[Co(NH₃)₅(NO₂)]Cl₂🧲 YaMR

Pentaamminkobalt(III) nitro-izomer xlorid

Nitro-pentaamminkobalt(III) (sariq)

M = 261.44 g/mol • CAS: 14970-14-0

Linkage IzomerizmN-bondedDiamagnitPhoto-salient

← Birikmalar katalogi

YaMRLinkage IzomerizmJorgensen (1894)Photo-salientDiamagnit

[Co(NH₃)₅(NO₂)]Cl₂

261.44 g/mol

nitro-pentaamminkobalt(III) — "Linkage izomerizm, DSC termik izomerlanish, photo-salient effect"

YaMR spektroskopiya yordamida linkage izomerizmni o'rganish. N-bog'langan nitro izomer (sariq) va O-bog'langan nitrito izomer (qizil). ¹H: 3.5 ppm (NH₃, singlet), ¹⁵N: 650 ppm (NO₂, N-bonded). Jorgensen (1894) kashfiyoti, DSC termik izomerlanish, photo-salient effect (Naumov 2013).

Metall ioni

Co³⁺ (d⁶)

Magnit

Diamagnit

Simmetriya

C₄ᵥ

Elektrolit

1:2

🔬 Kristall maydon nazariyasi (Crystal Field Theory)

Nima uchun bu kompleks diamagnit? Co³⁺ — d⁶ elektron konfiguratsiya. NH₃ va NO₂⁻ — kuchli maydon ligandlari. Δ_o (23,600 cm⁻¹) > P (juftlanish energiyasi, 21,000 cm⁻¹) → past spinli (low-spin), barcha elektronlar juftlangan → diamagnit.

Elektron konfiguratsiya

Metall ioni:Co³⁺

Elektron konfiguratsiya:[Ar] 3d⁶

d-elektronlar soni:6

Spin holati:Past spinli (low-spin)

Orbital to'ldirilishi:t₂g⁶ eg⁰

Toq elektronlar:0

Magnit momenti:0 BM (diamagnit)

Kristall maydon parametrlari

Δ_o (10Dq):Δo ≈ 23,600 cm⁻¹ (2.93 eV)

Racah B:B ≈ 580 cm⁻¹ (erkin ion B₀ = 1020 cm⁻¹)

β (nefelauxetik):β = B/B₀ ≈ 0.57

Juftlanish energiyasi P:P ≈ 21,000 cm⁻¹

CFSE:CFSE = -2.4Δo + P ≈ -56,640 + 21,000 = -35,640 cm⁻¹

Spektrokimyoviy qator va rang

Spektrokimyoviy qator: NO₂⁻ — kuchli maydon ligandi (I⁻ < Br⁻ < Cl⁻ < F⁻ < OH⁻ < H₂O < NH₃ < en < NO₂⁻ < CN⁻)

Nima uchun past spinli? Δo (23,600) > P (21,000) → past spinli, diamagnit

Rang sababi: ¹A₁g → ¹T₁g (F) o'tish ~22,000 cm⁻¹ (455 nm, ko'k yutilish → sariq rang)

d-orbital bo'linish diagrammasi

_gd_x²-y², d_z²+0.6Δ_ot_2gd_xy, d_xz, d_yz-0.4Δ_o↑↓↑↓↑↓↑↓↑↓↑↓Δ_o

📐 Simmetriya va spektral tanlash qoidalari

C₄ᵥ nuqtaviy guruhi: [Co(NH₃)₅(NO₂)]²⁺ oktaedr geometriyada, lekin bitta NH₃ NO₂⁻ ga almashtirilgan → simmetriya O_h dan C₄ᵥ ga tushadi. Bu simmetriya IR, Raman va YaMR spektrlarini belgilaydi.

Simmetriya elementlari

Nuqtaviy guruh:C₄ᵥ

Guruh tartibi:8

Simmetriya elementlari:E, 2C₄, C₂, 2σᵥ, 2σᵈ

Spektral faollik

IR faol:A1, B1, B2, E — IR faol (dipol momenti o'zgaradi)

Raman faol:A1, B1, B2, E — Raman faol (polyarizatsiya o'zgaradi)

O'zaro istisno:C₄ᵥ da IR va Raman ustma-ust tushadi (markaziy simmetriya yo'q)

YaMR uchun ekvivalentlik

C₄ᵥ simmetriya: 5 ta NH₃ dan 4 tasi ekvivalent (axial), 1 tasi (trans-NO₂) alohida. Amaliyotda tez almashinish tufayli barcha 5 NH₃ ekvivalent ko'rinadi.

