CSIR-UGC-NET/JRF GATE CHEMISTRY TEST : ORGANOMETALLIC COMPOUNDS

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1 1 CSIR-UGC-NET/JRF GATE CHEMISTRY TEST : ORGANOMETALLIC MPOUNDS Time 00 : Hour Date : M.M. : 0 INSTRUCTION : 1. There are Two Parts. Part-A contains 10 objective type questions, each question carry 2 marks and Part-B contains 10 objective type questions, each question carry marks. 2. There is negative 2% will be deducted for each wrong answer.. Attempt all the questions, use of calculator is not allowed. PART - A 10 1 CpRh Rh, I, 100% 2. Shows a triplet at C owing to the presence of 1. The carbonyl resonance in 1 C NMR spectrum of (a) Terminal (b) 2 µ (c) µ 2. h Cr NO P Cr NO (d) Cp x The complex P is homoleptic complex and follows 18 electron the value of x will be (a) (b) (c) 0 (d). The cluster Co (a) closo, arachno, nido (c) closo, nido, arachno 1 2, Fe C 1 and Ni. For complex (A) to follow 18 electron rule missing ligand should be Me Me P Mo (A) P C Me Me C 10 having the structure respectively. (b) nido, arachno, closo (d) closo, closo, nido CH (a) C7H8 8 (b) C8H8 7 (c) C7H7 (d) C H. Arrange the following in order of their increasing M C stretching frequency (A) Hf (E) Os 2 2 (B) Ta Ir (a) A < B < C < D < E < F (c) A < B < C < E < D < F (F) W (C) (D) Re (b) F < E < D < C < B < A (d) F < E < D < C < A < B

2 . In the complex Me Al 2 (µ-me) 2, the two alkyl acts as a bridging ligands. This seems to happens by 2e, three centre bond involving between metal and alkyl carbon. The hapticity of terminal and bridging alkyl groups are respectively (a), (b), (c), (d), 7. Consider the metal carbonyl complex (A) q M where q = 2, 1, 0, +1 The strongest C O band in IR spectrum can be observed when the value of q will be (a) 2 (b) 1 (c) 0 (d) Ru 18 2 is isolobal with (a) B 2 H (b) B H (c) Ir (d) Fe Suggest what changes in cluster structure might accompany the reaction: Co N Co N 2 (a) Octahedron to trigonal prism (b) Square pyramid to trigonal bipyramid (c) Tetrahedron to octahedron (d) Trigonal prism to octahedron [Ph C]BF Ph CH BF Mo Mo The oxidation state of Mo in the reactant and product are respectively (a) 0, 1 (b) 1, 1 (c) 0, 0 (d) 2, 0 PART-B 11. CpFe (A) is a dark green solid compound. The IR spectrum shows a single stretching band at 10 cm 1. The 1 H NMR spectrum shows a single line even at low temperature. Which of the following statement is not true on the basis of gien data about the structure of CpFe (a) The complex (A) follows the 18 electron rule. (b) The total number of M M bonds in complex are six. (c) All s are present -mode. (d) Two s are present in µ 2 -mode where as another two s are present at µ modes. 12. Which of the following Molybdenum complex having highest carbonyl stretching frequency (a) Mo PF (b) Mo PCl (c) Mo PClPh 2 (d) Mo PMe

3 1. Match List-A (organometallic compound) with List-B ( 1 H NMR chemical-shift for marked proton) List-A List-B (A) Mn H (I) ppm 2 (B) Ni C2H (C) C H 2 Cr (II).0 ppm (III) 7. ppm CH (D) ( C H ) 2 Ta CH 2 (IV).12 ppm (a) A-III, B-IV, C-II, D-I (c) A-I, B-II, C-III, D-IV 1. The cluster having arachno type structure is (b) A-III, B-II, C-IV, D-I (d) A-II, B-III, C-I, D-IV (a) Ir 12 (b) Rh 1 (c) Os 18 2 (d) Ru C 1 1. A compound A having the composition FeC9H8O shows one signal at 2. ppm and another one around.0 ppm in its 1 H NMR spectrum. The IR spectrum of this compound shows two bands around 1900 and 180 cm 1. The compound follows the 18 electron rule of the following statements for A, the correct one is/are (A) It has Cp group. (B) It has a terminal ligand. (C) It has a CH ligand (D) It has Fe H bond. (a) (A) and (B) only (b) (C) only (c) (A) and (C) only (d) (B) and (D) only. 1. Complexes of general formula, fac-[mo() (phosphine) ] have the C O stretching bands as given below. Phosphines: PF (A); PCl (B); P(Cl)Ph 2 (C); PMe (D) v(), cm 1 : 2090(i); 200(ii); 1977(iii); 19(iv) The correct comibination of the phsphine and the streching frequency is, (a) (A i), (B ii), (C iii), (D iv) (b) (A ii), (B i), (C iv), (D iii) (c) (A iv), (B iii), (C ii), (D i) (d) (A iii), (B iv), (C i), (D ii) 17. Find the best possible combination of metal ligand and charge. So, that the complex (X) follows 18 electron rule. z M L x (a) M Co, L, x, z (b) M Fe, L CN, x, z 2 (c) M Fe, L, x, z 2 (d) M Mn, L PPh, x, z Ti + seldom forms stable carbonyl complexes because * (a) Antibonding orbitals of are high in energy. (b) increases electron density on the metal Ti + (c) The d set of metal t 2g orbtal find no match with the (d) Absence of back bonding as the metal present in highest oxidation state.

4 19. Indenyl is a well know organometallic ligand the structure of indenyl ligand is the haptacity and electron contribution for the indenyl complex [(Indenyl)Fe(Cp)() 2 ] are respectively. (a) 1, 1 (b), 1 (c) 1, (d) 1, Which of the following complex does not obey 18 electron rule. (a) 2 i W H2 P Pr 2 O (b) 2 OsH H P OEt 2 (c) Fe C H C O Fe Cl (d) Rh Rh Cl

5 CSIR-UGC-NET/JRF GATE CHEMISTRY TEST : ORGANOMETALLIC MPOUNDS Date : [ANSWERS] PART-A 1. (b) 2. (b). (c). (c). (b). (d) 7. (d) 8. (a) 9. (d) 10. (c) PART-B 11. (d) 12. (a) 1. (b) 1. (d) 1. (a) 1. (a) 17. (c) 18. (d) 19. (a) 20. (d)