Reactions of [14]annulene and dehydro[14]annulene with organotricarbonylchromium complexes: crystal and molecular structures of hexacarbonyl-trans-6a,12a-dihydro-octalenedichromium(), tricarbonyl-1,4-dihydrophenanthrenechromium(0), and tricarbonylphenanthrenechromium(0)

Abstract

The crystal structures of the title compounds have been determined from X-ray diffractometer data by Patterson and Fourier methods. Hexacarbonyl-trans-6a,12a-dihydro-octalenedichromium(0), (I), triclinic, space group P, Z= 1, a= 11·33(1), b= 7·10(1), c= 9·67(1)Å, α= 102·1(1), β= 135·1(1), γ= 100·1(1)°.

Tricarbonyl-1,4-dihydrophenanthrenechromium(0), (II), monoclinic, space group P2₁/n, Z= 4, a= 8·649(3), b= 12·256(6), c= 10·915(4)Å, β= 95·4(1)°. Tricarbonylphenanthrenechromium(0), (III), monoclinic, space group P2₁/c, Z= 4, a= 8·64(4), b= 11·69(4), c= 13·95(5)Å, β= 101·8°. The structures were refined by least squares to R 0·103 [(I). 693 reflections], 0·084 [(II), 1456 reflections], and 0·050 [(III), 1898 reflections].

(I) has C_i symmetry with two Cr(CO)₃ moieties bound to the triene fragments of the dihydro-octalene ring. In (II) the Cr(CO₃) is symmetrically bound to a benzene fragment of 1,4-dihydrophenanthrene. The results for (III) are compared with those obtained for an orthorhombic modification.