Metal Carbonyls PDF

~ -- - _!:.- ':"L~n'.1'.-;:Cu:.:;'b:..O-n~y-ls_' - - - - - - - -- - - - - - - - - - - - - - ---1( I) ' ' J fhC 1,ond ,-iructure Is UP1l0r1ed by !lie ro11c1lon When 11n 11lcohohllllls ol the metal a to m. CO groo 1 bound to the metal atom by simp...

~ -- - _!:.- ':"L~n'.1'.-;:Cu:.:;'b:..O-n~y-ls_' - - - - - - - -- - - - - - - - - - - - - - ---1( I) ' ' J fhC 1,ond ,-iructure Is UP1l0r1ed by !lie ro11c1lon When 11n 11lcohohllllls ol the metal a to m. CO groo 1 bound to the metal atom by simple CO ionic bond 1--lenc.e. rhesc CO qroue or~ repina,ble by an:S Ol:: ( D - I O ) r - - - -- - - -- ---R_ca_ r_rn_n..;g_e_m_c_n_ts_· o_n_d_C_h_cr_TI_ ls_try_o_r_G_r_ o _up_ E_ le...:rn.::e~n~ l. The NI-C bond lengih ~ I.SO Awhich LS shoner than usual NI-C ~,ngle bond length ( I 82 A) found 1 carbonyb n 2 The C-0 bond length is I 15 A which b forger than the C-0 bond length 1n CO molecule ( 1.128 A) 3 Raman spectrnl srudles have revealed rhat the o xygen aiom LS 1nply bonded to carbon atom In the CO g,-oup Thus Nickel a tom is Nickel carbonyl Should be sp3 hybndlsed O ld Orbital Dlapam Ni2s =1522s 22pb3s23p6 3d84s2 3d 4s 4p Ni ground state atom lt.1.lr-Llt-LI r Ir I [IT) I I Ni atom Nl(CO) in Ir,1, Ir,1, Ir,1,1 r.1. Ir.1. I □ 4 Nt(CO) molecule 4 Ii J, IT.!. Ii.!.l i.!. IiJ. I E] lxxlxxlxxl I I I I C C C C Ill Ill Ill Ill 0 0 0 0 "'Sp 3 hybridisation oi Ni alom in Ni(CO)4 molecule" Recent Orbital Diagram 3d 4s 4p Ni ground stare a tom ltJ.jr,1,jr.1.1 r Ir I [ill I I N1 in Ni(C0)4 o1om lrilt!lt!lrlrl W lr l I ltllt.!.lttl i Ii I [I] f1TTl 1====£c- i~~ -7~II II Ill Ill 0 0 Q Q New orbital diagram of Ni(CO)4 molecule 0 II C ,--./NI ~ 0,,,. C / ' ~ Ca 0 C _____ ________ Bond roucrure in 0 ______ r-:,(CO). molecule..------  UNIT-VII Metal Carbonyl s 1 Metal Carbonyls.__.:ire regarded as the co-ordinatio n compounds lormed between the electron donor carbonyl gyoup (CfJ. j ~ ~ , _,·.ro ~-a1,m1 transition m etals. The electronic conllguralion of CO molecule md1c.ates that II contain$ a lone ,, ;?lectr0ns on carbon and oxygen ato m each. Thus. carbon a rom ol CO molecul1< md1cale!t that 11 1 ;, ,ns a Jone pair ol electro ns o n carbon and oxyge n ato m each So, carbon atom of CO molecule can 3 ·'\a: 1rs electron pair to a transition metal atom (M ) to fo rm O C-, M coordinate bond Smee the electrons --.mg OC _. M bond are supplied only by CO mo lecules. metal a rom in carbonyls IS said to be m zer,.., -,ja!!on state. In metal carbonyls CO mo lecules ad as neutral ligands Classificatio n : Heiber classified the metal carbonyls into two groups · Mononuclear Carbonyls : These carbo nyls have the gene ral lormula M(CO ],, which con tain any one a.om of !he metal per molecule o f the carbonyl For example. N1(COl4, Fe(C0)5 and Cr( C0)6 elC Mononuclear carbonyls are generally formed by meta ls havi ng even ato mic numbers Such carbon~·b are readily soluble in organic mo re volatile rhan the o the rs ltl Terracarbonyls like Ni(C0)4 have tetrahedral s hape 1u1 Pentacarbo nyls like Fe (C0) 5. Os(C0)5 have trigo nal bipyra m rdal shape. 11ii1Hexacarbonyls like Cr(C0) 6 have octahedral shape co co oc "- / co Ni cc" I Fe - CO oc " I., ,. , co Cr oc / "- co QC/ I oc / 1 -'- CC.1 co Ci 1 Ter,..,1,ec.1,,,1 Tngonal bipyranudal Ooah~dr,,1 Ni (CO)~ Fe (CO)~ Cr 1cn1,, Structure of 111ono nuclen_r ca rbonyl l'olynucJ C ear arbonyls : T hese have the general fo rmuld M , 1COJ \,hrch co ntJ11 , m ore 1har "'., I I 1.,,on yl Nl(CO) ,::;, I>/..__~ n and X-rny diffnlction studies have shown that Ni(CO) molecule has a tetrahedral s hape ~-o Unear units. 0 Ill C o--c ca o C Ill 0 :.c:.__ ~ral , tructure of N _ _ _ _ _ _ _ _ _ _ _T;.:e:..:tTah..=. c~ke::l_:rurbo,= =.:.'"-Y-1 _ _ _ _ _ _ __ _ __ _  ~ l" l II ,t. ~ 1\ u , ' Uh t.,I , uh, 11 n I 111,,. 1111 d 111 "+ I 11 ,1 u 111111 ti , oh1t11l1 I, 1111, ,J di' ,,,t,1tol,1 nt ~ t hit' ,,,f f.it'J'f'411 \ /tr r f(', 1.,,,,l.,p\\tlh th, 1.-,, 1\tn u ,11llltt11,dho1111l111nl, t1I t ' I hi , '""'.., " '. 11,,""'"'' ,,. Hlh Ill"" ,1111111,.....,1/1 11,,,.,11..,tw, ,,n ,,... ,,,..11,J "1 "'"J ttw ,...,,nd OJ n* di: -· \ il,11, I I,""" 111 1111 fl,tllh In""' "'""'' (X/ 11ln111 I 1111ly /\ ,111111111 r/11 n- rN4't\,,p 'Yu.Ill In I}.., rfli>1t1 p.,,,,_, ~ ,.,,,,,, "' \ p l.,n, w h ll It I u I... h11w 11 l1 1 tl1u hfiiH '.~""'.':' ·:,-0, ,. '~· ,,