C₄ᵥ karakterlar jadvali

Irrep	E	2C₄	C₂	2σᵥ	2σᵈ	Funksiyalar
A1	1	1	1	1	1	z, x²+y², z²
A2	1	1	1	-1	-1	Rz
B1	1	-1	1	1	-1	x²-y²
B2	1	-1	1	-1	1	xy
E	2	0	-2	0	0	(x,y), (Rx,Ry), (xz,yz)

🔗 Linkage izomerizm — N-bonded vs O-bonded

Nitro izomer (N-bonded)

Rang:Sariq

Bog'lanish:Co-N (N-bonded)

¹H YaMR:3.5 ppm (singlet)

¹⁵N YaMR:650 ppm

Co-N bog' uzunligi:1.93-1.96 Å

Nitrito izomer (O-bonded)

Rang:Qizil

Bog'lanish:Co-O (O-bonded)

¹H YaMR:3.5 ppm (singlet)

¹⁵N YaMR:580 ppm (70 ppm farq)

Co-O bog' uzunligi:~2.05 Å

Linkage izomerizm: NO₂⁻ ambidentat ligand — N yoki O orqali bog'lanishi mumkin. Nitro izomer (N-bonded, sariq) va nitrito izomer (O-bonded, qizil). ¹⁵N YaMR da 70 ppm farq — linkage izomerlarni aniq farqlash.

📏 Strukturaviy parametrlar

Bog' uzunliklari

Co-N (NO₂, nitro):1.93-1.96 Å (Co-N nitro, trans-NH₃ ga nisbatan qisqaroq)

Co-N (NH₃, trans-NO₂):1.97-1.99 Å (Co-N NH₃ trans-NO₂)

Co-N (NH₃, cis-NO₂):1.96-1.98 Å (Co-N NH₃ cis-NO₂)

N-O (nitro):1.12-1.14 Å (N-O nitro, qo'sh bog' xarakterli)

Bog' burchaklari

O-N-O (nitro):115-117° (O-N-O nitro, sp² gibridlanish)

N-Co-N:90° (cis NH₃-NH₃), 180° (trans NH₃-NO₂)

Trans-effekt

Trans-effekt tartibi:NO₂⁻ > NH₃ (NO₂⁻ kuchliroq trans-effekt)

Mexanizm:σ-bog'lanish va π-qaytish (NO₂⁻ π-akseptor)

Taqqoslash: [Co(NH₃)₆]³⁺ da Co-N = 1.97 Å. NO₂⁻ trans-effekt: NH₃ ga nisbatan kuchliroq trans-effekt.

🧲 YaMR nazariyasi — chuqur tahlil

Nima uchun aynan shu kimyoviy siljishlar? Har bir yadro uchun kimyoviy siljishning fizik ma'nosini, relaksatsiya mexanizmlarini va spektral xususiyatlarini chuqur o'rganamiz.

¹H (I = 1/2, 100% tabiiy)

Kimyoviy siljish:

3.5 ppm (NH₃)

Multiplicity:

Singlet (C₄ᵥ simmetriyada barcha 5 NH₃ ekvivalent, yoki tez ligand almashinish)

Chiziq kengligi:

~5-15 Hz (o'tkir, diamagnit)

T₁ relaksatsiya:

T₁ ≈ 1-3 s (dipol-dipol mexanizm, ¹H-¹⁴N bog'lanish)

Nima uchun bu siljish?

NH₃ ligand — Co³⁺ ga bog'langan. Co³⁺ kuchli elektropozitiv → NH₃ protonlari deshielded (odatdagi NH₃ dan yuqori ppm). Referens: erkin NH₃ ~0.9 ppm, kompleksda 3.5 ppm → Δδ = +2.6 ppm (deshielding, metal effekti).

Spin-spin bog'lanish:

¹J(¹H-¹⁵N) ≈ 5-10 Hz (¹⁵N tabiiy 0.37%, shuning uchun kuzatilmaydi). ¹⁵N bilan boyitilsa, dublet ko'rinadi.

