Solid‐State Photochemical [2+2] Cycloaddition in a Hydrogen‐Bonded Metal Complex Containing Several Parallel and Crisscross CC bonds

Abstract

One-dimensional hydrogen-bonded complex [Zn(bpe)(2)(H(2)O)(4)](NO(3))(2).8/3 H(2)O.2/3 bpe (1, bpe=4,4'-bipyridylethylene) containing coordination complex cations [Zn(bpe)(2)(H(2)O)(4)](2+) with parallel and crisscross double bonds undergoes photochemical [2+2] cycloaddition in the solid state and produces tetrakis(4-pyridyl)cyclobutane (tpcb) in up to 100 % yield with rctt-tpcb (2a) as major and rtct-tpcb (2b) as minor product. The bpe ligands with crisscross conformation of C=C bonds appear to undergo pedal-like motion prior to photodimerization. Grinding single crystals to powder accelerates the pedal motion of crisscrossed olefins in the bpe ligands to parallel alignment and provides the rctt-cyclobutane stereoisomer 2a quantitatively. In addition, 100 % photodimerization of ground 1 indicates that the free bpe ligands, which are remote from each other in a pool of water, and NO(3)(-) ions moved toward each other to give a mixture of rctt- and rtct-tpcb isomers.

Exploitation of knowledge databases in the synthesis of zinc(II) malonates with photo-sensitive and photo-insensitive N,N′-containing linkers

“…Powder X-ray diffraction confirmed that the samples were phase pure and consisted mainly of the above reaction products (see supporting information). Single-crystal XRD confirmed the validity of our proposal about possible Zn (Table S3) and have the same underlying net; however, the networks of (7) and (9) (Peedikakkal & Vittal, 2008), it readily undergoes the [2 + 2] cycloaddition 0D!1D photoreaction to give a coordination polymer (see x2.4 for details).…”

“…We consider the insufficient investigation of photoinitiated reactions a result of the factors that govern the mutual disposition of reactive fragments, which are not well understood. With regards to metal complexes, mainly hydrogen bonds (Peedikakkal & Vittal, 2008) and metallophilic interactions (Georgiev et al, 2010;Chu et al, 2005;Schmidbaur & Schier, 2012) were used to carry out 0D!1D transformations, or in some cases, planar chelate (Papaefstathiou et al, 2004(Papaefstathiou et al, , 2005 and bridging (Mir et al, 2010;Sato et al, 2012;Nagarathinam & Vittal, 2006;Chanthapally et al, 2013;Toh et al, 2005) carboxylate anions were applied to fix the photo-sensitive species in reactive positions for intramolecular 1D!1D or 2D!2D reactions. For example, 1D coordination polymers with ladder-type structures are characterized by close and parallel orientation of the double bonds in photoreactive spacer ligands (depicted in black in Fig.…”

“…To summarise, there is a high probability of two-and threeperiodic ladder architectures with parallel orientation of ethenyl groups in Zn The validity of above approach is verified by the fact that a number of previously obtained zinc(II) dicarboxylates containing 4,4 0 -bipyridine and its analogues are characterized by the above CFs and have one of the proposed topologies (Table S2). Moreover, a number of zinc(II) nitrate (Peedikakkal & Vittal, 2008), monocarboxylate (Toh et al, 2005;Chanthapally et al, 2014) or dicarboxylate (Mir et al, 2010;Sato et al, 2012;Ou et al, 2011Ou et al, , 2012Hu et al, 2015) …”

Metal-Organic Frameworks for Photochemical Reactions

“…Complex Containing Several Parallel and Crisscross C═C Bonds Metal-Organic Frameworks for Photochemical Reactionsmolecules in the equatorial sites [31]. A few guest bpe molecules were also found in the lattice along with lattice water.…”

Bimolecular Photoreactions in the Crystalline State

“…As with the other examples, optical microscopy revealed that the transparency and shape of the crystals along with their singlecrystal nature were retained during the photoreaction, which suggested that the reaction occurred via an SCSC transformation. Final example of metalion -induced photodimerization is the coordination complex [Zn(bpe) 2 109 Interestingly, even this coordination complex forms parallel and crisscross double bonds, which undergoes photochemical [2 + 2] cycloaddition in the solid state and produces rctt -tetrakis(4 -pyridyl)cyclobutane in up to 100% yield of photodimers with rctt -tpcb as major and rtct -tpcb as minor…”