to the chair conformation with equatorial arrangement of the phenyl rings being favored in the meso form of the complex and interconverting chair conformations with equatorial/axial phenyl rings (with the intermediacy of a favored skew conformation with both phenyl rings oriented equatorially) in the racemic form. A six-membered chelate ring formed by DAP and platinum (e.g., meso and racemic [Pt(2,2‘-bipyridine)(DAP)] 2+ ) was also found to prefer the chair conformation with equatorial arrangement of the methyl groups in the meso form; however, a 70:30 conformer distribution (with the skew conformation having both C -Me's equatorial predominating over the chair conformation having equatorial/axial methyl groups) was found in the racemic form …”