🔥 Termodinamik va kinetik parametrlar

Izomerlanish termodinamikasi

Reaksiya:[Co(NH₃)₅(ONO)]²⁺ → [Co(NH₃)₅(NO₂)]²⁺

Yo'nalish:Nitrito → Nitro (ekzotermik, termodinamik jihatdan qulay)

ΔH:ΔH ≈ -10 dan -15 kJ/mol (ekzotermik, DSC)

ΔS:ΔS ≈ -5 dan -15 J/(mol·K) (biroz tartibli)

ΔG (298 K):ΔG ≈ -7 dan -11 kJ/mol (298 K da)

K (muvozanat):K ≈ 10-100 (nitro izomer ustun)

Kinetik parametrlar

Eₐ (aktivatsiya):Eₐ ≈ 100-160 kJ/mol (katta, inert kompleks)

k (tezlik konstantasi):k ≈ 10⁻⁵ dan 10⁻³ s⁻¹ (25°C da, sekin)

t₁/₂ (yarim yemirilish):t₁/₂ ≈ soatlab-kunlab (qorong'ida, xona haroratida)

Mexanizm:Intramolekulyar (ONO → NO₂ qayta tashkil topish)

Inertlik (Inertness)

Nima uchun inert? Co³⁺ d⁶ past spinli — katta CFSE, inert (sekin ligand almashinish)

Taqqoslash: Co²⁺ (d⁷) labil, Fe³⁺ (d⁵) o'rtacha, Cr³⁺ (d³) juda inert

🧲 YaMR signallar (batafsil)

Yadro	Ligand	δ (ppm)	Multiplicity	J (Hz)	Integration	Izohlar
¹H	NH₃ (barcha 5 ta)	3.5	singlet	—	15H	Barcha 5 ta NH₃ ekvivalent (C₄ᵥ simmetriya). Inert kompleks — sekin almashinish. Deshielded (+2.6 ppm) — Co³⁺ elektropozitiv.
¹⁵N	NO₂ (N-bonded)	650	singlet	—	1N	N-bog'langan izomer. ¹⁵N YaMR da 650 ppm da signal. Nitrito izomerda 580 ppm (70 ppm farq). Sezgirlik past (0.37% tabiiy).
⁵⁹Co	Co markaz	8120	singlet (keng)	—	1Co	⁵⁹Co YaMR da 8120 ppm atrofida signal. Keng chiziq (~500-2000 Hz, kvadrupol, I=7/2). CQ ≈ 10-30 MHz.

📈 Interaktiv YaMR spektr simulyatsiyasi (¹H)

Kimyoviy siljishni (δ, ppm) o'zgartiring. Signallar qanday o'zgarishini ko'ring.

Kimyoviy siljish (δ): 3.5 ppm

0 ppm (TMS)3.5 ppm (NH₃)10 ppm

Kimyoviy siljish:

3.5 ppm

Signal:

¹H: NH₃ (singlet, 15H)

Ligand:

NH₃ (barcha 5 ta ekvivalent)

🔥 Termik izomerlanish kinetikasi (DSC)

ScienceDirect S0040603103003617: DSC (Differential Scanning Calorimetry) yordamida termik izomerlanish kinetikasi o'rganilgan. Nitrito → nitro konversiyasi ekzotermik (ΔH < 0). Qisman qaytar (partially reversible).

Pathway (1): nitro → endo-nitrito → exo-nitrito

Pathway (2): nitro → exo-nitrito

ωB97XD/6-31+G(d,p) bo'yicha: Pathway (1) through endo-nitrito eng past energiya yo'li (38.16 kcal/mol). Pathway (2) through TS3 (41.76 kcal/mol) — yuqoriroq energiya. Pathway (1) preferred.

💡 Photo-salient effect (Naumov 2013)

Naumov (2013): UV yorug'lik ta'sirida [Co(NH₃)₅ONO](NO₃)Cl kristali sakraydi (photo-salient effect). Photo-isomerization (nitro → nitrito) jarayonida [Co(NH₃)₅ONO]²⁺ local source of strains sifatida xizmat qiladi.

Photo-salient effect

Effect:Kristall sakraydi

Mexanizm:Photo-isomerization

Strain source:[Co(NH₃)₅ONO]²⁺

Kashfiyotchi:Naumov (2013)

Qo'llanish

Dynamic molecular crystals:✓

Photo-responsive materials:✓

Tunable optical materials:✓

Molecular devices:✓

🧮 ωB97XD/6-31+G(d,p) hisob-kitoblari (PMC9077707)

PMC9077707: ωB97XD/6-31+G(d,p) yordamida nitro/nitrito isomerization mexanizmi o'rganilgan. Pathway (1) through endo-nitrito eng past energiya yo'li.

