MOLYBDENUM(IV)-PORPHYRIN DERIVATIVES - OXO(5,10,15,20-TETRA-PARA-TOLYLPORPHYRINATO)MOLYBDENUM(IV), MOO(TTP), AND DICHLORO(5,10,15,20-TETRA-PARA-TOLYLPORPHYRINATO)MOLYBDENUM(IV), MO(CL)2(TTP) - SYNTHESES AND STRUCTURES

Reaction of gaseous hydrogen chloride with the oxomolybdenum(IV) porphyrin complex MoO(TTP) under mild conditions affords the corresponding dichloromolybdenum(IV) complex Mo(Cl)2(TTP), where TTP is the dianion of 5, 10, 15, 20-tetra-p-tolylporphyrin. The molecular stereochemistry of both compounds has been determined by X-ray diffraction techniques using counter data. Crystal data are as follows. Compound I: MoO(TTP), monoclinic, space group P21/c, Z=4, a=17.420 (6) Å, b=16.851 (6) Å, c=15.734 (5) Å, β=112.23 (4)°, Compound II: Mo(Cl)2(TTP), orthorhombic, space group Fdd2, Z=16, a=45.159 (9) Å, b=35.671 (7) Å, c=11.199 (3) Å. Refinement of compound I was based on 2859 observed data; the final discrepancy indices were R1=0.069 and R2=0.084. The molybdenum atom is pentacoordinated by the four pyrrole nitrogen atoms and the apical oxygen atom. The Mo-O bond length is 1.656 (6) Å and the average Mo-N bond distance is 2.110 (6) Å. The molybdenum atom lies 0.6389 (8) Å out of the mean plane of the four nitrogen atoms toward the oxygen atom. The porphyrin shows a slight doming characteristic of five-coordinate metalloporphyrins. Refinement of compound II was based on 1977 observed data; the final discrepancy indices were R1=0.053 and R2=0.063. The molybdenum atom is hexacoordinated by the four pyrrole nitrogen atoms and two chlorine atoms. The average Mo-N bond length is 2.074 (6) Å. The two chlorine atoms are mutually trans with regard to the porphyrin, and the Cl(1)-Mo-Cl(2) bond angle is equal to 178.4 (2)°. Although chemically equivalent, the two Mo-Cl distances appear to be somewhat different: Mo-Cl(1)=2.347 (4) Å, Mo-Cl(2)=2.276 (4). Å. The porphyrin skeleton is planar within experimental error and contains the molybdenum atom. Internal parameters of the porphyrin correspond to an expanded core like that found in Sn(Cl)2(TTP). © 1979, American Chemical Society. All rights reserved.