| This study focuses on the coordination chemistry observed in the reactions of dinuclear molybdenum(II) carboxylate compounds with nitrogen donor ligands and discusses the potential biological application of the resulting complexes. All compounds were synthesized from (MO{dollar}rmsb2(Osb2CR)sb2(MeCN)sb6rbracklbrack BFsb4rbracksb2{dollar} (R = CH{dollar}sb3{dollar} and CHF{dollar}sb2){dollar} starting materials. Products include a "trimer-of-dimers", {dollar}rm Mosb6(Osb2CCHFsb2)sb{lcub}12{rcub}(bpy)sb4{dollar} (bpy = 2,2{dollar}spprime{dollar}-bipyridine), in which three dinuclear units are joined via axial difluoroacetate bridges. In addition, a novel "dimer-of-dimers" compound, {dollar}rmlbrack Mosb4(Osb2CCHFsb2)sb4{dollar}(1,2-bis(5{dollar} spprime{dollar}-methyl-2,2{dollar}spprime{dollar}-bipyridin-5-yl)ethane){dollar} sb2rbracklbrack BFsb4rbracksb4,{dollar} in which two dinuclear units are bridged via equatorially bound tetradentate chelating ligands has been structurally characterized. The related dinuclear and polymeric products, {dollar}rmlbrack Mosb2(Osb2CCHFsb2)sb2(bpy)sb2(MeCN)(BFsb4)rbracklbrack BFsb4rbrack{dollar} and {dollar}rmlbrack Mosb4(Osb2CCHFsb2)sb8(bpy)sb2rbracksb{lcub}n{rcub},{dollar} have also been isolated and characterized.; A synthetic and electrochemical study of a series of compounds with the general formula {dollar}rmlbrack Mosb2(Osb2CR)sb2{dollar}(N-N){dollar}sb2rbracklbrack {lcub}rm BF{rcub}sb4rbracksb2{dollar} (N-N = bpy, 4,4{dollar}spprime{dollar}-Me{dollar}sb2{dollar}bpy, 5,5{dollar}spprime{dollar}-Me{dollar}sb2{dollar}bpy, and 1,10-phenanthroline; R = CH{dollar}sb3,{dollar} CHF{dollar}sb2,{dollar} and Ph) was initiated to probe the reactivity of the dinuclear system. Extended Huckel Theory calculations were performed to determine the nature of the orbitals populated upon reduction of the dinuclear system. The rich reduction chemistry of these compounds is unusual in that four reduction waves were observed. The first two reversible reductions were determined to be primarily ligand-based processes but with {dollar}sim{dollar}30% metal contribution.; Compounds with the tridentate ligands 1,4,7-triazacyclononane (TACN) and tris-pyrazolylborate (HB(pz){dollar}sb3sp-){dollar} were prepared and crystallographically characterized. {dollar}rmlbrack Mosb2(OAc)sb2(TACN)(MeCN)sb2rbracklbrack BFsb4rbracksb2, lbrack Mosb2(OAc)sb2(TACN)(bpy)rbracklbrack BFsb4rbracksb2, and lbrack Mosb2(OAC)sb2(HB(pz)sb3)(bpy)rbracklbrack BFsb4rbrack{dollar} represent unusual examples of quadruply bonded compounds with only one facially coordinated ligand. These complexes are interesting coordination compounds that also serve as models for the interaction of dinuclear metal centers with nitrogen-donating amino acid side chains.; Unusual coordination modes have been observed for the purine nucleobase derivatives, 9-ethylguanine, 9-ethyladenine, and 1,9-diethyladenine, in which the ligands bridge the dinuclear molybdenum centers via the X6,N7 positions (X = O, N). The resultant compounds, {dollar}rmlbrack Mosb2(Osb2CCHFsb2)sb2{dollar}(9-EtGH){dollar}rmsb2(MeCN)sb2rbrack lbrack BFsb4rbracksb2, lbrack Mosb2(Osb2CCHFsb2)sb2{dollar}(9-{dollar}rm EtAH)sb2(MeCN)sb2rbracklbrack BFsb4rbracksb2,{dollar} and {dollar}rmlbrack Mosb2(OAc)sb2{dollar}(1,9-{dollar}rm Etsb2A)sb2rbracklbrack Irbracksb2{dollar} have been characterized by variable temperature {dollar}sp1{dollar}H NMR, IR, and UV-vis spectroscopies as well as by X-ray diffraction and elemental analysis. These complexes provide models for the potential in vivo interactions of dinuclear carboxylate compounds with DNA. |
