Selecting topology and connectivity through metal-directed macrocyclization reactions: a square planar palladium [2]catenate and two noninterlocked isomers.

We report the synthesis of a [2]catenate using a square planar palladium(II) template, together with two isomers of the interlocked structure: a single tetradentate macrocycle that adopts a "figure of eight" conformation to encapsulate the metal and a complex in which the two macrocycles of the catenane are not interlocked. The three isomers can each be selectively formed depending on how the building blocks are assembled and cyclized. Olefin metathesis of both building blocks while they are attached to the metal gives the single large macrocycle in 77% yield. Cyclizing the monodentate unit prior to attaching both ligands to the metal gives the [2]catenate in 78% yield. Preforming the tridentate macrocycle produces a complex in two atropisomeric forms-threaded and nonthreaded-in a 2:3 ratio, which do not interconvert in dichloromethane at room temperature over 7 days. RCM of the nonthreaded atropisomer affords the complex with two noninterlocked macrocyclic ligands; RCM of the threaded atropisomer generates the topologically isomeric [2]catenate. Heating the acyclic atropisomers in acetonitrile provides a mechanism for their interconversion via ligand exchange, allowing the threaded:nonthreaded ratio to be varied from 2:3 to 8:1. All three fully ring-closed complexes were characterized unambiguously by 1H NMR spectroscopy and X-ray crystallography. As far as we are aware, this is the first time such a set of three formal topological and constitutional isomers has been described.

[1]  G. Bernardinelli,et al.  Formation of the First Isomeric [2]Catenates by Self‐Assembly about Two Different Metal Ions , 1995 .

[2]  V. Sokolov.  Topological Ideas in Stereochemistry , 1973 .

[3]  T. Takata,et al.  Synthesis of novel interlocked systems utilizing a palladium complex with 2,6-pyridinedicarboxamide-based tridentate macrocyclic ligand , 2004 .

[4]  Joseph W. Ziller,et al.  A Series of Well‐Defined Metathesis Catalysts–Synthesis of [RuCl2(CHR′)(PR3)2] and Its Reactions , 1995 .

[5]  Jean-Pierre Sauvage,et al.  Light-driven machine prototypes based on dissociative excited states: photoinduced decoordination and thermal recoordination of a ring in a ruthenium(II)-containing [2]catenane. , 2004, Angewandte Chemie.

[6]  J. Sauvage,et al.  Construction of Interlocking and Threaded Rings Using Two Different Transition Metals as Templating and Connecting Centers: Catenanes and Rotaxanes Incorporating Ru(terpy)2-Units in Their Framework , 1997 .

[7]  Ralph Weissleder,et al.  Magnetic relaxation switch immunosensors detect enantiomeric impurities. , 2004, Angewandte Chemie.

[8]  J. Sauvage,et al.  Zinc(II)-templated synthesis of a [2]-catenane consisting of a 2,2',6',2' '-terpyridine-incorporating cycle and a 1,10-phenanthroline-containing ring. , 2003, Inorganic chemistry.

[9]  Fabio Arico,et al.  Synthesis of a [2]catenane around a Ru(diimine)3(2+) scaffold by ring-closing metathesis of olefins. , 2003, Organic letters.

[10]  Michael E. Schlesinger,et al.  An oscillation in the global climate system of period 65–70 years , 1994, Nature.

[11]  J. Sauvage,et al.  Templating and Clipping Coordination Reactions Leading to Heteronuclear Trimetallic Complexes Containing Interlocking Rings. , 1997, Inorganic chemistry.

[12]  M. Fujita,et al.  Self-Assembly of [2]Catenanes Containing Metals in Their Backbones , 1999 .

[13]  S. Nguyen,et al.  Artificial Enzymes Formed through Directed Assembly of Molecular Square Encapsulated Epoxidation Catalysts. , 2001, Angewandte Chemie.

[14]  M. Shibasaki,et al.  Enantio- and diastereoselective catalytic Mannich-type reaction of a glycine schiff base using a chiral two-center phase-transfer catalyst. , 2005, Angewandte Chemie.

[15]  J. Sauvage,et al.  A [2]catenane constructed around a Ru(diimine)(3)(2+) complex used as a template. , 2003, Journal of the American Chemical Society.

[16]  S. J. Loeb,et al.  SIMULTANEOUS FIRST- AND SECOND-SPHERE COORDINATION. ORGANOPALLADIUM CROWN ETHER COMPLEXES AS METALLORECEPTORS FOR O-AMINOPYRIDINE DERIVATIVES , 1994 .

[17]  David A Leigh,et al.  Benzylic Imine Catenates: Readily Accessible Octahedral Analogues of the Sauvage Catenates. , 2001, Angewandte Chemie.

[18]  P. Ashton,et al.  Molecular Necklace: Quantitative Self-Assembly of a Cyclic Oligorotaxane from Nine Molecules , 1998 .

[19]  K. Houk,et al.  Insertion of Helium and Molecular Hydrogen Through the Orifice of an Open Fullerene. , 2001, Angewandte Chemie.

[20]  K. Tamao,et al.  Conformation Control of Oligosilanes Based on Configurationally Constrained Bicyclic Disilane Units , 2000 .

[21]  M. Fujita,et al.  Spontaneous assembly of ten components into two interlocked, identical coordination cages , 1999, Nature.

[22]  S. J. Loeb,et al.  Molecular Receptors for Adenine and Guanine Employing Metal Coordination, Hydrogen‐Bonding and π‐Stacking Interactions , 1997 .

[23]  C. Dietrich-Buchecker,et al.  Unexpected synthesis of an 8-shaped macrocycle instead of an interlocking-ring system. , 2000, Inorganic chemistry.

[24]  D. Busch,et al.  Copper(II) Template Synthesis of a 20-Membered [1+1] Schiff Base Macrocycle and Nickel(II) Template Synthesis of a 40-Membered [2+2] Schiff Base Macrocycle from 2,6-Pyridinedicarboxaldehyde and 1,13-Diamino-4,7,10-trioxatridecane , 1997 .

[25]  D. Proserpio,et al.  Novel Networks of Unusually Coordinated Silver(I) Cations: The Wafer-Like Structure of [Ag(pyz)2][Ag2(pyz)5](PF6)3·2G and the Simple Cubic Frame of [Ag(pyz)3](SbF6)† , 1995 .

[26]  Katsuyuki Ogura,et al.  Transition-metal-directed assembly of well-defined organic architectures possessing large voids: From macrocycles to [2] catenanes , 1996 .

[27]  Robert H. Grubbs,et al.  Ring-Closing Metathesis and Related Processes in Organic Synthesis , 1995 .

[28]  M. Fujita,et al.  Quantitative self-assembly of a [2]catenane from two preformed molecular rings , 1994, Nature.

[29]  E. Gil-av,et al.  Temperature Dependent Inversion of Elution Sequence in the Resolution of α‐Amino Acid Enantiomers on Chiral Diamide Selectors , 1989 .

[30]  S. Homans,et al.  Identification of the 5-methylthiopentosyl substituent in Mycobacterium tuberculosis lipoarabinomannan. , 2004, Angewandte Chemie.