The crystal and molecular structure of vanadyldeoxophylloerythroetioporphyrin-1,2-dichloroethane solvate: an analogue of chlorophyll

Abstract

Single crystals of vanadyl deoxophylloerythroetioporphyrin-l,2-dichloroethane solvate, C32H34N4VO. C2H4CIE, were grown by a vapor-phase diffusion technique. Pertinent crystal data are: space group P21/a, a= 17.963 (3), b= 13.961 (1), c= 14"090 (3)/~,/~= 116.97 (1) °, Z=4. The structure was solved by locating the position of the vanadium atom from a three-dimensional Patterson map and calculating successive Fourier series to locate the remaining atoms. A difference map revealed positions for 28 of the 38 hydrogen atoms, and these were used in the refinement procedure. Full-matrix leastsquares calculations gave a final weighted R of 5.5% for approximately 2000 observed and unobserved reflections. The intelesting feature of this molecule is the effect of the fifth isocyclic ring, E, on the porphyrin skeleton. Results indicate that this ring introduces strain into the molecule and causes distortions in the bond angles and most likely causes a shortening of the V-N bond to the ring C atom from an average of 2.10 A for the other three V-N bonds to 1.96/~ for the shortened bond. The carbon and nitrogen atoms of the porphyrin skeleton are relatively planar and the vanadium atom lies 0"48 A out of the plane of the four nitrogen atoms.

High-Purity Vanadyl Petroporphyrins: Their Aggregation and Effect on the Aggregation of Asphaltenes

“…Porphyrins generally are able to self-associate to form dimers through π–π stacking ,− but can also be bridged by ligands, undergo metal–metal interactions or metal-peripheral interactions, or utilize dipole–dipole interactions, if those groups are present in the periphery. A porphyrin dimer where the macrocycles are stacked directly on top of each other, generally at a distance of 3.3–3.5 Å, ,,,, is known as a H-type aggregate, while an interaction between a peripheral group and the porphyrin macrocycle or metal forms a J-type aggregate. ,,, J-type aggregation has a tendency to occur when porphyrins have functionalized side chains . H-type aggregation can extend beyond dimers into long-range stacks for simple planar porphyrins (such as nickel octaethylporphyrin, or OEP-Ni). ,− Small-angle neutron scattering (SANS) allows fairly detailed characterization of the shape and structure of the nanoaggregates, in addition to the size distribution. , …”

“…Porphyrins generally are able to self-associate to form dimers through π−π stacking 71,90−92 but can also be bridged by ligands, 93 undergo metal−metal interactions or metal-peripheral interactions, 76 or utilize dipole−dipole interactions, if those groups are present in the periphery. A porphyrin dimer where the macrocycles are stacked directly on top of each other, generally at a distance of 3.3−3.5 Å, 78,80,82,86,94 is known as a H-type aggregate, while an interaction between a peripheral group and the porphyrin macrocycle or metal forms a J-type aggregate. 71,75,90,92 J-type aggregation has a tendency to occur when porphyrins have functionalized side chains.…”

Geochemistry of porphyrins: biological, industrial and environmental aspects

“…1), the source of the other less abundant CAPs, including (g) 15,17-propanoporphyrins (CAP6) and (h) 15,17-butanoporphyrins (CAP7), is still a subject of debate. The structures of VO(DPEP) [16,17], VO(13-HCAP6 3'ÀMe ) [18] and (e) nickel(II) deoxophylloerythrin, Ni(DPE), as methyl ester [19] have been confirmed by X-ray crystallography.…”

Axial Coordination in Nickel and Vanadium Porphyrins: Transient and Difference Raman Spectroscopy

“…The vanadium atom is displaced 0.5 Â out of the mean porphyrin plane toward the doubly bound oxygen (17,18). The porphyrin core size (center-tonitrogen distance) is 2.03-2.07 Â (17,18). In non-coordinating solvents the VO porphyrins maintain this geometry and state of axial ligation.…”

“…Vanadium in geoporphyrins exists exclusively in the V(IV) valence state as the vanadyl ion (VO ) with the oxo atom bound axially. The vanadium atom is displaced 0.5 Â out of the mean porphyrin plane toward the doubly bound oxygen (17,18). The porphyrin core size (center-tonitrogen distance) is 2.03-2.07 Â (17,18).…”