| The gas-phase formation of transition-metal carbonyl complexes containing arsenic and antimony multiple bonds is reported. Using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR), As2- and Sb2- reacts with the mononuclear metal carbonyls of Cr, Mo, W, Fe, the cyclopentadienyl carbonyl complexes of Mn and Co, and CO(CO)3NO. The diarsenide(-1) and diantimonide(--1) ions are formed by laser ablation of the elements, subsequent electron capture, and isolation within the ion cyclotron cell. The reaction of mononuclear metal carbonyls with As2-- and Sb2 - form the multiple bond complexes, M(CO)4E - (for Group 6 metals) or Fe(CO)3E- (E = As or Sb), which contain metal-pnictide multiple bonds. The reaction of CpCo(CO)2 with As2- and Sb2- results in the formation of CpCoAs - and CpCoSb-, which are the first reported examples of naked cobalt-pnictide multiple bonds and the first triple bond to Co. Additionally, reactions of CpMn(CO)3 and MeCpMn(CO) 3 with AsO- and SbO- were found to form CpMn(CO)2E- and MeCp(CO) 2E-, respectively, along with loss of CO2 . The reaction of Co(CO)3NO with As2-- and Sb2- forms highly reactive intermediates that subsequently react to form clusters of the general form, Cox(NO) y(CO)zE- (x = 1-2, y = 0--2, z = 1--4). AsO- and SbO- are intermediate reactants formed from the reaction of As2- and Sb2- with oxygen or water, or from residual surface oxides. Selective isotopic ejection and isolation of reactants, product and intermediates, made it possible to obtain a detailed picture of the product-formation mechanisms. The electronic properties and structure are studied with Density Functional Theory methods. |
