ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Crystals of 1,2,3,4-tetramethylcyclobutadiene-nickel dichloride, C8H12NiCl2, are monoclinic, a = 16,01, b = 8,01, c = 16,45 Å; β = 111° 5′; Z = 8; Space group P21/n. Crystals of the benzene containing solvate, 2C8H12NiCl2, C6H6, lose benzene rapidly but are stable for several days when enclosed in glass tubes. The unit cell of the solvate is monoclinic, a = 8,311, b = 11,944, c = 12,715 Å; β = 103° 2′; space group P21/c; it contains 4 molecules of complex plus 2 molecules of benzene. The approximate structure has been derived by standard methods and refined by least-squares analysis to an R factor of 0,069. The molecule, as it exists in the solvate, is a dimer, C8H12Ni2Cl4C8H12. Each Ni atom has on one side the four atoms of the cyclobutadiene ring (Ni-C, 2,00 to 2,05 Å), and on the other side 3 Cl neighbours, two shared with the second Ni to form a 4-membered ring (Ni-Cl, 2,35 Å) and one unshared (Ni-Cl, 2,26 Å). The cyclobutadiene ring is planar and appears to be square or very nearly so (C-C, 1,40 to 1,45 Å). The methyl groups are displaced outwards (i.e. away from the Ni atom) by 0,12 to 0,19 Å, probably as a result of steric interference with the Cl atoms. The benzene rings lie between, and approximately parallel to, pairs of C8H12 groups belonging to different molecules, and undergo a strong rotational disorder in their own planes.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19620450231
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