Hisob-kitob metodi

Method:ωB97XD/6-31+G(d,p)

Co-N bog' uzunligi:1.97-2.01 Å

PJTE stabilization:~750 cm⁻¹

Manba:PMC9077707

Reaction pathways

Pathway (1):nitro → TS1 (38.16) → endo-nitrito → TS2 (9.68) → exo-nitrito

Pathway (2):nitro → TS3 (41.76) → exo-nitrito

Preferred:Pathway (1) (eng past energiya)

💎 Qattiq holat YaMR (Solid-State NMR)

CP/MAS (Cross-Polarization / Magic Angle Spinning): Erituvchisiz, kristall namuna uchun. Photo-salient effect mexanizmini qattiq holatda o'rganish uchun juda muhim.

Afzalliklar

✓ Kristall namuna
✓ Erituvchi kerak emas
✓ Polimorfizm o'rganish

Parametrlar

⁵⁹Co CQ:CQ(⁵⁹Co) ≈ 10-30 MHz (katta, kvadrupol)

⁵⁹Co η:η ≈ 0-0.3 (C₄ᵥ simmetriyaga yaqin)

¹H MAS:¹H MAS — NH₃ signali 3.5 ppm da (eritma bilan bir xil)

Qo'llanilishi: Polimorfizm, termik izomerlanishni qattiq holatda kuzatish, photo-salient effect mexanizmi

📜 Tarixiy kontekst

Jorgensen (1894)

Olim:Sophus Mads Jorgensen (Daniya)

Yil:1894

Yutuq:Birinchi linkage izomerlarni sintez qildi va tavsifladi

Usul:[Co(NH₃)₅(NO₂)]Cl₂ (sariq) va [Co(NH₃)₅(ONO)]Cl₂ (qizil) ajratdi

Werner (1913)

Olim:Alfred Werner (Shveytsariya)

Yil:1913

Yutuq:Koordinatsion nazariya (Nobel mukofoti)

Hissa:Linkage izomerizm tushunchasini nazariy jihatdan tushuntirdi

Zamonaviy davr

YaMR:1960-yillardan YaMR orqali aniq farqlash (¹⁵N, ⁵⁹Co)

Hisob-kitob:ωB97XD, DFT, CCSD hisob-kitoblari (2010-yillar)

Foto-kimyo:Naumov (2013) — photo-salient effect kashfiyoti

🔄 Taqqoslash — boshqa linkage izomerlar

Kompleks	Ligand	Rang	YaMR siljish	Barqarorlik	Izomerlanish
[Co(NH₃)₅(NO₂)]²⁺	NO₂⁻ (N-bonded)	Sariq	¹⁵N: 650 ppm	Termodinamik jihatdan barqaror	Nitrito → Nitro (ekzotermik)
[Co(NH₃)₅(ONO)]²⁺	ONO⁻ (O-bonded)	Qizil	¹⁵N: 580 ppm	Metastabil (sekin nitro ga aylanadi)	Nitrito → Nitro (sekin, qorong'ida)
[Co(NH₃)₅(NCS)]²⁺	NCS⁻ (N-bonded)	Sariq-to'q sariq	¹³C: ~120 ppm (NCS)	Barqaror	SCN → NCS (kuchli maydon)
[Co(NH₃)₅(SCN)]²⁺	SCN⁻ (S-bonded)	To'q sariq	¹³C: ~110 ppm (SCN)	Kuchsiz maydon, kam barqaror	SCN → NCS (tezroq)
[Ru(NH₃)₅(SO₂)]²⁺	SO₂ (S-bonded, η¹)	Sariq	¹H: o'zgaruvchan	Linkage izomerlar (η¹, η²)	η¹ → η² (foto-kimyoviy)

🧪 Laboratoriyani 0 dan bajarish tartibi

⚠️ Xavfsizlik tayyorgarligi

Qo'lqop, ko'zoynak. NO₂⁻ toksik. Co³⁺ zaharli. Qorong'ida saqlash (nitrito → nitro konversiyasi).

📚 Nazariy izoh:

NO₂⁻ toksik. [Co(NH3)5(NO2)]Cl2 qorong'ida saqlanishi kerak — nitrito izomerga konversiyasi sodir bo'ladi.

