QUASI-UNIDIMENSIONAL ([M(DMB)(2)]Y)(N) ORGANOMETALLIC POLYMERS (M=CU(I),AG(I) DMB EQUALS 1,8-DIISOCYANO-P-MENTHANE, Y=BF4-, PF6-, NO3-, CLO4-, CH3CO2-) - STRUCTURAL, CALORIMETRIC, AND LUMINESCENCE PROPERTIES

A series of new organometallic polymers of the type {[M(dmb)(2)]Y}(n) (dmb = 1,8-diisocyano-p-menthane; Y = BF4-, NO3-, ClO4-, M = Cu; Y = B F4-, PF4-, NO3-, CH3CO2-, ClO4-; M = Ag) are reported. These materials have been characterized from single-crystal X-ray diffraction (for {[ Ag(dmb)(2)]Y}(n); Y = BF4-, NO3-, ClO4-), X-ray powder diffraction (wh ich established the isostructurality between M = Cu and Ag and the rel ative crystallinity level), differential scanning calorimetry (DSC), s olid-state magic spinning angle and solution C-13-NMR, and spin-lattic e relaxation time measurements (T-1, C-13-NMR). Three synthesis method s were employed in order to obtain highly crystalline, semicrystalline , and highly amorphous {[Cu(dmb)(2)]BF4}(n) polymers. One polymer has been successfully characterized from a light-scattering technique. For the amorphous {[Cu(dmb)(2)]BF4}(n) polymer, the molecular weights ave raged 160 000. The Ag polymers are found to be rather crystalline and exhibit very low solubility properties. Except for the {[Ag(dmb)(2)]PF 6}(n) and the highly crystalline {[Cu(dmb)(2)]BF4}(n) materials, all p olymers exhibit glass transitions in the 37-96 degrees C (305-340 K) r ange, even if the materials exhibit a very large crystallinity level. The {[M(dmb)(2)]Y}(n) organometallic materials (M = Cu, Ag; Y = BF4-, PF6-, NO3-, CH3CO2-) are also strongly luminescent in the visible rang e (400-600 nm) at 77 K, exhibiting polyexponential emission decay trac es (either in the solid state or in solutions). By comparison with the emission properties of the non-polymeric [M(CN-t-Bu)(4)](BF4) compoun ds (M = Cu, Ag) as a model for a monomeric unit, the first and shea-li ved component of the emission decay traces (30-90% in relative intensi ty) is associated with a higher-energy emission localized at one M cen ter within the polymer (''monomer-like emission''). This is also confi rmed by time-resolved emission spectroscopy from the comparision with the emission maxima. The other components in the polyexponential decay s are associated with lower-energy emissions that are only present in the polymers. This phenomenon is associated with an energy transfer me tal-to-metal delocalized along the M chain somewhat similar to the exc iton phenomenon known in organic solids. The depolarization of the emi ssion Light confirms the phenomenon. From density functional theory ca lculations, the lowest energy excited states have been assigned as MLC T (metal-to-ligand charge transfer) with the HOMO being the M centered d orbitals, and the LUMO being the pi MO centered on the isocyanide groups. X-ray data for {[Ag(dmb)(2)]BF4}(n): space group P2(1)2(1)2(1) , orthorhombic, a 9.3273(18) Angstrom, b = 13.685(2) Angstrom, c = 22. 124(4) Angstrom, V = 2824.0(9) Angstrom(3), Z = 4, D-calc = 1.353 g/cm (3), R = 0.068, R(w) = 0.073. {[Ag(dmb)(2)]-NO3 . 0.70H(2)O}(n): space group P2(1) /c, monoclinic, a = 13.1746(14) Angstrom, b = 9.7475(11) Angstrom, c = 23.207(3) A, beta = 105.15(1)degrees, V = 2876. 5(6) Ang strom(3), Z = 4, D-calc = 1.297 g/cm(3), R = 0.051, R(w) = 0.048. {[Ag (dmb)(2)]ClO4}(n): space group P2(1)2(1)2(1), orthorhombic, a 9.282(2) Angstrom, b = 13.772(2) Angstrom, c = 22.091(3) Angstrom, V = 2824.1( 9) Angstrom(3), Z = 4, D-calc = 1.282 g/cm(3), R = 0.034, R(w) = 0.077 .