ABSTRACT
The reaction of hexacyanobutadiene (HCBD) and meso-tetrakis(4-chlorophenyl)porphinatomanganese(II) pyridine [MnIITClPPpy] (1Cl) leads to two phases of [MnIIITClPPpy][HCBD].PhMe (alpha-2Clpy, beta-2Clpy). Similarly, the reaction of HCBD and tetrakis(4-bromophenyl)porphinatomanganese(II) pyridine [MnIITBrPPpy] (1Br) leads to two products [MnIIITBrPPpy] [HCBD] * PhMe (2 Brpy) and [MnIIITBrPP][HCBD]*2 PhMe (3Br). The structure of dark-green alpha-2Clpy consists of one porphyrin unit with MnIII in a square pyramidal coordination environment axially bound to one pyridine. The cation forms [MnIIITCIPPpy](2)2+ as cofacial dimerized porphyrins. Each [HCBD]*- is nonplanar with a torsion angle of 170.8(4) degrees about the center C-C bound, and forms [HCBD](2)2- dimers in the solid state with sub-van der Waals contacts of 3.325 and 3.340 angstroms. The magnetic data above 10 K obey the Curie-Weiss expression with a theta of -2.5 K, and mueff (300 K) = 4.91 muB as expected for S=2MnIII and S = 0 [HCBD](2)2-. The magnetic data for alpha-2Clpy can be fit with an zero-field-splitting D of -1.45 K. beta-2 Clpy consists of one porphyrin unit with MnIII in a distorted octahedral coordination environment axially bound to py and to a monodentate [HCBD]*- bound via an exo-nitrile. [HCBD]*- is nonplanar with a torsion angle of 169.7(5) degrees about the center C-C bound. The ueff (350 K) is 5.09 muB; however, the magnetic data do not obey the Curie-Weiss expression above 70 K. The low temperature data may be fit with a theta of -5.4 K. The data was modeled to an isolated S = 2 and S = 1/2 dinuclear spin system with J/kappaB = - 90 K. Decomposition of [HCBD]*- to [C4(CN)5O]- was evidenced by the determination of the structure of [MnIIITCIPP][C4(CN)5O] 2PhMe (3ClO). Crystals of 3 Cl-O were prepared by reaction of HCBD and 1Cl in the presence of a drop of water. The molecular structure consists of [HCBD]*-trans-mu-N-2,3-bound to [MnIIITBrPP]+ forming a 1-D coordination polymer of alternating [MnIIITBrPP]+ and [HCBD]*-. The intrachain Mn***Mn distance was 10.675(3) angstroms, with important interchain Mn***Mn distances of 10.832, 11.016, and 14.696 A. The magnetic data were fit to a Curie-Weiss law (10 < T< 290 K) with a theta of -3.5 K, and D = 0.3 K with mueff = 4.97 muB at 300 K.