Vaqt: 15 daq

Sof [Co(NH₃)₅(NO₂)]Cl₂ ni tayyorlash

YaMR spektrometrni tayyorlash

Namuna tayyorlash

¹H YaMR spektrini olish

¹⁵N YaMR spektrini olish (ixtiyoriy)

⁵⁹Co YaMR spektrini olish (ixtiyoriy)

Nitrito izomer tekshirish (ixtiyoriy)

⚠️ Halaqit beruvchi omillar

Manba	Ta'sir	Jiddiylik	Yechim
Nitrito izomer aralashmasi	¹⁵N YaMR da 580 ppm da qo'shimcha signal (nitro dan 70 ppm farq)	Yuqori	Sof nitro izomer ishlatish. Qorong'ida saqlash (nitrito → nitro konversiyasi).
Photo-isomerlanish	UV yorug'lik ta'sirida nitro → nitrito konversiyasi	Yuqori	Qorong'ida saqlash. UV yorug'likdan saqlash.
⁵⁹Co kvadrupol kengayishi	⁵⁹Co signallari juda keng (~500-2000 Hz), sezgirlik past	O'rta	Keng chiziqli texnikalar, yuqori konsentratsiya, uzoq vaqt skanerlash.
¹⁵N past sezgirlik	¹⁵N tabiiy tarqalishi 0.37%, sezgirlik ¹H dan 5700 marta past	O'rta	¹⁵N bilan boyitish, 1000-10000 skan, yuqori konsentratsiya.
Erituvchi cho'qqilari	D₂O da HOD signal 4.7 ppm da — NH₃ signaliga yaqin	O'rta	DMSO-d₆ ishlatish (NH₃ signali 3.5 ppm da, HOD dan uzoq).
Paramagnit aralashmalar	Signallarni kengaytiradi va siljitadi	O'rta	Sof namuna ishlatish. Paramagnit aralashmalardan saqlash.

📚 Tanlangan omilning nazariy izohi:

Nitrito izomerda ¹⁵N signal 580 ppm da (nitro dan 70 ppm past). Qorong'ida nitrito sekin nitro ga aylanadi.

🔬 Kengaytiruvchi metodlar

DSC (Differential Scanning Calorimetry)

Termik izomerlanish kinetikasi (nitrito → nitro)

✓ Afzalliklar:

• Termik izomerlanish kinetikasi
• ΔH, ΔS parametrlari
• Qaytarlik darajasi

✗ Kamchiliklar:

• Uzoq vaqt
• Murakkab tahlil
• Faqat termik izomerlanish

Eng yaxshi:

Termik izomerlanish kinetikasi, DSC

Misollar:

ScienceDirect S0040603103003617 — DSC termik izomerlanish

✅ Asosiy xulosalar

Kristall maydon nazariyasi: Co³⁺ (d⁶), past spinli (t₂g⁶ eg⁰), diamagnit, Δ_o ≈ 23,600 cm⁻¹
Linkage izomerizm: NO₂⁻ ambidentat ligand (N-bonded vs O-bonded)
Simmetriya (C₄ᵥ): IR va Raman faol, YaMR uchun ekvivalentlik
Jorgensen (1894): Linkage izomerizm kashfiyoti
¹H YaMR: 3.5 ppm (NH₃, singlet, 15H), deshielded (+2.6 ppm) — Co³⁺ elektropozitiv
¹⁵N YaMR: 650 ppm (N-bonded), nitrito da 580 ppm (70 ppm farq). Past sezgirlik (0.37%)
⁵⁹Co YaMR: 8120 ppm, keng chiziq (~500-2000 Hz), kvadrupol (I=7/2), CQ ≈ 10-30 MHz
Strukturaviy: Co-N(NO₂) 1.93-1.96 Å, Co-N(NH₃) 1.96-1.99 Å, O-N-O 115-117°
Termodinamik: ΔG ≈ -7 dan -11 kJ/mol, Eₐ ≈ 100-160 kJ/mol (inert)
DSC termik izomerlanish: Nitrito → nitro (ekzotermik, qisman qaytar)
Photo-salient effect: UV yorug'lik ta'sirida kristall sakraydi (Naumov 2013)
ωB97XD/6-31+G(d,p): Pathway (1) through endo-nitrito (eng past energiya)
Qattiq holat YaMR: CP/MAS, ⁵⁹Co CQ ≈ 10-30 MHz, η ≈ 0-0.3

← Birikmalar katalogi Nitrito izomer →