Dinuclear organoplatinum(II)-methyldiphenylphosphine complexes of nicotinic acid

Crisp, Michael Gerard; Pyke, Simon M.; Rendina, Louis M.

doi:10.1016/s0022-328x(00)00375-2

Cited by 12 publications

(8 citation statements)

References 46 publications

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“…The 31 P{ 1 H} NMR spectra of 3 and 4 display a singlet resonance that is flanked by 195 Pt ( I = 1/2; abundance = 33.8%) satellite signals for the equivalent trans -PPh 3 ligands at δ 22.0 ( 1 J PPt = 3024 Hz) and δ 21.4 ( 1 J PPt = 3021 Hz), respectively. The chemical shifts of the resonances and the magnitude of the Pt−P coupling constants are comparable to those reported for other σ -arylplatinum(II) complexes with mutually trans PPh 3 ligands. 4a,, The 195 Pt{ 1 H} NMR spectra of 3 and 4 show the expected triplet resonances at δ −4732 and −4700, respectively, with 1 J PtP within experimental error of those reported above.…”

Section: Resultssupporting

confidence: 84%

“…Each of the complexes displayed a peak at m / z 963 attributed to [M − OTf] + . Furthermore, peaks at m / z 840 and 719 were also detected, and they are most likely attributed to the loss of nicotinic acid followed by the loss of the σ -aryl ligand from the parent platinum(II) species, a feature that has been reported previously for related complexes …”

Section: Resultssupporting

confidence: 66%

“…In this work, the wide applicability of a silyl ester protection/deprotection methodology will be demonstrated by the preparation of several types of cationic organoplatinum(II) complexes with carboxylic acid functionality from a platinum(0) precursor, some of which are isomeric with those reported previously 4a. To the best of our knowledge, this approach has not been previously employed for an oxidative addition reaction in transition metal chemistry.…”

Section: Introductionmentioning

confidence: 99%

“…Although the coordinate-covalent bond is an efficient and versatile motif for the construction of molecular polygons and polyhedra, its combination with the hydrogen bond is an alternative approach for the assembly of discrete macrocyclic entities containing transition metal centers. By using coordinate-covalent bonds to afford tectons (building blocks) of appreciable size and the highly directional hydrogen bond as a means of controlling the self-assembly process, hybrid molecular polygons are feasible. , …”

Section: Introductionmentioning

confidence: 99%

“…Recently, we have shown that dinuclear organoplatinum(II) tectons with hydrogen-bonding functionality can be programmed to self-assemble into dimeric and trimeric macrocycles in CD 2 Cl 2 solution at 298 K 4a. The synthetic methodology that was employed in the preparation of the complexes consisted of a well-known double oxidative addition reaction of an aryl di-iodide to a platinum(0) species, followed by triflate metathesis of the iodo ligands in the resulting diplatinum(II) product and, finally, the addition of a N-donor ligand containing the hydrogen-bonding functionality, e.g., nicotinic acid, to the diplatinum(II)-triflato species . In principle, one could prepare platinum tectons that are isomeric to those described previously by employing an aryl iodide with hydrogen-bonding functionality in the oxidative addition reaction and by using a suitable N-donor ligand to bridge the two platinum(II) centers after triflate metathesis.…”

Section: Introductionmentioning

confidence: 99%

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A New Methodology for the Preparation of Cationic Organoplatinum(II) Complexes with Hydrogen-Bonding Functionality

2001

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A new methodology for the preparation of two series of cationic organoplatinum(II) complexes with hydrogen-bonding functionality is described. The mononuclear complexes of the type trans-[Pt(σ-aryl)L(PPh 3 ) 2 ]OTf (L ) nicotinic acid, aryl ) C 3 -benzoic acid (9) or C 4 -benzoic acid (10); L ) isonicotinic acid, aryl ) C 3 -benzoic acid (11) or C 4 -benzoic acid (12); OTf ) trifluoromethanesulfonate (triflate)) constitute the first series, and the dinuclear complexes of the type trans- [Pt(σ-aryl) 23) or C 4 -benzoic acid ( 24)) constitute the second series. The methodology described here involves the protection of the carboxylic acid group of a 3-or 4-iodobenzoic acid precursor as the tert-butyldiphenylsilyl ester, followed by an oxidative addition reaction of the C-I bond with the Pt(0) species Pt(PPh 3 ) 4 to yield the key (σ-aryl)iodoplatinum(II) intermediates 3 and 4, the structures of which were determined by X-ray crystallography. Subsequent treatment of these products with AgOTf, followed by the addition of a suitable monodentate or bridging bidentate N-donor ligand and, finally, facile removal of the silyl protecting group-(s) with HOTf affords the target complexes with hydrogen-bonding functionality in high yield. Variable-temperature 1 H NMR experiments with the silyl-protected complexes trans-[Pt(σ-aryl)L(PPh 3 ) 2 ]OTf (aryl ) C 3 -tert-butyldiphenylsilyl benzoate, L ) nicotinic acid (5) or isonicotinic acid (7)) confirm that a dynamic intramolecular process involving the pyridyl ligand is occurring. The rotational barrier of a pyridyl ligand in an organoplatinum(II) complex is reported for the first time, where ∆G q ) 48.3 ( 0.9 and 45.7 ( 0.9 kJ mol -1 for complexes 5 and 7, respectively.

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Section: Resultssupporting

confidence: 84%

Section: Resultssupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%